initscripts - Mageia fork of Fedora's Init Scripts

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-rw-r--r--

2 files changed, 33 insertions, 1 deletions

package resize_fat::fat; use diagnostics; use strict; use resize_fat::any; use resize_fat::io; 1; sub read($) { my ($fs) = @_; @{$fs->{fats}} = map { my $fat = eval { resize_fat::io::read($fs, $fs->{fat_offset} + $_ * $fs->{fat_size}, $fs->{fat_size}) }; $@ and die "reading fat #$_ failed"; vec($fat, 0, 8) == $fs->{media} or die "FAT $_ has invalid signature"; $fat; } (0 .. $fs->{nb_fats} - 1); $fs->{fat} = $fs->{fats}->[0]; my ($free, $bad, $used) = (0, 0, 0); for (my $i = 2; $i < $fs->{nb_clusters} + 2; $i++) { my $cluster = &next($fs, $i); if ($cluster == 0) { $free++; } elsif ($cluster == $resize_fat::bad_cluster_value) { $bad++; } else { $used++; } } @{$fs->{clusters}->{count}}{qw(free bad used)} = ($free, $bad, $used); } sub write($) { my ($fs) = @_; sysseek $fs->{fd}, $fs->{fat_offset}, 0 or die "write_fat: seek failed"; foreach (1..$fs->{nb_fats}) { syswrite $fs->{fd}, $fs->{fat}, $fs->{fat_size} or die "write_fat: write failed"; } } # allocates where all the clusters will be moved to. Clusters before cut_point # remain in the same position, however cluster that are part of a directory are # moved regardless (this is a mechanism to prevent data loss) (cut_point is the # first cluster that won't occur in the new fs) sub allocate_remap { my ($fs, $cut_point) = @_; my ($cluster, $new_cluster); my $remap = sub { $fs->{fat_remap}->[$cluster] = $new_cluster; }; my $get_new = sub { $new_cluster = get_free($fs); 0 < $new_cluster && $new_cluster < $cut_point or die "no free clusters"; set_eof($fs, $new_cluster); # mark as used #log::ld("resize_fat: [$cluster,", &next($fs, $cluster), "...]->$new_cluster..."); }; $fs->{fat_remap}->[0] = 0; $fs->{last_free_cluster} = 2; for ($cluster = 2; $cluster < $fs->{nb_clusters} + 2; $cluster++) { if ($cluster < $cut_point) { if ($fs->{fat_flag_map}->[$cluster] == $resize_fat::any::DIRECTORY) { &$get_new(); } else { $new_cluster = $cluster; } &$remap(); } elsif (!is_empty(&next($fs, $cluster))) { &$get_new(); &$remap(); } } } # updates the fat for the resized filesystem sub update { my ($fs) = @_; for (my $cluster = 2; $cluster < $fs->{nb_clusters} + 2; $cluster++) { if ($fs->{fat_flag_map}->[$cluster]) { my $old_next = &next($fs, $cluster); my $new = $fs->{fat_remap}->[$cluster]; my $new_next = $fs->{fat_remap}->[$old_next]; set_available($fs, $cluster); is_eof($old_next) ? set_eof($fs, $new) : set_next($fs, $new, $new_next); } } } # - compares the two FATs (one's a backup that should match) - skips first entry # - its just a signature (already checked above) NOTE: checks for cross-linking # are done in count.c sub check($) { my ($fs) = @_; foreach (@{$fs->{fats}}) { $_ eq $fs->{fats}->[0] or die "FAT tables do not match"; } } sub endianness16($) { (($_[0] & 0xff) << 8) + ($_[0] >> 8); } sub endianness($$) { my ($val, $nb_bits) = @_; my $r = 0; for (; $nb_bits > 0; $nb_bits -= 8) { $r <<= 8; $r += $val & 0xff; $val >>= 8; } $nb_bits < 0 and die "error: endianness only handle numbers divisible by 8"; $r; } sub next($$) { my ($fs, $cluster) = @_; $cluster > $fs->{nb_clusters} + 2 and die "fat::next: cluster $cluster outside filesystem"; endianness(vec($fs->{fat}, $cluster, $fs->{fs_type_size}), $fs->{fs_type_size}); } sub set_next($$$) { my ($fs, $cluster, $new_v) = @_; $cluster > $fs->{nb_clusters} + 2 and die "fat::set_next: cluster $cluster outside filesystem"; vec($fs->{fat}, $cluster, $fs->{fs_type_size}) = endianness($new_v, $fs->{fs_type_size}); } sub get_free($) { my ($fs) = @_; foreach (my $i = 0; $i < $fs->{nb_clusters}; $i++) { my $cluster = ($i + $fs->{last_free_cluster} - 2) % $fs->{nb_clusters} + 2; is_available(&next($fs, $cluster)) and return $fs->{last_free_cluster} = $cluster; } die "no free clusters"; } # returns true if <cluster> represents an EOF marker sub is_eof($) { my ($cluster) = @_; $cluster >= $resize_fat::bad_cluster_value; } sub set_eof($$) { my ($fs, $cluster) = @_; set_next($fs, $cluster, $resize_fat::bad_cluster_value + 1); } # returns true if <cluster> is empty. Note that this includes bad clusters. sub is_empty($) { my ($cluster) = @_; $cluster == 0 || $cluster == $resize_fat::bad_cluster_value; } # returns true if <cluster> is available. sub is_available($) { my ($cluster) = @_; $cluster == 0; } sub set_available($$) { my ($fs, $cluster) = @_; set_next($fs, $cluster, 0); }


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