xref: /freebsd/lib/libthr/thread/thr_resume_np.c (revision 031beb4e239bfce798af17f5fe8dba8bcaf13d99)
1 /*-
2  * SPDX-License-Identifier: BSD-3-Clause
3  *
4  * Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer.
12  * 2. Redistributions in binary form must reproduce the above copyright
13  *    notice, this list of conditions and the following disclaimer in the
14  *    documentation and/or other materials provided with the distribution.
15  * 3. Neither the name of the author nor the names of any co-contributors
16  *    may be used to endorse or promote products derived from this software
17  *    without specific prior written permission.
18  *
19  * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
29  * SUCH DAMAGE.
30  */
31 
32 #include <sys/cdefs.h>
33 #include "namespace.h"
34 #include <errno.h>
35 #include <pthread.h>
36 #include <pthread_np.h>
37 #include "un-namespace.h"
38 
39 #include "thr_private.h"
40 
41 __weak_reference(_pthread_resume_np, pthread_resume_np);
42 __weak_reference(_pthread_resume_all_np, pthread_resume_all_np);
43 
44 static void resume_common(struct pthread *thread);
45 
46 /* Resume a thread: */
47 int
48 _pthread_resume_np(pthread_t thread)
49 {
50 	struct pthread *curthread = _get_curthread();
51 	int ret;
52 
53 	/* Add a reference to the thread: */
54 	if ((ret = _thr_find_thread(curthread, thread, /*include dead*/0)) == 0) {
55 		/* Lock the threads scheduling queue: */
56 		resume_common(thread);
57 		THR_THREAD_UNLOCK(curthread, thread);
58 	}
59 	return (ret);
60 }
61 
62 void
63 _pthread_resume_all_np(void)
64 {
65 	struct pthread *curthread = _get_curthread();
66 	struct pthread *thread;
67 	int old_nocancel;
68 
69 	old_nocancel = curthread->no_cancel;
70 	curthread->no_cancel = 1;
71 	_thr_suspend_all_lock(curthread);
72 	/* Take the thread list lock: */
73 	THREAD_LIST_RDLOCK(curthread);
74 
75 	TAILQ_FOREACH(thread, &_thread_list, tle) {
76 		if (thread != curthread) {
77 			THR_THREAD_LOCK(curthread, thread);
78 			resume_common(thread);
79 			THR_THREAD_UNLOCK(curthread, thread);
80 		}
81 	}
82 
83 	/* Release the thread list lock: */
84 	THREAD_LIST_UNLOCK(curthread);
85 	_thr_suspend_all_unlock(curthread);
86 	curthread->no_cancel = old_nocancel;
87 	_thr_testcancel(curthread);
88 }
89 
90 static void
91 resume_common(struct pthread *thread)
92 {
93 	/* Clear the suspend flag: */
94 	thread->flags &= ~(THR_FLAGS_NEED_SUSPEND | THR_FLAGS_SUSPENDED);
95 	thread->cycle++;
96 	_thr_umtx_wake(&thread->cycle, 1, 0);
97 }
98