1 /* $OpenBSD: rthread_fork.c,v 1.19 2016/09/04 10:13:35 akfaew 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 62 if (!_threads_ready) 63 return sys_fork(); 64 65 me = pthread_self(); 66 67 /* 68 * Protect important libc/ld.so critical areas across the fork call. 69 * dlclose() will grab the atexit lock via __cxa_finalize() so lock 70 * the dl_lock first. malloc()/free() can use arc4random(), so lock 71 * malloc_lock before arc4_lock 72 */ 73 74 #ifndef NO_PIC 75 if (_DYNAMIC) 76 _rthread_dl_lock(0); 77 #endif 78 79 _thread_atexit_lock(); 80 for (i = 0; i < _MALLOC_MUTEXES; i++) 81 _thread_malloc_lock(i); 82 _thread_arc4_lock(); 83 84 newid = sys_fork(); 85 86 _thread_arc4_unlock(); 87 if (newid == 0) 88 _thread_malloc_reinit(); 89 else 90 for (i = 0; i < _MALLOC_MUTEXES; i++) 91 _thread_malloc_unlock(i); 92 _thread_atexit_unlock(); 93 94 if (newid == 0) { 95 struct tib *tib = me->tib; 96 #ifndef NO_PIC 97 /* reinitialize the lock in the child */ 98 if (_DYNAMIC) 99 _rthread_dl_lock(2); 100 #endif 101 /* update this thread's structure */ 102 tib->tib_tid = getthrid(); 103 me->donesem.lock = _SPINLOCK_UNLOCKED; 104 me->flags_lock = _SPINLOCK_UNLOCKED; 105 106 /* reinit the thread list */ 107 LIST_INIT(&_thread_list); 108 LIST_INSERT_HEAD(&_thread_list, me, threads); 109 _thread_lock = _SPINLOCK_UNLOCKED; 110 111 /* single threaded now */ 112 __isthreaded = 0; 113 } 114 #ifndef NO_PIC 115 else if (_DYNAMIC) 116 _rthread_dl_lock(1); 117 #endif 118 return newid; 119 } 120 121 pid_t 122 _thread_fork(void) 123 { 124 return _dofork(&fork); 125 } 126 127 pid_t 128 _thread_vfork(void) 129 { 130 return _dofork(&vfork); 131 } 132