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authorDaniel Jacobowitz <drow@false.org>2002-06-11 17:32:40 +0000
committerDaniel Jacobowitz <drow@false.org>2002-06-11 17:32:40 +0000
commit0d62e5e8077eecf77e9b7b5dc0d2689d051a3ab3 (patch)
treeee5fbf8ea12374edac6fb09f1ba62f9d0daefdc6 /gdb/gdbserver/linux-low.c
parentcef717dccf6cfbbd89cd37a79945926aad945261 (diff)
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2002-06-11 Daniel Jacobowitz <drow@mvista.com>
* gdbserver/thread-db.c: New file. * gdbserver/proc-service.c: New file. * gdbserver/acinclude.m4: New file. * gdbserver/Makefile.in: Add GDBSERVER_LIBS, gdb_proc_service_h, proc-service.o, and thread-db.o. (linux-low.o): Add USE_THREAD_DB. * gdbserver/acconfig.h: Add HAVE_PRGREGSET_T, HAVE_PRFPREGSET_T, HAVE_LWPID_T, HAVE_PSADDR_T, and PRFPREGSET_T_BROKEN. * gdbserver/aclocal.m4: Regenerated. * gdbserver/config.in: Regenerated. * gdbserver/configure: Regenerated. * gdbserver/configure.in: Check for proc_service.h, sys/procfs.h, thread_db.h, and linux/elf.h headrs. Check for lwpid_t, psaddr_t, prgregset_t, prfpregset_t, and PRFPREGSET_T_BROKEN. Introduce srv_thread_depfiles and USE_THREAD_DB. Check for -lthread_db and thread support. * gdbserver/configure.srv: Enable thread_db support for ARM, i386, MIPS, PowerPC, and SuperH. * gdbserver/i387-fp.c: Constify arguments. * gdbserver/i387-fp.h: Likewise. * gdbserver/inferiors.c: (struct thread_info): Renamed from `struct inferior_info'. Remove PID member. Use generic inferior list header. All uses updated. (inferiors, signal_pid): Removed. (all_threads): New variable. (get_thread): Define. (add_inferior_to_list): New function. (for_each_inferior): New function. (change_inferior_id): New function. (add_inferior): Removed. (remove_inferior): New function. (add_thread): New function. (free_one_thread): New function. (remove_thread): New function. (clear_inferiors): Use for_each_inferior and free_one_thread. (find_inferior): New function. (find_inferior_id): New function. (inferior_target_data): Update argument type. (set_inferior_target_data): Likewise. (inferior_regcache_data): Likewise. (set_inferior_regcache_data): Likewise. * gdbserver/linux-low.c (linux_bp_reinsert): Remove. (all_processes, stopping_threads, using_thrads) (struct pending_signals, debug_threads, pid_of): New. (inferior_pid): Replace with macro. (struct inferior_linux_data): Remove. (get_stop_pc, add_process): New functions. (linux_create_inferior): Restore SIGRTMIN+1 before calling exec. Use add_process and add_thread. (linux_attach_lwp): New function, based on old linux_attach. Use add_process and add_thread. Set stop_expected for new threads. (linux_attach): New function. (linux_kill_one_process): New function. (linux_kill): Kill all LWPs. (linux_thread_alive): Use find_inferior_id. (check_removed_breakpoints, status_pending_p): New functions. (linux_wait_for_process): Renamed from linux_wait_for_one_inferior. Update. Use WNOHANG. Wait for cloned processes also. Update process struct for the found process. (linux_wait_for_event): New function. (linux_wait): Use it. Support LWPs. (send_sigstop, wait_for_sigstop, stop_all_processes) (linux_resume_one_process, linux_continue_one_process): New functions. (linux_resume): Support LWPs. (REGISTER_RAW_SIZE): Remove. (fetch_register): Use register_size instead. Call supply_register. (usr_store_inferior_registers): Likewise. Call collect_register. Fix recursive case. (regsets_fetch_inferior_registers): Improve error message. (regsets_store_inferior_registers): Add debugging. (linux_look_up_symbols): Call thread_db_init if USE_THREAD_DB. (unstopped_p, linux_signal_pid): New functions. (linux_target_ops): Add linux_signal_pid. (linux_init_signals): New function. (initialize_low): Call it. Initialize using_threads. * gdbserver/regcache.c (inferior_regcache_data): Add valid flag. (get_regcache): Fetch registers lazily. Add fetch argument and update all callers. (regcache_invalidate_one, regcache_invalidate): New functions. (new_register_cache): Renamed from create_register_cache. Return the new regcache. (free_register_cache): Change argument to a void *. (registers_to_string, registers_from_string): Call get_regcache with fetch flag set. (register_data): Make static. Pass fetch flag to get_regcache. (supply_register): Call get_regcache with fetch flag clear. (collect_register): Call get_regcache with fetch flag set. (collect_register_as_string): New function. * gdbserver/regcache.h: Update. * gdbserver/remote-utils.c (putpkt): Flush after debug output and use stderr. Handle input interrupts while waiting for an ACK. (input_interrupt): Use