xref: /illumos-gate/usr/src/lib/libc/port/gen/sh_locks.c (revision 4de2612967d06c4fdbf524a62556a1e8118a006f)
1 /*
2  * CDDL HEADER START
3  *
4  * The contents of this file are subject to the terms of the
5  * Common Development and Distribution License, Version 1.0 only
6  * (the "License").  You may not use this file except in compliance
7  * with the License.
8  *
9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
10  * or http://www.opensolaris.org/os/licensing.
11  * See the License for the specific language governing permissions
12  * and limitations under the License.
13  *
14  * When distributing Covered Code, include this CDDL HEADER in each
15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
16  * If applicable, add the following below this CDDL HEADER, with the
17  * fields enclosed by brackets "[]" replaced with your own identifying
18  * information: Portions Copyright [yyyy] [name of copyright owner]
19  *
20  * CDDL HEADER END
21  */
22 /*
23  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 #pragma ident	"%Z%%M%	%I%	%E% SMI"
28 
29 #include "synonyms.h"
30 #include <mtlib.h>
31 #include <sys/types.h>
32 #include <synch.h>
33 #include <thread.h>
34 #include "libc.h"
35 
36 /*
37  * fork1-safety.
38  * These three routines were used to make some libc interfaces fork1-safe.
39  * With the merge of libthread into libc, almost all libc internal-only
40  * locks are acquired via lmutex_lock() or lrw_rdlock()/lrw_wrlock(),
41  * which makes them automatically fork1-safe (as well as async-signal
42  * safe), so these functions are now used only for the locks that cannot
43  * be used with lmutex_lock or lrw_rdlock()/lrw_wrlock().
44  */
45 
46 extern void atexit_locks(void);
47 extern void atexit_unlocks(void);
48 
49 extern void stdio_locks(void);
50 extern void stdio_unlocks(void);
51 
52 static void
53 libc_prepare_atfork(void)
54 {
55 	atexit_locks();
56 	stdio_locks();
57 }
58 
59 static void
60 libc_child_atfork(void)
61 {
62 	stdio_unlocks();
63 	atexit_unlocks();
64 }
65 
66 static void
67 libc_parent_atfork(void)
68 {
69 	stdio_unlocks();
70 	atexit_unlocks();
71 }
72 
73 /* called from libc_init() */
74 void
75 atfork_init(void)
76 {
77 	/* same as pthread_atfork() but private to libc */
78 	extern int _private_pthread_atfork(void (*)(void),
79 		void (*)(void), void (*)(void));
80 
81 	(void) _private_pthread_atfork(libc_prepare_atfork,
82 		libc_parent_atfork, libc_child_atfork);
83 }
84