1 /* $NetBSD: pread.c,v 1.3 1999/01/28 20:22:32 christos Exp $ */ 2 3 /* 4 * Copyright (c) 1996 5 * Matthias Drochner. All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 3. All advertising materials mentioning features or use of this software 16 * must display the following acknowledgement: 17 * This product includes software developed for the NetBSD Project 18 * by Matthias Drochner. 19 * 4. The name of the author may not be used to endorse or promote products 20 * derived from this software without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 23 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 24 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 25 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 27 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 31 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 * 33 */ 34 35 /* read into destination in flat addr space */ 36 37 #include <lib/libsa/stand.h> 38 39 #include "libi386.h" 40 41 #ifdef SAVE_MEMORY 42 #define BUFSIZE (1*1024) 43 #else 44 #define BUFSIZE (4*1024) 45 #endif 46 47 static char buf[BUFSIZE]; 48 49 ssize_t 50 pread(fd, dest, size) 51 int fd; 52 void *dest; 53 size_t size; 54 { 55 int rsize; 56 57 rsize = size; 58 while (rsize > 0) { 59 int count, got; 60 61 count = (rsize < BUFSIZE ? rsize : BUFSIZE); 62 63 got = read(fd, buf, count); 64 if (got < 0) 65 return (-1); 66 67 /* put to physical space */ 68 vpbcopy(buf, dest, got); 69 70 dest += got; 71 rsize -= got; 72 if (got < count) 73 break; /* EOF */ 74 } 75 return (size - rsize); 76 } 77