diff options
Diffstat (limited to 'gdb/gdbserver/linux-low.c')
| -rw-r--r-- | gdb/gdbserver/linux-low.c | 7492 |
1 files changed, 0 insertions, 7492 deletions
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c deleted file mode 100644 index 676dea2..0000000 --- a/gdb/gdbserver/linux-low.c +++ /dev/null @@ -1,7492 +0,0 @@ -/* Low level interface to ptrace, for the remote server for GDB. - Copyright (C) 1995-2020 Free Software Foundation, Inc. - - This file is part of GDB. - - This program is free software; you can redistribute it and/or modify - it under the terms of the GNU General Public License as published by - the Free Software Foundation; either version 3 of the License, or - (at your option) any later version. - - This program is distributed in the hope that it will be useful, - but WITHOUT ANY WARRANTY; without even the implied warranty of - MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the - GNU General Public License for more details. - - You should have received a copy of the GNU General Public License - along with this program. If not, see <http://www.gnu.org/licenses/>. */ - -#include "server.h" -#include "linux-low.h" -#include "nat/linux-osdata.h" -#include "gdbsupport/agent.h" -#include "tdesc.h" -#include "gdbsupport/rsp-low.h" -#include "gdbsupport/signals-state-save-restore.h" -#include "nat/linux-nat.h" -#include "nat/linux-waitpid.h" -#include "gdbsupport/gdb_wait.h" -#include "nat/gdb_ptrace.h" -#include "nat/linux-ptrace.h" -#include "nat/linux-procfs.h" -#include "nat/linux-personality.h" -#include <signal.h> -#include <sys/ioctl.h> -#include <fcntl.h> -#include <unistd.h> -#include <sys/syscall.h> -#include <sched.h> -#include <ctype.h> -#include <pwd.h> -#include <sys/types.h> -#include <dirent.h> -#include <sys/stat.h> -#include <sys/vfs.h> -#include <sys/uio.h> -#include "gdbsupport/filestuff.h" -#include "tracepoint.h" -#include "hostio.h" -#include <inttypes.h> -#include "gdbsupport/common-inferior.h" -#include "nat/fork-inferior.h" -#include "gdbsupport/environ.h" -#include "gdbsupport/gdb-sigmask.h" -#include "gdbsupport/scoped_restore.h" -#ifndef ELFMAG0 -/* Don't include <linux/elf.h> here. If it got included by gdb_proc_service.h - then ELFMAG0 will have been defined. If it didn't get included by - gdb_proc_service.h then including it will likely introduce a duplicate - definition of elf_fpregset_t. */ -#include <elf.h> -#endif -#include "nat/linux-namespaces.h" - -#ifdef HAVE_PERSONALITY -# include <sys/personality.h> -# if !HAVE_DECL_ADDR_NO_RANDOMIZE -# define ADDR_NO_RANDOMIZE 0x0040000 -# endif -#endif - -#ifndef O_LARGEFILE -#define O_LARGEFILE 0 -#endif - -#ifndef AT_HWCAP2 -#define AT_HWCAP2 26 -#endif - -/* Some targets did not define these ptrace constants from the start, - so gdbserver defines them locally here. In the future, these may - be removed after they are added to asm/ptrace.h. */ -#if !(defined(PT_TEXT_ADDR) \ - || defined(PT_DATA_ADDR) \ - || defined(PT_TEXT_END_ADDR)) -#if defined(__mcoldfire__) -/* These are still undefined in 3.10 kernels. */ -#define PT_TEXT_ADDR 49*4 -#define PT_DATA_ADDR 50*4 -#define PT_TEXT_END_ADDR 51*4 -/* BFIN already defines these since at least 2.6.32 kernels. */ -#elif defined(BFIN) -#define PT_TEXT_ADDR 220 -#define PT_TEXT_END_ADDR 224 -#define PT_DATA_ADDR 228 -/* These are still undefined in 3.10 kernels. */ -#elif defined(__TMS320C6X__) -#define PT_TEXT_ADDR (0x10000*4) -#define PT_DATA_ADDR (0x10004*4) -#define PT_TEXT_END_ADDR (0x10008*4) -#endif -#endif - -#ifdef HAVE_LINUX_BTRACE -# include "nat/linux-btrace.h" -# include "gdbsupport/btrace-common.h" -#endif - -#ifndef HAVE_ELF32_AUXV_T -/* Copied from glibc's elf.h. */ -typedef struct -{ - uint32_t a_type; /* Entry type */ - union - { - uint32_t a_val; /* Integer value */ - /* We use to have pointer elements added here. We cannot do that, - though, since it does not work when using 32-bit definitions - on 64-bit platforms and vice versa. */ - } a_un; -} Elf32_auxv_t; -#endif - -#ifndef HAVE_ELF64_AUXV_T -/* Copied from glibc's elf.h. */ -typedef struct -{ - uint64_t a_type; /* Entry type */ - union - { - uint64_t a_val; /* Integer value */ - /* We use to have pointer elements added here. We cannot do that, - though, since it does not work when using 32-bit definitions - on 64-bit platforms and vice versa. */ - } a_un; -} Elf64_auxv_t; -#endif - -/* Does the current host support PTRACE_GETREGSET? */ -int have_ptrace_getregset = -1; - -/* LWP accessors. */ - -/* See nat/linux-nat.h. */ - -ptid_t -ptid_of_lwp (struct lwp_info *lwp) -{ - return ptid_of (get_lwp_thread (lwp)); -} - -/* See nat/linux-nat.h. */ - -void -lwp_set_arch_private_info (struct lwp_info *lwp, - struct arch_lwp_info *info) -{ - lwp->arch_private = info; -} - -/* See nat/linux-nat.h. */ - -struct arch_lwp_info * -lwp_arch_private_info (struct lwp_info *lwp) -{ - return lwp->arch_private; -} - -/* See nat/linux-nat.h. */ - -int -lwp_is_stopped (struct lwp_info *lwp) -{ - return lwp->stopped; -} - -/* See nat/linux-nat.h. */ - -enum target_stop_reason -lwp_stop_reason (struct lwp_info *lwp) -{ - return lwp->stop_reason; -} - -/* See nat/linux-nat.h. */ - -int -lwp_is_stepping (struct lwp_info *lwp) -{ - return lwp->stepping; -} - -/* A list of all unknown processes which receive stop signals. Some - other process will presumably claim each of these as forked - children momentarily. */ - -struct simple_pid_list -{ - /* The process ID. */ - int pid; - - /* The status as reported by waitpid. */ - int status; - - /* Next in chain. */ - struct simple_pid_list *next; -}; -struct simple_pid_list *stopped_pids; - -/* Trivial list manipulation functions to keep track of a list of new - stopped processes. */ - -static void -add_to_pid_list (struct simple_pid_list **listp, int pid, int status) -{ - struct simple_pid_list *new_pid = XNEW (struct simple_pid_list); - - new_pid->pid = pid; - new_pid->status = status; - new_pid->next = *listp; - *listp = new_pid; -} - -static int -pull_pid_from_list (struct simple_pid_list **listp, int pid, int *statusp) -{ - struct simple_pid_list **p; - - for (p = listp; *p != NULL; p = &(*p)->next) - if ((*p)->pid == pid) - { - struct simple_pid_list *next = (*p)->next; - - *statusp = (*p)->status; - xfree (*p); - *p = next; - return 1; - } - return 0; -} - -enum stopping_threads_kind - { - /* Not stopping threads presently. */ - NOT_STOPPING_THREADS, - - /* Stopping threads. */ - STOPPING_THREADS, - - /* Stopping and suspending threads. */ - STOPPING_AND_SUSPENDING_THREADS - }; - -/* This is set while stop_all_lwps is in effect. */ -enum stopping_threads_kind stopping_threads = NOT_STOPPING_THREADS; - -/* FIXME make into a target method? */ -int using_threads = 1; - -/* True if we're presently stabilizing threads (moving them out of - jump pads). */ -static int stabilizing_threads; - -static void linux_resume_one_lwp (struct lwp_info *lwp, - int step, int signal, siginfo_t *info); -static void linux_resume (struct thread_resume *resume_info, size_t n); -static void stop_all_lwps (int suspend, struct lwp_info *except); -static void unstop_all_lwps (int unsuspend, struct lwp_info *except); -static void unsuspend_all_lwps (struct lwp_info *except); -static int linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid, - int *wstat, int options); -static int linux_wait_for_event (ptid_t ptid, int *wstat, int options); -static struct lwp_info *add_lwp (ptid_t ptid); -static void linux_mourn (struct process_info *process); -static int linux_stopped_by_watchpoint (void); -static void mark_lwp_dead (struct lwp_info *lwp, int wstat); -static int lwp_is_marked_dead (struct lwp_info *lwp); -static void proceed_all_lwps (void); -static int finish_step_over (struct lwp_info *lwp); -static int kill_lwp (unsigned long lwpid, int signo); -static void enqueue_pending_signal (struct lwp_info *lwp, int signal, siginfo_t *info); -static void complete_ongoing_step_over (void); -static int linux_low_ptrace_options (int attached); -static int check_ptrace_stopped_lwp_gone (struct lwp_info *lp); -static void proceed_one_lwp (thread_info *thread, lwp_info *except); - -/* When the event-loop is doing a step-over, this points at the thread - being stepped. */ -ptid_t step_over_bkpt; - -/* True if the low target can hardware single-step. */ - -static int -can_hardware_single_step (void) -{ - if (the_low_target.supports_hardware_single_step != NULL) - return the_low_target.supports_hardware_single_step (); - else - return 0; -} - -/* True if the low target can software single-step. Such targets - implement the GET_NEXT_PCS callback. */ - -static int -can_software_single_step (void) -{ - return (the_low_target.get_next_pcs != NULL); -} - -/* True if the low target supports memory breakpoints. If so, we'll - have a GET_PC implementation. */ - -static int -supports_breakpoints (void) -{ - return (the_low_target.get_pc != NULL); -} - -/* Returns true if this target can support fast tracepoints. This - does not mean that the in-process agent has been loaded in the - inferior. */ - -static int -supports_fast_tracepoints (void) -{ - return the_low_target.install_fast_tracepoint_jump_pad != NULL; -} - -/* True if LWP is stopped in its stepping range. */ - -static int -lwp_in_step_range (struct lwp_info *lwp) -{ - CORE_ADDR pc = lwp->stop_pc; - - return (pc >= lwp->step_range_start && pc < lwp->step_range_end); -} - -struct pending_signals -{ - int signal; - siginfo_t info; - struct pending_signals *prev; -}; - -/* The read/write ends of the pipe registered as waitable file in the - event loop. */ -static int linux_event_pipe[2] = { -1, -1 }; - -/* True if we're currently in async mode. */ -#define target_is_async_p() (linux_event_pipe[0] != -1) - -static void send_sigstop (struct lwp_info *lwp); -static void wait_for_sigstop (void); - -/* Return non-zero if HEADER is a 64-bit ELF file. */ - -static int -elf_64_header_p (const Elf64_Ehdr *header, unsigned int *machine) -{ - if (header->e_ident[EI_MAG0] == ELFMAG0 - && header->e_ident[EI_MAG1] == ELFMAG1 - && header->e_ident[EI_MAG2] == ELFMAG2 - && header->e_ident[EI_MAG3] == ELFMAG3) - { - *machine = header->e_machine; - return header->e_ident[EI_CLASS] == ELFCLASS64; - - } - *machine = EM_NONE; - return -1; -} - -/* Return non-zero if FILE is a 64-bit ELF file, - zero if the file is not a 64-bit ELF file, - and -1 if the file is not accessible or doesn't exist. */ - -static int -elf_64_file_p (const char *file, unsigned int *machine) -{ - Elf64_Ehdr header; - int fd; - - fd = open (file, O_RDONLY); - if (fd < 0) - return -1; - - if (read (fd, &header, sizeof (header)) != sizeof (header)) - { - close (fd); - return 0; - } - close (fd); - - return elf_64_header_p (&header, machine); -} - -/* Accepts an integer PID; Returns true if the executable PID is - running is a 64-bit ELF file.. */ - -int -linux_pid_exe_is_elf_64_file (int pid, unsigned int *machine) -{ - char file[PATH_MAX]; - - sprintf (file, "/proc/%d/exe", pid); - return elf_64_file_p (file, machine); -} - -static void -delete_lwp (struct lwp_info *lwp) -{ - struct thread_info *thr = get_lwp_thread (lwp); - - if (debug_threads) - debug_printf ("deleting %ld\n", lwpid_of (thr)); - - remove_thread (thr); - - if (the_low_target.delete_thread != NULL) - the_low_target.delete_thread (lwp->arch_private); - else - gdb_assert (lwp->arch_private == NULL); - - free (lwp); -} - -/* Add a process to the common process list, and set its private - data. */ - -static struct process_info * -linux_add_process (int pid, int attached) -{ - struct process_info *proc; - - proc = add_process (pid, attached); - proc->priv = XCNEW (struct process_info_private); - - if (the_low_target.new_process != NULL) - proc->priv->arch_private = the_low_target.new_process (); - - return proc; -} - -static CORE_ADDR get_pc (struct lwp_info *lwp); - -/* Call the target arch_setup function on the current thread. */ - -static void -linux_arch_setup (void) -{ - the_low_target.arch_setup (); -} - -/* Call the target arch_setup function on THREAD. */ - -static void -linux_arch_setup_thread (struct thread_info *thread) -{ - struct thread_info *saved_thread; - - saved_thread = current_thread; - current_thread = thread; - - linux_arch_setup (); - - current_thread = saved_thread; -} - -/* Handle a GNU/Linux extended wait response. If we see a clone, - fork, or vfork event, we need to add the new LWP to our list - (and return 0 so as not to report the trap to higher layers). - If we see an exec event, we will modify ORIG_EVENT_LWP to point - to a new LWP representing the new program. */ - -static int -handle_extended_wait (struct lwp_info **orig_event_lwp, int wstat) -{ - client_state &cs = get_client_state (); - struct lwp_info *event_lwp = *orig_event_lwp; - int event = linux_ptrace_get_extended_event (wstat); - struct thread_info *event_thr = get_lwp_thread (event_lwp); - struct lwp_info *new_lwp; - - gdb_assert (event_lwp->waitstatus.kind == TARGET_WAITKIND_IGNORE); - - /* All extended events we currently use are mid-syscall. Only - PTRACE_EVENT_STOP is delivered more like a signal-stop, but - you have to be using PTRACE_SEIZE to get that. */ - event_lwp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY; - - if ((event == PTRACE_EVENT_FORK) || (event == PTRACE_EVENT_VFORK) - || (event == PTRACE_EVENT_CLONE)) - { - ptid_t ptid; - unsigned long new_pid; - int ret, status; - - /* Get the pid of the new lwp. */ - ptrace (PTRACE_GETEVENTMSG, lwpid_of (event_thr), (PTRACE_TYPE_ARG3) 0, - &new_pid); - - /* If we haven't already seen the new PID stop, wait for it now. */ - if (!pull_pid_from_list (&stopped_pids, new_pid, &status)) - { - /* The new child has a pending SIGSTOP. We can't affect it until it - hits the SIGSTOP, but we're already attached. */ - - ret = my_waitpid (new_pid, &status, __WALL); - - if (ret == -1) - perror_with_name ("waiting for new child"); - else if (ret != new_pid) - warning ("wait returned unexpected PID %d", ret); - else if (!WIFSTOPPED (status)) - warning ("wait returned unexpected status 0x%x", status); - } - - if (event == PTRACE_EVENT_FORK || event == PTRACE_EVENT_VFORK) - { - struct process_info *parent_proc; - struct process_info *child_proc; - struct lwp_info *child_lwp; - struct thread_info *child_thr; - struct target_desc *tdesc; - - ptid = ptid_t (new_pid, new_pid, 0); - - if (debug_threads) - { - debug_printf ("HEW: Got fork event from LWP %ld, " - "new child is %d\n", - ptid_of (event_thr).lwp (), - ptid.pid ()); - } - - /* Add the new process to the tables and clone the breakpoint - lists of the parent. We need to do this even if the new process - will be detached, since we will need the process object and the - breakpoints to remove any breakpoints from memory when we - detach, and the client side will access registers. */ - child_proc = linux_add_process (new_pid, 0); - gdb_assert (child_proc != NULL); - child_lwp = add_lwp (ptid); - gdb_assert (child_lwp != NULL); - child_lwp->stopped = 1; - child_lwp->must_set_ptrace_flags = 1; - child_lwp->status_pending_p = 0; - child_thr = get_lwp_thread (child_lwp); - child_thr->last_resume_kind = resume_stop; - child_thr->last_status.kind = TARGET_WAITKIND_STOPPED; - - /* If we're suspending all threads, leave this one suspended - too. If the fork/clone parent is stepping over a breakpoint, - all other threads have been suspended already. Leave the - child suspended too. */ - if (stopping_threads == STOPPING_AND_SUSPENDING_THREADS - || event_lwp->bp_reinsert != 0) - { - if (debug_threads) - debug_printf ("HEW: leaving child suspended\n"); - child_lwp->suspended = 1; - } - - parent_proc = get_thread_process (event_thr); - child_proc->attached = parent_proc->attached; - - if (event_lwp->bp_reinsert != 0 - && can_software_single_step () - && event == PTRACE_EVENT_VFORK) - { - /* If we leave single-step breakpoints there, child will - hit it, so uninsert single-step breakpoints from parent - (and child). Once vfork child is done, reinsert - them back to parent. */ - uninsert_single_step_breakpoints (event_thr); - } - - clone_all_breakpoints (child_thr, event_thr); - - tdesc = allocate_target_description (); - copy_target_description (tdesc, parent_proc->tdesc); - child_proc->tdesc = tdesc; - - /* Clone arch-specific process data. */ - if (the_low_target.new_fork != NULL) - the_low_target.new_fork (parent_proc, child_proc); - - /* Save fork info in the parent thread. */ - if (event == PTRACE_EVENT_FORK) - event_lwp->waitstatus.kind = TARGET_WAITKIND_FORKED; - else if (event == PTRACE_EVENT_VFORK) - event_lwp->waitstatus.kind = TARGET_WAITKIND_VFORKED; - - event_lwp->waitstatus.value.related_pid = ptid; - - /* The status_pending field contains bits denoting the - extended event, so when the pending event is handled, - the handler will look at lwp->waitstatus. */ - event_lwp->status_pending_p = 1; - event_lwp->status_pending = wstat; - - /* Link the threads until the parent event is passed on to - higher layers. */ - event_lwp->fork_relative = child_lwp; - child_lwp->fork_relative = event_lwp; - - /* If the parent thread is doing step-over with single-step - breakpoints, the list of single-step breakpoints are cloned - from the parent's. Remove them from the child process. - In case of vfork, we'll reinsert them back once vforked - child is done. */ - if (event_lwp->bp_reinsert != 0 - && can_software_single_step ()) - { - /* The child process is forked and stopped, so it is safe - to access its memory without stopping all other threads - from other processes. */ - delete_single_step_breakpoints (child_thr); - - gdb_assert (has_single_step_breakpoints (event_thr)); - gdb_assert (!has_single_step_breakpoints (child_thr)); - } - - /* Report the event. */ - return 0; - } - - if (debug_threads) - debug_printf ("HEW: Got clone event " - "from LWP %ld, new child is LWP %ld\n", - lwpid_of (event_thr), new_pid); - - ptid = ptid_t (pid_of (event_thr), new_pid, 0); - new_lwp = add_lwp (ptid); - - /* Either we're going to immediately resume the new thread - or leave it stopped. linux_resume_one_lwp is a nop if it - thinks the thread is currently running, so set this first - before calling linux_resume_one_lwp. */ - new_lwp->stopped = 1; - - /* If we're suspending all threads, leave this one suspended - too. If the fork/clone parent is stepping over a breakpoint, - all other threads have been suspended already. Leave the - child suspended too. */ - if (stopping_threads == STOPPING_AND_SUSPENDING_THREADS - || event_lwp->bp_reinsert != 0) - new_lwp->suspended = 1; - - /* Normally we will get the pending SIGSTOP. But in some cases - we might get another signal delivered to the group first. - If we do get another signal, be sure not to lose it. */ - if (WSTOPSIG (status) != SIGSTOP) - { - new_lwp->stop_expected = 1; - new_lwp->status_pending_p = 1; - new_lwp->status_pending = status; - } - else if (cs.report_thread_events) - { - new_lwp->waitstatus.kind = TARGET_WAITKIND_THREAD_CREATED; - new_lwp->status_pending_p = 1; - new_lwp->status_pending = status; - } - -#ifdef USE_THREAD_DB - thread_db_notice_clone (event_thr, ptid); -#endif - - /* Don't report the event. */ - return 1; - } - else if (event == PTRACE_EVENT_VFORK_DONE) - { - event_lwp->waitstatus.kind = TARGET_WAITKIND_VFORK_DONE; - - if (event_lwp->bp_reinsert != 0 && can_software_single_step ()) - { - reinsert_single_step_breakpoints (event_thr); - - gdb_assert (has_single_step_breakpoints (event_thr)); - } - - /* Report the event. */ - return 0; - } - else if (event == PTRACE_EVENT_EXEC && cs.report_exec_events) - { - struct process_info *proc; - std::vector<int> syscalls_to_catch; - ptid_t event_ptid; - pid_t event_pid; - - if (debug_threads) - { - debug_printf ("HEW: Got exec event from LWP %ld\n", - lwpid_of (event_thr)); - } - - /* Get the event ptid. */ - event_ptid = ptid_of (event_thr); - event_pid = event_ptid.pid (); - - /* Save the syscall list from the execing process. */ - proc = get_thread_process (event_thr); - syscalls_to_catch = std::move (proc->syscalls_to_catch); - - /* Delete the execing process and all its threads. */ - linux_mourn (proc); - current_thread = NULL; - - /* Create a new process/lwp/thread. */ - proc = linux_add_process (event_pid, 0); - event_lwp = add_lwp (event_ptid); - event_thr = get_lwp_thread (event_lwp); - gdb_assert (current_thread == event_thr); - linux_arch_setup_thread (event_thr); - - /* Set the event status. */ - event_lwp->waitstatus.kind = TARGET_WAITKIND_EXECD; - event_lwp->waitstatus.value.execd_pathname - = xstrdup (linux_proc_pid_to_exec_file (lwpid_of (event_thr))); - - /* Mark the exec status as pending. */ - event_lwp->stopped = 1; - event_lwp->status_pending_p = 1; - event_lwp->status_pending = wstat; - event_thr->last_resume_kind = resume_continue; - event_thr->last_status.kind = TARGET_WAITKIND_IGNORE; - - /* Update syscall state in the new lwp, effectively mid-syscall too. */ - event_lwp->syscall_state = TARGET_WAITKIND_SYSCALL_ENTRY; - - /* Restore the list to catch. Don't rely on the client, which is free - to avoid sending a new list when the architecture doesn't change. - Also, for ANY_SYSCALL, the architecture doesn't really matter. */ - proc->syscalls_to_catch = std::move (syscalls_to_catch); - - /* Report the event. */ - *orig_event_lwp = event_lwp; - return 0; - } - - internal_error (__FILE__, __LINE__, _("unknown ptrace event %d"), event); -} - -/* Return the PC as read from the regcache of LWP, without any - adjustment. */ - -static CORE_ADDR -get_pc (struct lwp_info *lwp) -{ - struct thread_info *saved_thread; - struct regcache *regcache; - CORE_ADDR pc; - - if (the_low_target.get_pc == NULL) - return 0; - - saved_thread = current_thread; - current_thread = get_lwp_thread (lwp); - - regcache = get_thread_regcache (current_thread, 1); - pc = (*the_low_target.get_pc) (regcache); - - if (debug_threads) - debug_printf ("pc is 0x%lx\n", (long) pc); - - current_thread = saved_thread; - return pc; -} - -/* This function should only be called if LWP got a SYSCALL_SIGTRAP. - Fill *SYSNO with the syscall nr trapped. */ - -static void -get_syscall_trapinfo (struct lwp_info *lwp, int *sysno) -{ - struct thread_info *saved_thread; - struct regcache *regcache; - - if (the_low_target.get_syscall_trapinfo == NULL) - { - /* If we cannot get the syscall trapinfo, report an unknown - system call number. */ - *sysno = UNKNOWN_SYSCALL; - return; - } - - saved_thread = current_thread; - current_thread = get_lwp_thread (lwp); - - regcache = get_thread_regcache (current_thread, 1); - (*the_low_target.get_syscall_trapinfo) (regcache, sysno); - - if (debug_threads) - debug_printf ("get_syscall_trapinfo sysno %d\n", *sysno); - - current_thread = saved_thread; -} - -static int check_stopped_by_watchpoint (struct lwp_info *child); - -/* Called when the LWP stopped for a signal/trap. If it stopped for a - trap check what caused it (breakpoint, watchpoint, trace, etc.), - and save the result in the LWP's stop_reason field. If it stopped - for a breakpoint, decrement the PC if necessary on the lwp's - architecture. Returns true if we now have the LWP's stop PC. */ - -static int -save_stop_reason (struct lwp_info *lwp) -{ - CORE_ADDR pc; - CORE_ADDR sw_breakpoint_pc; - struct thread_info *saved_thread; -#if USE_SIGTRAP_SIGINFO - siginfo_t siginfo; -#endif - - if (the_low_target.get_pc == NULL) - return 0; - - pc = get_pc (lwp); - sw_breakpoint_pc = pc - the_low_target.decr_pc_after_break; - - /* breakpoint_at reads from the current thread. */ - saved_thread = current_thread; - current_thread = get_lwp_thread (lwp); - -#if USE_SIGTRAP_SIGINFO - if (ptrace (PTRACE_GETSIGINFO, lwpid_of (current_thread), - (PTRACE_TYPE_ARG3) 0, &siginfo) == 0) - { - if (siginfo.si_signo == SIGTRAP) - { - if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code) - && GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code)) - { - /* The si_code is ambiguous on this arch -- check debug - registers. */ - if (!check_stopped_by_watchpoint (lwp)) - lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT; - } - else if (GDB_ARCH_IS_TRAP_BRKPT (siginfo.si_code)) - { - /* If we determine the LWP stopped for a SW breakpoint, - trust it. Particularly don't check watchpoint - registers, because at least on s390, we'd find - stopped-by-watchpoint as long as there's a watchpoint - set. */ - lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT; - } - else if (GDB_ARCH_IS_TRAP_HWBKPT (siginfo.si_code)) - { - /* This can indicate either a hardware breakpoint or - hardware watchpoint. Check debug registers. */ - if (!check_stopped_by_watchpoint (lwp)) - lwp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT; - } - else if (siginfo.si_code == TRAP_TRACE) - { - /* We may have single stepped an instruction that - triggered a watchpoint. In that case, on some - architectures (such as x86), instead of TRAP_HWBKPT, - si_code indicates TRAP_TRACE, and we need to check - the debug registers separately. */ - if (!check_stopped_by_watchpoint (lwp)) - lwp->stop_reason = TARGET_STOPPED_BY_SINGLE_STEP; - } - } - } -#else - /* We may have just stepped a breakpoint instruction. E.g., in - non-stop mode, GDB first tells the thread A to step a range, and - then the user inserts a breakpoint inside the range. In that - case we need to report the breakpoint PC. */ - if ((!lwp->stepping || lwp->stop_pc == sw_breakpoint_pc) - && (*the_low_target.breakpoint_at) (sw_breakpoint_pc)) - lwp->stop_reason = TARGET_STOPPED_BY_SW_BREAKPOINT; - - if (hardware_breakpoint_inserted_here (pc)) - lwp->stop_reason = TARGET_STOPPED_BY_HW_BREAKPOINT; - - if (lwp->stop_reason == TARGET_STOPPED_BY_NO_REASON) - check_stopped_by_watchpoint (lwp); -#endif - - if (lwp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT) - { - if (debug_threads) - { - struct thread_info *thr = get_lwp_thread (lwp); - - debug_printf ("CSBB: %s stopped by software breakpoint\n", - target_pid_to_str (ptid_of (thr))); - } - - /* Back up the PC if necessary. */ - if (pc != sw_breakpoint_pc) - { - struct regcache *regcache - = get_thread_regcache (current_thread, 1); - (*the_low_target.set_pc) (regcache, sw_breakpoint_pc); - } - - /* Update this so we record the correct stop PC below. */ - pc = sw_breakpoint_pc; - } - else if (lwp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT) - { - if (debug_threads) - { - struct thread_info *thr = get_lwp_thread (lwp); - - debug_printf ("CSBB: %s stopped by hardware breakpoint\n", - target_pid_to_str (ptid_of (thr))); - } - } - else if (lwp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT) - { - if (debug_threads) - { - struct thread_info *thr = get_lwp_thread (lwp); - - debug_printf ("CSBB: %s stopped by hardware watchpoint\n", - target_pid_to_str (ptid_of (thr))); - } - } - else if (lwp->stop_reason == TARGET_STOPPED_BY_SINGLE_STEP) - { - if (debug_threads) - { - struct thread_info *thr = get_lwp_thread (lwp); - - debug_printf ("CSBB: %s stopped by trace\n", - target_pid_to_str (ptid_of (thr))); - } - } - - lwp->stop_pc = pc; - current_thread = saved_thread; - return 1; -} - -static struct lwp_info * -add_lwp (ptid_t ptid) -{ - struct lwp_info *lwp; - - lwp = XCNEW (struct lwp_info); - - lwp->waitstatus.kind = TARGET_WAITKIND_IGNORE; - - lwp->thread = add_thread (ptid, lwp); - - if (the_low_target.new_thread != NULL) - the_low_target.new_thread (lwp); - - return lwp; -} - -/* Callback to be used when calling fork_inferior, responsible for - actually initiating the tracing of the inferior. */ - -static void -linux_ptrace_fun () -{ - if (ptrace (PTRACE_TRACEME, 0, (PTRACE_TYPE_ARG3) 0, - (PTRACE_TYPE_ARG4) 0) < 0) - trace_start_error_with_name ("ptrace"); - - if (setpgid (0, 0) < 0) - trace_start_error_with_name ("setpgid"); - - /* If GDBserver is connected to gdb via stdio, redirect the inferior's - stdout to stderr so that inferior i/o doesn't corrupt the connection. - Also, redirect stdin to /dev/null. */ - if (remote_connection_is_stdio ()) - { - if (close (0) < 0) - trace_start_error_with_name ("close"); - if (open ("/dev/null", O_RDONLY) < 0) - trace_start_error_with_name ("open"); - if (dup2 (2, 1) < 0) - trace_start_error_with_name ("dup2"); - if (write (2, "stdin/stdout redirected\n", - sizeof ("stdin/stdout redirected\n") - 1) < 0) - { - /* Errors ignored. */; - } - } -} - -/* Start an inferior process and returns its pid. - PROGRAM is the name of the program to be started, and PROGRAM_ARGS - are its arguments. */ - -static int -linux_create_inferior (const char *program, - const std::vector<char *> &program_args) -{ - client_state &cs = get_client_state (); - struct lwp_info *new_lwp; - int pid; - ptid_t ptid; - - { - maybe_disable_address_space_randomization restore_personality - (cs.disable_randomization); - std::string str_program_args = stringify_argv (program_args); - - pid = fork_inferior (program, - str_program_args.c_str (), - get_environ ()->envp (), linux_ptrace_fun, - NULL, NULL, NULL, NULL); - } - - linux_add_process (pid, 0); - - ptid = ptid_t (pid, pid, 0); - new_lwp = add_lwp (ptid); - new_lwp->must_set_ptrace_flags = 1; - - post_fork_inferior (pid, program); - - return pid; -} - -/* Implement the post_create_inferior target_ops method. */ - -static void -linux_post_create_inferior (void) -{ - struct lwp_info *lwp = get_thread_lwp (current_thread); - - linux_arch_setup (); - - if (lwp->must_set_ptrace_flags) - { - struct process_info *proc = current_process (); - int options = linux_low_ptrace_options (proc->attached); - - linux_enable_event_reporting (lwpid_of (current_thread), options); - lwp->must_set_ptrace_flags = 0; - } -} - -/* Attach to an inferior process. Returns 0 on success, ERRNO on - error. */ - -int -linux_attach_lwp (ptid_t ptid) -{ - struct lwp_info *new_lwp; - int lwpid = ptid.lwp (); - - if (ptrace (PTRACE_ATTACH, lwpid, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0) - != 0) - return errno; - - new_lwp = add_lwp (ptid); - - /* We need to wait for SIGSTOP before being able to make the next - ptrace call on this LWP. */ - new_lwp->must_set_ptrace_flags = 1; - - if (linux_proc_pid_is_stopped (lwpid)) - { - if (debug_threads) - debug_printf ("Attached to a stopped process\n"); - - /* The process is definitely stopped. It is in a job control - stop, unless the kernel predates the TASK_STOPPED / - TASK_TRACED distinction, in which case it might be in a - ptrace stop. Make sure it is in a ptrace stop; from there we - can kill it, signal it, et cetera. - - First make sure there is a pending SIGSTOP. Since we are - already attached, the process can not transition from stopped - to running without a PTRACE_CONT; so we know this signal will - go into the queue. The SIGSTOP generated by PTRACE_ATTACH is - probably already in the queue (unless this kernel is old - enough to use TASK_STOPPED for ptrace stops); but since - SIGSTOP is not an RT signal, it can only be queued once. */ - kill_lwp (lwpid, SIGSTOP); - - /* Finally, resume the stopped process. This will deliver the - SIGSTOP (or a higher priority signal, just like normal - PTRACE_ATTACH), which we'll catch later on. */ - ptrace (PTRACE_CONT, lwpid, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0); - } - - /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH - brings it to a halt. - - There are several cases to consider here: - - 1) gdbserver has already attached to the process and is being notified - of a new thread that is being created. - In this case we should ignore that SIGSTOP and resume the - process. This is handled below by setting stop_expected = 1, - and the fact that add_thread sets last_resume_kind == - resume_continue. - - 2) This is the first thread (the process thread), and we're attaching - to it via attach_inferior. - In this case we want the process thread to stop. - This is handled by having linux_attach set last_resume_kind == - resume_stop after we return. - - If the pid we are attaching to is also the tgid, we attach to and - stop all the existing threads. Otherwise, we attach to pid and - ignore any other threads in the same group as this pid. - - 3) GDB is connecting to gdbserver and is requesting an enumeration of all - existing threads. - In this case we want the thread to stop. - FIXME: This case is currently not properly handled. - We should wait for the SIGSTOP but don't. Things work apparently - because enough time passes between when we ptrace (ATTACH) and when - gdb makes the next ptrace call on the thread. - - On the other hand, if we are currently trying to stop all threads, we - should treat the new thread as if we had sent it a SIGSTOP. This works - because we are guaranteed that the add_lwp call above added us to the - end of the list, and so the new thread has not yet reached - wait_for_sigstop (but will). */ - new_lwp->stop_expected = 1; - - return 0; -} - -/* Callback for linux_proc_attach_tgid_threads. Attach to PTID if not - already attached. Returns true if a new LWP is found, false - otherwise. */ - -static int -attach_proc_task_lwp_callback (ptid_t ptid) -{ - /* Is this a new thread? */ - if (find_thread_ptid (ptid) == NULL) - { - int lwpid = ptid.lwp (); - int err; - - if (debug_threads) - debug_printf ("Found new lwp %d\n", lwpid); - - err = linux_attach_lwp (ptid); - - /* Be quiet if we simply raced with the thread exiting. EPERM - is returned if the thread's task still exists, and is marked - as exited or zombie, as well as other conditions, so in that - case, confirm the status in /proc/PID/status. */ - if (err == ESRCH - || (err == EPERM && linux_proc_pid_is_gone (lwpid))) - { - if (debug_threads) - { - debug_printf ("Cannot attach to lwp %d: " - "thread is gone (%d: %s)\n", - lwpid, err, safe_strerror (err)); - } - } - else if (err != 0) - { - std::string reason - = linux_ptrace_attach_fail_reason_string (ptid, err); - - warning (_("Cannot attach to lwp %d: %s"), lwpid, reason.c_str ()); - } - - return 1; - } - return 0; -} - -static void async_file_mark (void); - -/* Attach to PID. If PID is the tgid, attach to it and all - of its threads. */ - -static int -linux_attach (unsigned long pid) -{ - struct process_info *proc; - struct thread_info *initial_thread; - ptid_t ptid = ptid_t (pid, pid, 0); - int err; - - proc = linux_add_process (pid, 1); - - /* Attach to PID. We will check for other threads - soon. */ - err = linux_attach_lwp (ptid); - if (err != 0) - { - remove_process (proc); - - std::string reason = linux_ptrace_attach_fail_reason_string (ptid, err); - error ("Cannot attach to process %ld: %s", pid, reason.c_str ()); - } - - /* Don't ignore the initial SIGSTOP if we just attached to this - process. It will be collected by wait shortly. */ - initial_thread = find_thread_ptid (ptid_t (pid, pid, 0)); - initial_thread->last_resume_kind = resume_stop; - - /* We must attach to every LWP. If /proc is mounted, use that to - find them now. On the one hand, the inferior may be using raw - clone instead of using pthreads. On the other hand, even if it - is using pthreads, GDB may not be connected yet (thread_db needs - to do symbol lookups, through qSymbol). Also, thread_db walks - structures in the inferior's address space to find the list of - threads/LWPs, and those structures may well be corrupted. Note - that once thread_db is loaded, we'll still use it to list threads - and associate pthread info with each LWP. */ - linux_proc_attach_tgid_threads (pid, attach_proc_task_lwp_callback); - - /* GDB will shortly read the xml target description for this - process, to figure out the process' architecture. But the target - description is only filled in when the first process/thread in - the thread group reports its initial PTRACE_ATTACH SIGSTOP. Do - that now, otherwise, if GDB is fast enough, it could read the - target description _before_ that initial stop. */ - if (non_stop) - { - struct lwp_info *lwp; - int wstat, lwpid; - ptid_t pid_ptid = ptid_t (pid); - - lwpid = linux_wait_for_event_filtered (pid_ptid, pid_ptid, - &wstat, __WALL); - gdb_assert (lwpid > 0); - - lwp = find_lwp_pid (ptid_t (lwpid)); - - if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGSTOP) - { - lwp->status_pending_p = 1; - lwp->status_pending = wstat; - } - - initial_thread->last_resume_kind = resume_continue; - - async_file_mark (); - - gdb_assert (proc->tdesc != NULL); - } - - return 0; -} - -static int -last_thread_of_process_p (int pid) -{ - bool seen_one = false; - - thread_info *thread = find_thread (pid, [&] (thread_info *thr_arg) - { - if (!seen_one) - { - /* This is the first thread of this process we see. */ - seen_one = true; - return false; - } - else - { - /* This is the second thread of this process we see. */ - return true; - } - }); - - return thread == NULL; -} - -/* Kill LWP. */ - -static void -linux_kill_one_lwp (struct lwp_info *lwp) -{ - struct thread_info *thr = get_lwp_thread (lwp); - int pid = lwpid_of (thr); - - /* PTRACE_KILL is unreliable. After stepping into a signal handler, - there is no signal context, and ptrace(PTRACE_KILL) (or - ptrace(PTRACE_CONT, SIGKILL), pretty much the same) acts like - ptrace(CONT, pid, 0,0) and just resumes the tracee. A better - alternative is to kill with SIGKILL. We only need one SIGKILL - per process, not one for each thread. But since we still support - support debugging programs using raw clone without CLONE_THREAD, - we send one for each thread. For years, we used PTRACE_KILL - only, so we're being a bit paranoid about some old kernels where - PTRACE_KILL might work better (dubious if there are any such, but - that's why it's paranoia), so we try SIGKILL first, PTRACE_KILL - second, and so we're fine everywhere. */ - - errno = 0; - kill_lwp (pid, SIGKILL); - if (debug_threads) - { - int save_errno = errno; - - debug_printf ("LKL: kill_lwp (SIGKILL) %s, 0, 0 (%s)\n", - target_pid_to_str (ptid_of (thr)), - save_errno ? safe_strerror (save_errno) : "OK"); - } - - errno = 0; - ptrace (PTRACE_KILL, pid, (PTRACE_TYPE_ARG3) 0, (PTRACE_TYPE_ARG4) 0); - if (debug_threads) - { - int save_errno = errno; - - debug_printf ("LKL: PTRACE_KILL %s, 0, 0 (%s)\n", - target_pid_to_str (ptid_of (thr)), - save_errno ? safe_strerror (save_errno) : "OK"); - } -} - -/* Kill LWP and wait for it to die. */ - -static void -kill_wait_lwp (struct lwp_info *lwp) -{ - struct thread_info *thr = get_lwp_thread (lwp); - int pid = ptid_of (thr).pid (); - int lwpid = ptid_of (thr).lwp (); - int wstat; - int res; - - if (debug_threads) - debug_printf ("kwl: killing lwp %d, for pid: %d\n", lwpid, pid); - - do - { - linux_kill_one_lwp (lwp); - - /* Make sure it died. Notes: - - - The loop is most likely unnecessary. - - - We don't use linux_wait_for_event as that could delete lwps - while we're iterating over them. We're not interested in - any pending status at this point, only in making sure all - wait status on the kernel side are collected until the - process is reaped. - - - We don't use __WALL here as the __WALL emulation relies on - SIGCHLD, and killing a stopped process doesn't generate - one, nor an exit status. - */ - res = my_waitpid (lwpid, &wstat, 0); - if (res == -1 && errno == ECHILD) - res = my_waitpid (lwpid, &wstat, __WCLONE); - } while (res > 0 && WIFSTOPPED (wstat)); - - /* Even if it was stopped, the child may have already disappeared. - E.g., if it was killed by SIGKILL. */ - if (res < 0 && errno != ECHILD) - perror_with_name ("kill_wait_lwp"); -} - -/* Callback for `for_each_thread'. Kills an lwp of a given process, - except the leader. */ - -static void -kill_one_lwp_callback (thread_info *thread, int pid) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - /* We avoid killing the first thread here, because of a Linux kernel (at - least 2.6.0-test7 through 2.6.8-rc4) bug; if we kill the parent before - the children get a chance to be reaped, it will remain a zombie - forever. */ - - if (lwpid_of (thread) == pid) - { - if (debug_threads) - debug_printf ("lkop: is last of process %s\n", - target_pid_to_str (thread->id)); - return; - } - - kill_wait_lwp (lwp); -} - -static int -linux_kill (process_info *process) -{ - int pid = process->pid; - - /* If we're killing a running inferior, make sure it is stopped - first, as PTRACE_KILL will not work otherwise. */ - stop_all_lwps (0, NULL); - - for_each_thread (pid, [&] (thread_info *thread) - { - kill_one_lwp_callback (thread, pid); - }); - - /* See the comment in linux_kill_one_lwp. We did not kill the first - thread in the list, so do so now. */ - lwp_info *lwp = find_lwp_pid (ptid_t (pid)); - - if (lwp == NULL) - { - if (debug_threads) - debug_printf ("lk_1: cannot find lwp for pid: %d\n", - pid); - } - else - kill_wait_lwp (lwp); - - the_target->mourn (process); - - /* Since we presently can only stop all lwps of all processes, we - need to unstop lwps of other processes. */ - unstop_all_lwps (0, NULL); - return 0; -} - -/* Get pending signal of THREAD, for detaching purposes. This is the - signal the thread last stopped for, which we need to deliver to the - thread when detaching, otherwise, it'd be suppressed/lost. */ - -static int -get_detach_signal (struct thread_info *thread) -{ - client_state &cs = get_client_state (); - enum gdb_signal signo = GDB_SIGNAL_0; - int status; - struct lwp_info *lp = get_thread_lwp (thread); - - if (lp->status_pending_p) - status = lp->status_pending; - else - { - /* If the thread had been suspended by gdbserver, and it stopped - cleanly, then it'll have stopped with SIGSTOP. But we don't - want to deliver that SIGSTOP. */ - if (thread->last_status.kind != TARGET_WAITKIND_STOPPED - || thread->last_status.value.sig == GDB_SIGNAL_0) - return 0; - - /* Otherwise, we may need to deliver the signal we - intercepted. */ - status = lp->last_status; - } - - if (!WIFSTOPPED (status)) - { - if (debug_threads) - debug_printf ("GPS: lwp %s hasn't stopped: no pending signal\n", - target_pid_to_str (ptid_of (thread))); - return 0; - } - - /* Extended wait statuses aren't real SIGTRAPs. */ - if (WSTOPSIG (status) == SIGTRAP && linux_is_extended_waitstatus (status)) - { - if (debug_threads) - debug_printf ("GPS: lwp %s had stopped with extended " - "status: no pending signal\n", - target_pid_to_str (ptid_of (thread))); - return 0; - } - - signo = gdb_signal_from_host (WSTOPSIG (status)); - - if (cs.program_signals_p && !cs.program_signals[signo]) - { - if (debug_threads) - debug_printf ("GPS: lwp %s had signal %s, but it is in nopass state\n", - target_pid_to_str (ptid_of (thread)), - gdb_signal_to_string (signo)); - return 0; - } - else if (!cs.program_signals_p - /* If we have no way to know which signals GDB does not - want to have passed to the program, assume - SIGTRAP/SIGINT, which is GDB's default. */ - && (signo == GDB_SIGNAL_TRAP || signo == GDB_SIGNAL_INT)) - { - if (debug_threads) - debug_printf ("GPS: lwp %s had signal %s, " - "but we don't know if we should pass it. " - "Default to not.\n", - target_pid_to_str (ptid_of (thread)), - gdb_signal_to_string (signo)); - return 0; - } - else - { - if (debug_threads) - debug_printf ("GPS: lwp %s has pending signal %s: delivering it.\n", - target_pid_to_str (ptid_of (thread)), - gdb_signal_to_string (signo)); - - return WSTOPSIG (status); - } -} - -/* Detach from LWP. */ - -static void -linux_detach_one_lwp (struct lwp_info *lwp) -{ - struct thread_info *thread = get_lwp_thread (lwp); - int sig; - int lwpid; - - /* If there is a pending SIGSTOP, get rid of it. */ - if (lwp->stop_expected) - { - if (debug_threads) - debug_printf ("Sending SIGCONT to %s\n", - target_pid_to_str (ptid_of (thread))); - - kill_lwp (lwpid_of (thread), SIGCONT); - lwp->stop_expected = 0; - } - - /* Pass on any pending signal for this thread. */ - sig = get_detach_signal (thread); - - /* Preparing to resume may try to write registers, and fail if the - lwp is zombie. If that happens, ignore the error. We'll handle - it below, when detach fails with ESRCH. */ - try - { - /* Flush any pending changes to the process's registers. */ - regcache_invalidate_thread (thread); - - /* Finally, let it resume. */ - if (the_low_target.prepare_to_resume != NULL) - the_low_target.prepare_to_resume (lwp); - } - catch (const gdb_exception_error &ex) - { - if (!check_ptrace_stopped_lwp_gone (lwp)) - throw; - } - - lwpid = lwpid_of (thread); - if (ptrace (PTRACE_DETACH, lwpid, (PTRACE_TYPE_ARG3) 0, - (PTRACE_TYPE_ARG4) (long) sig) < 0) - { - int save_errno = errno; - - /* We know the thread exists, so ESRCH must mean the lwp is - zombie. This can happen if one of the already-detached - threads exits the whole thread group. In that case we're - still attached, and must reap the lwp. */ - if (save_errno == ESRCH) - { - int ret, status; - - ret = my_waitpid (lwpid, &status, __WALL); - if (ret == -1) - { - warning (_("Couldn't reap LWP %d while detaching: %s"), - lwpid, safe_strerror (errno)); - } - else if (!WIFEXITED (status) && !WIFSIGNALED (status)) - { - warning (_("Reaping LWP %d while detaching " - "returned unexpected status 0x%x"), - lwpid, status); - } - } - else - { - error (_("Can't detach %s: %s"), - target_pid_to_str (ptid_of (thread)), - safe_strerror (save_errno)); - } - } - else if (debug_threads) - { - debug_printf ("PTRACE_DETACH (%s, %s, 0) (OK)\n", - target_pid_to_str (ptid_of (thread)), - strsignal (sig)); - } - - delete_lwp (lwp); -} - -/* Callback for for_each_thread. Detaches from non-leader threads of a - given process. */ - -static void -linux_detach_lwp_callback (thread_info *thread) -{ - /* We don't actually detach from the thread group leader just yet. - If the thread group exits, we must reap the zombie clone lwps - before we're able to reap the leader. */ - if (thread->id.pid () == thread->id.lwp ()) - return; - - lwp_info *lwp = get_thread_lwp (thread); - linux_detach_one_lwp (lwp); -} - -static int -linux_detach (process_info *process) -{ - struct lwp_info *main_lwp; - - /* As there's a step over already in progress, let it finish first, - otherwise nesting a stabilize_threads operation on top gets real - messy. */ - complete_ongoing_step_over (); - - /* Stop all threads before detaching. First, ptrace requires that - the thread is stopped to successfully detach. Second, thread_db - may need to uninstall thread event breakpoints from memory, which - only works with a stopped process anyway. */ - stop_all_lwps (0, NULL); - -#ifdef USE_THREAD_DB - thread_db_detach (process); -#endif - - /* Stabilize threads (move out of jump pads). */ - stabilize_threads (); - - /* Detach from the clone lwps first. If the thread group exits just - while we're detaching, we must reap the clone lwps before we're - able to reap the leader. */ - for_each_thread (process->pid, linux_detach_lwp_callback); - - main_lwp = find_lwp_pid (ptid_t (process->pid)); - linux_detach_one_lwp (main_lwp); - - the_target->mourn (process); - - /* Since we presently can only stop all lwps of all processes, we - need to unstop lwps of other processes. */ - unstop_all_lwps (0, NULL); - return 0; -} - -/* Remove all LWPs that belong to process PROC from the lwp list. */ - -static void -linux_mourn (struct process_info *process) -{ - struct process_info_private *priv; - -#ifdef USE_THREAD_DB - thread_db_mourn (process); -#endif - - for_each_thread (process->pid, [] (thread_info *thread) - { - delete_lwp (get_thread_lwp (thread)); - }); - - /* Freeing all private data. */ - priv = process->priv; - if (the_low_target.delete_process != NULL) - the_low_target.delete_process (priv->arch_private); - else - gdb_assert (priv->arch_private == NULL); - free (priv); - process->priv = NULL; - - remove_process (process); -} - -static void -linux_join (int pid) -{ - int status, ret; - - do { - ret = my_waitpid (pid, &status, 0); - if (WIFEXITED (status) || WIFSIGNALED (status)) - break; - } while (ret != -1 || errno != ECHILD); -} - -/* Return nonzero if the given thread is still alive. */ -static int -linux_thread_alive (ptid_t ptid) -{ - struct lwp_info *lwp = find_lwp_pid (ptid); - - /* We assume we always know if a thread exits. If a whole process - exited but we still haven't been able to report it to GDB, we'll - hold on to the last lwp of the dead process. */ - if (lwp != NULL) - return !lwp_is_marked_dead (lwp); - else - return 0; -} - -/* Return 1 if this lwp still has an interesting status pending. If - not (e.g., it had stopped for a breakpoint that is gone), return - false. */ - -static int -thread_still_has_status_pending_p (struct thread_info *thread) -{ - struct lwp_info *lp = get_thread_lwp (thread); - - if (!lp->status_pending_p) - return 0; - - if (thread->last_resume_kind != resume_stop - && (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT - || lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT)) - { - struct thread_info *saved_thread; - CORE_ADDR pc; - int discard = 0; - - gdb_assert (lp->last_status != 0); - - pc = get_pc (lp); - - saved_thread = current_thread; - current_thread = thread; - - if (pc != lp->stop_pc) - { - if (debug_threads) - debug_printf ("PC of %ld changed\n", - lwpid_of (thread)); - discard = 1; - } - -#if !USE_SIGTRAP_SIGINFO - else if (lp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT - && !(*the_low_target.breakpoint_at) (pc)) - { - if (debug_threads) - debug_printf ("previous SW breakpoint of %ld gone\n", - lwpid_of (thread)); - discard = 1; - } - else if (lp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT - && !hardware_breakpoint_inserted_here (pc)) - { - if (debug_threads) - debug_printf ("previous HW breakpoint of %ld gone\n", - lwpid_of (thread)); - discard = 1; - } -#endif - - current_thread = saved_thread; - - if (discard) - { - if (debug_threads) - debug_printf ("discarding pending breakpoint status\n"); - lp->status_pending_p = 0; - return 0; - } - } - - return 1; -} - -/* Returns true if LWP is resumed from the client's perspective. */ - -static int -lwp_resumed (struct lwp_info *lwp) -{ - struct thread_info *thread = get_lwp_thread (lwp); - - if (thread->last_resume_kind != resume_stop) - return 1; - - /* Did gdb send us a `vCont;t', but we haven't reported the - corresponding stop to gdb yet? If so, the thread is still - resumed/running from gdb's perspective. */ - if (thread->last_resume_kind == resume_stop - && thread->last_status.kind == TARGET_WAITKIND_IGNORE) - return 1; - - return 0; -} - -/* Return true if this lwp has an interesting status pending. */ -static bool -status_pending_p_callback (thread_info *thread, ptid_t ptid) -{ - struct lwp_info *lp = get_thread_lwp (thread); - - /* Check if we're only interested in events from a specific process - or a specific LWP. */ - if (!thread->id.matches (ptid)) - return 0; - - if (!lwp_resumed (lp)) - return 0; - - if (lp->status_pending_p - && !thread_still_has_status_pending_p (thread)) - { - linux_resume_one_lwp (lp, lp->stepping, GDB_SIGNAL_0, NULL); - return 0; - } - - return lp->status_pending_p; -} - -struct lwp_info * -find_lwp_pid (ptid_t ptid) -{ - thread_info *thread = find_thread ([&] (thread_info *thr_arg) - { - int lwp = ptid.lwp () != 0 ? ptid.lwp () : ptid.pid (); - return thr_arg->id.lwp () == lwp; - }); - - if (thread == NULL) - return NULL; - - return get_thread_lwp (thread); -} - -/* Return the number of known LWPs in the tgid given by PID. */ - -static int -num_lwps (int pid) -{ - int count = 0; - - for_each_thread (pid, [&] (thread_info *thread) - { - count++; - }); - - return count; -} - -/* See nat/linux-nat.h. */ - -struct lwp_info * -iterate_over_lwps (ptid_t filter, - gdb::function_view<iterate_over_lwps_ftype> callback) -{ - thread_info *thread = find_thread (filter, [&] (thread_info *thr_arg) - { - lwp_info *lwp = get_thread_lwp (thr_arg); - - return callback (lwp); - }); - - if (thread == NULL) - return NULL; - - return get_thread_lwp (thread); -} - -/* Detect zombie thread group leaders, and "exit" them. We can't reap - their exits until all other threads in the group have exited. */ - -static void -check_zombie_leaders (void) -{ - for_each_process ([] (process_info *proc) { - pid_t leader_pid = pid_of (proc); - struct lwp_info *leader_lp; - - leader_lp = find_lwp_pid (ptid_t (leader_pid)); - - if (debug_threads) - debug_printf ("leader_pid=%d, leader_lp!