1/*	$OpenBSD: flags.c,v 1.8 2014/08/31 02:21:18 guenther Exp $ */
2/*-
3 * Copyright (c) 1990, 1993
4 *	The Regents of the University of California.  All rights reserved.
5 *
6 * This code is derived from software contributed to Berkeley by
7 * Chris Torek.
8 *
9 * Redistribution and use in source and binary forms, with or without
10 * modification, are permitted provided that the following conditions
11 * are met:
12 * 1. Redistributions of source code must retain the above copyright
13 *    notice, this list of conditions and the following disclaimer.
14 * 2. Redistributions in binary form must reproduce the above copyright
15 *    notice, this list of conditions and the following disclaimer in the
16 *    documentation and/or other materials provided with the distribution.
17 * 3. Neither the name of the University nor the names of its contributors
18 *    may be used to endorse or promote products derived from this software
19 *    without specific prior written permission.
20 *
21 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
22 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
24 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
31 * SUCH DAMAGE.
32 */
33
34#include <sys/types.h>
35#include <sys/file.h>
36#include <stdio.h>
37#include <errno.h>
38#include "local.h"
39
40/*
41 * Return the (stdio) flags for a given mode.  Store the flags
42 * to be passed to an open() syscall through *optr.
43 * Return 0 on error.
44 */
45int
46__sflags(const char *mode, int *optr)
47{
48	int ret, m, o;
49
50	switch (*mode++) {
51
52	case 'r':	/* open for reading */
53		ret = __SRD;
54		m = O_RDONLY;
55		o = 0;
56		break;
57
58	case 'w':	/* open for writing */
59		ret = __SWR;
60		m = O_WRONLY;
61		o = O_CREAT | O_TRUNC;
62		break;
63
64	case 'a':	/* open for appending */
65		ret = __SWR;
66		m = O_WRONLY;
67		o = O_CREAT | O_APPEND;
68		break;
69
70	default:	/* illegal mode */
71		errno = EINVAL;
72		return (0);
73	}
74
75	while (*mode != '\0')
76		switch (*mode++) {
77		case 'b':
78			break;
79		case '+':
80			ret = __SRW;
81			m = O_RDWR;
82			break;
83		case 'e':
84			o |= O_CLOEXEC;
85			break;
86		case 'x':
87			if (o & O_CREAT)
88				o |= O_EXCL;
89			break;
90		default:
91			/*
92			 * Lots of software passes other extension mode
93			 * letters, like Window's 't'
94			 */
95#if 0
96			errno = EINVAL;
97			return (0);
98#else
99			break;
100#endif
101		}
102
103	*optr = m | o;
104	return (ret);
105}
106