freebsd-dev/lib/libpthread/thread/thr_exit.c
David Xu fca6ccde6e Check unhandled signals before thread marks itself as DEAD,
this reduces chances of signal losting problem found by
Peter Holm <peter@holm.cc>
2004-10-23 23:37:54 +00:00

160 lines
5.4 KiB
C

/*
* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by John Birrell.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include "thr_private.h"
void _pthread_exit(void *status);
__weak_reference(_pthread_exit, pthread_exit);
void
_thr_exit(char *fname, int lineno, char *msg)
{
/* Write an error message to the standard error file descriptor: */
_thread_printf(2,
"Fatal error '%s' at line %d in file %s (errno = %d)\n",
msg, lineno, fname, errno);
abort();
}
/*
* Only called when a thread is cancelled. It may be more useful
* to call it from pthread_exit() if other ways of asynchronous or
* abnormal thread termination can be found.
*/
void
_thr_exit_cleanup(void)
{
struct pthread *curthread = _get_curthread();
/*
* POSIX states that cancellation/termination of a thread should
* not release any visible resources (such as mutexes) and that
* it is the applications responsibility. Resources that are
* internal to the threads library, including file and fd locks,
* are not visible to the application and need to be released.
*/
/* Unlock all private mutexes: */
_mutex_unlock_private(curthread);
/*
* This still isn't quite correct because we don't account
* for held spinlocks (see libc/stdlib/malloc.c).
*/
}
void
_pthread_exit(void *status)
{
struct pthread *curthread = _get_curthread();
kse_critical_t crit;
struct kse *curkse;
/* Check if this thread is already in the process of exiting: */
if ((curthread->flags & THR_FLAGS_EXITING) != 0) {
char msg[128];
snprintf(msg, sizeof(msg), "Thread %p has called "
"pthread_exit() from a destructor. POSIX 1003.1 "
"1996 s16.2.5.2 does not allow this!", curthread);
PANIC(msg);
}
/*
* Flag this thread as exiting. Threads should now be prevented
* from joining to this thread.
*/
THR_SCHED_LOCK(curthread, curthread);
curthread->flags |= THR_FLAGS_EXITING;
THR_SCHED_UNLOCK(curthread, curthread);
/*
* To avoid signal-lost problem, if signals had already been
* delivered to us, handle it. we have already set EXITING flag
* so no new signals should be delivered to us.
* XXX this is not enough if signal was delivered just before
* thread called sigprocmask and masked it! in this case, we
* might have to re-post the signal by kill() if the signal
* is targeting process (not for a specified thread).
* Kernel has same signal-lost problem, a signal may be delivered
* to a thread which is on the way to call sigprocmask or thr_exit()!
*/
if (curthread->check_pending)
_thr_sig_check_pending(curthread);
/* Save the return value: */
curthread->ret = status;
while (curthread->cleanup != NULL) {
pthread_cleanup_pop(1);
}
if (curthread->attr.cleanup_attr != NULL) {
curthread->attr.cleanup_attr(curthread->attr.arg_attr);
}
/* Check if there is thread specific data: */
if (curthread->specific != NULL) {
/* Run the thread-specific data destructors: */
_thread_cleanupspecific();
}
if (!_kse_isthreaded())
exit(0);
crit = _kse_critical_enter();
curkse = _get_curkse();
KSE_LOCK_ACQUIRE(curkse, &_thread_list_lock);
/* Use thread_list_lock */
_thread_active_threads--;
if ((_thread_scope_system <= 0 && _thread_active_threads == 1) ||
(_thread_scope_system > 0 && _thread_active_threads == 0)) {
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
_kse_critical_leave(crit);
exit(0);
/* Never reach! */
}
KSE_LOCK_RELEASE(curkse, &_thread_list_lock);
/* This thread will never be re-scheduled. */
KSE_LOCK(curkse);
THR_SET_STATE(curthread, PS_DEAD);
_thr_sched_switch_unlocked(curthread);
/* Never reach! */
/* This point should not be reached. */
PANIC("Dead thread has resumed");
}