signal_pid method. (getpkt): Flush after debug output and use stderr. (outreg): Use collect_register_as_string. (new_thread_notify, dead_thread_notify): New functions. (prepare_resume_reply): Check using_threads. Set thread_from_wait and general_thread. (look_up_one_symbol): Flush after debug output. * gdbserver/server.c (step_thread, server_waiting): New variables. (start_inferior): Don't use signal_pid. Update call to mywait. (attach_inferior): Update call to mywait. (handle_query): Handle qfThreadInfo and qsThreadInfo. (main): Don't fetch/store registers explicitly. Use set_desired_inferior. Support proposed ``Hs'' packet. Update calls to mywait. * gdbserver/server.h: Update. (struct inferior_list, struct_inferior_list_entry): New. * gdbserver/target.c (set_desired_inferior): New. (write_inferior_memory): Constify. (mywait): New function. * gdbserver/target.h: Update. (struct target_ops): New signal_pid method. (mywait): Removed macro, added prototype. * gdbserver/linux-low.h (regset_func): Removed. (regset_fill_func, regset_store_func): New. (enum regset_type): New. (struct regset_info): Add type field. Use new operation types. (struct linux_target_ops): stop_pc renamed to get_pc. Add decr_pc_after_break and breakpoint_at. (get_process, get_thread_proess, get_process_thread) (strut process_info, all_processes, linux_attach_lwp) (thread_db_init): New. * gdbserver/linux-arm-low.c (arm_get_pc, arm_set_pc, arm_breakpoint, arm_breakpoint_len, arm_breakpoint_at): New. (the_low_target): Add new members. * gdbserver/linux-i386-low.c (i386_store_gregset, i386_store_fpregset) (i386_store_fpxregset): Constify. (target_regsets): Add new kind identifier. (i386_get_pc): Renamed from i386_stop_pc. Simplify. (i386_set_pc): Add debugging. (i386_breakpoint_at): New function. (the_low_target): Add new members. * gdbserver/linux-mips-low.c (mips_get_pc, mips_set_pc) (mips_breakpoint, mips_breakpoint_len, mips_reinsert_addr) (mips_breakpoint_at): New. (the_low_target): Add new members. * gdbserver/linux-ppc-low.c (ppc_get_pc, ppc_set_pc) (ppc_breakpoint, ppc_breakpoint_len, ppc_breakpoint_at): New. (the_low_target): Add new members. * gdbserver/linux-sh-low.c (sh_get_pc, sh_set_pc) (sh_breakpoint, sh_breakpoint_len, sh_breakpoint_at): New. (the_low_target): Add new members. * gdbserver/linux-x86-64-low.c (target_regsets): Add new kind identifier.
Diffstat (limited to 'gdb/gdbserver/linux-low.c')
-rw-r--r--gdb/gdbserver/linux-low.c875
1 files changed, 788 insertions, 87 deletions
diff --git a/gdb/gdbserver/linux-low.c b/gdb/gdbserver/linux-low.c
index 6cfe0d5..c272fed 100644
--- a/gdb/gdbserver/linux-low.c
+++ b/gdb/gdbserver/linux-low.c
@@ -35,9 +35,32 @@
#include <stdlib.h>
#include <unistd.h>
-static CORE_ADDR linux_bp_reinsert;
+/* ``all_threads'' is keyed by the LWP ID - it should be the thread ID instead,
+ however. This requires changing the ID in place when we go from !using_threads
+ to using_threads, immediately.
+ ``all_processes'' is keyed by the process ID - which on Linux is (presently)
+ the same as the LWP ID. */
+
+struct inferior_list all_processes;
+
+/* FIXME this is a bit of a hack, and could be removed. */
+int stopping_threads;
+
+/* FIXME make into a target method? */
+int using_threads;
+
+static void linux_resume_one_process (struct inferior_list_entry *entry,
+ int step, int signal);
static void linux_resume (int step, int signal);
+static void stop_all_processes (void);
+static int linux_wait_for_event (struct thread_info *child);
+
+struct pending_signals
+{
+ int signal;
+ struct pending_signals *prev;
+};
#define PTRACE_ARG3_TYPE long
#define PTRACE_XFER_TYPE long
@@ -48,12 +71,64 @@ static int use_regsets_p = 1;
extern int errno;
-static int inferior_pid;
+int debug_threads = 0;
+
+#define pid_of(proc) ((proc)->head.id)
+
+/* FIXME: Delete eventually. */
+#define inferior_pid (pid_of (get_thread_process (current_inferior)))
+
+/* This function should only be called if the process got a SIGTRAP.
+ The SIGTRAP could mean several things.
+
+ On i386, where decr_pc_after_break is non-zero:
+ If we were single-stepping this process using PTRACE_SINGLESTEP,
+ we will get only the one SIGTRAP (even if the instruction we
+ stepped over was a breakpoint). The value of $eip will be the
+ next instruction.
+ If we continue the process using PTRACE_CONT, we will get a
+ SIGTRAP when we hit a breakpoint. The value of $eip will be
+ the instruction after the breakpoint (i.e. needs to be
+ decremented). If we report the SIGTRAP to GDB, we must also
+ report the undecremented PC. If we cancel the SIGTRAP, we
+ must resume at the decremented PC.
