1 /*-
2 * SPDX-License-Identifier: BSD-3-Clause
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/types.h>
36 #include <sys/file.h>
37 #include <stdio.h>
38 #include <errno.h>
39
40 #include "local.h"
41
42 /*
43 * Return the (stdio) flags for a given mode. Store the flags
44 * to be passed to an _open() syscall through *optr.
45 * Return 0 on error.
46 */
47 int
__sflags(const char * mode,int * optr)48 __sflags(const char *mode, int *optr)
49 {
50 int ret, m, o, known;
51
52 switch (*mode++) {
53
54 case 'r': /* open for reading */
55 ret = __SRD;
56 m = O_RDONLY;
57 o = 0;
58 break;
59
60 case 'w': /* open for writing */
61 ret = __SWR;
62 m = O_WRONLY;
63 o = O_CREAT | O_TRUNC;
64 break;
65
66 case 'a': /* open for appending */
67 ret = __SWR;
68 m = O_WRONLY;
69 o = O_CREAT | O_APPEND;
70 break;
71
72 default: /* illegal mode */
73 errno = EINVAL;
74 return (0);
75 }
76
77 do {
78 known = 1;
79 switch (*mode++) {
80 case 'b':
81 /* 'b' (binary) is ignored */
82 break;
83 case '+':
84 /* [rwa][b]\+ means read and write */
85 ret = __SRW;
86 m = O_RDWR;
87 break;
88 case 'x':
89 /* 'x' means exclusive (fail if the file exists) */
90 o |= O_EXCL;
91 break;
92 case 'e':
93 /* set close-on-exec */
94 o |= O_CLOEXEC;
95 break;
96 case 'v':
97 /* verify */
98 o |= O_VERIFY;
99 break;
100 default:
101 known = 0;
102 break;
103 }
104 } while (known);
105
106 if ((o & O_EXCL) != 0 && m == O_RDONLY) {
107 errno = EINVAL;
108 return (0);
109 }
110
111 *optr = m | o;
112 return (ret);
113 }
114