1 /* $OpenBSD: flags.c,v 1.6 2005/08/08 08:05:36 espie 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 39 /* 40 * Return the (stdio) flags for a given mode. Store the flags 41 * to be passed to an open() syscall through *optr. 42 * Return 0 on error. 43 */ 44 int 45 __sflags(const char *mode, int *optr) 46 { 47 int ret, m, o; 48 49 switch (*mode++) { 50 51 case 'r': /* open for reading */ 52 ret = __SRD; 53 m = O_RDONLY; 54 o = 0; 55 break; 56 57 case 'w': /* open for writing */ 58 ret = __SWR; 59 m = O_WRONLY; 60 o = O_CREAT | O_TRUNC; 61 break; 62 63 case 'a': /* open for appending */ 64 ret = __SWR; 65 m = O_WRONLY; 66 o = O_CREAT | O_APPEND; 67 break; 68 69 default: /* illegal mode */ 70 errno = EINVAL; 71 return (0); 72 } 73 74 /* [rwa]\+ or [rwa]b\+ means read and write */ 75 if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) { 76 ret = __SRW; 77 m = O_RDWR; 78 } 79 *optr = m | o; 80 return (ret); 81 } 82