package partition_table::dos; use diagnostics; use strict; use vars qw(@ISA); @ISA = qw(partition_table::raw); use Time::HiRes qw(usleep); use common; use partition_table::raw; use partition_table; use fs::proc_partitions; use fs::type; use c; =head1 SYNOPSYS Read/write MBR partition tables =head1 Functions =over =cut my @fields = qw(active start_head start_sec start_cyl pt_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 use_pt_type { 1 } 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 docs/Partition-ends-after-end-of-disk.txt for more $hd->{geom}{sectors} * $hd->{geom}{heads} * $hd->{geom}{cylinders}; } my $two_TB = 2 * 1024 * 1024 * 2048; sub max_partition_start { $two_TB - 1 } sub max_partition_size { $two_TB - 1 } sub get_rawCHS { my ($part) = @_; exists $part->{start_cyl} or internal_error("get_rawCHS $part->{device}"); [ $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} || $part->{pt_type} or return; my ($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} || $part->{pt_type} or return; sector2CHS($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) | (($c >> 2) & 0xc0) ]; } =item sector2CHS($geom, $start) returns (cylinder, head, sector) =cut sub sector2CHS { my ($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 $chs_start_v2 or log::l("is_geometry_valid_for_the_partition_table failed for ($_->{device}, $_->{start}): $chs_start_v1 vs $chs_start_v2 with geometry " . geometry_to_string($geom)); $chs_end_v1 eq $chs_end_v2 or log::l("is_geometry_valid_for_the_partition_table failed for ($_->{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, 240, 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->{sectors}, @valid_nb_sectors) or return { invalid => 1 }; $geom; } sub geometry_from_edd { my ($hd, $edd_dir) = @_; my $sectors = cat_("$edd_dir/legacy_sectors_per_track") or return; my $heads = cat_("$edd_dir/legacy_max_head") or return; my $geom = { sectors => 0 + $sectors, heads => 1 + $heads, from_edd => 1 }; is_geometry_valid_for_the_partition_table($hd, $geom, 0) or return; partition_table::raw::compute_nb_cylinders($geom, $hd->{totalsectors}); log::l("geometry_from_edd $hd->{device} $hd->{volume_id}: " . geometry_to_string($geom)); $geom; } sub try_every_geometry { my ($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") if !$hd->{geom}{from_edd}; return; } my $default_ok = is_geometry_valid_for_the_partition_table($hd, $hd->{geom}, 0); if ($guessed_geom->{invalid}) { log::l("$hd->{device}: no valid geometry guessed from partition table"); $default_ok and return; $guessed_geom = try_every_geometry($hd) or return; } if ($guessed_geom->{heads} == $hd->{geom}{heads} && $guessed_geom->{sectors} == $hd->{geom}{sectors}) { # cool! } else { 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_one { 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{pt_type} = 'BIOS_GRUB' if $h{pt_type} == 0 && $h{size} > 0; fs::type::set_pt_type(\%h, $h{pt_type}); \%h; } (1..$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 $hd->{device}"; if ($hd->{current_pt_table_type} ne "dos") { # libparted may have ignored it because of overlapping partitions or other error # while it is actually a partition table. $hd->{fs_type_from_magic} and die "unpartitionned disk"; my $primary = partition_table::raw::pt_info_to_primary($hd, [ @pt ]); foreach my $i (@{$primary->{normal}}) { if ($i->{active} && $i->{active} != 0x80 || $hd->{totalsectors} && $i->{start} > $hd->{totalsectors}) { die "Invalid DOS partition table"; } } } [ @pt ]; } =item start_write($hd) Prepare to write the partition table (and extended ones) =cut sub start_write { my ($hd) = @_; log::l("partition::dos::write $hd->{device}"); #- 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 $hd->{device} for writing"; if ($hd->{was_hybrid_iso}) { log::l("partition::dos::start_write erasing hybrid iso9660 signature"); c::lseek_sector(fileno($F), 0, 0x8001) or return 0; syswrite $F, "\0\0\0\0\0", 5 or return 0; $hd->{was_hybrid_iso} = 0; } } $F; } =item start_write($hd, $F, $sector, $pt) Write the partition table (and extended ones). For each entry, it uses fields: start, size, pt_type, active =cut sub write { my ($hd, $F, $sector, $pt) = @_; if (!$::testing) { 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; $_->{pt_type} ||= 0; $_->{size} ||= 0; #- for no warning syswrite $F, pack($format, @$_{@fields}), psizeof($format) or return 0; } syswrite $F, $magic, length $magic or return 0; 1; } sub end_write { my ($hd, $F) = @_; close $F; } sub need_to_tell_kernel { my ($hd) = @_; # Whenever udevd receives a change event for a raw disk device it is watching, it asks the kernel to # rescan the partition table on that device by calling the BLKRRPART ioctl. This is only successful # if none of the partitions on that device are currently mounted. So if any partitions are mounted, # we need to tell the kernel what has changed ourselves. # The udev/rules.d/60-block.rules file causes the raw disk devices to be watched by udev. This file is # not present in the cut-down system used to run the classic installer, so we always need to tell the # kernel in that case. # diskdrake will not let the user delete an individual partition that is mounted, but will let the # user clear all partitions. So initialize() records if any partitions were mounted and we take note # of that here. return 1 if ! -e '/usr/lib/udev/rules.d/60-block.rules' || delete $hd->{hadMountedPartitions} || any { $_->{isMounted} } partition_table::get_normal_parts($hd); # No further actions must be performed until the kernel has been informed of the changes. There is # no easy way to check that udevd has received the uevent and called the BLKRRPART ioctl, so do it # the hard way. my $tries = 0; do { usleep(100000); log::l("checking that udevd has informed the kernel of partition table changes"); eval { fs::proc_partitions::compare($hd) }; return 0 if !$@; $tries++; } while $tries < 5; # We don't expect to get here, but fail safe if so. log::l("udevd failed to inform kernel of partition table changes"); $hd->{rebootNeeded} = 1; 1; } sub empty_raw { { raw => [ ({}) x $nb_primary ] } } sub initialize { my ($class, $hd) = @_; # Remember whether any existing partitions are mounted, for use by need_to_tell_kernel(). $hd->{hadMountedPartitions} = 1 if any { $_->{isMounted} } partition_table::get_normal_parts($hd); # Remember whether this was a hybrid ISO so we can wipe the iso9660 signature. $hd->{was_hybrid_iso} = 1 if $hd->{primary}{is_hybrid_iso}; $hd->{primary} = empty_raw(); bless $hd, $class; } 1;