thr_exit.c revision 136192 
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 136192 2004-10-06 14:23:00Z mtm $
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
45/* thr_exit() */
46extern int _thr_exit(long *state);
47
48static void	deadlist_free_threads();
49
50void
51_thread_exit(char *fname, int lineno, char *string)
52{
53	char            s[256];
54
55	/* Prepare an error message string: */
56	snprintf(s, sizeof(s),
57	    "Fatal error '%s' at line %d in file %s (errno = %d)\n",
58	    string, lineno, fname, errno);
59
60	/* Write the string to the standard error file descriptor: */
61	__sys_write(2, s, strlen(s));
62
63	/* Force this process to exit: */
64	/* XXX - Do we want abort to be conditional on _PTHREADS_INVARIANTS? */
65#if defined(_PTHREADS_INVARIANTS)
66	abort();
67#else
68	__sys_exit(1);
69#endif
70}
71
72/*
73 * Only called when a thread is cancelled.  It may be more useful
74 * to call it from pthread_exit() if other ways of asynchronous or
75 * abnormal thread termination can be found.
76 */
77void
78_thread_exit_cleanup(void)
79{
80	/*
81	 * POSIX states that cancellation/termination of a thread should
82	 * not release any visible resources (such as mutexes) and that
83	 * it is the applications responsibility.  Resources that are
84	 * internal to the threads library, including file and fd locks,
85	 * are not visible to the application and need to be released.
86	 */
87	/* Unlock all private mutexes: */
88	_mutex_unlock_private(curthread);
89
90	/*
91	 * This still isn't quite correct because we don't account
92	 * for held spinlocks (see libc/stdlib/malloc.c).
93	 */
94}
95
96void
97_pthread_exit(void *status)
98{
99	struct pthread *pthread;
100	int exitNow = 0;
101
102	/*
103	 * This thread will no longer handle any signals.
104	 */
105	_thread_sigblock();
106
107	/* Check if this thread is already in the process of exiting: */
108	if (curthread->exiting) {
109		char msg[128];
110		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);
111		PANIC(msg);
112	}
113
114	/* Flag this thread as exiting: */
115	curthread->exiting = 1;
116
117	/* Save the return value: */
118	curthread->ret = status;
119
120	while (curthread->cleanup != NULL) {
121		pthread_cleanup_pop(1);
122	}
123	if (curthread->attr.cleanup_attr != NULL) {
124		curthread->attr.cleanup_attr(curthread->attr.arg_attr);
125	}
126	/* Check if there is thread specific data: */
127	if (curthread->specific != NULL) {
128		/* Run the thread-specific data destructors: */
129		_thread_cleanupspecific();
130	}
131
132	/*
133	 * Remove read-write lock list. It is allocated as-needed.
134	 * Therefore, it must be checked for validity before freeing.
135	 */
136	if (curthread->rwlockList != NULL)
137		free(curthread->rwlockList);
138
139	/* Lock the dead list first to maintain correct lock order */
140	DEAD_LIST_LOCK;
141	THREAD_LIST_LOCK;
142
143	/* Check if there is a thread joining this one: */
144	if (curthread->joiner != NULL) {
145		pthread = curthread->joiner;
146		curthread->joiner = NULL;
147
148		/* Set the return value for the joining thread: */
149		pthread->join_status.ret = curthread->ret;
150		pthread->join_status.error = 0;
151		pthread->join_status.thread = NULL;
152
153		/* Make the joining thread runnable: */
154		PTHREAD_WAKE(pthread);
155
156		curthread->attr.flags |= PTHREAD_DETACHED;
157	}
158
159	/*
160	 * Free any memory allocated for dead threads.
161	 * Add this thread to the list of dead threads, and
162	 * also remove it from the active threads list.
163	 */
164	deadlist_free_threads();
165	TAILQ_INSERT_HEAD(&_dead_list, curthread, dle);
166	TAILQ_REMOVE(&_thread_list, curthread, tle);
167
168	/* If we're the last thread, call it quits */
169	if (TAILQ_EMPTY(&_thread_list))
170		exitNow = 1;
171
172	THREAD_LIST_UNLOCK;
173	DEAD_LIST_UNLOCK;
174
175	if (exitNow)
176		exit(0);
177
178	/*
179	 * This function will not return unless we are the last
180	 * thread, which we can't be because we've already checked
181	 * for that.
182	 */
183	_thr_exit((long *)&curthread->isdead);
184
185	/* This point should not be reached. */
186	PANIC("Dead thread has resumed");
187}
188
189/*
190 * Note: this function must be called with the dead thread list
191 *	 locked.
192 */
193static void
194deadlist_free_threads()
195{
196	struct pthread *ptd, *ptdTemp;
197
198	TAILQ_FOREACH_SAFE(ptd, &_dead_list, dle, ptdTemp) {
199		/* Don't destroy the initial thread or non-detached threads. */
200		if (ptd == _thread_initial ||
201		    (ptd->attr.flags & PTHREAD_DETACHED) == 0)
202			continue;
203		TAILQ_REMOVE(&_dead_list, ptd, dle);
204		deadlist_free_onethread(ptd);
205	}
206}
207
208void
209deadlist_free_onethread(struct pthread *ptd)
210{
211
212	if (ptd->attr.stackaddr_attr == NULL && ptd->stack != NULL) {
213		STACK_LOCK;
214		_thread_stack_free(ptd->stack, ptd->attr.stacksize_attr,
215		    ptd->attr.guardsize_attr);
216		STACK_UNLOCK;
217	}
218	_retire_thread(ptd->arch_id);
219	free(ptd);
220}
221