xref: /freebsd/lib/libc/stdio/fdopen.c (revision daf1cffce2e07931f27c6c6998652e90df6ba87e)
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  * $FreeBSD$
37  */
38 
39 #if defined(LIBC_SCCS) && !defined(lint)
40 static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
41 #endif /* LIBC_SCCS and not lint */
42 
43 #include <sys/types.h>
44 #include <fcntl.h>
45 #include <unistd.h>
46 #include <stdio.h>
47 #include <errno.h>
48 #include "local.h"
49 
50 FILE *
51 fdopen(fd, mode)
52 	int fd;
53 	const char *mode;
54 {
55 	register FILE *fp;
56 	static int nofile;
57 	int flags, oflags, fdflags, tmp;
58 
59 	if (nofile == 0)
60 		nofile = getdtablesize();
61 
62 	if ((flags = __sflags(mode, &oflags)) == 0)
63 		return (NULL);
64 
65 	/* Make sure the mode the user wants is a subset of the actual mode. */
66 	if ((fdflags = _fcntl(fd, F_GETFL, 0)) < 0)
67 		return (NULL);
68 	tmp = fdflags & O_ACCMODE;
69 	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
70 		errno = EINVAL;
71 		return (NULL);
72 	}
73 
74 	if ((fp = __sfp()) == NULL)
75 		return (NULL);
76 	fp->_flags = flags;
77 	/*
78 	 * If opened for appending, but underlying descriptor does not have
79 	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
80 	 * end before each write.
81 	 */
82 	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
83 		fp->_flags |= __SAPP;
84 	fp->_file = fd;
85 	fp->_cookie = fp;
86 	fp->_read = __sread;
87 	fp->_write = __swrite;
88 	fp->_seek = __sseek;
89 	fp->_close = __sclose;
90 	return (fp);
91 }
92