fopen.c revision 1573 
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)
38static char sccsid[] = "@(#)fopen.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/types.h>
42#include <sys/stat.h>
43#include <fcntl.h>
44#include <stdio.h>
45#include <errno.h>
46#include "local.h"
47
48FILE *
49fopen(file, mode)
50	const char *file;
51	const char *mode;
52{
53	register FILE *fp;
54	register int f;
55	int flags, oflags;
56
57	if ((flags = __sflags(mode, &oflags)) == 0)
58		return (NULL);
59	if ((fp = __sfp()) == NULL)
60		return (NULL);
61	if ((f = open(file, oflags, DEFFILEMODE)) < 0) {
62		fp->_flags = 0;			/* release */
63		return (NULL);
64	}
65	fp->_file = f;
66	fp->_flags = flags;
67	fp->_cookie = fp;
68	fp->_read = __sread;
69	fp->_write = __swrite;
70	fp->_seek = __sseek;
71	fp->_close = __sclose;
72
73	/*
74	 * When opening in append mode, even though we use O_APPEND,
75	 * we need to seek to the end so that ftell() gets the right
76	 * answer.  If the user then alters the seek pointer, or
77	 * the file extends, this will fail, but there is not much
78	 * we can do about this.  (We could set __SAPP and check in
79	 * fseek and ftell.)
80	 */
81	if (oflags & O_APPEND)
82		(void) __sseek((void *)fp, (fpos_t)0, SEEK_END);
83	return (fp);
84}
85