fd626336fd
lock held (_thr_sched_switch_unlocked()) and use this to avoid dropping the scheduler lock and having the scheduler retake the same lock again. Add a better way of detecting if a low-level lock is in use. When switching out a thread due to blocking in the UTS, don't switch to the KSE's scheduler stack only to switch back to another thread. If possible switch to the new thread directly from the old thread and avoid the overhead of the extra context switch. Check for pending signals on a thread when entering the scheduler and add them to the threads signal frame. This includes some other minor signal fixes. Most of this was a joint effor between davidxu and myself. Reviewed by: davidxu Approved by: re@ (blanket for libpthread)
134 lines
4.3 KiB
C
134 lines
4.3 KiB
C
/*
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* Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <errno.h>
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#include <unistd.h>
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#include <fcntl.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#include <pthread.h>
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#include "thr_private.h"
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void _pthread_exit(void *status);
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__weak_reference(_pthread_exit, pthread_exit);
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void
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_thr_exit(char *fname, int lineno, char *msg)
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{
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char s[256];
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/* Prepare an error message string: */
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snprintf(s, sizeof(s),
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"Fatal error '%s' at line %d in file %s (errno = %d)\n",
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msg, lineno, fname, errno);
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/* Write the string to the standard error file descriptor: */
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__sys_write(2, s, strlen(s));
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abort();
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}
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/*
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* Only called when a thread is cancelled. It may be more useful
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* to call it from pthread_exit() if other ways of asynchronous or
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* abnormal thread termination can be found.
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*/
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void
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_thr_exit_cleanup(void)
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{
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struct pthread *curthread = _get_curthread();
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/*
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* POSIX states that cancellation/termination of a thread should
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* not release any visible resources (such as mutexes) and that
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* it is the applications responsibility. Resources that are
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* internal to the threads library, including file and fd locks,
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* are not visible to the application and need to be released.
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*/
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/* Unlock all private mutexes: */
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_mutex_unlock_private(curthread);
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/*
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* This still isn't quite correct because we don't account
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* for held spinlocks (see libc/stdlib/malloc.c).
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*/
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}
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void
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_pthread_exit(void *status)
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{
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struct pthread *curthread = _get_curthread();
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/* Check if this thread is already in the process of exiting: */
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if ((curthread->flags & THR_FLAGS_EXITING) != 0) {
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char msg[128];
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snprintf(msg, sizeof(msg), "Thread %p has called "
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"pthread_exit() from a destructor. POSIX 1003.1 "
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"1996 s16.2.5.2 does not allow this!", curthread);
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PANIC(msg);
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}
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/*
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* Flag this thread as exiting. Threads should now be prevented
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* from joining to this thread.
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*/
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THR_SCHED_LOCK(curthread, curthread);
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curthread->flags |= THR_FLAGS_EXITING;
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THR_SCHED_UNLOCK(curthread, curthread);
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/* Save the return value: */
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curthread->ret = status;
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while (curthread->cleanup != NULL) {
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pthread_cleanup_pop(1);
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}
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if (curthread->attr.cleanup_attr != NULL) {
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curthread->attr.cleanup_attr(curthread->attr.arg_attr);
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}
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/* Check if there is thread specific data: */
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if (curthread->specific != NULL) {
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/* Run the thread-specific data destructors: */
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_thread_cleanupspecific();
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}
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/* This thread will never be re-scheduled. */
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THR_LOCK_SWITCH(curthread);
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THR_SET_STATE(curthread, PS_DEAD);
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_thr_sched_switch_unlocked(curthread);
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/* Never reach! */
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/* This point should not be reached. */
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PANIC("Dead thread has resumed");
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}
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