xref: /netbsd/lib/libc/stdio/flags.c (revision bf9ec67e)
1 /*	$NetBSD: flags.c,v 1.12 2000/01/15 01:11:45 christos 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 1.12 2000/01/15 01:11:45 christos 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 "local.h"
54 
55 /*
56  * Return the (stdio) flags for a given mode.  Store the flags
57  * to be passed to an open() syscall through *optr.
58  * Return 0 on error.
59  */
60 int
61 __sflags(mode, optr)
62 	const char *mode;
63 	int *optr;
64 {
65 	int ret, m, o;
66 
67 	_DIAGASSERT(mode != NULL);
68 
69 	switch (*mode++) {
70 
71 	case 'r':	/* open for reading */
72 		ret = __SRD;
73 		m = O_RDONLY;
74 		o = 0;
75 		break;
76 
77 	case 'w':	/* open for writing */
78 		ret = __SWR;
79 		m = O_WRONLY;
80 		o = O_CREAT | O_TRUNC;
81 		break;
82 
83 	case 'a':	/* open for appending */
84 		ret = __SWR;
85 		m = O_WRONLY;
86 		o = O_CREAT | O_APPEND;
87 		break;
88 
89 	default:	/* illegal mode */
90 		errno = EINVAL;
91 		return (0);
92 	}
93 
94 	/*
95 	 * [rwa]\+ or [rwa]b\+ means read and write
96 	 * f means open only plain files.
97 	 */
98 	for (; *mode; mode++)
99 		switch (*mode) {
100 		case '+':
101 			ret = __SRW;
102 			m = O_RDWR;
103 			break;
104 		case 'f':
105 			o |= O_NONBLOCK;
106 			break;
107 		case 'b':
108 			break;
109 		default:	/* We could produce a warning here */
110 			break;
111 		}
112 
113 	*optr = m | o;
114 	return (ret);
115 }
116