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stdio.c revision 1.19 
      1 /*	$NetBSD: stdio.c,v 1.19 2012/03/15 18:22:30 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. Neither the name of the University nor the names of its contributors
     19  *    may be used to endorse or promote products derived from this software
     20  *    without specific prior written permission.
     21  *
     22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     32  * SUCH DAMAGE.
     33  */
     34 
     35 #include <sys/cdefs.h>
     36 #if defined(LIBC_SCCS) && !defined(lint)
     37 #if 0
     38 static char sccsid[] = "@(#)stdio.c	8.1 (Berkeley) 6/4/93";
     39 #else
     40 __RCSID("$NetBSD: stdio.c,v 1.19 2012/03/15 18:22:30 christos Exp $");
     41 #endif
     42 #endif /* LIBC_SCCS and not lint */
     43 
     44 #include "namespace.h"
     45 
     46 #include <assert.h>
     47 #include <errno.h>
     48 #include <fcntl.h>
     49 #include <stdio.h>
     50 #include <unistd.h>
     51 
     52 #include "reentrant.h"
     53 #include "local.h"
     54 
     55 /*
     56  * Small standard I/O/seek/close functions.
     57  * These maintain the `known seek offset' for seek optimisation.
     58  */
     59 int
     60 __sread(void *cookie, char *buf, int n)
     61 {
     62 	FILE *fp = cookie;
     63 	ssize_t ret;
     64 
     65 	_DIAGASSERT(fp != NULL);
     66 	_DIAGASSERT(buf != NULL);
     67 
     68 	ret = read(__sfileno(fp), buf, (size_t)n);
     69 	/* if the read succeeded, update the current offset */
     70 	if (ret >= 0)
     71 		fp->_offset += ret;
     72 	else
     73 		fp->_flags &= ~__SOFF;	/* paranoia */
     74 
     75 	return (int)ret;
     76 }
     77 
     78 int
     79 __swrite(void *cookie, char const *buf, int n)
     80 {
     81 	FILE *fp = cookie;
     82 
     83 	_DIAGASSERT(cookie != NULL);
     84 	_DIAGASSERT(buf != NULL);
     85 
     86 	if (fp->_flags & __SAPP)
     87 		(void) lseek(__sfileno(fp), (off_t)0, SEEK_END);
     88 	fp->_flags &= ~__SOFF;	/* in case FAPPEND mode is set */
     89 	return (int)write(__sfileno(fp), buf, (size_t)n);
     90 }
     91 
     92 off_t
     93 __sseek(void *cookie, off_t offset, int whence)
     94 {
     95 	FILE *fp = cookie;
     96 	off_t ret;
     97 
     98 	_DIAGASSERT(fp != NULL);
     99 
    100 	ret = lseek(__sfileno(fp), offset, whence);
    101 	if (ret == -1L)
    102 		fp->_flags &= ~__SOFF;
    103 	else {
    104 		fp->_flags |= __SOFF;
    105 		fp->_offset = ret;
    106 	}
    107 	return ret;
    108 }
    109 
    110 int
    111 __sclose(cookie)
    112 	void *cookie;
    113 {
    114 
    115 	_DIAGASSERT(cookie != NULL);
    116 
    117 	return close(__sfileno((FILE *)cookie));
    118 }
    119