xref: /titanic_44/usr/src/lib/libc/port/gen/sh_locks.c (revision 7257d1b4d25bfac0c802847390e98a464fd787ac)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 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 "lint.h"
30 #include <mtlib.h>
31 #include <sys/types.h>
32 #include <synch.h>
33 #include <thread.h>
34 #include <pthread.h>
35 #include "libc.h"
36 
37 /*
38  * fork1-safety.
39  * These three routines were used to make some libc interfaces fork1-safe.
40  * With the merge of libthread into libc, almost all libc internal-only
41  * locks are acquired via lmutex_lock() or lrw_rdlock()/lrw_wrlock(),
42  * which makes them automatically fork1-safe (as well as async-signal
43  * safe), so these functions are now used only for the locks that cannot
44  * be used with lmutex_lock or lrw_rdlock()/lrw_wrlock().
45  */
46 
47 extern void atexit_locks(void);
48 extern void atexit_unlocks(void);
49 
50 extern void stdio_locks(void);
51 extern void stdio_unlocks(void);
52 
53 extern void malloc_locks(void);
54 extern void malloc_unlocks(void);
55 
56 static void
libc_prepare_atfork(void)57 libc_prepare_atfork(void)
58 {
59 	atexit_locks();
60 	stdio_locks();
61 	malloc_locks();
62 }
63 
64 static void
libc_child_atfork(void)65 libc_child_atfork(void)
66 {
67 	malloc_unlocks();
68 	stdio_unlocks();
69 	atexit_unlocks();
70 }
71 
72 static void
libc_parent_atfork(void)73 libc_parent_atfork(void)
74 {
75 	malloc_unlocks();
76 	stdio_unlocks();
77 	atexit_unlocks();
78 }
79 
80 /* called from libc_init() */
81 void
atfork_init(void)82 atfork_init(void)
83 {
84 	(void) pthread_atfork(libc_prepare_atfork,
85 	    libc_parent_atfork, libc_child_atfork);
86 }
87