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a2f23071c9
* configure.in: Check for <gnu/libc-version.h>. * configure: Regenerate. * config.in: Regenerate. * linux-nat.h: Include "target.h". Add waitstatus field to struct lwp_info. * lin-lwp.c (add_lwp): Initialize waitstatus.kind. (lin_lwp_attach_lwp): Don't attach to LWPs we have already attached to. (lin_lwp_handle_extended): New function. Handle clone events. (wait_lwp): Use lin_lwp_handle_extended. Update comment about thread exit events. (child_wait): Handle clone events. (lin_lwp_wait: Use lin_lwp_handle_extended and handle clone events. * linux-nat.c (linux_enable_event_reporting): Turn on PTRACE_O_TRACECLONE. (linux_handle_extended_wait): Handle clone events. * thread-db.c: Include <gnu/libc-version.h>. (struct private_thread_info): Add dying flag. (enable_thread_event_reporting): Enable TD_DEATH for glibc 2.2 and higher. (attach_thread): Update comments. Handle dying threads. (detach_thread): Set the dying flag. (check_event): Always call attach_thread.
1969 lines
54 KiB
C
1969 lines
54 KiB
C
/* Multi-threaded debugging support for GNU/Linux (LWP layer).
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Copyright 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
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This file is part of GDB.
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include "defs.h"
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#include "gdb_assert.h"
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#include "gdb_string.h"
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#include <errno.h>
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#include <signal.h>
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#ifdef HAVE_TKILL_SYSCALL
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#include <unistd.h>
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#include <sys/syscall.h>
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#endif
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#include <sys/ptrace.h>
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#include "gdb_wait.h"
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#include "gdbthread.h"
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#include "inferior.h"
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#include "target.h"
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#include "regcache.h"
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#include "gdbcmd.h"
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static int debug_lin_lwp;
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extern char *strsignal (int sig);
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#include "linux-nat.h"
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/* On GNU/Linux there are no real LWP's. The closest thing to LWP's
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are processes sharing the same VM space. A multi-threaded process
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is basically a group of such processes. However, such a grouping
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is almost entirely a user-space issue; the kernel doesn't enforce
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such a grouping at all (this might change in the future). In
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general, we'll rely on the threads library (i.e. the GNU/Linux
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Threads library) to provide such a grouping.
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It is perfectly well possible to write a multi-threaded application
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without the assistance of a threads library, by using the clone
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system call directly. This module should be able to give some
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rudimentary support for debugging such applications if developers
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specify the CLONE_PTRACE flag in the clone system call, and are
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using the Linux kernel 2.4 or above.
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Note that there are some peculiarities in GNU/Linux that affect
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this code:
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- In general one should specify the __WCLONE flag to waitpid in
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order to make it report events for any of the cloned processes
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(and leave it out for the initial process). However, if a cloned
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process has exited the exit status is only reported if the
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__WCLONE flag is absent. Linux kernel 2.4 has a __WALL flag, but
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we cannot use it since GDB must work on older systems too.
