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/*
* 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"
__weak_reference(_pthread_exit, pthread_exit);
/* thr_exit() */
extern int _thr_exit(void);
void
_thread_exit(char *fname, int lineno, char *string)
{
char s[256];
/* Prepare an error message string: */
snprintf(s, sizeof(s),
"Fatal error '%s' at line %d in file %s (errno = %d)\n",
string, lineno, fname, errno);
/* Write the string to the standard error file descriptor: */
__sys_write(2, s, strlen(s));
/* Force this process to exit: */
/* XXX - Do we want abort to be conditional on _PTHREADS_INVARIANTS? */
#if defined(_PTHREADS_INVARIANTS)
abort();
#else
__sys_exit(1);
#endif
}
/*
* 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
_thread_exit_cleanup(void)
{
/*
* 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)
{
pthread_t pthread, joiner;
int exitNow = 0;
/* Check if this thread is already in the process of exiting: */
if ((curthread->flags & PTHREAD_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: */
curthread->flags |= PTHREAD_EXITING;
/* 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();
}
retry:
/*
* Proper lock order, to minimize deadlocks, between joining
* and exiting threads is: DEAD_LIST, THREAD_LIST, exiting, joiner.
* In order to do this *and* protect from races, we must resort
* this test-and-retry loop.
*/
joiner = curthread->joiner;
/* Lock the dead list first to maintain correct lock order */
DEAD_LIST_LOCK;
THREAD_LIST_LOCK;
_thread_critical_enter(curthread);
if (joiner != curthread->joiner) {
_thread_critical_exit(curthread);
THREAD_LIST_UNLOCK;
DEAD_LIST_UNLOCK;
goto retry;
}
/* Check if there is a thread joining this one: */
if (curthread->joiner != NULL) {
pthread = curthread->joiner;
UMTX_LOCK(&pthread->lock);
curthread->joiner = NULL;
/* Make the joining thread runnable: */
PTHREAD_NEW_STATE(pthread, PS_RUNNING);
/* Set the return value for the joining thread: */
pthread->join_status.ret = curthread->ret;
pthread->join_status.error = 0;
pthread->join_status.thread = NULL;
UMTX_UNLOCK(&pthread->lock);
/* Make this thread collectable by the garbage collector. */
PTHREAD_ASSERT(((curthread->attr.flags & PTHREAD_DETACHED) ==
0), "Cannot join a detached thread");
curthread->attr.flags |= PTHREAD_DETACHED;
}
/*
* Add this thread to the list of dead threads, and
* also remove it from the active threads list.
*/
TAILQ_INSERT_HEAD(&_dead_list, curthread, dle);
TAILQ_REMOVE(&_thread_list, curthread, tle);
PTHREAD_SET_STATE(curthread, PS_DEAD);
_thread_critical_exit(curthread);
/* If we're the last thread, call it quits */
if (TAILQ_EMPTY(&_thread_list))
exitNow = 1;
THREAD_LIST_UNLOCK;
/*
* Signal the garbage collector thread that there is something
* to clean up. But don't allow it to free the memory until after
* it is retired by holding on to the dead list lock.
*/
if (pthread_cond_signal(&_gc_cond) != 0)
PANIC("Cannot signal gc cond");
if (exitNow)
exit(0);
DEAD_LIST_UNLOCK;
/*
* This function will not return unless we are the last
* thread, which we can't be because we've already checked
* for that.
*/
_thr_exit();
/* This point should not be reached. */
PANIC("Dead thread has resumed");
}
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