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package partition_table::dos; # $Id$
use diagnostics;
use strict;
use vars qw(@ISA);
@ISA = qw(partition_table::raw);
use common;
use partition_table::raw;
use partition_table;
use c;
my @fields = qw(active start_head start_sec start_cyl type end_head end_sec end_cyl start size);
my $format = "C8 V2";
my $magic = "\x55\xAA";
my $nb_primary = 4;
my $offset = $common::SECTORSIZE - length($magic) - $nb_primary * common::psizeof($format);
sub hasExtended { 1 }
sub geometry_to_string {
my ($geom) = @_;
"$geom->{cylinders}/$geom->{heads}/$geom->{sectors}";
}
sub last_usable_sector {
my ($hd) = @_;
#- do not use totalsectors, see gi/docs/Partition-ends-after-end-of-disk.txt for more
$hd->{geom}{sectors} * $hd->{geom}{heads} * $hd->{geom}{cylinders};
}
sub get_rawCHS {
my ($part) = @_;
[ $part->{start_cyl}, $part->{start_head}, $part->{start_sec} ],
[ $part->{end_cyl}, $part->{end_head}, $part->{end_sec} ];
}
sub set_rawCHS {
my ($part, $raw_chs_start, $raw_chs_end) = @_;
($part->{start_cyl}, $part->{start_head}, $part->{start_sec}) = @$raw_chs_start;
($part->{end_cyl}, $part->{end_head}, $part->{end_sec}) = @$raw_chs_end;
}
sub compute_CHS {
my ($hd, $part) = @_;
my ($chs_start, $chs_end) = CHS_from_part_linear($hd->{geom}, $part);
set_rawCHS($part, $chs_start ? CHS2rawCHS($hd->{geom}, $chs_start) : [0,0,0],
$chs_end ? CHS2rawCHS($hd->{geom}, $chs_end) : [0,0,0]);
}
sub CHS_from_part_rawCHS {
my ($part) = @_;
$part->{start} || $part->{type} or return;
my ($raw_chs_start, $raw_chs_end) = get_rawCHS($part);
rawCHS2CHS($raw_chs_start), rawCHS2CHS($raw_chs_end);
}
sub CHS_from_part_linear {
my ($geom, $part) = @_;
$part->{start} || $part->{type} or return;
sector2CHS($geom, $part->{start}), sector2CHS($geom, $part->{start} + $part->{size} - 1);
}
sub rawCHS2CHS {
my ($chs) = @_;
my ($c, $h, $s) = @$chs;
[ $c | (($s & 0xc0) << 2), $h, ($s & 0x3f) - 1 ];
}
sub CHS2rawCHS {
my ($geom, $chs) = @_;
my ($c, $h, $s) = @$chs;
if ($c > 1023) {
#- no way to have a #cylinder >= 1024
$c = 1023;
$h = $geom->{heads} - 1;
$s = $geom->{sectors} - 1;
}
[ $c & 0xff, $h, ($s + 1) | (($c >> 2) & 0xc0) ];
}
# returns (cylinder, head, sector)
sub sector2CHS {
my ($geom, $start) = @_;
my ($s, $h);
($start, $s) = divide($start, $geom->{sectors});
($start, $h) = divide($start, $geom->{heads});
[ $start, $h, $s ];
}
sub is_geometry_valid_for_the_partition_table {
my ($hd, $geom, $no_log) = @_;
every {
my ($chs_start_v1, $chs_end_v1) = map { join(',', @$_) } CHS_from_part_rawCHS($_) or next;
my ($chs_start_v2, $chs_end_v2) = map { join(',', @$_) } map { [ min($_->[0], 1023), $_->[1], $_->[2] ] } CHS_from_part_linear($geom, $_);
if (!$no_log) {
$chs_start_v1 eq $chs_start_v2 or log::l("check_geometry_using_the_partition_table failed for ($_->{device}, $_->{start}): $chs_start_v1 vs $chs_start_v2 with geometry " . geometry_to_string($geom));
$chs_end_v1 eq $chs_end_v2 or log::l("check_geometry_using_the_partition_table failed for ($_->{device}, " . ($_->{start} + $_->{size} - 1) . "): $chs_end_v1 vs $chs_end_v2 with geometry " . geometry_to_string($geom));
}
$chs_start_v1 eq $chs_start_v2 && $chs_end_v1 eq $chs_end_v2;
} @{$hd->{primary}{normal} || []};
}
#- from parted, thanks!
