1 /* $OpenBSD: uthread_wait4.c,v 1.7 2001/11/09 00:20:26 marc Exp $ */
2 /*
3 * Copyright (c) 1995-1998 John Birrell <jb@cimlogic.com.au>
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 * notice, this list of conditions and the following disclaimer.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. All advertising materials mentioning features or use of this software
15 * must display the following acknowledgement:
16 * This product includes software developed by John Birrell.
17 * 4. Neither the name of the author nor the names of any co-contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 *
33 * $FreeBSD: uthread_wait4.c,v 1.5 1999/08/28 00:03:53 peter Exp $
34 */
35 #include <errno.h>
36 #include <sys/wait.h>
37 #ifdef _THREAD_SAFE
38 #include <pthread.h>
39 #include "pthread_private.h"
40
41 /*
42 * Note: a thread calling wait4 may have its state changed to waiting
43 * until awakened by a signal. Also note that system(3), for example,
44 * blocks SIGCHLD and calls waitpid (which calls wait4). If the process
45 * started by system(3) doesn't finish before this function is called the
46 * function will never awaken -- system(3) also ignores SIGINT and SIGQUIT.
47 *
48 * Thus always unmask SIGCHLD here.
49 */
50 pid_t
wait4(pid_t pid,int * istat,int options,struct rusage * rusage)51 wait4(pid_t pid, int *istat, int options, struct rusage * rusage)
52 {
53 struct pthread *curthread = _get_curthread();
54 pid_t ret;
55 sigset_t mask, omask;
56
57 /* This is a cancellation point: */
58 _thread_enter_cancellation_point();
59
60 _thread_kern_sig_defer();
61
62 sigemptyset(&mask);
63 sigaddset(&mask, SIGCHLD);
64 sigprocmask(SIG_UNBLOCK, &mask, &omask);
65
66 /* Perform a non-blocking wait4 syscall: */
67 while ((ret = _thread_sys_wait4(pid, istat, options | WNOHANG, rusage)) == 0 && (options & WNOHANG) == 0) {
68 /* Reset the interrupted operation flag: */
69 curthread->interrupted = 0;
70
71 /* Schedule the next thread while this one waits: */
72 _thread_kern_sched_state(PS_WAIT_WAIT, __FILE__, __LINE__);
73
74 /* Check if this call was interrupted by a signal: */
75 if (curthread->interrupted) {
76 errno = EINTR;
77 ret = -1;
78 break;
79 }
80 }
81
82 sigprocmask(SIG_SETMASK, &omask, NULL);
83
84 _thread_kern_sig_undefer();
85
86 /* No longer in a cancellation point: */
87 _thread_leave_cancellation_point();
88
89 return (ret);
90 }
91 #endif
92