2 * Copyright (c) 1997 John Birrell <jb@cimlogic.com.au>.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
32 * $FreeBSD: src/lib/libc_r/uthread/uthread_sigwait.c,v 1.13.2.5 2002/10/22 14:44:03 fjoe Exp $
35 #include <sys/param.h>
36 #include <sys/signalvar.h>
39 #include "pthread_private.h"
42 sigwait(const sigset_t *set, int *sig)
44 struct pthread *curthread = _get_curthread();
47 sigset_t tempset, waitset;
50 _thread_enter_cancellation_point();
52 * Specify the thread kernel signal handler.
54 act.sa_handler = (void (*) ()) _thread_sig_handler;
55 act.sa_flags = SA_SIGINFO | SA_RESTART;
56 /* Ensure the signal handler cannot be interrupted by other signals: */
57 sigfillset(&act.sa_mask);
60 * Initialize the set of signals that will be waited on:
64 /* These signals can't be waited on. */
65 sigdelset(&waitset, SIGKILL);
66 sigdelset(&waitset, SIGSTOP);
67 sigdelset(&waitset, _SCHED_SIGNAL);
68 sigdelset(&waitset, SIGCHLD);
69 sigdelset(&waitset, SIGINFO);
71 /* Check to see if a pending signal is in the wait mask. */
72 tempset = curthread->sigpend;
73 SIGSETOR(tempset, _process_sigpending);
74 SIGSETAND(tempset, waitset);
75 if (SIGNOTEMPTY(tempset)) {
76 /* Enter a loop to find a pending signal: */
77 for (i = 1; i < NSIG; i++) {
78 if (sigismember (&tempset, i))
82 /* Clear the pending signal: */
83 if (sigismember(&curthread->sigpend,i))
84 sigdelset(&curthread->sigpend,i);
86 sigdelset(&_process_sigpending,i);
88 /* Return the signal number to the caller: */
91 _thread_leave_cancellation_point();
96 * Access the _thread_dfl_count array under the protection of signal
99 _thread_kern_sig_defer();
102 * Enter a loop to find the signals that are SIG_DFL. For
103 * these signals we must install a dummy signal handler in
104 * order for the kernel to pass them in to us. POSIX says
105 * that the _application_ must explicitly install a dummy
106 * handler for signals that are SIG_IGN in order to sigwait
107 * on them. Note that SIG_IGN signals are left in the
108 * mask because a subsequent sigaction could enable an
111 sigemptyset(&tempset);
112 for (i = 1; i < NSIG; i++) {
113 if (sigismember(&waitset, i) &&
114 (_thread_sigact[i - 1].sa_handler == SIG_DFL)) {
115 _thread_dfl_count[i]++;
116 sigaddset(&tempset, i);
117 if (_thread_dfl_count[i] == 1) {
118 if (__sys_sigaction(i,&act,NULL) != 0)
123 /* Done accessing _thread_dfl_count for now. */
124 _thread_kern_sig_undefer();
128 * Save the wait signal mask. The wait signal
129 * mask is independent of the threads signal mask
130 * and requires separate storage.
132 curthread->data.sigwait = &waitset;
134 /* Wait for a signal: */
135 _thread_kern_sched_state(PS_SIGWAIT, __FILE__, __LINE__);
137 /* Return the signal number to the caller: */
138 *sig = curthread->signo;
141 * Probably unnecessary, but since it's in a union struct
142 * we don't know how it could be used in the future.
144 curthread->data.sigwait = NULL;
148 * Access the _thread_dfl_count array under the protection of signal
151 _thread_kern_sig_defer();
153 /* Restore the sigactions: */
154 act.sa_handler = SIG_DFL;
155 for (i = 1; i < NSIG; i++) {
156 if (sigismember(&tempset, i)) {
157 _thread_dfl_count[i]--;
158 if ((_thread_sigact[i - 1].sa_handler == SIG_DFL) &&
159 (_thread_dfl_count[i] == 0)) {
160 if (__sys_sigaction(i,&act,NULL) != 0)
165 /* Done accessing _thread_dfl_count. */
166 _thread_kern_sig_undefer();
168 _thread_leave_cancellation_point();
170 /* Return the completion status: */