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(_thr_atfork, _pthread_atfork); 79 __weak_reference(_thr_atfork, pthread_atfork); 80 81 int 82 _thr_atfork(void (*prepare)(void), void (*parent)(void), 83 void (*child)(void)) 84 { 85 struct pthread *curthread; 86 struct pthread_atfork *af; 87 88 _thr_check_init(); 89 90 if ((af = malloc(sizeof(struct pthread_atfork))) == NULL) 91 return (ENOMEM); 92 93 curthread = _get_curthread(); 94 af->prepare = prepare; 95 af->parent = parent; 96 af->child = child; 97 THR_CRITICAL_ENTER(curthread); 98 _thr_rwl_wrlock(&_thr_atfork_lock); 99 TAILQ_INSERT_TAIL(&_thr_atfork_list, af, qe); 100 _thr_rwl_unlock(&_thr_atfork_lock); 101 THR_CRITICAL_LEAVE(curthread); 102 return (0); 103 } 104 105 void 106 __pthread_cxa_finalize(struct dl_phdr_info *phdr_info) 107 { 108 atfork_head temp_list = TAILQ_HEAD_INITIALIZER(temp_list); 109 struct pthread *curthread; 110 struct pthread_atfork *af, *af1; 111 112 _thr_check_init(); 113 114 curthread = _get_curthread(); 115 THR_CRITICAL_ENTER(curthread); 116 _thr_rwl_wrlock(&_thr_atfork_lock); 117 TAILQ_FOREACH_SAFE(af, &_thr_atfork_list, qe, af1) { 118 if (__elf_phdr_match_addr(phdr_info, af->prepare) || 119 __elf_phdr_match_addr(phdr_info, af->parent) || 120 __elf_phdr_match_addr(phdr_info, af->child)) { 121 TAILQ_REMOVE(&_thr_atfork_list, af, qe); 122 TAILQ_INSERT_TAIL(&temp_list, af, qe); 123 } 124 } 125 _thr_rwl_unlock(&_thr_atfork_lock); 126 THR_CRITICAL_LEAVE(curthread); 127 while ((af = TAILQ_FIRST(&temp_list)) != NULL) { 128 TAILQ_REMOVE(&temp_list, af, qe); 129 free(af); 130 } 131 _thr_tsd_unload(phdr_info); 132 _thr_sigact_unload(phdr_info); 133 } 134 135 __weak_reference(__thr_fork, _fork); 136 137 pid_t 138 __thr_fork(void) 139 { 140 struct pthread *curthread; 141 struct pthread_atfork *af; 142 pid_t ret; 143 int errsave, cancelsave; 144 int was_threaded; 145 int rtld_locks[MAX_RTLD_LOCKS]; 146 147 if (!_thr_is_inited()) 148 return (__sys_fork()); 149 150 curthread = _get_curthread(); 151 cancelsave = curthread->no_cancel; 152 curthread->no_cancel = 1; 153 _thr_rwl_rdlock(&_thr_atfork_lock); 154 155 /* Run down atfork prepare handlers. */ 156 TAILQ_FOREACH_REVERSE(af, &_thr_atfork_list, atfork_head, qe) { 157 if (af->prepare != NULL) 158 af->prepare(); 159 } 160 161 /* 162 * Block all signals until we reach a safe point. 163 */ 164 _thr_signal_block(curthread); 165 _thr_signal_prefork(); 166 167 /* 168 * All bets are off as to what should happen soon if the parent 169 * process was not so kindly as to set up pthread fork hooks to 170 * relinquish all running threads. 171 */ 172 if (_thr_isthreaded() != 0) { 173 was_threaded = 1; 174 __thr_malloc_prefork(curthread); 175 _malloc_prefork(); 176 __thr_pshared_atfork_pre(); 177 _rtld_atfork_pre(rtld_locks); 178 } else { 179 was_threaded = 0; 180 } 181 182 /* 183 * Fork a new process. 184 * There is no easy way to pre-resolve the __sys_fork symbol 185 * without performing the fork. Use the syscall(2) 186 * indirection, the syscall symbol is resolved in 187 * _thr_rtld_init() with side-effect free call. 188 */ 189 ret = syscall(SYS_fork); 190 if (ret == 0) { 191 /* Child process */ 192 errsave = errno; 193 curthread->cancel_pending = 0; 194 curthread->flags &= ~(THR_FLAGS_NEED_SUSPEND|THR_FLAGS_DETACHED); 195 196 /* 197 * Thread list will be reinitialized, and later we call 198 * _libpthread_init(), it will add us back to list. 199 */ 200 curthread->tlflags &= ~TLFLAGS_IN_TDLIST; 201 202 /* before thr_self() */ 203 if (was_threaded) 204 __thr_malloc_postfork(curthread); 205 206 /* child is a new kernel thread. */ 207 thr_self(&curthread->tid); 208 209 /* clear other threads locked us. */ 210 _thr_umutex_init(&curthread->lock); 211 _mutex_fork(curthread); 212 213 _thr_signal_postfork_child(); 214 215 if (was_threaded) { 216 _rtld_atfork_post(rtld_locks); 217 __thr_pshared_atfork_post(); 218 } 219 _thr_setthreaded(0); 220 221 /* reinitalize library. */ 222 _libpthread_init(curthread); 223 224 /* atfork is reinitialized by _libpthread_init()! */ 225 _thr_rwl_rdlock(&_thr_atfork_lock); 226 227 if (was_threaded) { 228 _thr_setthreaded(1); 229 _malloc_postfork(); 230 _thr_setthreaded(0); 231 } 232 233 /* Ready to continue, unblock signals. */ 234 _thr_signal_unblock(curthread); 235 236 /* Run down atfork child handlers. */ 237 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 238 if (af->child != NULL) 239 af->child(); 240 } 241 _thr_rwlock_unlock(&_thr_atfork_lock); 242 curthread->no_cancel = cancelsave; 243 } else { 244 /* Parent process */ 245 errsave = errno; 246 247 _thr_signal_postfork(); 248 249 if (was_threaded) { 250 __thr_malloc_postfork(curthread); 251 _rtld_atfork_post(rtld_locks); 252 __thr_pshared_atfork_post(); 253 _malloc_postfork(); 254 } 255 256 /* Ready to continue, unblock signals. */ 257 _thr_signal_unblock(curthread); 258 259 /* Run down atfork parent handlers. */ 260 TAILQ_FOREACH(af, &_thr_atfork_list, qe) { 261 if (af->parent != NULL) 262 af->parent(); 263 } 264 265 _thr_rwlock_unlock(&_thr_atfork_lock); 266 curthread->no_cancel = cancelsave; 267 /* test async cancel */ 268 if (curthread->cancel_async) 269 _thr_testcancel(curthread); 270 } 271 errno = errsave; 272 273 return (ret); 274 } 275