thr_exit.c revision 112965 
1/*
2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 *    notice, this list of conditions and the following disclaimer.
10 * 2. Redistributions in binary form must reproduce the above copyright
11 *    notice, this list of conditions and the following disclaimer in the
12 *    documentation and/or other materials provided with the distribution.
13 * 3. All advertising materials mentioning features or use of this software
14 *    must display the following acknowledgement:
15 *	This product includes software developed by John Birrell.
16 * 4. Neither the name of the author nor the names of any co-contributors
17 *    may be used to endorse or promote products derived from this software
18 *    without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: head/lib/libthr/thread/thr_exit.c 112965 2003-04-02 03:05:39Z jeff $
33 */
34#include <errno.h>
35#include <unistd.h>
36#include <fcntl.h>
37#include <stdio.h>
38#include <stdlib.h>
39#include <string.h>
40#include <pthread.h>
41#include "thr_private.h"
42
43__weak_reference(_pthread_exit, pthread_exit);
44
45void
46_thread_exit(char *fname, int lineno, char *string)
47{
48	char            s[256];
49
50	/* Prepare an error message string: */
51	snprintf(s, sizeof(s),
52	    "Fatal error '%s' at line %d in file %s (errno = %d)\n",
53	    string, lineno, fname, errno);
54
55	/* Write the string to the standard error file descriptor: */
56	__sys_write(2, s, strlen(s));
57
58	/* Force this process to exit: */
59	/* XXX - Do we want abort to be conditional on _PTHREADS_INVARIANTS? */
60#if defined(_PTHREADS_INVARIANTS)
61	abort();
62#else
63	__sys_exit(1);
64#endif
65}
66
67/*
68 * Only called when a thread is cancelled.  It may be more useful
69 * to call it from pthread_exit() if other ways of asynchronous or
70 * abnormal thread termination can be found.
71 */
72void
73_thread_exit_cleanup(void)
74{
75	/*
76	 * POSIX states that cancellation/termination of a thread should
77	 * not release any visible resources (such as mutexes) and that
78	 * it is the applications responsibility.  Resources that are
79	 * internal to the threads library, including file and fd locks,
80	 * are not visible to the application and need to be released.
81	 */
82	/* Unlock all private mutexes: */
83	_mutex_unlock_private(curthread);
84
85	/*
86	 * This still isn't quite correct because we don't account
87	 * for held spinlocks (see libc/stdlib/malloc.c).
88	 */
89}
90
91void
92_pthread_exit(void *status)
93{
94	pthread_t pthread;
95
96	/* Check if this thread is already in the process of exiting: */
97	if ((curthread->flags & PTHREAD_EXITING) != 0) {
98		char msg[128];
99		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);
100		PANIC(msg);
101	}
102
103	/* Flag this thread as exiting: */
104	curthread->flags |= PTHREAD_EXITING;
105
106	/* Save the return value: */
107	curthread->ret = status;
108
109	while (curthread->cleanup != NULL) {
110		pthread_cleanup_pop(1);
111	}
112	if (curthread->attr.cleanup_attr != NULL) {
113		curthread->attr.cleanup_attr(curthread->attr.arg_attr);
114	}
115	/* Check if there is thread specific data: */
116	if (curthread->specific != NULL) {
117		/* Run the thread-specific data destructors: */
118		_thread_cleanupspecific();
119	}
120
121	/*
122	 * Lock the garbage collector mutex to ensure that the garbage
123	 * collector is not using the dead thread list.
124	 */
125	if (pthread_mutex_lock(&_gc_mutex) != 0)
126		PANIC("Cannot lock gc mutex");
127
128	/* Add this thread to the list of dead threads. */
129	TAILQ_INSERT_HEAD(&_dead_list, curthread, dle);
130
131	/*
132	 * Signal the garbage collector thread that there is something
133	 * to clean up.
134	 */
135	if (pthread_cond_signal(&_gc_cond) != 0)
136		PANIC("Cannot signal gc cond");
137
138	/*
139	 * Avoid a race condition where a scheduling signal can occur
140	 * causing the garbage collector thread to run.  If this happens,
141	 * the current thread can be cleaned out from under us.
142	 */
143	GIANT_LOCK(curthread);
144
145	/* Unlock the garbage collector mutex. */
146	if (pthread_mutex_unlock(&_gc_mutex) != 0)
147		PANIC("Cannot unlock gc mutex");
148
149	/* Check if there is a thread joining this one: */
150	if (curthread->joiner != NULL) {
151		pthread = curthread->joiner;
152		curthread->joiner = NULL;
153
154		/* Make the joining thread runnable: */
155		PTHREAD_NEW_STATE(pthread, PS_RUNNING);
156
157		/* Set the return value for the joining thread: */
158		pthread->join_status.ret = curthread->ret;
159		pthread->join_status.error = 0;
160		pthread->join_status.thread = NULL;
161
162		/* Make this thread collectable by the garbage collector. */
163		PTHREAD_ASSERT(((curthread->attr.flags & PTHREAD_DETACHED) ==
164		    0), "Cannot join a detached thread");
165		curthread->attr.flags |= PTHREAD_DETACHED;
166	}
167
168	/* Remove this thread from the thread list: */
169	TAILQ_REMOVE(&_thread_list, curthread, tle);
170
171	PTHREAD_SET_STATE(curthread, PS_DEAD);
172	GIANT_UNLOCK(curthread);
173
174	/*
175	 * Retire the architecture specific id so that it can be used for
176	 * new threads.
177	 */
178	_retire_thread(curthread->arch_id);
179	_thr_exit();
180
181	/* This point should not be reached. */
182	PANIC("Dead thread has resumed");
183}
184