1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
|
package resize_fat::fat; # $Id$
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;
|