+
+ (Presumably, not yet tested) On a non-decr_pc_after_break machine
+ with hardware or kernel single-step:
+ If we single-step over a breakpoint instruction, our PC will
+ point at the following instruction. If we continue and hit a
+ breakpoint instruction, our PC will point at the breakpoint
+ instruction. */
+
+static CORE_ADDR
+get_stop_pc (void)
+{
+ CORE_ADDR stop_pc = (*the_low_target.get_pc) ();
+
+ if (get_thread_process (current_inferior)->stepping)
+ return stop_pc;
+ else
+ return stop_pc - the_low_target.decr_pc_after_break;
+}
-struct inferior_linux_data
+static void *
+add_process (int pid)
{
- int pid;
-};
+ struct process_info *process;
+
+ process = (struct process_info *) malloc (sizeof (*process));
+ memset (process, 0, sizeof (*process));
+
+ process->head.id = pid;
+
+ /* Default to tid == lwpid == pid. */
+ process->tid = pid;
+ process->lwpid = pid;
+
+ add_inferior_to_list (&all_processes, &process->head);
+
+ return process;
+}
/* Start an inferior process and returns its pid.
ALLARGS is a vector of program-name and args. */
@@ -61,7 +136,7 @@ struct inferior_linux_data
static int
linux_create_inferior (char *program, char **allargs)
{
- struct inferior_linux_data *tdata;
+ void *new_process;
int pid;
pid = fork ();
@@ -72,6 +147,8 @@ linux_create_inferior (char *program, char **allargs)
{
ptrace (PTRACE_TRACEME, 0, 0, 0);
+ signal (SIGRTMIN + 1, SIG_DFL);
+
execv (program, allargs);
fprintf (stderr, "Cannot exec %s: %s.\n", program,
@@ -80,22 +157,18 @@ linux_create_inferior (char *program, char **allargs)
_exit (0177);
}
- add_inferior (pid);
- tdata = (struct inferior_linux_data *) malloc (sizeof (*tdata));
- tdata->pid = pid;
- set_inferior_target_data (current_inferior, tdata);
+ new_process = add_process (pid);
+ add_thread (pid, new_process);
- /* FIXME remove */
- inferior_pid = pid;
return 0;
}
/* Attach to an inferior process. */
-static int
-linux_attach (int pid)
+void
+linux_attach_lwp (int pid, int tid)
{
- struct inferior_linux_data *tdata;
+ struct process_info *new_process;
if (ptrace (PTRACE_ATTACH, pid, 0, 0) != 0)
{
@@ -103,143 +176,712 @@ linux_attach (int pid)
errno < sys_nerr ? sys_errlist[errno] : "unknown error",
errno);
fflush (stderr);
- _exit (0177);
+
+ /* If we fail to attach to an LWP, just return. */
+ if (!using_threads)
+ _exit (0177);
+ return;
}
- add_inferior (pid);
- tdata = (struct inferior_linux_data *) malloc (sizeof (*tdata));
- tdata->pid = pid;
- set_inferior_target_data (current_inferior, tdata);
+ new_process = (struct process_info *) add_process (pid);
+ add_thread (tid, new_process);
+
+ /* The next time we wait for this LWP we'll see a SIGSTOP as PTRACE_ATTACH
+ brings it to a halt. We should ignore that SIGSTOP and resume the process
+ (unless this is the first process, in which case the flag will be cleared
+ in linux_attach).
+
+ 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 add_process added us to the end of the
+ list, and so the new thread has not yet reached wait_for_sigstop (but
+ will). */
+ if (! stopping_threads)
+ new_process->stop_expected = 1;
+}
+
+int
+linux_attach (int pid)
+{
+ struct process_info *process;
+
+ linux_attach_lwp (pid, pid);
+
+ /* Don't ignore the initial SIGSTOP if we just attached to this process. */
+ process = (struct process_info *) find_inferior_id (&all_processes, pid);
+ process->stop_expected = 0;
+
return 0;
}
/* Kill the inferior process. Make us have no inferior. */
static void
-linux_kill (void)
+linux_kill_one_process (struct inferior_list_entry *entry)
{
- if (inferior_pid == 0)
- return;
- ptrace (PTRACE_KILL, inferior_pid, 0, 0);
- wait (0);
- clear_inferiors ();
+ struct thread_info *thread = (struct thread_info *) entry;
+ struct process_info *process = get_thread_process (thread);
+ int wstat;
+
+ do
+ {
+ ptrace (PTRACE_KILL, pid_of (process), 0, 0);
+
+ /* Make sure it died. The loop is most likely unnecessary. */
+ wstat = linux_wait_for_event (thread);
+ } while (WIFSTOPPED (wstat));
}
/* Return nonzero if the given thread is still alive. */
+static void
+linux_kill (void)
+{
+ for_each_inferior (&all_threads, linux_kill_one_process);
+}
+
+static int
+linux_thread_alive (int tid)
+{
+ if (find_inferior_id (&all_threads, tid) != NULL)
+ return 1;
+ else
+ return 0;
+}
+
+/* Return nonzero if this process stopped at a breakpoint which
+ no longer appears to be inserted. Also adjust the PC
+ appropriately to resume where the breakpoint used to be. */
static int
-linux_thread_alive (int pid)
+check_removed_breakpoint (struct process_info *event_child)
{
+ CORE_ADDR stop_pc;
+ struct thread_info *saved_inferior;
+
+ if (event_child->pending_is_breakpoint == 0)
+ return 0;
+
+ if (debug_threads)
+ fprintf (stderr, "Checking for breakpoint.\n");
+
+ saved_inferior = current_inferior;
+ current_inferior = get_process_thread (event_child);
+
+ stop_pc = get_stop_pc ();
+
+ /* If the PC has changed since we stopped, then we shouldn't do
+ anything. This happens if, for instance, GDB handled the
+ decr_pc_after_break subtraction itself. */
+ if (stop_pc != event_child->pending_stop_pc)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Ignoring, PC was changed.\n");
+
+ event_child->pending_is_breakpoint = 0;
+ current_inferior = saved_inferior;
+ return 0;
+ }
+
+ /* If the breakpoint is still there, we will report hitting it. */
+ if ((*the_low_target.breakpoint_at) (stop_pc))
