thr_sig.c revision 22315 
1/*
2 * Copyright (c) 1995 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 <signal.h>
34#include <fcntl.h>
35#include <unistd.h>
36#include <errno.h>
37#ifdef _THREAD_SAFE
38#include <pthread.h>
39#include "pthread_private.h"
40
41void
42_thread_sig_handler(int sig, int code, struct sigcontext * scp)
43{
44	char            c;
45	int             i;
46	pthread_t       pthread;
47
48	/*
49	 * Check if the pthread kernel has unblocked signals (or is about to)
50	 * and was on its way into a _thread_sys_select when the current
51	 * signal interrupted it:
52	 */
53	if (_thread_kern_in_select) {
54		/* Cast the signal number to a character variable: */
55		c = sig;
56
57		/*
58		 * Write the signal number to the kernel pipe so that it will
59		 * be ready to read when this signal handler returns. This
60		 * means that the _thread_sys_select call will complete
61		 * immediately.
62		 */
63		if (_thread_sys_write(_thread_kern_pipe[1], &c, 1) != 1) {
64		}
65	}
66	/* Check if the signal requires a dump of thread information: */
67	if (sig == SIGINFO) {
68		/* Dump thread information to file: */
69		_thread_dump_info();
70	} else {
71		/* Handle depending on signal type: */
72		switch (sig) {
73		/* Interval timer used for timeslicing: */
74		case SIGVTALRM:
75			/*
76			 * Don't add the signal to any thread.  Just want to
77			 * call the scheduler:
78			 */
79			break;
80
81		/* Child termination: */
82		case SIGCHLD:
83			/*
84			 * Enter a loop to process each thread in the linked
85			 * list:
86			 */
87			for (pthread = _thread_link_list; pthread != NULL;
88			     pthread = pthread->nxt) {
89				/*
90				 * Add the signal to the set of pending
91				 * signals:
92				 */
93				pthread->sigpend[sig] += 1;
94				if (pthread->state == PS_WAIT_WAIT) {
95					/* Reset the error: */
96					/* There should be another flag so that this is not required! ### */
97					_thread_seterrno(pthread, 0);
98
99					/* Change the state of the thread to run: */
100					PTHREAD_NEW_STATE(pthread,PS_RUNNING);
101				}
102			}
103
104			/*
105			 * Go through the file list and set all files
106			 * to non-blocking again in case the child
107			 * set some of them to block. Sigh.
108			 */
109			for (i = 0; i < _thread_dtablesize; i++) {
110				/* Check if this file is used: */
111				if (_thread_fd_table[i] != NULL) {
112					/* Set the file descriptor to non-blocking: */
113					_thread_sys_fcntl(i, F_SETFL, _thread_fd_table[i]->flags | O_NONBLOCK);
114				}
115			}
116			break;
117
118		/* Signals specific to the running thread: */
119		case SIGBUS:
120		case SIGEMT:
121		case SIGFPE:
122		case SIGILL:
123		case SIGPIPE:
124		case SIGSEGV:
125		case SIGSYS:
126			/* Add the signal to the set of pending signals: */
127			_thread_run->sigpend[sig] += 1;
128			break;
129
130		/* Signals to send to all threads: */
131		default:
132			/*
133			 * Enter a loop to process each thread in the linked
134			 * list:
135			 */
136			for (pthread = _thread_link_list; pthread != NULL;
137			     pthread = pthread->nxt) {
138				/*
139				 * Add the signal to the set of pending
140				 * signals:
141				 */
142				pthread->sigpend[sig] += 1;
143			}
144			break;
145		}
146
147		/* Check if the kernel is not locked: */
148		if (_thread_run != &_thread_kern_thread) {
149			/*
150			 * Schedule the next thread. This function is not
151			 * expected to return because it will do a longjmp
152			 * instead.
153			 */
154			_thread_kern_sched(scp);
155
156			/*
157			 * This point should not be reached, so abort the
158			 * process:
159			 */
160			PANIC("Returned to signal function from scheduler");
161		}
162	}
163
164	/* Returns nothing. */
165	return;
166}
167#endif
168