package partition_table_raw; use diagnostics; use strict; use common qw(:common :system :file); use devices; use c; my @fields = qw(active start_head start_sec start_cyl type end_head end_sec end_cyl start size); my $format = "C8 I2"; my $magic = "\x55\xAA"; my $nb_primary = 4; my $offset = $common::SECTORSIZE - length($magic) - $nb_primary * common::psizeof($format); my @MBR_signatures = ( [ 'empty', 0, "\0\0\0\0" ], [ 'lilo', 0x6, "LILO" ], [ 'osbs', 0x2, "OSBS" ], #- http://www.prz.tu-berlin.de/~wolf/os-bs.html [ 'pqmagic', 0xef, "PQV" ], [ 'DocsBoot', 0x148, 'DocsBoot' ], [ 'system_commander', 0x1ad, "SYSCMNDRSYS" ], [ 'dos', 0xa0, "\x25\x03\x4E\x02\xCD\x13" ], [ 'dos', 0x60, "\xBB\x00\x7C\xB8\x01\x02\x57\xCD\x13\x5F\x73\x0C\x33\xC0\xCD\x13" ], #- nt's [ 'ranish', 0x100, "\x6A\x10\xB4\x42\x8B\xF4\xCD\x13\x8B\xE5\x73" ], ); sub typeOfMBR($) { typeFromMagic(devices::make($_[0]), @MBR_signatures) } sub compute_CHS($$) { my ($hd, $e) = @_; my @l = qw(cyl head sec); @$e{map { "start_$_" } @l} = $e->{start} || $e->{type} ? CHS2rawCHS(sector2CHS($hd, $e->{start})) : (0,0,0); @$e{map { "end_$_" } @l} = $e->{start} || $e->{type} ? CHS2rawCHS(sector2CHS($hd, $e->{start} + $e->{size} - 1)) : (0,0,0); 1; } sub CHS2rawCHS($$$) { my ($c, $h, $s) = @_; $c = min($c, 1023); #- no way to have a #cylinder >= 1024 ($c & 0xff, $h, $s | ($c >> 2 & 0xc0)); } # returns (cylinder, head, sector) sub sector2CHS($$) { my ($hd, $start) = @_; my ($s, $h); ($start, $s) = divide($start, $hd->{geom}{sectors}); ($start, $h) = divide($start, $hd->{geom}{heads}); ($start, $h, $s + 1); } sub get_geometry($) { my ($dev) = @_; my $g = ""; local *F; sysopen F, $dev, 0 or return; ioctl(F, c::HDIO_GETGEO(), $g) or return; my %geom; @geom{qw(heads sectors cylinders start)} = unpack "CCSL", $g; { geom => \%geom, totalsectors => $geom{heads} * $geom{sectors} * $geom{cylinders} }; } sub openit($$;$) { sysopen $_[1], $_[0]{file}, $_[2] || 0; } # cause kernel to re-read partition table sub kernel_read($) { my ($hd) = @_; local *F; openit($hd, \*F) or return 0; $hd->{rebootNeeded} = !ioctl(F, c::BLKRRPART(), 0); } sub read($$) { my ($hd, $sector) = @_; my $tmp; local *F; openit($hd, \*F) or return; c::lseek_sector(fileno(F), $sector, $offset) or die "reading of partition in sector $sector failed"; my @pt = map { sysread F, $tmp, psizeof($format) or return "error while reading partition table in sector $sector"; my %h; @h{@fields} = unpack $format, $tmp; \%h; } (1..$nb_primary); #- check magic number sysread F, $tmp, length $magic or die "error reading magic number"; $tmp eq $magic or die "bad magic number"; [ @pt ]; } # write the partition table (and extended ones) # for each entry, it uses fields: start, size, type, active sub write($$$) { my ($hd, $sector, $pt) = @_; local *F; openit($hd, \*F, 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 $nb_primary ] } } sub zero_MBR($) { my ($hd) = @_; $hd->{isDirty} = $hd->{needKernelReread} = 1; $hd->{primary} = clear_raw(); delete $hd->{extended}; } 1;