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- When a traced, cloned process exits and is waited for by the
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debugger, the kernel reassigns it to the original parent and
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keeps it around as a "zombie". Somehow, the GNU/Linux Threads
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library doesn't notice this, which leads to the "zombie problem":
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When debugged a multi-threaded process that spawns a lot of
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threads will run out of processes, even if the threads exit,
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because the "zombies" stay around. */
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/* List of known LWPs. */
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static struct lwp_info *lwp_list;
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/* Number of LWPs in the list. */
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static int num_lwps;
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/* Non-zero if we're running in "threaded" mode. */
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static int threaded;
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#define GET_LWP(ptid) ptid_get_lwp (ptid)
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#define GET_PID(ptid) ptid_get_pid (ptid)
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#define is_lwp(ptid) (GET_LWP (ptid) != 0)
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#define BUILD_LWP(lwp, pid) ptid_build (pid, lwp, 0)
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/* If the last reported event was a SIGTRAP, this variable is set to
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the process id of the LWP/thread that got it. */
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ptid_t trap_ptid;
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/* This module's target-specific operations. */
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static struct target_ops lin_lwp_ops;
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/* The standard child operations. */
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extern struct target_ops child_ops;
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/* Since we cannot wait (in lin_lwp_wait) for the initial process and
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any cloned processes with a single call to waitpid, we have to use
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the WNOHANG flag and call waitpid in a loop. To optimize
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things a bit we use `sigsuspend' to wake us up when a process has
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something to report (it will send us a SIGCHLD if it has). To make
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this work we have to juggle with the signal mask. We save the
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original signal mask such that we can restore it before creating a
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new process in order to avoid blocking certain signals in the
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inferior. We then block SIGCHLD during the waitpid/sigsuspend
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loop. */
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/* Original signal mask. */
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static sigset_t normal_mask;
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/* Signal mask for use with sigsuspend in lin_lwp_wait, initialized in
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_initialize_lin_lwp. */
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static sigset_t suspend_mask;
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/* Signals to block to make that sigsuspend work. */
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static sigset_t blocked_mask;
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/* Prototypes for local functions. */
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static int stop_wait_callback (struct lwp_info *lp, void *data);
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static int lin_lwp_thread_alive (ptid_t ptid);
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/* Convert wait status STATUS to a string. Used for printing debug
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messages only. */
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static char *
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status_to_str (int status)
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{
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static char buf[64];
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if (WIFSTOPPED (status))
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snprintf (buf, sizeof (buf), "%s (stopped)",
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strsignal (WSTOPSIG (status)));
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else if (WIFSIGNALED (status))
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snprintf (buf, sizeof (buf), "%s (terminated)",
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strsignal (WSTOPSIG (status)));
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else
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snprintf (buf, sizeof (buf), "%d (exited)", WEXITSTATUS (status));
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return buf;
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}
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/* Initialize the list of LWPs. Note that this module, contrary to
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what GDB's generic threads layer does for its thread list,
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re-initializes the LWP lists whenever we mourn or detach (which
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doesn't involve mourning) the inferior. */
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static void
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init_lwp_list (void)
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{
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struct lwp_info *lp, *lpnext;
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for (lp = lwp_list; lp; lp = lpnext)
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{
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lpnext = lp->next;
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xfree (lp);
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}
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lwp_list = NULL;
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num_lwps = 0;
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threaded = 0;
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}
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/* Add the LWP specified by PID to the list. If this causes the
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number of LWPs to become larger than one, go into "threaded" mode.
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Return a pointer to the structure describing the new LWP. */
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static struct lwp_info *
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add_lwp (ptid_t ptid)
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{
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struct lwp_info *lp;
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gdb_assert (is_lwp (ptid));
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lp = (struct lwp_info *) xmalloc (sizeof (struct lwp_info));
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memset (lp, 0, sizeof (struct lwp_info));
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lp->waitstatus.kind = TARGET_WAITKIND_IGNORE;
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lp->ptid = ptid;
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lp->next = lwp_list;
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lwp_list = lp;
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if (++num_lwps > 1)
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threaded = 1;
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return lp;
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}
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/* Remove the LWP specified by PID from the list. */
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static void
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delete_lwp (ptid_t ptid)
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{
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struct lwp_info *lp, *lpprev;
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lpprev = NULL;
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for (lp = lwp_list; lp; lpprev = lp, lp = lp->next)
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if (ptid_equal (lp->ptid, ptid))
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break;
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if (!lp)
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return;
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/* We don't go back to "non-threaded" mode if the number of threads
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becomes less than two. */
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num_lwps--;
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if (lpprev)
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lpprev->next = lp->next;
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else
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lwp_list = lp->next;
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xfree (lp);
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}
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/* Return a pointer to the structure describing the LWP corresponding
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to PID. If no corresponding LWP could be found, return NULL. */
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static struct lwp_info *
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find_lwp_pid (ptid_t ptid)
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{
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struct lwp_info *lp;
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int lwp;
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if (is_lwp (ptid))
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lwp = GET_LWP (ptid);
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else
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lwp = GET_PID (ptid);
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for (lp = lwp_list; lp; lp = lp->next)
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if (lwp == GET_LWP (lp->ptid))
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return lp;
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return NULL;
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}
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/* Call CALLBACK with its second argument set to DATA for every LWP in
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the list. If CALLBACK returns 1 for a particular LWP, return a
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pointer to the structure describing that LWP immediately.
