xref: /freebsd/lib/libc/stdio/fdopen.c (revision c17d43407fe04133a94055b0dbc7ea8965654a9f)
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)
38 static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
39 #endif /* LIBC_SCCS and not lint */
40 #include <sys/cdefs.h>
41 __FBSDID("$FreeBSD$");
42 
43 #include "namespace.h"
44 #include <sys/types.h>
45 #include <fcntl.h>
46 #include <unistd.h>
47 #include <stdio.h>
48 #include <errno.h>
49 #include "un-namespace.h"
50 #include "local.h"
51 
52 FILE *
53 fdopen(fd, mode)
54 	int fd;
55 	const char *mode;
56 {
57 	FILE *fp;
58 	static int nofile;
59 	int flags, oflags, fdflags, tmp;
60 
61 	if (nofile == 0)
62 		nofile = getdtablesize();
63 
64 	if ((flags = __sflags(mode, &oflags)) == 0)
65 		return (NULL);
66 
67 	/* Make sure the mode the user wants is a subset of the actual mode. */
68 	if ((fdflags = _fcntl(fd, F_GETFL, 0)) < 0)
69 		return (NULL);
70 	tmp = fdflags & O_ACCMODE;
71 	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
72 		errno = EINVAL;
73 		return (NULL);
74 	}
75 
76 	if ((fp = __sfp()) == NULL)
77 		return (NULL);
78 	fp->_flags = flags;
79 	/*
80 	 * If opened for appending, but underlying descriptor does not have
81 	 * O_APPEND bit set, assert __SAPP so that __swrite() caller
82 	 * will _sseek() to the end before write.
83 	 */
84 	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
85 		fp->_flags |= __SAPP;
86 	fp->_file = fd;
87 	fp->_cookie = fp;
88 	fp->_read = __sread;
89 	fp->_write = __swrite;
90 	fp->_seek = __sseek;
91 	fp->_close = __sclose;
92 	return (fp);
93 }
94