1 /*-
2 * Copyright (c) 1990, 1993
3 * The Regents of the University of California. All rights reserved.
4 *
5 * This code is derived from software contributed to Berkeley by
6 * Chris Torek.
7 *
8 * Redistribution and use in source and binary forms, with or without
9 * modification, are permitted provided that the following conditions
10 * are met:
11 * 1. Redistributions of source code must retain the above copyright
12 * notice, this list of conditions and the following disclaimer.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 * 3. Neither the name of the University nor the names of its contributors
17 * may be used to endorse or promote products derived from this software
18 * without specific prior written permission.
19 *
20 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
21 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
22 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
23 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 */
32
33 #if defined(LIBC_SCCS) && !defined(lint)
34 static char sccsid[] = "@(#)flags.c 8.1 (Berkeley) 6/4/93";
35 #endif /* LIBC_SCCS and not lint */
36 #include <sys/cdefs.h>
37 __FBSDID("$FreeBSD$");
38
39 #include <sys/types.h>
40 #include <sys/file.h>
41 #include <stdio.h>
42 #include <errno.h>
43
44 #include "local.h"
45
46 /*
47 * Return the (stdio) flags for a given mode. Store the flags
48 * to be passed to an _open() syscall through *optr.
49 * Return 0 on error.
50 */
51 int
__sflags(const char * mode,int * optr)52 __sflags(const char *mode, int *optr)
53 {
54 int ret, m, o;
55
56 switch (*mode++) {
57
58 case 'r': /* open for reading */
59 ret = __SRD;
60 m = O_RDONLY;
61 o = 0;
62 break;
63
64 case 'w': /* open for writing */
65 ret = __SWR;
66 m = O_WRONLY;
67 o = O_CREAT | O_TRUNC;
68 break;
69
70 case 'a': /* open for appending */
71 ret = __SWR;
72 m = O_WRONLY;
73 o = O_CREAT | O_APPEND;
74 break;
75
76 default: /* illegal mode */
77 errno = EINVAL;
78 return (0);
79 }
80
81 /* 'b' (binary) is ignored */
82 if (*mode == 'b')
83 mode++;
84
85 /* [rwa][b]\+ means read and write */
86 if (*mode == '+') {
87 mode++;
88 ret = __SRW;
89 m = O_RDWR;
90 }
91
92 /* 'b' (binary) can appear here, too -- and is ignored again */
93 if (*mode == 'b')
94 mode++;
95
96 /* 'x' means exclusive (fail if the file exists) */
97 if (*mode == 'x') {
98 mode++;
99 if (m == O_RDONLY) {
100 errno = EINVAL;
101 return (0);
102 }
103 o |= O_EXCL;
104 }
105
106 /* set close-on-exec */
107 if (*mode == 'e')
108 o |= O_CLOEXEC;
109
110 *optr = m | o;
111 return (ret);
112 }
113