1/*	$NetBSD: fopen.c,v 1.13 2008/03/13 15:40:00 christos Exp $	*/
2
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 <sys/cdefs.h>
36#if defined(LIBC_SCCS) && !defined(lint)
37#if 0
38static char sccsid[] = "@(#)fopen.c	8.1 (Berkeley) 6/4/93";
39#else
40__RCSID("$NetBSD: fopen.c,v 1.13 2008/03/13 15:40:00 christos Exp $");
41#endif
42#endif /* LIBC_SCCS and not lint */
43
44#include <sys/types.h>
45#include <sys/stat.h>
46#include <assert.h>
47#include <fcntl.h>
48#include <unistd.h>
49#include <stdio.h>
50#include <errno.h>
51#include <limits.h>
52#include "reentrant.h"
53#include "local.h"
54
55FILE *
56fopen(file, mode)
57	const char *file;
58	const char *mode;
59{
60	FILE *fp;
61	int f;
62	int flags, oflags;
63
64	_DIAGASSERT(file != NULL);
65	if ((flags = __sflags(mode, &oflags)) == 0)
66		return (NULL);
67	if ((fp = __sfp()) == NULL)
68		return (NULL);
69	if ((f = open(file, oflags, DEFFILEMODE)) < 0)
70		goto release;
71	if (oflags & O_NONBLOCK) {
72		struct stat st;
73		if (fstat(f, &st) == -1) {
74			int sverrno = errno;
75			(void)close(f);
76			errno = sverrno;
77			goto release;
78		}
79		if (!S_ISREG(st.st_mode)) {
80			(void)close(f);
81			errno = EFTYPE;
82			goto release;
83		}
84	}
85	/*
86	 * File descriptors are a full int, but _file is only a short.
87	 * If we get a valid file descriptor that is greater or equal to
88	 * USHRT_MAX, then the fd will get sign-extended into an
89	 * invalid file descriptor.  Handle this case by failing the
90	 * open. (We treat the short as unsigned, and special-case -1).
91	 */
92	if (f >= USHRT_MAX) {
93		errno = EMFILE;
94		goto release;
95	}
96
97	fp->_file = f;
98	fp->_flags = flags;
99	fp->_cookie = fp;
100	fp->_read = __sread;
101	fp->_write = __swrite;
102	fp->_seek = __sseek;
103	fp->_close = __sclose;
104
105	/*
106	 * When opening in append mode, even though we use O_APPEND,
107	 * we need to seek to the end so that ftell() gets the right
108	 * answer.  If the user then alters the seek pointer, or
109	 * the file extends, this will fail, but there is not much
110	 * we can do about this.  (We could set __SAPP and check in
111	 * fseek and ftell.)
112	 */
113	if (oflags & O_APPEND)
114		(void) __sseek((void *)fp, (off_t)0, SEEK_END);
115	return (fp);
116release:
117	fp->_flags = 0;			/* release */
118	return (NULL);
119}
120