diff options
Diffstat (limited to 'gdbserver/netbsd-low.cc')
| -rw-r--r-- | gdbserver/netbsd-low.cc | 1327 |
1 files changed, 1327 insertions, 0 deletions
diff --git a/gdbserver/netbsd-low.cc b/gdbserver/netbsd-low.cc new file mode 100644 index 0000000..8b13b67 --- /dev/null +++ b/gdbserver/netbsd-low.cc @@ -0,0 +1,1327 @@ +/* Copyright (C) 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 "target.h" +#include "netbsd-low.h" +#include "nat/netbsd-nat.h" + +#include <sys/param.h> +#include <sys/types.h> + +#include <sys/ptrace.h> +#include <sys/sysctl.h> + +#include <limits.h> +#include <unistd.h> +#include <signal.h> + +#include <elf.h> + +#include <type_traits> + +#include "gdbsupport/eintr.h" +#include "gdbsupport/gdb_wait.h" +#include "gdbsupport/filestuff.h" +#include "gdbsupport/common-inferior.h" +#include "nat/fork-inferior.h" +#include "hostio.h" + +int using_threads = 1; + +const struct target_desc *netbsd_tdesc; + +/* Call add_process with the given parameters, and initialize + the process' private data. */ + +static void +netbsd_add_process (int pid, int attached) +{ + struct process_info *proc = add_process (pid, attached); + proc->tdesc = netbsd_tdesc; + proc->priv = nullptr; +} + +/* Callback used by fork_inferior to start tracing the inferior. */ + +static void +netbsd_ptrace_fun () +{ + /* Switch child to its own process group so that signals won't + directly affect GDBserver. */ + if (setpgid (0, 0) < 0) + trace_start_error_with_name (("setpgid")); + + if (ptrace (PT_TRACE_ME, 0, nullptr, 0) < 0) + trace_start_error_with_name (("ptrace")); + + /* 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. */ + } + } +} + +/* Implement the create_inferior method of the target_ops vector. */ + +int +netbsd_process_target::create_inferior (const char *program, + const std::vector<char *> &program_args) +{ + std::string str_program_args = construct_inferior_arguments (program_args); + + pid_t pid = fork_inferior (program, str_program_args.c_str (), + get_environ ()->envp (), netbsd_ptrace_fun, + nullptr, nullptr, nullptr, nullptr); + + netbsd_add_process (pid, 0); + + post_fork_inferior (pid, program); + + return pid; +} + +/* Implement the post_create_inferior target_ops method. */ + +void +netbsd_process_target::post_create_inferior () +{ + pid_t pid = current_process ()->pid; + netbsd_nat::enable_proc_events (pid); +} + +/* Implement the attach target_ops method. */ + +int +netbsd_process_target::attach (unsigned long pid) +{ + /* Unimplemented. */ + return -1; +} + +/* Returns true if GDB is interested in any child syscalls. */ + +static bool +gdb_catching_syscalls_p (pid_t pid) +{ + struct process_info *proc = find_process_pid (pid); + return !proc->syscalls_to_catch.empty (); +} + +/* Implement the resume target_ops method. */ + +void +netbsd_process_target::resume (struct thread_resume *resume_info, size_t n) +{ + ptid_t resume_ptid = resume_info[0].thread; + const int signal = resume_info[0].sig; + const bool step = resume_info[0].kind == resume_step; + + if (resume_ptid == minus_one_ptid) + resume_ptid = ptid_of (current_thread); + + const pid_t pid = resume_ptid.pid (); + const lwpid_t lwp = resume_ptid.lwp (); + regcache_invalidate_pid (pid); + + auto fn + = [&] (ptid_t ptid) + { + if (step) + { + if (ptid.lwp () == lwp || n != 1) + { + if (ptrace (PT_SETSTEP, pid, NULL, ptid.lwp ()) == -1) + perror_with_name (("ptrace")); + if (ptrace (PT_RESUME, pid, NULL, ptid.lwp ()) == -1) + perror_with_name (("ptrace")); + } + else + { + if (ptrace (PT_CLEARSTEP, pid, NULL, ptid.lwp ()) == -1) + perror_with_name (("ptrace")); + if (ptrace (PT_SUSPEND, pid, NULL, ptid.lwp ()) == -1) + perror_with_name (("ptrace")); + } + } + else + { + if (ptrace (PT_CLEARSTEP, pid, NULL, ptid.lwp ()) == -1) + perror_with_name (("ptrace")); + if (ptrace (PT_RESUME, pid, NULL, ptid.lwp ()) == -1) + perror_with_name (("ptrace")); + } + }; + + netbsd_nat::for_each_thread (pid, fn); + + int request = gdb_catching_syscalls_p (pid) ? PT_CONTINUE : PT_SYSCALL; + + errno = 0; + ptrace (request, pid, (void *)1, signal); + if (errno) + perror_with_name (("ptrace")); +} + +/* Returns true if GDB is interested in the reported SYSNO syscall. */ + +static bool +netbsd_catch_this_syscall (int sysno) +{ + struct process_info *proc = current_process (); + + if (proc->syscalls_to_catch.empty ()) + return false; + + if (proc->syscalls_to_catch[0] == ANY_SYSCALL) + return true; + + for (int iter : proc->syscalls_to_catch) + if (iter == sysno) + return true; + + return false; +} + +/* Helper function for child_wait and the derivatives of child_wait. + HOSTSTATUS is the waitstatus from wait() or the equivalent; store our + translation of that in OURSTATUS. */ + +static void +netbsd_store_waitstatus (struct target_waitstatus *ourstatus, int hoststatus) +{ + if (WIFEXITED (hoststatus)) + { + ourstatus->kind = TARGET_WAITKIND_EXITED; + ourstatus->value.integer = WEXITSTATUS (hoststatus); + } + else if (!WIFSTOPPED (hoststatus)) + { + ourstatus->kind = TARGET_WAITKIND_SIGNALLED; + ourstatus->value.sig = gdb_signal_from_host (WTERMSIG (hoststatus)); + } + else + { + ourstatus->kind = TARGET_WAITKIND_STOPPED; + ourstatus->value.sig = gdb_signal_from_host (WSTOPSIG (hoststatus)); + } +} + +/* Implement a safe wrapper around waitpid(). */ + +static pid_t +netbsd_waitpid (ptid_t ptid, struct target_waitstatus *ourstatus, int options) +{ + int status; + + pid_t pid + = gdb::handle_eintr<int> (-1, ::waitpid, ptid.pid (), &status, options); + + if (pid == -1) + perror_with_name (_("Child process unexpectedly missing")); + + netbsd_store_waitstatus (ourstatus, status); + return pid; +} + + +/* Implement the wait target_ops method. + + Wait for the child specified by PTID to do something. Return the + process ID of the child, or MINUS_ONE_PTID in case of error; store + the status in *OURSTATUS. */ + +static ptid_t +netbsd_wait (ptid_t ptid, struct target_waitstatus *ourstatus, + int target_options) +{ + pid_t pid = netbsd_waitpid (ptid, ourstatus, target_options); + ptid_t wptid = ptid_t (pid); + + if (pid == 0) + { + gdb_assert (target_options & TARGET_WNOHANG); + ourstatus->kind = TARGET_WAITKIND_IGNORE; + return null_ptid; + } + + gdb_assert (pid != -1); + + /* If the child stopped, keep investigating its status. */ + if (ourstatus->kind != TARGET_WAITKIND_STOPPED) + return wptid; + + /* Extract the event and thread that received a signal. */ + ptrace_siginfo_t psi; + if (ptrace (PT_GET_SIGINFO, pid, &psi, sizeof (psi)) == -1) + perror_with_name (("ptrace")); + + /* Pick child's siginfo_t. */ + siginfo_t *si = &psi.psi_siginfo; + + lwpid_t lwp = psi.psi_lwpid; + + int signo = si->si_signo; + const int code = si->si_code; + + /* Construct PTID with a specified thread that received the event. + If a signal was targeted to the whole process, lwp is 0. */ + wptid = ptid_t (pid, lwp, 0); + + /* Bail out on non-debugger oriented signals. */ + if (signo != SIGTRAP) + return wptid; + + /* Stop examining non-debugger oriented SIGTRAP codes. */ + if (code <= SI_USER || code == SI_NOINFO) + return wptid; + + /* Process state for threading events. */ + ptrace_state_t pst = {}; + if (code == TRAP_LWP) + if (ptrace (PT_GET_PROCESS_STATE, pid, &pst, sizeof (pst)) == -1) + perror_with_name (("ptrace")); + + if (code == TRAP_LWP && pst.pe_report_event == PTRACE_LWP_EXIT) + { + /* If GDB attaches to a multi-threaded process, exiting + threads might be skipped during post_attach that + have not yet reported their PTRACE_LWP_EXIT event. + Ignore exited events for an unknown LWP. */ + thread_info *thr = find_thread_ptid (wptid); + if (thr == nullptr) + ourstatus->kind = TARGET_WAITKIND_SPURIOUS; + else + { + ourstatus->kind = TARGET_WAITKIND_THREAD_EXITED; + /* NetBSD does not store an LWP exit status. */ + ourstatus->value.integer = 0; + + remove_thread (thr); + } + return wptid; + } + + if (find_thread_ptid (ptid_t (pid))) + current_thread = find_thread_ptid (wptid); + + if (code == TRAP_LWP && pst.pe_report_event == PTRACE_LWP_CREATE) + { + /* If GDB attaches to a multi-threaded process, newborn + threads might be added by nbsd_add_threads that have + not yet reported their PTRACE_LWP_CREATE event. Ignore + born events for an already-known LWP. */ + if (find_thread_ptid (wptid)) + ourstatus->kind = TARGET_WAITKIND_SPURIOUS; + else + { + add_thread (wptid, NULL); + ourstatus->kind = TARGET_WAITKIND_THREAD_CREATED; + } + return wptid; + } + + if (code == TRAP_EXEC) + { + ourstatus->kind = TARGET_WAITKIND_EXECD; + ourstatus->value.execd_pathname + = xstrdup (netbsd_nat::pid_to_exec_file (pid)); + return wptid; + } + + if (code == TRAP_TRACE) + return wptid; + + if (code == TRAP_SCE || code == TRAP_SCX) + { + int sysnum = si->si_sysnum; + + if (!netbsd_catch_this_syscall(sysnum)) + { + /* If the core isn't interested in this event, ignore it. */ + ourstatus->kind = TARGET_WAITKIND_SPURIOUS; + return wptid; + } + + ourstatus->kind + = ((code == TRAP_SCE) ? TARGET_WAITKIND_SYSCALL_ENTRY : + TARGET_WAITKIND_SYSCALL_RETURN); + ourstatus->value.syscall_number = sysnum; + return wptid; + } + + if (code == TRAP_BRKPT) + { +#ifdef PTRACE_BREAKPOINT_ADJ + CORE_ADDR pc; + struct reg r; + ptrace (PT_GETREGS, pid, &r, psi.psi_lwpid); + pc = PTRACE_REG_PC (&r); + PTRACE_REG_SET_PC (&r, pc - PTRACE_BREAKPOINT_ADJ); + ptrace (PT_SETREGS, pid, &r, psi.psi_lwpid); +#endif + return wptid; + } + + /* Unclassified SIGTRAP event. */ + ourstatus->kind = TARGET_WAITKIND_SPURIOUS; + return wptid; +} + +/* Implement the wait target_ops method. */ + +ptid_t +netbsd_process_target::wait (ptid_t ptid, struct target_waitstatus *ourstatus, + int target_options) +{ + while (true) + { + ptid_t wptid = netbsd_wait (ptid, ourstatus, target_options); + + /* Register thread in the gdbcore if a thread was not reported earlier. + This is required after ::create_inferior, when the gdbcore does not + know about the first internal thread. + This may also happen on attach, when an event is registered on a thread + that was not fully initialized during the attach stage. */ + if (wptid.lwp () != 0 && !find_thread_ptid (wptid) + && ourstatus->kind != TARGET_WAITKIND_THREAD_EXITED) + add_thread (wptid, nullptr); + + switch (ourstatus->kind) + { + case TARGET_WAITKIND_EXITED: + case TARGET_WAITKIND_STOPPED: + case TARGET_WAITKIND_SIGNALLED: + case TARGET_WAITKIND_FORKED: + case TARGET_WAITKIND_VFORKED: + case TARGET_WAITKIND_EXECD: + case TARGET_WAITKIND_VFORK_DONE: + case TARGET_WAITKIND_SYSCALL_ENTRY: + case TARGET_WAITKIND_SYSCALL_RETURN: + /* Pass the result to the generic code. */ + return wptid; + case TARGET_WAITKIND_THREAD_CREATED: + case TARGET_WAITKIND_THREAD_EXITED: + /* The core needlessly stops on these events. */ + /* FALLTHROUGH */ + case TARGET_WAITKIND_SPURIOUS: + /* Spurious events are unhandled by the gdbserver core. */ + if (ptrace (PT_CONTINUE, current_process ()->pid, (void *) 1, 0) + == -1) + perror_with_name (("ptrace")); + break; + default: + error (("Unknown stopped status")); + } + } +} + +/* Implement the kill target_ops method. */ + +int +netbsd_process_target::kill (process_info *process) +{ + pid_t pid = process->pid; + if (ptrace (PT_KILL, pid, nullptr, 0) == -1) + return -1; + + int status; + if (gdb::handle_eintr<int> (-1, ::waitpid, pid, &status, 0) == -1) + return -1; + mourn (process); + return 0; +} + +/* Implement the detach target_ops method. */ + +int +netbsd_process_target::detach (process_info *process) +{ + pid_t pid = process->pid; + + ptrace (PT_DETACH, pid, (void *) 1, 0); + mourn (process); + return 0; +} + +/* Implement the mourn target_ops method. */ + +void +netbsd_process_target::mourn (struct process_info *proc) +{ + for_each_thread (proc->pid, remove_thread); + + remove_process (proc); +} + +/* Implement the join target_ops method. */ + +void +netbsd_process_target::join (int pid) +{ + /* The PT_DETACH is sufficient to detach from the process. + So no need to do anything extra. */ +} + +/* Implement the thread_alive target_ops method. */ + +bool +netbsd_process_target::thread_alive (ptid_t ptid) +{ + return netbsd_nat::thread_alive (ptid); +} + +/* Implement the fetch_registers target_ops method. */ + +void +netbsd_process_target::fetch_registers (struct regcache *regcache, int regno) +{ + struct netbsd_regset_info *regset = netbsd_target_regsets; + ptid_t inferior_ptid = ptid_of (current_thread); + + while (regset->size >= 0) + { + std::vector<char> buf; + buf.resize (regset->size); + int res = ptrace (regset->get_request, inferior_ptid.pid (), buf.data (), + inferior_ptid.lwp ()); + if (res == -1) + perror_with_name (("ptrace")); + regset->store_function (regcache, buf.data ()); + regset++; + } +} + +/* Implement the store_registers target_ops method. */ + +void +netbsd_process_target::store_registers (struct regcache *regcache, int regno) +{ + struct netbsd_regset_info *regset = netbsd_target_regsets; + ptid_t inferior_ptid = ptid_of (current_thread); + + while (regset->size >= 0) + { + std::vector<char> buf; + buf.resize (regset->size); + int res = ptrace (regset->get_request, inferior_ptid.pid (), buf.data (), + inferior_ptid.lwp ()); + if (res == -1) + perror_with_name (("ptrace")); + + /* Then overlay our cached registers on that. */ + regset->fill_function (regcache, buf.data ()); + /* Only now do we write the register set. */ + res = ptrace (regset->set_request, inferior_ptid.pid (), buf. data (), + inferior_ptid.lwp ()); + if (res == -1) + perror_with_name (("ptrace")); + regset++; + } +} + +/* Implement the read_memory target_ops method. */ + +int +netbsd_process_target::read_memory (CORE_ADDR memaddr, unsigned char *myaddr, + int size) +{ + struct ptrace_io_desc io; + io.piod_op = PIOD_READ_D; + io.piod_len = size; + + pid_t pid = current_process ()->pid; + + int bytes_read = 0; + + if (size == 0) + { + /* Zero length write