+ {
+ if (debug_threads)
+ fprintf (stderr, "Ignoring, breakpoint is still present.\n");
+ current_inferior = saved_inferior;
+ return 0;
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Removed breakpoint.\n");
+
+ /* For decr_pc_after_break targets, here is where we perform the
+ decrement. We go immediately from this function to resuming,
+ and can not safely call get_stop_pc () again. */
+ if (the_low_target.set_pc != NULL)
+ (*the_low_target.set_pc) (stop_pc);
+
+ /* We consumed the pending SIGTRAP. */
+ event_child->status_pending_p = 0;
+ event_child->status_pending = 0;
+
+ current_inferior = saved_inferior;
return 1;
}
+/* Return 1 if this process has an interesting status pending. This function
+ may silently resume an inferior process. */
static int
-linux_wait_for_one_inferior (struct inferior_info *child)
+status_pending_p (struct inferior_list_entry *entry, void *dummy)
+{
+ struct process_info *process = (struct process_info *) entry;
+
+ if (process->status_pending_p)
+ if (check_removed_breakpoint (process))
+ {
+ /* This thread was stopped at a breakpoint, and the breakpoint
+ is now gone. We were told to continue (or step...) all threads,
+ so GDB isn't trying to single-step past this breakpoint.
+ So instead of reporting the old SIGTRAP, pretend we got to
+ the breakpoint just after it was removed instead of just
+ before; resume the process. */
+ linux_resume_one_process (&process->head, 0, 0);
+ return 0;
+ }
+
+ return process->status_pending_p;
+}
+
+static void
+linux_wait_for_process (struct process_info **childp, int *wstatp)
{
- struct inferior_linux_data *child_data = inferior_target_data (child);
- int pid, wstat;
+ int ret;
+ int to_wait_for = -1;
+
+ if (*childp != NULL)
+ to_wait_for = (*childp)->lwpid;
while (1)
{
- pid = waitpid (child_data->pid, &wstat, 0);
+ ret = waitpid (to_wait_for, wstatp, WNOHANG);
+
+ if (ret == -1)
+ {
+ if (errno != ECHILD)
+ perror_with_name ("waitpid");
+ }
+ else if (ret > 0)
+ break;
+
+ ret = waitpid (to_wait_for, wstatp, WNOHANG | __WCLONE);
+
+ if (ret == -1)
+ {
+ if (errno != ECHILD)
+ perror_with_name ("waitpid (WCLONE)");
+ }
+ else if (ret > 0)
+ break;
+
+ usleep (1000);
+ }
+
+ if (debug_threads
+ && (!WIFSTOPPED (*wstatp)
+ || (WSTOPSIG (*wstatp) != 32
+ && WSTOPSIG (*wstatp) != 33)))
+ fprintf (stderr, "Got an event from %d (%x)\n", ret, *wstatp);
+
+ if (to_wait_for == -1)
+ *childp = (struct process_info *) find_inferior_id (&all_processes, ret);
+
+ (*childp)->stopped = 1;
+ (*childp)->pending_is_breakpoint = 0;
+
+ if (debug_threads
+ && WIFSTOPPED (*wstatp))
+ {
+ current_inferior = (struct thread_info *)
+ find_inferior_id (&all_threads, (*childp)->tid);
+ /* For testing only; i386_stop_pc prints out a diagnostic. */
+ if (the_low_target.get_pc != NULL)
+ get_stop_pc ();
+ }
+}
- if (pid != child_data->pid)
- perror_with_name ("wait");
+static int
+linux_wait_for_event (struct thread_info *child)
+{
+ CORE_ADDR stop_pc;
+ struct process_info *event_child;
+ int wstat;
+
+ /* Check for a process with a pending status. */
+ /* It is possible that the user changed the pending task's registers since
+ it stopped. We correctly handle the change of PC if we hit a breakpoint
+ (in check_removed_breakpoints); signals should be reported anyway. */
+ if (child == NULL)
+ {
+ event_child = (struct process_info *)
+ find_inferior (&all_processes, status_pending_p, NULL);
+ if (debug_threads && event_child)
+ fprintf (stderr, "Got a pending child %d\n", event_child->lwpid);
+ }
+ else
+ {
+ event_child = get_thread_process (child);
+ if (event_child->status_pending_p
+ && check_removed_breakpoint (event_child))
+ event_child = NULL;
+ }
- /* If this target supports breakpoints, see if we hit one. */
- if (the_low_target.stop_pc != NULL
- && WIFSTOPPED (wstat)
- && WSTOPSIG (wstat) == SIGTRAP)
+ if (event_child != NULL)
+ {
+ if (event_child->status_pending_p)
{
- CORE_ADDR stop_pc;
+ if (debug_threads)
+ fprintf (stderr, "Got an event from pending child %d (%04x)\n",
+ event_child->lwpid, event_child->status_pending);
+ wstat = event_child->status_pending;
+ event_child->status_pending_p = 0;
+ event_child->status_pending = 0;
+ current_inferior = get_process_thread (event_child);
+ return wstat;
+ }
+ }
+
+ /* 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. */
+ while (1)
+ {
+ if (child == NULL)
+ event_child = NULL;
+ else
+ event_child = get_thread_process (child);
+
+ linux_wait_for_process (&event_child, &wstat);
+
+ if (event_child == NULL)
+ error ("event from unknown child");
- if (linux_bp_reinsert != 0)
+ current_inferior = (struct thread_info *)
+ find_inferior_id (&all_threads, event_child->tid);
+
+ if (using_threads)
+ {
+ /* Check for thread exit. */
+ if (! WIFSTOPPED (wstat))
{
- reinsert_breakpoint (linux_bp_reinsert);
- linux_bp_reinsert = 0;
- linux_resume (0, 0);
+ if (debug_threads)
+ fprintf (stderr, "Thread %d (LWP %d) exiting\n",
+ event_child->tid, event_child->head.id);
+
+ /* If the last thread is exiting, just return. */
+ if (all_threads.head == all_threads.tail)
+ return wstat;
+
+ dead_thread_notify (event_child->tid);
+
+ remove_inferior (&all_processes, &event_child->head);
+ free (event_child);
+ remove_thread (current_inferior);
+ current_inferior = (struct thread_info *) all_threads.head;
+
+ /* If we were waiting for this particular child to do something...
