1*5e073c03Smanu /* $NetBSD: pread.c,v 1.8 2019/09/13 02:19:46 manu Exp $ */
2816bb961Sperry
3816bb961Sperry /*
4816bb961Sperry * Copyright (c) 1996
5816bb961Sperry * Matthias Drochner. All rights reserved.
6816bb961Sperry *
7816bb961Sperry * Redistribution and use in source and binary forms, with or without
8816bb961Sperry * modification, are permitted provided that the following conditions
9816bb961Sperry * are met:
10816bb961Sperry * 1. Redistributions of source code must retain the above copyright
11816bb961Sperry * notice, this list of conditions and the following disclaimer.
12816bb961Sperry * 2. Redistributions in binary form must reproduce the above copyright
13816bb961Sperry * notice, this list of conditions and the following disclaimer in the
14816bb961Sperry * documentation and/or other materials provided with the distribution.
15816bb961Sperry *
16816bb961Sperry * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
17816bb961Sperry * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
18816bb961Sperry * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
19816bb961Sperry * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
20816bb961Sperry * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
21816bb961Sperry * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
22816bb961Sperry * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
23816bb961Sperry * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
24816bb961Sperry * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
25816bb961Sperry * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
26816bb961Sperry *
27816bb961Sperry */
28816bb961Sperry
29816bb961Sperry /* read into destination in flat addr space */
30816bb961Sperry
31816bb961Sperry #include <lib/libsa/stand.h>
32816bb961Sperry
33816bb961Sperry #include "libi386.h"
34816bb961Sperry
35816bb961Sperry #ifdef SAVE_MEMORY
36816bb961Sperry #define BUFSIZE (1*1024)
37816bb961Sperry #else
38816bb961Sperry #define BUFSIZE (4*1024)
39816bb961Sperry #endif
40816bb961Sperry
4181acacd7Sdsl static char *buf;
42816bb961Sperry
439fa73628Schristos ssize_t
pread(int fd,void * dest,size_t size)44334f5e8fSchristos pread(int fd, void *dest, size_t size)
45816bb961Sperry {
46*5e073c03Smanu size_t rsize;
47816bb961Sperry
4881acacd7Sdsl if (!buf)
4981acacd7Sdsl buf = alloc(BUFSIZE);
5081acacd7Sdsl
51816bb961Sperry rsize = size;
52816bb961Sperry while (rsize > 0) {
53*5e073c03Smanu size_t count;
54*5e073c03Smanu ssize_t got;
55816bb961Sperry
56816bb961Sperry count = (rsize < BUFSIZE ? rsize : BUFSIZE);
57816bb961Sperry
58816bb961Sperry got = read(fd, buf, count);
59f07be036Sthorpej if (got < 0)
60334f5e8fSchristos return -1;
61816bb961Sperry
62816bb961Sperry /* put to physical space */
63816bb961Sperry vpbcopy(buf, dest, got);
64816bb961Sperry
65816bb961Sperry dest += got;
66816bb961Sperry rsize -= got;
67f07be036Sthorpej if (got < count)
68f07be036Sthorpej break; /* EOF */
69816bb961Sperry }
70334f5e8fSchristos return size - rsize;
71816bb961Sperry }
72