thr_kill.c revision 44963 
1/*
2 * Copyright (c) 1997 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 REGENTS 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 */
33#include <errno.h>
34#include <signal.h>
35#ifdef _THREAD_SAFE
36#include <pthread.h>
37#include "pthread_private.h"
38
39int
40pthread_kill(pthread_t pthread, int sig)
41{
42	int ret;
43
44	/* Check for invalid signal numbers: */
45	if (sig < 0 || sig >= NSIG)
46		/* Invalid signal: */
47		ret = EINVAL;
48
49	/* Ignored signals get dropped on the floor. */
50	else if (_thread_sigact[sig - 1].sa_handler == SIG_IGN)
51		ret = 0;
52
53	/* Find the thread in the list of active threads: */
54	else if ((ret = _find_thread(pthread)) == 0) {
55		/*
56		 * Guard against preemption by a scheduling signal.
57		 * A change of thread state modifies the waiting
58		 * and priority queues.
59		 */
60		_thread_kern_sched_defer();
61
62		switch (pthread->state) {
63		case PS_SIGSUSPEND:
64			/*
65			 * Only wake up the thread if the signal is unblocked
66			 * and there is a handler installed for the signal.
67			 */
68			if (!sigismember(&pthread->sigmask, sig) &&
69			    _thread_sigact[sig - 1].sa_handler != SIG_DFL) {
70				/* Change the state of the thread to run: */
71				PTHREAD_NEW_STATE(pthread,PS_RUNNING);
72
73				/* Return the signal number: */
74				pthread->signo = sig;
75			}
76			/* Increment the pending signal count: */
77			sigaddset(&pthread->sigpend,sig);
78			break;
79
80		case PS_SIGWAIT:
81			/* Wake up the thread if the signal is blocked. */
82			if (sigismember(pthread->data.sigwait, sig)) {
83				/* Change the state of the thread to run: */
84				PTHREAD_NEW_STATE(pthread,PS_RUNNING);
85
86				/* Return the signal number: */
87				pthread->signo = sig;
88			} else
89				/* Increment the pending signal count. */
90				sigaddset(&pthread->sigpend,sig);
91			break;
92
93		case PS_SELECT_WAIT:
94		case PS_FDR_WAIT:
95		case PS_FDW_WAIT:
96		case PS_SLEEP_WAIT:
97			if (!sigismember(&pthread->sigmask, sig) &&
98			    (_thread_sigact[sig - 1].sa_handler != SIG_IGN)) {
99				/* Flag the operation as interrupted: */
100				pthread->interrupted = 1;
101
102				/* Change the state of the thread to run: */
103				PTHREAD_NEW_STATE(pthread,PS_RUNNING);
104
105				/* Return the signal number: */
106				pthread->signo = sig;
107			} else {
108				/* Increment the pending signal count: */
109				sigaddset(&pthread->sigpend,sig);
110			}
111			break;
112
113		default:
114			/* Increment the pending signal count: */
115			sigaddset(&pthread->sigpend,sig);
116			break;
117		}
118
119		/*
120		 * Reenable preemption and yield if a scheduling signal
121		 * occurred while in the critical region.
122		 */
123		_thread_kern_sched_undefer();
124	}
125
126	/* Return the completion status: */
127	return (ret);
128}
129#endif
130