* lin-lwp.c: Delete file.
* linux-nat.c: Include "gdb_assert.h", "gdb_string.h", <unistd.h>,
<sys/syscall.h>, "gdbthread.h", "gdbcmd.h", "regcache.h".
(status_to_str, init_lwp_list, add_lwp, delete_lwp)
(find_lwp_pid, iterate_over_lwps, lin_lwp_attach_lwp)
(linux_nat_attach, detach_callback, linux_nat_detach)
(resume_callback, resume_clear_callback, linux_nat_resume)
(kill_lwp, linux_nat_handle_extended, wait_lwp, stop_callback)
(stop_wait_callback, linux_nat_has_pending, flush_callback)
(status_callback, running_callback, count_events_callback)
(select_singlestep_lwp_callback, select_event_lwp_callback)
(cancel_breakpoints_callback, select_event_lwp, resumed_callback)
(child_wait, stop_and_resume_callback, linux_nat_wait)
(kill_callback, kill_wait_callback, linux_nat_kill)
(linux_nat_create_inferior, linux_nat_mourn_inferior)
(linux_nat_xfer_memory, linux_nat_thread_alive)
(linux_nat_pid_to_str, init_linux_nat_ops, sigchld_handler)
(_initialize_linux_nat): New functions.
* Makefile.in: Update all dependencies.
* config/sparc/linux64.mh (NATDEPFILES): Remove lin-lwp.o.
* config/sparc/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/s390/s390.mh (NATDEPFILES): Remove lin-lwp.o.
* config/powerpc/ppc64-linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/powerpc/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/pa/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/mips/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/m68k/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/ia64/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/i386/linux64.mh (NATDEPFILES): Remove lin-lwp.o.
* config/i386/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/arm/linux.mh (NATDEPFILES): Remove lin-lwp.o.
* config/alpha/alpha-linux.mh (NATDEPFILES): Remove lin-lwp.o.
+2004-09-16 Andrew Cagney <cagney@gnu.org>
+
+ * lin-lwp.c: Delete file.
+ * linux-nat.c: Include "gdb_assert.h", "gdb_string.h", <unistd.h>,
+ <sys/syscall.h>, "gdbthread.h", "gdbcmd.h", "regcache.h".
+ (status_to_str, init_lwp_list, add_lwp, delete_lwp)
+ (find_lwp_pid, iterate_over_lwps, lin_lwp_attach_lwp)
+ (linux_nat_attach, detach_callback, linux_nat_detach)
+ (resume_callback, resume_clear_callback, linux_nat_resume)
+ (kill_lwp, linux_nat_handle_extended, wait_lwp, stop_callback)
+ (stop_wait_callback, linux_nat_has_pending, flush_callback)
+ (status_callback, running_callback, count_events_callback)
+ (select_singlestep_lwp_callback, select_event_lwp_callback)
+ (cancel_breakpoints_callback, select_event_lwp, resumed_callback)
+ (child_wait, stop_and_resume_callback, linux_nat_wait)
+ (kill_callback, kill_wait_callback, linux_nat_kill)
+ (linux_nat_create_inferior, linux_nat_mourn_inferior)
+ (linux_nat_xfer_memory, linux_nat_thread_alive)
+ (linux_nat_pid_to_str, init_linux_nat_ops, sigchld_handler)
+ (_initialize_linux_nat): New functions.
+ * Makefile.in: Update all dependencies.
+ * config/sparc/linux64.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/sparc/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/s390/s390.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/powerpc/ppc64-linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/powerpc/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/pa/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/mips/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/m68k/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/ia64/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/i386/linux64.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/i386/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/arm/linux.mh (NATDEPFILES): Remove lin-lwp.o.
+ * config/alpha/alpha-linux.mh (NATDEPFILES): Remove lin-lwp.o.
+
2004-09-27 Mark Kettenis <kettenis@gnu.org>
* config/i386/fbsd64.mh, config/i386/nbsd64.mh,
lin-lwp.o: lin-lwp.c $(defs_h) $(gdb_assert_h) $(gdb_string_h) $(gdb_wait_h) \
$(gdbthread_h) $(inferior_h) $(target_h) $(regcache_h) $(gdbcmd_h) \
$(linux_nat_h)
-linux-nat.o: linux-nat.c $(defs_h) $(inferior_h) $(target_h) $(gdb_wait_h) \
- $(linux_nat_h)
+linux-nat.o: linux-nat.c $(defs_h) $(inferior_h) $(target_h) $(gdb_string_h) \
+ $(gdb_wait_h) $(gdb_assert_h) $(linux_nat_h) $(gdbthread_h) \
+ $(gdbcmd_h) $(regcache_h)
linux-proc.o: linux-proc.c $(defs_h) $(inferior_h) $(gdb_stat_h) \
$(regcache_h) $(gregset_h) $(gdbcore_h) $(gdbthread_h) $(elf_bfd_h) \
$(cli_decode_h) $(gdb_string_h) $(linux_nat_h)
# Host: Little-endian Alpha running Linux
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o corelow.o alpha-nat.o linux-proc.o \
- fork-child.o proc-service.o thread-db.o lin-lwp.o gcore.o \
+ fork-child.o proc-service.o thread-db.o gcore.o \
linux-nat.o
# The dynamically loaded libthread_db needs access to symbols in the
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o corelow.o \
core-regset.o arm-linux-nat.o linux-proc.o gcore.o \
- proc-service.o thread-db.o lin-lwp.o linux-nat.o
+ proc-service.o thread-db.o linux-nat.o
LOADLIBES= -ldl -rdynamic
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o corelow.o linux-proc.o \
core-aout.o i386-nat.o i386-linux-nat.o \
- proc-service.o thread-db.o lin-lwp.o linux-proc.o gcore.o \
+ proc-service.o thread-db.o linux-proc.o gcore.o \
linux-nat.o
# The dynamically loaded libthread_db needs access to symbols in the
# Host: GNU/Linux x86-64
NATDEPFILES= infptrace.o inftarg.o fork-child.o \
i386-nat.o amd64-nat.o amd64-linux-nat.o linux-nat.o \
- proc-service.o thread-db.o lin-lwp.o linux-proc.o gcore.o
+ proc-service.o thread-db.o linux-proc.o gcore.o
NAT_FILE= nm-linux64.h
# The dynamically loaded libthread_db needs access to symbols in the
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o corelow.o gcore.o \
core-aout.o core-regset.o ia64-linux-nat.o linux-proc.o \
- proc-service.o thread-db.o lin-lwp.o linux-nat.o
+ proc-service.o thread-db.o linux-nat.o
LOADLIBES = -ldl -rdynamic
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o \
corelow.o core-aout.o m68klinux-nat.o linux-proc.o gcore.o \
- proc-service.o thread-db.o lin-lwp.o linux-nat.o
+ proc-service.o thread-db.o linux-nat.o
# The dynamically loaded libthread_db needs access to symbols in the
# gdb executable.
# Host: Linux/MIPS
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o mips-linux-nat.o \
- thread-db.o lin-lwp.o proc-service.o linux-proc.o gcore.o \
+ thread-db.o proc-service.o linux-proc.o gcore.o \
linux-nat.o
LOADLIBES = -ldl -rdynamic
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o corelow.o gcore.o \
core-regset.o hppa-linux-nat.o linux-proc.o \
- proc-service.o thread-db.o lin-lwp.o linux-nat.o
+ proc-service.o thread-db.o linux-nat.o
LOADLIBES = -ldl -rdynamic
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o linux-proc.o \
- ppc-linux-nat.o proc-service.o thread-db.o lin-lwp.o \
+ ppc-linux-nat.o proc-service.o thread-db.o \
gcore.o linux-nat.o
LOADLIBES = -ldl -rdynamic
NAT_FILE= nm-ppc64-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o linux-proc.o \
- ppc-linux-nat.o proc-service.o thread-db.o lin-lwp.o \
+ ppc-linux-nat.o proc-service.o thread-db.o \
gcore.o linux-nat.o
# The PowerPC has severe limitations on TOC size, and uses them even
# Host: S390, running Linux
NAT_FILE= nm-linux.h
NATDEPFILES= infptrace.o inftarg.o fork-child.o corelow.o s390-nat.o \
- linux-proc.o gcore.o thread-db.o lin-lwp.o proc-service.o linux-nat.o
+ linux-proc.o gcore.o thread-db.o proc-service.o linux-nat.o
LOADLIBES = -ldl -rdynamic
NATDEPFILES= sparc-nat.o sparc-sol2-nat.o \
corelow.o core-regset.o fork-child.o \
infptrace.o inftarg.o \
- proc-service.o thread-db.o lin-lwp.o \
+ proc-service.o thread-db.o \
linux-proc.o gcore.o linux-nat.o
# The dynamically loaded libthread_db needs access to symbols in the
NATDEPFILES= sparc-nat.o sparc64-nat.o sparc-sol2-nat.o sparc64-linux-nat.o \
corelow.o core-regset.o \
fork-child.o infptrace.o inftarg.o \
- proc-service.o thread-db.o lin-lwp.o \
+ proc-service.o thread-db.o \
linux-proc.o gcore.o linux-nat.o
# The dynamically loaded libthread_db needs access to symbols in the
+++ /dev/null
-/* Multi-threaded debugging support for GNU/Linux (LWP layer).
- Copyright 2000, 2001, 2002, 2003, 2004 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 2 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, write to the Free Software
- Foundation, Inc., 59 Temple Place - Suite 330,
- Boston, MA 02111-1307, USA. */
-
-#include "defs.h"
-
-#include "gdb_assert.h"
-#include "gdb_string.h"
-#include <errno.h>
-#include <signal.h>
-#ifdef HAVE_TKILL_SYSCALL
-#include <unistd.h>
-#include <sys/syscall.h>
-#endif
-#include <sys/ptrace.h>
-#include "gdb_wait.h"
-
-#include "gdbthread.h"
-#include "inferior.h"
-#include "target.h"
-#include "regcache.h"
-#include "gdbcmd.h"
-
-static int debug_lin_lwp;
-extern char *strsignal (int sig);
-
-#include "linux-nat.h"
-
-/* On GNU/Linux there are no real LWP's. The closest thing to LWP's
- are processes sharing the same VM space. A multi-threaded process
- is basically a group of such processes. However, such a grouping
- is almost entirely a user-space issue; the kernel doesn't enforce
- such a grouping at all (this might change in the future). In
- general, we'll rely on the threads library (i.e. the GNU/Linux
- Threads library) to provide such a grouping.
-
- It is perfectly well possible to write a multi-threaded application
- without the assistance of a threads library, by using the clone
- system call directly. This module should be able to give some
- rudimentary support for debugging such applications if developers
- specify the CLONE_PTRACE flag in the clone system call, and are
- using the Linux kernel 2.4 or above.
-
- Note that there are some peculiarities in GNU/Linux that affect
- this code:
-
- - In general one should specify the __WCLONE flag to waitpid in
- order to make it report events for any of the cloned processes
- (and leave it out for the initial process). However, if a cloned
- process has exited the exit status is only reported if the
- __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
- we cannot use it since GDB must work on older systems too.
-
- - When a traced, cloned process exits and is waited for by the
- debugger, the kernel reassigns it to the original parent and
- keeps it around as a "zombie". Somehow, the GNU/Linux Threads
- library doesn't notice this, which leads to the "zombie problem":
- When debugged a multi-threaded process that spawns a lot of
- threads will run out of processes, even if the threads exit,
- because the "zombies" stay around. */
-
-/* List of known LWPs. */
-static struct lwp_info *lwp_list;
-
-/* Number of LWPs in the list. */
-static int num_lwps;
-
-/* Non-zero if we're running in "threaded" mode. */
-static int threaded;
-\f
-
-#define GET_LWP(ptid) ptid_get_lwp (ptid)
-#define GET_PID(ptid) ptid_get_pid (ptid)
-#define is_lwp(ptid) (GET_LWP (ptid) != 0)
-#define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0)
-
-/* If the last reported event was a SIGTRAP, this variable is set to
- the process id of the LWP/thread that got it. */
-ptid_t trap_ptid;
-\f
-
-/* This module's target-specific operations. */
-static struct target_ops lin_lwp_ops;
-
-/* The standard child operations. */
-extern struct target_ops child_ops;
-
-/* Since we cannot wait (in lin_lwp_wait) for the initial process and
- any cloned processes with a single call to waitpid, we have to use
- the WNOHANG flag and call waitpid in a loop. To optimize
- things a bit we use `sigsuspend' to wake us up when a process has
- something to report (it will send us a SIGCHLD if it has). To make
- this work we have to juggle with the signal mask. We save the
- original signal mask such that we can restore it before creating a
- new process in order to avoid blocking certain signals in the
- inferior. We then block SIGCHLD during the waitpid/sigsuspend
- loop. */
-
-/* Original signal mask. */
-static sigset_t normal_mask;
-
-/* Signal mask for use with sigsuspend in lin_lwp_wait, initialized in
- _initialize_lin_lwp. */
-static sigset_t suspend_mask;
-
-/* Signals to block to make that sigsuspend work. */
-static sigset_t blocked_mask;
-\f
-
-/* Prototypes for local functions. */
-static int stop_wait_callback (struct lwp_info *lp, void *data);
-static int lin_lwp_thread_alive (ptid_t ptid);
-\f
-/* Convert wait status STATUS to a string. Used for printing debug
- messages only. */
-
-static char *
-status_to_str (int status)
-{
- static char buf[64];
-
- if (WIFSTOPPED (status))
- snprintf (buf, sizeof (buf), "%s (stopped)",
- strsignal (WSTOPSIG (status)));
- else if (WIFSIGNALED (status))
- snprintf (buf, sizeof (buf), "%s (terminated)",
- strsignal (WSTOPSIG (status)));
- else
- snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
-
- return buf;
-}
-\f
-/* Initialize the list of LWPs. Note that this module, contrary to
- what GDB's generic threads layer does for its thread list,
- re-initializes the LWP lists whenever we mourn or detach (which
- doesn't involve mourning) the inferior. */
-
-static void
-init_lwp_list (void)
-{
- struct lwp_info *lp, *lpnext;
-
- for (lp = lwp_list; lp; lp = lpnext)
- {
- lpnext = lp->next;
- xfree (lp);
- }
-
- lwp_list = NULL;
- num_lwps = 0;
- threaded = 0;
-}
-
-/* Add the LWP specified by PID to the list. If this causes the
- number of LWPs to become larger than one, go into "threaded" mode.
