xref: /freebsd/lib/libc/stdio/stdio.c (revision 5ebc7e6281887681c3a348a5a4c902e262ccd656)
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. All advertising materials mentioning features or use of this software
17  *    must display the following acknowledgement:
18  *	This product includes software developed by the University of
19  *	California, Berkeley and its contributors.
20  * 4. Neither the name of the University nor the names of its contributors
21  *    may be used to endorse or promote products derived from this software
22  *    without specific prior written permission.
23  *
24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34  * SUCH DAMAGE.
35  */
36 
37 #if defined(LIBC_SCCS) && !defined(lint)
38 static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 
41 #include <fcntl.h>
42 #include <unistd.h>
43 #include <stdio.h>
44 #include "local.h"
45 
46 /*
47  * Small standard I/O/seek/close functions.
48  * These maintain the `known seek offset' for seek optimisation.
49  */
50 __sread(cookie, buf, n)
51 	void *cookie;
52 	char *buf;
53 	int n;
54 {
55 	register FILE *fp = cookie;
56 	register int ret;
57 
58 	ret = read(fp->_file, buf, n);
59 	/* if the read succeeded, update the current offset */
60 	if (ret >= 0)
61 		fp->_offset += ret;
62 	else
63 		fp->_flags &= ~__SOFF;	/* paranoia */
64 	return (ret);
65 }
66 
67 __swrite(cookie, buf, n)
68 	void *cookie;
69 	char const *buf;
70 	int n;
71 {
72 	register FILE *fp = cookie;
73 
74 	if (fp->_flags & __SAPP)
75 		(void) lseek(fp->_file, (off_t)0, SEEK_END);
76 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
77 	return (write(fp->_file, buf, n));
78 }
79 
80 fpos_t
81 __sseek(cookie, offset, whence)
82 	void *cookie;
83 	fpos_t offset;
84 	int whence;
85 {
86 	register FILE *fp = cookie;
87 	register off_t ret;
88 
89 	ret = lseek(fp->_file, (off_t)offset, whence);
90 	if (ret == -1L)
91 		fp->_flags &= ~__SOFF;
92 	else {
93 		fp->_flags |= __SOFF;
94 		fp->_offset = ret;
95 	}
96 	return (ret);
97 }
98 
99 __sclose(cookie)
100 	void *cookie;
101 {
102 
103 	return (close(((FILE *)cookie)->_file));
104 }
105