=NULL=%d, " - "num_lwps=%d, zombie=%d\n", - leader_pid, leader_lp!= NULL, num_lwps (leader_pid), - linux_proc_pid_is_zombie (leader_pid)); - - if (leader_lp != NULL && !leader_lp->stopped - /* Check if there are other threads in the group, as we may - have raced with the inferior simply exiting. */ - && !last_thread_of_process_p (leader_pid) - && linux_proc_pid_is_zombie (leader_pid)) - { - /* A leader zombie can mean one of two things: - - - It exited, and there's an exit status pending - available, or only the leader exited (not the whole - program). In the latter case, we can't waitpid the - leader's exit status until all other threads are gone. - - - There are 3 or more threads in the group, and a thread - other than the leader exec'd. On an exec, the Linux - kernel destroys all other threads (except the execing - one) in the thread group, and resets the execing thread's - tid to the tgid. No exit notification is sent for the - execing thread -- from the ptracer's perspective, it - appears as though the execing thread just vanishes. - Until we reap all other threads except the leader and the - execing thread, the leader will be zombie, and the - execing thread will be in `D (disc sleep)'. As soon as - all other threads are reaped, the execing thread changes - it's tid to the tgid, and the previous (zombie) leader - vanishes, giving place to the "new" leader. We could try - distinguishing the exit and exec cases, by waiting once - more, and seeing if something comes out, but it doesn't - sound useful. The previous leader _does_ go away, and - we'll re-add the new one once we see the exec event - (which is just the same as what would happen if the - previous leader did exit voluntarily before some other - thread execs). */ - - if (debug_threads) - debug_printf ("CZL: Thread group leader %d zombie " - "(it exited, or another thread execd).\n", - leader_pid); - - delete_lwp (leader_lp); - } - }); -} - -/* Callback for `find_thread'. Returns the first LWP that is not - stopped. */ - -static bool -not_stopped_callback (thread_info *thread, ptid_t filter) -{ - if (!thread->id.matches (filter)) - return false; - - lwp_info *lwp = get_thread_lwp (thread); - - return !lwp->stopped; -} - -/* Increment LWP's suspend count. */ - -static void -lwp_suspended_inc (struct lwp_info *lwp) -{ - lwp->suspended++; - - if (debug_threads && lwp->suspended > 4) - { - struct thread_info *thread = get_lwp_thread (lwp); - - debug_printf ("LWP %ld has a suspiciously high suspend count," - " suspended=%d\n", lwpid_of (thread), lwp->suspended); - } -} - -/* Decrement LWP's suspend count. */ - -static void -lwp_suspended_decr (struct lwp_info *lwp) -{ - lwp->suspended--; - - if (lwp->suspended < 0) - { - struct thread_info *thread = get_lwp_thread (lwp); - - internal_error (__FILE__, __LINE__, - "unsuspend LWP %ld, suspended=%d\n", lwpid_of (thread), - lwp->suspended); - } -} - -/* This function should only be called if the LWP got a SIGTRAP. - - Handle any tracepoint steps or hits. Return true if a tracepoint - event was handled, 0 otherwise. */ - -static int -handle_tracepoints (struct lwp_info *lwp) -{ - struct thread_info *tinfo = get_lwp_thread (lwp); - int tpoint_related_event = 0; - - gdb_assert (lwp->suspended == 0); - - /* If this tracepoint hit causes a tracing stop, we'll immediately - uninsert tracepoints. To do this, we temporarily pause all - threads, unpatch away, and then unpause threads. We need to make - sure the unpausing doesn't resume LWP too. */ - lwp_suspended_inc (lwp); - - /* And we need to be sure that any all-threads-stopping doesn't try - to move threads out of the jump pads, as it could deadlock the - inferior (LWP could be in the jump pad, maybe even holding the - lock.) */ - - /* Do any necessary step collect actions. */ - tpoint_related_event |= tracepoint_finished_step (tinfo, lwp->stop_pc); - - tpoint_related_event |= handle_tracepoint_bkpts (tinfo, lwp->stop_pc); - - /* See if we just hit a tracepoint and do its main collect - actions. */ - tpoint_related_event |= tracepoint_was_hit (tinfo, lwp->stop_pc); - - lwp_suspended_decr (lwp); - - gdb_assert (lwp->suspended == 0); - gdb_assert (!stabilizing_threads - || (lwp->collecting_fast_tracepoint - != fast_tpoint_collect_result::not_collecting)); - - if (tpoint_related_event) - { - if (debug_threads) - debug_printf ("got a tracepoint event\n"); - return 1; - } - - return 0; -} - -/* Convenience wrapper. Returns information about LWP's fast tracepoint - collection status. */ - -static fast_tpoint_collect_result -linux_fast_tracepoint_collecting (struct lwp_info *lwp, - struct fast_tpoint_collect_status *status) -{ - CORE_ADDR thread_area; - struct thread_info *thread = get_lwp_thread (lwp); - - if (the_low_target.get_thread_area == NULL) - return fast_tpoint_collect_result::not_collecting; - - /* Get the thread area address. This is used to recognize which - thread is which when tracing with the in-process agent library. - We don't read anything from the address, and treat it as opaque; - it's the address itself that we assume is unique per-thread. */ - if ((*the_low_target.get_thread_area) (lwpid_of (thread), &thread_area) == -1) - return fast_tpoint_collect_result::not_collecting; - - return fast_tracepoint_collecting (thread_area, lwp->stop_pc, status); -} - -/* The reason we resume in the caller, is because we want to be able - to pass lwp->status_pending as WSTAT, and we need to clear - status_pending_p before resuming, otherwise, linux_resume_one_lwp - refuses to resume. */ - -static int -maybe_move_out_of_jump_pad (struct lwp_info *lwp, int *wstat) -{ - struct thread_info *saved_thread; - - saved_thread = current_thread; - current_thread = get_lwp_thread (lwp); - - if ((wstat == NULL - || (WIFSTOPPED (*wstat) && WSTOPSIG (*wstat) != SIGTRAP)) - && supports_fast_tracepoints () - && agent_loaded_p ()) - { - struct fast_tpoint_collect_status status; - - if (debug_threads) - debug_printf ("Checking whether LWP %ld needs to move out of the " - "jump pad.\n", - lwpid_of (current_thread)); - - fast_tpoint_collect_result r - = linux_fast_tracepoint_collecting (lwp, &status); - - if (wstat == NULL - || (WSTOPSIG (*wstat) != SIGILL - && WSTOPSIG (*wstat) != SIGFPE - && WSTOPSIG (*wstat) != SIGSEGV - && WSTOPSIG (*wstat) != SIGBUS)) - { - lwp->collecting_fast_tracepoint = r; - - if (r != fast_tpoint_collect_result::not_collecting) - { - if (r == fast_tpoint_collect_result::before_insn - && lwp->exit_jump_pad_bkpt == NULL) - { - /* Haven't executed the original instruction yet. - Set breakpoint there, and wait till it's hit, - then single-step until exiting the jump pad. */ - lwp->exit_jump_pad_bkpt - = set_breakpoint_at (status.adjusted_insn_addr, NULL); - } - - if (debug_threads) - debug_printf ("Checking whether LWP %ld needs to move out of " - "the jump pad...it does\n", - lwpid_of (current_thread)); - current_thread = saved_thread; - - return 1; - } - } - else - { - /* If we get a synchronous signal while collecting, *and* - while executing the (relocated) original instruction, - reset the PC to point at the tpoint address, before - reporting to GDB. Otherwise, it's an IPA lib bug: just - report the signal to GDB, and pray for the best. */ - - lwp->collecting_fast_tracepoint - = fast_tpoint_collect_result::not_collecting; - - if (r != fast_tpoint_collect_result::not_collecting - && (status.adjusted_insn_addr <= lwp->stop_pc - && lwp->stop_pc < status.adjusted_insn_addr_end)) - { - siginfo_t info; - struct regcache *regcache; - - /* The si_addr on a few signals references the address - of the faulting instruction. Adjust that as - well. */ - if ((WSTOPSIG (*wstat) == SIGILL - || WSTOPSIG (*wstat) == SIGFPE - || WSTOPSIG (*wstat) == SIGBUS - || WSTOPSIG (*wstat) == SIGSEGV) - && ptrace (PTRACE_GETSIGINFO, lwpid_of (current_thread), - (PTRACE_TYPE_ARG3) 0, &info) == 0 - /* Final check just to make sure we don't clobber - the siginfo of non-kernel-sent signals. */ - && (uintptr_t) info.si_addr == lwp->stop_pc) - { - info.si_addr = (void *) (uintptr_t) status.tpoint_addr; - ptrace (PTRACE_SETSIGINFO, lwpid_of (current_thread), - (PTRACE_TYPE_ARG3) 0, &info); - } - - regcache = get_thread_regcache (current_thread, 1); - (*the_low_target.set_pc) (regcache, status.tpoint_addr); - lwp->stop_pc = status.tpoint_addr; - - /* Cancel any fast tracepoint lock this thread was - holding. */ - force_unlock_trace_buffer (); - } - - if (lwp->exit_jump_pad_bkpt != NULL) - { - if (debug_threads) - debug_printf ("Cancelling fast exit-jump-pad: removing bkpt. " - "stopping all threads momentarily.\n"); - - stop_all_lwps (1, lwp); - - delete_breakpoint (lwp->exit_jump_pad_bkpt); - lwp->exit_jump_pad_bkpt = NULL; - - unstop_all_lwps (1, lwp); - - gdb_assert (lwp->suspended >= 0); - } - } - } - - if (debug_threads) - debug_printf ("Checking whether LWP %ld needs to move out of the " - "jump pad...no\n", - lwpid_of (current_thread)); - - current_thread = saved_thread; - return 0; -} - -/* Enqueue one signal in the "signals to report later when out of the - jump pad" list. */ - -static void -enqueue_one_deferred_signal (struct lwp_info *lwp, int *wstat) -{ - struct pending_signals *p_sig; - struct thread_info *thread = get_lwp_thread (lwp); - - if (debug_threads) - debug_printf ("Deferring signal %d for LWP %ld.\n", - WSTOPSIG (*wstat), lwpid_of (thread)); - - if (debug_threads) - { - struct pending_signals *sig; - - for (sig = lwp->pending_signals_to_report; - sig != NULL; - sig = sig->prev) - debug_printf (" Already queued %d\n", - sig->signal); - - debug_printf (" (no more currently queued signals)\n"); - } - - /* Don't enqueue non-RT signals if they are already in the deferred - queue. (SIGSTOP being the easiest signal to see ending up here - twice) */ - if (WSTOPSIG (*wstat) < __SIGRTMIN) - { - struct pending_signals *sig; - - for (sig = lwp->pending_signals_to_report; - sig != NULL; - sig = sig->prev) - { - if (sig->signal == WSTOPSIG (*wstat)) - { - if (debug_threads) - debug_printf ("Not requeuing already queued non-RT signal %d" - " for LWP %ld\n", - sig->signal, - lwpid_of (thread)); - return; - } - } - } - - p_sig = XCNEW (struct pending_signals); - p_sig->prev = lwp->pending_signals_to_report; - p_sig->signal = WSTOPSIG (*wstat); - - ptrace (PTRACE_GETSIGINFO, lwpid_of (thread), (PTRACE_TYPE_ARG3) 0, - &p_sig->info); - - lwp->pending_signals_to_report = p_sig; -} - -/* Dequeue one signal from the "signals to report later when out of - the jump pad" list. */ - -static int -dequeue_one_deferred_signal (struct lwp_info *lwp, int *wstat) -{ - struct thread_info *thread = get_lwp_thread (lwp); - - if (lwp->pending_signals_to_report != NULL) - { - struct pending_signals **p_sig; - - p_sig = &lwp->pending_signals_to_report; - while ((*p_sig)->prev != NULL) - p_sig = &(*p_sig)->prev; - - *wstat = W_STOPCODE ((*p_sig)->signal); - if ((*p_sig)->info.si_signo != 0) - ptrace (PTRACE_SETSIGINFO, lwpid_of (thread), (PTRACE_TYPE_ARG3) 0, - &(*p_sig)->info); - free (*p_sig); - *p_sig = NULL; - - if (debug_threads) - debug_printf ("Reporting deferred signal %d for LWP %ld.\n", - WSTOPSIG (*wstat), lwpid_of (thread)); - - if (debug_threads) - { - struct pending_signals *sig; - - for (sig = lwp->pending_signals_to_report; - sig != NULL; - sig = sig->prev) - debug_printf (" Still queued %d\n", - sig->signal); - - debug_printf (" (no more queued signals)\n"); - } - - return 1; - } - - return 0; -} - -/* Fetch the possibly triggered data watchpoint info and store it in - CHILD. - - On some archs, like x86, that use debug registers to set - watchpoints, it's possible that the way to know which watched - address trapped, is to check the register that is used to select - which address to watch. Problem is, between setting the watchpoint - and reading back which data address trapped, the user may change - the set of watchpoints, and, as a consequence, GDB changes the - debug registers in the inferior. To avoid reading back a stale - stopped-data-address when that happens, we cache in LP the fact - that a watchpoint trapped, and the corresponding data address, as - soon as we see CHILD stop with a SIGTRAP. If GDB changes the debug - registers meanwhile, we have the cached data we can rely on. */ - -static int -check_stopped_by_watchpoint (struct lwp_info *child) -{ - if (the_low_target.stopped_by_watchpoint != NULL) - { - struct thread_info *saved_thread; - - saved_thread = current_thread; - current_thread = get_lwp_thread (child); - - if (the_low_target.stopped_by_watchpoint ()) - { - child->stop_reason = TARGET_STOPPED_BY_WATCHPOINT; - - if (the_low_target.stopped_data_address != NULL) - child->stopped_data_address - = the_low_target.stopped_data_address (); - else - child->stopped_data_address = 0; - } - - current_thread = saved_thread; - } - - return child->stop_reason == TARGET_STOPPED_BY_WATCHPOINT; -} - -/* Return the ptrace options that we want to try to enable. */ - -static int -linux_low_ptrace_options (int attached) -{ - client_state &cs = get_client_state (); - int options = 0; - - if (!attached) - options |= PTRACE_O_EXITKILL; - - if (cs.report_fork_events) - options |= PTRACE_O_TRACEFORK; - - if (cs.report_vfork_events) - options |= (PTRACE_O_TRACEVFORK | PTRACE_O_TRACEVFORKDONE); - - if (cs.report_exec_events) - options |= PTRACE_O_TRACEEXEC; - - options |= PTRACE_O_TRACESYSGOOD; - - return options; -} - -/* Do low-level handling of the event, and check if we should go on - and pass it to caller code. Return the affected lwp if we are, or - NULL otherwise. */ - -static struct lwp_info * -linux_low_filter_event (int lwpid, int wstat) -{ - client_state &cs = get_client_state (); - struct lwp_info *child; - struct thread_info *thread; - int have_stop_pc = 0; - - child = find_lwp_pid (ptid_t (lwpid)); - - /* Check for stop events reported by a process we didn't already - know about - anything not already in our LWP list. - - If we're expecting to receive stopped processes after - fork, vfork, and clone events, then we'll just add the - new one to our list and go back to waiting for the event - to be reported - the stopped process might be returned - from waitpid before or after the event is. - - But note the case of a non-leader thread exec'ing after the - leader having exited, and gone from our lists (because - check_zombie_leaders deleted it). The non-leader thread - changes its tid to the tgid. */ - - if (WIFSTOPPED (wstat) && child == NULL && WSTOPSIG (wstat) == SIGTRAP - && linux_ptrace_get_extended_event (wstat) == PTRACE_EVENT_EXEC) - { - ptid_t child_ptid; - - /* A multi-thread exec after we had seen the leader exiting. */ - if (debug_threads) - { - debug_printf ("LLW: Re-adding thread group leader LWP %d" - "after exec.\n", lwpid); - } - - child_ptid = ptid_t (lwpid, lwpid, 0); - child = add_lwp (child_ptid); - child->stopped = 1; - current_thread = child->thread; - } - - /* If we didn't find a process, one of two things presumably happened: - - A process we started and then detached from has exited. Ignore it. - - A process we are controlling has forked and the new child's stop - was reported to us by the kernel. Save its PID. */ - if (child == NULL && WIFSTOPPED (wstat)) - { - add_to_pid_list (&stopped_pids, lwpid, wstat); - return NULL; - } - else if (child == NULL) - return NULL; - - thread = get_lwp_thread (child); - - child->stopped = 1; - - child->last_status = wstat; - - /* Check if the thread has exited. */ - if ((WIFEXITED (wstat) || WIFSIGNALED (wstat))) - { - if (debug_threads) - debug_printf ("LLFE: %d exited.\n", lwpid); - - if (finish_step_over (child)) - { - /* Unsuspend all other LWPs, and set them back running again. */ - unsuspend_all_lwps (child); - } - - /* If there is at least one more LWP, then the exit signal was - not the end of the debugged application and should be - ignored, unless GDB wants to hear about thread exits. */ - if (cs.report_thread_events - || last_thread_of_process_p (pid_of (thread))) - { - /* Since events are serialized to GDB core, and we can't - report this one right now. Leave the status pending for - the next time we're able to report it. */ - mark_lwp_dead (child, wstat); - return child; - } - else - { - delete_lwp (child); - return NULL; - } - } - - gdb_assert (WIFSTOPPED (wstat)); - - if (WIFSTOPPED (wstat)) - { - struct process_info *proc; - - /* Architecture-specific setup after inferior is running. */ - proc = find_process_pid (pid_of (thread)); - if (proc->tdesc == NULL) - { - if (proc->attached) - { - /* This needs to happen after we have attached to the - inferior and it is stopped for the first time, but - before we access any inferior registers. */ - linux_arch_setup_thread (thread); - } - else - { - /* The process is started, but GDBserver will do - architecture-specific setup after the program stops at - the first instruction. */ - child->status_pending_p = 1; - child->status_pending = wstat; - return child; - } - } - } - - if (WIFSTOPPED (wstat) && child->must_set_ptrace_flags) - { - struct process_info *proc = find_process_pid (pid_of (thread)); - int options = linux_low_ptrace_options (proc->attached); - - linux_enable_event_reporting (lwpid, options); - child->must_set_ptrace_flags = 0; - } - - /* Always update syscall_state, even if it will be filtered later. */ - if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SYSCALL_SIGTRAP) - { - child->syscall_state - = (child->syscall_state == TARGET_WAITKIND_SYSCALL_ENTRY - ? TARGET_WAITKIND_SYSCALL_RETURN - : TARGET_WAITKIND_SYSCALL_ENTRY); - } - else - { - /* Almost all other ptrace-stops are known to be outside of system - calls, with further exceptions in handle_extended_wait. */ - child->syscall_state = TARGET_WAITKIND_IGNORE; - } - - /* Be careful to not overwrite stop_pc until save_stop_reason is - called. */ - if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGTRAP - && linux_is_extended_waitstatus (wstat)) - { - child->stop_pc = get_pc (child); - if (handle_extended_wait (&child, wstat)) - { - /* The event has been handled, so just return without - reporting it. */ - return NULL; - } - } - - if (linux_wstatus_maybe_breakpoint (wstat)) - { - if (save_stop_reason (child)) - have_stop_pc = 1; - } - - if (!have_stop_pc) - child->stop_pc = get_pc (child); - - if (WIFSTOPPED (wstat) && WSTOPSIG (wstat) == SIGSTOP - && child->stop_expected) - { - if (debug_threads) - debug_printf ("Expected stop.\n"); - child->stop_expected = 0; - - if (thread->last_resume_kind == resume_stop) - { - /* We want to report the stop to the core. Treat the - SIGSTOP as a normal event. */ - if (debug_threads) - debug_printf ("LLW: resume_stop SIGSTOP caught for %s.\n", - target_pid_to_str (ptid_of (thread))); - } - else if (stopping_threads != NOT_STOPPING_THREADS) - { - /* Stopping threads. We don't want this SIGSTOP to end up - pending. */ - if (debug_threads) - debug_printf ("LLW: SIGSTOP caught for %s " - "while stopping threads.\n", - target_pid_to_str (ptid_of (thread))); - return NULL; - } - else - { - /* This is a delayed SIGSTOP. Filter out the event. */ - if (debug_threads) - debug_printf ("LLW: %s %s, 0, 0 (discard delayed SIGSTOP)\n", - child->stepping ? "step" : "continue", - target_pid_to_str (ptid_of (thread))); - - linux_resume_one_lwp (child, child->stepping, 0, NULL); - return NULL; - } - } - - child->status_pending_p = 1; - child->status_pending = wstat; - return child; -} - -/* Return true if THREAD is doing hardware single step. */ - -static int -maybe_hw_step (struct thread_info *thread) -{ - if (can_hardware_single_step ()) - return 1; - else - { - /* GDBserver must insert single-step breakpoint for software - single step. */ - gdb_assert (has_single_step_breakpoints (thread)); - return 0; - } -} - -/* Resume LWPs that are currently stopped without any pending status - to report, but are resumed from the core's perspective. */ - -static void -resume_stopped_resumed_lwps (thread_info *thread) -{ - struct lwp_info *lp = get_thread_lwp (thread); - - if (lp->stopped - && !lp->suspended - && !lp->status_pending_p - && thread->last_status.kind == TARGET_WAITKIND_IGNORE) - { - int step = 0; - - if (thread->last_resume_kind == resume_step) - step = maybe_hw_step (thread); - - if (debug_threads) - debug_printf ("RSRL: resuming stopped-resumed LWP %s at %s: step=%d\n", - target_pid_to_str (ptid_of (thread)), - paddress (lp->stop_pc), - step); - - linux_resume_one_lwp (lp, step, GDB_SIGNAL_0, NULL); - } -} - -/* Wait for an event from child(ren) WAIT_PTID, and return any that - match FILTER_PTID (leaving others pending). The PTIDs can be: - minus_one_ptid, to specify any child; a pid PTID, specifying all - lwps of a thread group; or a PTID representing a single lwp. Store - the stop status through the status pointer WSTAT. OPTIONS is - passed to the waitpid call. Return 0 if no event was found and - OPTIONS contains WNOHANG. Return -1 if no unwaited-for children - was found. Return the PID of the stopped child otherwise. */ - -static int -linux_wait_for_event_filtered (ptid_t wait_ptid, ptid_t filter_ptid, - int *wstatp, int options) -{ - struct thread_info *event_thread; - struct lwp_info *event_child, *requested_child; - sigset_t block_mask, prev_mask; - - retry: - /* N.B. event_thread points to the thread_info struct that contains - event_child. Keep them in sync. */ - event_thread = NULL; - event_child = NULL; - requested_child = NULL; - - /* Check for a lwp with a pending status. */ - - if (filter_ptid == minus_one_ptid || filter_ptid.is_pid ()) - { - event_thread = find_thread_in_random ([&] (thread_info *thread) - { - return status_pending_p_callback (thread, filter_ptid); - }); - - if (event_thread != NULL) - event_child = get_thread_lwp (event_thread); - if (debug_threads && event_thread) - debug_printf ("Got a pending child %ld\n", lwpid_of (event_thread)); - } - else if (filter_ptid != null_ptid) - { - requested_child = find_lwp_pid (filter_ptid); - - if (stopping_threads == NOT_STOPPING_THREADS - && requested_child->status_pending_p - && (requested_child->collecting_fast_tracepoint - != fast_tpoint_collect_result::not_collecting)) - { - enqueue_one_deferred_signal (requested_child, - &requested_child->status_pending); - requested_child->status_pending_p = 0; - requested_child->status_pending = 0; - linux_resume_one_lwp (requested_child, 0, 0, NULL); - } - - if (requested_child->suspended - && requested_child->status_pending_p) - { - internal_error (__FILE__, __LINE__, - "requesting an event out of a" - " suspended child?"); - } - - if (requested_child->status_pending_p) - { - event_child = requested_child; - event_thread = get_lwp_thread (event_child); - } - } - - if (event_child != NULL) - { - if (debug_threads) - debug_printf ("Got an event from pending child %ld (%04x)\n", - lwpid_of (event_thread), event_child->status_pending); - *wstatp = event_child->status_pending; - event_child->status_pending_p = 0; - event_child->status_pending = 0; - current_thread = event_thread; - return lwpid_of (event_thread); - } - - /* But if we don't find a pending event, we'll have to wait. - - We only enter this loop if no process has a pending wait status. - Thus any action taken in response to a wait status inside this - loop is responding as soon as we detect the status, not after any - pending events. */ - - /* Make sure SIGCHLD is blocked until the sigsuspend below. Block - all signals while here. */ - sigfillset (&block_mask); - gdb_sigmask (SIG_BLOCK, &block_mask, &prev_mask); - - /* Always pull all events out of the kernel. We'll randomly select - an event LWP out of all that have events, to prevent - starvation. */ - while (event_child == NULL) - { - pid_t ret = 0; - - /* Always use -1 and WNOHANG, due to couple of a kernel/ptrace - quirks: - - - If the thread group leader exits while other threads in the - thread group still exist, waitpid(TGID, ...) hangs. That - waitpid won't return an exit status until the other threads - in the group are reaped. - - - When a non-leader