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 19 if [ $? -ne 0 ]; then 20 # On ARM64, the kernel might be a PE file instead 21 file $1 | grep -q "MS-DOS executable$" || return 1 22 fi 23 24 cat $1 25 exit 0 26} 27 28try_decompress() 29{ 30 # The obscure use of the "tr" filter is to work around older versions of 31 # "grep" that report the byte offset of the line instead of the pattern. 32 33 # Try to find the header ($1) and decompress from here 34 for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"` 35 do 36 pos=${pos%%:*} 37 tail -c+$pos "$img" | $3 > $tmp 2> /dev/null 38 check_vmlinux $tmp 39 done 40} 41 42# Check invocation: 43me=${0##*/} 44img=$1 45if [ $# -ne 1 -o ! -s "$img" ] 46then 47 echo "Usage: $me <kernel-image>" >&2 48 exit 2 49fi 50 51# Prepare temp files: 52tmp=$(mktemp /tmp/vmlinux-XXX) 53trap "rm -f $tmp" 0 54 55# That didn't work, so retry after decompression. 56try_decompress '\037\213\010' xy gunzip 57try_decompress '\3757zXZ\000' abcde unxz 58try_decompress 'BZh' xy bunzip2 59try_decompress '\135\0\0\0' xxx unlzma 60try_decompress '\211\114\132' xy 'lzop -d' 61try_decompress '\004\"M\030' xxx 'lz4 -d' 62try_decompress '\002!L\030' xxx 'lz4 -d' 63try_decompress '(\265/\375' xxx unzstd 64 65# Finally check for uncompressed images or objects: 66check_vmlinux $img 67 68# Bail out: 69echo "$me: Cannot find vmlinux." >&2 70