xref: /openbsd-src/lib/libc/stdio/stdio.c (revision c5f4fad510dd427c0c20c0f4d164f60ce24651b6)
1 /*-
2  * Copyright (c) 1990, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * This code is derived from software contributed to Berkeley by
6  * Chris Torek.
7  *
8  * Redistribution and use in source and binary forms, with or without
9  * modification, are permitted provided that the following conditions
10  * are met:
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  * 3. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char rcsid[] = "$OpenBSD: stdio.c,v 1.8 2005/03/31 18:36:29 pat Exp $";
35 #endif /* LIBC_SCCS and not lint */
36 
37 #include <fcntl.h>
38 #include <unistd.h>
39 #include <stdio.h>
40 #include "local.h"
41 
42 /*
43  * Small standard I/O/seek/close functions.
44  * These maintain the `known seek offset' for seek optimisation.
45  */
46 int
47 __sread(void *cookie, char *buf, int n)
48 {
49 	FILE *fp = cookie;
50 	int ret;
51 
52 	ret = read(fp->_file, buf, n);
53 	/* if the read succeeded, update the current offset */
54 	if (ret >= 0)
55 		fp->_offset += ret;
56 	else
57 		fp->_flags &= ~__SOFF;	/* paranoia */
58 	return (ret);
59 }
60 
61 int
62 __swrite(void *cookie, const char *buf, int n)
63 {
64 	FILE *fp = cookie;
65 
66 	if (fp->_flags & __SAPP)
67 		(void) lseek(fp->_file, (off_t)0, SEEK_END);
68 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
69 	return (write(fp->_file, buf, n));
70 }
71 
72 fpos_t
73 __sseek(void *cookie, fpos_t offset, int whence)
74 {
75 	FILE *fp = cookie;
76 	off_t ret;
77 
78 	ret = lseek(fp->_file, (off_t)offset, whence);
79 	if (ret == (off_t)-1)
80 		fp->_flags &= ~__SOFF;
81 	else {
82 		fp->_flags |= __SOFF;
83 		fp->_offset = ret;
84 	}
85 	return (ret);
86 }
87 
88 int
89 __sclose(void *cookie)
90 {
91 	return (close(((FILE *)cookie)->_file));
92 }
93