thread execs, that thread just vanishes - without reporting an exit (so we'd hang if we waited for it - explicitly in that case). The exec event is reported to - the TGID pid. */ - errno = 0; - ret = my_waitpid (-1, wstatp, options | WNOHANG); - - if (debug_threads) - debug_printf ("LWFE: waitpid(-1, ...) returned %d, %s\n", - ret, errno ? safe_strerror (errno) : "ERRNO-OK"); - - if (ret > 0) - { - if (debug_threads) - { - debug_printf ("LLW: waitpid %ld received %s\n", - (long) ret, status_to_str (*wstatp)); - } - - /* Filter all events. IOW, leave all events pending. We'll - randomly select an event LWP out of all that have events - below. */ - linux_low_filter_event (ret, *wstatp); - /* Retry until nothing comes out of waitpid. A single - SIGCHLD can indicate more than one child stopped. */ - continue; - } - - /* Now that we've pulled all events out of the kernel, resume - LWPs that don't have an interesting event to report. */ - if (stopping_threads == NOT_STOPPING_THREADS) - for_each_thread (resume_stopped_resumed_lwps); - - /* ... and find an LWP with a status to report to the core, if - any. */ - event_thread = find_thread_in_random ([&] (thread_info *thread) - { - return status_pending_p_callback (thread, filter_ptid); - }); - - if (event_thread != NULL) - { - event_child = get_thread_lwp (event_thread); - *wstatp = event_child->status_pending; - event_child->status_pending_p = 0; - event_child->status_pending = 0; - break; - } - - /* Check for zombie thread group leaders. Those can't be reaped - until all other threads in the thread group are. */ - check_zombie_leaders (); - - auto not_stopped = [&] (thread_info *thread) - { - return not_stopped_callback (thread, wait_ptid); - }; - - /* If there are no resumed children left in the set of LWPs we - want to wait for, bail. We can't just block in - waitpid/sigsuspend, because lwps might have been left stopped - in trace-stop state, and we'd be stuck forever waiting for - their status to change (which would only happen if we resumed - them). Even if WNOHANG is set, this return code is preferred - over 0 (below), as it is more detailed. */ - if (find_thread (not_stopped) == NULL) - { - if (debug_threads) - debug_printf ("LLW: exit (no unwaited-for LWP)\n"); - gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); - return -1; - } - - /* No interesting event to report to the caller. */ - if ((options & WNOHANG)) - { - if (debug_threads) - debug_printf ("WNOHANG set, no event found\n"); - - gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); - return 0; - } - - /* Block until we get an event reported with SIGCHLD. */ - if (debug_threads) - debug_printf ("sigsuspend'ing\n"); - - sigsuspend (&prev_mask); - gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); - goto retry; - } - - gdb_sigmask (SIG_SETMASK, &prev_mask, NULL); - - current_thread = event_thread; - - return lwpid_of (event_thread); -} - -/* Wait for an event from child(ren) PTID. PTIDs can be: - minus_one_ptid, to specify any child; a pid PTID, specifying all - lwps of a thread group; or a PTID representing a single lwp. Store - the stop status through the status pointer WSTAT. OPTIONS is - passed to the waitpid call. Return 0 if no event was found and - OPTIONS contains WNOHANG. Return -1 if no unwaited-for children - was found. Return the PID of the stopped child otherwise. */ - -static int -linux_wait_for_event (ptid_t ptid, int *wstatp, int options) -{ - return linux_wait_for_event_filtered (ptid, ptid, wstatp, options); -} - -/* Select one LWP out of those that have events pending. */ - -static void -select_event_lwp (struct lwp_info **orig_lp) -{ - struct thread_info *event_thread = NULL; - - /* In all-stop, give preference to the LWP that is being - single-stepped. There will be at most one, and it's the LWP that - the core is most interested in. If we didn't do this, then we'd - have to handle pending step SIGTRAPs somehow in case the core - later continues the previously-stepped thread, otherwise we'd - report the pending SIGTRAP, and the core, not having stepped the - thread, wouldn't understand what the trap was for, and therefore - would report it to the user as a random signal. */ - if (!non_stop) - { - event_thread = find_thread ([] (thread_info *thread) - { - lwp_info *lp = get_thread_lwp (thread); - - return (thread->last_status.kind == TARGET_WAITKIND_IGNORE - && thread->last_resume_kind == resume_step - && lp->status_pending_p); - }); - - if (event_thread != NULL) - { - if (debug_threads) - debug_printf ("SEL: Select single-step %s\n", - target_pid_to_str (ptid_of (event_thread))); - } - } - if (event_thread == NULL) - { - /* No single-stepping LWP. Select one at random, out of those - which have had events. */ - - event_thread = find_thread_in_random ([&] (thread_info *thread) - { - lwp_info *lp = get_thread_lwp (thread); - - /* Only resumed LWPs that have an event pending. */ - return (thread->last_status.kind == TARGET_WAITKIND_IGNORE - && lp->status_pending_p); - }); - } - - if (event_thread != NULL) - { - struct lwp_info *event_lp = get_thread_lwp (event_thread); - - /* Switch the event LWP. */ - *orig_lp = event_lp; - } -} - -/* Decrement the suspend count of all LWPs, except EXCEPT, if non - NULL. */ - -static void -unsuspend_all_lwps (struct lwp_info *except) -{ - for_each_thread ([&] (thread_info *thread) - { - lwp_info *lwp = get_thread_lwp (thread); - - if (lwp != except) - lwp_suspended_decr (lwp); - }); -} - -static void move_out_of_jump_pad_callback (thread_info *thread); -static bool stuck_in_jump_pad_callback (thread_info *thread); -static bool lwp_running (thread_info *thread); -static ptid_t linux_wait_1 (ptid_t ptid, - struct target_waitstatus *ourstatus, - int target_options); - -/* Stabilize threads (move out of jump pads). - - If a thread is midway collecting a fast tracepoint, we need to - finish the collection and move it out of the jump pad before - reporting the signal. - - This avoids recursion while collecting (when a signal arrives - midway, and the signal handler itself collects), which would trash - the trace buffer. In case the user set a breakpoint in a signal - handler, this avoids the backtrace showing the jump pad, etc.. - Most importantly, there are certain things we can't do safely if - threads are stopped in a jump pad (or in its callee's). For - example: - - - starting a new trace run. A thread still collecting the - previous run, could trash the trace buffer when resumed. The trace - buffer control structures would have been reset but the thread had - no way to tell. The thread could even midway memcpy'ing to the - buffer, which would mean that when resumed, it would clobber the - trace buffer that had been set for a new run. - - - we can't rewrite/reuse the jump pads for new tracepoints - safely. Say you do tstart while a thread is stopped midway while - collecting. When the thread is later resumed, it finishes the - collection, and returns to the jump pad, to execute the original - instruction that was under the tracepoint jump at the time the - older run had been started. If the jump pad had been rewritten - since for something else in the new run, the thread would now - execute the wrong / random instructions. */ - -static void -linux_stabilize_threads (void) -{ - thread_info *thread_stuck = find_thread (stuck_in_jump_pad_callback); - - if (thread_stuck != NULL) - { - if (debug_threads) - debug_printf ("can't stabilize, LWP %ld is stuck in jump pad\n", - lwpid_of (thread_stuck)); - return; - } - - thread_info *saved_thread = current_thread; - - stabilizing_threads = 1; - - /* Kick 'em all. */ - for_each_thread (move_out_of_jump_pad_callback); - - /* Loop until all are stopped out of the jump pads. */ - while (find_thread (lwp_running) != NULL) - { - struct target_waitstatus ourstatus; - struct lwp_info *lwp; - int wstat; - - /* Note that we go through the full wait even loop. While - moving threads out of jump pad, we need to be able to step - over internal breakpoints and such. */ - linux_wait_1 (minus_one_ptid, &ourstatus, 0); - - if (ourstatus.kind == TARGET_WAITKIND_STOPPED) - { - lwp = get_thread_lwp (current_thread); - - /* Lock it. */ - lwp_suspended_inc (lwp); - - if (ourstatus.value.sig != GDB_SIGNAL_0 - || current_thread->last_resume_kind == resume_stop) - { - wstat = W_STOPCODE (gdb_signal_to_host (ourstatus.value.sig)); - enqueue_one_deferred_signal (lwp, &wstat); - } - } - } - - unsuspend_all_lwps (NULL); - - stabilizing_threads = 0; - - current_thread = saved_thread; - - if (debug_threads) - { - thread_stuck = find_thread (stuck_in_jump_pad_callback); - - if (thread_stuck != NULL) - debug_printf ("couldn't stabilize, LWP %ld got stuck in jump pad\n", - lwpid_of (thread_stuck)); - } -} - -/* Convenience function that is called when the kernel reports an - event that is not passed out to GDB. */ - -static ptid_t -ignore_event (struct target_waitstatus *ourstatus) -{ - /* If we got an event, there may still be others, as a single - SIGCHLD can indicate more than one child stopped. This forces - another target_wait call. */ - async_file_mark (); - - ourstatus->kind = TARGET_WAITKIND_IGNORE; - return null_ptid; -} - -/* Convenience function that is called when the kernel reports an exit - event. This decides whether to report the event to GDB as a - process exit event, a thread exit event, or to suppress the - event. */ - -static ptid_t -filter_exit_event (struct lwp_info *event_child, - struct target_waitstatus *ourstatus) -{ - client_state &cs = get_client_state (); - struct thread_info *thread = get_lwp_thread (event_child); - ptid_t ptid = ptid_of (thread); - - if (!last_thread_of_process_p (pid_of (thread))) - { - if (cs.report_thread_events) - ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED; - else - ourstatus->kind = TARGET_WAITKIND_IGNORE; - - delete_lwp (event_child); - } - return ptid; -} - -/* Returns 1 if GDB is interested in any event_child syscalls. */ - -static int -gdb_catching_syscalls_p (struct lwp_info *event_child) -{ - struct thread_info *thread = get_lwp_thread (event_child); - struct process_info *proc = get_thread_process (thread); - - return !proc->syscalls_to_catch.empty (); -} - -/* Returns 1 if GDB is interested in the event_child syscall. - Only to be called when stopped reason is SYSCALL_SIGTRAP. */ - -static int -gdb_catch_this_syscall_p (struct lwp_info *event_child) -{ - int sysno; - struct thread_info *thread = get_lwp_thread (event_child); - struct process_info *proc = get_thread_process (thread); - - if (proc->syscalls_to_catch.empty ()) - return 0; - - if (proc->syscalls_to_catch[0] == ANY_SYSCALL) - return 1; - - get_syscall_trapinfo (event_child, &sysno); - - for (int iter : proc->syscalls_to_catch) - if (iter == sysno) - return 1; - - return 0; -} - -/* Wait for process, returns status. */ - -static ptid_t -linux_wait_1 (ptid_t ptid, - struct target_waitstatus *ourstatus, int target_options) -{ - client_state &cs = get_client_state (); - int w; - struct lwp_info *event_child; - int options; - int pid; - int step_over_finished; - int bp_explains_trap; - int maybe_internal_trap; - int report_to_gdb; - int trace_event; - int in_step_range; - int any_resumed; - - if (debug_threads) - { - debug_enter (); - debug_printf ("linux_wait_1: [%s]\n", target_pid_to_str (ptid)); - } - - /* Translate generic target options into linux options. */ - options = __WALL; - if (target_options & TARGET_WNOHANG) - options |= WNOHANG; - - bp_explains_trap = 0; - trace_event = 0; - in_step_range = 0; - ourstatus->kind = TARGET_WAITKIND_IGNORE; - - auto status_pending_p_any = [&] (thread_info *thread) - { - return status_pending_p_callback (thread, minus_one_ptid); - }; - - auto not_stopped = [&] (thread_info *thread) - { - return not_stopped_callback (thread, minus_one_ptid); - }; - - /* Find a resumed LWP, if any. */ - if (find_thread (status_pending_p_any) != NULL) - any_resumed = 1; - else if (find_thread (not_stopped) != NULL) - any_resumed = 1; - else - any_resumed = 0; - - if (step_over_bkpt == null_ptid) - pid = linux_wait_for_event (ptid, &w, options); - else - { - if (debug_threads) - debug_printf ("step_over_bkpt set [%s], doing a blocking wait\n", - target_pid_to_str (step_over_bkpt)); - pid = linux_wait_for_event (step_over_bkpt, &w, options & ~WNOHANG); - } - - if (pid == 0 || (pid == -1 && !any_resumed)) - { - gdb_assert (target_options & TARGET_WNOHANG); - - if (debug_threads) - { - debug_printf ("linux_wait_1 ret = null_ptid, " - "TARGET_WAITKIND_IGNORE\n"); - debug_exit (); - } - - ourstatus->kind = TARGET_WAITKIND_IGNORE; - return null_ptid; - } - else if (pid == -1) - { - if (debug_threads) - { - debug_printf ("linux_wait_1 ret = null_ptid, " - "TARGET_WAITKIND_NO_RESUMED\n"); - debug_exit (); - } - - ourstatus->kind = TARGET_WAITKIND_NO_RESUMED; - return null_ptid; - } - - event_child = get_thread_lwp (current_thread); - - /* linux_wait_for_event only returns an exit status for the last - child of a process. Report it. */ - if (WIFEXITED (w) || WIFSIGNALED (w)) - { - if (WIFEXITED (w)) - { - ourstatus->kind = TARGET_WAITKIND_EXITED; - ourstatus->value.integer = WEXITSTATUS (w); - - if (debug_threads) - { - debug_printf ("linux_wait_1 ret = %s, exited with " - "retcode %d\n", - target_pid_to_str (ptid_of (current_thread)), - WEXITSTATUS (w)); - debug_exit (); - } - } - else - { - ourstatus->kind = TARGET_WAITKIND_SIGNALLED; - ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (w)); - - if (debug_threads) - { - debug_printf ("linux_wait_1 ret = %s, terminated with " - "signal %d\n", - target_pid_to_str (ptid_of (current_thread)), - WTERMSIG (w)); - debug_exit (); - } - } - - if (ourstatus->kind == TARGET_WAITKIND_EXITED) - return filter_exit_event (event_child, ourstatus); - - return ptid_of (current_thread); - } - - /* If step-over executes a breakpoint instruction, in the case of a - hardware single step it means a gdb/gdbserver breakpoint had been - planted on top of a permanent breakpoint, in the case of a software - single step it may just mean that gdbserver hit the reinsert breakpoint. - The PC has been adjusted by save_stop_reason to point at - the breakpoint address. - So in the case of the hardware single step advance the PC manually - past the breakpoint and in the case of software single step advance only - if it's not the single_step_breakpoint we are hitting. - This avoids that a program would keep trapping a permanent breakpoint - forever. */ - if (step_over_bkpt != null_ptid - && event_child->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT - && (event_child->stepping - || !single_step_breakpoint_inserted_here (event_child->stop_pc))) - { - int increment_pc = 0; - int breakpoint_kind = 0; - CORE_ADDR stop_pc = event_child->stop_pc; - - breakpoint_kind = - the_target->breakpoint_kind_from_current_state (&stop_pc); - the_target->sw_breakpoint_from_kind (breakpoint_kind, &increment_pc); - - if (debug_threads) - { - debug_printf ("step-over for %s executed software breakpoint\n", - target_pid_to_str (ptid_of (current_thread))); - } - - if (increment_pc != 0) - { - struct regcache *regcache - = get_thread_regcache (current_thread, 1); - - event_child->stop_pc += increment_pc; - (*the_low_target.set_pc) (regcache, event_child->stop_pc); - - if (!(*the_low_target.breakpoint_at) (event_child->stop_pc)) - event_child->stop_reason = TARGET_STOPPED_BY_NO_REASON; - } - } - - /* If this event was not handled before, and is not a SIGTRAP, we - report it. SIGILL and SIGSEGV are also treated as traps in case - a breakpoint is inserted at the current PC. If this target does - not support internal breakpoints at all, we also report the - SIGTRAP without further processing; it's of no concern to us. */ - maybe_internal_trap - = (supports_breakpoints () - && (WSTOPSIG (w) == SIGTRAP - || ((WSTOPSIG (w) == SIGILL - || WSTOPSIG (w) == SIGSEGV) - && (*the_low_target.breakpoint_at) (event_child->stop_pc)))); - - if (maybe_internal_trap) - { - /* Handle anything that requires bookkeeping before deciding to - report the event or continue waiting. */ - - /* First check if we can explain the SIGTRAP with an internal - breakpoint, or if we should possibly report the event to GDB. - Do this before anything that may remove or insert a - breakpoint. */ - bp_explains_trap = breakpoint_inserted_here (event_child->stop_pc); - - /* We have a SIGTRAP, possibly a step-over dance has just - finished. If so, tweak the state machine accordingly, - reinsert breakpoints and delete any single-step - breakpoints. */ - step_over_finished = finish_step_over (event_child); - - /* Now invoke the callbacks of any internal breakpoints there. */ - check_breakpoints (event_child->stop_pc); - - /* Handle tracepoint data collecting. This may overflow the - trace buffer, and cause a tracing stop, removing - breakpoints. */ - trace_event = handle_tracepoints (event_child); - - if (bp_explains_trap) - { - if (debug_threads) - debug_printf ("Hit a gdbserver breakpoint.\n"); - } - } - else - { - /* We have some other signal, possibly a step-over dance was in - progress, and it should be cancelled too. */ - step_over_finished = finish_step_over (event_child); - } - - /* We have all the data we need. Either report the event to GDB, or - resume threads and keep waiting for more. */ - - /* If we're collecting a fast tracepoint, finish the collection and - move out of the jump pad before delivering a signal. See - linux_stabilize_threads. */ - - if (WIFSTOPPED (w) - && WSTOPSIG (w) != SIGTRAP - && supports_fast_tracepoints () - && agent_loaded_p ()) - { - if (debug_threads) - debug_printf ("Got signal %d for LWP %ld. Check if we need " - "to defer or adjust it.\n", - WSTOPSIG (w), lwpid_of (current_thread)); - - /* Allow debugging the jump pad itself. */ - if (current_thread->last_resume_kind != resume_step - && maybe_move_out_of_jump_pad (event_child, &w)) - { - enqueue_one_deferred_signal (event_child, &w); - - if (debug_threads) - debug_printf ("Signal %d for LWP %ld deferred (in jump pad)\n", - WSTOPSIG (w), lwpid_of (current_thread)); - - linux_resume_one_lwp (event_child, 0, 0, NULL); - - if (debug_threads) - debug_exit (); - return ignore_event (ourstatus); - } - } - - if (event_child->collecting_fast_tracepoint - != fast_tpoint_collect_result::not_collecting) - { - if (debug_threads) - debug_printf ("LWP %ld was trying to move out of the jump pad (%d). " - "Check if we're already there.\n", - lwpid_of (current_thread), - (int) event_child->collecting_fast_tracepoint); - - trace_event = 1; - - event_child->collecting_fast_tracepoint - = linux_fast_tracepoint_collecting (event_child, NULL); - - if (event_child->collecting_fast_tracepoint - != fast_tpoint_collect_result::before_insn) - { - /* No longer need this breakpoint. */ - if (event_child->exit_jump_pad_bkpt != NULL) - { - if (debug_threads) - debug_printf ("No longer need exit-jump-pad bkpt; removing it." - "stopping all threads momentarily.\n"); - - /* Other running threads could hit this breakpoint. - We don't handle moribund locations like GDB does, - instead we always pause all threads when removing - breakpoints, so that any step-over or - decr_pc_after_break adjustment is always taken - care of while the breakpoint is still - inserted. */ - stop_all_lwps (1, event_child); - - delete_breakpoint (event_child->exit_jump_pad_bkpt); - event_child->exit_jump_pad_bkpt = NULL; - - unstop_all_lwps (1, event_child); - - gdb_assert (event_child->suspended >= 0); - } - } - - if (event_child->collecting_fast_tracepoint - == fast_tpoint_collect_result::not_collecting) - { - if (debug_threads) - debug_printf ("fast tracepoint finished " - "collecting successfully.\n"); - - /* We may have a deferred signal to report. */ - if (dequeue_one_deferred_signal (event_child, &w)) - { - if (debug_threads) - debug_printf ("dequeued one signal.\n"); - } - else - { - if (debug_threads) - debug_printf ("no deferred signals.\n"); - - if (stabilizing_threads) - { - ourstatus->kind = TARGET_WAITKIND_STOPPED; - ourstatus->value.sig = GDB_SIGNAL_0; - - if (debug_threads) - { - debug_printf ("linux_wait_1 ret = %s, stopped " - "while stabilizing threads\n", - target_pid_to_str (ptid_of (current_thread))); - debug_exit (); - } - - return ptid_of (current_thread); - } - } - } - } - - /* Check whether GDB would be interested in this event. */ - - /* Check if GDB is interested in this syscall. */ - if (WIFSTOPPED (w) - && WSTOPSIG (w) == SYSCALL_SIGTRAP - && !gdb_catch_this_syscall_p (event_child)) - { - if (debug_threads) - { - debug_printf ("Ignored syscall for LWP %ld.\n", - lwpid_of (current_thread)); - } - - linux_resume_one_lwp (event_child, event_child->stepping, - 0, NULL); - - if (debug_threads) - debug_exit (); - return ignore_event (ourstatus); - } - - /* If GDB is not interested in this signal, don't stop other - threads, and don't report it to GDB. Just resume the inferior - right away. We do this for threading-related signals as well as - any that GDB specifically requested we ignore. But never ignore - SIGSTOP if we sent it ourselves, and do not ignore signals when - stepping - they may require special handling to skip the signal - handler. Also never ignore signals that could be caused by a - breakpoint. */ - if (WIFSTOPPED (w) - && current_thread->last_resume_kind != resume_step - && ( -#if defined (USE_THREAD_DB) && !defined (__ANDROID__) - (current_process ()->priv->thread_db != NULL - && (WSTOPSIG (w) == __SIGRTMIN - || WSTOPSIG (w) == __SIGRTMIN + 1)) - || -#endif - (cs.pass_signals[gdb_signal_from_host (WSTOPSIG (w))] - && !(WSTOPSIG (w) == SIGSTOP - && current_thread->last_resume_kind == resume_stop) - && !linux_wstatus_maybe_breakpoint (w)))) - { - siginfo_t info, *info_p; - - if (debug_threads) - debug_printf ("Ignored signal %d for LWP %ld.\n", - WSTOPSIG (w), lwpid_of (current_thread)); - - if (ptrace (PTRACE_GETSIGINFO, lwpid_of (current_thread), - (PTRACE_TYPE_ARG3) 0, &info) == 0) - info_p = &info; - else - info_p = NULL; - - if (step_over_finished) - { - /* We cancelled this thread's step-over above. We still - need to unsuspend all other LWPs, and set them back - running again while the signal handler runs. */ - unsuspend_all_lwps (event_child); - - /* Enqueue the pending signal info so that proceed_all_lwps - doesn't lose it. */ - enqueue_pending_signal (event_child, WSTOPSIG (w), info_p); - - proceed_all_lwps (); - } - else - { - linux_resume_one_lwp (event_child, event_child->stepping, - WSTOPSIG (w), info_p); - } - - if (debug_threads) - debug_exit (); - - return ignore_event (ourstatus); - } - - /* Note that all addresses are always "out of the step range" when - there's no range to begin with. */ - in_step_range = lwp_in_step_range (event_child); - - /* If GDB wanted this thread to single step, and the thread is out - of the step range, we always want to report the SIGTRAP, and let - GDB handle it. Watchpoints should always be reported. So should - signals we can't explain. A SIGTRAP we can't explain could be a - GDB breakpoint --- we may or not support Z0 breakpoints. If we - do, we're be able to handle GDB breakpoints on top of internal - breakpoints, by handling the internal breakpoint and still - reporting the event to GDB. If we don't, we're out of luck, GDB - won't see the breakpoint hit. If we see a single-step event but - the thread should be continuing, don't pass the trap to gdb. - That indicates that we had previously finished a single-step but - left the single-step pending -- see - complete_ongoing_step_over. */ - report_to_gdb = (!maybe_internal_trap - || (current_thread->last_resume_kind == resume_step - && !in_step_range) - || event_child->stop_reason == TARGET_STOPPED_BY_WATCHPOINT - || (!in_step_range - && !bp_explains_trap - && !trace_event - && !step_over_finished - && !(current_thread->last_resume_kind == resume_continue - && event_child->stop_reason == TARGET_STOPPED_BY_SINGLE_STEP)) - || (gdb_breakpoint_here (event_child->stop_pc) - && gdb_condition_true_at_breakpoint (event_child->stop_pc) - && gdb_no_commands_at_breakpoint (event_child->stop_pc)) - || event_child->waitstatus.kind != TARGET_WAITKIND_IGNORE); - - run_breakpoint_commands (event_child->stop_pc); - - /* We found no reason GDB would want us to stop. We either hit one - of our own breakpoints, or finished an internal step GDB - shouldn't know about. */ - if (!report_to_gdb) - { - if (debug_threads) - { - if (bp_explains_trap) - debug_printf ("Hit a gdbserver breakpoint.\n"); - if (step_over_finished) - debug_printf ("Step-over finished.\n"); - if (trace_event) - debug_printf ("Tracepoint event.\n"); - if (lwp_in_step_range (event_child)) - debug_printf ("Range stepping pc 0x%s [0x%s, 0x%s).\n", - paddress (event_child->stop_pc), - paddress (event_child->step_range_start), - paddress (event_child->step_range_end)); - } - - /* We're not reporting this breakpoint to GDB, so apply the - decr_pc_after_break adjustment to the inferior's regcache - ourselves. */ - - if (the_low_target.set_pc != NULL) - { - struct regcache *regcache - = get_thread_regcache (current_thread, 1); - (*the_low_target.set_pc) (regcache, event_child->stop_pc); - } - - if (step_over_finished) - { - /* If we have finished stepping over a breakpoint, we've - stopped and suspended all LWPs momentarily except the - stepping one. This is where we resume them all again. - We're going to keep waiting, so use proceed, which - handles stepping over the next breakpoint. */ - unsuspend_all_lwps (event_child); - } - else - { - /* Remove the single-step breakpoints if any. Note that - there isn't single-step breakpoint if we finished stepping - over. */ - if (can_software_single_step () - && has_single_step_breakpoints (current_thread)) - { - stop_all_lwps (0, event_child); - delete_single_step_breakpoints (current_thread); - unstop_all_lwps (0, event_child); - } - } - - if (debug_threads) - debug_printf ("proceeding all threads.