HardenedBSD/lib/libdisk/write_i386_disk.c

/*
 * ----------------------------------------------------------------------------
 * "THE BEER-WARE LICENSE" (Revision 42):
 * <phk@FreeBSD.org> wrote this file.  As long as you retain this notice you
 * can do whatever you want with this stuff. If we meet some day, and you think
 * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
 * ----------------------------------------------------------------------------
 */

#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/disklabel.h>
#include <sys/diskmbr.h>
#include <paths.h>
#include "libdisk.h"

/*
 * XXX: A lot of hardcoded 512s probably should be foo->sector_size;
 *	I'm not sure which, so I leave it like it worked before. --schweikh
 */
static int
Write_FreeBSD(int fd, const struct disk *new, const struct chunk *c1)
{
	struct disklabel *dl;
	int i;
	void *p;
	u_char buf[BBSIZE];

	for (i = 0; i < BBSIZE/512; i++) {
		if (!(p = read_block(fd, i + c1->offset, 512)))
			return (1);
		memcpy(buf + 512 * i, p, 512);
		free(p);
	}
	if (new->boot1)
		memcpy(buf, new->boot1, 512);

	if (new->boot2)
		memcpy(buf + 512, new->boot2, BBSIZE - 512);

	dl = (struct disklabel *)(buf + 512 * LABELSECTOR + LABELOFFSET);
	Fill_Disklabel(dl, new, c1);

	for (i = 0; i < BBSIZE / 512; i++)
		write_block(fd, i + c1->offset, buf + 512 * i, 512);

	return 0;
}

static void
Write_Int32(u_int32_t *p, u_int32_t v)
{
	u_int8_t *bp = (u_int8_t *)p;

	bp[0] = (v >> 0) & 0xff;
	bp[1] = (v >> 8) & 0xff;
	bp[2] = (v >> 16) & 0xff;
	bp[3] = (v >> 24) & 0xff;
}

/*
 * Special install-time configuration for the i386 boot0 boot manager.
 */
static void
Cfg_Boot_Mgr(u_char *mbrblk, int edd)
{

	if (mbrblk[0x1b0] == 0x66 && mbrblk[0x1b1] == 0xbb) {
		if (edd)
			mbrblk[0x1bb] |= 0x80;	/* Packet mode on */
		else
			mbrblk[0x1bb] &= 0x7f;	/* Packet mode off */
	}
}

int
Write_Disk(const struct disk *d1)
{
	int fd, j;
	uint i;
	struct chunk *c1;
	int ret = 0;
	char device[64];
	u_char *mbrblk;
	struct dos_partition *dp,work[NDOSPART];
	int s[4];
	int need_edd = 0;	/* Need EDD (packet interface) */

	strcpy(device, _PATH_DEV);
        strcat(device, d1->name);

        fd = open(device, O_RDWR);
        if (fd < 0)
                return 1;

	memset(s, 0, sizeof s);
	if (!(mbrblk = read_block(fd, 0, d1->sector_size))) {
		close (fd);
		return (1);
	}
	dp = (struct dos_partition *)(mbrblk + DOSPARTOFF);
	memcpy(work, dp, sizeof work);
	dp = work;
	free(mbrblk);
	for (c1 = d1->chunks->part; c1; c1 = c1->next) {
		if (c1->type == unused)
			continue;
		if (!strcmp(c1->name, "X"))
			continue;
		j = c1->name[strlen(d1->name) + 1] - '1';
		if (j < 0 || j > 3)
			continue;
		s[j]++;
		if (c1->type == freebsd)
			ret += Write_FreeBSD(fd, d1, c1);

		Write_Int32(&dp[j].dp_start, c1->offset);
		Write_Int32(&dp[j].dp_size, c1->size);

		i = c1->offset;
		if (i >= 1024 * d1->bios_sect * d1->bios_hd) {
			dp[j].dp_ssect = 0xff;
			dp[j].dp_shd = 0xff;
			dp[j].dp_scyl = 0xff;
			need_edd++;
		} else {
			dp[j].dp_ssect = i % d1->bios_sect;
			i -= dp[j].dp_ssect++;
			i /= d1->bios_sect;
			dp[j].dp_shd =  i % d1->bios_hd;
			i -= dp[j].dp_shd;
			i /= d1->bios_hd;
			dp[j].dp_scyl = i;
			i -= dp[j].dp_scyl;
			dp[j].dp_ssect |= i >> 2;
		}
#ifdef DEBUG
		printf("S:%lu = (%x/%x/%x)", c1->offset,
		       dp[j].dp_scyl, dp[j].dp_shd, dp[j].dp_ssect);
#endif

		i = c1->end;
		dp[j].dp_esect = i % d1->bios_sect;
		i -= dp[j].dp_esect++;
		i /= d1->bios_sect;
		dp[j].dp_ehd =  i % d1->bios_hd;
		i -= dp[j].dp_ehd;
		i /= d1->bios_hd;
		if (i > 1023)
			i = 1023;
		dp[j].dp_ecyl = i;
		i -= dp[j].dp_ecyl;
		dp[j].dp_esect |= i >> 2;
#ifdef DEBUG
		printf("  E:%lu = (%x/%x/%x)\n", c1->end,
		       dp[j].dp_ecyl, dp[j].dp_ehd, dp[j].dp_esect);
#endif

		dp[j].dp_typ = c1->subtype;
		if (c1->flags & CHUNK_ACTIVE)
			dp[j].dp_flag = 0x80;
		else
			dp[j].dp_flag = 0;
	}
	j = 0;
	for (i = 0; i < NDOSPART; i++) {
		if (!s[i])
			memset(dp + i, 0, sizeof *dp);
		if (dp[i].dp_flag)
			j++;
	}
	if (!j)
		for(i = 0; i < NDOSPART; i++)
			if (dp[i].dp_typ == 0xa5)
				dp[i].dp_flag = 0x80;

	if (!(mbrblk = read_block(fd, 0, d1->sector_size))) {
		close (fd);
		return (1);
	}
	if (d1->bootmgr) {
		memcpy(mbrblk, d1->bootmgr, DOSPARTOFF);
		Cfg_Boot_Mgr(mbrblk, need_edd);
        }
	memcpy(mbrblk + DOSPARTOFF, dp, sizeof *dp * NDOSPART);
	mbrblk[512-2] = 0x55;
	mbrblk[512-1] = 0xaa;
	write_block(fd, 0, mbrblk, d1->sector_size);
	if (d1->bootmgr && d1->bootmgr_size > d1->sector_size)
		for (i = 1; i * d1->sector_size <= d1->bootmgr_size; i++)
			write_block(fd, i, &d1->bootmgr[i * d1->sector_size],
				    d1->sector_size);

	close(fd);
	return 0;
}