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Otherwise return NULL. */
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struct lwp_info *
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iterate_over_lwps (int (*callback) (struct lwp_info *, void *), void *data)
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{
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struct lwp_info *lp, *lpnext;
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for (lp = lwp_list; lp; lp = lpnext)
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{
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lpnext = lp->next;
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if ((*callback) (lp, data))
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return lp;
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}
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return NULL;
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}
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#if 0
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static void
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lin_lwp_open (char *args, int from_tty)
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{
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push_target (&lin_lwp_ops);
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}
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#endif
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/* Attach to the LWP specified by PID. If VERBOSE is non-zero, print
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a message telling the user that a new LWP has been added to the
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process. */
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void
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lin_lwp_attach_lwp (ptid_t ptid, int verbose)
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{
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struct lwp_info *lp, *found_lp;
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gdb_assert (is_lwp (ptid));
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/* Make sure SIGCHLD is blocked. We don't want SIGCHLD events
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to interrupt either the ptrace() or waitpid() calls below. */
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if (!sigismember (&blocked_mask, SIGCHLD))
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{
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sigaddset (&blocked_mask, SIGCHLD);
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sigprocmask (SIG_BLOCK, &blocked_mask, NULL);
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}
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if (verbose)
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printf_filtered ("[New %s]\n", target_pid_to_str (ptid));
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found_lp = lp = find_lwp_pid (ptid);
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if (lp == NULL)
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lp = add_lwp (ptid);
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/* We assume that we're already attached to any LWP that has an id
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equal to the overall process id, and to any LWP that is already
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in our list of LWPs. If we're not seeing exit events from threads
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and we've had PID wraparound since we last tried to stop all threads,
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this assumption might be wrong; fortunately, this is very unlikely
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to happen. */
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if (GET_LWP (ptid) != GET_PID (ptid) && found_lp == NULL)
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{
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pid_t pid;
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int status;
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if (ptrace (PTRACE_ATTACH, GET_LWP (ptid), 0, 0) < 0)
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error ("Can't attach %s: %s", target_pid_to_str (ptid),
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safe_strerror (errno));
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if (debug_lin_lwp)
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fprintf_unfiltered (gdb_stdlog,
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"LLAL: PTRACE_ATTACH %s, 0, 0 (OK)\n",
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target_pid_to_str (ptid));
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pid = waitpid (GET_LWP (ptid), &status, 0);
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if (pid == -1 && errno == ECHILD)
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{
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/* Try again with __WCLONE to check cloned processes. */
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pid = waitpid (GET_LWP (ptid), &status, __WCLONE);
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lp->cloned = 1;
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}
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gdb_assert (pid == GET_LWP (ptid)
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&& WIFSTOPPED (status) && WSTOPSIG (status));
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child_post_attach (pid);
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lp->stopped = 1;
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if (debug_lin_lwp)
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{
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fprintf_unfiltered (gdb_stdlog,
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"LLAL: waitpid %s received %s\n",
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target_pid_to_str (ptid),
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status_to_str (status));
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}
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}
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else
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{
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/* We assume that the LWP representing the original process
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is already stopped. Mark it as stopped in the data structure
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that the lin-lwp layer uses to keep track of threads. Note
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that this won't have already been done since the main thread
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will have, we assume, been stopped by an attach from a
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different layer. */
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lp->stopped = 1;
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}
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}
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static void
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lin_lwp_attach (char *args, int from_tty)
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{
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struct lwp_info *lp;
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pid_t pid;
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int status;
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/* FIXME: We should probably accept a list of process id's, and
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attach all of them. */
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child_ops.to_attach (args, from_tty);
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/* Add the initial process as the first LWP to the list. */
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lp = add_lwp (BUILD_LWP (GET_PID (inferior_ptid), GET_PID (inferior_ptid)));
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/* Make sure the initial process is stopped. The user-level threads
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layer might want to poke around in the inferior, and that won't
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work if things haven't stabilized yet. */
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pid = waitpid (GET_PID (inferior_ptid), &status, 0);