\n"); - proceed_all_lwps (); - - if (debug_threads) - debug_exit (); - - return ignore_event (ourstatus); - } - - if (debug_threads) - { - if (event_child->waitstatus.kind != TARGET_WAITKIND_IGNORE) - { - std::string str - = target_waitstatus_to_string (&event_child->waitstatus); - - debug_printf ("LWP %ld: extended event with waitstatus %s\n", - lwpid_of (get_lwp_thread (event_child)), str.c_str ()); - } - if (current_thread->last_resume_kind == resume_step) - { - if (event_child->step_range_start == event_child->step_range_end) - debug_printf ("GDB wanted to single-step, reporting event.\n"); - else if (!lwp_in_step_range (event_child)) - debug_printf ("Out of step range, reporting event.\n"); - } - if (event_child->stop_reason == TARGET_STOPPED_BY_WATCHPOINT) - debug_printf ("Stopped by watchpoint.\n"); - else if (gdb_breakpoint_here (event_child->stop_pc)) - debug_printf ("Stopped by GDB breakpoint.\n"); - if (debug_threads) - debug_printf ("Hit a non-gdbserver trap event.\n"); - } - - /* Alright, we're going to report a stop. */ - - /* Remove single-step breakpoints. */ - if (can_software_single_step ()) - { - /* Remove single-step breakpoints or not. It it is true, stop all - lwps, so that other threads won't hit the breakpoint in the - staled memory. */ - int remove_single_step_breakpoints_p = 0; - - if (non_stop) - { - remove_single_step_breakpoints_p - = has_single_step_breakpoints (current_thread); - } - else - { - /* In all-stop, a stop reply cancels all previous resume - requests. Delete all single-step breakpoints. */ - - find_thread ([&] (thread_info *thread) { - if (has_single_step_breakpoints (thread)) - { - remove_single_step_breakpoints_p = 1; - return true; - } - - return false; - }); - } - - if (remove_single_step_breakpoints_p) - { - /* If we remove single-step breakpoints from memory, stop all lwps, - so that other threads won't hit the breakpoint in the staled - memory. */ - stop_all_lwps (0, event_child); - - if (non_stop) - { - gdb_assert (has_single_step_breakpoints (current_thread)); - delete_single_step_breakpoints (current_thread); - } - else - { - for_each_thread ([] (thread_info *thread){ - if (has_single_step_breakpoints (thread)) - delete_single_step_breakpoints (thread); - }); - } - - unstop_all_lwps (0, event_child); - } - } - - if (!stabilizing_threads) - { - /* In all-stop, stop all threads. */ - if (!non_stop) - stop_all_lwps (0, NULL); - - if (step_over_finished) - { - if (!non_stop) - { - /* If we were doing a step-over, all other threads but - the stepping one had been paused in start_step_over, - with their suspend counts incremented. We don't want - to do a full unstop/unpause, because we're in - all-stop mode (so we want threads stopped), but we - still need to unsuspend the other threads, to - decrement their `suspended' count back. */ - unsuspend_all_lwps (event_child); - } - else - { - /* If we just finished a step-over, then all threads had - been momentarily paused. In all-stop, that's fine, - we want threads stopped by now anyway. In non-stop, - we need to re-resume threads that GDB wanted to be - running. */ - unstop_all_lwps (1, event_child); - } - } - - /* If we're not waiting for a specific LWP, choose an event LWP - from among those that have had events. Giving equal priority - to all LWPs that have had events helps prevent - starvation. */ - if (ptid == minus_one_ptid) - { - event_child->status_pending_p = 1; - event_child->status_pending = w; - - select_event_lwp (&event_child); - - /* current_thread and event_child must stay in sync. */ - current_thread = get_lwp_thread (event_child); - - event_child->status_pending_p = 0; - w = event_child->status_pending; - } - - - /* Stabilize threads (move out of jump pads). */ - if (!non_stop) - stabilize_threads (); - } - else - { - /* If we just finished a step-over, then all threads had been - momentarily paused. In all-stop, that's fine, we want - threads stopped by now anyway. In non-stop, we need to - re-resume threads that GDB wanted to be running. */ - if (step_over_finished) - unstop_all_lwps (1, event_child); - } - - if (event_child->waitstatus.kind != TARGET_WAITKIND_IGNORE) - { - /* If the reported event is an exit, fork, vfork or exec, let - GDB know. */ - - /* Break the unreported fork relationship chain. */ - if (event_child->waitstatus.kind == TARGET_WAITKIND_FORKED - || event_child->waitstatus.kind == TARGET_WAITKIND_VFORKED) - { - event_child->fork_relative->fork_relative = NULL; - event_child->fork_relative = NULL; - } - - *ourstatus = event_child->waitstatus; - /* Clear the event lwp's waitstatus since we handled it already. */ - event_child->waitstatus.kind = TARGET_WAITKIND_IGNORE; - } - else - ourstatus->kind = TARGET_WAITKIND_STOPPED; - - /* Now that we've selected our final event LWP, un-adjust its PC if - it was a software breakpoint, and the client doesn't know we can - adjust the breakpoint ourselves. */ - if (event_child->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT - && !cs.swbreak_feature) - { - int decr_pc = the_low_target.decr_pc_after_break; - - if (decr_pc != 0) - { - struct regcache *regcache - = get_thread_regcache (current_thread, 1); - (*the_low_target.set_pc) (regcache, event_child->stop_pc + decr_pc); - } - } - - if (WSTOPSIG (w) == SYSCALL_SIGTRAP) - { - get_syscall_trapinfo (event_child, - &ourstatus->value.syscall_number); - ourstatus->kind = event_child->syscall_state; - } - else if (current_thread->last_resume_kind == resume_stop - && WSTOPSIG (w) == SIGSTOP) - { - /* A thread that has been requested to stop by GDB with vCont;t, - and it stopped cleanly, so report as SIG0. The use of - SIGSTOP is an implementation detail. */ - ourstatus->value.sig = GDB_SIGNAL_0; - } - else if (current_thread->last_resume_kind == resume_stop - && WSTOPSIG (w) != SIGSTOP) - { - /* A thread that has been requested to stop by GDB with vCont;t, - but, it stopped for other reasons. */ - ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (w)); - } - else if (ourstatus->kind == TARGET_WAITKIND_STOPPED) - { - ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (w)); - } - - gdb_assert (step_over_bkpt == null_ptid); - - if (debug_threads) - { - debug_printf ("linux_wait_1 ret = %s, %d, %d\n", - target_pid_to_str (ptid_of (current_thread)), - ourstatus->kind, ourstatus->value.sig); - debug_exit (); - } - - if (ourstatus->kind == TARGET_WAITKIND_EXITED) - return filter_exit_event (event_child, ourstatus); - - return ptid_of (current_thread); -} - -/* Get rid of any pending event in the pipe. */ -static void -async_file_flush (void) -{ - int ret; - char buf; - - do - ret = read (linux_event_pipe[0], &buf, 1); - while (ret >= 0 || (ret == -1 && errno == EINTR)); -} - -/* Put something in the pipe, so the event loop wakes up. */ -static void -async_file_mark (void) -{ - int ret; - - async_file_flush (); - - do - ret = write (linux_event_pipe[1], "+", 1); - while (ret == 0 || (ret == -1 && errno == EINTR)); - - /* Ignore EAGAIN. If the pipe is full, the event loop will already - be awakened anyway. */ -} - -static ptid_t -linux_wait (ptid_t ptid, - struct target_waitstatus *ourstatus, int target_options) -{ - ptid_t event_ptid; - - /* Flush the async file first. */ - if (target_is_async_p ()) - async_file_flush (); - - do - { - event_ptid = linux_wait_1 (ptid, ourstatus, target_options); - } - while ((target_options & TARGET_WNOHANG) == 0 - && event_ptid == null_ptid - && ourstatus->kind == TARGET_WAITKIND_IGNORE); - - /* If at least one stop was reported, there may be more. A single - SIGCHLD can signal more than one child stop. */ - if (target_is_async_p () - && (target_options & TARGET_WNOHANG) != 0 - && event_ptid != null_ptid) - async_file_mark (); - - return event_ptid; -} - -/* Send a signal to an LWP. */ - -static int -kill_lwp (unsigned long lwpid, int signo) -{ - int ret; - - errno = 0; - ret = syscall (__NR_tkill, lwpid, signo); - if (errno == ENOSYS) - { - /* If tkill fails, then we are not using nptl threads, a - configuration we no longer support. */ - perror_with_name (("tkill")); - } - return ret; -} - -void -linux_stop_lwp (struct lwp_info *lwp) -{ - send_sigstop (lwp); -} - -static void -send_sigstop (struct lwp_info *lwp) -{ - int pid; - - pid = lwpid_of (get_lwp_thread (lwp)); - - /* If we already have a pending stop signal for this process, don't - send another. */ - if (lwp->stop_expected) - { - if (debug_threads) - debug_printf ("Have pending sigstop for lwp %d\n", pid); - - return; - } - - if (debug_threads) - debug_printf ("Sending sigstop to lwp %d\n", pid); - - lwp->stop_expected = 1; - kill_lwp (pid, SIGSTOP); -} - -static void -send_sigstop (thread_info *thread, lwp_info *except) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - /* Ignore EXCEPT. */ - if (lwp == except) - return; - - if (lwp->stopped) - return; - - send_sigstop (lwp); -} - -/* Increment the suspend count of an LWP, and stop it, if not stopped - yet. */ -static void -suspend_and_send_sigstop (thread_info *thread, lwp_info *except) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - /* Ignore EXCEPT. */ - if (lwp == except) - return; - - lwp_suspended_inc (lwp); - - send_sigstop (thread, except); -} - -static void -mark_lwp_dead (struct lwp_info *lwp, int wstat) -{ - /* Store the exit status for later. */ - lwp->status_pending_p = 1; - lwp->status_pending = wstat; - - /* Store in waitstatus as well, as there's nothing else to process - for this event. */ - if (WIFEXITED (wstat)) - { - lwp->waitstatus.kind = TARGET_WAITKIND_EXITED; - lwp->waitstatus.value.integer = WEXITSTATUS (wstat); - } - else if (WIFSIGNALED (wstat)) - { - lwp->waitstatus.kind = TARGET_WAITKIND_SIGNALLED; - lwp->waitstatus.value.sig = gdb_signal_from_host (WTERMSIG (wstat)); - } - - /* Prevent trying to stop it. */ - lwp->stopped = 1; - - /* No further stops are expected from a dead lwp. */ - lwp->stop_expected = 0; -} - -/* Return true if LWP has exited already, and has a pending exit event - to report to GDB. */ - -static int -lwp_is_marked_dead (struct lwp_info *lwp) -{ - return (lwp->status_pending_p - && (WIFEXITED (lwp->status_pending) - || WIFSIGNALED (lwp->status_pending))); -} - -/* Wait for all children to stop for the SIGSTOPs we just queued. */ - -static void -wait_for_sigstop (void) -{ - struct thread_info *saved_thread; - ptid_t saved_tid; - int wstat; - int ret; - - saved_thread = current_thread; - if (saved_thread != NULL) - saved_tid = saved_thread->id; - else - saved_tid = null_ptid; /* avoid bogus unused warning */ - - if (debug_threads) - debug_printf ("wait_for_sigstop: pulling events\n"); - - /* Passing NULL_PTID as filter indicates we want all events to be - left pending. Eventually this returns when there are no - unwaited-for children left. */ - ret = linux_wait_for_event_filtered (minus_one_ptid, null_ptid, - &wstat, __WALL); - gdb_assert (ret == -1); - - if (saved_thread == NULL || linux_thread_alive (saved_tid)) - current_thread = saved_thread; - else - { - if (debug_threads) - debug_printf ("Previously current thread died.\n"); - - /* We can't change the current inferior behind GDB's back, - otherwise, a subsequent command may apply to the wrong - process. */ - current_thread = NULL; - } -} - -/* Returns true if THREAD is stopped in a jump pad, and we can't - move it out, because we need to report the stop event to GDB. For - example, if the user puts a breakpoint in the jump pad, it's - because she wants to debug it. */ - -static bool -stuck_in_jump_pad_callback (thread_info *thread) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - if (lwp->suspended != 0) - { - internal_error (__FILE__, __LINE__, - "LWP %ld is suspended, suspended=%d\n", - lwpid_of (thread), lwp->suspended); - } - gdb_assert (lwp->stopped); - - /* Allow debugging the jump pad, gdb_collect, etc.. */ - return (supports_fast_tracepoints () - && agent_loaded_p () - && (gdb_breakpoint_here (lwp->stop_pc) - || lwp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT - || thread->last_resume_kind == resume_step) - && (linux_fast_tracepoint_collecting (lwp, NULL) - != fast_tpoint_collect_result::not_collecting)); -} - -static void -move_out_of_jump_pad_callback (thread_info *thread) -{ - struct thread_info *saved_thread; - struct lwp_info *lwp = get_thread_lwp (thread); - int *wstat; - - if (lwp->suspended != 0) - { - internal_error (__FILE__, __LINE__, - "LWP %ld is suspended, suspended=%d\n", - lwpid_of (thread), lwp->suspended); - } - gdb_assert (lwp->stopped); - - /* For gdb_breakpoint_here. */ - saved_thread = current_thread; - current_thread = thread; - - wstat = lwp->status_pending_p ? &lwp->status_pending : NULL; - - /* Allow debugging the jump pad, gdb_collect, etc. */ - if (!gdb_breakpoint_here (lwp->stop_pc) - && lwp->stop_reason != TARGET_STOPPED_BY_WATCHPOINT - && thread->last_resume_kind != resume_step - && maybe_move_out_of_jump_pad (lwp, wstat)) - { - if (debug_threads) - debug_printf ("LWP %ld needs stabilizing (in jump pad)\n", - lwpid_of (thread)); - - if (wstat) - { - lwp->status_pending_p = 0; - enqueue_one_deferred_signal (lwp, wstat); - - if (debug_threads) - debug_printf ("Signal %d for LWP %ld deferred " - "(in jump pad)\n", - WSTOPSIG (*wstat), lwpid_of (thread)); - } - - linux_resume_one_lwp (lwp, 0, 0, NULL); - } - else - lwp_suspended_inc (lwp); - - current_thread = saved_thread; -} - -static bool -lwp_running (thread_info *thread) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - if (lwp_is_marked_dead (lwp)) - return false; - - return !lwp->stopped; -} - -/* Stop all lwps that aren't stopped yet, except EXCEPT, if not NULL. - If SUSPEND, then also increase the suspend count of every LWP, - except EXCEPT. */ - -static void -stop_all_lwps (int suspend, struct lwp_info *except) -{ - /* Should not be called recursively. */ - gdb_assert (stopping_threads == NOT_STOPPING_THREADS); - - if (debug_threads) - { - debug_enter (); - debug_printf ("stop_all_lwps (%s, except=%s)\n", - suspend ? "stop-and-suspend" : "stop", - except != NULL - ? target_pid_to_str (ptid_of (get_lwp_thread (except))) - : "none"); - } - - stopping_threads = (suspend - ? STOPPING_AND_SUSPENDING_THREADS - : STOPPING_THREADS); - - if (suspend) - for_each_thread ([&] (thread_info *thread) - { - suspend_and_send_sigstop (thread, except); - }); - else - for_each_thread ([&] (thread_info *thread) - { - send_sigstop (thread, except); - }); - - wait_for_sigstop (); - stopping_threads = NOT_STOPPING_THREADS; - - if (debug_threads) - { - debug_printf ("stop_all_lwps done, setting stopping_threads " - "back to !stopping\n"); - debug_exit (); - } -} - -/* Enqueue one signal in the chain of signals which need to be - delivered to this process on next resume. */ - -static void -enqueue_pending_signal (struct lwp_info *lwp, int signal, siginfo_t *info) -{ - struct pending_signals *p_sig = XNEW (struct pending_signals); - - p_sig->prev = lwp->pending_signals; - p_sig->signal = signal; - if (info == NULL) - memset (&p_sig->info, 0, sizeof (siginfo_t)); - else - memcpy (&p_sig->info, info, sizeof (siginfo_t)); - lwp->pending_signals = p_sig; -} - -/* Install breakpoints for software single stepping. */ - -static void -install_software_single_step_breakpoints (struct lwp_info *lwp) -{ - struct thread_info *thread = get_lwp_thread (lwp); - struct regcache *regcache = get_thread_regcache (thread, 1); - - scoped_restore save_current_thread = make_scoped_restore (¤t_thread); - - current_thread = thread; - std::vector<CORE_ADDR> next_pcs = the_low_target.get_next_pcs (regcache); - - for (CORE_ADDR pc : next_pcs) - set_single_step_breakpoint (pc, current_ptid); -} - -/* Single step via hardware or software single step. - Return 1 if hardware single stepping, 0 if software single stepping - or can't single step. */ - -static int -single_step (struct lwp_info* lwp) -{ - int step = 0; - - if (can_hardware_single_step ()) - { - step = 1; - } - else if (can_software_single_step ()) - { - install_software_single_step_breakpoints (lwp); - step = 0; - } - else - { - if (debug_threads) - debug_printf ("stepping is not implemented on this target"); - } - - return step; -} - -/* The signal can be delivered to the inferior if we are not trying to - finish a fast tracepoint collect. Since signal can be delivered in - the step-over, the program may go to signal handler and trap again - after return from the signal handler. We can live with the spurious - double traps. */ - -static int -lwp_signal_can_be_delivered (struct lwp_info *lwp) -{ - return (lwp->collecting_fast_tracepoint - == fast_tpoint_collect_result::not_collecting); -} - -/* Resume execution of LWP. If STEP is nonzero, single-step it. If - SIGNAL is nonzero, give it that signal. */ - -static void -linux_resume_one_lwp_throw (struct lwp_info *lwp, - int step, int signal, siginfo_t *info) -{ - struct thread_info *thread = get_lwp_thread (lwp); - struct thread_info *saved_thread; - int ptrace_request; - struct process_info *proc = get_thread_process (thread); - - /* Note that target description may not be initialised - (proc->tdesc == NULL) at this point because the program hasn't - stopped at the first instruction yet. It means GDBserver skips - the extra traps from the wrapper program (see option --wrapper). - Code in this function that requires register access should be - guarded by proc->tdesc == NULL or something else. */ - - if (lwp->stopped == 0) - return; - - gdb_assert (lwp->waitstatus.kind == TARGET_WAITKIND_IGNORE); - - fast_tpoint_collect_result fast_tp_collecting - = lwp->collecting_fast_tracepoint; - - gdb_assert (!stabilizing_threads - || (fast_tp_collecting - != fast_tpoint_collect_result::not_collecting)); - - /* Cancel actions that rely on GDB not changing the PC (e.g., the - user used the "jump" command, or "set $pc = foo"). */ - if (thread->while_stepping != NULL && lwp->stop_pc != get_pc (lwp)) - { - /* Collecting 'while-stepping' actions doesn't make sense - anymore. */ - release_while_stepping_state_list (thread); - } - - /* If we have pending signals or status, and a new signal, enqueue the - signal. Also enqueue the signal if it can't be delivered to the - inferior right now. */ - if (signal != 0 - && (lwp->status_pending_p - || lwp->pending_signals != NULL - || !lwp_signal_can_be_delivered (lwp))) - { - enqueue_pending_signal (lwp, signal, info); - - /* Postpone any pending signal. It was enqueued above. */ - signal = 0; - } - - if (lwp->status_pending_p) - { - if (debug_threads) - debug_printf ("Not resuming lwp %ld (%s, stop %s);" - " has pending status\n", - lwpid_of (thread), step ? "step" : "continue", - lwp->stop_expected ? "expected" : "not expected"); - return; - } - - saved_thread = current_thread; - current_thread = thread; - - /* This bit needs some thinking about. If we get a signal that - we must report while a single-step reinsert is still pending, - we often end up resuming the thread. It might be better to - (ew) allow a stack of pending events; then we could be sure that - the reinsert happened right away and not lose any signals. - - Making this stack would also shrink the window in which breakpoints are - uninserted (see comment in linux_wait_for_lwp) but not enough for - complete correctness, so it won't solve that problem. It may be - worthwhile just to solve this one, however. */ - if (lwp->bp_reinsert != 0) - { - if (debug_threads) - debug_printf (" pending reinsert at 0x%s\n", - paddress (lwp->bp_reinsert)); - - if (can_hardware_single_step ()) - { - if (fast_tp_collecting == fast_tpoint_collect_result::not_collecting) - { - if (step == 0) - warning ("BAD - reinserting but not stepping."); - if (lwp->suspended) - warning ("BAD - reinserting and suspended(%d).", - lwp->suspended); - } - } - - step = maybe_hw_step (thread); - } - - if (fast_tp_collecting == fast_tpoint_collect_result::before_insn) - { - if (debug_threads) - debug_printf ("lwp %ld wants to get out of fast tracepoint jump pad" - " (exit-jump-pad-bkpt)\n", - lwpid_of (thread)); - } - else if (fast_tp_collecting == fast_tpoint_collect_result::at_insn) - { - if (debug_threads) - debug_printf ("lwp %ld wants to get out of fast tracepoint jump pad" - " single-stepping\n", - lwpid_of (thread)); - - if (can_hardware_single_step ()) - step = 1; - else - { - internal_error (__FILE__, __LINE__, - "moving out of jump pad single-stepping" - " not implemented on this target"); - } - } - - /* If we have while-stepping actions in this thread set it stepping. - If we have a signal to deliver, it may or may not be set to - SIG_IGN, we don't know. Assume so, and allow collecting - while-stepping into a signal handler. A possible smart thing to - do would be to set an internal breakpoint at the signal return - address, continue, and carry on catching this while-stepping - action only when that breakpoint is hit. A future - enhancement. */ - if (thread->while_stepping != NULL) - { - if (debug_threads) - debug_printf ("lwp %ld has a while-stepping action -> forcing step.\n", - lwpid_of (thread)); - - step = single_step (lwp); - } - - if (proc->tdesc != NULL && the_low_target.get_pc != NULL) - { - struct regcache *regcache = get_thread_regcache (current_thread, 1); - - lwp->stop_pc = (*the_low_target.get_pc) (regcache); - - if (debug_threads) - { - debug_printf (" %s from pc 0x%lx\n", step ? "step" : "continue", - (long) lwp->stop_pc); - } - } - - /* If we have pending signals, consume one if it can be delivered to - the inferior. */ - if (lwp->pending_signals != NULL && lwp_signal_can_be_delivered (lwp)) - { - struct pending_signals **p_sig; - - p_sig = &lwp->pending_signals; - while ((*p_sig)->prev != NULL) - p_sig = &(*p_sig)->prev; - - signal = (*p_sig)->signal; - if ((*p_sig)->info.si_signo != 0) - ptrace (PTRACE_SETSIGINFO, lwpid_of (thread), (PTRACE_TYPE_ARG3) 0, - &(*p_sig)->info); - - free (*p_sig); - *p_sig = NULL; - } - - if (debug_threads) - debug_printf ("Resuming lwp %ld (%s, signal %d, stop %s)\n", - lwpid_of (thread), step ? "step" : "continue", signal, - lwp->stop_expected ? "expected" : "not expected"); - - if (the_low_target.prepare_to_resume != NULL) - the_low_target.prepare_to_resume (lwp); - - regcache_invalidate_thread (thread); - errno = 0; - lwp->stepping = step; - if (step) - ptrace_request = PTRACE_SINGLESTEP; - else if (gdb_catching_syscalls_p (lwp)) - ptrace_request = PTRACE_SYSCALL; - else - ptrace_request = PTRACE_CONT; - ptrace (ptrace_request, - lwpid_of (thread), - (PTRACE_TYPE_ARG3) 0, - /* Coerce to a uintptr_t first to avoid potential gcc warning - of coercing an 8 byte integer to a 4 byte pointer. */ - (PTRACE_TYPE_ARG4) (uintptr_t) signal); - - current_thread = saved_thread; - if (errno) - perror_with_name ("resuming thread"); - - /* Successfully resumed. Clear state that no longer makes sense, - and mark the LWP as running. Must not do this before resuming - otherwise if that fails other code will be confused. E.g., we'd - later try to stop the LWP and hang forever waiting for a stop - status. Note that we must not throw after this is cleared, - otherwise handle_zombie_lwp_error would get confused. */ - lwp->stopped = 0; - lwp->stop_reason = TARGET_STOPPED_BY_NO_REASON; -} - -/* Called when we try to resume a stopped LWP and that errors out. If - the LWP is no longer in ptrace-stopped state (meaning it's zombie, - or about to become), discard the error, clear any pending status - the LWP may have, and return true (we'll collect the exit status - soon enough). Otherwise, return false. */ - -static int -check_ptrace_stopped_lwp_gone (struct lwp_info *lp) -{ - struct thread_info *thread = get_lwp_thread (lp); - - /* If we get an error after resuming the LWP successfully, we'd - confuse !T state for the LWP being gone. */ - gdb_assert (lp->stopped); - - /* We can't just check whether the LWP is in 'Z (Zombie)' state, - because even if ptrace failed with ESRCH, the tracee may be "not - yet fully dead", but already refusing ptrace requests. In that - case the tracee has 'R (Running)' state for a little bit - (observed in Linux 3.18). See also the note on ESRCH in the - ptrace(2) man page. Instead, check whether the LWP has any state - other than ptrace-stopped. */ - - /* Don't assume anything if /proc/PID/status can't be read. */ - if (linux_proc_pid_is_trace_stopped_nowarn (lwpid_of (thread)) == 0) - { - lp->stop_reason = TARGET_STOPPED_BY_NO_REASON; - lp->status_pending_p = 0; - return 1; - } - return 0; -} - -/* Like linux_resume_one_lwp_throw, but no error is thrown if the LWP - disappears while we try to resume it. */ - -static void -linux_resume_one_lwp (struct lwp_info *lwp, - int step, int signal, siginfo_t *info) -{ - try - { - linux_resume_one_lwp_throw (lwp, step, signal, info); - } - catch (const gdb_exception_error &ex) - { - if (!check_ptrace_stopped_lwp_gone (lwp)) - throw; - } -} - -/* This function is called once per thread via for_each_thread. - We look up which resume request applies to THREAD and mark it with a - pointer to the appropriate resume request. - - This algorithm is O(threads * resume elements), but resume elements - is small (and will remain small at least until GDB supports thread - suspension). */ - -static void -linux_set_resume_request (thread_info *thread, thread_resume *resume, size_t n) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - for (int ndx = 0; ndx < n; ndx++) - { - ptid_t ptid = resume[ndx].thread; - if (ptid == minus_one_ptid - || ptid == thread->id - /* Handle both 'pPID' and 'pPID.