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 rcsid[] = "$OpenBSD: flags.c,v 1.5 2004/09/28 18:12:44 otto Exp $"; 35 #endif /* LIBC_SCCS and not lint */ 36 37 #include <sys/types.h> 38 #include <sys/file.h> 39 #include <stdio.h> 40 #include <errno.h> 41 42 /* 43 * Return the (stdio) flags for a given mode. Store the flags 44 * to be passed to an open() syscall through *optr. 45 * Return 0 on error. 46 */ 47 int 48 __sflags(const char *mode, int *optr) 49 { 50 int ret, m, o; 51 52 switch (*mode++) { 53 54 case 'r': /* open for reading */ 55 ret = __SRD; 56 m = O_RDONLY; 57 o = 0; 58 break; 59 60 case 'w': /* open for writing */ 61 ret = __SWR; 62 m = O_WRONLY; 63 o = O_CREAT | O_TRUNC; 64 break; 65 66 case 'a': /* open for appending */ 67 ret = __SWR; 68 m = O_WRONLY; 69 o = O_CREAT | O_APPEND; 70 break; 71 72 default: /* illegal mode */ 73 errno = EINVAL; 74 return (0); 75 } 76 77 /* [rwa]\+ or [rwa]b\+ means read and write */ 78 if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) { 79 ret = __SRW; 80 m = O_RDWR; 81 } 82 *optr = m | o; 83 return (ret); 84 } 85