- Return a pointer to the structure describing the new LWP. */
-
-static struct lwp_info *
-add_lwp (ptid_t ptid)
-{
- struct lwp_info *lp;
-
- gdb_assert (is_lwp (ptid));
-
- lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
-
- memset (lp, 0, sizeof (struct lwp_info));
-
- lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
-
- lp->ptid = ptid;
-
- lp->next = lwp_list;
- lwp_list = lp;
- if (++num_lwps > 1)
- threaded = 1;
-
- return lp;
-}
-
-/* Remove the LWP specified by PID from the list. */
-
-static void
-delete_lwp (ptid_t ptid)
-{
- struct lwp_info *lp, *lpprev;
-
- lpprev = NULL;
-
- for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
- if (ptid_equal (lp->ptid, ptid))
- break;
-
- if (!lp)
- return;
-
- /* We don't go back to "non-threaded" mode if the number of threads
- becomes less than two. */
- num_lwps--;
-
- if (lpprev)
- lpprev->next = lp->next;
- else
- lwp_list = lp->next;
-
- xfree (lp);
-}
-
-/* Return a pointer to the structure describing the LWP corresponding
- to PID. If no corresponding LWP could be found, return NULL. */
-
-static struct lwp_info *
-find_lwp_pid (ptid_t ptid)
-{
- struct lwp_info *lp;
- int lwp;
-
- if (is_lwp (ptid))
- lwp = GET_LWP (ptid);
- else
- lwp = GET_PID (ptid);
-
- for (lp = lwp_list; lp; lp = lp->next)
- if (lwp == GET_LWP (lp->ptid))
- return lp;
-
- return NULL;
-}
-
-/* Call CALLBACK with its second argument set to DATA for every LWP in
- the list. If CALLBACK returns 1 for a particular LWP, return a
- pointer to the structure describing that LWP immediately.
- Otherwise return NULL. */
-
-struct lwp_info *
-iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data)
-{
- struct lwp_info *lp, *lpnext;
-
- for (lp = lwp_list; lp; lp = lpnext)
- {
- lpnext = lp->next;
- if ((*callback) (lp, data))
- return lp;
- }
-
- return NULL;
-}
-\f
-
-#if 0
-static void
-lin_lwp_open (char *args, int from_tty)
-{
- push_target (&lin_lwp_ops);
-}
-#endif
-
-/* Attach to the LWP specified by PID. If VERBOSE is non-zero, print
- a message telling the user that a new LWP has been added to the
- process. */
-
-void
-lin_lwp_attach_lwp (ptid_t ptid, int verbose)
-{
- struct lwp_info *lp, *found_lp;
-
- gdb_assert (is_lwp (ptid));
-
- /* Make sure SIGCHLD is blocked. We don't want SIGCHLD events
- to interrupt either the ptrace() or waitpid() calls below. */
- if (!sigismember (&blocked_mask, SIGCHLD))
- {
- sigaddset (&blocked_mask, SIGCHLD);
- sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
- }
-
- if (verbose)
- printf_filtered ("[New %s]\n", target_pid_to_str (ptid));
-
- found_lp = lp = find_lwp_pid (ptid);
- if (lp == NULL)
- lp = add_lwp (ptid);
-
- /* We assume that we're already attached to any LWP that has an id
- equal to the overall process id, and to any LWP that is already
- in our list of LWPs. If we're not seeing exit events from threads
- and we've had PID wraparound since we last tried to stop all threads,
- this assumption might be wrong; fortunately, this is very unlikely
- to happen. */
- if (GET_LWP (ptid) != GET_PID (ptid) && found_lp == NULL)
- {
- pid_t pid;
- int status;
-
- if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0)
- error ("Can't attach %s: %s", target_pid_to_str (ptid),
- safe_strerror (errno));
-
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
- target_pid_to_str (ptid));
-
- pid = waitpid (GET_LWP (ptid), &status, 0);
- if (pid == -1 && errno == ECHILD)
- {
- /* Try again with __WCLONE to check cloned processes. */
- pid = waitpid (GET_LWP (ptid), &status, __WCLONE);
- lp->cloned = 1;
- }
-
- gdb_assert (pid == GET_LWP (ptid)
- && WIFSTOPPED (status) && WSTOPSIG (status));
-
- child_post_attach (pid);
-
- lp->stopped = 1;
-
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "LLAL: waitpid %s received %s\n",
- target_pid_to_str (ptid),
- status_to_str (status));
- }
- }
- else
- {
- /* We assume that the LWP representing the original process
- is already stopped. Mark it as stopped in the data structure
- that the lin-lwp layer uses to keep track of threads. Note
- that this won't have already been done since the main thread
- will have, we assume, been stopped by an attach from a
- different layer. */
- lp->stopped = 1;
- }
-}
-
-static void
-lin_lwp_attach (char *args, int from_tty)
-{
- struct lwp_info *lp;
- pid_t pid;
- int status;
-
- /* FIXME: We should probably accept a list of process id's, and
- attach all of them. */
- child_ops.to_attach (args, from_tty);
-
- /* Add the initial process as the first LWP to the list. */
- lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid)));
-
- /* Make sure the initial process is stopped. The user-level threads
- layer might want to poke around in the inferior, and that won't
- work if things haven't stabilized yet. */
- pid = waitpid (GET_PID (inferior_ptid), &status, 0);
- if (pid == -1 && errno == ECHILD)
- {
- warning ("%s is a cloned process", target_pid_to_str (inferior_ptid));
-
- /* Try again with __WCLONE to check cloned processes. */
- pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE);
- lp->cloned = 1;
- }
-
- gdb_assert (pid == GET_PID (inferior_ptid)
- && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP);
-
- lp->stopped = 1;
-
- /* Fake the SIGSTOP that core GDB expects. */
- lp->status = W_STOPCODE (SIGSTOP);
- lp->resumed = 1;
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "LLA: waitpid %ld, faking SIGSTOP\n", (long) pid);
- }
-}
-
-static int
-detach_callback (struct lwp_info *lp, void *data)
-{
- gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
-
- if (debug_lin_lwp && lp->status)
- fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
- strsignal (WSTOPSIG (lp->status)),
- target_pid_to_str (lp->ptid));
-
- while (lp->signalled && lp->stopped)
- {
- errno = 0;
- if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0,
- WSTOPSIG (lp->status)) < 0)
- error ("Can't continue %s: %s", target_pid_to_str (lp->ptid),
- safe_strerror (errno));
-
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n",
- target_pid_to_str (lp->ptid),
- status_to_str (lp->status));
-
- lp->stopped = 0;
- lp->signalled = 0;
- lp->status = 0;
- /* FIXME drow/2003-08-26: There was a call to stop_wait_callback
- here. But since lp->signalled was cleared above,
- stop_wait_callback didn't do anything; the process was left
- running. Shouldn't we be waiting for it to stop?
- I've removed the call, since stop_wait_callback now does do
- something when called with lp->signalled == 0. */
-
- gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
- }
-
- /* We don't actually detach from the LWP that has an id equal to the
- overall process id just yet. */
- if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
- {
- errno = 0;
- if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
- WSTOPSIG (lp->status)) < 0)
- error ("Can't detach %s: %s", target_pid_to_str (lp->ptid),
- safe_strerror (errno));
-
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "PTRACE_DETACH (%s, %s, 0) (OK)\n",
- target_pid_to_str (lp->ptid),
- strsignal (WSTOPSIG (lp->status)));
-
- delete_lwp (lp->ptid);
- }
-
- return 0;
-}
-
-static void
-lin_lwp_detach (char *args, int from_tty)
-{
- iterate_over_lwps (detach_callback, NULL);
-
- /* Only the initial process should be left right now. */
- gdb_assert (num_lwps == 1);
-
- trap_ptid = null_ptid;
-
- /* Destroy LWP info; it's no longer valid. */
- init_lwp_list ();
-
- /* Restore the original signal mask. */
- sigprocmask (SIG_SETMASK, &normal_mask, NULL);
- sigemptyset (&blocked_mask);
-
- inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid));
- child_ops.to_detach (args, from_tty);
-}
-\f
-
-/* Resume LP. */
-
-static int
-resume_callback (struct lwp_info *lp, void *data)
-{
- if (lp->stopped && lp->status == 0)
- {
- struct thread_info *tp;
-
- child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n",
- target_pid_to_str (lp->ptid));
- lp->stopped = 0;
- lp->step = 0;
- }
-
- return 0;
-}
-
-static int
-resume_clear_callback (struct lwp_info *lp, void *data)
-{
- lp->resumed = 0;
- return 0;
-}
-
-static int
-resume_set_callback (struct lwp_info *lp, void *data)
-{
- lp->resumed = 1;
- return 0;
-}
-
-static void
-lin_lwp_resume (ptid_t ptid, int step, enum target_signal signo)
-{
- struct lwp_info *lp;
- int resume_all;
-
- /* A specific PTID means `step only this process id'. */
- resume_all = (PIDGET (ptid) == -1);
-
- if (resume_all)
- iterate_over_lwps (resume_set_callback, NULL);
- else
- iterate_over_lwps (resume_clear_callback, NULL);
-
- /* If PID is -1, it's the current inferior that should be
- handled specially. */
- if (PIDGET (ptid) == -1)
- ptid = inferior_ptid;
-
- lp = find_lwp_pid (ptid);
- if (lp)
- {
- ptid = pid_to_ptid (GET_LWP (lp->ptid));
-
- /* Remember if we're stepping. */
- lp->step = step;
-
- /* Mark this LWP as resumed. */
- lp->resumed = 1;
-
- /* If we have a pending wait status for this thread, there is no
- point in resuming the process. */
- if (lp->status)
- {
- /* FIXME: What should we do if we are supposed to continue
- this thread with a signal? */
- gdb_assert (signo == TARGET_SIGNAL_0);
- return;
- }
-
- /* Mark LWP as not stopped to prevent it from being continued by
- resume_callback. */
- lp->stopped = 0;
- }
-
- if (resume_all)
- iterate_over_lwps (resume_callback, NULL);
-
- child_resume (ptid, step, signo);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLR: %s %s, %s (resume event thread)\n",
- step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
- target_pid_to_str (ptid),
- signo ? strsignal (signo) : "0");
-}
-\f
-
-/* Issue kill to specified lwp. */
-
-static int tkill_failed;
-
-static int
-kill_lwp (int lwpid, int signo)
-{
- errno = 0;
-
-/* Use tkill, if possible, in case we are using nptl threads. If tkill
- fails, then we are not using nptl threads and we should be using kill. */
-
-#ifdef HAVE_TKILL_SYSCALL
- if (!tkill_failed)
- {
- int ret = syscall (__NR_tkill, lwpid, signo);
- if (errno != ENOSYS)
- return ret;
- errno = 0;
- tkill_failed = 1;
- }
-#endif
-
- return kill (lwpid, signo);
-}
-
-/* Handle a GNU/Linux extended wait response. Most of the work we
- just pass off to linux_handle_extended_wait, but if it reports a
- clone event we need to add the new LWP to our list (and not report
- the trap to higher layers). This function returns non-zero if
- the event should be ignored and we should wait again. */
-
-static int
-lin_lwp_handle_extended (struct lwp_info *lp, int status)
-{
- linux_handle_extended_wait (GET_LWP (lp->ptid), status,
- &lp->waitstatus);
-
- /* TARGET_WAITKIND_SPURIOUS is used to indicate clone events. */
- if (lp->waitstatus.kind == TARGET_WAITKIND_SPURIOUS)
- {
- struct lwp_info *new_lp;
- new_lp = add_lwp (BUILD_LWP (lp->waitstatus.value.related_pid,
- GET_PID (inferior_ptid)));
- new_lp->cloned = 1;
- new_lp->stopped = 1;
-
- lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
-
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLHE: Got clone event from LWP %ld, resuming\n",
- GET_LWP (lp->ptid));
- ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
-
- return 1;
- }
-
- return 0;
-}
-
-/* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
- exited. */
-
-static int
-wait_lwp (struct lwp_info *lp)
-{
- pid_t pid;
- int status;
- int thread_dead = 0;
-
- gdb_assert (!lp->stopped);
- gdb_assert (lp->status == 0);
-
- pid = waitpid (GET_LWP (lp->ptid), &status, 0);
- if (pid == -1 && errno == ECHILD)
- {
- pid = waitpid (GET_LWP (lp->ptid), &status, __WCLONE);
- if (pid == -1 && errno == ECHILD)
- {
- /* The thread has previously exited. We need to delete it
- now because, for some vendor 2.4 kernels with NPTL
- support backported, there won't be an exit event unless
- it is the main thread. 2.6 kernels will report an exit
- event for each thread that exits, as expected. */
- thread_dead = 1;
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
- target_pid_to_str (lp->ptid));
- }
- }
-
- if (!thread_dead)
- {
- gdb_assert (pid == GET_LWP (lp->ptid));
-
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "WL: waitpid %s received %s\n",
- target_pid_to_str (lp->ptid),
- status_to_str (status));
- }
- }
-
- /* Check if the thread has exited. */
- if (WIFEXITED (status) || WIFSIGNALED (status))
- {
- thread_dead = 1;
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
- target_pid_to_str (lp->ptid));
- }
-
- if (thread_dead)
- {
- if (in_thread_list (lp->ptid))
- {
- /* Core GDB cannot deal with us deleting the current thread. */
- if (!ptid_equal (lp->ptid, inferior_ptid))
- delete_thread (lp->ptid);
- printf_unfiltered ("[%s exited]\n",
- target_pid_to_str (lp->ptid));
- }
-
- delete_lwp (lp->ptid);
- return 0;
- }
-
- gdb_assert (WIFSTOPPED (status));
-
- /* Handle GNU/Linux's extended waitstatus for trace events. */
- if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
- {
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "WL: Handling extended status 0x%06x\n",
- status);
- if (lin_lwp_handle_extended (lp, status))
- return wait_lwp (lp);
- }
-
- return status;
-}
-
-/* Send a SIGSTOP to LP. */
-
-static int
-stop_callback (struct lwp_info *lp, void *data)
-{
- if (!lp->stopped && !lp->signalled)
- {
- int ret;
-
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "SC: kill %s **<SIGSTOP>**\n",
- target_pid_to_str (lp->ptid));
- }
- errno = 0;
- ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP);
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "SC: lwp kill %d %s\n",
- ret,
- errno ? safe_strerror (errno) : "ERRNO-OK");
- }
-
- lp->signalled = 1;
- gdb_assert (lp->status == 0);
- }
-
- return 0;
-}
-
-/* Wait until LP is stopped. If DATA is non-null it is interpreted as
- a pointer to a set of signals to be flushed immediately. */
-
-static int
-stop_wait_callback (struct lwp_info *lp, void *data)
-{
- sigset_t *flush_mask = data;
-
- if (!lp->stopped)
- {
- int status;
-
- status = wait_lwp (lp);
- if (status == 0)
- return 0;
-
- /* Ignore any signals in FLUSH_MASK. */
- if (flush_mask && sigismember (flush_mask, WSTOPSIG (status)))
- {
- if (!lp->signalled)
- {
- lp->stopped = 1;
- return 0;
- }
-
- errno = 0;
- ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "PTRACE_CONT %s, 0, 0 (%s)\n",
- target_pid_to_str (lp->ptid),
- errno ? safe_strerror (errno) : "OK");
-
- return stop_wait_callback (lp, flush_mask);
- }
-
- if (WSTOPSIG (status) != SIGSTOP)
- {
- if (WSTOPSIG (status) == SIGTRAP)
- {
- /* If a LWP other than the LWP that we're reporting an
- event for has hit a GDB breakpoint (as opposed to
- some random trap signal), then just arrange for it to
- hit it again later. We don't keep the SIGTRAP status
- and don't forward the SIGTRAP signal to the LWP. We
- will handle the current event, eventually we will
- resume all LWPs, and this one will get its breakpoint
- trap again.
