Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
13me=${0##*/}
14
15check_vmlinux()
16{
17 if file "$1" | grep -q 'Linux kernel.*boot executable' ||
18 readelf -h "$1" > /dev/null 2>&1
19 then
20 cat "$1"
21 echo "$me: Extracted vmlinux using '$2' from offset $3" >&2
22 exit 0
23 fi
24}
25
26try_decompress()
27{
28 # The obscure use of the "tr" filter is to work around older versions of
29 # "grep" that report the byte offset of the line instead of the pattern.
30
31 # Try to find the header ($1) and decompress from here
32 for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"`
33 do
34 pos=${pos%%:*}
35 tail -c+$pos "$img" | $3 > $tmp 2> /dev/null
36 check_vmlinux $tmp "$3" $pos
37 done
38}
39
40# Check invocation:
41img=$1
42if [ $# -ne 1 -o ! -s "$img" ]
43then
44 echo "Usage: $me <kernel-image>" >&2
45 exit 2
46fi
47
48# Prepare temp files:
49tmp=$(mktemp /tmp/vmlinux-XXX)
50trap "rm -f $tmp" 0
51
52# That didn't work, so retry after decompression.
53try_decompress '\037\213\010' xy gunzip
54try_decompress '\3757zXZ\000' abcde unxz
55try_decompress 'BZh' xy bunzip2
56try_decompress '\135\0\0\0' xxx unlzma
57try_decompress '\211\114\132' xy 'lzop -d'
58try_decompress '\002!L\030' xxx 'lz4 -d'
59try_decompress '(\265/\375' xxx unzstd
60
61# Finally check for uncompressed images or objects:
62check_vmlinux "$img" cat 0
63
64# Bail out:
65echo "$me: Cannot find vmlinux." >&2