lib/diskpart.c

/* 
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) Hewlett-Packard (Paul Bame) paul_bame@hp.com
 */
#include "common.h"
#include <stdio.h>

int
is_extended(int id)
{
    switch(id)
    {
    case DOS_EXTENDED_PARTITION:
    case LINUX_EXTENDED_PARTITION:
    case WIN98_EXTENDED_PARTITION:
	return 1;
    }
    return 0;
}

int
load_partitions(int bootdev, struct diskpartition *mptab, int maxparts)
{
    struct firstblock fb;
    struct partition *ptab = &fb.part[0];
    int i;
    int ex = -1;
    int extnum = 4;
    unsigned offset;
	
    /* seekread MBR */
    if (seekread(bootdev, (char *)&fb, sizeof fb, 0) == -1)
	return 0;

    if (fb.dosmagic[0] != 0x55 || fb.dosmagic[1] != 0xaa)
	return 0;

    for (i = 0; i < 4; i++)
    {
	mptab[i].start = __le32_to_cpu(ptab[i].start_sect);
	mptab[i].length = __le32_to_cpu(ptab[i].nr_sects);
	mptab[i].id = ptab[i].sys_ind;
	if (is_extended(ptab[i].sys_ind))
	    ex = i;
    }

    if (ex != -1)
    {
	offset = mptab[ex].start;
	while (extnum < maxparts)
	{
	    if (disk_2gb_limit && offset >= (2 * (GB / 512))) { /* weird () to quiet compiler */
		printf("NOTE: Extended partition %d might be beyond reach of IPL\r\n",
				extnum + 1);
	    }

	    fb.dosmagic[0] = 0; // wipe dosmagic flag just to be on the safe side
	    if (seekread(bootdev, (char *)&fb, sizeof fb, 512ULL * offset) == -1) {
		printf("seekread(bootdev,..., 512 * 0x%x) failed!\n\r", offset);
		break;
	    }
	    if (fb.dosmagic[0] != 0x55 || fb.dosmagic[1] != 0xaa)
	    {
		// Seems to not be an extended partition, so exit.
		break;
	    }

	    mptab[extnum].start = __le32_to_cpu(ptab[0].start_sect) + offset;
	    mptab[extnum].length = __le32_to_cpu(ptab[0].nr_sects);
	    mptab[extnum].id = ptab[0].sys_ind;

	    offset = mptab[extnum].start + __le32_to_cpu(ptab[1].start_sect);

	    extnum++;
	    if (!is_extended(ptab[1].sys_ind))
		break;
	}
    }

    return 1;
}

void
print_ptab_pretty(struct diskpartition *mptab, int maxparts)
{
    int i;
    const int mbshift = 20 - 9;

    printf("Partition Start(MB) End(MB) Id Type\n\r");
    for (i = 0; i < maxparts; i++)
    {
	if (mptab[i].id != 0 && ! is_extended(mptab[i].id))
	    printf("%-9x %8d %7d %3x %s\n\r",
		i + 1,
		1 + (mptab[i].start >> mbshift),
		(mptab[i].start + mptab[i].length) >> mbshift,
		mptab[i].id,
		mptab[i].id == LINUX_EXT2_PARTITION ? "ext2" :
			(mptab[i].id == LINUX_SWAP_PARTITION ? "swap" :
				(mptab[i].id == LINUX_RAID_PARTITION ? "RAID" : 
					(mptab[i].id == PALO_PARTITION ? "Palo" : "Unknown"))));
    }
}