fdopen.c revision 1574 
1/*-
2 * Copyright (c) 1990, 1993
3 *	The Regents of the University of California.  All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 *    notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 *    notice, this list of conditions and the following disclaimer in the
15 *    documentation and/or other materials provided with the distribution.
16 * 3. All advertising materials mentioning features or use of this software
17 *    must display the following acknowledgement:
18 *	This product includes software developed by the University of
19 *	California, Berkeley and its contributors.
20 * 4. Neither the name of the University nor the names of its contributors
21 *    may be used to endorse or promote products derived from this software
22 *    without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#if defined(LIBC_SCCS) && !defined(lint)
38static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
39#endif /* LIBC_SCCS and not lint */
40
41#include <sys/types.h>
42#include <fcntl.h>
43#include <unistd.h>
44#include <stdio.h>
45#include <errno.h>
46#include "local.h"
47
48FILE *
49fdopen(fd, mode)
50	int fd;
51	const char *mode;
52{
53	register FILE *fp;
54	static int nofile;
55	int flags, oflags, fdflags, tmp;
56
57	if (nofile == 0)
58		nofile = getdtablesize();
59
60	if ((flags = __sflags(mode, &oflags)) == 0)
61		return (NULL);
62
63	/* Make sure the mode the user wants is a subset of the actual mode. */
64	if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
65		return (NULL);
66	tmp = fdflags & O_ACCMODE;
67	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
68		errno = EINVAL;
69		return (NULL);
70	}
71
72	if ((fp = __sfp()) == NULL)
73		return (NULL);
74	fp->_flags = flags;
75	/*
76	 * If opened for appending, but underlying descriptor does not have
77	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
78	 * end before each write.
79	 */
80	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
81		fp->_flags |= __SAPP;
82	fp->_file = fd;
83	fp->_cookie = fp;
84	fp->_read = __sread;
85	fp->_write = __swrite;
86	fp->_seek = __sseek;
87	fp->_close = __sclose;
88	return (fp);
89}
90