pread.c revision 38465
1/* 2 * $Id$ 3 * From: $NetBSD: pread.c,v 1.2 1997/03/22 01:48:38 thorpej Exp $ 4 */ 5 6/* 7 * Copyright (c) 1996 8 * Matthias Drochner. All rights reserved. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed for the NetBSD Project 21 * by Matthias Drochner. 22 * 4. The name of the author may not be used to endorse or promote products 23 * derived from this software without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 26 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 27 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 28 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 29 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 30 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 31 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 32 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 33 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 34 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 35 * 36 */ 37 38/* read into destination in flat addr space */ 39 40#include <stand.h> 41 42#include "libi386.h" 43 44#ifdef SAVE_MEMORY 45#define BUFSIZE (1*1024) 46#else 47#define BUFSIZE (4*1024) 48#endif 49 50static char buf[BUFSIZE]; 51 52int 53pread(fd, dest, size) 54 int fd; 55 vm_offset_t dest; 56 int size; 57{ 58 int rsize; 59 60 rsize = size; 61 while (rsize > 0) { 62 int count, got; 63 64 count = (rsize < BUFSIZE ? rsize : BUFSIZE); 65 66 got = read(fd, buf, count); 67 if (got < 0) 68 return (-1); 69 70 /* put to physical space */ 71 vpbcopy(buf, dest, got); 72 73 dest += got; 74 rsize -= got; 75 if (got < count) 76 break; /* EOF */ 77 } 78 return (size - rsize); 79} 80