thr_join.c revision 35008 
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 <errno.h>
34#ifdef _THREAD_SAFE
35#include <pthread.h>
36#include "pthread_private.h"
37
38int
39pthread_join(pthread_t pthread, void **thread_return)
40{
41	int             rval = 0;
42	int             status;
43	pthread_t	pthread1;
44
45	/* Check if the caller has specified an invalid thread: */
46	if (pthread == NULL || pthread->magic != PTHREAD_MAGIC)
47		/* Invalid thread: */
48		return(EINVAL);
49
50	/* Check if the caller has specified itself: */
51	if (pthread == _thread_run)
52		/* Avoid a deadlock condition: */
53		return(EDEADLK);
54
55	/* Block signals: */
56	_thread_kern_sig_block(&status);
57
58	/* Point to the first thread in the list: */
59	pthread1 = _thread_link_list;
60
61	/* Search for the thread to join to: */
62	while (pthread1 != NULL && pthread1 != pthread) {
63		/* Point to the next thread: */
64		pthread1 = pthread1->nxt;
65	}
66
67	if (pthread1 == NULL) {
68		/* Point to the first thread in the dead thread list: */
69		pthread1 = _thread_dead;
70
71		/* Search for the thread to join to: */
72		while (pthread1 != NULL && pthread1 != pthread) {
73			/* Point to the next thread: */
74			pthread1 = pthread1->nxt;
75		}
76	}
77
78	if (pthread1 == NULL) {
79		/* Return an error: */
80		rval = ESRCH;
81
82	/* Check if this thread has been detached: */
83	} else if ((pthread->attr.flags & PTHREAD_DETACHED) != 0) {
84		/* Return an error: */
85		rval = ESRCH;
86	}
87	/* Check if the thread is not dead: */
88	else if (pthread->state != PS_DEAD) {
89		/* Add the running thread to the join queue: */
90		_thread_queue_enq(&(pthread->join_queue), _thread_run);
91
92		/* Schedule the next thread: */
93		_thread_kern_sched_state(PS_JOIN, __FILE__, __LINE__);
94
95		/* Block signals again: */
96		_thread_kern_sig_block(NULL);
97
98		/* Check if the thread is not detached: */
99		if ((pthread->attr.flags & PTHREAD_DETACHED) == 0) {
100			/* Check if the return value is required: */
101			if (thread_return) {
102				/* Return the thread's return value: */
103				*thread_return = pthread->ret;
104			}
105		} else {
106			/* Return an error: */
107			rval = ESRCH;
108		}
109	} else {
110		/* Check if the return value is required: */
111		if (thread_return != NULL) {
112			/* Return the thread's return value: */
113			*thread_return = pthread->ret;
114		}
115	}
116
117	/* Unblock signals: */
118	_thread_kern_sig_unblock(status);
119
120	/* Return the completion status: */
121	return (rval);
122}
123#endif
124