1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
3 *
4 * Copyright (c) 1990, 1993
5 * The Regents of the University of California. All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Chris Torek.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 * notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 * notice, this list of conditions and the following disclaimer in the
17 * documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 * may be used to endorse or promote products derived from this software
20 * without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 */
34
35 #if defined(LIBC_SCCS) && !defined(lint)
36 static char sccsid[] = "@(#)fopen.c 8.1 (Berkeley) 6/4/93";
37 #endif /* LIBC_SCCS and not lint */
38 #include "namespace.h"
39 #include <sys/types.h>
40 #include <sys/stat.h>
41 #include <fcntl.h>
42 #include <unistd.h>
43 #include <stdio.h>
44 #include <errno.h>
45 #include <limits.h>
46 #include "un-namespace.h"
47
48 #include "local.h"
49
50 FILE *
fopen(const char * __restrict file,const char * __restrict mode)51 fopen(const char * __restrict file, const char * __restrict mode)
52 {
53 FILE *fp;
54 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 /*
66 * File descriptors are a full int, but _file is only a short.
67 * If we get a valid file descriptor that is greater than
68 * SHRT_MAX, then the fd will get sign-extended into an
69 * invalid file descriptor. Handle this case by failing the
70 * open.
71 */
72 if (f > SHRT_MAX) {
73 fp->_flags = 0; /* release */
74 _close(f);
75 errno = EMFILE;
76 return (NULL);
77 }
78 fp->_file = f;
79 fp->_flags = flags;
80 fp->_cookie = fp;
81 fp->_read = __sread;
82 fp->_write = __swrite;
83 fp->_seek = __sseek;
84 fp->_close = __sclose;
85 /*
86 * When opening in append mode, even though we use O_APPEND,
87 * we need to seek to the end so that ftell() gets the right
88 * answer. If the user then alters the seek pointer, or
89 * the file extends, this will fail, but there is not much
90 * we can do about this. (We could set __SAPP and check in
91 * fseek and ftell.)
92 */
93 if (oflags & O_APPEND) {
94 fp->_flags2 |= __S2OAP;
95 (void)_sseek(fp, (fpos_t)0, SEEK_END);
96 }
97 return (fp);
98 }
99