my @valid_nb_sectors = (63, 61, 48, 32, 16);
my @valid_nb_heads = (255, 192, 128, 96, 64, 61, 32, 17, 16);
sub guess_geometry_from_partition_table {
my ($hd) = @_;
my @chss = map { CHS_from_part_rawCHS($_) } @{$hd->{primary}{normal} || []} or return { empty => 1 };
my ($nb_heads, $nb_sectors) = (max(map { $_->[1] } @chss) + 1, max(map { $_->[2] } @chss) + 1);
my $geom = { sectors => $nb_sectors, heads => $nb_heads };
partition_table::raw::compute_nb_cylinders($geom, $hd->{totalsectors});
log::l("guess_geometry_from_partition_table $hd->{device}: " . geometry_to_string($geom));
member($geom->{heads}, @valid_nb_heads) && member($geom->{sectors}, @valid_nb_sectors) or return { invalid => 1 };
$geom;
}
sub try_every_geometry {
my ($hd) = @_;
my $geom = {};
foreach (@valid_nb_sectors) {
$geom->{sectors} = $_;
foreach (@valid_nb_heads) {
$geom->{heads} = $_;
if (is_geometry_valid_for_the_partition_table($hd, $geom, 1)) {
partition_table::raw::compute_nb_cylinders($geom, $hd->{totalsectors});
log::l("try_every_geometry $hd->{device}: found " . geometry_to_string($geom));
return $geom;
}
}
}
log::l("$hd->{device}: argh! no geometry exists for this partition table");
undef;
}
sub set_best_geometry_for_the_partition_table {
my ($hd) = @_;
my $guessed_geom = guess_geometry_from_partition_table($hd);
if ($guessed_geom->{empty}) {
log::l("$hd->{device}: would need looking at BIOS info to find out geometry");
return;
}
if ($guessed_geom->{invalid}) {
log::l("$hd->{device}: no valid geometry guessed from partition table");
$guessed_geom = try_every_geometry($hd) or return;
}
if ($guessed_geom->{heads} == $hd->{geom}{heads} && $guessed_geom->{sectors} == $hd->{geom}{sectors}) {
# cool!
} else {
my $default_ok = is_geometry_valid_for_the_partition_table($hd, $hd->{geom}, 0);
my $guessed_ok = is_geometry_valid_for_the_partition_table($hd, $guessed_geom, 0);
if ($default_ok && $guessed_ok) {
#- oh my!?
log::l("$hd->{device}: both guessed and default are valid??? " . geometry_to_string($hd->{geom}) . " vs " . geometry_to_string($guessed_geom));
} elsif ($default_ok) {
log::l("$hd->{device}: keeping default geometry " . geometry_to_string($hd->{geom}));
} elsif ($guessed_ok) {
log::l("$hd->{device}: using guessed geometry " . geometry_to_string($guessed_geom) . " instead of " . geometry_to_string($hd->{geom}));
put_in_hash($hd->{geom}, $guessed_geom);
} else {
log::l("$hd->{device}: argh! no valid geometry found");
}
}
}
sub read {
my ($hd, $sector) = @_;
my $tmp;
my $F = partition_table::raw::openit($hd) or die "failed to open device";
c::lseek_sector(fileno($F), $sector, $offset) or die "reading of partition in sector $sector failed";
my @pt = map {
sysread $F, $tmp, psizeof($format) or die "error while reading partition table in sector $sector";
my %h; @h{@fields} = unpack $format, $tmp;
\%h;
} (1..$nb_primary);
#- check magic number
sysread $F, $tmp, length $magic or die "error reading magic number on disk $hd->{device}";
$tmp eq $magic or die "bad magic number on disk $hd->{device}";
[ @pt ];
}
# write the partition table (and extended ones)
# for each entry, it uses fields: start, size, type, active
sub write($$$;$) {
my ($hd, $sector, $pt) = @_;
#- handle testing for writing partition table on file only!
my $F;
if ($::testing) {
my $file = "/tmp/partition_table_$hd->{device}";
open $F, ">$file" or die "error opening test file $file";
} else {
$F = partition_table::raw::openit($hd, 2) or die "error opening device $hd->{device} for writing";
c::lseek_sector(fileno($F), $sector, $offset) or return 0;
}
@$pt == $nb_primary or die "partition table does not have $nb_primary entries";
foreach (@$pt) {
compute_CHS($hd, $_);
local $_->{start} = $_->{local_start} || 0;
$_->{active} ||= 0; $_->{type} ||= 0; $_->{size} ||= 0; #- for no warning
syswrite $F, pack($format, @$_{@fields}), psizeof($format) or return 0;
}
syswrite $F, $magic, length $magic or return 0;
1;
}
sub clear_raw { { raw => [ ({}) x $nb_primary ] } }
1;
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