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flags.c revision 1.12.6.1 
      1 /*	$NetBSD: flags.c,v 1.12.6.1 2002/02/06 23:18:44 nathanw Exp $	*/
      2 
      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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 #if 0
     42 static char sccsid[] = "@(#)flags.c	8.1 (Berkeley) 6/4/93";
     43 #else
     44 __RCSID("$NetBSD: flags.c,v 1.12.6.1 2002/02/06 23:18:44 nathanw Exp $");
     45 #endif
     46 #endif /* LIBC_SCCS and not lint */
     47 
     48 #include <sys/types.h>
     49 #include <assert.h>
     50 #include <fcntl.h>
     51 #include <stdio.h>
     52 #include <errno.h>
     53 #include "reentrant.h"
     54 #include "local.h"
     55 
     56 /*
     57  * Return the (stdio) flags for a given mode.  Store the flags
     58  * to be passed to an open() syscall through *optr.
     59  * Return 0 on error.
     60  */
     61 int
     62 __sflags(mode, optr)
     63 	const char *mode;
     64 	int *optr;
     65 {
     66 	int ret, m, o;
     67 
     68 	_DIAGASSERT(mode != NULL);
     69 
     70 	switch (*mode++) {
     71 
     72 	case 'r':	/* open for reading */
     73 		ret = __SRD;
     74 		m = O_RDONLY;
     75 		o = 0;
     76 		break;
     77 
     78 	case 'w':	/* open for writing */
     79 		ret = __SWR;
     80 		m = O_WRONLY;
     81 		o = O_CREAT | O_TRUNC;
     82 		break;
     83 
     84 	case 'a':	/* open for appending */
     85 		ret = __SWR;
     86 		m = O_WRONLY;
     87 		o = O_CREAT | O_APPEND;
     88 		break;
     89 
     90 	default:	/* illegal mode */
     91 		errno = EINVAL;
     92 		return (0);
     93 	}
     94 
     95 	/*
     96 	 * [rwa]\+ or [rwa]b\+ means read and write
     97 	 * f means open only plain files.
     98 	 */
     99 	for (; *mode; mode++)
    100 		switch (*mode) {
    101 		case '+':
    102 			ret = __SRW;
    103 			m = O_RDWR;
    104 			break;
    105 		case 'f':
    106 			o |= O_NONBLOCK;
    107 			break;
    108 		case 'b':
    109 			break;
    110 		default:	/* We could produce a warning here */
    111 			break;
    112 		}
    113 
    114 	*optr = m | o;
    115 	return (ret);
    116 }
    117