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 #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 */ 51 int 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 case 'v': 101 /* verify */ 102 o |= O_VERIFY; 103 break; 104 default: 105 known = 0; 106 break; 107 } 108 } while (known); 109 110 if ((o & O_EXCL) != 0 && m == O_RDONLY) { 111 errno = EINVAL; 112 return (0); 113 } 114 115 *optr = m | o; 116 return (ret); 117 } 118