xref: /netbsd-src/lib/libc/stdio/flags.c (revision 1ffa7b76c40339c17a0fb2a09fac93f287cfc046)
1 /*	$NetBSD: flags.c,v 1.13 2003/01/18 11:29:52 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[] = "@(#)flags.c	8.1 (Berkeley) 6/4/93";
43 #else
44 __RCSID("$NetBSD: flags.c,v 1.13 2003/01/18 11:29:52 thorpej Exp $");
45 #endif
46 #endif /* LIBC_SCCS and not lint */
47 
48 #include <sys/types.h>
49 #include <assert.h>
50 #include <fcntl.h>
51 #include <stdio.h>
52 #include <errno.h>
53 #include "reentrant.h"
54 #include "local.h"
55 
56 /*
57  * Return the (stdio) flags for a given mode.  Store the flags
58  * to be passed to an open() syscall through *optr.
59  * Return 0 on error.
60  */
61 int
62 __sflags(mode, optr)
63 	const char *mode;
64 	int *optr;
65 {
66 	int ret, m, o;
67 
68 	_DIAGASSERT(mode != NULL);
69 
70 	switch (*mode++) {
71 
72 	case 'r':	/* open for reading */
73 		ret = __SRD;
74 		m = O_RDONLY;
75 		o = 0;
76 		break;
77 
78 	case 'w':	/* open for writing */
79 		ret = __SWR;
80 		m = O_WRONLY;
81 		o = O_CREAT | O_TRUNC;
82 		break;
83 
84 	case 'a':	/* open for appending */
85 		ret = __SWR;
86 		m = O_WRONLY;
87 		o = O_CREAT | O_APPEND;
88 		break;
89 
90 	default:	/* illegal mode */
91 		errno = EINVAL;
92 		return (0);
93 	}
94 
95 	/*
96 	 * [rwa]\+ or [rwa]b\+ means read and write
97 	 * f means open only plain files.
98 	 */
99 	for (; *mode; mode++)
100 		switch (*mode) {
101 		case '+':
102 			ret = __SRW;
103 			m = O_RDWR;
104 			break;
105 		case 'f':
106 			o |= O_NONBLOCK;
107 			break;
108 		case 'b':
109 			break;
110 		default:	/* We could produce a warning here */
111 			break;
112 		}
113 
114 	*optr = m | o;
115 	return (ret);
116 }
117