xref: /freebsd/lib/libc/stdio/fopen.c (revision 51a9219f5780e61e1437d25220bf8750d9df7f8b)
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[] = "@(#)fopen.c	8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "namespace.h"
44 #include <sys/types.h>
45 #include <sys/stat.h>
46 #include <fcntl.h>
47 #include <stdio.h>
48 #include <errno.h>
49 #include "un-namespace.h"
50 
51 #include "local.h"
52 
53 FILE *
54 fopen(file, mode)
55 	const char * __restrict file;
56 	const char * __restrict mode;
57 {
58 	FILE *fp;
59 	int f;
60 	int flags, oflags;
61 
62 	if ((flags = __sflags(mode, &oflags)) == 0)
63 		return (NULL);
64 	if ((fp = __sfp()) == NULL)
65 		return (NULL);
66 	if ((f = _open(file, oflags, DEFFILEMODE)) < 0) {
67 		fp->_flags = 0;			/* release */
68 		return (NULL);
69 	}
70 	fp->_file = f;
71 	fp->_flags = flags;
72 	fp->_cookie = fp;
73 	fp->_read = __sread;
74 	fp->_write = __swrite;
75 	fp->_seek = __sseek;
76 	fp->_close = __sclose;
77 	/*
78 	 * When opening in append mode, even though we use O_APPEND,
79 	 * we need to seek to the end so that ftell() gets the right
80 	 * answer.  If the user then alters the seek pointer, or
81 	 * the file extends, this will fail, but there is not much
82 	 * we can do about this.  (We could set __SAPP and check in
83 	 * fseek and ftell.)
84 	 */
85 	if (oflags & O_APPEND)
86 		(void)_sseek(fp, (fpos_t)0, SEEK_END);
87 	return (fp);
88 }
89