freebsd-skq/lib/libkse/thread/thr_exit.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. 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 "namespace.h"
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include "un-namespace.h"
#include "thr_private.h"

void	_pthread_exit(void *status);

__weak_reference(_pthread_exit, pthread_exit);

void
_thr_exit(const char *fname, int lineno, const 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");
}