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 * $FreeBSD$ 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() */ 46 extern int _thr_exit(void); 47 48 static void deadlist_free_threads(); 49 50 void 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 */ 77 void 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 96 void 97 _pthread_exit(void *status) 98 { 99 pthread_t pthread, joiner; 100 int exitNow = 0; 101 102 /* Check if this thread is already in the process of exiting: */ 103 if ((curthread->flags & PTHREAD_EXITING) != 0) { 104 char msg[128]; 105 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); 106 PANIC(msg); 107 } 108 109 /* Flag this thread as exiting: */ 110 curthread->flags |= PTHREAD_EXITING; 111 112 /* Save the return value: */ 113 curthread->ret = status; 114 115 while (curthread->cleanup != NULL) { 116 pthread_cleanup_pop(1); 117 } 118 if (curthread->attr.cleanup_attr != NULL) { 119 curthread->attr.cleanup_attr(curthread->attr.arg_attr); 120 } 121 /* Check if there is thread specific data: */ 122 if (curthread->specific != NULL) { 123 /* Run the thread-specific data destructors: */ 124 _thread_cleanupspecific(); 125 } 126 127 /* 128 * Remove read-write lock list. It is allocated as-needed. 129 * Therefore, it must be checked for validity before freeing. 130 */ 131 if (curthread->rwlockList != NULL) 132 free(curthread->rwlockList); 133 retry: 134 /* 135 * Proper lock order, to minimize deadlocks, between joining 136 * and exiting threads is: DEAD_LIST, THREAD_LIST, exiting, joiner. 137 * In order to do this *and* protect from races, we must resort 138 * this test-and-retry loop. 139 */ 140 joiner = curthread->joiner; 141 142 /* Lock the dead list first to maintain correct lock order */ 143 DEAD_LIST_LOCK; 144 THREAD_LIST_LOCK; 145 _thread_critical_enter(curthread); 146 147 if (joiner != curthread->joiner) { 148 _thread_critical_exit(curthread); 149 THREAD_LIST_UNLOCK; 150 DEAD_LIST_UNLOCK; 151 goto retry; 152 } 153 154 /* Check if there is a thread joining this one: */ 155 if (curthread->joiner != NULL) { 156 pthread = curthread->joiner; 157 UMTX_LOCK(&pthread->lock); 158 curthread->joiner = NULL; 159 160 /* Make the joining thread runnable: */ 161 PTHREAD_NEW_STATE(pthread, PS_RUNNING); 162 163 /* Set the return value for the joining thread: */ 164 pthread->join_status.ret = curthread->ret; 165 pthread->join_status.error = 0; 166 pthread->join_status.thread = NULL; 167 UMTX_UNLOCK(&pthread->lock); 168 169 /* Make this thread collectable by the garbage collector. */ 170 PTHREAD_ASSERT(((curthread->attr.flags & PTHREAD_DETACHED) == 171 0), "Cannot join a detached thread"); 172 curthread->attr.flags |= PTHREAD_DETACHED; 173 } 174 175 /* 176 * Free any memory allocated for dead threads. 177 * Add this thread to the list of dead threads, and 178 * also remove it from the active threads list. 179 */ 180 deadlist_free_threads(); 181 TAILQ_INSERT_HEAD(&_dead_list, curthread, dle); 182 TAILQ_REMOVE(&_thread_list, curthread, tle); 183 PTHREAD_SET_STATE(curthread, PS_DEAD); 184 _thread_critical_exit(curthread); 185 186 /* If we're the last thread, call it quits */ 187 if (TAILQ_EMPTY(&_thread_list)) 188 exitNow = 1; 189 190 THREAD_LIST_UNLOCK; 191 DEAD_LIST_UNLOCK; 192 193 if (exitNow) 194 exit(0); 195 196 /* 197 * This function will not return unless we are the last 198 * thread, which we can't be because we've already checked 199 * for that. 200 */ 201 _thr_exit(); 202 203 /* This point should not be reached. */ 204 PANIC("Dead thread has resumed"); 205 } 206 207 /* 208 * Note: this function must be called with the dead thread list 209 * locked. 210 */ 211 static void 212 deadlist_free_threads() 213 { 214 struct pthread *ptd, *ptdTemp; 215 216 TAILQ_FOREACH_SAFE(ptd, &_dead_list, dle, ptdTemp) { 217 /* Don't destroy the initial thread or non-detached threads. */ 218 if (ptd == _thread_initial || 219 (ptd->attr.flags & PTHREAD_DETACHED) == 0) 220 continue; 221 TAILQ_REMOVE(&_dead_list, ptd, dle); 222 deadlist_free_onethread(ptd); 223 } 224 } 225 226 void 227 deadlist_free_onethread(struct pthread *ptd) 228 { 229 230 if (ptd->attr.stackaddr_attr == NULL && ptd->stack != NULL) { 231 STACK_LOCK; 232 _thread_stack_free(ptd->stack, ptd->attr.stacksize_attr, 233 ptd->attr.guardsize_attr); 234 STACK_UNLOCK; 235 } 236 _retire_thread(ptd->arch_id); 237 free(ptd); 238 } 239