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package partition_table_gpt; # $Id$
use diagnostics;
use strict;
use vars qw(@ISA);
@ISA = qw(partition_table_raw);
use common;
use partition_table_raw;
use partition_table_dos;
use partition_table;
use c;
my %gpt_types = (
0x00 => "\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00",
0x82 => "\x6d\xfd\x57\x06\xab\xa4\xc4\x43\x84\xe5\x09\x33\xc8\x4b\x4f\x4f",
0x83 => "\xA2\xA0\xD0\xEB\xE5\xB9\x33\x44\x87\xC0\x68\xB6\xB7\x26\x99\xC7",
0x8e => "\x79\xd3\xd6\xe6\x07\xf5\xc2\x44\xa2\x3c\x23\x8f\x2a\x3d\xf9\x28",
0xfd => "\x0f\x88\x9d\xa1\xfc\x05\x3b\x4d\xa0\x06\x74\x3f\x0f\x84\x91\x1e",
0xef => "\x28\x73\x2A\xC1\x1F\xF8\xd2\x11\xBA\x4B\x00\xA0\xC9\x3E\xC9\x3B",
# legacy_partition_table => "\x41\xEE\x4D\x02\xE7\x33\xd3\x11\x9D\x69\x00\x08\xC7\x81\xF3\x9F"
# PARTITION_MSFT_RESERVED_GUID "\x16\xE3\xC9\xE3\x5C\x0B\xB8\x4D\x81\x7D\xF9\x2D\xF0\x02\x15\xAE"
#PARTITION_RESERVED_GUID "\x39\x33\xa6\x8d\x07\x00\xc0\x60\xc4\x36\x08\x3a\xc8\x23\x09\x08"
);
my $current_revision = 0x00010200;
my ($main_format, $main_fields) = list2kv(
a8 => 'magic',
V => 'revision',
V => 'headerSize',
V => 'headerCRC32',
a4 => 'blank1',
Q => 'myLBA',
Q => 'alternateLBA',
Q => 'firstUsableLBA',
Q => 'lastUsableLBA',
a16 => 'guid',
Q => 'partitionEntriesLBA',
V => 'nbPartitions',
V => 'partitionEntrySize',
V => 'partitionEntriesCRC32',
);
my ($partitionEntry_format, $partitionEntry_fields) = list2kv(
a16 => 'gpt_type',
a16 => 'guid',
Q => 'start',
Q => 'ending',
a8 => 'efi_attributes',
a72 => 'name',
);
$_ = join('', @$_) foreach $main_format, $partitionEntry_format;
my $magic = "EFI PART";
sub crc32 {
my ($buffer) = @_;
my $crc = 0xFFFFFFFF;
foreach (unpack "C*", $buffer) {
my $subcrc = ($crc ^ $_) & 0xFF;
for (my $j = 8; $j > 0; $j--){
my $b = $subcrc & 1;
$subcrc = ($subcrc >> 1) & 0x7FFFFFFF;
$subcrc = $subcrc ^ 0xEDB88320 if $b;
}
$crc = ($crc >> 8) ^ $subcrc;
}
$crc ^ 0xFFFFFFFF;
}
sub compute_headerCRC32 {
my ($info) = @_;
local $info->{headerCRC32} = 0;
crc32(pack($main_format, @$info{@$main_fields}));
}
sub read_header {
my ($sector, $F) = @_;
my $tmp;
c::lseek_sector(fileno($F), $sector, 0) or die "reading of partition in sector $sector failed";
sysread $F, $tmp, psizeof($main_format) or die "error while reading partition table in sector $sector";
my %info; @info{@$main_fields} = unpack $main_format, $tmp;
$info{magic} eq $magic or die "bad magic number";
$info{myLBA} == $sector or die "myLBA is not the same";
$info{headerSize} == psizeof($main_format) or die "bad partition table header size";
$info{partitionEntrySize} == psizeof($partitionEntry_format) or die "bad partitionEntrySize";
$info{revision} <= $current_revision or log::l("oops, this is a new GPT revision ($info{revision} > $current_revision)");
$info{headerCRC32} == compute_headerCRC32(\%info) or die "bad partition table checksum";
\%info
}
sub read_partitionEntries {
my ($info, $F) = @_;
my $tmp;
c::lseek_sector(fileno($F), $info->{partitionEntriesLBA}, 0) or die "can't seek to sector partitionEntriesLBA";
sysread $F, $tmp, psizeof($partitionEntry_format) * $info->{nbPartitions} or die "error while reading partition table in sector $info->{partitionEntriesLBA}";
$info->{partitionEntriesCRC32} == crc32($tmp) or die "bad partition entries checksum";
c::lseek_sector(fileno($F), $info->{partitionEntriesLBA}, 0) or die "can't seek to sector partitionEntriesLBA";
my %gpt_types_rev = reverse %gpt_types;
my @pt =
map {
sysread $F, $tmp, psizeof($partitionEntry_format) or die "error while reading partition table in sector $info->{partitionEntriesLBA}";
my %h; @h{@$partitionEntry_fields} = unpack $partitionEntry_format, $tmp;
$h{size} = $h{ending} - $h{start};
$h{type} = $gpt_types_rev{$h{gpt_type}};
$h{type} = 0x100 if !defined $h{type};
\%h;
} (1 .. $info->{nbPartitions});
\@pt;
}
sub read {
my ($hd, $sector) = @_;
my $tmp;
my $l = partition_table_dos::read($hd, $sector);
my @l = grep { $_->{size} && $_->{type} && !partition_table::isExtended($_) } @$l;
@l == 1 or die "bad PMBR";
$l[0]{type} == 0xee or die "bad PMBR";
my $myLBA = $l[0]{start};
local *F; partition_table_raw::openit($hd, *F) or die "failed to open device";
my $info1 = eval { read_header($myLBA, *F) };
my $info2 = eval { read_header($info1->{alternateLBA} || $l[0]{start} + $l[0]{size} - 1, *F) }; #- what about using $hd->{totalsectors} ???
