blob: 7724f38dba0bb42079bb115dfc98e940edced9e8 [file] [log] [blame]
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0-only
# ----------------------------------------------------------------------
# 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>
#
# ----------------------------------------------------------------------
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
if [ $? -ne 0 ]; then
# On ARM64, the kernel might be a PE file instead
# and output of file command might be something like following:
# $ file cuttlefish_assembly/vmlinux
# cuttlefish_assembly/vmlinux: MS-DOS executable PE32+ executable (EFI application) Aarch64 (stripped to external PDB), for MS Windows
# $
file $1 | grep -q "MS-DOS executable" || return 1
fi
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: $me <kernel-image>" >&2
exit 2
fi
# Prepare temp files:
tmp=$(mktemp /tmp/vmlinux-XXX)
trap "rm -f $tmp" 0
# 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 '\004\"M\030' xxx 'lz4 -d'
try_decompress '\002!L\030' xxx 'lz4 -d'
try_decompress '(\265/\375' xxx unzstd
# Finally check for uncompressed images or objects:
check_vmlinux $img
# Bail out:
echo "$me: Cannot find vmlinux." >&2