1 /* $NetBSD: flags.c,v 1.19 2017/11/09 20:30:02 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. 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[] = "@(#)flags.c 8.1 (Berkeley) 6/4/93";
39 #else
40 __RCSID("$NetBSD: flags.c,v 1.19 2017/11/09 20:30:02 christos Exp $");
41 #endif
42 #endif /* LIBC_SCCS and not lint */
43
44 #include <sys/types.h>
45 #include <assert.h>
46 #include <fcntl.h>
47 #include <stdio.h>
48 #include <errno.h>
49 #include "reentrant.h"
50 #include "local.h"
51
52 /*
53 * Return the (stdio) flags for a given mode. Store the flags
54 * to be passed to an open() syscall through *optr.
55 * Return 0 on error.
56 */
57 int
__sflags(const char * mode,int * optr)58 __sflags(const char *mode, int *optr)
59 {
60 int ret, m, o;
61
62 _DIAGASSERT(mode != NULL);
63
64 switch (*mode++) {
65
66 case 'r': /* open for reading */
67 ret = __SRD;
68 m = O_RDONLY;
69 o = 0;
70 break;
71
72 case 'w': /* open for writing */
73 ret = __SWR;
74 m = O_WRONLY;
75 o = O_CREAT | O_TRUNC;
76 break;
77
78 case 'a': /* open for appending */
79 ret = __SWR;
80 m = O_WRONLY;
81 o = O_CREAT | O_APPEND;
82 break;
83
84 default: /* illegal mode */
85 errno = EINVAL;
86 return 0;
87 }
88
89 /*
90 * [rwa]\+ or [rwa]b\+ means read and write
91 * e means set close on exec.
92 * f means open only plain files.
93 * l means don't follow symlinks.
94 * x means exclusive open.
95 */
96 for (; *mode; mode++)
97 switch (*mode) {
98 case '+':
99 ret = __SRW;
100 m = O_RDWR;
101 break;
102 case 'b':
103 break;
104 case 'e':
105 o |= O_CLOEXEC;
106 break;
107 case 'f':
108 o |= O_REGULAR;
109 break;
110 case 'l':
111 o |= O_NOFOLLOW;
112 break;
113 case 'x':
114 o |= O_EXCL;
115 break;
116 default: /* We could produce a warning here */
117 break;
118 }
119
120 *optr = m | o;
121 return ret;
122 }
123