-1' as meaning 'all threads - of PID'. */ - || (ptid.pid () == pid_of (thread) - && (ptid.is_pid () - || ptid.lwp () == -1))) - { - if (resume[ndx].kind == resume_stop - && thread->last_resume_kind == resume_stop) - { - if (debug_threads) - debug_printf ("already %s LWP %ld at GDB's request\n", - (thread->last_status.kind - == TARGET_WAITKIND_STOPPED) - ? "stopped" - : "stopping", - lwpid_of (thread)); - - continue; - } - - /* Ignore (wildcard) resume requests for already-resumed - threads. */ - if (resume[ndx].kind != resume_stop - && thread->last_resume_kind != resume_stop) - { - if (debug_threads) - debug_printf ("already %s LWP %ld at GDB's request\n", - (thread->last_resume_kind - == resume_step) - ? "stepping" - : "continuing", - lwpid_of (thread)); - continue; - } - - /* Don't let wildcard resumes resume fork children that GDB - does not yet know are new fork children. */ - if (lwp->fork_relative != NULL) - { - struct lwp_info *rel = lwp->fork_relative; - - if (rel->status_pending_p - && (rel->waitstatus.kind == TARGET_WAITKIND_FORKED - || rel->waitstatus.kind == TARGET_WAITKIND_VFORKED)) - { - if (debug_threads) - debug_printf ("not resuming LWP %ld: has queued stop reply\n", - lwpid_of (thread)); - continue; - } - } - - /* If the thread has a pending event that has already been - reported to GDBserver core, but GDB has not pulled the - event out of the vStopped queue yet, likewise, ignore the - (wildcard) resume request. */ - if (in_queued_stop_replies (thread->id)) - { - if (debug_threads) - debug_printf ("not resuming LWP %ld: has queued stop reply\n", - lwpid_of (thread)); - continue; - } - - lwp->resume = &resume[ndx]; - thread->last_resume_kind = lwp->resume->kind; - - lwp->step_range_start = lwp->resume->step_range_start; - lwp->step_range_end = lwp->resume->step_range_end; - - /* If we had a deferred signal to report, dequeue one now. - This can happen if LWP gets more than one signal while - trying to get out of a jump pad. */ - if (lwp->stopped - && !lwp->status_pending_p - && dequeue_one_deferred_signal (lwp, &lwp->status_pending)) - { - lwp->status_pending_p = 1; - - if (debug_threads) - debug_printf ("Dequeueing deferred signal %d for LWP %ld, " - "leaving status pending.\n", - WSTOPSIG (lwp->status_pending), - lwpid_of (thread)); - } - - return; - } - } - - /* No resume action for this thread. */ - lwp->resume = NULL; -} - -/* find_thread callback for linux_resume. Return true if this lwp has an - interesting status pending. */ - -static bool -resume_status_pending_p (thread_info *thread) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - /* LWPs which will not be resumed are not interesting, because - we might not wait for them next time through linux_wait. */ - if (lwp->resume == NULL) - return false; - - return thread_still_has_status_pending_p (thread); -} - -/* Return 1 if this lwp that GDB wants running is stopped at an - internal breakpoint that we need to step over. It assumes that any - required STOP_PC adjustment has already been propagated to the - inferior's regcache. */ - -static bool -need_step_over_p (thread_info *thread) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - struct thread_info *saved_thread; - CORE_ADDR pc; - struct process_info *proc = get_thread_process (thread); - - /* GDBserver is skipping the extra traps from the wrapper program, - don't have to do step over. */ - if (proc->tdesc == NULL) - return false; - - /* LWPs which will not be resumed are not interesting, because we - might not wait for them next time through linux_wait. */ - - if (!lwp->stopped) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? Ignoring, not stopped\n", - lwpid_of (thread)); - return false; - } - - if (thread->last_resume_kind == resume_stop) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? Ignoring, should remain" - " stopped\n", - lwpid_of (thread)); - return false; - } - - gdb_assert (lwp->suspended >= 0); - - if (lwp->suspended) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? Ignoring, suspended\n", - lwpid_of (thread)); - return false; - } - - if (lwp->status_pending_p) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? Ignoring, has pending" - " status.\n", - lwpid_of (thread)); - return false; - } - - /* Note: PC, not STOP_PC. Either GDB has adjusted the PC already, - or we have. */ - pc = get_pc (lwp); - - /* If the PC has changed since we stopped, then don't do anything, - and let the breakpoint/tracepoint be hit. This happens if, for - instance, GDB handled the decr_pc_after_break subtraction itself, - GDB is OOL stepping this thread, or the user has issued a "jump" - command, or poked thread's registers herself. */ - if (pc != lwp->stop_pc) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? Cancelling, PC was changed. " - "Old stop_pc was 0x%s, PC is now 0x%s\n", - lwpid_of (thread), - paddress (lwp->stop_pc), paddress (pc)); - return false; - } - - /* On software single step target, resume the inferior with signal - rather than stepping over. */ - if (can_software_single_step () - && lwp->pending_signals != NULL - && lwp_signal_can_be_delivered (lwp)) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? Ignoring, has pending" - " signals.\n", - lwpid_of (thread)); - - return false; - } - - saved_thread = current_thread; - current_thread = thread; - - /* We can only step over breakpoints we know about. */ - if (breakpoint_here (pc) || fast_tracepoint_jump_here (pc)) - { - /* Don't step over a breakpoint that GDB expects to hit - though. If the condition is being evaluated on the target's side - and it evaluate to false, step over this breakpoint as well. */ - if (gdb_breakpoint_here (pc) - && gdb_condition_true_at_breakpoint (pc) - && gdb_no_commands_at_breakpoint (pc)) - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? yes, but found" - " GDB breakpoint at 0x%s; skipping step over\n", - lwpid_of (thread), paddress (pc)); - - current_thread = saved_thread; - return false; - } - else - { - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? yes, " - "found breakpoint at 0x%s\n", - lwpid_of (thread), paddress (pc)); - - /* We've found an lwp that needs stepping over --- return 1 so - that find_thread stops looking. */ - current_thread = saved_thread; - - return true; - } - } - - current_thread = saved_thread; - - if (debug_threads) - debug_printf ("Need step over [LWP %ld]? No, no breakpoint found" - " at 0x%s\n", - lwpid_of (thread), paddress (pc)); - - return false; -} - -/* Start a step-over operation on LWP. When LWP stopped at a - breakpoint, to make progress, we need to remove the breakpoint out - of the way. If we let other threads run while we do that, they may - pass by the breakpoint location and miss hitting it. To avoid - that, a step-over momentarily stops all threads while LWP is - single-stepped by either hardware or software while the breakpoint - is temporarily uninserted from the inferior. When the single-step - finishes, we reinsert the breakpoint, and let all threads that are - supposed to be running, run again. */ - -static int -start_step_over (struct lwp_info *lwp) -{ - struct thread_info *thread = get_lwp_thread (lwp); - struct thread_info *saved_thread; - CORE_ADDR pc; - int step; - - if (debug_threads) - debug_printf ("Starting step-over on LWP %ld. Stopping all threads\n", - lwpid_of (thread)); - - stop_all_lwps (1, lwp); - - if (lwp->suspended != 0) - { - internal_error (__FILE__, __LINE__, - "LWP %ld suspended=%d\n", lwpid_of (thread), - lwp->suspended); - } - - if (debug_threads) - debug_printf ("Done stopping all threads for step-over.\n"); - - /* Note, we should always reach here with an already adjusted PC, - either by GDB (if we're resuming due to GDB's request), or by our - caller, if we just finished handling an internal breakpoint GDB - shouldn't care about. */ - pc = get_pc (lwp); - - saved_thread = current_thread; - current_thread = thread; - - lwp->bp_reinsert = pc; - uninsert_breakpoints_at (pc); - uninsert_fast_tracepoint_jumps_at (pc); - - step = single_step (lwp); - - current_thread = saved_thread; - - linux_resume_one_lwp (lwp, step, 0, NULL); - - /* Require next event from this LWP. */ - step_over_bkpt = thread->id; - return 1; -} - -/* Finish a step-over. Reinsert the breakpoint we had uninserted in - start_step_over, if still there, and delete any single-step - breakpoints we've set, on non hardware single-step targets. */ - -static int -finish_step_over (struct lwp_info *lwp) -{ - if (lwp->bp_reinsert != 0) - { - struct thread_info *saved_thread = current_thread; - - if (debug_threads) - debug_printf ("Finished step over.\n"); - - current_thread = get_lwp_thread (lwp); - - /* Reinsert any breakpoint at LWP->BP_REINSERT. Note that there - may be no breakpoint to reinsert there by now. */ - reinsert_breakpoints_at (lwp->bp_reinsert); - reinsert_fast_tracepoint_jumps_at (lwp->bp_reinsert); - - lwp->bp_reinsert = 0; - - /* Delete any single-step breakpoints. No longer needed. We - don't have to worry about other threads hitting this trap, - and later not being able to explain it, because we were - stepping over a breakpoint, and we hold all threads but - LWP stopped while doing that. */ - if (!can_hardware_single_step ()) - { - gdb_assert (has_single_step_breakpoints (current_thread)); - delete_single_step_breakpoints (current_thread); - } - - step_over_bkpt = null_ptid; - current_thread = saved_thread; - return 1; - } - else - return 0; -} - -/* If there's a step over in progress, wait until all threads stop - (that is, until the stepping thread finishes its step), and - unsuspend all lwps. The stepping thread ends with its status - pending, which is processed later when we get back to processing - events. */ - -static void -complete_ongoing_step_over (void) -{ - if (step_over_bkpt != null_ptid) - { - struct lwp_info *lwp; - int wstat; - int ret; - - if (debug_threads) - debug_printf ("detach: step over in progress, finish it first\n"); - - /* Passing NULL_PTID as filter indicates we want all events to - be left pending. Eventually this returns when there are no - unwaited-for children left. */ - ret = linux_wait_for_event_filtered (minus_one_ptid, null_ptid, - &wstat, __WALL); - gdb_assert (ret == -1); - - lwp = find_lwp_pid (step_over_bkpt); - if (lwp != NULL) - finish_step_over (lwp); - step_over_bkpt = null_ptid; - unsuspend_all_lwps (lwp); - } -} - -/* This function is called once per thread. We check the thread's resume - request, which will tell us whether to resume, step, or leave the thread - stopped; and what signal, if any, it should be sent. - - For threads which we aren't explicitly told otherwise, we preserve - the stepping flag; this is used for stepping over gdbserver-placed - breakpoints. - - If pending_flags was set in any thread, we queue any needed - signals, since we won't actually resume. We already have a pending - event to report, so we don't need to preserve any step requests; - they should be re-issued if necessary. */ - -static void -linux_resume_one_thread (thread_info *thread, bool leave_all_stopped) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - int leave_pending; - - if (lwp->resume == NULL) - return; - - if (lwp->resume->kind == resume_stop) - { - if (debug_threads) - debug_printf ("resume_stop request for LWP %ld\n", lwpid_of (thread)); - - if (!lwp->stopped) - { - if (debug_threads) - debug_printf ("stopping LWP %ld\n", lwpid_of (thread)); - - /* Stop the thread, and wait for the event asynchronously, - through the event loop. */ - send_sigstop (lwp); - } - else - { - if (debug_threads) - debug_printf ("already stopped LWP %ld\n", - lwpid_of (thread)); - - /* The LWP may have been stopped in an internal event that - was not meant to be notified back to GDB (e.g., gdbserver - breakpoint), so we should be reporting a stop event in - this case too. */ - - /* If the thread already has a pending SIGSTOP, this is a - no-op. Otherwise, something later will presumably resume - the thread and this will cause it to cancel any pending - operation, due to last_resume_kind == resume_stop. If - the thread already has a pending status to report, we - will still report it the next time we wait - see - status_pending_p_callback. */ - - /* If we already have a pending signal to report, then - there's no need to queue a SIGSTOP, as this means we're - midway through moving the LWP out of the jumppad, and we - will report the pending signal as soon as that is - finished. */ - if (lwp->pending_signals_to_report == NULL) - send_sigstop (lwp); - } - - /* For stop requests, we're done. */ - lwp->resume = NULL; - thread->last_status.kind = TARGET_WAITKIND_IGNORE; - return; - } - - /* If this thread which is about to be resumed has a pending status, - then don't resume it - we can just report the pending status. - Likewise if it is suspended, because e.g., another thread is - stepping past a breakpoint. Make sure to queue any signals that - would otherwise be sent. In all-stop mode, we do this decision - based on if *any* thread has a pending status. If there's a - thread that needs the step-over-breakpoint dance, then don't - resume any other thread but that particular one. */ - leave_pending = (lwp->suspended - || lwp->status_pending_p - || leave_all_stopped); - - /* If we have a new signal, enqueue the signal. */ - if (lwp->resume->sig != 0) - { - siginfo_t info, *info_p; - - /* If this is the same signal we were previously stopped by, - make sure to queue its siginfo. */ - if (WIFSTOPPED (lwp->last_status) - && WSTOPSIG (lwp->last_status) == lwp->resume->sig - && ptrace (PTRACE_GETSIGINFO, lwpid_of (thread), - (PTRACE_TYPE_ARG3) 0, &info) == 0) - info_p = &info; - else - info_p = NULL; - - enqueue_pending_signal (lwp, lwp->resume->sig, info_p); - } - - if (!leave_pending) - { - if (debug_threads) - debug_printf ("resuming LWP %ld\n", lwpid_of (thread)); - - proceed_one_lwp (thread, NULL); - } - else - { - if (debug_threads) - debug_printf ("leaving LWP %ld stopped\n", lwpid_of (thread)); - } - - thread->last_status.kind = TARGET_WAITKIND_IGNORE; - lwp->resume = NULL; -} - -static void -linux_resume (struct thread_resume *resume_info, size_t n) -{ - struct thread_info *need_step_over = NULL; - - if (debug_threads) - { - debug_enter (); - debug_printf ("linux_resume:\n"); - } - - for_each_thread ([&] (thread_info *thread) - { - linux_set_resume_request (thread, resume_info, n); - }); - - /* If there is a thread which would otherwise be resumed, which has - a pending status, then don't resume any threads - we can just - report the pending status. Make sure to queue any signals that - would otherwise be sent. In non-stop mode, we'll apply this - logic to each thread individually. We consume all pending events - before considering to start a step-over (in all-stop). */ - bool any_pending = false; - if (!non_stop) - any_pending = find_thread (resume_status_pending_p) != NULL; - - /* If there is a thread which would otherwise be resumed, which is - stopped at a breakpoint that needs stepping over, then don't - resume any threads - have it step over the breakpoint with all - other threads stopped, then resume all threads again. Make sure - to queue any signals that would otherwise be delivered or - queued. */ - if (!any_pending && supports_breakpoints ()) - need_step_over = find_thread (need_step_over_p); - - bool leave_all_stopped = (need_step_over != NULL || any_pending); - - if (debug_threads) - { - if (need_step_over != NULL) - debug_printf ("Not resuming all, need step over\n"); - else if (any_pending) - debug_printf ("Not resuming, all-stop and found " - "an LWP with pending status\n"); - else - debug_printf ("Resuming, no pending status or step over needed\n"); - } - - /* Even if we're leaving threads stopped, queue all signals we'd - otherwise deliver. */ - for_each_thread ([&] (thread_info *thread) - { - linux_resume_one_thread (thread, leave_all_stopped); - }); - - if (need_step_over) - start_step_over (get_thread_lwp (need_step_over)); - - if (debug_threads) - { - debug_printf ("linux_resume done\n"); - debug_exit (); - } - - /* We may have events that were pending that can/should be sent to - the client now. Trigger a linux_wait call. */ - if (target_is_async_p ()) - async_file_mark (); -} - -/* This function is called once per thread. We check the thread's - last resume request, which will tell us whether to resume, step, or - leave the thread stopped. Any signal the client requested to be - delivered has already been enqueued at this point. - - If any thread that GDB wants running is stopped at an internal - breakpoint that needs stepping over, we start a step-over operation - on that particular thread, and leave all others stopped. */ - -static void -proceed_one_lwp (thread_info *thread, lwp_info *except) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - int step; - - if (lwp == except) - return; - - if (debug_threads) - debug_printf ("proceed_one_lwp: lwp %ld\n", lwpid_of (thread)); - - if (!lwp->stopped) - { - if (debug_threads) - debug_printf (" LWP %ld already running\n", lwpid_of (thread)); - return; - } - - if (thread->last_resume_kind == resume_stop - && thread->last_status.kind != TARGET_WAITKIND_IGNORE) - { - if (debug_threads) - debug_printf (" client wants LWP to remain %ld stopped\n", - lwpid_of (thread)); - return; - } - - if (lwp->status_pending_p) - { - if (debug_threads) - debug_printf (" LWP %ld has pending status, leaving stopped\n", - lwpid_of (thread)); - return; - } - - gdb_assert (lwp->suspended >= 0); - - if (lwp->suspended) - { - if (debug_threads) - debug_printf (" LWP %ld is suspended\n", lwpid_of (thread)); - return; - } - - if (thread->last_resume_kind == resume_stop - && lwp->pending_signals_to_report == NULL - && (lwp->collecting_fast_tracepoint - == fast_tpoint_collect_result::not_collecting)) - { - /* We haven't reported this LWP as stopped yet (otherwise, the - last_status.kind check above would catch it, and we wouldn't - reach here. This LWP may have been momentarily paused by a - stop_all_lwps call while handling for example, another LWP's - step-over. In that case, the pending expected SIGSTOP signal - that was queued at vCont;t handling time will have already - been consumed by wait_for_sigstop, and so we need to requeue - another one here. Note that if the LWP already has a SIGSTOP - pending, this is a no-op. */ - - if (debug_threads) - debug_printf ("Client wants LWP %ld to stop. " - "Making sure it has a SIGSTOP pending\n", - lwpid_of (thread)); - - send_sigstop (lwp); - } - - if (thread->last_resume_kind == resume_step) - { - if (debug_threads) - debug_printf (" stepping LWP %ld, client wants it stepping\n", - lwpid_of (thread)); - - /* If resume_step is requested by GDB, install single-step - breakpoints when the thread is about to be actually resumed if - the single-step breakpoints weren't removed. */ - if (can_software_single_step () - && !has_single_step_breakpoints (thread)) - install_software_single_step_breakpoints (lwp); - - step = maybe_hw_step (thread); - } - else if (lwp->bp_reinsert != 0) - { - if (debug_threads) - debug_printf (" stepping LWP %ld, reinsert set\n", - lwpid_of (thread)); - - step = maybe_hw_step (thread); - } - else - step = 0; - - linux_resume_one_lwp (lwp, step, 0, NULL); -} - -static void -unsuspend_and_proceed_one_lwp (thread_info *thread, lwp_info *except) -{ - struct lwp_info *lwp = get_thread_lwp (thread); - - if (lwp == except) - return; - - lwp_suspended_decr (lwp); - - proceed_one_lwp (thread, except); -} - -/* When we finish a step-over, set threads running again. If there's - another thread that may need a step-over, now's the time to start - it. Eventually, we'll move all threads past their breakpoints. */ - -static void -proceed_all_lwps (void) -{ - struct thread_info *need_step_over; - - /* If there is a thread which would otherwise be resumed, which is - stopped at a breakpoint that needs stepping over, then don't - resume any threads - have it step over the breakpoint with all - other threads stopped, then resume all threads again. */ - - if (supports_breakpoints ()) - { - need_step_over = find_thread (need_step_over_p); - - if (need_step_over != NULL) - { - if (debug_threads) - debug_printf ("proceed_all_lwps: found " - "thread %ld needing a step-over\n", - lwpid_of (need_step_over)); - - start_step_over (get_thread_lwp (need_step_over)); - return; - } - } - - if (debug_threads) - debug_printf ("Proceeding, no step-over needed\n"); - - for_each_thread ([] (thread_info *thread) - { - proceed_one_lwp (thread, NULL); - }); -} - -/* Stopped LWPs that the client wanted to be running, that don't have - pending statuses, are set to run again, except for EXCEPT, if not - NULL. This undoes a stop_all_lwps call. */ - -static void -unstop_all_lwps (int unsuspend, struct lwp_info *except) -{ - if (debug_threads) - { - debug_enter (); - if (except) - debug_printf ("unstopping all lwps, except=(LWP %ld)\n", - lwpid_of (get_lwp_thread (except))); - else - debug_printf ("unstopping all lwps\n"); - } - - if (unsuspend) - for_each_thread ([&] (thread_info *thread) - { - unsuspend_and_proceed_one_lwp (thread, except); - }); - else - for_each_thread ([&] (thread_info *thread) - { - proceed_one_lwp (thread, except); - }); - - if (debug_threads) - { - debug_printf ("unstop_all_lwps done\n"); - debug_exit (); - } -} - - -#ifdef HAVE_LINUX_REGSETS - -#define use_linux_regsets 1 - -/* Returns true if REGSET has been disabled. */ - -static int -regset_disabled (struct regsets_info *info, struct regset_info *regset) -{ - return (info->disabled_regsets != NULL - && info->disabled_regsets[regset - info->regsets]); -} - -/* Disable REGSET. */ - -static void -disable_regset (struct regsets_info *info, struct regset_info *regset) -{ - int dr_offset; - - dr_offset = regset - info->regsets; - if (info->disabled_regsets == NULL) - info->disabled_regsets = (char *) xcalloc (1, info->num_regsets); - info->disabled_regsets[dr_offset] = 1; -} - -static int -regsets_fetch_inferior_registers (struct regsets_info *regsets_info, - struct regcache *regcache) -{ - struct regset_info *regset; - int saw_general_regs = 0; - int pid; - struct iovec iov; - - pid = lwpid_of (current_thread); - for (regset = regsets_info->regsets; regset->size >= 0; regset++) - { - void *buf, *data; - int nt_type, res; - - if (regset->size == 0 || regset_disabled (regsets_info, regset)) - continue; - - buf = xmalloc (regset->size); - - nt_type = regset->nt_type; - if (nt_type) - { - iov.iov_base = buf; - iov.iov_len = regset->size; - data = (void *) &iov; - } - else - data = buf; - -#ifndef __sparc__ - res = ptrace (regset->get_request, pid, - (PTRACE_TYPE_ARG3) (long) nt_type, data); -#else - res = ptrace (regset->get_request, pid, data, nt_type); -#endif - if (res < 0) - { - if (errno == EIO - || (errno == EINVAL && regset->type == OPTIONAL_REGS)) - { - /* If we get EIO on a regset, or an EINVAL and the regset is - optional, do not try it again for this process mode. */ - disable_regset (regsets_info, regset); - } - else if (errno == ENODATA) - { - /* ENODATA may be returned if the regset is currently - not "active". This can happen in normal operation, - so suppress the warning in this case. */ - } - else if (errno == ESRCH) - { - /* At this point, ESRCH should mean the process is - already gone, in which case we simply ignore attempts - to read its registers. */ - } - else - { - char s[256]; - sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d", - pid); - perror (s); - } - } - else - { - if (regset->type == GENERAL_REGS) - saw_general_regs = 1; - regset->store_function (regcache, buf); - } - free (buf); - } - if (saw_general_regs) - return 0; - else - return 1; -} - -static int -regsets_store_inferior_registers (struct regsets_info *regsets_info, - struct regcache *regcache) -{ - struct regset_info *regset; - int saw_general_regs = 0; - int pid; - struct iovec iov; - - pid = lwpid_of (current_thread); - for (regset = regsets_info->regsets; regset->size >= 0; regset++) - { - void *buf, *data; - int nt_type, res; - - if (regset->size == 0 || regset_disabled (regsets_info, regset) - || regset->fill_function == NULL) - continue; - - buf = xmalloc (regset->size); - - /* First fill the buffer with the current register set contents, - in case there are any items in the kernel's regset that are - not in gdbserver's regcache. */ - - nt_type = regset->nt_type; - if (nt_type) - { - iov.iov_base = buf; - iov.iov_len = regset->size; - data = (void *) &iov; - } - else - data = buf; - -#ifndef __sparc__ - res = ptrace (regset->get_request, pid, - (PTRACE_TYPE_ARG3) (long) nt_type, data); -#else - res = ptrace (regset->get_request, pid, data, nt_type); -#endif - - if (res == 0) - { - /* Then