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1/* $OpenBSD: fopen.c,v 1.11 2025/08/08 15:58:53 yasuoka Exp $ */
2/*-
3 * Copyright (c) 1990, 1993
4 * The Regents of the University of California. All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Chris Torek.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 * notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 * notice, this list of conditions and the following disclaimer in the
16 * documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 * may be used to endorse or promote products derived from this software
19 * without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/types.h>
35#include <sys/stat.h>
36#include <fcntl.h>
37#include <limits.h>
38#include <stdio.h>
39#include <errno.h>
40#include <unistd.h>
41#include "local.h"
42
43FILE *
44fopen(const char *file, const char *mode)
45{
46 FILE *fp;
47 int f;
48 int flags, oflags;
49
50 if ((flags = __sflags(mode, &oflags)) == 0)
51 return (NULL);
52 if ((fp = __sfp()) == NULL)
53 return (NULL);
54 if ((f = open(file, oflags, DEFFILEMODE)) == -1) {
55 fp->_flags = 0; /* release */
56 return (NULL);
57 }
58
59 fp->_file = f;
60 fp->_flags = flags;
61 fp->_cookie = fp;
62 fp->_read = __sread;
63 fp->_write = __swrite;
64 fp->_seek = __sseek;
65 fp->_close = __sclose;
66
67 /*
68 * When opening in append mode, even though we use O_APPEND,
69 * we need to seek to the end so that ftell() gets the right
70 * answer. If the user then alters the seek pointer, or
71 * the file extends, this will fail, but there is not much
72 * we can do about this. (We could set __SAPP and check in
73 * fseek and ftell.)
74 */
75 if (oflags & O_APPEND)
76 (void) __sseek(fp, 0, SEEK_END);
77 return (fp);
78}
79DEF_STRONG(fopen);