+ well, it did something. */
+ if (child != NULL)
+ return wstat;
+
+ /* Wait for a more interesting event. */
continue;
}
- fetch_inferior_registers (0);
- stop_pc = (*the_low_target.stop_pc) ();
+ if (WIFSTOPPED (wstat)
+ && WSTOPSIG (wstat) == SIGSTOP
+ && event_child->stop_expected)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Expected stop.\n");
+ event_child->stop_expected = 0;
+ linux_resume_one_process (&event_child->head,
+ event_child->stepping, 0);
+ continue;
+ }
- if (check_breakpoints (stop_pc) != 0)
+ /* FIXME drow/2002-06-09: Get signal numbers from the inferior's
+ thread library? */
+ if (WIFSTOPPED (wstat)
+ && (WSTOPSIG (wstat) == SIGRTMIN
+ || WSTOPSIG (wstat) == SIGRTMIN + 1))
{
- if (the_low_target.set_pc != NULL)
- (*the_low_target.set_pc) (stop_pc);
+ if (debug_threads)
+ fprintf (stderr, "Ignored signal %d for %d (LWP %d).\n",
+ WSTOPSIG (wstat), event_child->tid,
+ event_child->head.id);
+ linux_resume_one_process (&event_child->head,
+ event_child->stepping,
+ WSTOPSIG (wstat));
+ continue;
+ }
+ }
- if (the_low_target.breakpoint_reinsert_addr == NULL)
- {
- linux_bp_reinsert = stop_pc;
- uninsert_breakpoint (stop_pc);
- linux_resume (1, 0);
- }
- else
- {
- reinsert_breakpoint_by_bp
- (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
- linux_resume (0, 0);
- }
+ /* If this event was not handled above, and is not a SIGTRAP, report
+ it. */
+ if (!WIFSTOPPED (wstat) || WSTOPSIG (wstat) != SIGTRAP)
+ return wstat;
- continue;
+ /* If this target does not support breakpoints, we simply report the
+ SIGTRAP; it's of no concern to us. */
+ if (the_low_target.get_pc == NULL)
+ return wstat;
+
+ stop_pc = get_stop_pc ();
+
+ /* bp_reinsert will only be set if we were single-stepping.
+ Notice that we will resume the process after hitting
+ a gdbserver breakpoint; single-stepping to/over one
+ is not supported (yet). */
+ if (event_child->bp_reinsert != 0)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Reinserted breakpoint.\n");
+ reinsert_breakpoint (event_child->bp_reinsert);
+ event_child->bp_reinsert = 0;
+
+ /* Clear the single-stepping flag and SIGTRAP as we resume. */
+ linux_resume_one_process (&event_child->head, 0, 0);
+ continue;
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Hit a (non-reinsert) breakpoint.\n");
+
+ if (check_breakpoints (stop_pc) != 0)
+ {
+ /* We hit one of our own breakpoints. We mark it as a pending
+ breakpoint, so that check_removed_breakpoints () will do the PC
+ adjustment for us at the appropriate time. */
+ event_child->pending_is_breakpoint = 1;
+ event_child->pending_stop_pc = stop_pc;
+
+ /* Now we need to put the breakpoint back. We continue in the event
+ loop instead of simply replacing the breakpoint right away,
+ in order to not lose signals sent to the thread that hit the
+ breakpoint. Unfortunately this increases the window where another
+ thread could sneak past the removed breakpoint. For the current
+ use of server-side breakpoints (thread creation) this is
+ acceptable; but it needs to be considered before this breakpoint
+ mechanism can be used in more general ways. For some breakpoints
+ it may be necessary to stop all other threads, but that should
+ be avoided where possible.
+
+ If breakpoint_reinsert_addr is NULL, that means that we can
+ use PTRACE_SINGLESTEP on this platform. Uninsert the breakpoint,
+ mark it for reinsertion, and single-step.
