xref: /titanic_51/usr/src/lib/libast/common/sfio/sfclrlock.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 /*	Function to clear a locked stream.
25da2e3ebdSchin **	This is useful for programs that longjmp from the mid of an sfio function.
26da2e3ebdSchin **	There is no guarantee on data integrity in such a case.
27da2e3ebdSchin **
28da2e3ebdSchin **	Written by Kiem-Phong Vo
29da2e3ebdSchin */
30da2e3ebdSchin #if __STD_C
sfclrlock(Sfio_t * f)317c2fbfb3SApril Chin int sfclrlock(Sfio_t* f)
32da2e3ebdSchin #else
33da2e3ebdSchin int sfclrlock(f)
347c2fbfb3SApril Chin Sfio_t	*f;
35da2e3ebdSchin #endif
36da2e3ebdSchin {
37da2e3ebdSchin 	int	rv;
387c2fbfb3SApril Chin 	SFMTXDECL(f);
39da2e3ebdSchin 
40da2e3ebdSchin 	/* already closed */
41da2e3ebdSchin 	if(f && (f->mode&SF_AVAIL))
42da2e3ebdSchin 		return 0;
43da2e3ebdSchin 
447c2fbfb3SApril Chin 	SFMTXENTER(f,0);
45da2e3ebdSchin 
46da2e3ebdSchin 	/* clear error bits */
47da2e3ebdSchin 	f->flags &= ~(SF_ERROR|SF_EOF);
48da2e3ebdSchin 
49da2e3ebdSchin 	/* clear peek locks */
50da2e3ebdSchin 	if(f->mode&SF_PKRD)
51da2e3ebdSchin 	{	f->here -= f->endb-f->next;
52da2e3ebdSchin 		f->endb = f->next;
53da2e3ebdSchin 	}
54da2e3ebdSchin 
55da2e3ebdSchin 	SFCLRBITS(f);
56da2e3ebdSchin 
57da2e3ebdSchin 	/* throw away all lock bits except for stacking state SF_PUSH */
58da2e3ebdSchin 	f->mode &= (SF_RDWR|SF_INIT|SF_POOL|SF_PUSH|SF_SYNCED|SF_STDIO);
59da2e3ebdSchin 
60da2e3ebdSchin 	rv = (f->mode&SF_PUSH) ? 0 : (f->flags&SF_FLAGS);
61da2e3ebdSchin 
62da2e3ebdSchin 	SFMTXRETURN(f, rv);
63da2e3ebdSchin }
64