xref: /netbsd-src/lib/libc/stdio/fdopen.c (revision 1ffa7b76c40339c17a0fb2a09fac93f287cfc046)
1 /*	$NetBSD: fdopen.c,v 1.13 2003/01/18 11:29:51 thorpej Exp $	*/
2 
3 /*-
4  * Copyright (c) 1990, 1993
5  *	The Regents of the University of California.  All rights reserved.
6  *
7  * This code is derived from software contributed to Berkeley by
8  * Chris Torek.
9  *
10  * Redistribution and use in source and binary forms, with or without
11  * modification, are permitted provided that the following conditions
12  * are met:
13  * 1. Redistributions of source code must retain the above copyright
14  *    notice, this list of conditions and the following disclaimer.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  * 3. All advertising materials mentioning features or use of this software
19  *    must display the following acknowledgement:
20  *	This product includes software developed by the University of
21  *	California, Berkeley and its contributors.
22  * 4. Neither the name of the University nor the names of its contributors
23  *    may be used to endorse or promote products derived from this software
24  *    without specific prior written permission.
25  *
26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
36  * SUCH DAMAGE.
37  */
38 
39 #include <sys/cdefs.h>
40 #if defined(LIBC_SCCS) && !defined(lint)
41 #if 0
42 static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
43 #else
44 __RCSID("$NetBSD: fdopen.c,v 1.13 2003/01/18 11:29:51 thorpej Exp $");
45 #endif
46 #endif /* LIBC_SCCS and not lint */
47 
48 #include "namespace.h"
49 #include <sys/types.h>
50 
51 #include <assert.h>
52 #include <errno.h>
53 #include <fcntl.h>
54 #include <unistd.h>
55 #include <stdio.h>
56 
57 #include "reentrant.h"
58 #include "local.h"
59 
60 #ifdef __weak_alias
61 __weak_alias(fdopen,_fdopen)
62 #endif
63 
64 FILE *
65 fdopen(fd, mode)
66 	int fd;
67 	const char *mode;
68 {
69 	FILE *fp;
70 	int flags, oflags, fdflags, tmp;
71 
72 	_DIAGASSERT(fd != -1);
73 
74 	if ((flags = __sflags(mode, &oflags)) == 0)
75 		return (NULL);
76 
77 	/* Make sure the mode the user wants is a subset of the actual mode. */
78 	if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
79 		return (NULL);
80 	tmp = fdflags & O_ACCMODE;
81 	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
82 		errno = EINVAL;
83 		return (NULL);
84 	}
85 
86 	if (oflags & O_NONBLOCK) {
87 		struct stat st;
88 		if (fstat(fd, &st) == -1) {
89 			return (NULL);
90 		}
91 		if (!S_ISREG(st.st_mode)) {
92 			errno = EFTYPE;
93 			return (NULL);
94 		}
95 	}
96 
97 	if ((fp = __sfp()) == NULL)
98 		return (NULL);
99 	fp->_flags = flags;
100 	/*
101 	 * If opened for appending, but underlying descriptor does not have
102 	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
103 	 * end before each write.
104 	 */
105 	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
106 		fp->_flags |= __SAPP;
107 	fp->_file = fd;
108 	fp->_cookie = fp;
109 	fp->_read = __sread;
110 	fp->_write = __swrite;
111 	fp->_seek = __sseek;
112 	fp->_close = __sclose;
113 	return (fp);
114 }
115