sys/boot/pc32/libi386/pread.c

   1 /*
   2  * $NetBSD: pread.c,v 1.2 1997/03/22 01:48:38 thorpej Exp $
   3  */
   4
   5 /*-
   6  * Copyright (c) 1996
   7  *      Matthias Drochner.  All rights reserved.
   8  *
   9  * Redistribution and use in source and binary forms, with or without
  10  * modification, are permitted provided that the following conditions
  11  * are met:
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in the
  16  *    documentation and/or other materials provided with the distribution.
  17  * 3. All advertising materials mentioning features or use of this software
  18  *    must display the following acknowledgement:
  19  *      This product includes software developed for the NetBSD Project
  20  *      by Matthias Drochner.
  21  * 4. The name of the author may not be used to endorse or promote products
  22  *    derived from this software without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
  25  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  26  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  27  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
  28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  29  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  30  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  31  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  32  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  33  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  34  *
  35  * $FreeBSD: src/sys/boot/i386/libi386/pread.c,v 1.3 2003/08/25 23:28:31 obrien Exp $
  36  * $DragonFly: src/sys/boot/pc32/libi386/pread.c,v 1.3 2003/11/10 06:08:36 dillon Exp $
  37  */
  38
  39 /* read into destination in flat addr space */
  40
  41 #include <stand.h>
  42
  43 #include "libi386.h"
  44
  45 #ifdef SAVE_MEMORY
  46 #define BUFSIZE (1*1024)
  47 #else
  48 #define BUFSIZE (4*1024)
  49 #endif
  50
  51 static char     buf[BUFSIZE];
  52
  53 int
  54 pread(fd, dest, size)
  55         int             fd;
  56         vm_offset_t         dest;
  57         int             size;
  58 {
  59         int             rsize;
  60
  61         rsize = size;
  62         while (rsize > 0) {
  63                 int             count, got;
  64
  65                 count = (rsize < BUFSIZE ? rsize : BUFSIZE);
  66
  67                 got = read(fd, buf, count);
  68                 if (got < 0)
  69                         return (-1);
  70
  71                 /* put to physical space */
  72                 vpbcopy(buf, dest, got);
  73
  74                 dest += got;
  75                 rsize -= got;
  76                 if (got < count)
  77                         break;  /* EOF */
  78         }
  79         return (size - rsize);
  80 }