99b2cdde83
Support for kernel image LZ4 compression was added around 3.11, but not the corresponding kernel .config extraction. This makes possible extracting the kernel config for LZ4-compressed kernels you're not running, or the current LZ4-compressed kernel if compiled without /proc/config.gz support. Signed-off-by: Alex Pilon <alp+linux@alexpilon.ca> Signed-off-by: Michal Marek <mmarek@suse.cz>
69 lines
1.7 KiB
Bash
Executable File
69 lines
1.7 KiB
Bash
Executable File
#!/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 <dick@streefland.net>
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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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