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flockfile.c revision 1.3 
      1 /*	$NetBSD: flockfile.c,v 1.3 2003/01/21 23:26:03 nathanw Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Nathan J. Williams.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *        This product includes software developed by the NetBSD
     21  *        Foundation, Inc. and its contributors.
     22  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23  *    contributors may be used to endorse or promote products derived
     24  *    from this software without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36  * POSSIBILITY OF SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 __RCSID("$NetBSD: flockfile.c,v 1.3 2003/01/21 23:26:03 nathanw Exp $");
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include "namespace.h"
     45 
     46 #include <assert.h>
     47 #include <errno.h>
     48 #include <stdio.h>
     49 #include <string.h>
     50 #include "reentrant.h"
     51 #include "local.h"
     52 
     53 #ifdef __weak_alias
     54 __weak_alias(flockfile,_flockfile)
     55 __weak_alias(ftrylockfile,_ftrylockfile)
     56 __weak_alias(funlockfile,_funlockfile)
     57 #endif
     58 
     59 #ifdef _REENTRANT
     60 /*
     61  * XXX This code makes the assumption that a thr_t (pthread_t) is a
     62  * XXX pointer.
     63  */
     64 void
     65 __smutex_init(mutex_t *m)
     66 {
     67 	mutexattr_t attr;
     68 
     69 	mutexattr_init(&attr);
     70 	mutexattr_settype(&attr, MUTEX_TYPE_RECURSIVE);
     71 
     72 	mutex_init(m, &attr);
     73 
     74 	mutexattr_destroy(&attr);
     75 }
     76 
     77 extern int __isthreaded;
     78 
     79 void
     80 flockfile(FILE *fp)
     81 {
     82 
     83 	if (__isthreaded == 0)
     84 		return;
     85 
     86 	mutex_lock(&_LOCK(fp));
     87 }
     88 
     89 int
     90 ftrylockfile(FILE *fp)
     91 {
     92 
     93 	if (__isthreaded == 0)
     94 		return 0;
     95 
     96 	return mutex_trylock(&_LOCK(fp));
     97 }
     98 
     99 void
    100 funlockfile(FILE *fp)
    101 {
    102 
    103 	if (__isthreaded == 0)
    104 		return;
    105 
    106 	mutex_unlock(&_LOCK(fp));
    107 }
    108 
    109 #else /* _REENTRANT */
    110 
    111 void
    112 flockfile(FILE *fp)
    113 {
    114 	/* LINTED deliberate lack of effect */
    115 	(void)fp;
    116 
    117 	return;
    118 }
    119 
    120 int
    121 ftrylockfile(FILE *fp)
    122 {
    123 	/* LINTED deliberate lack of effect */
    124 	(void)fp;
    125 
    126 	return (0);
    127 }
    128 
    129 void
    130 funlockfile(FILE *fp)
    131 {
    132 	/* LINTED deliberate lack of effect */
    133 	(void)fp;
    134 
    135 	return;
    136 }
    137 
    138 #endif /* _REENTRANT */
    139