xref: /netbsd-src/lib/libc/stdio/stdio.c (revision 567219e1d7461bff1b180e494a9674a287b057a7)
1 /*	$NetBSD: stdio.c,v 1.20 2012/03/20 01:42:59 christos Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Chris Torek.
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. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: stdio.c,v 1.20 2012/03/20 01:42:59 christos Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43 
44 #include "namespace.h"
45 
46 #include <assert.h>
47 #include <errno.h>
48 #include <fcntl.h>
49 #include <stdio.h>
50 #include <unistd.h>
51 
52 #include "reentrant.h"
53 #include "local.h"
54 
55 /*
56  * Small standard I/O/seek/close functions.
57  * These maintain the `known seek offset' for seek optimisation.
58  */
59 int
60 __sread(void *cookie, char *buf, int n)
61 {
62 	FILE *fp = cookie;
63 	ssize_t ret;
64 
65 	_DIAGASSERT(fp != NULL);
66 	_DIAGASSERT(buf != NULL);
67 
68 	ret = read(__sfileno(fp), buf, (size_t)n);
69 	/* if the read succeeded, update the current offset */
70 	if (ret >= 0)
71 		fp->_offset += ret;
72 	else
73 		fp->_flags &= ~__SOFF;	/* paranoia */
74 
75 	return (int)ret;
76 }
77 
78 int
79 __swrite(void *cookie, char const *buf, int n)
80 {
81 	FILE *fp = cookie;
82 
83 	_DIAGASSERT(cookie != NULL);
84 	_DIAGASSERT(buf != NULL);
85 
86 	if (fp->_flags & __SAPP)
87 		(void) lseek(__sfileno(fp), (off_t)0, SEEK_END);
88 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
89 	return (int)write(__sfileno(fp), buf, (size_t)n);
90 }
91 
92 off_t
93 __sseek(void *cookie, off_t offset, int whence)
94 {
95 	FILE *fp = cookie;
96 	off_t ret;
97 
98 	_DIAGASSERT(fp != NULL);
99 
100 	ret = lseek(__sfileno(fp), offset, whence);
101 	if (ret == -1L)
102 		fp->_flags &= ~__SOFF;
103 	else {
104 		fp->_flags |= __SOFF;
105 		fp->_offset = ret;
106 	}
107 	return ret;
108 }
109 
110 int
111 __sclose(void *cookie)
112 {
113 
114 	_DIAGASSERT(cookie != NULL);
115 
116 	return close(__sfileno((FILE *)cookie));
117 }
118