lib/libc/stdio/flags.c

   1 /*      $NetBSD: flags.c,v 1.17 2012/11/15 03:50:36 christos 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. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #if defined(LIBC_SCCS) && !defined(lint)
  37 #if 0
  38 static char sccsid[] = "@(#)flags.c     8.1 (Berkeley) 6/4/93";
  39 #else
  40 __RCSID("$NetBSD: flags.c,v 1.17 2012/11/15 03:50:36 christos Exp $");
  41 #endif
  42 #endif /* LIBC_SCCS and not lint */
  43
  44 #include <sys/types.h>
  45 #include <assert.h>
  46 #include <fcntl.h>
  47 #include <stdio.h>
  48 #include <errno.h>
  49 #include "reentrant.h"
  50 #include "local.h"
  51
  52 /*
  53  * Return the (stdio) flags for a given mode.  Store the flags
  54  * to be passed to an open() syscall through *optr.
  55  * Return 0 on error.
  56  */
  57 int
  58 __sflags(const char *mode, int *optr)
  59 {
  60         int ret, m, o;
  61
  62         _DIAGASSERT(mode != NULL);
  63
  64         switch (*mode++) {
  65
  66         case 'r':       /* open for reading */
  67                 ret = __SRD;
  68                 m = O_RDONLY;
  69                 o = 0;
  70                 break;
  71
  72         case 'w':       /* open for writing */
  73                 ret = __SWR;
  74                 m = O_WRONLY;
  75                 o = O_CREAT | O_TRUNC;
  76                 break;
  77
  78         case 'a':       /* open for appending */
  79                 ret = __SWR;
  80                 m = O_WRONLY;
  81                 o = O_CREAT | O_APPEND;
  82                 break;
  83
  84         default:        /* illegal mode */
  85                 errno = EINVAL;
  86                 return 0;
  87         }
  88
  89         /*
  90          * [rwa]\+ or [rwa]b\+ means read and write
  91          * f means open only plain files,
  92          * e means set close on exec.
  93          * x means exclusive open.
  94          */
  95         for (; *mode; mode++)
  96                 switch (*mode) {
  97                 case '+':
  98                         ret = __SRW;
  99                         m = O_RDWR;
 100                         break;
 101                 case 'f':
 102                         o |= O_NONBLOCK;
 103                         break;
 104                 case 'e':
 105                         o |= O_CLOEXEC;
 106                         break;
 107                 case 'x':
 108                         o |= O_EXCL;
 109                         break;
 110                 case 'b':
 111                         break;
 112                 default:        /* We could produce a warning here */
 113                         break;
 114                 }
 115
 116         *optr = m | o;
 117         return ret;
 118 }