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  * 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  * @(#)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         /*
  55          * Base mode
  56          */
  57         switch (*mode) {
  58         case 'r':
  59                 /*
  60                  * Reading
  61                  */
  62                 ret = __SRD;
  63                 m = O_RDONLY;
  64                 o = 0;
  65                 break;
  66         case 'w':
  67                 /*
  68                  * Writing
  69                  */
  70                 ret = __SWR;
  71                 m = O_WRONLY;
  72                 o = O_CREAT | O_TRUNC;
  73                 break;
  74         case 'a':
  75                 /*
  76                  * Append
  77                  */
  78                 ret = __SWR;
  79                 m = O_WRONLY;
  80                 o = O_CREAT | O_APPEND;
  81                 break;
  82         default:
  83                 /*
  84                  * Illegal primary mode, fail.
  85                  */
  86                 errno = EINVAL;
  87                 return (0);
  88         }
  89
  90         /*
  91          * Parse modifiers
  92          */
  93         for (++mode; *mode; ++mode) {
  94                 switch(*mode) {
  95                 case '+':
  96                         /*
  97                          * R+W
  98                          */
  99                         ret = __SRW;
 100                         m = O_RDWR;
 101                         break;
 102                 case 'b':
 103                         /*
 104                          * Binary (inherent, no special treatment)
 105                          */
 106                         break;
 107                 case 'x':
 108                         /*
 109                          * Exclusive.  Only make sense if opening for
 110                          * r+w, w, or a, but let open() deal with
 111                          * any issues (make behavior the same as glibc).
 112                          */
 113                         o |= O_EXCL;
 114                         break;
 115                 case 'e':
 116                         o |= O_CLOEXEC;
 117                         break;
 118                 default:
 119                         /* ignore unrecognized flag */
 120                         break;
 121                 }
 122         }
 123         *optr = m | o;
 124
 125         return (ret);
 126 }