-
- If we do not do this, then we run the risk that the
- user will delete or disable the breakpoint, but the
- thread will have already tripped on it. */
-
- /* Now resume this LWP and get the SIGSTOP event. */
- errno = 0;
- ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "PTRACE_CONT %s, 0, 0 (%s)\n",
- target_pid_to_str (lp->ptid),
- errno ? safe_strerror (errno) : "OK");
-
- fprintf_unfiltered (gdb_stdlog,
- "SWC: Candidate SIGTRAP event in %s\n",
- target_pid_to_str (lp->ptid));
- }
- /* Hold the SIGTRAP for handling by lin_lwp_wait. */
- stop_wait_callback (lp, data);
- /* If there's another event, throw it back into the queue. */
- if (lp->status)
- {
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "SWC: kill %s, %s\n",
- target_pid_to_str (lp->ptid),
- status_to_str ((int) status));
- }
- kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
- }
- /* Save the sigtrap event. */
- lp->status = status;
- return 0;
- }
- else
- {
- /* The thread was stopped with a signal other than
- SIGSTOP, and didn't accidentally trip a breakpoint. */
-
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "SWC: Pending event %s in %s\n",
- status_to_str ((int) status),
- target_pid_to_str (lp->ptid));
- }
- /* Now resume this LWP and get the SIGSTOP event. */
- errno = 0;
- ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "SWC: PTRACE_CONT %s, 0, 0 (%s)\n",
- target_pid_to_str (lp->ptid),
- errno ? safe_strerror (errno) : "OK");
-
- /* Hold this event/waitstatus while we check to see if
- there are any more (we still want to get that SIGSTOP). */
- stop_wait_callback (lp, data);
- /* If the lp->status field is still empty, use it to hold
- this event. If not, then this event must be returned
- to the event queue of the LWP. */
- if (lp->status == 0)
- lp->status = status;
- else
- {
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "SWC: kill %s, %s\n",
- target_pid_to_str (lp->ptid),
- status_to_str ((int) status));
- }
- kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status));
- }
- return 0;
- }
- }
- else
- {
- /* We caught the SIGSTOP that we intended to catch, so
- there's no SIGSTOP pending. */
- lp->stopped = 1;
- lp->signalled = 0;
- }
- }
-
- return 0;
-}
-
-/* Check whether PID has any pending signals in FLUSH_MASK. If so set
- the appropriate bits in PENDING, and return 1 - otherwise return 0. */
-
-static int
-lin_lwp_has_pending (int pid, sigset_t *pending, sigset_t *flush_mask)
-{
- sigset_t blocked, ignored;
- int i;
-
- linux_proc_pending_signals (pid, pending, &blocked, &ignored);
-
- if (!flush_mask)
- return 0;
-
- for (i = 1; i < NSIG; i++)
- if (sigismember (pending, i))
- if (!sigismember (flush_mask, i)
- || sigismember (&blocked, i)
- || sigismember (&ignored, i))
- sigdelset (pending, i);
-
- if (sigisemptyset (pending))
- return 0;
-
- return 1;
-}
-
-/* DATA is interpreted as a mask of signals to flush. If LP has
- signals pending, and they are all in the flush mask, then arrange
- to flush them. LP should be stopped, as should all other threads
- it might share a signal queue with. */
-
-static int
-flush_callback (struct lwp_info *lp, void *data)
-{
- sigset_t *flush_mask = data;
- sigset_t pending, intersection, blocked, ignored;
- int pid, status;
-
- /* Normally, when an LWP exits, it is removed from the LWP list. The
- last LWP isn't removed till later, however. So if there is only
- one LWP on the list, make sure it's alive. */
- if (lwp_list == lp && lp->next == NULL)
- if (!lin_lwp_thread_alive (lp->ptid))
- return 0;
-
- /* Just because the LWP is stopped doesn't mean that new signals
- can't arrive from outside, so this function must be careful of
- race conditions. However, because all threads are stopped, we
- can assume that the pending mask will not shrink unless we resume
- the LWP, and that it will then get another signal. We can't
- control which one, however. */
-
- if (lp->status)
- {
- if (debug_lin_lwp)
- printf_unfiltered ("FC: LP has pending status %06x\n", lp->status);
- if (WIFSTOPPED (lp->status) && sigismember (flush_mask, WSTOPSIG (lp->status)))
- lp->status = 0;
- }
-
- while (lin_lwp_has_pending (GET_LWP (lp->ptid), &pending, flush_mask))
- {
- int ret;
-
- errno = 0;
- ret = ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stderr,
- "FC: Sent PTRACE_CONT, ret %d %d\n", ret, errno);
-
- lp->stopped = 0;
- stop_wait_callback (lp, flush_mask);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stderr,
- "FC: Wait finished; saved status is %d\n",
- lp->status);
- }
-
- return 0;
-}
-
-/* Return non-zero if LP has a wait status pending. */
-
-static int
-status_callback (struct lwp_info *lp, void *data)
-{
- /* Only report a pending wait status if we pretend that this has
- indeed been resumed. */
- return (lp->status != 0 && lp->resumed);
-}
-
-/* Return non-zero if LP isn't stopped. */
-
-static int
-running_callback (struct lwp_info *lp, void *data)
-{
- return (lp->stopped == 0 || (lp->status != 0 && lp->resumed));
-}
-
-/* Count the LWP's that have had events. */
-
-static int
-count_events_callback (struct lwp_info *lp, void *data)
-{
- int *count = data;
-
- gdb_assert (count != NULL);
-
- /* Count only LWPs that have a SIGTRAP event pending. */
- if (lp->status != 0
- && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
- (*count)++;
-
- return 0;
-}
-
-/* Select the LWP (if any) that is currently being single-stepped. */
-
-static int
-select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
-{
- if (lp->step && lp->status != 0)
- return 1;
- else
- return 0;
-}
-
-/* Select the Nth LWP that has had a SIGTRAP event. */
-
-static int
-select_event_lwp_callback (struct lwp_info *lp, void *data)
-{
- int *selector = data;
-
- gdb_assert (selector != NULL);
-
- /* Select only LWPs that have a SIGTRAP event pending. */
- if (lp->status != 0
- && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
- if ((*selector)-- == 0)
- return 1;
-
- return 0;
-}
-
-static int
-cancel_breakpoints_callback (struct lwp_info *lp, void *data)
-{
- struct lwp_info *event_lp = data;
-
- /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
- if (lp == event_lp)
- return 0;
-
- /* If a LWP other than the LWP that we're reporting an event for has
- hit a GDB breakpoint (as opposed to some random trap signal),
- then just arrange for it to hit it again later. We don't keep
- the SIGTRAP status and don't forward the SIGTRAP signal to the
- LWP. We will handle the current event, eventually we will resume
- all LWPs, and this one will get its breakpoint trap again.
-
- If we do not do this, then we run the risk that the user will
- delete or disable the breakpoint, but the LWP will have already
- tripped on it. */
-
- if (lp->status != 0
- && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP
- && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) -
- DECR_PC_AFTER_BREAK))
- {
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "CBC: Push back breakpoint for %s\n",
- target_pid_to_str (lp->ptid));
-
- /* Back up the PC if necessary. */
- if (DECR_PC_AFTER_BREAK)
- write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid);
-
- /* Throw away the SIGTRAP. */
- lp->status = 0;
- }
-
- return 0;
-}
-
-/* Select one LWP out of those that have events pending. */
-
-static void
-select_event_lwp (struct lwp_info **orig_lp, int *status)
-{
- int num_events = 0;
- int random_selector;
- struct lwp_info *event_lp;
-
- /* Record the wait status for the origional LWP. */
- (*orig_lp)->status = *status;
-
- /* Give preference to any LWP that is being single-stepped. */
- event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL);
- if (event_lp != NULL)
- {
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "SEL: Select single-step %s\n",
- target_pid_to_str (event_lp->ptid));
- }
- else
- {
- /* No single-stepping LWP. Select one at random, out of those
- which have had SIGTRAP events. */
-
- /* First see how many SIGTRAP events we have. */
- iterate_over_lwps (count_events_callback, &num_events);
-
- /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
- random_selector = (int)
- ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
-
- if (debug_lin_lwp && num_events > 1)
- fprintf_unfiltered (gdb_stdlog,
- "SEL: Found %d SIGTRAP events, selecting #%d\n",
- num_events, random_selector);
-
- event_lp = iterate_over_lwps (select_event_lwp_callback,
- &random_selector);
- }
-
- if (event_lp != NULL)
- {
- /* Switch the event LWP. */
- *orig_lp = event_lp;
- *status = event_lp->status;
- }
-
- /* Flush the wait status for the event LWP. */
- (*orig_lp)->status = 0;
-}
-
-/* Return non-zero if LP has been resumed. */
-
-static int
-resumed_callback (struct lwp_info *lp, void *data)
-{
- return lp->resumed;
-}
-
-#ifdef CHILD_WAIT
-
-/* We need to override child_wait to support attaching to cloned
- processes, since a normal wait (as done by the default version)
- ignores those processes. */
-
-/* Wait for child PTID to do something. Return id of the child,
- minus_one_ptid in case of error; store status into *OURSTATUS. */
-
-ptid_t
-child_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
-{
- int save_errno;
- int status;
- pid_t pid;
-
- ourstatus->kind = TARGET_WAITKIND_IGNORE;
-
- do
- {
- set_sigint_trap (); /* Causes SIGINT to be passed on to the
- attached process. */
- set_sigio_trap ();
-
- pid = waitpid (GET_PID (ptid), &status, 0);
- if (pid == -1 && errno == ECHILD)
- /* Try again with __WCLONE to check cloned processes. */
- pid = waitpid (GET_PID (ptid), &status, __WCLONE);
-
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "CW: waitpid %ld received %s\n",
- (long) pid, status_to_str (status));
- }
-
- save_errno = errno;
-
- /* Make sure we don't report an event for the exit of the
- original program, if we've detached from it. */
- if (pid != -1 && !WIFSTOPPED (status) && pid != GET_PID (inferior_ptid))
- {
- pid = -1;
- save_errno = EINTR;
- }
-
- /* Check for stop events reported by a process we didn't already
- know about - in this case, anything other than inferior_ptid.
-
- 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. If we want to handle debugging of
- CLONE_PTRACE processes we need to do more here, i.e. switch
- to multi-threaded mode. */
- if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP
- && pid != GET_PID (inferior_ptid))
- {
- linux_record_stopped_pid (pid);
- pid = -1;
- save_errno = EINTR;
- }
-
- /* Handle GNU/Linux's extended waitstatus for trace events. */
- if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
- && status >> 16 != 0)
- {
- linux_handle_extended_wait (pid, status, ourstatus);
-
- /* If we see a clone event, detach the child, and don't
- report the event. It would be nice to offer some way to
- switch into a non-thread-db based threaded mode at this
- point. */
- if (ourstatus->kind == TARGET_WAITKIND_SPURIOUS)
- {
- ptrace (PTRACE_DETACH, ourstatus->value.related_pid, 0, 0);
- ourstatus->kind = TARGET_WAITKIND_IGNORE;
- ptrace (PTRACE_CONT, pid, 0, 0);
- pid = -1;
- save_errno = EINTR;
- }
- }
-
- clear_sigio_trap ();
- clear_sigint_trap ();
- }
- while (pid == -1 && save_errno == EINTR);
-
- if (pid == -1)
- {
- warning ("Child process unexpectedly missing: %s",
- safe_strerror (errno));
-
- /* Claim it exited with unknown signal. */
- ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
- ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
- return minus_one_ptid;
- }
-
- if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
- store_waitstatus (ourstatus, status);
-
- return pid_to_ptid (pid);
-}
-
-#endif
-
-/* Stop an active thread, verify it still exists, then resume it. */
-
-static int
-stop_and_resume_callback (struct lwp_info *lp, void *data)
-{
- struct lwp_info *ptr;
-
- if (!lp->stopped && !lp->signalled)
- {
- stop_callback (lp, NULL);
- stop_wait_callback (lp, NULL);
- /* Resume if the lwp still exists. */
- for (ptr = lwp_list; ptr; ptr = ptr->next)
- if (lp == ptr)
- {
- resume_callback (lp, NULL);
- resume_set_callback (lp, NULL);
- }
- }
- return 0;
-}
-
-static ptid_t
-lin_lwp_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
-{
- struct lwp_info *lp = NULL;
- int options = 0;
- int status = 0;
- pid_t pid = PIDGET (ptid);
- sigset_t flush_mask;
-
- sigemptyset (&flush_mask);
-
- /* Make sure SIGCHLD is blocked. */
- if (!sigismember (&blocked_mask, SIGCHLD))
- {
- sigaddset (&blocked_mask, SIGCHLD);
- sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
- }
-
-retry:
-
- /* Make sure there is at least one LWP that has been resumed, at
- least if there are any LWPs at all. */
- gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL));
-
- /* First check if there is a LWP with a wait status pending. */
- if (pid == -1)
- {
- /* Any LWP that's been resumed will do. */
- lp = iterate_over_lwps (status_callback, NULL);
- if (lp)
- {
- status = lp->status;
- lp->status = 0;
-
- if (debug_lin_lwp && status)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: Using pending wait status %s for %s.\n",
- status_to_str (status),
- target_pid_to_str (lp->ptid));
- }
-
- /* But if we don't fine one, we'll have to wait, and check both
- cloned and uncloned processes. We start with the cloned
- processes. */
- options = __WCLONE | WNOHANG;
- }
- else if (is_lwp (ptid))
- {
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: Waiting for specific LWP %s.\n",
- target_pid_to_str (ptid));
-
- /* We have a specific LWP to check. */
- lp = find_lwp_pid (ptid);
- gdb_assert (lp);
- status = lp->status;
- lp->status = 0;
-
- if (debug_lin_lwp && status)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: Using pending wait status %s for %s.\n",
- status_to_str (status),
- target_pid_to_str (lp->ptid));
-
- /* If we have to wait, take into account whether PID is a cloned
- process or not. And we have to convert it to something that
- the layer beneath us can understand. */
- options = lp->cloned ? __WCLONE : 0;
- pid = GET_LWP (ptid);
- }
-
- if (status && lp->signalled)
- {
- /* A pending SIGSTOP may interfere with the normal stream of
- events. In a typical case where interference is a problem,
- we have a SIGSTOP signal pending for LWP A while
- single-stepping it, encounter an event in LWP B, and take the
- pending SIGSTOP while trying to stop LWP A. After processing
- the event in LWP B, LWP A is continued, and we'll never see
- the SIGTRAP associated with the last time we were
- single-stepping LWP A. */
-
- /* Resume the thread. It should halt immediately returning the
- pending SIGSTOP. */
- registers_changed ();
- child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
- TARGET_SIGNAL_0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: %s %s, 0, 0 (expect SIGSTOP)\n",
- lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
- target_pid_to_str (lp->ptid));
- lp->stopped = 0;
- gdb_assert (lp->resumed);
-
- /* This should catch the pending SIGSTOP. */
- stop_wait_callback (lp, NULL);
- }
-
- set_sigint_trap (); /* Causes SIGINT to be passed on to the
- attached process. */
- set_sigio_trap ();
-
- while (status == 0)
- {
- pid_t lwpid;
-
- lwpid = waitpid (pid, &status, options);
- if (lwpid > 0)
- {
- gdb_assert (pid == -1 || lwpid == pid);
-
- if (debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "LLW: waitpid %ld received %s\n",
- (long) lwpid, status_to_str (status));
- }
-
- lp = find_lwp_pid (pid_to_ptid (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. */
- if (WIFSTOPPED (status) && !lp)
- {
- linux_record_stopped_pid (lwpid);
- status = 0;
- continue;
- }
-
- /* Make sure we don't report an event for the exit of an LWP not in
- our list, i.e. not part of the current process. This can happen
- if we detach from a program we original forked and then it
- exits. */
- if (!WIFSTOPPED (status) && !lp)
- {
- status = 0;
- continue;
- }
-
- /* NOTE drow/2003-06-17: This code seems to be meant for debugging
- CLONE_PTRACE processes which do not use the thread library -
- otherwise we wouldn't find the new LWP this way. That doesn't
- currently work, and the following code is currently unreachable
- due to the two blocks above. If it's fixed some day, this code
- should be broken out into a function so that we can also pick up
- LWPs from the new interface. */
- if (!lp)
- {
- lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));
- if (options & __WCLONE)
- lp->cloned = 1;
-
- if (threaded)
- {
- gdb_assert (WIFSTOPPED (status)
- && WSTOPSIG (status) == SIGSTOP);
- lp->signalled = 1;
-
- if (!in_thread_list (inferior_ptid))
- {
- inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid),
- GET_PID (inferior_ptid));
- add_thread (inferior_ptid);
- }
-
- add_thread (lp->ptid);
- printf_unfiltered ("[New %s]\n",
- target_pid_to_str (lp->ptid));
- }
- }
-
- /* Handle GNU/Linux's extended waitstatus for trace events. */
- if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
- {
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: Handling extended status 0x%06x\n",
- status);
- if (lin_lwp_handle_extended (lp, status))
- {
- status = 0;
- continue;
- }
- }
-
- /* Check if the thread has exited. */
- if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1)
- {
- if (in_thread_list (lp->ptid))
- {
- /* Core GDB cannot deal with us deleting the current
- thread. */
- if (!ptid_equal (lp->ptid, inferior_ptid))
- delete_thread (lp->ptid);
- printf_unfiltered ("[%s exited]\n",
- target_pid_to_str (lp->ptid));
- }
-
- /* If this is the main thread, we must stop all threads and
- verify if they are still alive. This is because in the nptl
- thread model, there is no signal issued for exiting LWPs
- other than the main thread. We only get the main thread
- exit signal once all child threads have already exited.
