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root/usr/lib/libc/stdio/fopen.c

DEFINITIONS

1. fopen

   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  */
  33 #include <sys/types.h>
  34 #include <sys/stat.h>
  35 #include <fcntl.h>
  36 #include <stdio.h>
  37 #include <errno.h>
  38 #include "local.h"
FILE *
fopen(file, mode)
  42         const char *file;
  43         const char *mode;
  44 {
FILE *fp;
  46         int f;
  47         int flags, oflags;
  49         if ((flags = __sflags(mode, &oflags)) == 0)
  50                 return (NULL);
  51         if ((fp = __sfp()) == NULL)
  52                 return (NULL);
  53         if ((f = open(file, oflags, DEFFILEMODE)) < 0) {
fp->_flags = 0;                 /* release */
  55                 return (NULL);
  56         }
fp->_file = f;
fp->_flags = flags;
  60         /*
  61          * When opening in append mode, even though we use O_APPEND,
  62          * we need to seek to the end so that ftell() gets the right
  63          * answer.  If the user then alters the seek pointer, or
  64          * the file extends, this will fail, but there is not much
  65          * we can do about this.  (We could set __SAPP and check in
  66          * fseek and ftell.)
  67          */
  68         if (oflags & O_APPEND)
  69                 (void) __sseek((void *)fp, (fpos_t)0, SEEK_END);
  70         return (fp);
  71 }