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 #if defined(LIBC_SCCS) && !defined(lint) 36 static char sccsid[] = "@(#)flags.c 8.1 (Berkeley) 6/4/93"; 37 #endif /* LIBC_SCCS and not lint */ 38 #include <sys/cdefs.h> 39 __FBSDID("$FreeBSD$"); 40 41 #include <sys/types.h> 42 #include <sys/file.h> 43 #include <stdio.h> 44 #include <errno.h> 45 46 #include "local.h" 47 48 /* 49 * Return the (stdio) flags for a given mode. Store the flags 50 * to be passed to an _open() syscall through *optr. 51 * Return 0 on error. 52 */ 53 int 54 __sflags(const char *mode, int *optr) 55 { 56 int ret, m, o, known; 57 58 switch (*mode++) { 59 60 case 'r': /* open for reading */ 61 ret = __SRD; 62 m = O_RDONLY; 63 o = 0; 64 break; 65 66 case 'w': /* open for writing */ 67 ret = __SWR; 68 m = O_WRONLY; 69 o = O_CREAT | O_TRUNC; 70 break; 71 72 case 'a': /* open for appending */ 73 ret = __SWR; 74 m = O_WRONLY; 75 o = O_CREAT | O_APPEND; 76 break; 77 78 default: /* illegal mode */ 79 errno = EINVAL; 80 return (0); 81 } 82 83 do { 84 known = 1; 85 switch (*mode++) { 86 case 'b': 87 /* 'b' (binary) is ignored */ 88 break; 89 case '+': 90 /* [rwa][b]\+ means read and write */ 91 ret = __SRW; 92 m = O_RDWR; 93 break; 94 case 'x': 95 /* 'x' means exclusive (fail if the file exists) */ 96 o |= O_EXCL; 97 break; 98 case 'e': 99 /* set close-on-exec */ 100 o |= O_CLOEXEC; 101 break; 102 case 'v': 103 /* verify */ 104 o |= O_VERIFY; 105 break; 106 default: 107 known = 0; 108 break; 109 } 110 } while (known); 111 112 if ((o & O_EXCL) != 0 && m == O_RDONLY) { 113 errno = EINVAL; 114 return (0); 115 } 116 117 *optr = m | o; 118 return (ret); 119 } 120