- If we stop all the threads and use the stop_wait_callback
- to check if they have exited we can determine whether this
- signal should be ignored or whether it means the end of the
- debugged application, regardless of which threading model
- is being used. */
- if (GET_PID (lp->ptid) == GET_LWP (lp->ptid))
- {
- lp->stopped = 1;
- iterate_over_lwps (stop_and_resume_callback, NULL);
- }
-
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: %s exited.\n",
- target_pid_to_str (lp->ptid));
-
- delete_lwp (lp->ptid);
-
- /* If there is at least one more LWP, then the exit signal
- was not the end of the debugged application and should be
- ignored. */
- if (num_lwps > 0)
- {
- /* Make sure there is at least one thread running. */
- gdb_assert (iterate_over_lwps (running_callback, NULL));
-
- /* Discard the event. */
- status = 0;
- continue;
- }
- }
-
- /* Check if the current LWP has previously exited. In the nptl
- thread model, LWPs other than the main thread do not issue
- signals when they exit so we must check whenever the thread
- has stopped. A similar check is made in stop_wait_callback(). */
- if (num_lwps > 1 && !lin_lwp_thread_alive (lp->ptid))
- {
- if (in_thread_list (lp->ptid))
- {
- /* Core GDB cannot deal with us deleting the current
- thread. */
- if (!ptid_equal (lp->ptid, inferior_ptid))
- delete_thread (lp->ptid);
- printf_unfiltered ("[%s exited]\n",
- target_pid_to_str (lp->ptid));
- }
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: %s exited.\n",
- target_pid_to_str (lp->ptid));
-
- delete_lwp (lp->ptid);
-
- /* Make sure there is at least one thread running. */
- gdb_assert (iterate_over_lwps (running_callback, NULL));
-
- /* Discard the event. */
- status = 0;
- continue;
- }
-
- /* Make sure we don't report a SIGSTOP that we sent
- ourselves in an attempt to stop an LWP. */
- if (lp->signalled
- && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
- {
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: Delayed SIGSTOP caught for %s.\n",
- target_pid_to_str (lp->ptid));
-
- /* This is a delayed SIGSTOP. */
- lp->signalled = 0;
-
- registers_changed ();
- child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
- TARGET_SIGNAL_0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
- lp->step ?
- "PTRACE_SINGLESTEP" : "PTRACE_CONT",
- target_pid_to_str (lp->ptid));
-
- lp->stopped = 0;
- gdb_assert (lp->resumed);
-
- /* Discard the event. */
- status = 0;
- continue;
- }
-
- break;
- }
-
- if (pid == -1)
- {
- /* Alternate between checking cloned and uncloned processes. */
- options ^= __WCLONE;
-
- /* And suspend every time we have checked both. */
- if (options & __WCLONE)
- sigsuspend (&suspend_mask);
- }
-
- /* We shouldn't end up here unless we want to try again. */
- gdb_assert (status == 0);
- }
-
- clear_sigio_trap ();
- clear_sigint_trap ();
-
- gdb_assert (lp);
-
- /* Don't report signals that GDB isn't interested in, such as
- signals that are neither printed nor stopped upon. Stopping all
- threads can be a bit time-consuming so if we want decent
- performance with heavily multi-threaded programs, especially when
- they're using a high frequency timer, we'd better avoid it if we
- can. */
-
- if (WIFSTOPPED (status))
- {
- int signo = target_signal_from_host (WSTOPSIG (status));
-
- if (signal_stop_state (signo) == 0
- && signal_print_state (signo) == 0
- && signal_pass_state (signo) == 1)
- {
- /* FIMXE: kettenis/2001-06-06: Should we resume all threads
- here? It is not clear we should. GDB may not expect
- other threads to run. On the other hand, not resuming
- newly attached threads may cause an unwanted delay in
- getting them running. */
- registers_changed ();
- child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: %s %s, %s (preempt 'handle')\n",
- lp->step ?
- "PTRACE_SINGLESTEP" : "PTRACE_CONT",
- target_pid_to_str (lp->ptid),
- signo ? strsignal (signo) : "0");
- lp->stopped = 0;
- status = 0;
- goto retry;
- }
-
- if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0)
- {
- /* If ^C/BREAK is typed at the tty/console, SIGINT gets
- forwarded to the entire process group, that is, all LWP's
- will receive it. Since we only want to report it once,
- we try to flush it from all LWPs except this one. */
- sigaddset (&flush_mask, SIGINT);
- }
- }
-
- /* This LWP is stopped now. */
- lp->stopped = 1;
-
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
- status_to_str (status), target_pid_to_str (lp->ptid));
-
- /* Now stop all other LWP's ... */
- iterate_over_lwps (stop_callback, NULL);
-
- /* ... and wait until all of them have reported back that they're no
- longer running. */
- iterate_over_lwps (stop_wait_callback, &flush_mask);
- iterate_over_lwps (flush_callback, &flush_mask);
-
- /* 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 (pid == -1)
- select_event_lwp (&lp, &status);
-
- /* Now that we've selected our final event LWP, cancel any
- breakpoints in other LWPs that have hit a GDB breakpoint. See
- the comment in cancel_breakpoints_callback to find out why. */
- iterate_over_lwps (cancel_breakpoints_callback, lp);
-
- /* If we're not running in "threaded" mode, we'll report the bare
- process id. */
-
- if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP)
- {
- trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLW: trap_ptid is %s.\n",
- target_pid_to_str (trap_ptid));
- }
- else
- trap_ptid = null_ptid;
-
- if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
- {
- *ourstatus = lp->waitstatus;
- lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
- }
- else
- store_waitstatus (ourstatus, status);
-
- return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
-}
-
-static int
-kill_callback (struct lwp_info *lp, void *data)
-{
- errno = 0;
- ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
- target_pid_to_str (lp->ptid),
- errno ? safe_strerror (errno) : "OK");
-
- return 0;
-}
-
-static int
-kill_wait_callback (struct lwp_info *lp, void *data)
-{
- pid_t pid;
-
- /* We must make sure that there are no pending events (delayed
- SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
- program doesn't interfere with any following debugging session. */
-
- /* For cloned processes we must check both with __WCLONE and
- without, since the exit status of a cloned process isn't reported
- with __WCLONE. */
- if (lp->cloned)
- {
- do
- {
- pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE);
- if (pid != (pid_t) -1 && debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "KWC: wait %s received unknown.\n",
- target_pid_to_str (lp->ptid));
- }
- }
- while (pid == GET_LWP (lp->ptid));
-
- gdb_assert (pid == -1 && errno == ECHILD);
- }
-
- do
- {
- pid = waitpid (GET_LWP (lp->ptid), NULL, 0);
- if (pid != (pid_t) -1 && debug_lin_lwp)
- {
- fprintf_unfiltered (gdb_stdlog,
- "KWC: wait %s received unk.\n",
- target_pid_to_str (lp->ptid));
- }
- }
- while (pid == GET_LWP (lp->ptid));
-
- gdb_assert (pid == -1 && errno == ECHILD);
- return 0;
-}
-
-static void
-lin_lwp_kill (void)
-{
- /* Kill all LWP's ... */
- iterate_over_lwps (kill_callback, NULL);
-
- /* ... and wait until we've flushed all events. */
- iterate_over_lwps (kill_wait_callback, NULL);
-
- target_mourn_inferior ();
-}
-
-static void
-lin_lwp_create_inferior (char *exec_file, char *allargs, char **env,
- int from_tty)
-{
- child_ops.to_create_inferior (exec_file, allargs, env, from_tty);
-}
-
-static void
-lin_lwp_mourn_inferior (void)
-{
- trap_ptid = null_ptid;
-
- /* Destroy LWP info; it's no longer valid. */
- init_lwp_list ();
-
- /* Restore the original signal mask. */
- sigprocmask (SIG_SETMASK, &normal_mask, NULL);
- sigemptyset (&blocked_mask);
-
- child_ops.to_mourn_inferior ();
-}
-
-static int
-lin_lwp_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
- struct mem_attrib *attrib, struct target_ops *target)
-{
- struct cleanup *old_chain = save_inferior_ptid ();
- int xfer;
-
- if (is_lwp (inferior_ptid))
- inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
-
- xfer = linux_proc_xfer_memory (memaddr, myaddr, len, write, attrib, target);
- if (xfer == 0)
- xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target);
-
- do_cleanups (old_chain);
- return xfer;
-}
-
-static int
-lin_lwp_thread_alive (ptid_t ptid)
-{
- gdb_assert (is_lwp (ptid));
-
- errno = 0;
- ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0);
- if (debug_lin_lwp)
- fprintf_unfiltered (gdb_stdlog,
- "LLTA: PTRACE_PEEKUSER %s, 0, 0 (%s)\n",
- target_pid_to_str (ptid),
- errno ? safe_strerror (errno) : "OK");
- if (errno)
- return 0;
-
- return 1;
-}
-
-static char *
-lin_lwp_pid_to_str (ptid_t ptid)
-{
- static char buf[64];
-
- if (is_lwp (ptid))
- {
- snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid));
- return buf;
- }
-
- return normal_pid_to_str (ptid);
-}
-
-static void
-init_lin_lwp_ops (void)
-{
-#if 0
- lin_lwp_ops.to_open = lin_lwp_open;
-#endif
- lin_lwp_ops.to_shortname = "lwp-layer";
- lin_lwp_ops.to_longname = "lwp-layer";
- lin_lwp_ops.to_doc = "Low level threads support (LWP layer)";
- lin_lwp_ops.to_attach = lin_lwp_attach;
- lin_lwp_ops.to_detach = lin_lwp_detach;
- lin_lwp_ops.to_resume = lin_lwp_resume;
- lin_lwp_ops.to_wait = lin_lwp_wait;
- /* fetch_inferior_registers and store_inferior_registers will
- honor the LWP id, so we can use them directly. */
- lin_lwp_ops.to_fetch_registers = fetch_inferior_registers;
- lin_lwp_ops.to_store_registers = store_inferior_registers;
- lin_lwp_ops.to_xfer_memory = lin_lwp_xfer_memory;
- lin_lwp_ops.to_kill = lin_lwp_kill;
- lin_lwp_ops.to_create_inferior = lin_lwp_create_inferior;
- lin_lwp_ops.to_mourn_inferior = lin_lwp_mourn_inferior;
- lin_lwp_ops.to_thread_alive = lin_lwp_thread_alive;
- lin_lwp_ops.to_pid_to_str = lin_lwp_pid_to_str;
- lin_lwp_ops.to_post_startup_inferior = child_post_startup_inferior;
- lin_lwp_ops.to_post_attach = child_post_attach;
- lin_lwp_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint;
- lin_lwp_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint;
- lin_lwp_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint;
-
- lin_lwp_ops.to_stratum = thread_stratum;
- lin_lwp_ops.to_has_thread_control = tc_schedlock;
- lin_lwp_ops.to_magic = OPS_MAGIC;
-}
-
-static void
-sigchld_handler (int signo)
-{
- /* Do nothing. The only reason for this handler is that it allows
- us to use sigsuspend in lin_lwp_wait above to wait for the
- arrival of a SIGCHLD. */
-}
-
-void
-_initialize_lin_lwp (void)
-{
- struct sigaction action;
-
- extern void thread_db_init (struct target_ops *);
-
- init_lin_lwp_ops ();
- add_target (&lin_lwp_ops);
- thread_db_init (&lin_lwp_ops);
-
- /* Save the original signal mask. */
- sigprocmask (SIG_SETMASK, NULL, &normal_mask);
-
- action.sa_handler = sigchld_handler;
- sigemptyset (&action.sa_mask);
- action.sa_flags = 0;
- sigaction (SIGCHLD, &action, NULL);
-
- /* Make sure we don't block SIGCHLD during a sigsuspend. */
- sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
- sigdelset (&suspend_mask, SIGCHLD);
-
- sigemptyset (&blocked_mask);
-
- deprecated_add_show_from_set
- (add_set_cmd ("lin-lwp", no_class, var_zinteger,
- (char *) &debug_lin_lwp,
- "Set debugging of GNU/Linux lwp module.\n\
-Enables printf debugging output.\n", &setdebuglist), &showdebuglist);
-}
-\f
-
-/* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
- the GNU/Linux Threads library and therefore doesn't really belong
- here. */
-
-/* Read variable NAME in the target and return its value if found.
