linux-yocto/scripts/extract-vmlinux
Adam Borowski 47a18a2dab scripts: teach extract-vmlinux about LZ4 and ZSTD
Note that the LZ4 signature is different than that of modern LZ4 as we
use the "legacy" format which suffers from some downsides like inability
to disable compression.

Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
2018-07-08 09:32:32 +09:00

1.7 KiB
Executable File

#!/bin/sh

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extract-vmlinux - Extract uncompressed vmlinux from a kernel image

Inspired from extract-ikconfig

(c) 2009,2010 Dick Streefland dick@streefland.net

(c) 2011 Corentin Chary corentin.chary@gmail.com

Licensed under the GNU General Public License, version 2 (GPLv2).

----------------------------------------------------------------------

check_vmlinux() { # Use readelf to check if it's a valid ELF # TODO: find a better to way to check that it's really vmlinux # and not just an elf readelf -h $1 > /dev/null 2>&1 || return 1

cat $1
exit 0

}

try_decompress() { # The obscure use of the "tr" filter is to work around older versions of # "grep" that report the byte offset of the line instead of the pattern.

# Try to find the header ($1) and decompress from here
for	pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"`
do
	pos=${pos%%:*}
	tail -c+$pos "$img" | $3 > $tmp 2> /dev/null
	check_vmlinux $tmp
done

}

Check invocation:

me=${0##*/} img=$1 if [ $# -ne 1 -o ! -s "$img" ] then echo "Usage: $me " >&2 exit 2 fi

Prepare temp files:

tmp=$(mktemp /tmp/vmlinux-XXX) trap "rm -f $tmp" 0

Initial attempt for uncompressed images or objects:

check_vmlinux $img

That didn't work, so retry after decompression.

try_decompress '\037\213\010' xy gunzip try_decompress '\3757zXZ\000' abcde unxz try_decompress 'BZh' xy bunzip2 try_decompress '\135\0\0\0' xxx unlzma try_decompress '\211\114\132' xy 'lzop -d' try_decompress '\002!L\030' xxx 'lz4 -d' try_decompress '(\265/\375' xxx unzstd

Bail out:

echo "$me: Cannot find vmlinux." >&2