1 /* 2 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>. 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the author nor the names of any co-contributors 14 * may be used to endorse or promote products derived from this software 15 * without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 27 * SUCH DAMAGE. 28 * 29 * $FreeBSD$ 30 */ 31 32 #include "namespace.h" 33 #include <errno.h> 34 #include <pthread.h> 35 #include <pthread_np.h> 36 #include "un-namespace.h" 37 38 #include "thr_private.h" 39 40 static int suspend_common(struct pthread *, struct pthread *, 41 int); 42 43 __weak_reference(_pthread_suspend_np, pthread_suspend_np); 44 __weak_reference(_pthread_suspend_all_np, pthread_suspend_all_np); 45 46 /* Suspend a thread: */ 47 int 48 _pthread_suspend_np(pthread_t thread) 49 { 50 struct pthread *curthread = _get_curthread(); 51 int ret; 52 53 /* Suspending the current thread doesn't make sense. */ 54 if (thread == _get_curthread()) 55 ret = EDEADLK; 56 57 /* Add a reference to the thread: */ 58 else if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0)) 59 == 0) { 60 /* Lock the threads scheduling queue: */ 61 THR_THREAD_LOCK(curthread, thread); 62 suspend_common(curthread, thread, 1); 63 /* Unlock the threads scheduling queue: */ 64 THR_THREAD_UNLOCK(curthread, thread); 65 66 /* Don't forget to remove the reference: */ 67 _thr_ref_delete(curthread, thread); 68 } 69 return (ret); 70 } 71 72 void 73 _thr_suspend_all_lock(struct pthread *curthread) 74 { 75 int old; 76 77 THR_LOCK_ACQUIRE(curthread, &_suspend_all_lock); 78 while (_single_thread != NULL) { 79 old = _suspend_all_cycle; 80 _suspend_all_waiters++; 81 THR_LOCK_RELEASE(curthread, &_suspend_all_lock); 82 _thr_umtx_wait_uint(&_suspend_all_cycle, old, NULL, 0); 83 THR_LOCK_ACQUIRE(curthread, &_suspend_all_lock); 84 _suspend_all_waiters--; 85 } 86 _single_thread = curthread; 87 THR_LOCK_RELEASE(curthread, &_suspend_all_lock); 88 } 89 90 void 91 _thr_suspend_all_unlock(struct pthread *curthread) 92 { 93 94 THR_LOCK_ACQUIRE(curthread, &_suspend_all_lock); 95 _single_thread = NULL; 96 if (_suspend_all_waiters != 0) { 97 _suspend_all_cycle++; 98 _thr_umtx_wake(&_suspend_all_cycle, INT_MAX, 0); 99 } 100 THR_LOCK_RELEASE(curthread, &_suspend_all_lock); 101 } 102 103 void 104 _pthread_suspend_all_np(void) 105 { 106 struct pthread *curthread = _get_curthread(); 107 struct pthread *thread; 108 int old_nocancel; 109 int ret; 110 111 old_nocancel = curthread->no_cancel; 112 curthread->no_cancel = 1; 113 _thr_suspend_all_lock(curthread); 114 THREAD_LIST_RDLOCK(curthread); 115 TAILQ_FOREACH(thread, &_thread_list, tle) { 116 if (thread != curthread) { 117 THR_THREAD_LOCK(curthread, thread); 118 if (thread->state != PS_DEAD && 119 !(thread->flags & THR_FLAGS_SUSPENDED)) 120 thread->flags |= THR_FLAGS_NEED_SUSPEND; 121 THR_THREAD_UNLOCK(curthread, thread); 122 } 123 } 124 thr_kill(-1, SIGCANCEL); 125 126 restart: 127 TAILQ_FOREACH(thread, &_thread_list, tle) { 128 if (thread != curthread) { 129 /* First try to suspend the thread without waiting */ 130 THR_THREAD_LOCK(curthread, thread); 131 ret = suspend_common(curthread, thread, 0); 132 if (ret == 0) { 133 THREAD_LIST_UNLOCK(curthread); 134 /* Can not suspend, try to wait */ 135 THR_REF_ADD(curthread, thread); 136 suspend_common(curthread, thread, 1); 137 THR_REF_DEL(curthread, thread); 138 _thr_try_gc(curthread, thread); 139 /* thread lock released */ 140 141 THREAD_LIST_RDLOCK(curthread); 142 /* 143 * Because we were blocked, things may have 144 * been changed, we have to restart the 145 * process. 146 */ 147 goto restart; 148 } 149 THR_THREAD_UNLOCK(curthread, thread); 150 } 151 } 152 THREAD_LIST_UNLOCK(curthread); 153 _thr_suspend_all_unlock(curthread); 154 curthread->no_cancel = old_nocancel; 155 _thr_testcancel(curthread); 156 } 157 158 static int 159 suspend_common(struct pthread *curthread, struct pthread *thread, 160 int waitok) 161 { 162 uint32_t tmp; 163 164 while (thread->state != PS_DEAD && 165 !(thread->flags & THR_FLAGS_SUSPENDED)) { 166 thread->flags |= THR_FLAGS_NEED_SUSPEND; 167 /* Thread is in creation. */ 168 if (thread->tid == TID_TERMINATED) 169 return (1); 170 tmp = thread->cycle; 171 _thr_send_sig(thread, SIGCANCEL); 172 THR_THREAD_UNLOCK(curthread, thread); 173 if (waitok) { 174 _thr_umtx_wait_uint(&thread->cycle, tmp, NULL, 0); 175 THR_THREAD_LOCK(curthread, thread); 176 } else { 177 THR_THREAD_LOCK(curthread, thread); 178 return (0); 179 } 180 } 181 182 return (1); 183 } 184