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 _pthread_suspend_all_np(void) 74 { 75 struct pthread *curthread = _get_curthread(); 76 struct pthread *thread; 77 int ret; 78 79 THREAD_LIST_LOCK(curthread); 80 81 TAILQ_FOREACH(thread, &_thread_list, tle) { 82 if (thread != curthread) { 83 THR_THREAD_LOCK(curthread, thread); 84 if (thread->state != PS_DEAD && 85 !(thread->flags & THR_FLAGS_SUSPENDED)) 86 thread->flags |= THR_FLAGS_NEED_SUSPEND; 87 THR_THREAD_UNLOCK(curthread, thread); 88 } 89 } 90 thr_kill(-1, SIGCANCEL); 91 92 restart: 93 TAILQ_FOREACH(thread, &_thread_list, tle) { 94 if (thread != curthread) { 95 /* First try to suspend the thread without waiting */ 96 THR_THREAD_LOCK(curthread, thread); 97 ret = suspend_common(curthread, thread, 0); 98 if (ret == 0) { 99 /* Can not suspend, try to wait */ 100 thread->refcount++; 101 THREAD_LIST_UNLOCK(curthread); 102 suspend_common(curthread, thread, 1); 103 THR_THREAD_UNLOCK(curthread, thread); 104 THREAD_LIST_LOCK(curthread); 105 _thr_ref_delete_unlocked(curthread, thread); 106 /* 107 * Because we were blocked, things may have 108 * been changed, we have to restart the 109 * process. 110 */ 111 goto restart; 112 } 113 THR_THREAD_UNLOCK(curthread, thread); 114 } 115 } 116 117 THREAD_LIST_UNLOCK(curthread); 118 } 119 120 static int 121 suspend_common(struct pthread *curthread, struct pthread *thread, 122 int waitok) 123 { 124 umtx_t tmp; 125 126 while (thread->state != PS_DEAD && 127 !(thread->flags & THR_FLAGS_SUSPENDED)) { 128 thread->flags |= THR_FLAGS_NEED_SUSPEND; 129 tmp = thread->cycle; 130 THR_THREAD_UNLOCK(curthread, thread); 131 _thr_send_sig(thread, SIGCANCEL); 132 if (waitok) { 133 _thr_umtx_wait(&thread->cycle, tmp, NULL); 134 THR_THREAD_LOCK(curthread, thread); 135 } else { 136 THR_THREAD_LOCK(curthread, thread); 137 return (0); 138 } 139 } 140 141 return (1); 142 } 143