freebsd-dev/lib/libpthread/thread/thr_exit.c
Jason Evans 6699b0c6fe Instead of using a join queue for each thread, use a single pointer to
keep track of a joiner.  POSIX only supports a single joiner, so this
simplification is acceptable.

At the same time, make sure to mark a joined thread as detached so that
its resources can be freed.

Reviewed by:	deischen
PR:		24345
2001-05-20 23:08:33 +00:00

241 lines
7.3 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 "pthread_private.h"
#define FLAGS_IN_SCHEDQ \
(PTHREAD_FLAGS_IN_PRIOQ|PTHREAD_FLAGS_IN_WAITQ|PTHREAD_FLAGS_IN_WORKQ)
__weak_reference(_pthread_exit, pthread_exit);
void _exit(int status)
{
int flags;
int i;
struct itimerval itimer;
/* Disable the interval timer: */
itimer.it_interval.tv_sec = 0;
itimer.it_interval.tv_usec = 0;
itimer.it_value.tv_sec = 0;
itimer.it_value.tv_usec = 0;
setitimer(_ITIMER_SCHED_TIMER, &itimer, NULL);
/* Close the pthread kernel pipe: */
__sys_close(_thread_kern_pipe[0]);
__sys_close(_thread_kern_pipe[1]);
/*
* Enter a loop to set all file descriptors to blocking
* if they were not created as non-blocking:
*/
for (i = 0; i < _thread_dtablesize; i++) {
/* Check if this file descriptor is in use: */
if (_thread_fd_table[i] != NULL &&
!(_thread_fd_table[i]->flags & O_NONBLOCK)) {
/* Get the current flags: */
flags = __sys_fcntl(i, F_GETFL, NULL);
/* Clear the nonblocking file descriptor flag: */
__sys_fcntl(i, F_SETFL, flags & ~O_NONBLOCK);
}
}
/* Call the _exit syscall: */
__sys_exit(status);
}
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)
{
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 owned fd locks: */
_thread_fd_unlock_owned(curthread);
/* 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();
pthread_t pthread;
/* 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_data != NULL) {
/* Run the thread-specific data destructors: */
_thread_cleanupspecific();
}
/* Free thread-specific poll_data structure, if allocated: */
if (curthread->poll_data.fds != NULL) {
free(curthread->poll_data.fds);
curthread->poll_data.fds = NULL;
}
/*
* Lock the garbage collector mutex to ensure that the garbage
* collector is not using the dead thread list.
*/
if (pthread_mutex_lock(&_gc_mutex) != 0)
PANIC("Cannot lock gc mutex");
/* Add this thread to the list of dead threads. */
TAILQ_INSERT_HEAD(&_dead_list, curthread, dle);
/*
* Signal the garbage collector thread that there is something
* to clean up.
*/
if (pthread_cond_signal(&_gc_cond) != 0)
PANIC("Cannot signal gc cond");
/*
* Avoid a race condition where a scheduling signal can occur
* causing the garbage collector thread to run. If this happens,
* the current thread can be cleaned out from under us.
*/
_thread_kern_sig_defer();
/* Unlock the garbage collector mutex: */
if (pthread_mutex_unlock(&_gc_mutex) != 0)
PANIC("Cannot unlock gc mutex");
/* Check if there is a thread joining this one: */
if (curthread->joiner != NULL) {
pthread = curthread->joiner;
curthread->joiner = NULL;
switch (pthread->suspended) {
case SUSP_JOIN:
/*
* The joining thread is suspended. Change the
* suspension state to make the thread runnable when it
* is resumed:
*/
pthread->suspended = SUSP_NO;
break;
case SUSP_NO:
/* Make the joining thread runnable: */
PTHREAD_NEW_STATE(pthread, PS_RUNNING);
break;
default:
PANIC("Unreachable code reached");
}
/* Set the return value for the joining thread: */
pthread->ret = curthread->ret;
pthread->error = 0;
/* 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;
}
/* Remove this thread from the thread list: */
TAILQ_REMOVE(&_thread_list, curthread, tle);
/* This thread will never be re-scheduled. */
_thread_kern_sched_state(PS_DEAD, __FILE__, __LINE__);
/* This point should not be reached. */
PANIC("Dead thread has resumed");
}