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) 34 static 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 */ 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 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