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68 lines
1.7 KiB
68 lines
1.7 KiB
#!/bin/sh |
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# ---------------------------------------------------------------------- |
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# extract-ikconfig - Extract the .config file from a kernel image |
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# |
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# This will only work when the kernel was compiled with CONFIG_IKCONFIG. |
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# |
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# The obscure use of the "tr" filter is to work around older versions of |
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# "grep" that report the byte offset of the line instead of the pattern. |
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# |
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# (c) 2009,2010 Dick Streefland <[email protected]> |
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# Licensed under the terms of the GNU General Public License. |
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# ---------------------------------------------------------------------- |
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cf1='IKCFG_ST\037\213\010' |
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cf2='0123456789' |
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dump_config() |
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{ |
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if pos=`tr "$cf1\n$cf2" "\n$cf2=" < "$1" | grep -abo "^$cf2"` |
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then |
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pos=${pos%%:*} |
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tail -c+$(($pos+8)) "$1" | zcat > $tmp1 2> /dev/null |
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if [ $? != 1 ] |
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then # exit status must be 0 or 2 (trailing garbage warning) |
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cat $tmp1 |
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exit 0 |
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fi |
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fi |
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} |
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try_decompress() |
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{ |
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for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` |
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do |
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pos=${pos%%:*} |
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tail -c+$pos "$img" | $3 > $tmp2 2> /dev/null |
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dump_config $tmp2 |
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done |
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} |
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# Check invocation: |
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me=${0##*/} |
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img=$1 |
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if [ $# -ne 1 -o ! -s "$img" ] |
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then |
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echo "Usage: $me <kernel-image>" >&2 |
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exit 2 |
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fi |
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# Prepare temp files: |
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tmp1=/tmp/ikconfig$$.1 |
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tmp2=/tmp/ikconfig$$.2 |
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trap "rm -f $tmp1 $tmp2" 0 |
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# Initial attempt for uncompressed images or objects: |
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dump_config "$img" |
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# That didn't work, so retry after decompression. |
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try_decompress '\037\213\010' xy gunzip |
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try_decompress '\3757zXZ\000' abcde unxz |
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try_decompress 'BZh' xy bunzip2 |
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try_decompress '\135\0\0\0' xxx unlzma |
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try_decompress '\211\114\132' xy 'lzop -d' |
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try_decompress '\002\041\114\030' xyy 'lz4 -d -l' |
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# Bail out: |
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echo "$me: Cannot find kernel config." >&2 |
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exit 1
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