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-rw-r--r--perl-install/partition_table/dos.pm99
1 files changed, 99 insertions, 0 deletions
diff --git a/perl-install/partition_table/dos.pm b/perl-install/partition_table/dos.pm
new file mode 100644
index 000000000..a6ad4be76
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+++ b/perl-install/partition_table/dos.pm
@@ -0,0 +1,99 @@
+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 compute_CHS($$) {
+ my ($hd, $e) = @_;
+ my @l = qw(cyl head sec);
+ @$e{map { "start_$_" } @l} = $e->{start} || $e->{type} ? CHS2rawCHS($hd, sector2CHS($hd, $e->{start})) : (0,0,0);
+ @$e{map { "end_$_" } @l} = $e->{start} || $e->{type} ? CHS2rawCHS($hd, sector2CHS($hd, $e->{start} + $e->{size} - 1)) : (0,0,0);
+ 1;
+}
+
+sub CHS2rawCHS {
+ my ($hd, $c, $h, $s) = @_;
+ if ($c > 1023) {
+ #- no way to have a #cylinder >= 1024
+ $c = 1023;
+ $h = $hd->{geom}{heads} - 1;
+ $s = $hd->{geom}{sectors};
+ }
+ ($c & 0xff, $h, $s | ($c >> 2 & 0xc0));
+}
+
+# returns (cylinder, head, sector)
+sub sector2CHS {
+ my ($hd, $start) = @_;
+ my ($s, $h);
+ ($start, $s) = divide($start, $hd->{geom}{sectors});
+ ($start, $h) = divide($start, $hd->{geom}{heads});
+ ($start, $h, $s + 1);
+}
+
+sub read {
+ my ($hd, $sector) = @_;
+ my $tmp;
+
+ local *F; partition_table::raw::openit($hd, *F) or die "failed to open device";
+ c::lseek_sector(fileno(F), $sector, $offset) or die "reading of partition in sector $sector failed";
+
+ my @pt = map {
+ sysread F, $tmp, psizeof($format) or die "error while reading partition table in sector $sector";
+ my %h; @h{@fields} = unpack $format, $tmp;
+ \%h;
+ } (1..$nb_primary);
+
+ #- check magic number
+ sysread F, $tmp, length $magic or die "error reading magic number on disk $hd->{device}";
+ $tmp eq $magic or die "bad magic number on disk $hd->{device}";
+
+ [ @pt ];
+}
+
+# write the partition table (and extended ones)
+# for each entry, it uses fields: start, size, type, active
+sub write($$$;$) {
+ my ($hd, $sector, $pt) = @_;
+
+ #- handle testing for writing partition table on file only!
+ local *F;
+ if ($::testing) {
+ my $file = "/tmp/partition_table_$hd->{device}";
+ open F, ">$file" or die "error opening test file $file";
+ } else {
+ partition_table::raw::openit($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 ] } }
+
+1;