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1 files changed, 86 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..1b25a8f0b
--- /dev/null
+++ b/perl-install/partition_table_dos.pm
@@ -0,0 +1,86 @@
+package partition_table_dos;
+
+use diagnostics;
+use strict;
+use vars qw(@ISA);
+
+@ISA = qw(partition_table_raw);
+
+use common qw(:common :system :file);
+use partition_table_raw;
+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);
+
+sub hasExtended { 1 }
+
+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($$) {
+    my ($hd, $start) = @_;
+    my ($s, $h);
+    ($start, $s) = divide($start, $hd->{geom}{sectors});
+    ($start, $h) = divide($start, $hd->{geom}{heads});
+    ($start, $h, $s + 1);
+}
+
+sub read($$) {
+    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";
+    $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, $pt) = @_;
+
+    local *F; partition_table_raw::openit($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;