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fopen.c revision 1.7 
      1 /*	$NetBSD: fopen.c,v 1.7 1999/09/16 11:45:27 lukem Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1990, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * This code is derived from software contributed to Berkeley by
      8  * Chris Torek.
      9  *
     10  * Redistribution and use in source and binary forms, with or without
     11  * modification, are permitted provided that the following conditions
     12  * are met:
     13  * 1. Redistributions of source code must retain the above copyright
     14  *    notice, this list of conditions and the following disclaimer.
     15  * 2. Redistributions in binary form must reproduce the above copyright
     16  *    notice, this list of conditions and the following disclaimer in the
     17  *    documentation and/or other materials provided with the distribution.
     18  * 3. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #if defined(LIBC_SCCS) && !defined(lint)
     41 #if 0
     42 static char sccsid[] = "@(#)fopen.c	8.1 (Berkeley) 6/4/93";
     43 #else
     44 __RCSID("$NetBSD: fopen.c,v 1.7 1999/09/16 11:45:27 lukem Exp $");
     45 #endif
     46 #endif /* LIBC_SCCS and not lint */
     47 
     48 #include <sys/types.h>
     49 #include <sys/stat.h>
     50 #include <assert.h>
     51 #include <fcntl.h>
     52 #include <stdio.h>
     53 #include <errno.h>
     54 #include "local.h"
     55 
     56 FILE *
     57 fopen(file, mode)
     58 	const char *file;
     59 	const char *mode;
     60 {
     61 	FILE *fp;
     62 	int f;
     63 	int flags, oflags;
     64 
     65 	_DIAGASSERT(file != NULL);
     66 #ifdef _DIAGNOSTIC
     67 	if (file == NULL)
     68 		return (NULL);
     69 #endif
     70 	if ((flags = __sflags(mode, &oflags)) == 0)
     71 		return (NULL);
     72 	if ((fp = __sfp()) == NULL)
     73 		return (NULL);
     74 	if ((f = open(file, oflags, DEFFILEMODE)) < 0) {
     75 		fp->_flags = 0;			/* release */
     76 		return (NULL);
     77 	}
     78 	fp->_file = f;
     79 	fp->_flags = flags;
     80 	fp->_cookie = fp;
     81 	fp->_read = __sread;
     82 	fp->_write = __swrite;
     83 	fp->_seek = __sseek;
     84 	fp->_close = __sclose;
     85 
     86 	/*
     87 	 * When opening in append mode, even though we use O_APPEND,
     88 	 * we need to seek to the end so that ftell() gets the right
     89 	 * answer.  If the user then alters the seek pointer, or
     90 	 * the file extends, this will fail, but there is not much
     91 	 * we can do about this.  (We could set __SAPP and check in
     92 	 * fseek and ftell.)
     93 	 */
     94 	if (oflags & O_APPEND)
     95 		(void) __sseek((void *)fp, (fpos_t)0, SEEK_END);
     96 	return (fp);
     97 }
     98