+
+ Otherwise, call the target function to figure out where we need
+ our temporary breakpoint, create it, and continue executing this
+ process. */
+ if (the_low_target.breakpoint_reinsert_addr == NULL)
+ {
+ event_child->bp_reinsert = stop_pc;
+ uninsert_breakpoint (stop_pc);
+ linux_resume_one_process (&event_child->head, 1, 0);
+ }
+ else
+ {
+ reinsert_breakpoint_by_bp
+ (stop_pc, (*the_low_target.breakpoint_reinsert_addr) ());
+ linux_resume_one_process (&event_child->head, 0, 0);
}
+
+ continue;
+ }
+
+ /* If we were single-stepping, we definitely want to report the
+ SIGTRAP. The single-step operation has completed, so also
+ clear the stepping flag; in general this does not matter,
+ because the SIGTRAP will be reported to the client, which
+ will give us a new action for this thread, but clear it for
+ consistency anyway. It's safe to clear the stepping flag
+ because the only consumer of get_stop_pc () after this point
+ is check_removed_breakpoints, and pending_is_breakpoint is not
+ set. It might be wiser to use a step_completed flag instead. */
+ if (event_child->stepping)
+ {
+ event_child->stepping = 0;
+ return wstat;
+ }
+
+ /* A SIGTRAP that we can't explain. It may have been a breakpoint.
+ Check if it is a breakpoint, and if so mark the process information
+ accordingly. This will handle both the necessary fiddling with the
+ PC on decr_pc_after_break targets and suppressing extra threads
+ hitting a breakpoint if two hit it at once and then GDB removes it
+ after the first is reported. Arguably it would be better to report
+ multiple threads hitting breakpoints simultaneously, but the current
+ remote protocol does not allow this. */
+ if ((*the_low_target.breakpoint_at) (stop_pc))
+ {
+ event_child->pending_is_breakpoint = 1;
+ event_child->pending_stop_pc = stop_pc;
}
return wstat;
}
+
/* NOTREACHED */
return 0;
}
-/* Wait for process, returns status */
+/* Wait for process, returns status. */
static unsigned char
linux_wait (char *status)
{
int w;
+ struct thread_info *child = NULL;
+
+retry:
+ /* If we were only supposed to resume one thread, only wait for
+ that thread - if it's still alive. If it died, however - which
+ can happen if we're coming from the thread death case below -
+ then we need to make sure we restart the other threads. We could
+ pick a thread at random or restart all; restarting all is less
+ arbitrary. */
+ if (cont_thread > 0)
+ {
+ child = (struct thread_info *) find_inferior_id (&all_threads,
+ cont_thread);
+
+ /* No stepping, no signal - unless one is pending already, of course. */
+ if (child == NULL)
+ linux_resume (0, 0);
+ }
enable_async_io ();
- w = linux_wait_for_one_inferior (current_inferior);
+ w = linux_wait_for_event (child);
+ stop_all_processes ();
disable_async_io ();
- if (WIFEXITED (w))
+ /* If we are waiting for a particular child, and it exited,
+ linux_wait_for_event will return its exit status. Similarly if
+ the last child exited. If this is not the last child, however,
+ do not report it as exited until there is a 'thread exited' response
+ available in the remote protocol. Instead, just wait for another event.
+ This should be safe, because if the thread crashed we will already
+ have reported the termination signal to GDB; that should stop any
+ in-progress stepping operations, etc.
+
+ Report the exit status of the last thread to exit. This matches
+ LinuxThreads' behavior. */
+
+ if (all_threads.head == all_threads.tail)
{
- fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
- *status = 'W';
- clear_inferiors ();
- return ((unsigned char) WEXITSTATUS (w));
+ if (WIFEXITED (w))
+ {
+ fprintf (stderr, "\nChild exited with retcode = %x \n", WEXITSTATUS (w));
+ *status = 'W';
+ clear_inferiors ();
+ return ((unsigned char) WEXITSTATUS (w));
+ }
+ else if (!WIFSTOPPED (w))
+ {
+ fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
+ clear_inferiors ();
+ *status = 'X';
+ return ((unsigned char) WTERMSIG (w));
+ }
}
- else if (!WIFSTOPPED (w))
+ else
{
- fprintf (stderr, "\nChild terminated with signal = %x \n", WTERMSIG (w));
- clear_inferiors ();
- *status = 'X';
- return ((unsigned char) WTERMSIG (w));
+ if (!WIFSTOPPED (w))
+ goto retry;
}
- fetch_inferior_registers (0);
-
*status = 'T';
return ((unsigned char) WSTOPSIG (w));
}
+static void
+send_sigstop (struct inferior_list_entry *entry)
+{
+ struct process_info *process = (struct process_info *) entry;
+
+ if (process->stopped)
+ return;
+
+ /* If we already have a pending stop signal for this process, don't
+ send another. */
+ if (process->stop_expected)
+ {
+ process->stop_expected = 0;
+ return;
+ }
+
+ if (debug_threads)
+ fprintf (stderr, "Sending sigstop to process %d\n", process->head.id);
+
+ kill (process->head.id, SIGSTOP);
+ process->sigstop_sent = 1;
+}
+
+static void
+wait_for_sigstop (struct inferior_list_entry *entry)
+{
+ struct process_info *process = (struct process_info *) entry;
+ struct thread_info *saved_inferior, *thread;
+ int wstat, saved_tid;
+
+ if (process->stopped)
+ return;
+
+ saved_inferior = current_inferior;
+ saved_tid = ((struct inferior_list_entry *) saved_inferior)->id;
+ thread = (struct thread_info *) find_inferior_id (&all_threads,
+ process->tid);
+ wstat = linux_wait_for_event (thread);
+
+ /* If we stopped with a non-SIGSTOP signal, save it for later
+ and record the pending SIGSTOP. If the process exited, just
+ return. */
+ if (WIFSTOPPED (wstat)
+ && WSTOPSIG (wstat) != SIGSTOP)
+ {
+ if (debug_threads)
+ fprintf (stderr, "Stopped with non-sigstop signal\n");
+ process->status_pending_p = 1;
+ process->status_pending = wstat;
+ process->stop_expected = 1;
+ }
+
+ if (linux_thread_alive (saved_tid))
+ current_inferior = saved_inferior;
+ else
+ {
+ if (debug_threads)
+ fprintf (stderr, "Previously current thread died.\n");
+
+ /* Set a valid thread as current. */
+ set_desired_inferior (0);
+ }
+}
+
+static void
+stop_all_processes (void)
+{
+ stopping_threads = 1;
+ for_each_inferior (&all_processes, send_sigstop);
+ for_each_inferior (&all_processes, wait_for_sigstop);
+ stopping_threads = 0;
+}
+
/* Resume execution of the inferior process.