- Otherwise return zero. It is assumed that the type of the variable
- is `int'. */
-
-static int
-get_signo (const char *name)
-{
- struct minimal_symbol *ms;
- int signo;
-
- ms = lookup_minimal_symbol (name, NULL, NULL);
- if (ms == NULL)
- return 0;
-
- if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (char *) &signo,
- sizeof (signo)) != 0)
- return 0;
-
- return signo;
-}
-
-/* Return the set of signals used by the threads library in *SET. */
-
-void
-lin_thread_get_thread_signals (sigset_t *set)
-{
- struct sigaction action;
- int restart, cancel;
-
- sigemptyset (set);
-
- restart = get_signo ("__pthread_sig_restart");
- if (restart == 0)
- return;
-
- cancel = get_signo ("__pthread_sig_cancel");
- if (cancel == 0)
- return;
-
- sigaddset (set, restart);
- sigaddset (set, cancel);
-
- /* The GNU/Linux Threads library makes terminating threads send a
- special "cancel" signal instead of SIGCHLD. Make sure we catch
- those (to prevent them from terminating GDB itself, which is
- likely to be their default action) and treat them the same way as
- SIGCHLD. */
-
- action.sa_handler = sigchld_handler;
- sigemptyset (&action.sa_mask);
- action.sa_flags = 0;
- sigaction (cancel, &action, NULL);
-
- /* We block the "cancel" signal throughout this code ... */
- sigaddset (&blocked_mask, cancel);
- sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
-
- /* ... except during a sigsuspend. */
- sigdelset (&suspend_mask, cancel);
-}
#include "defs.h"
#include "inferior.h"
#include "target.h"
-
+#include "gdb_string.h"
#include "gdb_wait.h"
+#include "gdb_assert.h"
+#ifdef HAVE_TKILL_SYSCALL
+#include <unistd.h>
+#include <sys/syscall.h>
+#endif
#include <sys/ptrace.h>
-
#include "linux-nat.h"
+#include "gdbthread.h"
+#include "gdbcmd.h"
+#include "regcache.h"
/* If the system headers did not provide the constants, hard-code the normal
values. */
#define __WALL 0x40000000 /* Wait for any child. */
#endif
+static int debug_linux_nat;
+
extern struct target_ops child_ops;
static int linux_parent_pid;
target_mourn_inferior ();
}
+
+/* On GNU/Linux there are no real LWP's. The closest thing to LWP's
+ are processes sharing the same VM space. A multi-threaded process
+ is basically a group of such processes. However, such a grouping
+ is almost entirely a user-space issue; the kernel doesn't enforce
+ such a grouping at all (this might change in the future). In
+ general, we'll rely on the threads library (i.e. the GNU/Linux
+ Threads library) to provide such a grouping.
+
+ It is perfectly well possible to write a multi-threaded application
+ without the assistance of a threads library, by using the clone
+ system call directly. This module should be able to give some
+ rudimentary support for debugging such applications if developers
+ specify the CLONE_PTRACE flag in the clone system call, and are
+ using the Linux kernel 2.4 or above.
+
+ Note that there are some peculiarities in GNU/Linux that affect
+ this code:
+
+ - In general one should specify the __WCLONE flag to waitpid in
+ order to make it report events for any of the cloned processes
+ (and leave it out for the initial process). However, if a cloned
+ process has exited the exit status is only reported if the
+ __WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
+ we cannot use it since GDB must work on older systems too.
+
+ - When a traced, cloned process exits and is waited for by the
+ debugger, the kernel reassigns it to the original parent and
+ keeps it around as a "zombie". Somehow, the GNU/Linux Threads
+ library doesn't notice this, which leads to the "zombie problem":
+ When debugged a multi-threaded process that spawns a lot of
+ threads will run out of processes, even if the threads exit,
+ because the "zombies" stay around. */
+
+/* List of known LWPs. */
+static struct lwp_info *lwp_list;
+
+/* Number of LWPs in the list. */
+static int num_lwps;
+
+/* Non-zero if we're running in "threaded" mode. */
+static int threaded;
+\f
+
+#define GET_LWP(ptid) ptid_get_lwp (ptid)
+#define GET_PID(ptid) ptid_get_pid (ptid)
+#define is_lwp(ptid) (GET_LWP (ptid) != 0)
+#define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0)
+
+/* If the last reported event was a SIGTRAP, this variable is set to
+ the process id of the LWP/thread that got it. */
+ptid_t trap_ptid;
+\f
+
+/* This module's target-specific operations. */
+static struct target_ops linux_nat_ops;
+
+/* The standard child operations. */
+extern struct target_ops child_ops;
+
+/* Since we cannot wait (in linux_nat_wait) for the initial process and
+ any cloned processes with a single call to waitpid, we have to use
+ the WNOHANG flag and call waitpid in a loop. To optimize
+ things a bit we use `sigsuspend' to wake us up when a process has
+ something to report (it will send us a SIGCHLD if it has). To make
+ this work we have to juggle with the signal mask. We save the
+ original signal mask such that we can restore it before creating a
+ new process in order to avoid blocking certain signals in the
+ inferior. We then block SIGCHLD during the waitpid/sigsuspend
+ loop. */
+
+/* Original signal mask. */
+static sigset_t normal_mask;
+
+/* Signal mask for use with sigsuspend in linux_nat_wait, initialized in
+ _initialize_linux_nat. */
+static sigset_t suspend_mask;
+
+/* Signals to block to make that sigsuspend work. */
+static sigset_t blocked_mask;
+\f
+
+/* Prototypes for local functions. */
+static int stop_wait_callback (struct lwp_info *lp, void *data);
+static int linux_nat_thread_alive (ptid_t ptid);
+\f
+/* Convert wait status STATUS to a string. Used for printing debug
+ messages only. */
+
+static char *
+status_to_str (int status)
+{
+ static char buf[64];
+
+ if (WIFSTOPPED (status))
+ snprintf (buf, sizeof (buf), "%s (stopped)",
+ strsignal (WSTOPSIG (status)));
+ else if (WIFSIGNALED (status))
+ snprintf (buf, sizeof (buf), "%s (terminated)",
+ strsignal (WSTOPSIG (status)));
+ else
+ snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
+
+ return buf;
+}
+
+/* Initialize the list of LWPs. Note that this module, contrary to
+ what GDB's generic threads layer does for its thread list,
+ re-initializes the LWP lists whenever we mourn or detach (which
+ doesn't involve mourning) the inferior. */
+
+static void
+init_lwp_list (void)
+{
+ struct lwp_info *lp, *lpnext;
+
+ for (lp = lwp_list; lp; lp = lpnext)
+ {
+ lpnext = lp->next;
+ xfree (lp);
+ }
+
+ lwp_list = NULL;
+ num_lwps = 0;
+ threaded = 0;
+}
+
+/* Add the LWP specified by PID to the list. If this causes the
+ number of LWPs to become larger than one, go into "threaded" mode.
+ Return a pointer to the structure describing the new LWP. */
+
+static struct lwp_info *
+add_lwp (ptid_t ptid)
+{
+ struct lwp_info *lp;
+
+ gdb_assert (is_lwp (ptid));
+
+ lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
+
+ memset (lp, 0, sizeof (struct lwp_info));
+
+ lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
+
+ lp->ptid = ptid;
+
+ lp->next = lwp_list;
+ lwp_list = lp;
+ if (++num_lwps > 1)
+ threaded = 1;
+
+ return lp;
+}
+
+/* Remove the LWP specified by PID from the list. */
+
+static void
+delete_lwp (ptid_t ptid)
+{
+ struct lwp_info *lp, *lpprev;
+
+ lpprev = NULL;
+
+ for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
+ if (ptid_equal (lp->ptid, ptid))
+ break;
+
+ if (!lp)
+ return;
+
+ /* We don't go back to "non-threaded" mode if the number of threads
+ becomes less than two. */
+ num_lwps--;
+
+ if (lpprev)
+ lpprev->next = lp->next;
+ else
+ lwp_list = lp->next;
+
+ xfree (lp);
+}
+
+/* Return a pointer to the structure describing the LWP corresponding
+ to PID. If no corresponding LWP could be found, return NULL. */
+
+static struct lwp_info *
+find_lwp_pid (ptid_t ptid)
+{
+ struct lwp_info *lp;
+ int lwp;
+
+ if (is_lwp (ptid))
+ lwp = GET_LWP (ptid);
+ else
+ lwp = GET_PID (ptid);
+
+ for (lp = lwp_list; lp; lp = lp->next)
+ if (lwp == GET_LWP (lp->ptid))
+ return lp;
+
+ return NULL;
+}
+
+/* Call CALLBACK with its second argument set to DATA for every LWP in
+ the list. If CALLBACK returns 1 for a particular LWP, return a
+ pointer to the structure describing that LWP immediately.
+ Otherwise return NULL. */
+
+struct lwp_info *
+iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data)
+{
+ struct lwp_info *lp, *lpnext;
+
+ for (lp = lwp_list; lp; lp = lpnext)
+ {
+ lpnext = lp->next;
+ if ((*callback) (lp, data))
+ return lp;
+ }
+
+ return NULL;
+}
+
+/* Attach to the LWP specified by PID. If VERBOSE is non-zero, print
+ a message telling the user that a new LWP has been added to the
+ process. */
+
+void
+lin_lwp_attach_lwp (ptid_t ptid, int verbose)
+{
+ struct lwp_info *lp, *found_lp;
+
+ gdb_assert (is_lwp (ptid));
+
+ /* Make sure SIGCHLD is blocked. We don't want SIGCHLD events
+ to interrupt either the ptrace() or waitpid() calls below. */
+ if (!sigismember (&blocked_mask, SIGCHLD))
+ {
+ sigaddset (&blocked_mask, SIGCHLD);
+ sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
+ }
+
+ if (verbose)
+ printf_filtered ("[New %s]\n", target_pid_to_str (ptid));
+
+ found_lp = lp = find_lwp_pid (ptid);
+ if (lp == NULL)
+ lp = add_lwp (ptid);
+
+ /* We assume that we're already attached to any LWP that has an id
+ equal to the overall process id, and to any LWP that is already
+ in our list of LWPs. If we're not seeing exit events from threads
+ and we've had PID wraparound since we last tried to stop all threads,
+ this assumption might be wrong; fortunately, this is very unlikely
+ to happen. */
+ if (GET_LWP (ptid) != GET_PID (ptid) && found_lp == NULL)
+ {
+ pid_t pid;
+ int status;
+
+ if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0)
+ error ("Can't attach %s: %s", target_pid_to_str (ptid),
+ safe_strerror (errno));
+
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
+ target_pid_to_str (ptid));
+
+ pid = waitpid (GET_LWP (ptid), &status, 0);
+ if (pid == -1 && errno == ECHILD)
+ {
+ /* Try again with __WCLONE to check cloned processes. */
+ pid = waitpid (GET_LWP (ptid), &status, __WCLONE);
+ lp->cloned = 1;
+ }
+
+ gdb_assert (pid == GET_LWP (ptid)
+ && WIFSTOPPED (status) && WSTOPSIG (status));
+
+ child_post_attach (pid);
+
+ lp->stopped = 1;
+
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "LLAL: waitpid %s received %s\n",
+ target_pid_to_str (ptid),
+ status_to_str (status));
+ }
+ }
+ else
+ {
+ /* We assume that the LWP representing the original process is
+ already stopped. Mark it as stopped in the data structure
+ that the linux ptrace layer uses to keep track of threads.
+ Note that this won't have already been done since the main
+ thread will have, we assume, been stopped by an attach from a
+ different layer. */
+ lp->stopped = 1;
+ }
+}
+
+static void
+linux_nat_attach (char *args, int from_tty)
+{
+ struct lwp_info *lp;
+ pid_t pid;
+ int status;
+
+ /* FIXME: We should probably accept a list of process id's, and
+ attach all of them. */
+ child_ops.to_attach (args, from_tty);
+
+ /* Add the initial process as the first LWP to the list. */
+ lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid)));
+
+ /* Make sure the initial process is stopped. The user-level threads
+ layer might want to poke around in the inferior, and that won't
+ work if things haven't stabilized yet. */
+ pid = waitpid (GET_PID (inferior_ptid), &status, 0);
+ if (pid == -1 && errno == ECHILD)
+ {
+ warning ("%s is a cloned process", target_pid_to_str (inferior_ptid));
+
+ /* Try again with __WCLONE to check cloned processes. */
+ pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE);
+ lp->cloned = 1;
+ }
+
+ gdb_assert (pid == GET_PID (inferior_ptid)
+ && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP);
+
+ lp->stopped = 1;
+
+ /* Fake the SIGSTOP that core GDB expects. */
+ lp->status = W_STOPCODE (SIGSTOP);
+ lp->resumed = 1;
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "LLA: waitpid %ld, faking SIGSTOP\n", (long) pid);
+ }
+}
+
+static int
+detach_callback (struct lwp_info *lp, void *data)
+{
+ gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
+
+ if (debug_linux_nat && lp->status)
+ fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
+ strsignal (WSTOPSIG (lp->status)),
+ target_pid_to_str (lp->ptid));
+
+ while (lp->signalled && lp->stopped)
+ {
+ errno = 0;
+ if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0,
+ WSTOPSIG (lp->status)) < 0)
+ error ("Can't continue %s: %s", target_pid_to_str (lp->ptid),
+ safe_strerror (errno));
+
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str (lp->status));
+
+ lp->stopped = 0;
+ lp->signalled = 0;
+ lp->status = 0;
+ /* FIXME drow/2003-08-26: There was a call to stop_wait_callback
+ here. But since lp->signalled was cleared above,
+ stop_wait_callback didn't do anything; the process was left
+ running. Shouldn't we be waiting for it to stop?
