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| 1 | +#!/usr/bin/env perl |
| 2 | +# ---------------------------------------------------------------------- |
| 3 | +# knlinfo by Phil Elwell for Raspberry Pi |
| 4 | +# |
| 5 | +# (c) 2014,2015 Raspberry Pi (Trading) Limited <[email protected]> |
| 6 | +# |
| 7 | +# Licensed under the terms of the GNU General Public License. |
| 8 | +# ---------------------------------------------------------------------- |
| 9 | + |
| 10 | +use strict; |
| 11 | +use integer; |
| 12 | + |
| 13 | +use Fcntl ":seek"; |
| 14 | + |
| 15 | +my $trailer_magic = 'RPTL'; |
| 16 | + |
| 17 | +my %atom_formats = |
| 18 | +( |
| 19 | + 'DTOK' => \&format_bool, |
| 20 | + 'KVer' => \&format_string, |
| 21 | + '283x' => \&format_bool, |
| 22 | +); |
| 23 | + |
| 24 | +if (@ARGV != 1) |
| 25 | +{ |
| 26 | + print ("Usage: knlinfo <kernel image>\n"); |
| 27 | + exit(1); |
| 28 | +} |
| 29 | + |
| 30 | +my $kernel_file = $ARGV[0]; |
| 31 | + |
| 32 | + |
| 33 | +my ($atoms, $pos) = read_trailer($kernel_file); |
| 34 | + |
| 35 | +exit(1) if (!$atoms); |
| 36 | + |
| 37 | +printf("Kernel trailer found at %d/0x%x:\n", $pos, $pos); |
| 38 | + |
| 39 | +foreach my $atom (@$atoms) |
| 40 | +{ |
| 41 | + printf(" %s: %s\n", $atom->[0], format_atom($atom)); |
| 42 | +} |
| 43 | + |
| 44 | +exit(0); |
| 45 | + |
| 46 | +sub read_trailer |
| 47 | +{ |
| 48 | + my ($kernel_file) = @_; |
| 49 | + my $fh; |
| 50 | + |
| 51 | + if (!open($fh, '<', $kernel_file)) |
| 52 | + { |
| 53 | + print ("* Failed to open '$kernel_file'\n"); |
| 54 | + return undef; |
| 55 | + } |
| 56 | + |
| 57 | + if (!seek($fh, -12, SEEK_END)) |
| 58 | + { |
| 59 | + print ("* seek error in '$kernel_file'\n"); |
| 60 | + return undef; |
| 61 | + } |
| 62 | + |
| 63 | + my $last_bytes; |
| 64 | + sysread($fh, $last_bytes, 12); |
| 65 | + |
| 66 | + my ($trailer_len, $data_len, $magic) = unpack('VVa4', $last_bytes); |
| 67 | + |
| 68 | + if (($magic ne $trailer_magic) || ($data_len != 4)) |
| 69 | + { |
| 70 | + print ("* no trailer\n"); |
| 71 | + return undef; |
| 72 | + } |
| 73 | + if (!seek($fh, -12, SEEK_END)) |
| 74 | + { |
| 75 | + print ("* seek error in '$kernel_file'\n"); |
| 76 | + return undef; |
| 77 | + } |
| 78 | + |
| 79 | + $trailer_len -= 12; |
| 80 | + |
| 81 | + while ($trailer_len > 0) |
| 82 | + { |
| 83 | + if ($trailer_len < 8) |
| 84 | + { |
| 85 | + print ("* truncated atom header in trailer\n"); |
| 86 | + return undef; |
| 87 | + } |
| 88 | + if (!seek($fh, -8, SEEK_CUR)) |
| 89 | + { |
| 90 | + print ("* seek error in '$kernel_file'\n"); |
| 91 | + return undef; |
| 92 | + } |
| 93 | + $trailer_len -= 8; |
| 94 | + |
| 95 | + my $atom_hdr; |
| 96 | + sysread($fh, $atom_hdr, 8); |
| 97 | + my ($atom_len, $atom_type) = unpack('Va4', $atom_hdr); |
| 98 | + |
| 99 | + if ($trailer_len < $atom_len) |
| 100 | + { |
| 101 | + print ("* truncated atom data in trailer\n"); |
| 102 | + return undef; |
| 103 | + } |
| 104 | + |
| 105 | + my $rounded_len = (($atom_len + 3) & ~3); |
| 106 | + if (!seek($fh, -(8 + $rounded_len), SEEK_CUR)) |
| 107 | + { |
| 108 | + print ("* seek error in '$kernel_file'\n"); |
| 109 | + return undef; |
| 110 | + } |
| 111 | + $trailer_len -= $rounded_len; |
| 112 | + |
| 113 | + my $atom_data; |
| 114 | + sysread($fh, $atom_data, $atom_len); |
| 115 | + |
| 116 | + if (!seek($fh, -$atom_len, SEEK_CUR)) |
| 117 | + { |
| 118 | + print ("* seek error in '$kernel_file'\n"); |
| 119 | + return undef; |
| 120 | + } |
| 121 | + |
| 122 | + push @$atoms, [ $atom_type, $atom_data ]; |
| 123 | + } |
| 124 | + |
| 125 | + if (($$atoms[-1][0] eq "\x00\x00\x00\x00") && |
| 126 | + ($$atoms[-1][1] eq "")) |
| 127 | + { |
| 128 | + pop @$atoms; |
| 129 | + } |
| 130 | + else |
| 131 | + { |
| 132 | + print ("* end marker missing from trailer\n"); |
| 133 | + } |
| 134 | + |
| 135 | + return ($atoms, tell($fh)); |
| 136 | +} |
| 137 | + |
| 138 | +sub format_atom |
| 139 | +{ |
| 140 | + my ($atom) = @_; |
| 141 | + |
| 142 | + my $format_func = $atom_formats{$atom->[0]} || \&format_hex; |
| 143 | + return $format_func->($atom->[1]); |
| 144 | +} |
| 145 | + |
| 146 | +sub format_bool |
| 147 | +{ |
| 148 | + my ($data) = @_; |
| 149 | + return unpack('V', $data) ? 'true' : 'false'; |
| 150 | +} |
| 151 | + |
| 152 | +sub format_int |
| 153 | +{ |
| 154 | + my ($data) = @_; |
| 155 | + return unpack('V', $data); |
| 156 | +} |
| 157 | + |
| 158 | +sub format_string |
| 159 | +{ |
| 160 | + my ($data) = @_; |
| 161 | + return '"'.$data.'"'; |
| 162 | +} |
| 163 | + |
| 164 | +sub format_hex |
| 165 | +{ |
| 166 | + my ($data) = @_; |
| 167 | + return unpack('H*', $data); |
| 168 | +} |
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