If STEP is nonzero, single-step it.
If SIGNAL is nonzero, give it that signal. */
static void
-linux_resume (int step, int signal)
+linux_resume_one_process (struct inferior_list_entry *entry,
+ int step, int signal)
{
+ struct process_info *process = (struct process_info *) entry;
+ struct thread_info *saved_inferior;
+
+ if (process->stopped == 0)
+ return;
+
+ /* If we have pending signals or status, and a new signal, enqueue the
+ signal. Also enqueue the signal if we are waiting to reinsert a
+ breakpoint; it will be picked up again below. */
+ if (signal != 0
+ && (process->status_pending_p || process->pending_signals != NULL
+ || process->bp_reinsert != 0))
+ {
+ struct pending_signals *p_sig;
+ p_sig = malloc (sizeof (*p_sig));
+ p_sig->prev = process->pending_signals;
+ p_sig->signal = signal;
+ process->pending_signals = p_sig;
+ }
+
+ if (process->status_pending_p)
+ return;
+
+ saved_inferior = current_inferior;
+ current_inferior = get_process_thread (process);
+
+ if (debug_threads)
+ fprintf (stderr, "Resuming process %d (%s, signal %d, stop %s)\n", inferior_pid,
+ step ? "step" : "continue", signal,
+ process->stop_expected ? "expected" : "not expected");
+
+ /* 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_process) but not enough for
+ complete correctness, so it won't solve that problem. It may be
+ worthwhile just to solve this one, however. */
+ if (process->bp_reinsert != 0)
+ {
+ if (debug_threads)
+ fprintf (stderr, " pending reinsert at %08lx", (long)process->bp_reinsert);
+ if (step == 0)
+ fprintf (stderr, "BAD - reinserting but not stepping.\n");
+ step = 1;
+
+ /* Postpone any pending signal. It was enqueued above. */
+ signal = 0;
+ }
+
+ check_removed_breakpoint (process);
+
+ if (debug_threads && the_low_target.get_pc != NULL)
+ {
+ fprintf (stderr, " ");
+ (long) (*the_low_target.get_pc) ();
+ }
+
+ /* If we have pending signals, consume one unless we are trying to reinsert
+ a breakpoint. */
+ if (process->pending_signals != NULL && process->bp_reinsert == 0)
+ {
+ struct pending_signals **p_sig;
+
+ p_sig = &process->pending_signals;
+ while ((*p_sig)->prev != NULL)
+ p_sig = &(*p_sig)->prev;
+
+ signal = (*p_sig)->signal;
+ free (*p_sig);
+ *p_sig = NULL;
+ }
+
+ regcache_invalidate_one ((struct inferior_list_entry *)
+ get_process_thread (process));
errno = 0;
- ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, inferior_pid, 1, signal);
+ process->stopped = 0;
+ process->stepping = step;
+ ptrace (step ? PTRACE_SINGLESTEP : PTRACE_CONT, process->lwpid, 0, signal);
+
+ current_inferior = saved_inferior;
if (errno)
perror_with_name ("ptrace");
}
+/* This function is called once per process other than the first
+ one. The first process we are told the signal to continue
+ with, and whether to step or continue; for all others, any
+ existing signals will be marked in status_pending_p to be
+ reported momentarily, and we preserve the stepping flag. */
+static void
+linux_continue_one_process (struct inferior_list_entry *entry)
+{
+ struct process_info *process;
-#ifdef HAVE_LINUX_USRREGS
+ process = (struct process_info *) entry;
+ linux_resume_one_process (entry, process->stepping, 0);
+}
+
+static void
+linux_resume (int step, int signal)
+{
+ struct process_info *process;
+
+ process = get_thread_process (current_inferior);
+
+ /* If the current process has a status pending, this signal will
+ be enqueued and sent later. */
+ linux_resume_one_process (&process->head, step, signal);
-#define REGISTER_RAW_SIZE(regno) register_size((regno))
+ if (cont_thread == 0 || cont_thread == -1)
+ for_each_inferior (&all_processes, linux_continue_one_process);
+}
+
+#ifdef HAVE_LINUX_USRREGS
int
register_addr (int regnum)
@@ -262,6 +904,7 @@ fetch_register (int regno)
{
CORE_ADDR regaddr;
register int i;
+ char *buf;
if (regno >= the_low_target.num_regs)
return;
@@ -271,10 +914,11 @@ fetch_register (int regno)
regaddr = register_addr (regno);
