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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  */
  36
  37 #if defined(LIBC_SCCS) && !defined(lint)
  38 static char sccsid[] = "@(#)flags.c     8.1 (Berkeley) 6/4/93";
  39 #endif /* LIBC_SCCS and not lint */
  40 #include <sys/cdefs.h>
  41 __FBSDID("$FreeBSD: src/lib/libc/stdio/flags.c,v 1.9 2002/03/22 21:53:04 obrien Exp $");
  42
  43 #include <sys/types.h>
  44 #include <sys/file.h>
  45 #include <stdio.h>
  46 #include <errno.h>
  47
  48 #include "local.h"
  49
  50 /*
  51  * Return the (stdio) flags for a given mode.  Store the flags
  52  * to be passed to an _open() syscall through *optr.
  53  * Return 0 on error.
  54  */
  55 int
  56 __sflags(mode, optr)
  57         const char *mode;
  58         int *optr;
  59 {
  60         int ret, m, o;
  61
  62         switch (*mode++) {
  63
  64         case 'r':       /* open for reading */
  65                 ret = __SRD;
  66                 m = O_RDONLY;
  67                 o = 0;
  68                 break;
  69
  70         case 'w':       /* open for writing */
  71                 ret = __SWR;
  72                 m = O_WRONLY;
  73                 o = O_CREAT | O_TRUNC;
  74                 break;
  75
  76         case 'a':       /* open for appending */
  77                 ret = __SWR;
  78                 m = O_WRONLY;
  79                 o = O_CREAT | O_APPEND;
  80                 break;
  81
  82         default:        /* illegal mode */
  83                 errno = EINVAL;
  84                 return (0);
  85         }
  86
  87         /* [rwa]\+ or [rwa]b\+ means read and write */
  88         if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) {
  89                 ret = __SRW;
  90                 m = O_RDWR;
  91         }
  92         *optr = m | o;
  93         return (ret);
  94 }