1 /* $OpenBSD: rthread_fork.c,v 1.21 2017/07/30 19:48:30 tedu 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 #ifndef NO_PIC 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 <tib.h> 43 #include <unistd.h> 44 45 #include "thread_private.h" /* in libc/include */ 46 47 #include "rthread.h" 48 #include "rthread_cb.h" 49 50 /* make {fork,vfork,getthrid} call _thread_sys_{fork,vfork,getthrid} */ 51 REDIRECT_SYSCALL(fork); 52 REDIRECT_SYSCALL(vfork); 53 REDIRECT_SYSCALL(getthrid); 54 55 static pid_t 56 _dofork(pid_t (*sys_fork)(void)) 57 { 58 pthread_t me; 59 pid_t newid; 60 int i; 61 extern int _post_threaded; 62 63 if (!_threads_ready) 64 return sys_fork(); 65 66 me = pthread_self(); 67 68 /* 69 * Protect important libc/ld.so critical areas across the fork call. 70 * dlclose() will grab the atexit lock via __cxa_finalize() so lock 71 * the dl_lock first. malloc()/free() can use arc4random(), so lock 72 * malloc_lock before arc4_lock 73 */ 74 75 #ifndef NO_PIC 76 if (_DYNAMIC) 77 _rthread_dl_lock(0); 78 #endif 79 80 _thread_atexit_lock(); 81 for (i = 0; i < _MALLOC_MUTEXES; i++) 82 _thread_malloc_lock(i); 83 _thread_arc4_lock(); 84 85 newid = sys_fork(); 86 87 _thread_arc4_unlock(); 88 if (newid == 0) 89 _thread_malloc_reinit(); 90 else 91 for (i = 0; i < _MALLOC_MUTEXES; i++) 92 _thread_malloc_unlock(i); 93 _thread_atexit_unlock(); 94 95 if (newid == 0) { 96 struct tib *tib = me->tib; 97 #ifndef NO_PIC 98 /* reinitialize the lock in the child */ 99 if (_DYNAMIC) 100 _rthread_dl_lock(2); 101 #endif 102 /* update this thread's structure */ 103 tib->tib_tid = getthrid(); 104 me->donesem.lock = _SPINLOCK_UNLOCKED; 105 me->flags_lock = _SPINLOCK_UNLOCKED; 106 107 /* reinit the thread list */ 108 LIST_INIT(&_thread_list); 109 LIST_INSERT_HEAD(&_thread_list, me, threads); 110 _thread_lock = _SPINLOCK_UNLOCKED; 111 112 /* single threaded now */ 113 __isthreaded = 0; 114 _post_threaded = 0; /* notyet... */ 115 } 116 #ifndef NO_PIC 117 else if (_DYNAMIC) 118 _rthread_dl_lock(1); 119 #endif 120 return newid; 121 } 122 123 pid_t 124 _thread_fork(void) 125 { 126 return _dofork(&fork); 127 } 128 129 pid_t 130 _thread_vfork(void) 131 { 132 return _dofork(&vfork); 133 } 134