xref: /titanic_52/usr/src/boot/sys/boot/i386/libi386/pread.c (revision 4a5d661a82b942b6538acd26209d959ce98b593a)
1*4a5d661aSToomas Soome /*
2*4a5d661aSToomas Soome  * $NetBSD: pread.c,v 1.2 1997/03/22 01:48:38 thorpej Exp $
3*4a5d661aSToomas Soome  */
4*4a5d661aSToomas Soome 
5*4a5d661aSToomas Soome /*-
6*4a5d661aSToomas Soome  * Copyright (c) 1996
7*4a5d661aSToomas Soome  *	Matthias Drochner.  All rights reserved.
8*4a5d661aSToomas Soome  *
9*4a5d661aSToomas Soome  * Redistribution and use in source and binary forms, with or without
10*4a5d661aSToomas Soome  * modification, are permitted provided that the following conditions
11*4a5d661aSToomas Soome  * are met:
12*4a5d661aSToomas Soome  * 1. Redistributions of source code must retain the above copyright
13*4a5d661aSToomas Soome  *    notice, this list of conditions and the following disclaimer.
14*4a5d661aSToomas Soome  * 2. Redistributions in binary form must reproduce the above copyright
15*4a5d661aSToomas Soome  *    notice, this list of conditions and the following disclaimer in the
16*4a5d661aSToomas Soome  *    documentation and/or other materials provided with the distribution.
17*4a5d661aSToomas Soome  * 3. All advertising materials mentioning features or use of this software
18*4a5d661aSToomas Soome  *    must display the following acknowledgement:
19*4a5d661aSToomas Soome  *	This product includes software developed for the NetBSD Project
20*4a5d661aSToomas Soome  *	by Matthias Drochner.
21*4a5d661aSToomas Soome  * 4. The name of the author may not be used to endorse or promote products
22*4a5d661aSToomas Soome  *    derived from this software without specific prior written permission.
23*4a5d661aSToomas Soome  *
24*4a5d661aSToomas Soome  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
25*4a5d661aSToomas Soome  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
26*4a5d661aSToomas Soome  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
27*4a5d661aSToomas Soome  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
28*4a5d661aSToomas Soome  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
29*4a5d661aSToomas Soome  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
30*4a5d661aSToomas Soome  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
31*4a5d661aSToomas Soome  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
32*4a5d661aSToomas Soome  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
33*4a5d661aSToomas Soome  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
34*4a5d661aSToomas Soome  */
35*4a5d661aSToomas Soome 
36*4a5d661aSToomas Soome #include <sys/cdefs.h>
37*4a5d661aSToomas Soome __FBSDID("$FreeBSD$");
38*4a5d661aSToomas Soome 
39*4a5d661aSToomas Soome /* read into destination in flat addr space */
40*4a5d661aSToomas Soome 
41*4a5d661aSToomas Soome #include <stand.h>
42*4a5d661aSToomas Soome 
43*4a5d661aSToomas Soome #include "libi386.h"
44*4a5d661aSToomas Soome 
45*4a5d661aSToomas Soome #ifdef SAVE_MEMORY
46*4a5d661aSToomas Soome #define BUFSIZE (1*1024)
47*4a5d661aSToomas Soome #else
48*4a5d661aSToomas Soome #define BUFSIZE (4*1024)
49*4a5d661aSToomas Soome #endif
50*4a5d661aSToomas Soome 
51*4a5d661aSToomas Soome static char     buf[BUFSIZE];
52*4a5d661aSToomas Soome 
53*4a5d661aSToomas Soome int
54*4a5d661aSToomas Soome pread(fd, dest, size)
55*4a5d661aSToomas Soome 	int             fd;
56*4a5d661aSToomas Soome 	vm_offset_t         dest;
57*4a5d661aSToomas Soome 	int             size;
58*4a5d661aSToomas Soome {
59*4a5d661aSToomas Soome 	int             rsize;
60*4a5d661aSToomas Soome 
61*4a5d661aSToomas Soome 	rsize = size;
62*4a5d661aSToomas Soome 	while (rsize > 0) {
63*4a5d661aSToomas Soome 		int             count, got;
64*4a5d661aSToomas Soome 
65*4a5d661aSToomas Soome 		count = (rsize < BUFSIZE ? rsize : BUFSIZE);
66*4a5d661aSToomas Soome 
67*4a5d661aSToomas Soome 		got = read(fd, buf, count);
68*4a5d661aSToomas Soome 		if (got < 0)
69*4a5d661aSToomas Soome 			return (-1);
70*4a5d661aSToomas Soome 
71*4a5d661aSToomas Soome 		/* put to physical space */
72*4a5d661aSToomas Soome 		vpbcopy(buf, dest, got);
73*4a5d661aSToomas Soome 
74*4a5d661aSToomas Soome 		dest += got;
75*4a5d661aSToomas Soome 		rsize -= got;
76*4a5d661aSToomas Soome 		if (got < count)
77*4a5d661aSToomas Soome 			break;	/* EOF */
78*4a5d661aSToomas Soome 	}
79*4a5d661aSToomas Soome 	return (size - rsize);
80*4a5d661aSToomas Soome }
81