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#include "namespace.h"
36#include <sys/types.h>
37#include <sys/stat.h>
38#include <fcntl.h>
39#include <unistd.h>
40#include <stdio.h>
41#include <errno.h>
42#include <limits.h>
43#include "un-namespace.h"
44
45#include "local.h"
46
47FILE *
48fopen(const char * __restrict file, const char * __restrict mode)
49{
50	FILE *fp;
51	int f;
52	int flags, oflags;
53
54	if ((flags = __sflags(mode, &oflags)) == 0)
55		return (NULL);
56	if ((fp = __sfp()) == NULL)
57		return (NULL);
58	if ((f = _open(file, oflags, DEFFILEMODE)) < 0) {
59		fp->_flags = 0;			/* release */
60		return (NULL);
61	}
62	/*
63	 * File descriptors are a full int, but _file is only a short.
64	 * If we get a valid file descriptor that is greater than
65	 * SHRT_MAX, then the fd will get sign-extended into an
66	 * invalid file descriptor.  Handle this case by failing the
67	 * open.
68	 */
69	if (f > SHRT_MAX) {
70		fp->_flags = 0;			/* release */
71		_close(f);
72		errno = EMFILE;
73		return (NULL);
74	}
75	fp->_file = f;
76	fp->_flags = flags;
77	fp->_cookie = fp;
78	fp->_read = __sread;
79	fp->_write = __swrite;
80	fp->_seek = __sseek;
81	fp->_close = __sclose;
82	/*
83	 * When opening in append mode, even though we use O_APPEND,
84	 * we need to seek to the end so that ftell() gets the right
85	 * answer.  If the user then alters the seek pointer, or
86	 * the file extends, this will fail, but there is not much
87	 * we can do about this.  (We could set __SAPP and check in
88	 * fseek and ftell.)
89	 */
90	if (oflags & O_APPEND) {
91		fp->_flags2 |= __S2OAP;
92		(void)_sseek(fp, (fpos_t)0, SEEK_END);
93	}
94	return (fp);
95}
96