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/*
* Copyright (c) 1995-1994 The University of Utah and
* the Computer Systems Laboratory at the University of Utah (CSL).
* All rights reserved.
*
* Permission to use, copy, modify and distribute this software is hereby
* granted provided that (1) source code retains these copyright, permission,
* and disclaimer notices, and (2) redistributions including binaries
* reproduce the notices in supporting documentation, and (3) all advertising
* materials mentioning features or use of this software display the following
* acknowledgement: ``This product includes software developed by the
* Computer Systems Laboratory at the University of Utah.''
*
* THE UNIVERSITY OF UTAH AND CSL ALLOW FREE USE OF THIS SOFTWARE IN ITS "AS
* IS" CONDITION. THE UNIVERSITY OF UTAH AND CSL DISCLAIM ANY LIABILITY OF
* ANY KIND FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
*
* CSL requests users of this software to return to csl-dist@cs.utah.edu any
* improvements that they make and grant CSL redistribution rights.
*
* Author: Bryan Ford, University of Utah CSL
*/
#include <unistd.h>
#include <errno.h>
#include "dos_io.h"
#include "vm_param.h"
int dos_read(dos_fd_t fd, void *buf, vm_size_t size, vm_size_t *out_actual)
{
int err;
int actual = 0;
struct real_call_data real_call_data;
vm_offset_t dos_buf_phys = (vm_offset_t)kvtophys(dos_buf);
assert(dos_buf); assert(dos_buf_phys);
assert(dos_buf_phys < 0x100000);
dos_init_rcd(&real_call_data);
while (size > 0)
{
int little_size = size;
int little_actual;
if (little_size > DOS_BUF_SIZE)
little_size = DOS_BUF_SIZE;
real_call_data.eax = 0x3f00;
real_call_data.ebx = fd;
real_call_data.ecx = little_size;
real_call_data.ds = dos_buf_phys >> 4;
real_call_data.edx = dos_buf_phys & 15;
real_int(0x21, &real_call_data);
if (err = dos_check_err(&real_call_data))
return err;
little_actual = real_call_data.eax & 0xffff;
assert(little_actual <= little_size);
/* XXX don't copy if buf is <1MB */
memcpy(buf, dos_buf, little_actual);
buf += little_actual;
size -= little_actual;
actual += little_actual;
if (little_actual < little_size)
break;
}
*out_actual = actual;
return 0;
}
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