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("$FreeBSD$");
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
51 static char buf[BUFSIZE];
52
53 int
pread(fd,dest,size)54 pread(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