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/*
* This file and its contents are supplied under the terms of the
* Common Development and Distribution License ("CDDL"), version 1.0.
* You may only use this file in accordance with the terms of version
* 1.0 of the CDDL.
*
* A full copy of the text of the CDDL should have accompanied this
* source. A copy of the CDDL is also available via the Internet at
* http://www.illumos.org/license/CDDL.
*/
/*
* Copyright 2015 Toomas Soome <tsoome@me.com>
*/
/*
* Chain loader to load BIOS boot block either from MBR or PBR.
*
* Note the boot block location 0000:7c000 conflicts with loader, so we need to
* read in to temporary space and relocate on exec, when btx is stopped.
*/
#include <sys/cdefs.h>
#include <stand.h>
#include <sys/param.h>
#include <sys/linker.h>
#include <sys/diskmbr.h>
#include "bootstrap.h"
#include "libi386/vbe.h"
#include "libi386/libi386.h"
#include "btxv86.h"
/*
* The MBR/VBR is located in first sector of disk/partition.
* Read 512B to temporary location and set up relocation. Then
* exec relocator.
*/
#define SECTOR_SIZE (512)
COMMAND_SET(chain, "chain", "chain load boot block from device", command_chain);
static int
command_chain(int argc, char *argv[])
{
int fd, len, size = SECTOR_SIZE;
struct stat st;
vm_offset_t mem = 0x100000;
struct i386_devdesc *rootdev;
if (argc == 1) {
command_errmsg = "no device or file name specified";
return (CMD_ERROR);
}
if (argc != 2) {
command_errmsg = "invalid trailing arguments";
return (CMD_ERROR);
}
fd = open(argv[1], O_RDONLY);
if (fd == -1) {
command_errmsg = "open failed";
return (CMD_ERROR);
}
len = strlen(argv[1]);
if (argv[1][len-1] != ':') {
if (fstat(fd, &st) == -1) {
command_errmsg = "stat failed";
close(fd);
return (CMD_ERROR);
}
size = st.st_size;
} else if (strncmp(argv[1], "disk", 4) != 0) {
command_errmsg = "can only use disk device";
close(fd);
return (CMD_ERROR);
}
i386_getdev((void **)(&rootdev), argv[1], NULL);
if (rootdev == NULL) {
command_errmsg = "can't determine root device";
close(fd);
return (CMD_ERROR);
}
if (archsw.arch_readin(fd, mem, size) != size) {
command_errmsg = "failed to read disk";
close(fd);
return (CMD_ERROR);
}
close(fd);
if (argv[1][len-1] == ':' &&
*((uint16_t *)PTOV(mem + DOSMAGICOFFSET)) != DOSMAGIC) {
command_errmsg = "wrong magic";
return (CMD_ERROR);
}
bios_set_text_mode(3);
relocater_data[0].src = mem;
relocater_data[0].dest = 0x7C00;
relocater_data[0].size = size;
relocator_edx = bd_unit2bios(rootdev);
relocator_esi = relocater_size;
relocator_ds = 0;
relocator_es = 0;
relocator_fs = 0;
relocator_gs = 0;
relocator_ss = 0;
relocator_cs = 0;
relocator_sp = 0x7C00;
relocator_ip = 0x7C00;
relocator_a20_enabled = 0;
i386_copyin(relocater, 0x600, relocater_size);
dev_cleanup();
__exec((void *)0x600);
panic("exec returned");
return (CMD_ERROR); /* not reached */
}
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