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fopen.c revision 1.10 
      1 /*	$NetBSD: fopen.c,v 1.10 2000/11/29 15:30:20 christos 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 1.10 2000/11/29 15:30:20 christos 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 <unistd.h>
     53 #include <stdio.h>
     54 #include <errno.h>
     55 #include "local.h"
     56 
     57 FILE *
     58 fopen(file, mode)
     59 	const char *file;
     60 	const char *mode;
     61 {
     62 	FILE *fp;
     63 	int f;
     64 	int flags, oflags;
     65 
     66 	_DIAGASSERT(file != NULL);
     67 	if ((flags = __sflags(mode, &oflags)) == 0)
     68 		return (NULL);
     69 	if ((fp = __sfp()) == NULL)
     70 		return (NULL);
     71 	if ((f = open(file, oflags, DEFFILEMODE)) < 0)
     72 		goto release;
     73 	if (oflags & O_NONBLOCK) {
     74 		struct stat st;
     75 		if (fstat(f, &st) == -1) {
     76 			int sverrno = errno;
     77 			(void)close(f);
     78 			errno = sverrno;
     79 			goto release;
     80 		}
     81 		if (!S_ISREG(st.st_mode)) {
     82 			(void)close(f);
     83 			errno = EFTYPE;
     84 			goto release;
     85 		}
     86 	}
     87 	fp->_file = f;
     88 	fp->_flags = flags;
     89 	fp->_cookie = fp;
     90 	fp->_read = __sread;
     91 	fp->_write = __swrite;
     92 	fp->_seek = __sseek;
     93 	fp->_close = __sclose;
     94 
     95 	/*
     96 	 * When opening in append mode, even though we use O_APPEND,
     97 	 * we need to seek to the end so that ftell() gets the right
     98 	 * answer.  If the user then alters the seek pointer, or
     99 	 * the file extends, this will fail, but there is not much
    100 	 * we can do about this.  (We could set __SAPP and check in
    101 	 * fseek and ftell.)
    102 	 */
    103 	if (oflags & O_APPEND)
    104 		(void) __sseek((void *)fp, (fpos_t)0, SEEK_END);
    105 	return (fp);
    106 release:
    107 	fp->_flags = 0;			/* release */
    108 	return (NULL);
    109 }
    110