my $info = $info1 || { %$info2, myLBA => $info2->{alternateLBA}, alternateLBA => $info2->{myLBA}, partitionEntriesLBA => $info2->{alternateLBA} + 1 } or die;
my $pt = $info1 && $info2 ?
eval { $info1 && read_partitionEntries($info1, *F) } || read_partitionEntries($info2, *F) :
read_partitionEntries($info, *F);
$hd->raw_removed($pt);
$pt, $info;
}
# write the partition table (and extended ones)
# for each entry, it uses fields: start, size, type, active
sub write {
my ($hd, $sector, $pt, $info) = @_;
foreach (@$pt) {
$_->{ending} = $_->{start} + $_->{size};
$_->{gpt_type} = $gpt_types{$_->{type}} || $_->{gpt_type} || $gpt_types{0x83};
}
my $partitionEntries = join('', map {
pack($partitionEntry_format, @$_{@$partitionEntry_fields})
} (@$pt, ({}) x ($info->{nbPartitions} - @$pt)));
$info->{partitionEntriesCRC32} = crc32($partitionEntries);
$info->{headerCRC32} = compute_headerCRC32($info);
my $info2 = { %$info,
myLBA => $info->{alternateLBA}, alternateLBA => $info->{myLBA},
partitionEntriesLBA => $info->{alternateLBA} - psizeof($partitionEntry_format) * $info->{nbPartitions} / 512,
};
$info2->{headerCRC32} = compute_headerCRC32($info2);
{
# write the PMBR
my $pmbr = partition_table_dos::clear_raw();
$pmbr->{raw}[0] = { type => 0xee, local_start => $info->{myLBA}, size => $info->{alternateLBA} - $info->{myLBA} + 1 };
partition_table_dos::write($hd, $sector, $pmbr->{raw});
}
local *F;
partition_table_raw::openit($hd, *F, 2) or die "error opening device $hd->{device} for writing";
c::lseek_sector(fileno(F), $info->{myLBA}, 0) or return 0;
#- pad with 0's
syswrite F, pack($main_format, @$info{@$main_fields}) . "\0" x 512, 512 or return 0;
c::lseek_sector(fileno(F), $info->{alternateLBA}, 0) or return 0;
#- pad with 0's
syswrite F, pack($main_format, @$info2{@$main_fields}) . "\0" x 512, 512 or return 0;
c::lseek_sector(fileno(F), $info->{partitionEntriesLBA}, 0) or return 0;
syswrite F, $partitionEntries or return 0;
c::lseek_sector(fileno(F), $info2->{partitionEntriesLBA}, 0) or return 0;
syswrite F, $partitionEntries or return 0;
common::sync();
1;
}
sub raw_removed {
my ($hd, $raw) = @_;
@$raw = grep { $_->{size} && $_->{type} } @$raw;
}
sub can_raw_add {
my ($hd) = @_;
@{$hd->{primary}{raw}} < $hd->{primary}{info}{nbPartitions};
}
sub raw_add {
my ($hd, $raw, $part) = @_;
$hd->can_raw_add or die "raw_add: partition table already full";
push @$raw, $part;
}
sub info {
my ($hd) = @_;
my $nb_sect = 32;
#- build a default suitable partition table,
#- checksum will be built when writing on disk.
{
magic => $magic,
revision => $current_revision,
headerSize => psizeof($main_format),
myLBA => 1,
alternateLBA => $hd->{totalsectors} - 1,
firstUsableLBA => $nb_sect + 2,
lastUsableLBA => $hd->{totalsectors} - $nb_sect - 2,
guid => 'TODO',
partitionEntriesLBA => 2,
nbPartitions => $nb_sect * 512 / psizeof($partitionEntry_format),
partitionEntrySize => psizeof($partitionEntry_format),
};
}
sub clear_raw {
my ($hd) = @_;
{ raw => [], info => info($hd) };
}
1;
|
