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      1 /*	$OpenBSD: flags.c,v 1.8 2014/08/31 02:21:18 guenther 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 #include "local.h"
     39 
     40 /*
     41  * Return the (stdio) flags for a given mode.  Store the flags
     42  * to be passed to an open() syscall through *optr.
     43  * Return 0 on error.
     44  */
     45 int
     46 __sflags(const char *mode, int *optr)
     47 {
     48 	int ret, m, o;
     49 
     50 	switch (*mode++) {
     51 
     52 	case 'r':	/* open for reading */
     53 		ret = __SRD;
     54 		m = O_RDONLY;
     55 		o = 0;
     56 		break;
     57 
     58 	case 'w':	/* open for writing */
     59 		ret = __SWR;
     60 		m = O_WRONLY;
     61 		o = O_CREAT | O_TRUNC;
     62 		break;
     63 
     64 	case 'a':	/* open for appending */
     65 		ret = __SWR;
     66 		m = O_WRONLY;
     67 		o = O_CREAT | O_APPEND;
     68 		break;
     69 
     70 	default:	/* illegal mode */
     71 		errno = EINVAL;
     72 		return (0);
     73 	}
     74 
     75 	while (*mode != '\0')
     76 		switch (*mode++) {
     77 		case 'b':
     78 			break;
     79 		case '+':
     80 			ret = __SRW;
     81 			m = O_RDWR;
     82 			break;
     83 		case 'e':
     84 			o |= O_CLOEXEC;
     85 			break;
     86 		case 'x':
     87 			if (o & O_CREAT)
     88 				o |= O_EXCL;
     89 			break;
     90 		default:
     91 			/*
     92 			 * Lots of software passes other extension mode
     93 			 * letters, like Window's 't'
     94 			 */
     95 #if 0
     96 			errno = EINVAL;
     97 			return (0);
     98 #else
     99 			break;
    100 #endif
    101 		}
    102 
    103 	*optr = m | o;
    104 	return (ret);
    105 }
    106