overlay our cached registers on that. */ - regset->fill_function (regcache, buf); - - /* Only now do we write the register set. */ -#ifndef __sparc__ - res = ptrace (regset->set_request, pid, - (PTRACE_TYPE_ARG3) (long) nt_type, data); -#else - res = ptrace (regset->set_request, pid, data, nt_type); -#endif - } - - if (res < 0) - { - if (errno == EIO - || (errno == EINVAL && regset->type == OPTIONAL_REGS)) - { - /* If we get EIO on a regset, or an EINVAL and the regset is - optional, do not try it again for this process mode. */ - disable_regset (regsets_info, regset); - } - else if (errno == ESRCH) - { - /* At this point, ESRCH should mean the process is - already gone, in which case we simply ignore attempts - to change its registers. See also the related - comment in linux_resume_one_lwp. */ - free (buf); - return 0; - } - else - { - perror ("Warning: ptrace(regsets_store_inferior_registers)"); - } - } - else if (regset->type == GENERAL_REGS) - saw_general_regs = 1; - free (buf); - } - if (saw_general_regs) - return 0; - else - return 1; -} - -#else /* !HAVE_LINUX_REGSETS */ - -#define use_linux_regsets 0 -#define regsets_fetch_inferior_registers(regsets_info, regcache) 1 -#define regsets_store_inferior_registers(regsets_info, regcache) 1 - -#endif - -/* Return 1 if register REGNO is supported by one of the regset ptrace - calls or 0 if it has to be transferred individually. */ - -static int -linux_register_in_regsets (const struct regs_info *regs_info, int regno) -{ - unsigned char mask = 1 << (regno % 8); - size_t index = regno / 8; - - return (use_linux_regsets - && (regs_info->regset_bitmap == NULL - || (regs_info->regset_bitmap[index] & mask) != 0)); -} - -#ifdef HAVE_LINUX_USRREGS - -static int -register_addr (const struct usrregs_info *usrregs, int regnum) -{ - int addr; - - if (regnum < 0 || regnum >= usrregs->num_regs) - error ("Invalid register number %d.", regnum); - - addr = usrregs->regmap[regnum]; - - return addr; -} - -/* Fetch one register. */ -static void -fetch_register (const struct usrregs_info *usrregs, - struct regcache *regcache, int regno) -{ - CORE_ADDR regaddr; - int i, size; - char *buf; - int pid; - - if (regno >= usrregs->num_regs) - return; - if ((*the_low_target.cannot_fetch_register) (regno)) - return; - - regaddr = register_addr (usrregs, regno); - if (regaddr == -1) - return; - - size = ((register_size (regcache->tdesc, regno) - + sizeof (PTRACE_XFER_TYPE) - 1) - & -sizeof (PTRACE_XFER_TYPE)); - buf = (char *) alloca (size); - - pid = lwpid_of (current_thread); - for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE)) - { - errno = 0; - *(PTRACE_XFER_TYPE *) (buf + i) = - ptrace (PTRACE_PEEKUSER, pid, - /* Coerce to a uintptr_t first to avoid potential gcc warning - of coercing an 8 byte integer to a 4 byte pointer. */ - (PTRACE_TYPE_ARG3) (uintptr_t) regaddr, (PTRACE_TYPE_ARG4) 0); - regaddr += sizeof (PTRACE_XFER_TYPE); - if (errno != 0) - { - /* Mark register REGNO unavailable. */ - supply_register (regcache, regno, NULL); - return; - } - } - - if (the_low_target.supply_ptrace_register) - the_low_target.supply_ptrace_register (regcache, regno, buf); - else - supply_register (regcache, regno, buf); -} - -/* Store one register. */ -static void -store_register (const struct usrregs_info *usrregs, - struct regcache *regcache, int regno) -{ - CORE_ADDR regaddr; - int i, size; - char *buf; - int pid; - - if (regno >= usrregs->num_regs) - return; - if ((*the_low_target.cannot_store_register) (regno)) - return; - - regaddr = register_addr (usrregs, regno); - if (regaddr == -1) - return; - - size = ((register_size (regcache->tdesc, regno) - + sizeof (PTRACE_XFER_TYPE) - 1) - & -sizeof (PTRACE_XFER_TYPE)); - buf = (char *) alloca (size); - memset (buf, 0, size); - - if (the_low_target.collect_ptrace_register) - the_low_target.collect_ptrace_register (regcache, regno, buf); - else - collect_register (regcache, regno, buf); - - pid = lwpid_of (current_thread); - for (i = 0; i < size; i += sizeof (PTRACE_XFER_TYPE)) - { - errno = 0; - ptrace (PTRACE_POKEUSER, pid, - /* Coerce to a uintptr_t first to avoid potential gcc warning - about coercing an 8 byte integer to a 4 byte pointer. */ - (PTRACE_TYPE_ARG3) (uintptr_t) regaddr, - (PTRACE_TYPE_ARG4) *(PTRACE_XFER_TYPE *) (buf + i)); - if (errno != 0) - { - /* At this point, ESRCH should mean the process is - already gone, in which case we simply ignore attempts - to change its registers. See also the related - comment in linux_resume_one_lwp. */ - if (errno == ESRCH) - return; - - if ((*the_low_target.cannot_store_register) (regno) == 0) - error ("writing register %d: %s", regno, safe_strerror (errno)); - } - regaddr += sizeof (PTRACE_XFER_TYPE); - } -} - -/* Fetch all registers, or just one, from the child process. - If REGNO is -1, do this for all registers, skipping any that are - assumed to have been retrieved by regsets_fetch_inferior_registers, - unless ALL is non-zero. - Otherwise, REGNO specifies which register (so we can save time). */ -static void -usr_fetch_inferior_registers (const struct regs_info *regs_info, - struct regcache *regcache, int regno, int all) -{ - struct usrregs_info *usr = regs_info->usrregs; - - if (regno == -1) - { - for (regno = 0; regno < usr->num_regs; regno++) - if (all || !linux_register_in_regsets (regs_info, regno)) - fetch_register (usr, regcache, regno); - } - else - fetch_register (usr, regcache, regno); -} - -/* Store our register values back into the inferior. - If REGNO is -1, do this for all registers, skipping any that are - assumed to have been saved by regsets_store_inferior_registers, - unless ALL is non-zero. - Otherwise, REGNO specifies which register (so we can save time). */ -static void -usr_store_inferior_registers (const struct regs_info *regs_info, - struct regcache *regcache, int regno, int all) -{ - struct usrregs_info *usr = regs_info->usrregs; - - if (regno == -1) - { - for (regno = 0; regno < usr->num_regs; regno++) - if (all || !linux_register_in_regsets (regs_info, regno)) - store_register (usr, regcache, regno); - } - else - store_register (usr, regcache, regno); -} - -#else /* !HAVE_LINUX_USRREGS */ - -#define usr_fetch_inferior_registers(regs_info, regcache, regno, all) do {} while (0) -#define usr_store_inferior_registers(regs_info, regcache, regno, all) do {} while (0) - -#endif - - -static void -linux_fetch_registers (struct regcache *regcache, int regno) -{ - int use_regsets; - int all = 0; - const struct regs_info *regs_info = (*the_low_target.regs_info) (); - - if (regno == -1) - { - if (the_low_target.fetch_register != NULL - && regs_info->usrregs != NULL) - for (regno = 0; regno < regs_info->usrregs->num_regs; regno++) - (*the_low_target.fetch_register) (regcache, regno); - - all = regsets_fetch_inferior_registers (regs_info->regsets_info, regcache); - if (regs_info->usrregs != NULL) - usr_fetch_inferior_registers (regs_info, regcache, -1, all); - } - else - { - if (the_low_target.fetch_register != NULL - && (*the_low_target.fetch_register) (regcache, regno)) - return; - - use_regsets = linux_register_in_regsets (regs_info, regno); - if (use_regsets) - all = regsets_fetch_inferior_registers (regs_info->regsets_info, - regcache); - if ((!use_regsets || all) && regs_info->usrregs != NULL) - usr_fetch_inferior_registers (regs_info, regcache, regno, 1); - } -} - -static void -linux_store_registers (struct regcache *regcache, int regno) -{ - int use_regsets; - int all = 0; - const struct regs_info *regs_info = (*the_low_target.regs_info) (); - - if (regno == -1) - { - all = regsets_store_inferior_registers (regs_info->regsets_info, - regcache); - if (regs_info->usrregs != NULL) - usr_store_inferior_registers (regs_info, regcache, regno, all); - } - else - { - use_regsets = linux_register_in_regsets (regs_info, regno); - if (use_regsets) - all = regsets_store_inferior_registers (regs_info->regsets_info, - regcache); - if ((!use_regsets || all) && regs_info->usrregs != NULL) - usr_store_inferior_registers (regs_info, regcache, regno, 1); - } -} - - -/* Copy LEN bytes from inferior's memory starting at MEMADDR - to debugger memory starting at MYADDR. */ - -static int -linux_read_memory (CORE_ADDR memaddr, unsigned char *myaddr, int len) -{ - int pid = lwpid_of (current_thread); - PTRACE_XFER_TYPE *buffer; - CORE_ADDR addr; - int count; - char filename[64]; - int i; - int ret; - int fd; - - /* Try using /proc. Don't bother for one word. */ - if (len >= 3 * sizeof (long)) - { - int bytes; - - /* We could keep this file open and cache it - possibly one per - thread. That requires some juggling, but is even faster. */ - sprintf (filename, "/proc/%d/mem", pid); - fd = open (filename, O_RDONLY | O_LARGEFILE); - if (fd == -1) - goto no_proc; - - /* If pread64 is available, use it. It's faster if the kernel - supports it (only one syscall), and it's 64-bit safe even on - 32-bit platforms (for instance, SPARC debugging a SPARC64 - application). */ -#ifdef HAVE_PREAD64 - bytes = pread64 (fd, myaddr, len, memaddr); -#else - bytes = -1; - if (lseek (fd, memaddr, SEEK_SET) != -1) - bytes = read (fd, myaddr, len); -#endif - - close (fd); - if (bytes == len) - return 0; - - /* Some data was read, we'll try to get the rest with ptrace. */ - if (bytes > 0) - { - memaddr += bytes; - myaddr += bytes; - len -= bytes; - } - } - - no_proc: - /* Round starting address down to longword boundary. */ - addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); - /* Round ending address up; get number of longwords that makes. */ - count = ((((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) - / sizeof (PTRACE_XFER_TYPE)); - /* Allocate buffer of that many longwords. */ - buffer = XALLOCAVEC (PTRACE_XFER_TYPE, count); - - /* Read all the longwords */ - errno = 0; - for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) - { - /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning - about coercing an 8 byte integer to a 4 byte pointer. */ - buffer[i] = ptrace (PTRACE_PEEKTEXT, pid, - (PTRACE_TYPE_ARG3) (uintptr_t) addr, - (PTRACE_TYPE_ARG4) 0); - if (errno) - break; - } - ret = errno; - - /* Copy appropriate bytes out of the buffer. */ - if (i > 0) - { - i *= sizeof (PTRACE_XFER_TYPE); - i -= memaddr & (sizeof (PTRACE_XFER_TYPE) - 1); - memcpy (myaddr, - (char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), - i < len ? i : len); - } - - return ret; -} - -/* Copy LEN bytes of data from debugger memory at MYADDR to inferior's - memory at MEMADDR. On failure (cannot write to the inferior) - returns the value of errno. Always succeeds if LEN is zero. */ - -static int -linux_write_memory (CORE_ADDR memaddr, const unsigned char *myaddr, int len) -{ - int i; - /* Round starting address down to longword boundary. */ - CORE_ADDR addr = memaddr & -(CORE_ADDR) sizeof (PTRACE_XFER_TYPE); - /* Round ending address up; get number of longwords that makes. */ - int count - = (((memaddr + len) - addr) + sizeof (PTRACE_XFER_TYPE) - 1) - / sizeof (PTRACE_XFER_TYPE); - - /* Allocate buffer of that many longwords. */ - PTRACE_XFER_TYPE *buffer = XALLOCAVEC (PTRACE_XFER_TYPE, count); - - int pid = lwpid_of (current_thread); - - if (len == 0) - { - /* Zero length write always succeeds. */ - return 0; - } - - if (debug_threads) - { - /* Dump up to four bytes. */ - char str[4 * 2 + 1]; - char *p = str; - int dump = len < 4 ? len : 4; - - for (i = 0; i < dump; i++) - { - sprintf (p, "%02x", myaddr[i]); - p += 2; - } - *p = '\0'; - - debug_printf ("Writing %s to 0x%08lx in process %d\n", - str, (long) memaddr, pid); - } - - /* Fill start and end extra bytes of buffer with existing memory data. */ - - errno = 0; - /* Coerce the 3rd arg to a uintptr_t first to avoid potential gcc warning - about coercing an 8 byte integer to a 4 byte pointer. */ - buffer[0] = ptrace (PTRACE_PEEKTEXT, pid, - (PTRACE_TYPE_ARG3) (uintptr_t) addr, - (PTRACE_TYPE_ARG4) 0); - if (errno) - return errno; - - if (count > 1) - { - errno = 0; - buffer[count - 1] - = ptrace (PTRACE_PEEKTEXT, pid, - /* Coerce to a uintptr_t first to avoid potential gcc warning - about coercing an 8 byte integer to a 4 byte pointer. */ - (PTRACE_TYPE_ARG3) (uintptr_t) (addr + (count - 1) - * sizeof (PTRACE_XFER_TYPE)), - (PTRACE_TYPE_ARG4) 0); - if (errno) - return errno; - } - - /* Copy data to be written over corresponding part of buffer. */ - - memcpy ((char *) buffer + (memaddr & (sizeof (PTRACE_XFER_TYPE) - 1)), - myaddr, len); - - /* Write the entire buffer. */ - - for (i = 0; i < count; i++, addr += sizeof (PTRACE_XFER_TYPE)) - { - errno = 0; - ptrace (PTRACE_POKETEXT, pid, - /* Coerce to a uintptr_t first to avoid potential gcc warning - about coercing an 8 byte integer to a 4 byte pointer. */ - (PTRACE_TYPE_ARG3) (uintptr_t) addr, - (PTRACE_TYPE_ARG4) buffer[i]); - if (errno) - return errno; - } - - return 0; -} - -static void -linux_look_up_symbols (void) -{ -#ifdef USE_THREAD_DB - struct process_info *proc = current_process (); - - if (proc->priv->thread_db != NULL) - return; - - thread_db_init (); -#endif -} - -static void -linux_request_interrupt (void) -{ - /* Send a SIGINT to the process group. This acts just like the user - typed a ^C on the controlling terminal. */ - kill (-signal_pid, SIGINT); -} - -/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET - to debugger memory starting at MYADDR. */ - -static int -linux_read_auxv (CORE_ADDR offset, unsigned char *myaddr, unsigned int len) -{ - char filename[PATH_MAX]; - int fd, n; - int pid = lwpid_of (current_thread); - - xsnprintf (filename, sizeof filename, "/proc/%d/auxv", pid); - - fd = open (filename, O_RDONLY); - if (fd < 0) - return -1; - - if (offset != (CORE_ADDR) 0 - && lseek (fd, (off_t) offset, SEEK_SET) != (off_t) offset) - n = -1; - else - n = read (fd, myaddr, len); - - close (fd); - - return n; -} - -/* These breakpoint and watchpoint related wrapper functions simply - pass on the function call if the target has registered a - corresponding function. */ - -static int -linux_supports_z_point_type (char z_type) -{ - return (the_low_target.supports_z_point_type != NULL - && the_low_target.supports_z_point_type (z_type)); -} - -static int -linux_insert_point (enum raw_bkpt_type type, CORE_ADDR addr, - int size, struct raw_breakpoint *bp) -{ - if (type == raw_bkpt_type_sw) - return insert_memory_breakpoint (bp); - else if (the_low_target.insert_point != NULL) - return the_low_target.insert_point (type, addr, size, bp); - else - /* Unsupported (see target.h). */ - return 1; -} - -static int -linux_remove_point (enum raw_bkpt_type type, CORE_ADDR addr, - int size, struct raw_breakpoint *bp) -{ - if (type == raw_bkpt_type_sw) - return remove_memory_breakpoint (bp); - else if (the_low_target.remove_point != NULL) - return the_low_target.remove_point (type, addr, size, bp); - else - /* Unsupported (see target.h). */ - return 1; -} - -/* Implement the to_stopped_by_sw_breakpoint target_ops - method. */ - -static int -linux_stopped_by_sw_breakpoint (void) -{ - struct lwp_info *lwp = get_thread_lwp (current_thread); - - return (lwp->stop_reason == TARGET_STOPPED_BY_SW_BREAKPOINT); -} - -/* Implement the to_supports_stopped_by_sw_breakpoint target_ops - method. */ - -static int -linux_supports_stopped_by_sw_breakpoint (void) -{ - return USE_SIGTRAP_SIGINFO; -} - -/* Implement the to_stopped_by_hw_breakpoint target_ops - method. */ - -static int -linux_stopped_by_hw_breakpoint (void) -{ - struct lwp_info *lwp = get_thread_lwp (current_thread); - - return (lwp->stop_reason == TARGET_STOPPED_BY_HW_BREAKPOINT); -} - -/* Implement the to_supports_stopped_by_hw_breakpoint target_ops - method. */ - -static int -linux_supports_stopped_by_hw_breakpoint (void) -{ - return USE_SIGTRAP_SIGINFO; -} - -/* Implement the supports_hardware_single_step target_ops method. */ - -static int -linux_supports_hardware_single_step (void) -{ - return can_hardware_single_step (); -} - -static int -linux_supports_software_single_step (void) -{ - return can_software_single_step (); -} - -static int -linux_stopped_by_watchpoint (void) -{ - struct lwp_info *lwp = get_thread_lwp (current_thread); - - return lwp->stop_reason == TARGET_STOPPED_BY_WATCHPOINT; -} - -static CORE_ADDR -linux_stopped_data_address (void) -{ - struct lwp_info *lwp = get_thread_lwp (current_thread); - - return lwp->stopped_data_address; -} - -#if defined(__UCLIBC__) && defined(HAS_NOMMU) \ - && defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) \ - && defined(PT_TEXT_END_ADDR) - -/* This is only used for targets that define PT_TEXT_ADDR, - PT_DATA_ADDR and PT_TEXT_END_ADDR. If those are not defined, supposedly - the target has different ways of acquiring this information, like - loadmaps. */ - -/* Under uClinux, programs are loaded at non-zero offsets, which we need - to tell gdb about. */ - -static int -linux_read_offsets (CORE_ADDR *text_p, CORE_ADDR *data_p) -{ - unsigned long text, text_end, data; - int pid = lwpid_of (current_thread); - - errno = 0; - - text = ptrace (PTRACE_PEEKUSER, pid, (PTRACE_TYPE_ARG3) PT_TEXT_ADDR, - (PTRACE_TYPE_ARG4) 0); - text_end = ptrace (PTRACE_PEEKUSER, pid, (PTRACE_TYPE_ARG3) PT_TEXT_END_ADDR, - (PTRACE_TYPE_ARG4) 0); - data = ptrace (PTRACE_PEEKUSER, pid, (PTRACE_TYPE_ARG3) PT_DATA_ADDR, - (PTRACE_TYPE_ARG4) 0); - - if (errno == 0) - { - /* Both text and data offsets produced at compile-time (and so - used by gdb) are relative to the beginning of the program, - with the data segment immediately following the text segment. - However, the actual runtime layout in memory may put the data - somewhere else, so when we send gdb a data base-address, we - use the real data base address and subtract the compile-time - data base-address from it (which is just the length of the - text segment). BSS immediately follows data in both - cases. */ - *text_p = text; - *data_p = data - (text_end - text); - - return 1; - } - return 0; -} -#endif - -static int -linux_qxfer_osdata (const char *annex, - unsigned char *readbuf, unsigned const char *writebuf, - CORE_ADDR offset, int len) -{ - return linux_common_xfer_osdata (annex, readbuf, offset, len); -} - -/* Convert a native/host siginfo object, into/from the siginfo in the - layout of the inferiors' architecture. */ - -static void -siginfo_fixup (siginfo_t *siginfo, gdb_byte *inf_siginfo, int direction) -{ - int done = 0; - - if (the_low_target.siginfo_fixup != NULL) - done = the_low_target.siginfo_fixup (siginfo, inf_siginfo, direction); - - /* If there was no callback, or the callback didn't do anything, - then just do a straight memcpy. */ - if (!done) - { - if (direction == 1) - memcpy (siginfo, inf_siginfo, sizeof (siginfo_t)); - else - memcpy (inf_siginfo, siginfo, sizeof (siginfo_t)); - } -} - -static int -linux_xfer_siginfo (const char *annex, unsigned char *readbuf, - unsigned const char *writebuf, CORE_ADDR offset, int len) -{ - int pid; - siginfo_t siginfo; - gdb_byte inf_siginfo[sizeof (siginfo_t)]; - - if (current_thread == NULL) - return -1; - - pid = lwpid_of (current_thread); - - if (debug_threads) - debug_printf ("%s siginfo for lwp %d.\n", - readbuf != NULL ? "Reading" : "Writing", - pid); - - if (offset >= sizeof (siginfo)) - return -1; - - if (ptrace (PTRACE_GETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo) != 0) - return -1; - - /* When GDBSERVER is built as a 64-bit application, ptrace writes into - SIGINFO an object with 64-bit layout. Since debugging a 32-bit - inferior with a 64-bit GDBSERVER should look the same as debugging it - with a 32-bit GDBSERVER, we need to convert it. */ - siginfo_fixup (&siginfo, inf_siginfo, 0); - - if (offset + len > sizeof (siginfo)) - len = sizeof (siginfo) - offset; - - if (readbuf != NULL) - memcpy (readbuf, inf_siginfo + offset, len); - else - { - memcpy (inf_siginfo + offset, writebuf, len); - - /* Convert back to ptrace layout before flushing it out. */ - siginfo_fixup (&siginfo, inf_siginfo, 1); - - if (ptrace (PTRACE_SETSIGINFO, pid, (PTRACE_TYPE_ARG3) 0, &siginfo) != 0) - return -1; - } - - return len; -} - -/* SIGCHLD handler that serves two purposes: In non-stop/async mode, - so we notice when children change state; as the handler for the - sigsuspend in my_waitpid. */ - -static void -sigchld_handler (int signo) -{ - int old_errno = errno; - - if (debug_threads) - { - do - { - /* Use the async signal safe debug function. */ - if (debug_write ("sigchld_handler\n", - sizeof ("sigchld_handler\n") - 1) < 0) - break; /* just ignore */ - } while (0); - } - - if (target_is_async_p ()) - async_file_mark (); /* trigger a linux_wait */ - - errno = old_errno; -} - -static int -linux_supports_non_stop (void) -{ - return 1; -} - -static int -linux_async (int enable) -{ - int previous = target_is_async_p (); - - if (debug_threads) - debug_printf ("linux_async (%d), previous=%d\n", - enable, previous); - - if (previous != enable) - { - sigset_t mask; - sigemptyset (&mask); - sigaddset (&mask, SIGCHLD); - - gdb_sigmask (SIG_BLOCK, &mask, NULL); - - if (enable) - { - if (pipe (linux_event_pipe) == -1) - { - linux_event_pipe[0] = -1; - linux_event_pipe[1] = -1; - gdb_sigmask (SIG_UNBLOCK, &mask, NULL); - - warning ("creating event pipe failed."); - return previous; - } - - fcntl (linux_event_pipe[0], F_SETFL, O_NONBLOCK); - fcntl (linux_event_pipe[1], F_SETFL, O_NONBLOCK); - - /* Register the event loop handler. */ - add_file_handler (linux_event_pipe[0], - handle_target_event, NULL); - - /* Always trigger a linux_wait. */ - async_file_mark (); - } - else - { - delete_file_handler (linux_event_pipe[0]); - - close (linux_event_pipe[0]); - close (linux_event_pipe[1]); - linux_event_pipe[0] = -1; - linux_event_pipe[1] = -1; - } - - gdb_sigmask (SIG_UNBLOCK, &mask, NULL); - } - - return previous; -} - -static int -linux_start_non_stop (int nonstop) -{ - /* Register or unregister from event-loop accordingly. */ - linux_async (nonstop); - - if (target_is_async_p () != (nonstop != 0)) - return -1; - - return 0; -} - -static int -linux_supports_multi_process (void) -{ - return 1; -} - -/* Check if fork events are supported. */ - -static int -linux_supports_fork_events (void) -{ - return linux_supports_tracefork (); -} - -/* Check if vfork events are supported. */ - -static int -linux_supports_vfork_events (void) -{ - return linux_supports_tracefork (); -} - -/* Check if exec events are supported. */ - -static int -linux_supports_exec_events (void) -{ - return linux_supports_traceexec (); -} - -/* Target hook for 'handle_new_gdb_connection'. Causes a reset of the - ptrace flags for all inferiors. This is in case the new GDB connection - doesn't support the same set of events that the previous one did. */ - -static void -linux_handle_new_gdb_connection (void) -{ - /* Request that all the lwps reset their ptrace options. */ - for_each_thread ([] (thread_info *thread) - { - struct lwp_info *lwp = get_thread_lwp (thread); - - if (!lwp->stopped) - { - /* Stop the lwp so we can modify its ptrace options. */ - lwp->must_set_ptrace_flags = 1; - linux_stop_lwp (lwp); - } - else - { - /* Already stopped; go ahead and set the ptrace options. */ - struct process_info *proc = find_process_pid (pid_of (thread)); - int options = linux_low_ptrace_options (proc->attached); - - linux_enable_event_reporting (lwpid_of (thread), options); - lwp->must_set_ptrace_flags = 0; - } - }); -} - -static int -linux_supports_disable_randomization (void) -{ -#ifdef HAVE_PERSONALITY - return 1; -#else - return 0; -#endif -} - -static int -linux_supports_agent (void) -{ - return 1; -} - -static int -linux_supports_range_stepping (void) -{ - if (can_software_single_step ()) - return 1; - if (*the_low_target.supports_range_stepping == NULL) - return 0; - - return (*the_low_target.supports_range_stepping) (); -} - -#if defined PT_GETDSBT || defined PTRACE_GETFDPIC -struct target_loadseg -{ - /* Core address to which the segment is mapped. */ - Elf32_Addr addr; - /* VMA recorded in the program header. */ - Elf32_Addr p_vaddr; - /* Size of this segment in memory. */ - Elf32_Word p_memsz; -}; - -# if defined PT_GETDSBT -struct target_loadmap -{ - /* Protocol version number, must be zero. */ - Elf32_Word version; - /* Pointer to the DSBT table, its size, and the DSBT index. */ - unsigned *dsbt_table; - unsigned dsbt_size, dsbt_index; - /* Number of segments in this map. */ - Elf32_Word nsegs; - /* The actual memory map. */ - struct target_loadseg segs[/*nsegs*/]; -}; -# define LINUX_LOADMAP PT_GETDSBT -# define LINUX_LOADMAP_EXEC PTRACE_GETDSBT_EXEC -# define LINUX_LOADMAP_INTERP PTRACE_GETDSBT_INTERP -# else -struct target_loadmap -{ - /* Protocol version number, must be zero. */ - Elf32_Half version; - /* Number of segments in this map. */ - Elf32_Half nsegs; - /* The actual memory map. */ - struct target_loadseg segs[/*nsegs*/]; -}; -# define LINUX_LOADMAP PTRACE_GETFDPIC -# define LINUX_LOADMAP_EXEC PTRACE_GETFDPIC_EXEC -# define LINUX_LOADMAP_INTERP PTRACE_GETFDPIC_INTERP -# endif - -static int -linux_read_loadmap (const char *annex, CORE_ADDR offset, - unsigned char *myaddr, unsigned int len) -{ - int pid = lwpid_of (current_thread); - int addr = -1; - struct target_loadmap *data = NULL; - unsigned int actual_length, copy_length; - - if (strcmp (annex, "exec") == 0) - addr = (int) LINUX_LOADMAP_EXEC; - else if (strcmp (annex, "interp") == 0) - addr = (int) LINUX_LOADMAP_INTERP; - else - return -1; - - if (ptrace (LINUX_LOADMAP, pid, addr, &data) != 0) - return -1; - - if (data == NULL) - return -1; - - actual_length = sizeof (struct target_loadmap) - + sizeof (struct target_loadseg) * data->nsegs; - - if (offset < 0 || offset > actual_length) - return -1; - - copy_length = actual_length - offset < len ? actual_length - offset : len; - memcpy (myaddr, (char *) data + offset, copy_length); - return copy_length; -} -#else -# define linux_read_loadmap NULL -#endif /* defined PT_GETDSBT || defined PTRACE_GETFDPIC */ - -static void -linux_process_qsupported (char **features, int count) -{ - if (the_low_target.process_qsupported != NULL) - the_low_target.process_qsupported (features, count); -} - -static int -linux_supports_catch_syscall (void) -{ - return (the_low_target.get_syscall_trapinfo != NULL - && linux_supports_tracesysgood ()); -} - -static int -linux_get_ipa_tdesc_idx (void) -{ - if (the_low_target.get_ipa_tdesc_idx == NULL) - return 0; - - return (*the_low_target.get_ipa_tdesc_idx) (); -} - -static int -linux_supports_tracepoints (void) -{ - if (*the_low_target.supports_tracepoints == NULL) - return 0; - - return (*the_low_target.supports_tracepoints) (); -} - -static CORE_ADDR -linux_read_pc (struct regcache *regcache) -{ - if (the_low_target.get_pc == NULL) - return 0; - - return (*the_low_target.get_pc) (regcache); -} - -static void -linux_write_pc (struct regcache *regcache, CORE_ADDR pc) -{ - gdb_assert (the_low_target.set_pc != NULL); - - (*the_low_target.set_pc) (regcache, pc); -} - -static int -linux_thread_stopped (struct thread_info *thread) -{ - return get_thread_lwp (thread)->stopped; -} - -/* This exposes stop-all-threads functionality to other modules. */ - -static void -linux_pause_all (int freeze) -{ - stop_all_lwps (freeze, NULL); -} - -/* This exposes unstop-all-threads functionality to other gdbserver - modules. */ - -static void -linux_unpause_all (int unfreeze) -{ - unstop_all_lwps (unfreeze, NULL); -} - -static int -linux_prepare_to_access_memory (void) -{ - /* Neither ptrace nor /proc/PID/mem allow accessing memory through a - running LWP. */ - if (non_stop) - linux_pause_all (1); - return 0; -} - -static void -linux_done_accessing_memory (void) -{ - /* Neither ptrace nor /proc/PID/mem allow accessing memory through a - running LWP. */ - if (non_stop) - linux_unpause_all (1); -} - -static int -linux_install_fast_tracepoint_jump_pad (CORE_ADDR tpoint, CORE_ADDR tpaddr, - CORE_ADDR collector, - CORE_ADDR lockaddr, - ULONGEST orig_size, - CORE_ADDR *jump_entry, - CORE_ADDR *trampoline, - ULONGEST *trampoline_size, - unsigned char *jjump_pad_insn, - ULONGEST *jjump_pad_insn_size, - CORE_ADDR *adjusted_insn_addr, - CORE_ADDR *adjusted_insn_addr_end, - char *err) -{ - return (*the_low_target.install_fast_tracepoint_jump_pad) - (tpoint, tpaddr, collector, lockaddr, orig_size, - jump_entry, trampoline, trampoline_size, - jjump_pad_insn, jjump_pad_insn_size, - adjusted_insn_addr, adjusted_insn_addr_end, - err); -} - -static struct emit_ops * -linux_emit_ops (void) -{ - if (the_low_target.emit_ops != NULL) - return (*the_low_target.emit_ops) (); - else - return NULL; -} - -static int -linux_get_min_fast_tracepoint_insn_len (void) -{ - return (*the_low_target.get_min_fast_tracepoint_insn_len) (); -} - -/* Extract &phdr and num_phdr in the inferior. Return 0 on success. */ - -static int -get_phdr_phnum_from_proc_auxv (const int pid, const int is_elf64, - CORE_ADDR *phdr_memaddr, int *num_phdr) -{ - char filename[PATH_MAX]; - int fd; - const int auxv_size = is_elf64 - ? sizeof (Elf64_auxv_t) : sizeof (Elf32_auxv_t); - char buf[sizeof (Elf64_auxv_t)]; /* The larger of the two. */ - - xsnprintf (filename, sizeof filename, "/proc/%d/auxv", pid); - - fd = open (filename, O_RDONLY); - if (fd < 0) - return 1; - - *phdr_memaddr = 0; - *num_phdr = 0; - while (read (fd, buf, auxv_size) == auxv_size - && (*phdr_memaddr == 0 || *num_phdr == 0)) - { - if (is_elf64) - { - Elf64_auxv_t *const aux = (Elf64_auxv_t *) buf; - - switch (aux->a_type) - { - case AT_PHDR: - *phdr_memaddr = aux->a_un.a_val; - break; - case AT_PHNUM: - *num_phdr = aux->a_un.a_val; - break; - } - } - else - { - Elf32_auxv_t *const aux = (Elf32_auxv_t *) buf; - - switch (aux->a_type) - { - case AT_PHDR: - *phdr_memaddr = aux->a_un.a_val; - break; - case AT_PHNUM: - *num_phdr = aux->a_un.a_val; - break; - } - } - } - - close (fd); - - if (*phdr_memaddr == 0 || *num_phdr == 0) - { - warning ("Unexpected missing AT_PHDR and/or AT_PHNUM: " - "phdr_memaddr = %ld, phdr_num = %d", - (long) *phdr_memaddr, *num_phdr); - return 2; - } - - return 0; -} - -/* Return &_DYNAMIC (via PT_DYNAMIC) in the inferior, or 0 if not present. */ - -static CORE_ADDR -get_dynamic (const int pid, const int is_elf64) -{ - CORE_ADDR phdr_memaddr, relocation; - int num_phdr, i; - unsigned char *phdr_buf; - const int phdr_size = is_elf64 ? sizeof (Elf64_Phdr) : sizeof (Elf32_Phdr); - - if (get_phdr_phnum_from_proc_auxv (pid, is_elf64, &phdr_memaddr, &num_phdr)) - return 0; - - gdb_assert (num_phdr < 100); /* Basic sanity check. */ - phdr_buf = (unsigned char *) alloca (num_phdr * phdr_size); - - if (linux_read_memory (phdr_memaddr, phdr_buf, num_phdr * phdr_size)) - return 0; - - /* Compute relocation: it is expected to be 0 for "regular" executables, - non-zero for PIE ones. */ - relocation = -1; - for (i = 0; relocation == -1 && i < num_phdr; i++) - if (is_elf64) - { - Elf64_Phdr *const p = (Elf64_Phdr *) (phdr_buf + i * phdr_size); - - if (p->p_type == PT_PHDR) - relocation = phdr_memaddr - p->p_vaddr; - } - else - { - Elf32_Phdr *const p = (Elf32_Phdr *) (phdr_buf + i * phdr_size); - - if (p->p_type == PT_PHDR) - relocation = phdr_memaddr - p->p_vaddr; - } - - if (relocation == -1) - { - /* PT_PHDR is optional, but necessary for PIE in general. Fortunately - any real world executables, including PIE executables, have always - PT_PHDR present. PT_PHDR is not present in some shared libraries or - in fpc (Free Pascal 2.4) binaries but neither of those have a need for - or present DT_DEBUG anyway (fpc binaries are statically linked). - - Therefore if there exists DT_DEBUG there is always also PT_PHDR. - - GDB could find RELOCATION also from AT_ENTRY - e_entry. */ - - return 0; - } - - for (i = 0; i < num_phdr; i++) - { - if (is_elf64) - { - Elf64_Phdr *const p = (Elf64_Phdr *) (phdr_buf + i * phdr_size); - - if (p->p_type == PT_DYNAMIC) - return p->p_vaddr + relocation; - } - else - { - Elf32_Phdr *const p = (Elf32_Phdr *) (phdr_buf + i * phdr_size); - - if (p->p_type == PT_DYNAMIC) - return p->p_vaddr + relocation; - } - } - - return 0; -} - -/* Return &_r_debug in the inferior, or -1 if not present. Return value - can be 0 if the inferior does not yet have the library list initialized. - We look for DT_MIPS_RLD_MAP first. MIPS executables use this instead of - DT_DEBUG, although they sometimes contain an unused DT_DEBUG entry too. */ - -static CORE_ADDR -get_r_debug (const int pid, const int is_elf64) -{ - CORE_ADDR dynamic_memaddr; - const int dyn_size = is_elf64 ? sizeof (Elf64_Dyn) : sizeof (Elf32_Dyn); - unsigned char buf[sizeof (Elf64_Dyn)]; /* The larger of the two. */ - CORE_ADDR map = -1; - - dynamic_memaddr = get_dynamic (pid, is_elf64); - if (dynamic_memaddr == 0) - return map; - - while (linux_read_memory (dynamic_memaddr, buf, dyn_size) == 0) - { - if (is_elf64) - { - Elf64_Dyn *const dyn = (Elf64_Dyn *) buf; -#if defined DT_MIPS_RLD_MAP || defined DT_MIPS_RLD_MAP_REL - union - { - Elf64_Xword map; - unsigned char buf[sizeof (Elf64_Xword)]; - } - rld_map; -#endif -#ifdef DT_MIPS_RLD_MAP - if (dyn->d_tag == DT_MIPS_RLD_MAP) - { - if (linux_read_memory (dyn->d_un.d_val, - rld_map.buf, sizeof (rld_map.buf)) == 0) - return rld_map.map; - else - break; - } -#endif /* DT_MIPS_RLD_MAP */ -#ifdef DT_MIPS_RLD_MAP_REL - if (dyn->d_tag == DT_MIPS_RLD_MAP_REL) - { - if (linux_read_memory (dyn->d_un.d_val + dynamic_memaddr, - rld_map.buf, sizeof (rld_map.buf)) == 0) - return rld_map.map; - else - break; - } -#endif /* DT_MIPS_RLD_MAP_REL */ - - if (dyn->d_tag == DT_DEBUG && map == -1) - map = dyn->d_un.d_val; - - if (dyn->d_tag == DT_NULL) - break; - } - else - { - Elf32_Dyn *const dyn = (Elf32_Dyn *) buf; -#if defined DT_MIPS_RLD_MAP || defined DT_MIPS_RLD_MAP_REL - union - { - Elf32_Word map; - unsigned char buf[sizeof (Elf32_Word)]; - } - rld_map; -#endif -#ifdef DT_MIPS_RLD_MAP - if (dyn->d_tag == DT_MIPS_RLD_MAP) - { - if (linux_read_memory (dyn->d_un.d_val, - rld_map.buf, sizeof (rld_map.buf)) == 0) - return rld_map.map; - else - break; - } -#endif /* DT_MIPS_RLD_MAP */ -#ifdef DT_MIPS_RLD_MAP_REL - if (dyn->d_tag == DT_MIPS_RLD_MAP_REL) - { - if (linux_read_memory (dyn->d_un.d_val + dynamic_memaddr, - rld_map.buf, sizeof (rld_map.buf)) == 0) - return rld_map.map; - else - break; - } -#endif /* DT_MIPS_RLD_MAP_REL */ - - if (dyn->d_tag == DT_DEBUG && map == -1) - map = dyn->d_un.d_val; - - if (dyn->d_tag == DT_NULL) - break; - } - - dynamic_memaddr += dyn_size; - } - - return map; -} - -/* Read one pointer from MEMADDR in the inferior. */ - -static int -read_one_ptr (CORE_ADDR memaddr, CORE_ADDR *ptr, int ptr_size) -{ - int ret; - - /* Go through a union so this works on either big or little endian - hosts, when the inferior's pointer size is smaller than the size - of CORE_ADDR. It is assumed the inferior's endianness is the - same of the superior's. */ - union - { - CORE_ADDR core_addr; - unsigned int ui; - unsigned char uc; - } addr; - - ret = linux_read_memory (memaddr, &addr.uc, ptr_size); - if (ret == 0) - { - if (ptr_size == sizeof (CORE_ADDR)) - *ptr = addr.core_addr; - else if (ptr_size == sizeof (unsigned int)) - *ptr = addr.ui; - else - gdb_assert_not_reached ("unhandled pointer size"); - } - return ret; -} - -struct link_map_offsets - { - /* Offset and size of r_debug.r_version. */ - int r_version_offset; - - /* Offset and size of r_debug.r_map. */ - int r_map_offset; - - /* Offset to l_addr field in struct link_map. */ - int l_addr_offset; - - /* Offset to l_name field in struct link_map. */ - int l_name_offset; - - /* Offset to l_ld field in struct link_map. */ - int l_ld_offset; - - /* Offset to l_next field in struct link_map. */ - int l_next_offset; - - /* Offset to l_prev field in struct link_map. */ - int l_prev_offset; - }; - -/* Construct qXfer:libraries-svr4:read reply. */ - -static int -linux_qxfer_libraries_svr4 (const char *annex, unsigned char *readbuf, - unsigned const char *writebuf, - CORE_ADDR offset, int len) -{ - struct process_info_private *const priv = current_process ()->priv; - char filename[PATH_MAX]; - int pid, is_elf64; - - static const struct link_map_offsets lmo_32bit_offsets = - { - 0, /* r_version offset. */ - 4, /* r_debug.r_map offset. */ - 0, /* l_addr offset in link_map. */ - 4, /* l_name offset in link_map. */ - 8, /* l_ld offset in link_map. */ - 12, /* l_next offset in link_map. */ - 16 /* l_prev offset in link_map. */ - }; - - static const struct link_map_offsets lmo_64bit_offsets = - { - 0, /* r_version offset. */ - 8, /* r_debug.r_map offset. */ - 0, /* l_addr offset in link_map. */ - 8, /* l_name offset in link_map. */ - 16, /* l_ld offset in link_map. */ - 24, /* l_next offset in link_map. */ - 32 /* l_prev offset in link_map. */ - }; - const struct link_map_offsets *lmo; - unsigned int machine; - int ptr_size; - CORE_ADDR lm_addr = 0, lm_prev = 0; - CORE_ADDR l_name, l_addr, l_ld, l_next, l_prev; - int header_done = 0; - - if (writebuf != NULL) - return -2; - if (readbuf == NULL) - return -1; - - pid = lwpid_of (current_thread); - xsnprintf (filename, sizeof filename, "/proc/%d/exe", pid); - is_elf64 = elf_64_file_p (filename, &machine); - lmo = is_elf64 ? &lmo_64bit_offsets : &lmo_32bit_offsets; - ptr_size = is_elf64 ? 8 : 4; - - while (annex[0] != '\0') - { - const char *sep; - CORE_ADDR *addrp; - int name_len; - - sep = strchr (annex, '='); - if (sep == NULL) - break; - - name_len = sep - annex; - if (name_len == 5 && startswith (annex, "start")) - addrp = &lm_addr; - else if (name_len == 4 && startswith (annex, "prev")) - addrp = &lm_prev; - else - { - annex = strchr (sep, ';'); - if (annex == NULL) - break; - annex++; - continue; - } - - annex = decode_address_to_semicolon (addrp, sep + 1); - } - - if (lm_addr == 0) - { - int r_version = 0; - - if (priv->r_debug == 0) - priv->r_debug = get_r_debug (pid, is_elf64); - - /* We failed to find DT_DEBUG. Such situation will not change - for this inferior - do not retry it. Report it to GDB as - E01, see for the reasons at the GDB solib-svr4.c side. */ - if (priv->r_debug == (CORE_ADDR) -1) - return -1; - - if (priv->r_debug != 0) - { - if (linux_read_memory (priv->r_debug + lmo->r_version_offset, - (unsigned char *) &r_version, - sizeof (r_version)) != 0 - || r_version != 1) - { - warning ("unexpected r_debug version %d", r_version); - } - else if (read_one_ptr (priv->r_debug + lmo->r_map_offset, - &lm_addr, ptr_size) != 0) - { - warning ("unable to read r_map from 0x%lx", - (long) priv->r_debug + lmo->r_map_offset); - } - } - } - - std::string document = "<library-list-svr4 version=\"1.0\""; - - while (lm_addr - && read_one_ptr (lm_addr + lmo->l_name_offset, - &l_name, ptr_size) == 0 - && read_one_ptr (lm_addr + lmo->l_addr_offset, - &l_addr, ptr_size) == 0 - && read_one_ptr (lm_addr + lmo->l_ld_offset, - &l_ld, ptr_size) == 0 - && read_one_ptr (lm_addr + lmo->l_prev_offset, - &l_prev, ptr_size) == 0 - && read_one_ptr (lm_addr + lmo->l_next_offset, - &l_next, ptr_size) == 0) - { - unsigned char libname[PATH_MAX]; - - if (lm_prev != l_prev) - { - warning ("Corrupted shared library list: 0x%lx != 0x%lx", - (long) lm_prev, (long) l_prev); - break; - } - - /* Ignore the first entry even if it has valid name as the first entry - corresponds to the main executable. The first entry should not be - skipped if the dynamic loader was loaded late by a static executable - (see solib-svr4.c parameter ignore_first). But in such case the main - executable does not have PT_DYNAMIC present and this function already - exited above due to failed get_r_debug. */ - if (lm_prev == 0) - string_appendf (document, " main-lm=\"0x%lx\"", (unsigned long) lm_addr); - else - { - /* Not checking for error because reading may stop before - we've got PATH_MAX worth of characters. */ - libname[0] = '\0'; - linux_read_memory (l_name, libname, sizeof (libname) - 1); - libname[sizeof (libname) - 1] = '\0'; - if (libname[0] != '\0') - { - if (!header_done) - { - /* Terminate `<library-list-svr4'. */ - document += '>'; - header_done = 1; - } - - string_appendf (document, "<library name=\""); - xml_escape_text_append (&document, (char *) libname); - string_appendf (document, "\" lm=\"0x%lx\" " - "l_addr=\"0x%lx\" l_ld=\"0x%lx\"/>", - (unsigned long) lm_addr, (unsigned long) l_addr, - (unsigned long) l_ld); - } - } - - lm_prev = lm_addr; - lm_addr = l_next; - } - - if (!header_done) - { - /* Empty list; terminate `<library-list-svr4'. */ - document += "/>"; - } - else - document += "</library-list-svr4>"; - - int document_len = document.length (); - if (offset < document_len) - document_len -= offset; - else - document_len = 0; - if (len > document_len) - len = document_len; - - memcpy (readbuf, document.data () + offset, len); - - return len; -} - -#ifdef HAVE_LINUX_BTRACE - -/* See to_disable_btrace target method. */ - -static int -linux_low_disable_btrace (struct btrace_target_info *tinfo) -{ - enum btrace_error err; - - err = linux_disable_btrace (tinfo); - return (err == BTRACE_ERR_NONE ? 0 : -1); -} - -/* Encode an Intel Processor Trace configuration. */ - -static void -linux_low_encode_pt_config (struct buffer *buffer, - const struct btrace_data_pt_config *config) -{ - buffer_grow_str (buffer, "<pt-config>\n"); - - switch (config->cpu.vendor) - { - case CV_INTEL: - buffer_xml_printf (buffer, "<cpu vendor=\"GenuineIntel\" family=\"%u\" " - "model=\"%u\" stepping=\"%u\"/>\n", - config->cpu.family, config->cpu.model, - config->cpu.stepping); - break; - - default: - break; - } - - buffer_grow_str (buffer, "</pt-config>\n"); -} - -/* Encode a raw buffer. */ - -static void -linux_low_encode_raw (struct buffer *buffer, const gdb_byte *data, - unsigned int size) -{ - if (size == 0) - return; - - /* We use hex encoding - see gdbsupport/rsp-low.h. */ - buffer_grow_str (buffer, "<raw>\n"); - - while (size-- > 0) - { - char elem[2]; - - elem[0] = tohex ((*data >> 4) & 0xf); - elem[1] = tohex (*data++ & 0xf); - - buffer_grow (buffer, elem, 2); - } - - buffer_grow_str (buffer, "</raw>\n"); -} - -/* See to_read_btrace target method. */ - -static int -linux_low_read_btrace (struct btrace_target_info *tinfo, struct buffer *buffer, - enum btrace_read_type type) -{ - struct btrace_data btrace; - enum btrace_error err; - - err = linux_read_btrace (&btrace, tinfo, type); - if (err != BTRACE_ERR_NONE) - { - if (err == BTRACE_ERR_OVERFLOW) - buffer_grow_str0 (buffer, "E.Overflow."); - else - buffer_grow_str0 (buffer, "E.Generic Error."); - - return -1; - } - - switch (btrace.format) - { - case BTRACE_FORMAT_NONE: - buffer_grow_str0 (buffer, "E.No Trace."); - return -1; - - case BTRACE_FORMAT_BTS: - buffer_grow_str (buffer, "<!DOCTYPE btrace SYSTEM \"btrace.dtd\">\n"); - buffer_grow_str (buffer, "<btrace version=\"1.0\">\n"); - - for (const btrace_block &block : *btrace.variant.bts.blocks) - buffer_xml_printf (buffer, "<block begin=\"0x%s\" end=\"0x%s\"/>\n", - paddress (block.begin), paddress (block.end)); - - buffer_grow_str0 (buffer, "</btrace>\n"); - break; - - case BTRACE_FORMAT_PT: - buffer_grow_str (buffer, "<!DOCTYPE btrace SYSTEM \"btrace.dtd\">\n"); - buffer_grow_str (buffer, "<btrace version=\"1.0\">\n"); - buffer_grow_str (buffer, "<pt>\n"); - - linux_low_encode_pt_config (buffer, &btrace.variant.pt.config); - - linux_low_encode_raw (buffer, btrace.variant.pt.data, - btrace.variant.pt.size); - - buffer_grow_str (buffer, "</pt>\n"); - buffer_grow_str0 (buffer, "</btrace>\n"); - break; - - default: - buffer_grow_str0 (buffer, "E.Unsupported Trace Format."); - return -1; - } - - return 0; -} - -/* See to_btrace_conf target method. */ - -static int -linux_low_btrace_conf (const struct btrace_target_info *tinfo, - struct buffer *buffer) -{ - const struct btrace_config *conf; - - buffer_grow_str (buffer, "<!DOCTYPE btrace-conf SYSTEM \"btrace-conf.dtd\">\n"); - buffer_grow_str (buffer, "<btrace-conf version=\"1.0\">\n"); - - conf = linux_btrace_conf (tinfo); - if (conf != NULL) - { - switch (conf->format) - { - case BTRACE_FORMAT_NONE: - break; - - case BTRACE_FORMAT_BTS: - buffer_xml_printf (buffer, "<bts"); - buffer_xml_printf (buffer, " size=\"0x%x\"", conf->bts.size); - buffer_xml_printf (buffer, " />\n"); - break; - - case BTRACE_FORMAT_PT: - buffer_xml_printf (buffer, "<pt"); - buffer_xml_printf (buffer, " size=\"0x%x\"", conf->pt.size); - buffer_xml_printf (buffer, "/>\n"); - break; - } - } - - buffer_grow_str0 (buffer, "</btrace-conf>\n"); - return 0; -} -#endif /* HAVE_LINUX_BTRACE */ - -/* See nat/linux-nat.h. */ - -ptid_t -current_lwp_ptid (void) -{ - return ptid_of (current_thread); -} - -/* Implementation of the target_ops method "breakpoint_kind_from_pc". */ - -static int -linux_breakpoint_kind_from_pc (CORE_ADDR *pcptr) -{ - if (the_low_target.breakpoint_kind_from_pc != NULL) - return (*the_low_target.breakpoint_kind_from_pc) (pcptr); - else - return default_breakpoint_kind_from_pc (pcptr); -} - -/* Implementation of the target_ops method "sw_breakpoint_from_kind". */ - -static const gdb_byte * -linux_sw_breakpoint_from_kind (int kind, int *size) -{ - gdb_assert (the_low_target.sw_breakpoint_from_kind != NULL); - - return (*the_low_target.sw_breakpoint_from_kind) (kind, size); -} - -/* Implementation of the target_ops method - "breakpoint_kind_from_current_state". */ - -static int -linux_breakpoint_kind_from_current_state (CORE_ADDR *pcptr) -{ - if (the_low_target.breakpoint_kind_from_current_state != NULL) - return (*the_low_target.breakpoint_kind_from_current_state) (pcptr); - else - return linux_breakpoint_kind_from_pc (pcptr); -} - -/* Default implementation of linux_target_ops method "set_pc" for - 32-bit pc register which is literally named "pc". */ - -void -linux_set_pc_32bit (struct regcache *regcache, CORE_ADDR pc) -{ - uint32_t newpc = pc; - - supply_register_by_name (regcache, "pc", &newpc); -} - -/* Default implementation of linux_target_ops method "get_pc" for - 32-bit pc register which is literally named "pc". */ - -CORE_ADDR -linux_get_pc_32bit (struct regcache *regcache) -{ - uint32_t pc; - - collect_register_by_name (regcache, "pc", &pc); - if (debug_threads) - debug_printf ("stop pc is 0x%" PRIx32 "\n", pc); - return pc; -} - -/* Default implementation of linux_target_ops method "set_pc" for - 64-bit pc register which is literally named "pc". */ - -void -linux_set_pc_64bit (struct regcache *regcache, CORE_ADDR pc) -{ - uint64_t newpc = pc; - - supply_register_by_name (regcache, "pc", &newpc); -} - -/* Default implementation of linux_target_ops method "get_pc" for - 64-bit pc register which is literally named "pc". */ - -CORE_ADDR -linux_get_pc_64bit (struct regcache *regcache) -{ - uint64_t pc; - - collect_register_by_name (regcache, "pc", &pc); - if (debug_threads) - debug_printf ("stop pc is 0x%" PRIx64 "\n", pc); - return pc; -} - -/* See linux-low.h. */ - -int -linux_get_auxv (int wordsize, CORE_ADDR match, CORE_ADDR *valp) -{ - gdb_byte *data = (gdb_byte *) alloca (2 * wordsize); - int offset = 0; - - gdb_assert (wordsize == 4 || wordsize == 8); - - while ((*the_target->read_auxv) (offset, data, 2 * wordsize) == 2 * wordsize) - { - if (wordsize == 4) - { - uint32_t *data_p = (uint32_t *) data; - if (data_p[0] == match) - { - *valp = data_p[1]; - return 1; - } - } - else - { - uint64_t *data_p = (uint64_t *) data; - if (data_p[0] == match) - { - *valp = data_p[1]; - return 1; - } - } - - offset += 2 * wordsize; - } - - return 0; -} - -/* See linux-low.h. */ - -CORE_ADDR -linux_get_hwcap (int wordsize) -{ - CORE_ADDR hwcap = 0; - linux_get_auxv (wordsize, AT_HWCAP, &hwcap); - return hwcap; -} - -/* See linux-low.h. */ - -CORE_ADDR -linux_get_hwcap2 (int wordsize) -{ - CORE_ADDR hwcap2 = 0; - linux_get_auxv (wordsize, AT_HWCAP2, &hwcap2); - return hwcap2; -} - -static process_stratum_target linux_target_ops = { - linux_create_inferior, - linux_post_create_inferior, - linux_attach, - linux_kill, - linux_detach, - linux_mourn, - linux_join, - linux_thread_alive, - linux_resume, - linux_wait, - linux_fetch_registers, - linux_store_registers, - linux_prepare_to_access_memory, - linux_done_accessing_memory, - linux_read_memory, - linux_write_memory, - linux_look_up_symbols, - linux_request_interrupt, - linux_read_auxv, - linux_supports_z_point_type, - linux_insert_point, - linux_remove_point, - linux_stopped_by_sw_breakpoint, - linux_supports_stopped_by_sw_breakpoint, - linux_stopped_by_hw_breakpoint, - linux_supports_stopped_by_hw_breakpoint, - linux_supports_hardware_single_step, - linux_stopped_by_watchpoint, - linux_stopped_data_address, -#if defined(__UCLIBC__) && defined(HAS_NOMMU) \ - && defined(PT_TEXT_ADDR) && defined(PT_DATA_ADDR) \ - && defined(PT_TEXT_END_ADDR) - linux_read_offsets, -#else - NULL, -#endif -#ifdef USE_THREAD_DB - thread_db_get_tls_address, -#else - NULL, -#endif - hostio_last_error_from_errno, - linux_qxfer_osdata, - linux_xfer_siginfo, - linux_supports_non_stop, - linux_async, - linux_start_non_stop, - linux_supports_multi_process, - linux_supports_fork_events, - linux_supports_vfork_events, - linux_supports_exec_events, - linux_handle_new_gdb_connection, -#ifdef USE_THREAD_DB - thread_db_handle_monitor_command, -#else - NULL, -#endif - linux_common_core_of_thread, - linux_read_loadmap, - linux_process_qsupported, - linux_supports_tracepoints, - linux_read_pc, - linux_write_pc, - linux_thread_stopped, - NULL, - linux_pause_all, - linux_unpause_all, - linux_stabilize_threads, - linux_install_fast_tracepoint_jump_pad, - linux_emit_ops, - linux_supports_disable_randomization, - linux_get_min_fast_tracepoint_insn_len, - linux_qxfer_libraries_svr4, - linux_supports_agent, -#ifdef HAVE_LINUX_BTRACE - linux_enable_btrace, - linux_low_disable_btrace, - linux_low_read_btrace, - linux_low_btrace_conf, -#else - NULL, - NULL, - NULL, - NULL, -#endif - linux_supports_range_stepping, - linux_proc_pid_to_exec_file, - linux_mntns_open_cloexec, - linux_mntns_unlink, - linux_mntns_readlink, - linux_breakpoint_kind_from_pc, - linux_sw_breakpoint_from_kind, - linux_proc_tid_get_name, - linux_breakpoint_kind_from_current_state, - linux_supports_software_single_step, - linux_supports_catch_syscall, - linux_get_ipa_tdesc_idx, -#if USE_THREAD_DB - thread_db_thread_handle, -#else - NULL, -#endif -}; - -#ifdef HAVE_LINUX_REGSETS -void -initialize_regsets_info (struct regsets_info *info) -{ - for (info->num_regsets = 0; - info->regsets[info->num_regsets].size >= 0; - info->num_regsets++) - ; -} -#endif - -void -initialize_low (void) -{ - struct sigaction sigchld_action; - - memset (&sigchld_action, 0, sizeof (sigchld_action)); - set_target_ops (&linux_target_ops); - - linux_ptrace_init_warnings (); - linux_proc_init_warnings (); - - sigchld_action.sa_handler = sigchld_handler; - sigemptyset (&sigchld_action.sa_mask); - sigchld_action.sa_flags = SA_RESTART; - sigaction (SIGCHLD, &sigchld_action, NULL); - - initialize_low_arch (); - - linux_check_ptrace_features (); -} |