+ I've removed the call, since stop_wait_callback now does do
+ something when called with lp->signalled == 0. */
+
+ gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
+ }
+
+ /* We don't actually detach from the LWP that has an id equal to the
+ overall process id just yet. */
+ if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
+ {
+ errno = 0;
+ if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
+ WSTOPSIG (lp->status)) < 0)
+ error ("Can't detach %s: %s", target_pid_to_str (lp->ptid),
+ safe_strerror (errno));
+
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "PTRACE_DETACH (%s, %s, 0) (OK)\n",
+ target_pid_to_str (lp->ptid),
+ strsignal (WSTOPSIG (lp->status)));
+
+ delete_lwp (lp->ptid);
+ }
+
+ return 0;
+}
+
+static void
+linux_nat_detach (char *args, int from_tty)
+{
+ iterate_over_lwps (detach_callback, NULL);
+
+ /* Only the initial process should be left right now. */
+ gdb_assert (num_lwps == 1);
+
+ trap_ptid = null_ptid;
+
+ /* Destroy LWP info; it's no longer valid. */
+ init_lwp_list ();
+
+ /* Restore the original signal mask. */
+ sigprocmask (SIG_SETMASK, &normal_mask, NULL);
+ sigemptyset (&blocked_mask);
+
+ inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid));
+ child_ops.to_detach (args, from_tty);
+}
+
+/* Resume LP. */
+
+static int
+resume_callback (struct lwp_info *lp, void *data)
+{
+ if (lp->stopped && lp->status == 0)
+ {
+ struct thread_info *tp;
+
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n",
+ target_pid_to_str (lp->ptid));
+ lp->stopped = 0;
+ lp->step = 0;
+ }
+
+ return 0;
+}
+
+static int
+resume_clear_callback (struct lwp_info *lp, void *data)
+{
+ lp->resumed = 0;
+ return 0;
+}
+
+static int
+resume_set_callback (struct lwp_info *lp, void *data)
+{
+ lp->resumed = 1;
+ return 0;
+}
+
+static void
+linux_nat_resume (ptid_t ptid, int step, enum target_signal signo)
+{
+ struct lwp_info *lp;
+ int resume_all;
+
+ /* A specific PTID means `step only this process id'. */
+ resume_all = (PIDGET (ptid) == -1);
+
+ if (resume_all)
+ iterate_over_lwps (resume_set_callback, NULL);
+ else
+ iterate_over_lwps (resume_clear_callback, NULL);
+
+ /* If PID is -1, it's the current inferior that should be
+ handled specially. */
+ if (PIDGET (ptid) == -1)
+ ptid = inferior_ptid;
+
+ lp = find_lwp_pid (ptid);
+ if (lp)
+ {
+ ptid = pid_to_ptid (GET_LWP (lp->ptid));
+
+ /* Remember if we're stepping. */
+ lp->step = step;
+
+ /* Mark this LWP as resumed. */
+ lp->resumed = 1;
+
+ /* If we have a pending wait status for this thread, there is no
+ point in resuming the process. */
+ if (lp->status)
+ {
+ /* FIXME: What should we do if we are supposed to continue
+ this thread with a signal? */
+ gdb_assert (signo == TARGET_SIGNAL_0);
+ return;
+ }
+
+ /* Mark LWP as not stopped to prevent it from being continued by
+ resume_callback. */
+ lp->stopped = 0;
+ }
+
+ if (resume_all)
+ iterate_over_lwps (resume_callback, NULL);
+
+ child_resume (ptid, step, signo);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLR: %s %s, %s (resume event thread)\n",
+ step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (ptid),
+ signo ? strsignal (signo) : "0");
+}
+
+/* Issue kill to specified lwp. */
+
+static int tkill_failed;
+
+static int
+kill_lwp (int lwpid, int signo)
+{
+ errno = 0;
+
+/* Use tkill, if possible, in case we are using nptl threads. If tkill
+ fails, then we are not using nptl threads and we should be using kill. */
+
+#ifdef HAVE_TKILL_SYSCALL
+ if (!tkill_failed)
+ {
+ int ret = syscall (__NR_tkill, lwpid, signo);
+ if (errno != ENOSYS)
+ return ret;
+ errno = 0;
+ tkill_failed = 1;
+ }
+#endif
+
+ return kill (lwpid, signo);
+}
+
+/* Handle a GNU/Linux extended wait response. Most of the work we
+ just pass off to linux_handle_extended_wait, but if it reports a
+ clone event we need to add the new LWP to our list (and not report
+ the trap to higher layers). This function returns non-zero if
+ the event should be ignored and we should wait again. */
+
+static int
+linux_nat_handle_extended (struct lwp_info *lp, int status)
+{
+ linux_handle_extended_wait (GET_LWP (lp->ptid), status,
+ &lp->waitstatus);
+
+ /* TARGET_WAITKIND_SPURIOUS is used to indicate clone events. */
+ if (lp->waitstatus.kind == TARGET_WAITKIND_SPURIOUS)
+ {
+ struct lwp_info *new_lp;
+ new_lp = add_lwp (BUILD_LWP (lp->waitstatus.value.related_pid,
+ GET_PID (inferior_ptid)));
+ new_lp->cloned = 1;
+ new_lp->stopped = 1;
+
+ lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
+
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLHE: Got clone event from LWP %ld, resuming\n",
+ GET_LWP (lp->ptid));
+ ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+
+ return 1;
+ }
+
+ return 0;
+}
+
+/* Wait for LP to stop. Returns the wait status, or 0 if the LWP has
+ exited. */
+
+static int
+wait_lwp (struct lwp_info *lp)
+{
+ pid_t pid;
+ int status;
+ int thread_dead = 0;
+
+ gdb_assert (!lp->stopped);
+ gdb_assert (lp->status == 0);
+
+ pid = waitpid (GET_LWP (lp->ptid), &status, 0);
+ if (pid == -1 && errno == ECHILD)
+ {
+ pid = waitpid (GET_LWP (lp->ptid), &status, __WCLONE);
+ if (pid == -1 && errno == ECHILD)
+ {
+ /* The thread has previously exited. We need to delete it
+ now because, for some vendor 2.4 kernels with NPTL
+ support backported, there won't be an exit event unless
+ it is the main thread. 2.6 kernels will report an exit
+ event for each thread that exits, as expected. */
+ thread_dead = 1;
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog, "WL: %s vanished.\n",
+ target_pid_to_str (lp->ptid));
+ }
+ }
+
+ if (!thread_dead)
+ {
+ gdb_assert (pid == GET_LWP (lp->ptid));
+
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "WL: waitpid %s received %s\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str (status));
+ }
+ }
+
+ /* Check if the thread has exited. */
+ if (WIFEXITED (status) || WIFSIGNALED (status))
+ {
+ thread_dead = 1;
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog, "WL: %s exited.\n",
+ target_pid_to_str (lp->ptid));
+ }
+
+ if (thread_dead)
+ {
+ if (in_thread_list (lp->ptid))
+ {
+ /* Core GDB cannot deal with us deleting the current thread. */
+ if (!ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
+ printf_unfiltered ("[%s exited]\n",
+ target_pid_to_str (lp->ptid));
+ }
+
+ delete_lwp (lp->ptid);
+ return 0;
+ }
+
+ gdb_assert (WIFSTOPPED (status));
+
+ /* Handle GNU/Linux's extended waitstatus for trace events. */
+ if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "WL: Handling extended status 0x%06x\n",
+ status);
+ if (linux_nat_handle_extended (lp, status))
+ return wait_lwp (lp);
+ }
+
+ return status;
+}
+
+/* Send a SIGSTOP to LP. */
+
+static int
+stop_callback (struct lwp_info *lp, void *data)
+{
+ if (!lp->stopped && !lp->signalled)
+ {
+ int ret;
+
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SC: kill %s **<SIGSTOP>**\n",
+ target_pid_to_str (lp->ptid));
+ }
+ errno = 0;
+ ret = kill_lwp (GET_LWP (lp->ptid), SIGSTOP);
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SC: lwp kill %d %s\n",
+ ret,
+ errno ? safe_strerror (errno) : "ERRNO-OK");
+ }
+
+ lp->signalled = 1;
+ gdb_assert (lp->status == 0);
+ }
+
+ return 0;
+}
+
+/* Wait until LP is stopped. If DATA is non-null it is interpreted as
+ a pointer to a set of signals to be flushed immediately. */
+
+static int
+stop_wait_callback (struct lwp_info *lp, void *data)
+{
+ sigset_t *flush_mask = data;
+
+ if (!lp->stopped)
+ {
+ int status;
+
+ status = wait_lwp (lp);
+ if (status == 0)
+ return 0;
+
+ /* Ignore any signals in FLUSH_MASK. */
+ if (flush_mask && sigismember (flush_mask, WSTOPSIG (status)))
+ {
+ if (!lp->signalled)
+ {
+ lp->stopped = 1;
+ return 0;
+ }
+
+ errno = 0;
+ ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "PTRACE_CONT %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
+ return stop_wait_callback (lp, flush_mask);
+ }
+
+ if (WSTOPSIG (status) != SIGSTOP)
+ {
+ if (WSTOPSIG (status) == SIGTRAP)
+ {
+ /* If a LWP other than the LWP that we're reporting an
+ event for has hit a GDB breakpoint (as opposed to
+ some random trap signal), then just arrange for it to
+ hit it again later. We don't keep the SIGTRAP status
+ and don't forward the SIGTRAP signal to the LWP. We
+ will handle the current event, eventually we will
+ resume all LWPs, and this one will get its breakpoint
+ trap again.
+
+ If we do not do this, then we run the risk that the
+ user will delete or disable the breakpoint, but the
+ thread will have already tripped on it. */
+
+ /* Now resume this LWP and get the SIGSTOP event. */
+ errno = 0;
+ ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "PTRACE_CONT %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: Candidate SIGTRAP event in %s\n",
+ target_pid_to_str (lp->ptid));
+ }
+ /* Hold the SIGTRAP for handling by linux_nat_wait. */
+ stop_wait_callback (lp, data);
+ /* If there's another event, throw it back into the queue. */
+ if (lp->status)
+ {
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: kill %s, %s\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str ((int) status));
+ }
+ kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (lp->status));
+ }
+ /* Save the sigtrap event. */
+ lp->status = status;
+ return 0;
+ }
+ else
+ {
+ /* The thread was stopped with a signal other than
+ SIGSTOP, and didn't accidentally trip a breakpoint. */
+
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: Pending event %s in %s\n",
+ status_to_str ((int) status),
+ target_pid_to_str (lp->ptid));
+ }
+ /* Now resume this LWP and get the SIGSTOP event. */
+ errno = 0;
+ ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: PTRACE_CONT %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
+ /* Hold this event/waitstatus while we check to see if
+ there are any more (we still want to get that SIGSTOP). */
+ stop_wait_callback (lp, data);
+ /* If the lp->status field is still empty, use it to hold
+ this event. If not, then this event must be returned
+ to the event queue of the LWP. */
+ if (lp->status == 0)
+ lp->status = status;
+ else
+ {
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "SWC: kill %s, %s\n",
+ target_pid_to_str (lp->ptid),
+ status_to_str ((int) status));
+ }
+ kill_lwp (GET_LWP (lp->ptid), WSTOPSIG (status));
+ }
+ return 0;
+ }
+ }
+ else
+ {
+ /* We caught the SIGSTOP that we intended to catch, so
+ there's no SIGSTOP pending. */
+ lp->stopped = 1;
+ lp->signalled = 0;
+ }
+ }
+
+ return 0;
+}
+
+/* Check whether PID has any pending signals in FLUSH_MASK. If so set
+ the appropriate bits in PENDING, and return 1 - otherwise return 0. */
+
+static int
+linux_nat_has_pending (int pid, sigset_t *pending, sigset_t *flush_mask)
+{
+ sigset_t blocked, ignored;
+ int i;
+
+ linux_proc_pending_signals (pid, pending, &blocked, &ignored);
+
+ if (!flush_mask)
+ return 0;
+
+ for (i = 1; i < NSIG; i++)
+ if (sigismember (pending, i))
+ if (!sigismember (flush_mask, i)
+ || sigismember (&blocked, i)
+ || sigismember (&ignored, i))
+ sigdelset (pending, i);
+
+ if (sigisemptyset (pending))
+ return 0;
+
+ return 1;
+}
+
+/* DATA is interpreted as a mask of signals to flush. If LP has
+ signals pending, and they are all in the flush mask, then arrange
+ to flush them. LP should be stopped, as should all other threads
+ it might share a signal queue with. */
+
+static int
+flush_callback (struct lwp_info *lp, void *data)
+{
+ sigset_t *flush_mask = data;
+ sigset_t pending, intersection, blocked, ignored;
+ int pid, status;
+
+ /* Normally, when an LWP exits, it is removed from the LWP list. The
+ last LWP isn't removed till later, however. So if there is only
+ one LWP on the list, make sure it's alive. */
+ if (lwp_list == lp && lp->next == NULL)
+ if (!linux_nat_thread_alive (lp->ptid))
+ return 0;
+
+ /* Just because the LWP is stopped doesn't mean that new signals
+ can't arrive from outside, so this function must be careful of
+ race conditions. However, because all threads are stopped, we
+ can assume that the pending mask will not shrink unless we resume
+ the LWP, and that it will then get another signal. We can't
+ control which one, however. */
+
+ if (lp->status)
+ {
+ if (debug_linux_nat)
+ printf_unfiltered ("FC: LP has pending status %06x\n", lp->status);
+ if (WIFSTOPPED (lp->status) && sigismember (flush_mask, WSTOPSIG (lp->status)))
+ lp->status = 0;
+ }
+
+ while (linux_nat_has_pending (GET_LWP (lp->ptid), &pending, flush_mask))
+ {
+ int ret;
+
+ errno = 0;
+ ret = ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0, 0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stderr,
+ "FC: Sent PTRACE_CONT, ret %d %d\n", ret, errno);
+
+ lp->stopped = 0;
+ stop_wait_callback (lp, flush_mask);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stderr,
+ "FC: Wait finished; saved status is %d\n",
+ lp->status);
+ }
+
+ return 0;
+}
+
+/* Return non-zero if LP has a wait status pending. */
+
+static int
+status_callback (struct lwp_info *lp, void *data)
+{
+ /* Only report a pending wait status if we pretend that this has
+ indeed been resumed. */
+ return (lp->status != 0 && lp->resumed);
+}
+
+/* Return non-zero if LP isn't stopped. */
+
+static int
+running_callback (struct lwp_info *lp, void *data)
+{
+ return (lp->stopped == 0 || (lp->status != 0 && lp->resumed));
+}
+
+/* Count the LWP's that have had events. */
+
+static int
+count_events_callback (struct lwp_info *lp, void *data)
+{
+ int *count = data;
+
+ gdb_assert (count != NULL);
+
+ /* Count only LWPs that have a SIGTRAP event pending. */
+ if (lp->status != 0
+ && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
+ (*count)++;
+
+ return 0;
+}
+
+/* Select the LWP (if any) that is currently being single-stepped. */
+
+static int
+select_singlestep_lwp_callback (struct lwp_info *lp, void *data)
+{
+ if (lp->step && lp->status != 0)
+ return 1;
+ else
+ return 0;
+}
+
+/* Select the Nth LWP that has had a SIGTRAP event. */
+
+static int
+select_event_lwp_callback (struct lwp_info *lp, void *data)
+{
+ int *selector = data;
+
+ gdb_assert (selector != NULL);
+
+ /* Select only LWPs that have a SIGTRAP event pending. */
+ if (lp->status != 0
+ && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP)
+ if ((*selector)-- == 0)
+ return 1;
+
+ return 0;
+}
+
+static int
+cancel_breakpoints_callback (struct lwp_info *lp, void *data)
+{
+ struct lwp_info *event_lp = data;
+
+ /* Leave the LWP that has been elected to receive a SIGTRAP alone. */
+ if (lp == event_lp)
+ return 0;
+
+ /* If a LWP other than the LWP that we're reporting an event for has
+ hit a GDB breakpoint (as opposed to some random trap signal),
+ then just arrange for it to hit it again later. We don't keep
+ the SIGTRAP status and don't forward the SIGTRAP signal to the
+ LWP. We will handle the current event, eventually we will resume
+ all LWPs, and this one will get its breakpoint trap again.
