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Commit | Line | Data |
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1da177e4 | 1 | #!/bin/sh |
7b76bfc8 DS |
2 | # ---------------------------------------------------------------------- |
3 | # extract-ikconfig - Extract the .config file from a kernel image | |
4 | # | |
5 | # This will only work when the kernel was compiled with CONFIG_IKCONFIG. | |
6 | # | |
7 | # The obscure use of the "tr" filter is to work around older versions of | |
8 | # "grep" that report the byte offset of the line instead of the pattern. | |
9 | # | |
532cf290 | 10 | # (c) 2009,2010 Dick Streefland <dick@streefland.net> |
7b76bfc8 DS |
11 | # Licensed under the terms of the GNU General Public License. |
12 | # ---------------------------------------------------------------------- | |
13 | ||
7b76bfc8 DS |
14 | cf1='IKCFG_ST\037\213\010' |
15 | cf2='0123456789' | |
16 | ||
17 | dump_config() | |
1da177e4 | 18 | { |
7b76bfc8 DS |
19 | if pos=`tr "$cf1\n$cf2" "\n$cf2=" < "$1" | grep -abo "^$cf2"` |
20 | then | |
21 | pos=${pos%%:*} | |
532cf290 DS |
22 | tail -c+$(($pos+8)) "$1" | zcat > $tmp1 2> /dev/null |
23 | if [ $? != 1 ] | |
24 | then # exit status must be 0 or 2 (trailing garbage warning) | |
25 | cat $tmp1 | |
26 | exit 0 | |
27 | fi | |
1da177e4 LT |
28 | fi |
29 | } | |
30 | ||
532cf290 DS |
31 | try_decompress() |
32 | { | |
33 | for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` | |
34 | do | |
35 | pos=${pos%%:*} | |
36 | tail -c+$pos "$img" | $3 > $tmp2 2> /dev/null | |
37 | dump_config $tmp2 | |
38 | done | |
39 | } | |
40 | ||
7b76bfc8 DS |
41 | # Check invocation: |
42 | me=${0##*/} | |
43 | img=$1 | |
44 | if [ $# -ne 1 -o ! -s "$img" ] | |
1da177e4 | 45 | then |
7b76bfc8 DS |
46 | echo "Usage: $me <kernel-image>" >&2 |
47 | exit 2 | |
1da177e4 LT |
48 | fi |
49 | ||
532cf290 DS |
50 | # Prepare temp files: |
51 | tmp1=/tmp/ikconfig$$.1 | |
52 | tmp2=/tmp/ikconfig$$.2 | |
53 | trap "rm -f $tmp1 $tmp2" 0 | |
54 | ||
7b76bfc8 DS |
55 | # Initial attempt for uncompressed images or objects: |
56 | dump_config "$img" | |
57 | ||
532cf290 | 58 | # That didn't work, so retry after decompression. |
ab94e466 DS |
59 | try_decompress '\037\213\010' xy gunzip |
60 | try_decompress '\3757zXZ\000' abcde unxz | |
61 | try_decompress 'BZh' xy bunzip2 | |
62 | try_decompress '\135\0\0\0' xxx unlzma | |
63 | try_decompress '\211\114\132' xy 'lzop -d' | |
99b2cdde | 64 | try_decompress '\002\041\114\030' xyy 'lz4 -d -l' |
7b76bfc8 DS |
65 | |
66 | # Bail out: | |
67 | echo "$me: Cannot find kernel config." >&2 | |
1da177e4 | 68 | exit 1 |