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if (pid == -1 && errno == ECHILD)
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{
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warning ("%s is a cloned process", target_pid_to_str (inferior_ptid));
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/* Try again with __WCLONE to check cloned processes. */
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pid = waitpid (GET_PID (inferior_ptid), &status, __WCLONE);
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lp->cloned = 1;
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}
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gdb_assert (pid == GET_PID (inferior_ptid)
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&& WIFSTOPPED (status) && WSTOPSIG (status) == SIGSTOP);
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lp->stopped = 1;
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/* Fake the SIGSTOP that core GDB expects. */
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lp->status = W_STOPCODE (SIGSTOP);
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lp->resumed = 1;
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if (debug_lin_lwp)
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{
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fprintf_unfiltered (gdb_stdlog,
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"LLA: waitpid %ld, faking SIGSTOP\n", (long) pid);
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}
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}
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static int
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detach_callback (struct lwp_info *lp, void *data)
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{
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gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
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if (debug_lin_lwp && lp->status)
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fprintf_unfiltered (gdb_stdlog, "DC: Pending %s for %s on detach.\n",
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strsignal (WSTOPSIG (lp->status)),
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target_pid_to_str (lp->ptid));
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while (lp->signalled && lp->stopped)
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{
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errno = 0;
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if (ptrace (PTRACE_CONT, GET_LWP (lp->ptid), 0,
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WSTOPSIG (lp->status)) < 0)
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error ("Can't continue %s: %s", target_pid_to_str (lp->ptid),
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safe_strerror (errno));
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if (debug_lin_lwp)
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fprintf_unfiltered (gdb_stdlog,
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"DC: PTRACE_CONTINUE (%s, 0, %s) (OK)\n",
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target_pid_to_str (lp->ptid),
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status_to_str (lp->status));
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lp->stopped = 0;
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lp->signalled = 0;
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lp->status = 0;
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/* FIXME drow/2003-08-26: There was a call to stop_wait_callback
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here. But since lp->signalled was cleared above,
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stop_wait_callback didn't do anything; the process was left
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running. Shouldn't we be waiting for it to stop?
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I've removed the call, since stop_wait_callback now does do
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something when called with lp->signalled == 0. */
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gdb_assert (lp->status == 0 || WIFSTOPPED (lp->status));
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}
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/* We don't actually detach from the LWP that has an id equal to the
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overall process id just yet. */
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if (GET_LWP (lp->ptid) != GET_PID (lp->ptid))
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{
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errno = 0;
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if (ptrace (PTRACE_DETACH, GET_LWP (lp->ptid), 0,
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WSTOPSIG (lp->status)) < 0)
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error ("Can't detach %s: %s", target_pid_to_str (lp->ptid),
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safe_strerror (errno));
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if (debug_lin_lwp)
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fprintf_unfiltered (gdb_stdlog,
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"PTRACE_DETACH (%s, %s, 0) (OK)\n",
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target_pid_to_str (lp->ptid),
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strsignal (WSTOPSIG (lp->status)));
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delete_lwp (lp->ptid);
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}
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return 0;
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}
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static void
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lin_lwp_detach (char *args, int from_tty)
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{
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iterate_over_lwps (detach_callback, NULL);
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/* Only the initial process should be left right now. */
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gdb_assert (num_lwps == 1);
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trap_ptid = null_ptid;
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/* Destroy LWP info; it's no longer valid. */
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init_lwp_list ();
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/* Restore the original signal mask. */
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sigprocmask (SIG_SETMASK, &normal_mask, NULL);
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sigemptyset (&blocked_mask);
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inferior_ptid = pid_to_ptid (GET_PID (inferior_ptid));
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child_ops.to_detach (args, from_tty);
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}
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/* Resume LP. */
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static int
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resume_callback (struct lwp_info *lp, void *data)
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{
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if (lp->stopped && lp->status == 0)
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{
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struct thread_info *tp;
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child_resume (pid_to_ptid (GET_LWP (lp->ptid)), 0, TARGET_SIGNAL_0);
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if (debug_lin_lwp)
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fprintf_unfiltered (gdb_stdlog,
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"RC: PTRACE_CONT %s, 0, 0 (resume sibling)\n",
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target_pid_to_str (lp->ptid));
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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");
|
||
}
|
||
|
||
|
||
/* 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;
|
||
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)
|
||
{
|
||
child_ops.to_create_inferior (exec_file, allargs, env);
|
||
}
|
||
|
||
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);
|
||
|
||
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);
|
||
}
|
||
|
||
|
||
/* 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);
|
||
}
|