+
+ If we do not do this, then we run the risk that the user will
+ delete or disable the breakpoint, but the LWP will have already
+ tripped on it. */
+
+ if (lp->status != 0
+ && WIFSTOPPED (lp->status) && WSTOPSIG (lp->status) == SIGTRAP
+ && breakpoint_inserted_here_p (read_pc_pid (lp->ptid) -
+ DECR_PC_AFTER_BREAK))
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "CBC: Push back breakpoint for %s\n",
+ target_pid_to_str (lp->ptid));
+
+ /* Back up the PC if necessary. */
+ if (DECR_PC_AFTER_BREAK)
+ write_pc_pid (read_pc_pid (lp->ptid) - DECR_PC_AFTER_BREAK, lp->ptid);
+
+ /* Throw away the SIGTRAP. */
+ lp->status = 0;
+ }
+
+ return 0;
+}
+
+/* Select one LWP out of those that have events pending. */
+
+static void
+select_event_lwp (struct lwp_info **orig_lp, int *status)
+{
+ int num_events = 0;
+ int random_selector;
+ struct lwp_info *event_lp;
+
+ /* Record the wait status for the origional LWP. */
+ (*orig_lp)->status = *status;
+
+ /* Give preference to any LWP that is being single-stepped. */
+ event_lp = iterate_over_lwps (select_singlestep_lwp_callback, NULL);
+ if (event_lp != NULL)
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "SEL: Select single-step %s\n",
+ target_pid_to_str (event_lp->ptid));
+ }
+ else
+ {
+ /* No single-stepping LWP. Select one at random, out of those
+ which have had SIGTRAP events. */
+
+ /* First see how many SIGTRAP events we have. */
+ iterate_over_lwps (count_events_callback, &num_events);
+
+ /* Now randomly pick a LWP out of those that have had a SIGTRAP. */
+ random_selector = (int)
+ ((num_events * (double) rand ()) / (RAND_MAX + 1.0));
+
+ if (debug_linux_nat && num_events > 1)
+ fprintf_unfiltered (gdb_stdlog,
+ "SEL: Found %d SIGTRAP events, selecting #%d\n",
+ num_events, random_selector);
+
+ event_lp = iterate_over_lwps (select_event_lwp_callback,
+ &random_selector);
+ }
+
+ if (event_lp != NULL)
+ {
+ /* Switch the event LWP. */
+ *orig_lp = event_lp;
+ *status = event_lp->status;
+ }
+
+ /* Flush the wait status for the event LWP. */
+ (*orig_lp)->status = 0;
+}
+
+/* Return non-zero if LP has been resumed. */
+
+static int
+resumed_callback (struct lwp_info *lp, void *data)
+{
+ return lp->resumed;
+}
+
+#ifdef CHILD_WAIT
+
+/* We need to override child_wait to support attaching to cloned
+ processes, since a normal wait (as done by the default version)
+ ignores those processes. */
+
+/* Wait for child PTID to do something. Return id of the child,
+ minus_one_ptid in case of error; store status into *OURSTATUS. */
+
+ptid_t
+child_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
+{
+ int save_errno;
+ int status;
+ pid_t pid;
+
+ ourstatus->kind = TARGET_WAITKIND_IGNORE;
+
+ do
+ {
+ set_sigint_trap (); /* Causes SIGINT to be passed on to the
+ attached process. */
+ set_sigio_trap ();
+
+ pid = waitpid (GET_PID (ptid), &status, 0);
+ if (pid == -1 && errno == ECHILD)
+ /* Try again with __WCLONE to check cloned processes. */
+ pid = waitpid (GET_PID (ptid), &status, __WCLONE);
+
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "CW: waitpid %ld received %s\n",
+ (long) pid, status_to_str (status));
+ }
+
+ save_errno = errno;
+
+ /* Make sure we don't report an event for the exit of the
+ original program, if we've detached from it. */
+ if (pid != -1 && !WIFSTOPPED (status) && pid != GET_PID (inferior_ptid))
+ {
+ pid = -1;
+ save_errno = EINTR;
+ }
+
+ /* Check for stop events reported by a process we didn't already
+ know about - in this case, anything other than inferior_ptid.
+
+ 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. If we want to handle debugging of
+ CLONE_PTRACE processes we need to do more here, i.e. switch
+ to multi-threaded mode. */
+ if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP
+ && pid != GET_PID (inferior_ptid))
+ {
+ linux_record_stopped_pid (pid);
+ pid = -1;
+ save_errno = EINTR;
+ }
+
+ /* Handle GNU/Linux's extended waitstatus for trace events. */
+ if (pid != -1 && WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP
+ && status >> 16 != 0)
+ {
+ linux_handle_extended_wait (pid, status, ourstatus);
+
+ /* If we see a clone event, detach the child, and don't
+ report the event. It would be nice to offer some way to
+ switch into a non-thread-db based threaded mode at this
+ point. */
+ if (ourstatus->kind == TARGET_WAITKIND_SPURIOUS)
+ {
+ ptrace (PTRACE_DETACH, ourstatus->value.related_pid, 0, 0);
+ ourstatus->kind = TARGET_WAITKIND_IGNORE;
+ ptrace (PTRACE_CONT, pid, 0, 0);
+ pid = -1;
+ save_errno = EINTR;
+ }
+ }
+
+ clear_sigio_trap ();
+ clear_sigint_trap ();
+ }
+ while (pid == -1 && save_errno == EINTR);
+
+ if (pid == -1)
+ {
+ warning ("Child process unexpectedly missing: %s",
+ safe_strerror (errno));
+
+ /* Claim it exited with unknown signal. */
+ ourstatus->kind = TARGET_WAITKIND_SIGNALLED;
+ ourstatus->value.sig = TARGET_SIGNAL_UNKNOWN;
+ return minus_one_ptid;
+ }
+
+ if (ourstatus->kind == TARGET_WAITKIND_IGNORE)
+ store_waitstatus (ourstatus, status);
+
+ return pid_to_ptid (pid);
+}
+
+#endif
+
+/* Stop an active thread, verify it still exists, then resume it. */
+
+static int
+stop_and_resume_callback (struct lwp_info *lp, void *data)
+{
+ struct lwp_info *ptr;
+
+ if (!lp->stopped && !lp->signalled)
+ {
+ stop_callback (lp, NULL);
+ stop_wait_callback (lp, NULL);
+ /* Resume if the lwp still exists. */
+ for (ptr = lwp_list; ptr; ptr = ptr->next)
+ if (lp == ptr)
+ {
+ resume_callback (lp, NULL);
+ resume_set_callback (lp, NULL);
+ }
+ }
+ return 0;
+}
+
+static ptid_t
+linux_nat_wait (ptid_t ptid, struct target_waitstatus *ourstatus)
+{
+ struct lwp_info *lp = NULL;
+ int options = 0;
+ int status = 0;
+ pid_t pid = PIDGET (ptid);
+ sigset_t flush_mask;
+
+ sigemptyset (&flush_mask);
+
+ /* Make sure SIGCHLD is blocked. */
+ if (!sigismember (&blocked_mask, SIGCHLD))
+ {
+ sigaddset (&blocked_mask, SIGCHLD);
+ sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
+ }
+
+retry:
+
+ /* Make sure there is at least one LWP that has been resumed, at
+ least if there are any LWPs at all. */
+ gdb_assert (num_lwps == 0 || iterate_over_lwps (resumed_callback, NULL));
+
+ /* First check if there is a LWP with a wait status pending. */
+ if (pid == -1)
+ {
+ /* Any LWP that's been resumed will do. */
+ lp = iterate_over_lwps (status_callback, NULL);
+ if (lp)
+ {
+ status = lp->status;
+ lp->status = 0;
+
+ if (debug_linux_nat && status)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Using pending wait status %s for %s.\n",
+ status_to_str (status),
+ target_pid_to_str (lp->ptid));
+ }
+
+ /* But if we don't fine one, we'll have to wait, and check both
+ cloned and uncloned processes. We start with the cloned
+ processes. */
+ options = __WCLONE | WNOHANG;
+ }
+ else if (is_lwp (ptid))
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Waiting for specific LWP %s.\n",
+ target_pid_to_str (ptid));
+
+ /* We have a specific LWP to check. */
+ lp = find_lwp_pid (ptid);
+ gdb_assert (lp);
+ status = lp->status;
+ lp->status = 0;
+
+ if (debug_linux_nat && status)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Using pending wait status %s for %s.\n",
+ status_to_str (status),
+ target_pid_to_str (lp->ptid));
+
+ /* If we have to wait, take into account whether PID is a cloned
+ process or not. And we have to convert it to something that
+ the layer beneath us can understand. */
+ options = lp->cloned ? __WCLONE : 0;
+ pid = GET_LWP (ptid);
+ }
+
+ if (status && lp->signalled)
+ {
+ /* A pending SIGSTOP may interfere with the normal stream of
+ events. In a typical case where interference is a problem,
+ we have a SIGSTOP signal pending for LWP A while
+ single-stepping it, encounter an event in LWP B, and take the
+ pending SIGSTOP while trying to stop LWP A. After processing
+ the event in LWP B, LWP A is continued, and we'll never see
+ the SIGTRAP associated with the last time we were
+ single-stepping LWP A. */
+
+ /* Resume the thread. It should halt immediately returning the
+ pending SIGSTOP. */
+ registers_changed ();
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
+ TARGET_SIGNAL_0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s %s, 0, 0 (expect SIGSTOP)\n",
+ lp->step ? "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (lp->ptid));
+ lp->stopped = 0;
+ gdb_assert (lp->resumed);
+
+ /* This should catch the pending SIGSTOP. */
+ stop_wait_callback (lp, NULL);
+ }
+
+ set_sigint_trap (); /* Causes SIGINT to be passed on to the
+ attached process. */
+ set_sigio_trap ();
+
+ while (status == 0)
+ {
+ pid_t lwpid;
+
+ lwpid = waitpid (pid, &status, options);
+ if (lwpid > 0)
+ {
+ gdb_assert (pid == -1 || lwpid == pid);
+
+ if (debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: waitpid %ld received %s\n",
+ (long) lwpid, status_to_str (status));
+ }
+
+ lp = find_lwp_pid (pid_to_ptid (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. */
+ if (WIFSTOPPED (status) && !lp)
+ {
+ linux_record_stopped_pid (lwpid);
+ status = 0;
+ continue;
+ }
+
+ /* Make sure we don't report an event for the exit of an LWP not in
+ our list, i.e. not part of the current process. This can happen
+ if we detach from a program we original forked and then it
+ exits. */
+ if (!WIFSTOPPED (status) && !lp)
+ {
+ status = 0;
+ continue;
+ }
+
+ /* NOTE drow/2003-06-17: This code seems to be meant for debugging
+ CLONE_PTRACE processes which do not use the thread library -
+ otherwise we wouldn't find the new LWP this way. That doesn't
+ currently work, and the following code is currently unreachable
+ due to the two blocks above. If it's fixed some day, this code
+ should be broken out into a function so that we can also pick up
+ LWPs from the new interface. */
+ if (!lp)
+ {
+ lp = add_lwp (BUILD_LWP (lwpid, GET_PID (inferior_ptid)));
+ if (options & __WCLONE)
+ lp->cloned = 1;
+
+ if (threaded)
+ {
+ gdb_assert (WIFSTOPPED (status)
+ && WSTOPSIG (status) == SIGSTOP);
+ lp->signalled = 1;
+
+ if (!in_thread_list (inferior_ptid))
+ {
+ inferior_ptid = BUILD_LWP (GET_PID (inferior_ptid),
+ GET_PID (inferior_ptid));
+ add_thread (inferior_ptid);
+ }
+
+ add_thread (lp->ptid);
+ printf_unfiltered ("[New %s]\n",
+ target_pid_to_str (lp->ptid));
+ }
+ }
+
+ /* Handle GNU/Linux's extended waitstatus for trace events. */
+ if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP && status >> 16 != 0)
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Handling extended status 0x%06x\n",
+ status);
+ if (linux_nat_handle_extended (lp, status))
+ {
+ status = 0;
+ continue;
+ }
+ }
+
+ /* Check if the thread has exited. */
+ if ((WIFEXITED (status) || WIFSIGNALED (status)) && num_lwps > 1)
+ {
+ if (in_thread_list (lp->ptid))
+ {
+ /* Core GDB cannot deal with us deleting the current
+ thread. */
+ if (!ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
+ printf_unfiltered ("[%s exited]\n",
+ target_pid_to_str (lp->ptid));
+ }
+
+ /* If this is the main thread, we must stop all threads and
+ verify if they are still alive. This is because in the nptl
+ thread model, there is no signal issued for exiting LWPs
+ other than the main thread. We only get the main thread
+ exit signal once all child threads have already exited.
