1/*	$OpenBSD: fdopen.c,v 1.5 2005/08/08 08:05:36 espie 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 <fcntl.h>
36#include <unistd.h>
37#include <stdio.h>
38#include <errno.h>
39#include "local.h"
40
41FILE *
42fdopen(int fd, const char *mode)
43{
44	FILE *fp;
45	int flags, oflags, fdflags, tmp;
46
47	if ((flags = __sflags(mode, &oflags)) == 0)
48		return (NULL);
49
50	/* Make sure the mode the user wants is a subset of the actual mode. */
51	if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
52		return (NULL);
53	tmp = fdflags & O_ACCMODE;
54	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
55		errno = EINVAL;
56		return (NULL);
57	}
58
59	if ((fp = __sfp()) == NULL)
60		return (NULL);
61	fp->_flags = flags;
62	/*
63	 * If opened for appending, but underlying descriptor does not have
64	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
65	 * end before each write.
66	 */
67	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
68		fp->_flags |= __SAPP;
69	fp->_file = fd;
70	fp->_cookie = fp;
71	fp->_read = __sread;
72	fp->_write = __swrite;
73	fp->_seek = __sseek;
74	fp->_close = __sclose;
75	return (fp);
76}
77