stdio/FreeBSD/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
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)flags.c     8.1 (Berkeley) 6/4/93";
  35 #endif /* LIBC_SCCS and not lint */
  36 #include <sys/cdefs.h>
  37 __FBSDID("$FreeBSD: src/lib/libc/stdio/flags.c,v 1.10 2007/01/09 00:28:06 imp Exp $");
  38
  39 #include <sys/types.h>
  40 #include <sys/file.h>
  41 #include <stdio.h>
  42 #include <errno.h>
  43
  44 #include "local.h"
  45
  46 /*
  47  * Return the (stdio) flags for a given mode.  Store the flags
  48  * to be passed to an _open() syscall through *optr.
  49  * Return 0 on error.
  50  */
  51 int
  52 __sflags(mode, optr)
  53         const char *mode;
  54         int *optr;
  55 {
  56         int ret, m, o;
  57
  58         switch (*mode++) {
  59
  60         case 'r':       /* open for reading */
  61                 ret = __SRD;
  62                 m = O_RDONLY;
  63                 o = 0;
  64                 break;
  65
  66         case 'w':       /* open for writing */
  67                 ret = __SWR;
  68                 m = O_WRONLY;
  69                 o = O_CREAT | O_TRUNC;
  70                 break;
  71
  72         case 'a':       /* open for appending */
  73                 ret = __SWR;
  74                 m = O_WRONLY;
  75                 o = O_CREAT | O_APPEND;
  76                 break;
  77
  78         default:        /* illegal mode */
  79                 errno = EINVAL;
  80                 return (0);
  81         }
  82
  83         /* [rwa]\+ or [rwa]b\+ means read and write */
  84         if (*mode == 'b')
  85                 mode++;
  86         if (*mode == '+') {
  87                 ret = __SRW;
  88                 m = O_RDWR;
  89                 mode++;
  90                 if (*mode == 'b')
  91                         mode++;
  92         }
  93         if (*mode == 'x')
  94                 o |= O_EXCL;
  95         *optr = m | o;
  96         return (ret);
  97 }