+ If we stop all the threads and use the stop_wait_callback
+ to check if they have exited we can determine whether this
+ signal should be ignored or whether it means the end of the
+ debugged application, regardless of which threading model
+ is being used. */
+ if (GET_PID (lp->ptid) == GET_LWP (lp->ptid))
+ {
+ lp->stopped = 1;
+ iterate_over_lwps (stop_and_resume_callback, NULL);
+ }
+
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s exited.\n",
+ target_pid_to_str (lp->ptid));
+
+ delete_lwp (lp->ptid);
+
+ /* If there is at least one more LWP, then the exit signal
+ was not the end of the debugged application and should be
+ ignored. */
+ if (num_lwps > 0)
+ {
+ /* Make sure there is at least one thread running. */
+ gdb_assert (iterate_over_lwps (running_callback, NULL));
+
+ /* Discard the event. */
+ status = 0;
+ continue;
+ }
+ }
+
+ /* Check if the current LWP has previously exited. In the nptl
+ thread model, LWPs other than the main thread do not issue
+ signals when they exit so we must check whenever the thread
+ has stopped. A similar check is made in stop_wait_callback(). */
+ if (num_lwps > 1 && !linux_nat_thread_alive (lp->ptid))
+ {
+ if (in_thread_list (lp->ptid))
+ {
+ /* Core GDB cannot deal with us deleting the current
+ thread. */
+ if (!ptid_equal (lp->ptid, inferior_ptid))
+ delete_thread (lp->ptid);
+ printf_unfiltered ("[%s exited]\n",
+ target_pid_to_str (lp->ptid));
+ }
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s exited.\n",
+ target_pid_to_str (lp->ptid));
+
+ delete_lwp (lp->ptid);
+
+ /* Make sure there is at least one thread running. */
+ gdb_assert (iterate_over_lwps (running_callback, NULL));
+
+ /* Discard the event. */
+ status = 0;
+ continue;
+ }
+
+ /* Make sure we don't report a SIGSTOP that we sent
+ ourselves in an attempt to stop an LWP. */
+ if (lp->signalled
+ && WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP)
+ {
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: Delayed SIGSTOP caught for %s.\n",
+ target_pid_to_str (lp->ptid));
+
+ /* This is a delayed SIGSTOP. */
+ lp->signalled = 0;
+
+ registers_changed ();
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step,
+ TARGET_SIGNAL_0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s %s, 0, 0 (discard SIGSTOP)\n",
+ lp->step ?
+ "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (lp->ptid));
+
+ lp->stopped = 0;
+ gdb_assert (lp->resumed);
+
+ /* Discard the event. */
+ status = 0;
+ continue;
+ }
+
+ break;
+ }
+
+ if (pid == -1)
+ {
+ /* Alternate between checking cloned and uncloned processes. */
+ options ^= __WCLONE;
+
+ /* And suspend every time we have checked both. */
+ if (options & __WCLONE)
+ sigsuspend (&suspend_mask);
+ }
+
+ /* We shouldn't end up here unless we want to try again. */
+ gdb_assert (status == 0);
+ }
+
+ clear_sigio_trap ();
+ clear_sigint_trap ();
+
+ gdb_assert (lp);
+
+ /* Don't report signals that GDB isn't interested in, such as
+ signals that are neither printed nor stopped upon. Stopping all
+ threads can be a bit time-consuming so if we want decent
+ performance with heavily multi-threaded programs, especially when
+ they're using a high frequency timer, we'd better avoid it if we
+ can. */
+
+ if (WIFSTOPPED (status))
+ {
+ int signo = target_signal_from_host (WSTOPSIG (status));
+
+ if (signal_stop_state (signo) == 0
+ && signal_print_state (signo) == 0
+ && signal_pass_state (signo) == 1)
+ {
+ /* FIMXE: kettenis/2001-06-06: Should we resume all threads
+ here? It is not clear we should. GDB may not expect
+ other threads to run. On the other hand, not resuming
+ newly attached threads may cause an unwanted delay in
+ getting them running. */
+ registers_changed ();
+ child_resume (pid_to_ptid (GET_LWP (lp->ptid)), lp->step, signo);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: %s %s, %s (preempt 'handle')\n",
+ lp->step ?
+ "PTRACE_SINGLESTEP" : "PTRACE_CONT",
+ target_pid_to_str (lp->ptid),
+ signo ? strsignal (signo) : "0");
+ lp->stopped = 0;
+ status = 0;
+ goto retry;
+ }
+
+ if (signo == TARGET_SIGNAL_INT && signal_pass_state (signo) == 0)
+ {
+ /* If ^C/BREAK is typed at the tty/console, SIGINT gets
+ forwarded to the entire process group, that is, all LWP's
+ will receive it. Since we only want to report it once,
+ we try to flush it from all LWPs except this one. */
+ sigaddset (&flush_mask, SIGINT);
+ }
+ }
+
+ /* This LWP is stopped now. */
+ lp->stopped = 1;
+
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog, "LLW: Candidate event %s in %s.\n",
+ status_to_str (status), target_pid_to_str (lp->ptid));
+
+ /* Now stop all other LWP's ... */
+ iterate_over_lwps (stop_callback, NULL);
+
+ /* ... and wait until all of them have reported back that they're no
+ longer running. */
+ iterate_over_lwps (stop_wait_callback, &flush_mask);
+ iterate_over_lwps (flush_callback, &flush_mask);
+
+ /* 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 (pid == -1)
+ select_event_lwp (&lp, &status);
+
+ /* Now that we've selected our final event LWP, cancel any
+ breakpoints in other LWPs that have hit a GDB breakpoint. See
+ the comment in cancel_breakpoints_callback to find out why. */
+ iterate_over_lwps (cancel_breakpoints_callback, lp);
+
+ /* If we're not running in "threaded" mode, we'll report the bare
+ process id. */
+
+ if (WIFSTOPPED (status) && WSTOPSIG (status) == SIGTRAP)
+ {
+ trap_ptid = (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLW: trap_ptid is %s.\n",
+ target_pid_to_str (trap_ptid));
+ }
+ else
+ trap_ptid = null_ptid;
+
+ if (lp->waitstatus.kind != TARGET_WAITKIND_IGNORE)
+ {
+ *ourstatus = lp->waitstatus;
+ lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
+ }
+ else
+ store_waitstatus (ourstatus, status);
+
+ return (threaded ? lp->ptid : pid_to_ptid (GET_LWP (lp->ptid)));
+}
+
+static int
+kill_callback (struct lwp_info *lp, void *data)
+{
+ errno = 0;
+ ptrace (PTRACE_KILL, GET_LWP (lp->ptid), 0, 0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "KC: PTRACE_KILL %s, 0, 0 (%s)\n",
+ target_pid_to_str (lp->ptid),
+ errno ? safe_strerror (errno) : "OK");
+
+ return 0;
+}
+
+static int
+kill_wait_callback (struct lwp_info *lp, void *data)
+{
+ pid_t pid;
+
+ /* We must make sure that there are no pending events (delayed
+ SIGSTOPs, pending SIGTRAPs, etc.) to make sure the current
+ program doesn't interfere with any following debugging session. */
+
+ /* For cloned processes we must check both with __WCLONE and
+ without, since the exit status of a cloned process isn't reported
+ with __WCLONE. */
+ if (lp->cloned)
+ {
+ do
+ {
+ pid = waitpid (GET_LWP (lp->ptid), NULL, __WCLONE);
+ if (pid != (pid_t) -1 && debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "KWC: wait %s received unknown.\n",
+ target_pid_to_str (lp->ptid));
+ }
+ }
+ while (pid == GET_LWP (lp->ptid));
+
+ gdb_assert (pid == -1 && errno == ECHILD);
+ }
+
+ do
+ {
+ pid = waitpid (GET_LWP (lp->ptid), NULL, 0);
+ if (pid != (pid_t) -1 && debug_linux_nat)
+ {
+ fprintf_unfiltered (gdb_stdlog,
+ "KWC: wait %s received unk.\n",
+ target_pid_to_str (lp->ptid));
+ }
+ }
+ while (pid == GET_LWP (lp->ptid));
+
+ gdb_assert (pid == -1 && errno == ECHILD);
+ return 0;
+}
+
+static void
+linux_nat_kill (void)
+{
+ /* Kill all LWP's ... */
+ iterate_over_lwps (kill_callback, NULL);
+
+ /* ... and wait until we've flushed all events. */
+ iterate_over_lwps (kill_wait_callback, NULL);
+
+ target_mourn_inferior ();
+}
+
+static void
+linux_nat_create_inferior (char *exec_file, char *allargs, char **env,
+ int from_tty)
+{
+ child_ops.to_create_inferior (exec_file, allargs, env, from_tty);
+}
+
+static void
+linux_nat_mourn_inferior (void)
+{
+ trap_ptid = null_ptid;
+
+ /* Destroy LWP info; it's no longer valid. */
+ init_lwp_list ();
+
+ /* Restore the original signal mask. */
+ sigprocmask (SIG_SETMASK, &normal_mask, NULL);
+ sigemptyset (&blocked_mask);
+
+ child_ops.to_mourn_inferior ();
+}
+
+static int
+linux_nat_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len, int write,
+ struct mem_attrib *attrib, struct target_ops *target)
+{
+ struct cleanup *old_chain = save_inferior_ptid ();
+ int xfer;
+
+ if (is_lwp (inferior_ptid))
+ inferior_ptid = pid_to_ptid (GET_LWP (inferior_ptid));
+
+ xfer = linux_proc_xfer_memory (memaddr, myaddr, len, write, attrib, target);
+ if (xfer == 0)
+ xfer = child_xfer_memory (memaddr, myaddr, len, write, attrib, target);
+
+ do_cleanups (old_chain);
+ return xfer;
+}
+
+static int
+linux_nat_thread_alive (ptid_t ptid)
+{
+ gdb_assert (is_lwp (ptid));
+
+ errno = 0;
+ ptrace (PTRACE_PEEKUSER, GET_LWP (ptid), 0, 0);
+ if (debug_linux_nat)
+ fprintf_unfiltered (gdb_stdlog,
+ "LLTA: PTRACE_PEEKUSER %s, 0, 0 (%s)\n",
+ target_pid_to_str (ptid),
+ errno ? safe_strerror (errno) : "OK");
+ if (errno)
+ return 0;
+
+ return 1;
+}
+
+static char *
+linux_nat_pid_to_str (ptid_t ptid)
+{
+ static char buf[64];
+
+ if (is_lwp (ptid))
+ {
+ snprintf (buf, sizeof (buf), "LWP %ld", GET_LWP (ptid));
+ return buf;
+ }
+
+ return normal_pid_to_str (ptid);
+}
+
+static void
+init_linux_nat_ops (void)
+{
+#if 0
+ linux_nat_ops.to_open = linux_nat_open;
+#endif
+ linux_nat_ops.to_shortname = "lwp-layer";
+ linux_nat_ops.to_longname = "lwp-layer";
+ linux_nat_ops.to_doc = "Low level threads support (LWP layer)";
+ linux_nat_ops.to_attach = linux_nat_attach;
+ linux_nat_ops.to_detach = linux_nat_detach;
+ linux_nat_ops.to_resume = linux_nat_resume;
+ linux_nat_ops.to_wait = linux_nat_wait;
+ /* fetch_inferior_registers and store_inferior_registers will
+ honor the LWP id, so we can use them directly. */
+ linux_nat_ops.to_fetch_registers = fetch_inferior_registers;
+ linux_nat_ops.to_store_registers = store_inferior_registers;
+ linux_nat_ops.to_xfer_memory = linux_nat_xfer_memory;
+ linux_nat_ops.to_kill = linux_nat_kill;
+ linux_nat_ops.to_create_inferior = linux_nat_create_inferior;
+ linux_nat_ops.to_mourn_inferior = linux_nat_mourn_inferior;
+ linux_nat_ops.to_thread_alive = linux_nat_thread_alive;
+ linux_nat_ops.to_pid_to_str = linux_nat_pid_to_str;
+ linux_nat_ops.to_post_startup_inferior = child_post_startup_inferior;
+ linux_nat_ops.to_post_attach = child_post_attach;
+ linux_nat_ops.to_insert_fork_catchpoint = child_insert_fork_catchpoint;
+ linux_nat_ops.to_insert_vfork_catchpoint = child_insert_vfork_catchpoint;
+ linux_nat_ops.to_insert_exec_catchpoint = child_insert_exec_catchpoint;
+
+ linux_nat_ops.to_stratum = thread_stratum;
+ linux_nat_ops.to_has_thread_control = tc_schedlock;
+ linux_nat_ops.to_magic = OPS_MAGIC;
+}
+
+static void
+sigchld_handler (int signo)
+{
+ /* Do nothing. The only reason for this handler is that it allows
+ us to use sigsuspend in linux_nat_wait above to wait for the
+ arrival of a SIGCHLD. */
+}
+
+void
+_initialize_linux_nat (void)
+{
+ struct sigaction action;
+
+ extern void thread_db_init (struct target_ops *);
+
+ init_linux_nat_ops ();
+ add_target (&linux_nat_ops);
+ thread_db_init (&linux_nat_ops);
+
+ /* Save the original signal mask. */
+ sigprocmask (SIG_SETMASK, NULL, &normal_mask);
+
+ action.sa_handler = sigchld_handler;
+ sigemptyset (&action.sa_mask);
+ action.sa_flags = 0;
+ sigaction (SIGCHLD, &action, NULL);
+
+ /* Make sure we don't block SIGCHLD during a sigsuspend. */
+ sigprocmask (SIG_SETMASK, NULL, &suspend_mask);
+ sigdelset (&suspend_mask, SIGCHLD);
+
+ sigemptyset (&blocked_mask);
+
+ deprecated_add_show_from_set
+ (add_set_cmd ("lin-lwp", no_class, var_zinteger,
+ (char *) &debug_linux_nat,
+ "Set debugging of GNU/Linux lwp module.\n\
+Enables printf debugging output.\n", &setdebuglist), &showdebuglist);
+}
+\f
+
+/* FIXME: kettenis/2000-08-26: The stuff on this page is specific to
+ the GNU/Linux Threads library and therefore doesn't really belong
+ here. */
+
+/* Read variable NAME in the target and return its value if found.
+ Otherwise return zero. It is assumed that the type of the variable
+ is `int'. */
+
+static int
+get_signo (const char *name)
+{
+ struct minimal_symbol *ms;
+ int signo;
+
+ ms = lookup_minimal_symbol (name, NULL, NULL);
+ if (ms == NULL)
+ return 0;
+
+ if (target_read_memory (SYMBOL_VALUE_ADDRESS (ms), (char *) &signo,
+ sizeof (signo)) != 0)
+ return 0;
+
+ return signo;
+}
+
+/* Return the set of signals used by the threads library in *SET. */
+
+void
+lin_thread_get_thread_signals (sigset_t *set)
+{
+ struct sigaction action;
+ int restart, cancel;
+
+ sigemptyset (set);
+
+ restart = get_signo ("__pthread_sig_restart");
+ if (restart == 0)
+ return;
+
+ cancel = get_signo ("__pthread_sig_cancel");
+ if (cancel == 0)
+ return;
+
+ sigaddset (set, restart);
+ sigaddset (set, cancel);
+
+ /* The GNU/Linux Threads library makes terminating threads send a
+ special "cancel" signal instead of SIGCHLD. Make sure we catch
+ those (to prevent them from terminating GDB itself, which is
+ likely to be their default action) and treat them the same way as
+ SIGCHLD. */
+
+ action.sa_handler = sigchld_handler;
+ sigemptyset (&action.sa_mask);
+ action.sa_flags = 0;
+ sigaction (cancel, &action, NULL);
+
+ /* We block the "cancel" signal throughout this code ... */
+ sigaddset (&blocked_mask, cancel);
+ sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
+
+ /* ... except during a sigsuspend. */
+ sigdelset (&suspend_mask, cancel);
+}
projects / binutils-gdb.git / commitdiff