xref: /freebsd/lib/libc/stdio/fdopen.c (revision 1e413cf93298b5b97441a21d9a50fdcd0ee9945e)
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  * 4. Neither the name of the University nor the names of its contributors
17  *    may be used to endorse or promote products derived from this software
18  *    without specific prior written permission.
19  *
20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30  * SUCH DAMAGE.
31  */
32 
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38 
39 #include "namespace.h"
40 #include <sys/types.h>
41 #include <fcntl.h>
42 #include <unistd.h>
43 #include <stdio.h>
44 #include <errno.h>
45 #include "un-namespace.h"
46 #include "local.h"
47 
48 FILE *
49 fdopen(fd, mode)
50 	int fd;
51 	const char *mode;
52 {
53 	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() caller
78 	 * will _sseek() to the end before 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