always succeeds. */ + return 0; + } + do + { + io.piod_offs = (void *)(memaddr + bytes_read); + io.piod_addr = myaddr + bytes_read; + + int rv = ptrace (PT_IO, pid, &io, 0); + if (rv == -1) + return errno; + if (io.piod_len == 0) + return 0; + + bytes_read += io.piod_len; + io.piod_len = size - bytes_read; + } + while (bytes_read < size); + + return 0; +} + +/* Implement the write_memory target_ops method. */ + +int +netbsd_process_target::write_memory (CORE_ADDR memaddr, + const unsigned char *myaddr, int size) +{ + struct ptrace_io_desc io; + io.piod_op = PIOD_WRITE_D; + io.piod_len = size; + + pid_t pid = current_process ()->pid; + + int bytes_written = 0; + + if (size == 0) + { + /* Zero length write always succeeds. */ + return 0; + } + + do + { + io.piod_addr = (void *)(myaddr + bytes_written); + io.piod_offs = (void *)(memaddr + bytes_written); + + int rv = ptrace (PT_IO, pid, &io, 0); + if (rv == -1) + return errno; + if (io.piod_len == 0) + return 0; + + bytes_written += io.piod_len; + io.piod_len = size - bytes_written; + } + while (bytes_written < size); + + return 0; +} + +/* Implement the request_interrupt target_ops method. */ + +void +netbsd_process_target::request_interrupt () +{ + ptid_t inferior_ptid = ptid_of (get_first_thread ()); + + ::kill (inferior_ptid.pid(), SIGINT); +} + +/* Read the AUX Vector for the specified PID, wrapping the ptrace(2) call + with the PIOD_READ_AUXV operation and using the PT_IO standard input + and output arguments. */ + +static size_t +netbsd_read_auxv(pid_t pid, void *offs, void *addr, size_t len) +{ + struct ptrace_io_desc pio; + + pio.piod_op = PIOD_READ_AUXV; + pio.piod_offs = offs; + pio.piod_addr = addr; + pio.piod_len = len; + + if (ptrace (PT_IO, pid, &pio, 0) == -1) + perror_with_name (("ptrace")); + + return pio.piod_len; +} + +/* Copy LEN bytes from inferior's auxiliary vector starting at OFFSET + to debugger memory starting at MYADDR. */ + +int +netbsd_process_target::read_auxv (CORE_ADDR offset, + unsigned char *myaddr, unsigned int len) +{ + pid_t pid = pid_of (current_thread); + + return netbsd_read_auxv (pid, (void *) (intptr_t) offset, myaddr, len); +} + +bool +netbsd_process_target::supports_z_point_type (char z_type) +{ + switch (z_type) + { + case Z_PACKET_SW_BP: + return true; + case Z_PACKET_HW_BP: + case Z_PACKET_WRITE_WP: + case Z_PACKET_READ_WP: + case Z_PACKET_ACCESS_WP: + default: + return false; /* Not supported. */ + } +} + +/* Insert {break/watch}point at address ADDR. SIZE is not used. */ + +int +netbsd_process_target::insert_point (enum raw_bkpt_type type, CORE_ADDR addr, + int size, struct raw_breakpoint *bp) +{ + switch (type) + { + case raw_bkpt_type_sw: + return insert_memory_breakpoint (bp); + case raw_bkpt_type_hw: + case raw_bkpt_type_write_wp: + case raw_bkpt_type_read_wp: + case raw_bkpt_type_access_wp: + default: + return 1; /* Not supported. */ + } +} + +/* Remove {break/watch}point at address ADDR. SIZE is not used. */ + +int +netbsd_process_target::remove_point (enum raw_bkpt_type type, CORE_ADDR addr, + int size, struct raw_breakpoint *bp) +{ + switch (type) + { + case raw_bkpt_type_sw: + return remove_memory_breakpoint (bp); + case raw_bkpt_type_hw: + case raw_bkpt_type_write_wp: + case raw_bkpt_type_read_wp: + case raw_bkpt_type_access_wp: + default: + return 1; /* Not supported. */ + } +} + +/* Implement the stopped_by_sw_breakpoint target_ops method. */ + +bool +netbsd_process_target::stopped_by_sw_breakpoint () +{ + ptrace_siginfo_t psi; + pid_t pid = current_process ()->pid; + + if (ptrace (PT_GET_SIGINFO, pid, &psi, sizeof (psi)) == -1) + perror_with_name (("ptrace")); + + return psi.psi_siginfo.si_signo == SIGTRAP && + psi.psi_siginfo.si_code == TRAP_BRKPT; +} + +/* Implement the supports_stopped_by_sw_breakpoint target_ops method. */ + +bool +netbsd_process_target::supports_stopped_by_sw_breakpoint () +{ + return true; +} + +/* Implement the supports_qxfer_siginfo target_ops method. */ + +bool +netbsd_process_target::supports_qxfer_siginfo () +{ + return true; +} + +/* Implement the qxfer_siginfo target_ops method. */ + +int +netbsd_process_target::qxfer_siginfo (const char *annex, unsigned char *readbuf, + unsigned const char *writebuf, + CORE_ADDR offset, int len) +{ + if (current_thread == nullptr) + return -1; + + pid_t pid = current_process ()->pid; + + return netbsd_nat::qxfer_siginfo(pid, annex, readbuf, writebuf, offset, len); +} + +/* Implement the supports_non_stop target_ops method. */ + +bool +netbsd_process_target::supports_non_stop () +{ + return false; +} + +/* Implement the supports_multi_process target_ops method. */ + +bool +netbsd_process_target::supports_multi_process () +{ + return true; +} + +/* Check if fork events are supported. */ + +bool +netbsd_process_target::supports_fork_events () +{ + return false; +} + +/* Check if vfork events are supported. */ + +bool +netbsd_process_target::supports_vfork_events () +{ + return false; +} + +/* Check if exec events are supported. */ + +bool +netbsd_process_target::supports_exec_events () +{ + return true; +} + +/* Implement the supports_disable_randomization target_ops method. */ + +bool +netbsd_process_target::supports_disable_randomization () +{ + return false; +} + +/* Extract &phdr and num_phdr in the inferior. Return 0 on success. */ + +template <typename T> +int get_phdr_phnum_from_proc_auxv (const pid_t pid, + CORE_ADDR *phdr_memaddr, int *num_phdr) +{ + typedef typename std::conditional<sizeof(T) == sizeof(int64_t), + Aux64Info, Aux32Info>::type auxv_type; + const size_t auxv_size = sizeof (auxv_type); + const size_t auxv_buf_size = 128 * sizeof (auxv_type); + + std::vector<char> auxv_buf; + auxv_buf.resize (auxv_buf_size); + + netbsd_read_auxv (pid, nullptr, auxv_buf.data (), auxv_buf_size); + + *phdr_memaddr = 0; + *num_phdr = 0; + + for (char *buf = auxv_buf.data (); + buf < (auxv_buf.data () + auxv_buf_size); + buf += auxv_size) + { + auxv_type *const aux = (auxv_type *) buf; + + switch (aux->a_type) + { + case AT_PHDR: + *phdr_memaddr = aux->a_v; + break; + case AT_PHNUM: + *num_phdr = aux->a_v; + break; + } + + if (*phdr_memaddr != 0 && *num_phdr != 0) + break; + } + + if (*phdr_memaddr == 0 || *num_phdr == 0) + { + warning ("Unexpected missing AT_PHDR and/or AT_PHNUM: " + "phdr_memaddr = %s, phdr_num = %d", + core_addr_to_string (*phdr_memaddr), *num_phdr); + return 2; + } + + return 0; +} + +/* Return &_DYNAMIC (via PT_DYNAMIC) in the inferior, or 0 if not present. */ + +template <typename T> +static CORE_ADDR +get_dynamic (netbsd_process_target *target, const pid_t pid) +{ + typedef typename std::conditional<sizeof(T) == sizeof(int64_t), + Elf64_Phdr, Elf32_Phdr>::type phdr_type; + const int phdr_size = sizeof (phdr_type); + + CORE_ADDR phdr_memaddr; + int num_phdr; + if (get_phdr_phnum_from_proc_auxv<T> (pid, &phdr_memaddr, &num_phdr)) + return 0; + + std::vector<unsigned char> phdr_buf; + phdr_buf.resize (num_phdr * phdr_size); + + if (target->read_memory (phdr_memaddr, phdr_buf.data (), phdr_buf.size ())) + return 0; + + /* Compute relocation: it is expected to be 0 for "regular" executables, + non-zero for PIE ones. */ + CORE_ADDR relocation = -1; + for (int i = 0; relocation == -1 && i < num_phdr; i++) + { + phdr_type *const p = (phdr_type *) (phdr_buf.data() + 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 (int i = 0; i < num_phdr; i++) + { + phdr_type *const p = (phdr_type *) (phdr_buf.data () + 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. */ + +template <typename T> +static CORE_ADDR +get_r_debug (netbsd_process_target *target, const int pid) +{ + typedef typename std::conditional<sizeof(T) == sizeof(int64_t), + Elf64_Dyn, Elf32_Dyn>::type dyn_type; + const int dyn_size = sizeof (dyn_type); + unsigned char buf[sizeof (dyn_type)]; /* The larger of the two. */ + CORE_ADDR map = -1; + + CORE_ADDR dynamic_memaddr = get_dynamic<T> (target, pid); + if (dynamic_memaddr == 0) + return map; + + while (target->read_memory (dynamic_memaddr, buf, dyn_size) == 0) + { + dyn_type *const dyn = (dyn_type *) buf; +#if defined DT_MIPS_RLD_MAP + union + { + T map; + unsigned char buf[sizeof (T)]; + } + rld_map; + + if (dyn->d_tag == DT_MIPS_RLD_MAP) + { + if (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 */ + + 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 (netbsd_process_target *target, CORE_ADDR memaddr, CORE_ADDR *ptr, + int ptr_size) +{ + /* 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; + + int ret = target->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; +} + +/* Construct qXfer:libraries-svr4:read reply. */ + +template <typename T> +int +netbsd_qxfer_libraries_svr4 (netbsd_process_target *target, + const pid_t pid, const char *annex, + unsigned char *readbuf, + unsigned const char *writebuf, + CORE_ADDR offset, int len) +{ + 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; + }; + + 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. */ + }; + + CORE_ADDR lm_addr = 0, lm_prev = 0; + CORE_ADDR l_name, l_addr, l_ld, l_next, l_prev; + int header_done = 0; + + const struct link_map_offsets *lmo + = ((sizeof (T) == sizeof (int64_t)) + ? &lmo_64bit_offsets : &lmo_32bit_offsets); + int ptr_size = sizeof (T); + + while (annex[0] != '\0') + { + const char *sep = strchr (annex, '='); + if (sep == nullptr) + break; + + int name_len = sep - annex; + CORE_ADDR *addrp; + 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 == nullptr) + break; + annex++; + continue; + } + + annex = decode_address_to_semicolon (addrp, sep + 1); + } + + if (lm_addr == 0) + { + CORE_ADDR r_debug = get_r_debug<T> (target, pid); + + /* 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 (r_debug == (CORE_ADDR) -1) + return -1; + + if (r_debug != 0) + { + CORE_ADDR map_offset = r_debug + lmo->r_map_offset; + if (read_one_ptr (target, map_offset, &lm_addr, ptr_size) != 0) + warning ("unable to read r_map from %s", + core_addr_to_string (map_offset)); + } + } + + std::string document = "<library-list-svr4 version=\"1.0\""; + + while (lm_addr + && read_one_ptr (target, lm_addr + lmo->l_name_offset, + &l_name, ptr_size) == 0 + && read_one_ptr (target, lm_addr + lmo->l_addr_offset, + &l_addr, ptr_size) == 0 + && read_one_ptr (target, lm_addr + lmo->l_ld_offset, + &l_ld, ptr_size) == 0 + && read_one_ptr (target, lm_addr + lmo->l_prev_offset, + &l_prev, ptr_size) == 0 + && read_one_ptr (target, lm_addr + lmo->l_next_offset, + &l_next, ptr_size) == 0) + { + 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 + { + unsigned char libname[PATH_MAX]; + + /* Not checking for error because reading may stop before + we've got PATH_MAX worth of characters. */ + libname[0] = '\0'; + target->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; +} + +/* Return true if FILE is a 64-bit ELF file, + false if the file is not a 64-bit ELF file, + and error if the file is not accessible or doesn't exist. */ + +static bool +elf_64_file_p (const char *file) +{ + int fd = gdb::handle_eintr<int> (-1, ::open, file, O_RDONLY); + if (fd < 0) + perror_with_name (("open")); + + Elf64_Ehdr header; + ssize_t ret = gdb::handle_eintr<ssize_t> (-1, ::read, fd, &header, sizeof (header)); + if (ret == -1) + perror_with_name (("read")); + gdb::handle_eintr<int> (-1, ::close, fd); + if (ret != sizeof (header)) + error ("Cannot read ELF file header: %s", file); + + 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) + error ("Unrecognized ELF file header: %s", file); + + return header.e_ident[EI_CLASS] == ELFCLASS64; +} + +/* Construct qXfer:libraries-svr4:read reply. */ + +int +netbsd_process_target::qxfer_libraries_svr4 (const char *annex, + unsigned char *readbuf, + unsigned const char *writebuf, + CORE_ADDR offset, int len) +{ + if (writebuf != nullptr) + return -2; + if (readbuf == nullptr) + return -1; + + struct process_info *proc = current_process (); + pid_t pid = proc->pid; + bool is_elf64 = elf_64_file_p (netbsd_nat::pid_to_exec_file (pid)); + + if (is_elf64) + return netbsd_qxfer_libraries_svr4<int64_t> (this, pid, annex, readbuf, + writebuf, offset, len); + else + return netbsd_qxfer_libraries_svr4<int32_t> (this, pid, annex, readbuf, + writebuf, offset, len); +} + +/* Implement the supports_qxfer_libraries_svr4 target_ops method. */ + +bool +netbsd_process_target::supports_qxfer_libraries_svr4 () +{ + return true; +} + +/* Return the name of a file that can be opened to get the symbols for + the child process identified by PID. */ + +char * +netbsd_process_target::pid_to_exec_file (pid_t pid) +{ + return const_cast<char *> (netbsd_nat::pid_to_exec_file (pid)); +} + +/* Implementation of the target_ops method "supports_pid_to_exec_file". */ + +bool +netbsd_process_target::supports_pid_to_exec_file () +{ + return true; +} + +/* Implementation of the target_ops method "supports_hardware_single_step". */ +bool +netbsd_process_target::supports_hardware_single_step () +{ + return true; +} + +/* Implementation of the target_ops method "sw_breakpoint_from_kind". */ + +const gdb_byte * +netbsd_process_target::sw_breakpoint_from_kind (int kind, int *size) +{ + static gdb_byte brkpt[PTRACE_BREAKPOINT_SIZE] = {*PTRACE_BREAKPOINT}; + + *size = PTRACE_BREAKPOINT_SIZE; + + return brkpt; +} + +/* Implement the thread_name target_ops method. */ + +const char * +netbsd_process_target::thread_name (ptid_t ptid) +{ + return netbsd_nat::thread_name (ptid); +} + +/* Implement the supports_catch_syscall target_ops method. */ + +bool +netbsd_process_target::supports_catch_syscall () +{ + return true; +} + +/* Implement the supports_read_auxv target_ops method. */ + +bool +netbsd_process_target::supports_read_auxv () +{ + return true; +} + +/* The NetBSD target ops object. */ + +static netbsd_process_target the_netbsd_target; + +void +initialize_low () +{ + set_target_ops (&the_netbsd_target); + the_low_target.arch_setup (); +} |