gonzui

    1: /*      $OpenBSD: flags.c,v 1.6 2005/08/08 08:05:36 espie Exp $ */
    2: /*-
    3:  * Copyright (c) 1990, 1993
    4:  *      The Regents of the University of California.  All rights reserved.
    5:  *
    6:  * This code is derived from software contributed to Berkeley by
    7:  * Chris Torek.
    8:  *
    9:  * Redistribution and use in source and binary forms, with or without
   10:  * modification, are permitted provided that the following conditions
   11:  * are met:
   12:  * 1. Redistributions of source code must retain the above copyright
   13:  *    notice, this list of conditions and the following disclaimer.
   14:  * 2. Redistributions in binary form must reproduce the above copyright
   15:  *    notice, this list of conditions and the following disclaimer in the
   16:  *    documentation and/or other materials provided with the distribution.
   17:  * 3. Neither the name of the University nor the names of its contributors
   18:  *    may be used to endorse or promote products derived from this software
   19:  *    without specific prior written permission.
   20:  *
   21:  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
   22:  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   23:  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   24:  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
   25:  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   26:  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   27:  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   28:  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   29:  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   30:  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   31:  * SUCH DAMAGE.
   32:  */
   33: 
   34: #include <sys/types.h>
   35: #include <sys/file.h>
   36: #include <stdio.h>
   37: #include <errno.h>
   38: 
   39: /*
   40:  * Return the (stdio) flags for a given mode.  Store the flags
   41:  * to be passed to an open() syscall through *optr.
   42:  * Return 0 on error.
   43:  */
   44: int
   45: __sflags(const char *mode, int *optr)
   46: {
   47:         int ret, m, o;
   48: 
   49:         switch (*mode++) {
   50: 
   51:         case 'r':      /* open for reading */
   52:                 ret = __SRD;
   53:                 m = O_RDONLY;
   54:                 o = 0;
   55:                 break;
   56: 
   57:         case 'w':      /* open for writing */
   58:                 ret = __SWR;
   59:                 m = O_WRONLY;
   60:                 o = O_CREAT | O_TRUNC;
   61:                 break;
   62: 
   63:         case 'a':      /* open for appending */
   64:                 ret = __SWR;
   65:                 m = O_WRONLY;
   66:                 o = O_CREAT | O_APPEND;
   67:                 break;
   68: 
   69:         default:       /* illegal mode */
   70:                 /*errno = EINVAL*/;
   71:                 return (0);
   72:         }
   73: 
   74:         /* [rwa]\+ or [rwa]b\+ means read and write */
   75:         if (*mode == '+' || (*mode == 'b' && mode[1] == '+')) {
   76:                 ret = __SRW;
   77:                 m = O_RDWR;
   78:         }
   79:         *optr = m | o;
   80:         return (ret);
   81: }