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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
|
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 geometry_to_string {
my ($geom) = @_;
"$geom->{cylinders}/$geom->{heads}/$geom->{sectors}";
}
sub last_usable_sector {
my ($hd) = @_;
#- do not use totalsectors, see gi/docs/Partition-ends-after-end-of-disk.txt for more
$hd->{geom}{sectors} * $hd->{geom}{heads} * $hd->{geom}{cylinders};
}
sub get_rawCHS {
my ($part) = @_;
[ $part->{start_cyl}, $part->{start_head}, $part->{start_sec} ],
[ $part->{end_cyl}, $part->{end_head}, $part->{end_sec} ];
}
sub set_rawCHS {
my ($part, $raw_chs_start, $raw_chs_end) = @_;
($part->{start_cyl}, $part->{start_head}, $part->{start_sec}) = @$raw_chs_start;
($part->{end_cyl}, $part->{end_head}, $part->{end_sec}) = @$raw_chs_end;
}
sub compute_CHS {
my ($hd, $part) = @_;
my ($chs_start, $chs_end) = CHS_from_part_linear($hd->{geom}, $part);
set_rawCHS($part, $chs_start ? CHS2rawCHS($hd->{geom}, $chs_start) : [0,0,0],
$chs_end ? CHS2rawCHS($hd->{geom}, $chs_end) : [0,0,0]);
}
sub CHS_from_part_rawCHS {
my ($part) = @_;
$part->{start} || $part->{type} or return;
my ($raw_chs_start, $raw_chs_end) = get_rawCHS($part);
rawCHS2CHS($raw_chs_start), rawCHS2CHS($raw_chs_end);
}
sub CHS_from_part_linear {
my ($geom, $part) = @_;
$part->{start} || $part->{type} or return;
sector2CHS($geom, $part->{start}), sector2CHS($geom, $part->{start} + $part->{size} - 1);
}
sub rawCHS2CHS {
my ($chs) = @_;
my ($c, $h, $s) = @$chs;
[ $c | (($s & 0xc0) << 2), $h, ($s & 0x3f) - 1 ];
}
sub CHS2rawCHS {
my ($geom, $chs) = @_;
my ($c, $h, $s) = @$chs;
if ($c > 1023) {
#- no way to have a #cylinder >= 1024
$c = 1023;
$h = $geom->{heads} - 1;
$s = $geom->{sectors} - 1;
}
[ $c & 0xff, $h, ($s + 1) | (($c >> 2) & 0xc0) ];
}
# returns (cylinder, head, sector)
sub sector2CHS {
my ($geom, $start) = @_;
my ($s, $h);
($start, $s) = divide($start, $geom->{sectors});
($start, $h) = divide($start, $geom->{heads});
[ $start, $h, $s ];
}
sub is_geometry_valid_for_the_partition_table {
my ($hd, $geom, $no_log) = @_;
every {
my ($chs_start_v1, $chs_end_v1) = map { join(',', @$_) } CHS_from_part_rawCHS($_) or next;
my ($chs_start_v2, $chs_end_v2) = map { join(',', @$_) } map { [ min($_->[0], 1023), $_->[1], $_->[2] ] } CHS_from_part_linear($geom, $_);
if (!$no_log) {
$chs_start_v1 eq $chs_start_v2 or log::l("check_geometry_using_the_partition_table failed for ($_->{device}, $_->{start}): $chs_start_v1 vs $chs_start_v2 with geometry " . geometry_to_string($geom));
$chs_end_v1 eq $chs_end_v2 or log::l("check_geometry_using_the_partition_table failed for ($_->{device}, " . ($_->{start} + $_->{size} - 1) . "): $chs_end_v1 vs $chs_end_v2 with geometry " . geometry_to_string($geom));
}
$chs_start_v1 eq $chs_start_v2 && $chs_end_v1 eq $chs_end_v2;
} @{$hd->{primary}{normal} || []};
}
#- from parted, thanks!
my @valid_nb_sectors = (63, 61, 48, 32, 16);
my @valid_nb_heads = (255, 192, 128, 96, 64, 61, 32, 17, 16);
sub guess_geometry_from_partition_table {
my ($hd) = @_;
my @chss = map { CHS_from_part_rawCHS($_) } @{$hd->{primary}{normal} || []} or return { empty => 1 };
my ($nb_heads, $nb_sectors) = (max(map { $_->[1] } @chss) + 1, max(map { $_->[2] } @chss) + 1);
my $geom = { sectors => $nb_sectors, heads => $nb_heads };
partition_table::raw::compute_nb_cylinders($geom, $hd->{totalsectors});
log::l("guess_geometry_from_partition_table $hd->{device}: " . geometry_to_string($geom));
member($geom->{heads}, @valid_nb_heads) && member($geom->{sectors}, @valid_nb_sectors) or return { invalid => 1 };
$geom;
}
sub try_every_geometry {
my ($hd) = @_;
my $geom = {};
foreach (@valid_nb_sectors) {
$geom->{sectors} = $_;
foreach (@valid_nb_heads) {
$geom->{heads} = $_;
if (is_geometry_valid_for_the_partition_table($hd, $geom, 1)) {
partition_table::raw::compute_nb_cylinders($geom, $hd->{totalsectors});
log::l("try_every_geometry $hd->{device}: found " . geometry_to_string($geom));
return $geom;
}
}
}
log::l("$hd->{device}: argh! no geometry exists for this partition table");
undef;
}
sub set_best_geometry_for_the_partition_table {
my ($hd) = @_;
my $guessed_geom = guess_geometry_from_partition_table($hd);
if ($guessed_geom->{empty}) {
log::l("$hd->{device}: would need looking at BIOS info to find out geometry");
return;
}
my $default_ok = is_geometry_valid_for_the_partition_table($hd, $hd->{geom}, 0);
if ($guessed_geom->{invalid}) {
log::l("$hd->{device}: no valid geometry guessed from partition table");
$default_ok and return;
$guessed_geom = try_every_geometry($hd) or return;
}
if ($guessed_geom->{heads} == $hd->{geom}{heads} && $guessed_geom->{sectors} == $hd->{geom}{sectors}) {
# cool!
} else {
my $guessed_ok = is_geometry_valid_for_the_partition_table($hd, $guessed_geom, 0);
if ($default_ok && $guessed_ok) {
#- oh my!?
log::l("$hd->{device}: both guessed and default are valid??? " . geometry_to_string($hd->{geom}) . " vs " . geometry_to_string($guessed_geom));
} elsif ($default_ok) {
log::l("$hd->{device}: keeping default geometry " . geometry_to_string($hd->{geom}));
} elsif ($guessed_ok) {
log::l("$hd->{device}: using guessed geometry " . geometry_to_string($guessed_geom) . " instead of " . geometry_to_string($hd->{geom}));
put_in_hash($hd->{geom}, $guessed_geom);
} else {
log::l("$hd->{device}: argh! no valid geometry found");
}
}
}
sub read {
my ($hd, $sector) = @_;
my $tmp;
my $F = partition_table::raw::openit($hd) 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!
my $F;
if ($::testing) {
my $file = "/tmp/partition_table_$hd->{device}";
open $F, ">$file" or die "error opening test file $file";
} else {
$F = partition_table::raw::openit($hd, 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;
|
