thr_kill.c revision 50476 
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 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: head/lib/libkse/thread/thr_kill.c 50476 1999-08-28 00:22:10Z peter $
33 */
34#include <errno.h>
35#include <signal.h>
36#ifdef _THREAD_SAFE
37#include <pthread.h>
38#include "pthread_private.h"
39
40int
41pthread_kill(pthread_t pthread, int sig)
42{
43	int ret;
44
45	/* Check for invalid signal numbers: */
46	if (sig < 0 || sig >= NSIG)
47		/* Invalid signal: */
48		ret = EINVAL;
49
50	/*
51	 * Ensure the thread is in the list of active threads, and the
52	 * signal is valid (signal 0 specifies error checking only) and
53	 * not being ignored:
54	 */
55	else if (((ret = _find_thread(pthread)) == 0) && (sig > 0) &&
56	    (_thread_sigact[sig - 1].sa_handler != SIG_IGN)) {
57		/*
58		 * Defer signals to protect the scheduling queues from
59		 * access by the signal handler:
60		 */
61		_thread_kern_sig_defer();
62
63		switch (pthread->state) {
64		case PS_SIGSUSPEND:
65			/*
66			 * Only wake up the thread if the signal is unblocked
67			 * and there is a handler installed for the signal.
68			 */
69			if (!sigismember(&pthread->sigmask, sig) &&
70			    _thread_sigact[sig - 1].sa_handler != SIG_DFL) {
71				/* Change the state of the thread to run: */
72				PTHREAD_NEW_STATE(pthread,PS_RUNNING);
73
74				/* Return the signal number: */
75				pthread->signo = sig;
76			}
77			/* Increment the pending signal count: */
78			sigaddset(&pthread->sigpend,sig);
79			break;
80
81		case PS_SIGWAIT:
82			/* Wake up the thread if the signal is blocked. */
83			if (sigismember(pthread->data.sigwait, sig)) {
84				/* Change the state of the thread to run: */
85				PTHREAD_NEW_STATE(pthread,PS_RUNNING);
86
87				/* Return the signal number: */
88				pthread->signo = sig;
89			} else
90				/* Increment the pending signal count. */
91				sigaddset(&pthread->sigpend,sig);
92			break;
93
94		case PS_FDR_WAIT:
95		case PS_FDW_WAIT:
96		case PS_POLL_WAIT:
97		case PS_SLEEP_WAIT:
98		case PS_SELECT_WAIT:
99			if (!sigismember(&pthread->sigmask, sig) &&
100			    (_thread_sigact[sig - 1].sa_handler != SIG_IGN)) {
101				/* Flag the operation as interrupted: */
102				pthread->interrupted = 1;
103
104				if (pthread->flags & PTHREAD_FLAGS_IN_WORKQ)
105					PTHREAD_WORKQ_REMOVE(pthread);
106
107				/* Change the state of the thread to run: */
108				PTHREAD_NEW_STATE(pthread,PS_RUNNING);
109
110				/* Return the signal number: */
111				pthread->signo = sig;
112			} else {
113				/* Increment the pending signal count: */
114				sigaddset(&pthread->sigpend,sig);
115			}
116			break;
117
118		default:
119			/* Increment the pending signal count: */
120			sigaddset(&pthread->sigpend,sig);
121			break;
122		}
123
124
125		/*
126		 * Check that a custom handler is installed
127		 * and if the signal is not blocked:
128		 */
129		if (_thread_sigact[sig - 1].sa_handler != SIG_DFL &&
130		    _thread_sigact[sig - 1].sa_handler != SIG_IGN &&
131		    sigismember(&pthread->sigpend, sig) &&
132		    !sigismember(&pthread->sigmask, sig)) {
133			pthread_t pthread_saved = _thread_run;
134
135			/* Current thread inside critical region? */
136			if (_thread_run->sig_defer_count > 0)
137				pthread->sig_defer_count++;
138
139			_thread_run = pthread;
140
141			/* Clear the pending signal: */
142			sigdelset(&pthread->sigpend, sig);
143
144			/*
145			 * Dispatch the signal via the custom signal
146			 * handler:
147			 */
148			(*(_thread_sigact[sig - 1].sa_handler))(sig);
149
150			_thread_run = pthread_saved;
151
152			if (_thread_run->sig_defer_count > 0)
153				pthread->sig_defer_count--;
154		}
155
156		/*
157		 * Undefer and handle pending signals, yielding if
158		 * necessary:
159		 */
160		_thread_kern_sig_undefer();
161	}
162
163	/* Return the completion status: */
164	return (ret);
165}
166#endif
167