diff options
Diffstat (limited to 'perl-install/resize_fat/fat.pm')
| -rw-r--r-- | perl-install/resize_fat/fat.pm | 135 |
1 files changed, 135 insertions, 0 deletions
diff --git a/perl-install/resize_fat/fat.pm b/perl-install/resize_fat/fat.pm new file mode 100644 index 000000000..a3372a905 --- /dev/null +++ b/perl-install/resize_fat/fat.pm @@ -0,0 +1,135 @@ +package resize_fat::fat; # $Id: fat.pm 210307 2004-12-13 15:56:00Z tvignaud $ + +use diagnostics; +use strict; + +use resize_fat::any; +use resize_fat::io; +use resize_fat::c_rewritten qw(next set_next); + +sub read($) { + my ($fs) = @_; + + resize_fat::c_rewritten::read_fat(fileno $fs->{fd}, $fs->{fat_offset}, $fs->{fat_size}, $fs->{media}); + + @{$fs->{clusters}{count}}{qw(free bad used)} = + resize_fat::c_rewritten::scan_fat($fs->{nb_clusters}, $fs->{fs_type_size}); +} + +sub write($) { + my ($fs) = @_; + + sysseek $fs->{fd}, $fs->{fat_offset}, 0 or die "write_fat: seek failed"; + foreach (1..$fs->{nb_fats}) { + resize_fat::c_rewritten::write_fat(fileno $fs->{fd}, $fs->{fat_size}); + } +} + + + +#- allocates where all the clusters will be moved to. Clusters before cut_point +#- remain in the same position, however cluster that are part of a directory are +#- moved regardless (this is a mechanism to prevent data loss) (cut_point is the +#- first cluster that will not occur in the new fs) +sub allocate_remap { + my ($fs, $cut_point) = @_; + my ($cluster, $new_cluster); + my $remap = sub { resize_fat::c_rewritten::set_fat_remap($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..."); + }; + + #- this must call allocate_fat_remap that zeroes the buffer allocated. + resize_fat::c_rewritten::allocate_fat_remap($fs->{nb_clusters} + 2); + + $fs->{last_free_cluster} = 2; + for ($cluster = 2; $cluster < $fs->{nb_clusters} + 2; $cluster++) { + if ($cluster < $cut_point) { + if (resize_fat::c_rewritten::flag($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; $cluster++) { + if (resize_fat::c_rewritten::flag($cluster)) { + my $old_next = &next($fs, $cluster); + my $new = resize_fat::c_rewritten::fat_remap($cluster); + my $new_next = resize_fat::c_rewritten::fat_remap($old_next); + + set_available($fs, $cluster); + + is_eof($old_next) ? + set_eof($fs, $new) : + set_next($fs, $new, $new_next); + } + } +} + + +sub endianness16($) { (($_[0] & 0xff) << 8) + ($_[0] >> 8) } +sub endianness($$) { + my ($val, $nb_bits) = @_; + my $r = 0; + for (; $nb_bits > 0; $nb_bits -= 8) { + $r = $r << 8; + $r += $val & 0xff; + $val = $val >> 8; + } + $nb_bits < 0 and die "error: endianness only handle numbers divisible by 8"; + $r; +} + + + +sub get_free($) { + my ($fs) = @_; + for (my $i = 0; $i < $fs->{nb_clusters}; $i++) { + my $cluster = ($i + $fs->{last_free_cluster} - 2) % $fs->{nb_clusters} + 2; + is_available(&next($fs, $cluster)) and return $fs->{last_free_cluster} = $cluster; + } + die "no free clusters"; +} + +#- returns true if <cluster> represents an EOF marker +sub is_eof($) { + my ($cluster) = @_; + $cluster >= $resize_fat::bad_cluster_value; +} +sub set_eof($$) { + 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); +} + +1; |