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Recognize the "fixed" geometry in boot1 so that DD disks are not

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interpreted as real fdisk tables (and fail).
This commit is contained in:
Peter Wemm 2001-11-21 08:31:45 +00:00
parent 2548a00710
commit fef8392d99
1 changed files with 30 additions and 5 deletions
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35
sys/kern/subr_diskmbr.c
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@ -59,12 +59,29 @@
static volatile u_char dsi_debug;
/*
* This is what we have embedded in every boot1 for supporting the bogus
* "Dangerously Dedicated" mode. However, the old table is broken because
* it has an illegal geometry in it - it specifies 256 heads (heads = end
* head + 1) which causes nasty stuff when that wraps to zero in bios code.
* eg: divide by zero etc. This caused the dead-thinkpad problem, numerous
* SCSI bios crashes, EFI to crash, etc.
*
* We still have to recognize the old table though, even though we stopped
* inflicting it apon the world.
*/
static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
};
static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
{ 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
};
static int check_part __P((char *sname, struct dos_partition *dp,
u_long offset, int nsectors, int ntracks,
@ -109,7 +126,8 @@ check_part(sname, dp, offset, nsectors, ntracks, mbr_offset )
* If ssector1 is on a cylinder >= 1024, then ssector can't be right.
* Allow the C/H/S for it to be 1023/ntracks-1/nsectors, or correct
* apart from the cylinder being reduced modulo 1024. Always allow
* 1023/255/63.
* 1023/255/63, because this is the official way to represent
* pure-LBA for the starting position.
*/
if ((ssector < ssector1
&& ((chs_ssect == nsectors && dp->dp_shd == ntracks - 1
@ -129,7 +147,12 @@ check_part(sname, dp, offset, nsectors, ntracks, mbr_offset )
+ mbr_offset;
esector1 = ssector1 + dp->dp_size - 1;
/* Allow certain bogus C/H/S values for esector, as above. */
/*
* Allow certain bogus C/H/S values for esector, as above. However,
* heads == 255 isn't really legal and causes some BIOS crashes. The
* correct value to indicate a pure-LBA end is 1023/heads-1/sectors -
* usually 1023/254/63. "heads" is base 0, "sectors" is base 1.
*/
if ((esector < esector1
&& ((chs_esect == nsectors && dp->dp_ehd == ntracks - 1
&& chs_ecyl == 1023)
@ -228,9 +251,11 @@ reread_mbr:
}
if (bcmp(dp0, historical_bogus_partition_table,
sizeof historical_bogus_partition_table) == 0) {
TRACE(("%s: invalid primary partition table: historical\n",
sname));
sizeof historical_bogus_partition_table) == 0 ||
bcmp(dp0, historical_bogus_partition_table_fixed,
sizeof historical_bogus_partition_table_fixed) == 0) {
printf(
"%s: invalid primary partition table: Dangerously Dedicated (ignored)\n", sname);
error = EINVAL;
goto done;
}