1#!/bin/sh 2# SPDX-License-Identifier: GPL-2.0-only 3# ---------------------------------------------------------------------- 4# extract-vmlinux - Extract uncompressed vmlinux from a kernel image 5# 6# Inspired from extract-ikconfig 7# (c) 2009,2010 Dick Streefland <dick@streefland.net> 8# 9# (c) 2011 Corentin Chary <corentin.chary@gmail.com> 10# 11# ---------------------------------------------------------------------- 12 13check_vmlinux() 14{ 15 # Use readelf to check if it's a valid ELF 16 # TODO: find a better to way to check that it's really vmlinux 17 # and not just an elf 18 readelf -h $1 > /dev/null 2>&1 || return 1 19 20 cat $1 21 exit 0 22} 23 24try_decompress() 25{ 26 # The obscure use of the "tr" filter is to work around older versions of 27 # "grep" that report the byte offset of the line instead of the pattern. 28 29 # Try to find the header ($1) and decompress from here 30 for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` 31 do 32 pos=${pos%%:*} 33 tail -c+$pos "$img" | $3 > $tmp 2> /dev/null 34 check_vmlinux $tmp 35 done 36} 37 38# Check invocation: 39me=${0##*/} 40img=$1 41if [ $# -ne 1 -o ! -s "$img" ] 42then 43 echo "Usage: $me <kernel-image>" >&2 44 exit 2 45fi 46 47# Prepare temp files: 48tmp=$(mktemp /tmp/vmlinux-XXX) 49trap "rm -f $tmp" 0 50 51# That didn't work, so retry after decompression. 52try_decompress '\037\213\010' xy gunzip 53try_decompress '\3757zXZ\000' abcde unxz 54try_decompress 'BZh' xy bunzip2 55try_decompress '\135\0\0\0' xxx unlzma 56try_decompress '\211\114\132' xy 'lzop -d' 57try_decompress '\002!L\030' xxx 'lz4 -d' 58try_decompress '(\265/\375' xxx unzstd 59 60# Finally check for uncompressed images or objects: 61check_vmlinux $img 62 63# Bail out: 64echo "$me: Cannot find vmlinux." >&2 65