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. All advertising materials mentioning features or use of this software 14 * must display the following acknowledgement: 15 * This product includes software developed by John Birrell. 16 * 4. Neither the name of the author nor the names of any co-contributors 17 * may be used to endorse or promote products derived from this software 18 * without specific prior written permission. 19 * 20 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND 21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30 * SUCH DAMAGE. 31 * 32 * $FreeBSD$ 33 */ 34 35 #include "namespace.h" 36 #include <errno.h> 37 #include <pthread.h> 38 #include <pthread_np.h> 39 #include "un-namespace.h" 40 41 #include "thr_private.h" 42 43 static int suspend_common(struct pthread *, struct pthread *, 44 int); 45 46 __weak_reference(_pthread_suspend_np, pthread_suspend_np); 47 __weak_reference(_pthread_suspend_all_np, pthread_suspend_all_np); 48 49 /* Suspend a thread: */ 50 int 51 _pthread_suspend_np(pthread_t thread) 52 { 53 struct pthread *curthread = _get_curthread(); 54 int ret; 55 56 /* Suspending the current thread doesn't make sense. */ 57 if (thread == _get_curthread()) 58 ret = EDEADLK; 59 60 /* Add a reference to the thread: */ 61 else if ((ret = _thr_ref_add(curthread, thread, /*include dead*/0)) 62 == 0) { 63 /* Lock the threads scheduling queue: */ 64 THR_THREAD_LOCK(curthread, thread); 65 suspend_common(curthread, thread, 1); 66 /* Unlock the threads scheduling queue: */ 67 THR_THREAD_UNLOCK(curthread, thread); 68 69 /* Don't forget to remove the reference: */ 70 _thr_ref_delete(curthread, thread); 71 } 72 return (ret); 73 } 74 75 void 76 _pthread_suspend_all_np(void) 77 { 78 struct pthread *curthread = _get_curthread(); 79 struct pthread *thread; 80 int ret; 81 82 THREAD_LIST_LOCK(curthread); 83 84 TAILQ_FOREACH(thread, &_thread_list, tle) { 85 if (thread != curthread) { 86 THR_THREAD_LOCK(curthread, thread); 87 if (thread->state != PS_DEAD && 88 !(thread->flags & THR_FLAGS_SUSPENDED)) 89 thread->flags |= THR_FLAGS_NEED_SUSPEND; 90 THR_THREAD_UNLOCK(curthread, thread); 91 } 92 } 93 thr_kill(-1, SIGCANCEL); 94 95 restart: 96 TAILQ_FOREACH(thread, &_thread_list, tle) { 97 if (thread != curthread) { 98 /* First try to suspend the thread without waiting */ 99 THR_THREAD_LOCK(curthread, thread); 100 ret = suspend_common(curthread, thread, 0); 101 if (ret == 0) { 102 /* Can not suspend, try to wait */ 103 thread->refcount++; 104 THREAD_LIST_UNLOCK(curthread); 105 suspend_common(curthread, thread, 1); 106 THR_THREAD_UNLOCK(curthread, thread); 107 THREAD_LIST_LOCK(curthread); 108 _thr_ref_delete_unlocked(curthread, thread); 109 /* 110 * Because we were blocked, things may have 111 * been changed, we have to restart the 112 * process. 113 */ 114 goto restart; 115 } 116 THR_THREAD_UNLOCK(curthread, thread); 117 } 118 } 119 120 THREAD_LIST_UNLOCK(curthread); 121 } 122 123 static int 124 suspend_common(struct pthread *curthread, struct pthread *thread, 125 int waitok) 126 { 127 umtx_t tmp; 128 129 while (thread->state != PS_DEAD && 130 !(thread->flags & THR_FLAGS_SUSPENDED)) { 131 thread->flags |= THR_FLAGS_NEED_SUSPEND; 132 tmp = thread->cycle; 133 THR_THREAD_UNLOCK(curthread, thread); 134 _thr_send_sig(thread, SIGCANCEL); 135 if (waitok) { 136 _thr_umtx_wait(&thread->cycle, tmp, NULL); 137 THR_THREAD_LOCK(curthread, thread); 138 } else { 139 THR_THREAD_LOCK(curthread, thread); 140 return (0); 141 } 142 } 143 144 return (1); 145 } 146