lib/libc/stdio/flags.c

   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  * 4. 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  * @(#)flags.c  8.1 (Berkeley) 6/4/93
  33  * $FreeBSD: src/lib/libc/stdio/flags.c,v 1.10 2007/01/09 00:28:06 imp Exp $
  34  * $DragonFly: src/lib/libc/stdio/flags.c,v 1.5 2005/01/31 22:29:40 dillon Exp $
  35  */
  36
  37 #include <sys/types.h>
  38 #include <sys/file.h>
  39 #include <stdio.h>
  40 #include <errno.h>
  41
  42 #include "local.h"
  43
  44 /*
  45  * Return the (stdio) flags for a given mode.  Store the flags
  46  * to be passed to an _open() syscall through *optr.
  47  * Return 0 on error.
  48  */
  49 int
  50 __sflags(const char *mode, int *optr)
  51 {
  52         int ret, m, o;
  53
  54         switch (*mode++) {
  55
  56         case 'r':       /* open for reading */
  57                 ret = __SRD;
  58                 m = O_RDONLY;
  59                 o = 0;
  60                 break;
  61
  62         case 'w':       /* open for writing */
  63                 ret = __SWR;
  64                 m = O_WRONLY;
  65                 o = O_CREAT | O_TRUNC;
  66                 break;
  67
  68         case 'a':       /* open for appending */
  69                 ret = __SWR;
  70                 m = O_WRONLY;
  71                 o = O_CREAT | O_APPEND;
  72                 break;
  73
  74         default:        /* illegal mode */
  75                 errno = EINVAL;
  76                 return (0);
  77         }
  78
  79         /* [rwa]\+ or [rwa]b\+ means read and write */
  80         if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) {
  81                 ret = __SRW;
  82                 m = O_RDWR;
  83         }
  84         *optr = m | o;
  85         return (ret);
  86 }