if (regaddr == -1)
return;
- for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
+ buf = alloca (register_size (regno));
+ for (i = 0; i < register_size (regno); i += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
- *(PTRACE_XFER_TYPE *) (register_data (regno) + i) =
+ *(PTRACE_XFER_TYPE *) (buf + i) =
ptrace (PTRACE_PEEKUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr, 0);
regaddr += sizeof (PTRACE_XFER_TYPE);
if (errno != 0)
@@ -288,6 +932,8 @@ fetch_register (int regno)
goto error_exit;
}
}
+ supply_register (regno, buf);
+
error_exit:;
}
@@ -310,6 +956,7 @@ usr_store_inferior_registers (int regno)
{
CORE_ADDR regaddr;
int i;
+ char *buf;
if (regno >= 0)
{
@@ -323,11 +970,13 @@ usr_store_inferior_registers (int regno)
if (regaddr == -1)
return;
errno = 0;
- for (i = 0; i < REGISTER_RAW_SIZE (regno); i += sizeof (PTRACE_XFER_TYPE))
+ buf = alloca (register_size (regno));
+ collect_register (regno, buf);
+ for (i = 0; i < register_size (regno); i += sizeof (PTRACE_XFER_TYPE))
{
errno = 0;
ptrace (PTRACE_POKEUSER, inferior_pid, (PTRACE_ARG3_TYPE) regaddr,
- *(int *) (register_data (regno) + i));
+ *(int *) (buf + i));
if (errno != 0)
{
if ((*the_low_target.cannot_store_register) (regno) == 0)
@@ -345,7 +994,7 @@ usr_store_inferior_registers (int regno)
}
else
for (regno = 0; regno < the_low_target.num_regs; regno++)
- store_inferior_registers (regno);
+ usr_store_inferior_registers (regno);
}
#endif /* HAVE_LINUX_USRREGS */
@@ -354,7 +1003,7 @@ usr_store_inferior_registers (int regno)
#ifdef HAVE_LINUX_REGSETS
static int
-regsets_fetch_inferior_registers (void)
+regsets_fetch_inferior_registers ()
{
struct regset_info *regset;
@@ -392,7 +1041,10 @@ regsets_fetch_inferior_registers (void)
}
else
{
- perror ("Warning: ptrace(regsets_fetch_inferior_registers)");
+ char s[256];
+ sprintf (s, "ptrace(regsets_fetch_inferior_registers) PID=%d",
+ inferior_pid);
+ perror (s);
}
}
regset->store_function (buf);
@@ -402,7 +1054,7 @@ regsets_fetch_inferior_registers (void)
}
static int
-regsets_store_inferior_registers (void)
+regsets_store_inferior_registers ()
{
struct regset_info *regset;
@@ -528,6 +1180,11 @@ linux_write_memory (CORE_ADDR memaddr, const char *myaddr, int len)
register PTRACE_XFER_TYPE *buffer = (PTRACE_XFER_TYPE *) alloca (count * sizeof (PTRACE_XFER_TYPE));
extern int errno;
+ if (debug_threads)
+ {
+ fprintf (stderr, "Writing %02x to %08lx\n", (unsigned)myaddr[0], (long)memaddr);
+ }
+
/* Fill start and end extra bytes of buffer with existing memory data. */
buffer[0] = ptrace (PTRACE_PEEKTEXT, inferior_pid,
@@ -562,7 +1219,40 @@ linux_write_memory (CORE_ADDR memaddr, const char *myaddr, int len)
static void
linux_look_up_symbols (void)
{
- /* Don't need to look up any symbols yet. */
+#ifdef USE_THREAD_DB
+ if (using_threads)
+ return;
+
+ using_threads = thread_db_init ();
+#endif
+}
+
+/* Return 1 if this process is not stopped. */
+static int
+unstopped_p (struct inferior_list_entry *entry, void *dummy)
+{
+ struct process_info *process = (struct process_info *) entry;
+
+ if (process->stopped)
+ return 0;
+
+ return 1;
+}
+
+static int
+linux_signal_pid ()
+{
+ struct inferior_list_entry *process;
+
+ process = find_inferior (&all_processes, unstopped_p, NULL);
+
+ if (process == NULL)
+ {
+ warning ("no unstopped process");
+ return inferior_pid;
+ }
+
+ return pid_of ((struct process_info *) process);
}
@@ -578,13 +1268,24 @@ static struct target_ops linux_target_ops = {
linux_read_memory,
linux_write_memory,
linux_look_up_symbols,
+ linux_signal_pid,
};
+static void
+linux_init_signals ()
+{
+ /* FIXME drow/2002-06-09: As above, we should check with LinuxThreads
+ to find what the cancel signal actually is. */
+ signal (SIGRTMIN+1, SIG_IGN);
+}
+
void
initialize_low (void)
{
+ using_threads = 0;
set_target_ops (&linux_target_ops);
set_breakpoint_data (the_low_target.breakpoint,
the_low_target.breakpoint_len);
init_registers ();
+ linux_init_signals ();
}