1*58a2b000SEvgeniy Ivanov /* $NetBSD: pread.c,v 1.7 2008/12/14 17:03:43 christos Exp $ */
2*58a2b000SEvgeniy Ivanov
3*58a2b000SEvgeniy Ivanov /*
4*58a2b000SEvgeniy Ivanov * Copyright (c) 1996
5*58a2b000SEvgeniy Ivanov * Matthias Drochner. All rights reserved.
6*58a2b000SEvgeniy Ivanov *
7*58a2b000SEvgeniy Ivanov * Redistribution and use in source and binary forms, with or without
8*58a2b000SEvgeniy Ivanov * modification, are permitted provided that the following conditions
9*58a2b000SEvgeniy Ivanov * are met:
10*58a2b000SEvgeniy Ivanov * 1. Redistributions of source code must retain the above copyright
11*58a2b000SEvgeniy Ivanov * notice, this list of conditions and the following disclaimer.
12*58a2b000SEvgeniy Ivanov * 2. Redistributions in binary form must reproduce the above copyright
13*58a2b000SEvgeniy Ivanov * notice, this list of conditions and the following disclaimer in the
14*58a2b000SEvgeniy Ivanov * documentation and/or other materials provided with the distribution.
15*58a2b000SEvgeniy Ivanov *
16*58a2b000SEvgeniy Ivanov * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17*58a2b000SEvgeniy Ivanov * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18*58a2b000SEvgeniy Ivanov * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19*58a2b000SEvgeniy Ivanov * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20*58a2b000SEvgeniy Ivanov * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21*58a2b000SEvgeniy Ivanov * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22*58a2b000SEvgeniy Ivanov * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23*58a2b000SEvgeniy Ivanov * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24*58a2b000SEvgeniy Ivanov * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25*58a2b000SEvgeniy Ivanov * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26*58a2b000SEvgeniy Ivanov *
27*58a2b000SEvgeniy Ivanov */
28*58a2b000SEvgeniy Ivanov
29*58a2b000SEvgeniy Ivanov /* read into destination in flat addr space */
30*58a2b000SEvgeniy Ivanov
31*58a2b000SEvgeniy Ivanov #include <lib/libsa/stand.h>
32*58a2b000SEvgeniy Ivanov
33*58a2b000SEvgeniy Ivanov #include "libi386.h"
34*58a2b000SEvgeniy Ivanov
35*58a2b000SEvgeniy Ivanov #ifdef SAVE_MEMORY
36*58a2b000SEvgeniy Ivanov #define BUFSIZE (1*1024)
37*58a2b000SEvgeniy Ivanov #else
38*58a2b000SEvgeniy Ivanov #define BUFSIZE (4*1024)
39*58a2b000SEvgeniy Ivanov #endif
40*58a2b000SEvgeniy Ivanov
41*58a2b000SEvgeniy Ivanov static char *buf;
42*58a2b000SEvgeniy Ivanov
43*58a2b000SEvgeniy Ivanov ssize_t
pread(int fd,void * dest,size_t size)44*58a2b000SEvgeniy Ivanov pread(int fd, void *dest, size_t size)
45*58a2b000SEvgeniy Ivanov {
46*58a2b000SEvgeniy Ivanov int rsize;
47*58a2b000SEvgeniy Ivanov
48*58a2b000SEvgeniy Ivanov if (!buf)
49*58a2b000SEvgeniy Ivanov buf = alloc(BUFSIZE);
50*58a2b000SEvgeniy Ivanov
51*58a2b000SEvgeniy Ivanov rsize = size;
52*58a2b000SEvgeniy Ivanov while (rsize > 0) {
53*58a2b000SEvgeniy Ivanov int count, got;
54*58a2b000SEvgeniy Ivanov
55*58a2b000SEvgeniy Ivanov count = (rsize < BUFSIZE ? rsize : BUFSIZE);
56*58a2b000SEvgeniy Ivanov
57*58a2b000SEvgeniy Ivanov got = read(fd, buf, count);
58*58a2b000SEvgeniy Ivanov if (got < 0)
59*58a2b000SEvgeniy Ivanov return -1;
60*58a2b000SEvgeniy Ivanov
61*58a2b000SEvgeniy Ivanov /* put to physical space */
62*58a2b000SEvgeniy Ivanov vpbcopy(buf, dest, got);
63*58a2b000SEvgeniy Ivanov
64*58a2b000SEvgeniy Ivanov dest += got;
65*58a2b000SEvgeniy Ivanov rsize -= got;
66*58a2b000SEvgeniy Ivanov if (got < count)
67*58a2b000SEvgeniy Ivanov break; /* EOF */
68*58a2b000SEvgeniy Ivanov }
69*58a2b000SEvgeniy Ivanov return size - rsize;
70*58a2b000SEvgeniy Ivanov }
71