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
38static 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 */
57int
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