1 /* $OpenBSD: rthread_fork.c,v 1.16 2016/04/02 19:00:51 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 #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 <unistd.h> 43 44 #include "thread_private.h" /* in libc/include */ 45 46 #include "rthread.h" 47 48 REDIRECT_SYSCALL(getthrid); 49 50 pid_t _thread_sys_fork(void); 51 pid_t _thread_sys_vfork(void); 52 pid_t _dofork(int); 53 54 pid_t 55 _dofork(int is_vfork) 56 { 57 pthread_t me; 58 pid_t (*sys_fork)(void); 59 pid_t newid; 60 61 sys_fork = is_vfork ? &_thread_sys_vfork : &_thread_sys_fork; 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 _thread_malloc_lock(); 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 _thread_malloc_unlock(); 91 _thread_atexit_unlock(); 92 93 if (newid == 0) { 94 #ifndef NO_PIC 95 /* reinitialize the lock in the child */ 96 if (_DYNAMIC) 97 _rthread_dl_lock(2); 98 #endif 99 /* update this thread's structure */ 100 me->tid = getthrid(); 101 me->donesem.lock = _SPINLOCK_UNLOCKED_ASSIGN; 102 me->flags &= ~THREAD_DETACHED; 103 me->flags_lock = _SPINLOCK_UNLOCKED_ASSIGN; 104 105 /* this thread is the initial thread for the new process */ 106 me->flags |= THREAD_ORIGINAL; 107 108 /* reinit the thread list */ 109 LIST_INIT(&_thread_list); 110 LIST_INSERT_HEAD(&_thread_list, me, threads); 111 _thread_lock = _SPINLOCK_UNLOCKED_ASSIGN; 112 113 /* single threaded now */ 114 __isthreaded = 0; 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(0); 127 } 128 129 pid_t 130 vfork(void) 131 { 132 return _dofork(1); 133 } 134