1/*
2 * $NetBSD: pread.c,v 1.2 1997/03/22 01:48:38 thorpej Exp $
3 */
4
5/*-
6 * Copyright (c) 1996
7 *	Matthias Drochner.  All rights reserved.
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. All advertising materials mentioning features or use of this software
18 *    must display the following acknowledgement:
19 *	This product includes software developed for the NetBSD Project
20 *	by Matthias Drochner.
21 * 4. The name of the author may not be used to endorse or promote products
22 *    derived from this software without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34 */
35
36#include <sys/cdefs.h>
37__FBSDID("$FreeBSD: stable/11/stand/i386/libi386/pread.c 119482 2003-08-25 23:28:32Z obrien $");
38
39/* read into destination in flat addr space */
40
41#include <stand.h>
42
43#include "libi386.h"
44
45#ifdef SAVE_MEMORY
46#define BUFSIZE (1*1024)
47#else
48#define BUFSIZE (4*1024)
49#endif
50
51static char     buf[BUFSIZE];
52
53int
54pread(fd, dest, size)
55	int             fd;
56	vm_offset_t         dest;
57	int             size;
58{
59	int             rsize;
60
61	rsize = size;
62	while (rsize > 0) {
63		int             count, got;
64
65		count = (rsize < BUFSIZE ? rsize : BUFSIZE);
66
67		got = read(fd, buf, count);
68		if (got < 0)
69			return (-1);
70
71		/* put to physical space */
72		vpbcopy(buf, dest, got);
73
74		dest += got;
75		rsize -= got;
76		if (got < count)
77			break;	/* EOF */
78	}
79	return (size - rsize);
80}
81