1 /* $OpenBSD: rthread_fork.c,v 1.12 2015/05/10 18:33:15 guenther Exp $ */ 2 3 /* 4 * Copyright (c) 2008 Kurt Miller <kurt@openbsd.org> 5 * Copyright (c) 2008 Philip Guenther <guenther@openbsd.org> 6 * Copyright (c) 2003 Daniel Eischen <deischen@freebsd.org> 7 * All rights reserved. 8 * 9 * Redistribution and use in source and binary forms, with or without 10 * modification, are permitted provided that the following conditions 11 * are met: 12 * 1. Redistributions of source code must retain the above copyright 13 * notice, this list of conditions and the following disclaimer. 14 * 2. Neither the name of the author nor the names of any co-contributors 15 * may be used to endorse or promote products derived from this software 16 * without specific prior written permission. 17 * 18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 19 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 22 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28 * SUCH DAMAGE. 29 * 30 * $FreeBSD: /repoman/r/ncvs/src/lib/libc_r/uthread/uthread_atfork.c,v 1.1 2004/12/10 03:36:45 grog Exp $ 31 */ 32 33 #if defined(__ELF__) 34 #include <sys/types.h> 35 #include <sys/exec_elf.h> 36 #pragma weak _DYNAMIC 37 #endif 38 39 #include <errno.h> 40 #include <pthread.h> 41 #include <stdlib.h> 42 #include <unistd.h> 43 #include <signal.h> 44 45 #include "thread_private.h" /* in libc/include */ 46 47 #include "rthread.h" 48 49 pid_t _thread_sys_fork(void); 50 pid_t _thread_sys_vfork(void); 51 pid_t _dofork(int); 52 53 pid_t 54 _dofork(int is_vfork) 55 { 56 pthread_t me; 57 pid_t (*sys_fork)(void); 58 pid_t newid; 59 #if defined(__ELF__) 60 sigset_t nmask, omask; 61 #endif 62 63 sys_fork = is_vfork ? &_thread_sys_vfork : &_thread_sys_fork; 64 65 if (!_threads_ready) 66 return sys_fork(); 67 68 me = pthread_self(); 69 70 /* 71 * Protect important libc/ld.so critical areas across the fork call. 72 * dlclose() will grab the atexit lock via __cxa_finalize() so lock 73 * the dl_lock first. malloc()/free() can grab the arc4 lock so lock 74 * malloc_lock first. Finally lock the bind_lock last so that any lazy 75 * binding in the other locking functions can succeed. 76 */ 77 78 #if defined(__ELF__) 79 if (_DYNAMIC) 80 _rthread_dl_lock(0); 81 #endif 82 83 _thread_atexit_lock(); 84 _thread_malloc_lock(); 85 _thread_arc4_lock(); 86 87 #if defined(__ELF__) 88 if (_DYNAMIC) { 89 sigfillset(&nmask); 90 _thread_sys_sigprocmask(SIG_BLOCK, &nmask, &omask); 91 _rthread_bind_lock(0); 92 } 93 #endif 94 95 newid = sys_fork(); 96 97 #if defined(__ELF__) 98 if (_DYNAMIC) { 99 _rthread_bind_lock(1); 100 _thread_sys_sigprocmask(SIG_SETMASK, &omask, NULL); 101 } 102 #endif 103 104 _thread_arc4_unlock(); 105 _thread_malloc_unlock(); 106 _thread_atexit_unlock(); 107 108 if (newid == 0) { 109 #if defined(__ELF__) 110 /* reinitialize the lock in the child */ 111 if (_DYNAMIC) 112 _rthread_dl_lock(2); 113 #endif 114 /* update this thread's structure */ 115 me->tid = getthrid(); 116 me->donesem.lock = _SPINLOCK_UNLOCKED_ASSIGN; 117 me->flags &= ~THREAD_DETACHED; 118 me->flags_lock = _SPINLOCK_UNLOCKED_ASSIGN; 119 120 /* this thread is the initial thread for the new process */ 121 me->flags |= THREAD_ORIGINAL; 122 123 /* reinit the thread list */ 124 LIST_INIT(&_thread_list); 125 LIST_INSERT_HEAD(&_thread_list, me, threads); 126 _thread_lock = _SPINLOCK_UNLOCKED_ASSIGN; 127 128 /* single threaded now */ 129 __isthreaded = 0; 130 } 131 #if defined(__ELF__) 132 else if (_DYNAMIC) 133 _rthread_dl_lock(1); 134 #endif 135 return newid; 136 } 137 138 pid_t 139 _thread_fork(void) 140 { 141 return _dofork(0); 142 } 143 144 pid_t 145 vfork(void) 146 { 147 return _dofork(1); 148 } 149