xref: /netbsd-src/lib/libc/stdio/fdopen.c (revision bfb6cb13d599546df69c7e4d20d70e22e15a549d)
1 /*	$NetBSD: fdopen.c,v 1.14 2003/08/07 16:43:22 agc 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. Neither the name of the University nor the names of its contributors
19  *    may be used to endorse or promote products derived from this software
20  *    without specific prior written permission.
21  *
22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  */
34 
35 #include <sys/cdefs.h>
36 #if defined(LIBC_SCCS) && !defined(lint)
37 #if 0
38 static char sccsid[] = "@(#)fdopen.c	8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: fdopen.c,v 1.14 2003/08/07 16:43:22 agc Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43 
44 #include "namespace.h"
45 #include <sys/types.h>
46 
47 #include <assert.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <unistd.h>
51 #include <stdio.h>
52 
53 #include "reentrant.h"
54 #include "local.h"
55 
56 #ifdef __weak_alias
57 __weak_alias(fdopen,_fdopen)
58 #endif
59 
60 FILE *
61 fdopen(fd, mode)
62 	int fd;
63 	const char *mode;
64 {
65 	FILE *fp;
66 	int flags, oflags, fdflags, tmp;
67 
68 	_DIAGASSERT(fd != -1);
69 
70 	if ((flags = __sflags(mode, &oflags)) == 0)
71 		return (NULL);
72 
73 	/* Make sure the mode the user wants is a subset of the actual mode. */
74 	if ((fdflags = fcntl(fd, F_GETFL, 0)) < 0)
75 		return (NULL);
76 	tmp = fdflags & O_ACCMODE;
77 	if (tmp != O_RDWR && (tmp != (oflags & O_ACCMODE))) {
78 		errno = EINVAL;
79 		return (NULL);
80 	}
81 
82 	if (oflags & O_NONBLOCK) {
83 		struct stat st;
84 		if (fstat(fd, &st) == -1) {
85 			return (NULL);
86 		}
87 		if (!S_ISREG(st.st_mode)) {
88 			errno = EFTYPE;
89 			return (NULL);
90 		}
91 	}
92 
93 	if ((fp = __sfp()) == NULL)
94 		return (NULL);
95 	fp->_flags = flags;
96 	/*
97 	 * If opened for appending, but underlying descriptor does not have
98 	 * O_APPEND bit set, assert __SAPP so that __swrite() will lseek to
99 	 * end before each write.
100 	 */
101 	if ((oflags & O_APPEND) && !(fdflags & O_APPEND))
102 		fp->_flags |= __SAPP;
103 	fp->_file = fd;
104 	fp->_cookie = fp;
105 	fp->_read = __sread;
106 	fp->_write = __swrite;
107 	fp->_seek = __sseek;
108 	fp->_close = __sclose;
109 	return (fp);
110 }
111