1 /* 2 * Copyright (c) 2005 David Xu <davidxu@freebsd.org> 3 * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org> 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Neither the name of the author nor the names of any co-contributors 12 * may be used to endorse or promote products derived from this software 13 * without specific prior written permission. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25 * SUCH DAMAGE. 26 */ 27 28 /*- 29 * SPDX-License-Identifier: BSD-3-Clause 30 * 31 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au> 32 * All rights reserved. 33 * 34 * Redistribution and use in source and binary forms, with or without 35 * modification, are permitted provided that the following conditions 36 * are met: 37 * 1. Redistributions of source code must retain the above copyright 38 * notice, this list of conditions and the following disclaimer. 39 * 2. Redistributions in binary form must reproduce the above copyright 40 * notice, this list of conditions and the following disclaimer in the 41 * documentation and/or other materials provided with the distribution. 42 * 3. Neither the name of the author nor the names of any co-contributors 43 * may be used to endorse or promote products derived from this software 44 * without specific prior written permission. 45 * 46 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 47 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 48 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 49 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 50 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 51 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 52 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 53 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 54 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 55 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 56 * SUCH DAMAGE. 57 * 58 */ 59 60 #include <sys/cdefs.h> 61 __FBSDID("$FreeBSD$"); 62 63 #include <sys/syscall.h> 64 #include "namespace.h" 65 #include <errno.h> 66 #include <link.h> 67 #include <string.h> 68 #include <stdlib.h> 69 #include <unistd.h> 70 #include <pthread.h> 71 #include <spinlock.h> 72 #include "un-namespace.h" 73 74 #include "libc_private.h" 75 #include "rtld_lock.h" 76 #include "thr_private.h" 77 78 __weak_reference(_pthread_atfork, pthread_atfork); 79 80 int 81 _pthread_atfork(void (*prepare)(void), void (*parent)(void), 82 void (*child)(void)) 83 { 84 struct pthread *curthread; 85 struct pthread_atfork *af; 86 87 _thr_check_init(); 88 89 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 90 return (ENOMEM); 91 92 curthread = _get_curthread(); 93 af->prepare = prepare; 94 af->parent = parent; 95 af->child = child; 96 THR_CRITICAL_ENTER(curthread); 97 _thr_rwl_wrlock(&_thr_atfork_lock); 98 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 99 _thr_rwl_unlock(&_thr_atfork_lock); 100 THR_CRITICAL_LEAVE(curthread); 101 return (0); 102 } 103 104 void 105 __pthread_cxa_finalize(struct dl_phdr_info *phdr_info) 106 { 107 atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list); 108 struct pthread *curthread; 109 struct pthread_atfork *af, *af1; 110 111 _thr_check_init(); 112 113 curthread = _get_curthread(); 114 THR_CRITICAL_ENTER(curthread); 115 _thr_rwl_wrlock(&_thr_atfork_lock); 116 TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) { 117 if (__elf_phdr_match_addr(phdr_info, af->prepare) || 118 __elf_phdr_match_addr(phdr_info, af->parent) || 119 __elf_phdr_match_addr(phdr_info, af->child)) { 120 TAILQ_REMOVE(&_thr_atfork_list, af, qe); 121 TAILQ_INSERT_TAIL(&temp_list, af, qe); 122 } 123 } 124 _thr_rwl_unlock(&_thr_atfork_lock); 125 THR_CRITICAL_LEAVE(curthread); 126 while ((af = TAILQ_FIRST(&temp_list)) != NULL) { 127 TAILQ_REMOVE(&temp_list, af, qe); 128 free(af); 129 } 130 _thr_tsd_unload(phdr_info); 131 _thr_sigact_unload(phdr_info); 132 } 133 134 __weak_reference(__thr_fork, _fork); 135 136 pid_t 137 __thr_fork(void) 138 { 139 struct pthread *curthread; 140 struct pthread_atfork *af; 141 pid_t ret; 142 int errsave, cancelsave; 143 int was_threaded; 144 int rtld_locks[MAX_RTLD_LOCKS]; 145 146 if (!_thr_is_inited()) 147 return (__sys_fork()); 148 149 curthread = _get_curthread(); 150 cancelsave = curthread->no_cancel; 151 curthread->no_cancel = 1; 152 _thr_rwl_rdlock(&_thr_atfork_lock); 153 154 /* Run down atfork prepare handlers. */ 155 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { 156 if (af->prepare != NULL) 157 af->prepare(); 158 } 159 160 /* 161 * Block all signals until we reach a safe point. 162 */ 163 _thr_signal_block(curthread); 164 _thr_signal_prefork(); 165 166 /* 167 * All bets are off as to what should happen soon if the parent 168 * process was not so kindly as to set up pthread fork hooks to 169 * relinquish all running threads. 170 */ 171 if (_thr_isthreaded() != 0) { 172 was_threaded = 1; 173 _malloc_prefork(); 174 __thr_pshared_atfork_pre(); 175 _rtld_atfork_pre(rtld_locks); 176 } else { 177 was_threaded = 0; 178 } 179 180 /* 181 * Fork a new process. 182 * There is no easy way to pre-resolve the __sys_fork symbol 183 * without performing the fork. Use the syscall(2) 184 * indirection, the syscall symbol is resolved in 185 * _thr_rtld_init() with side-effect free call. 186 */ 187 ret = syscall(SYS_fork); 188 if (ret == 0) { 189 /* Child process */ 190 errsave = errno; 191 curthread->cancel_pending = 0; 192 curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED); 193 194 /* 195 * Thread list will be reinitialized, and later we call 196 * _libpthread_init(), it will add us back to list. 197 */ 198 curthread->tlflags &= ~TLFLAGS_IN_TDLIST; 199 200 /* child is a new kernel thread. */ 201 thr_self(&curthread->tid); 202 203 /* clear other threads locked us. */ 204 _thr_umutex_init(&curthread->lock); 205 _mutex_fork(curthread); 206 207 _thr_signal_postfork_child(); 208 209 if (was_threaded) { 210 _rtld_atfork_post(rtld_locks); 211 __thr_pshared_atfork_post(); 212 } 213 _thr_setthreaded(0); 214 215 /* reinitalize library. */ 216 _libpthread_init(curthread); 217 218 /* atfork is reinitialized by _libpthread_init()! */ 219 _thr_rwl_rdlock(&_thr_atfork_lock); 220 221 if (was_threaded) { 222 __isthreaded = 1; 223 _malloc_postfork(); 224 __isthreaded = 0; 225 } 226 227 /* Ready to continue, unblock signals. */ 228 _thr_signal_unblock(curthread); 229 230 /* Run down atfork child handlers. */ 231 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 232 if (af->child != NULL) 233 af->child(); 234 } 235 _thr_rwlock_unlock(&_thr_atfork_lock); 236 curthread->no_cancel = cancelsave; 237 } else { 238 /* Parent process */ 239 errsave = errno; 240 241 _thr_signal_postfork(); 242 243 if (was_threaded) { 244 _rtld_atfork_post(rtld_locks); 245 __thr_pshared_atfork_post(); 246 _malloc_postfork(); 247 } 248 249 /* Ready to continue, unblock signals. */ 250 _thr_signal_unblock(curthread); 251 252 /* Run down atfork parent handlers. */ 253 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 254 if (af->parent != NULL) 255 af->parent(); 256 } 257 258 _thr_rwlock_unlock(&_thr_atfork_lock); 259 curthread->no_cancel = cancelsave; 260 /* test async cancel */ 261 if (curthread->cancel_async) 262 _thr_testcancel(curthread); 263 } 264 errno = errsave; 265 266 return (ret); 267 } 268