xref: /titanic_44/usr/src/lib/libast/common/sfio/sfmutex.c (revision 3e14f97f673e8a630f076077de35afdd43dc1587)
1da2e3ebdSchin /***********************************************************************
2da2e3ebdSchin *                                                                      *
3da2e3ebdSchin *               This software is part of the ast package               *
4*3e14f97fSRoger A. Faulkner *          Copyright (c) 1985-2010 AT&T Intellectual Property          *
5da2e3ebdSchin *                      and is licensed under the                       *
6da2e3ebdSchin *                  Common Public License, Version 1.0                  *
77c2fbfb3SApril Chin *                    by AT&T Intellectual Property                     *
8da2e3ebdSchin *                                                                      *
9da2e3ebdSchin *                A copy of the License is available at                 *
10da2e3ebdSchin *            http://www.opensource.org/licenses/cpl1.0.txt             *
11da2e3ebdSchin *         (with md5 checksum 059e8cd6165cb4c31e351f2b69388fd9)         *
12da2e3ebdSchin *                                                                      *
13da2e3ebdSchin *              Information and Software Systems Research               *
14da2e3ebdSchin *                            AT&T Research                             *
15da2e3ebdSchin *                           Florham Park NJ                            *
16da2e3ebdSchin *                                                                      *
17da2e3ebdSchin *                 Glenn Fowler <gsf@research.att.com>                  *
18da2e3ebdSchin *                  David Korn <dgk@research.att.com>                   *
19da2e3ebdSchin *                   Phong Vo <kpv@research.att.com>                    *
20da2e3ebdSchin *                                                                      *
21da2e3ebdSchin ***********************************************************************/
22da2e3ebdSchin #include	"sfhdr.h"
23da2e3ebdSchin 
24da2e3ebdSchin /*	Obtain/release exclusive use of a stream.
25da2e3ebdSchin **
26da2e3ebdSchin **	Written by Kiem-Phong Vo.
27da2e3ebdSchin */
28da2e3ebdSchin 
29da2e3ebdSchin /* the main locking/unlocking interface */
30da2e3ebdSchin #if __STD_C
sfmutex(Sfio_t * f,int type)31da2e3ebdSchin int sfmutex(Sfio_t* f, int type)
32da2e3ebdSchin #else
33da2e3ebdSchin int sfmutex(f, type)
34da2e3ebdSchin Sfio_t*	f;
35da2e3ebdSchin int	type;
36da2e3ebdSchin #endif
37da2e3ebdSchin {
38da2e3ebdSchin #if !vt_threaded
39da2e3ebdSchin 	NOTUSED(f); NOTUSED(type);
40da2e3ebdSchin 	return 0;
41da2e3ebdSchin #else
42da2e3ebdSchin 
43da2e3ebdSchin 	SFONCE();
44da2e3ebdSchin 
45da2e3ebdSchin 	if(!f)
46da2e3ebdSchin 		return -1;
47da2e3ebdSchin 
48da2e3ebdSchin 	if(!f->mutex)
49da2e3ebdSchin 	{	if(f->bits&SF_PRIVATE)
50da2e3ebdSchin 			return 0;
51da2e3ebdSchin 
52da2e3ebdSchin 		vtmtxlock(_Sfmutex);
53da2e3ebdSchin 		f->mutex = vtmtxopen(NIL(Vtmutex_t*), VT_INIT);
54da2e3ebdSchin 		vtmtxunlock(_Sfmutex);
55da2e3ebdSchin 		if(!f->mutex)
56da2e3ebdSchin 			return -1;
57da2e3ebdSchin 	}
58da2e3ebdSchin 
59da2e3ebdSchin 	if(type == SFMTX_LOCK)
60da2e3ebdSchin 		return vtmtxlock(f->mutex);
61da2e3ebdSchin 	else if(type == SFMTX_TRYLOCK)
62da2e3ebdSchin 		return vtmtxtrylock(f->mutex);
63da2e3ebdSchin 	else if(type == SFMTX_UNLOCK)
64da2e3ebdSchin 		return vtmtxunlock(f->mutex);
65da2e3ebdSchin 	else if(type == SFMTX_CLRLOCK)
66da2e3ebdSchin 		return vtmtxclrlock(f->mutex);
67da2e3ebdSchin 	else	return -1;
68da2e3ebdSchin #endif /*vt_threaded*/
69da2e3ebdSchin }
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