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)
34static 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 */
51int
52__sflags(const char *mode, int *optr)
53{
54	int ret, m, o, known;
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	do {
82		known = 1;
83		switch (*mode++) {
84		case 'b':
85			/* 'b' (binary) is ignored */
86			break;
87		case '+':
88			/* [rwa][b]\+ means read and write */
89			ret = __SRW;
90			m = O_RDWR;
91			break;
92		case 'x':
93			/* 'x' means exclusive (fail if the file exists) */
94			o |= O_EXCL;
95			break;
96		case 'e':
97			/* set close-on-exec */
98			o |= O_CLOEXEC;
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