1 files changed, 71 insertions, 0 deletions
diff --git a/extract-vmlinux b/extract-vmlinux
new file mode 100755
index 000000000000..15e8f7d0a8cd
--- /dev/null
+++ b/extract-vmlinux
@@ -0,0 +1,71 @@
+#!/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
+	case "$2" in
+	0|"")
+		readelf -h $1 > /dev/null 2>&1 || return 1
+		;;
+	1)
+	# For ARCH like armel/armhf, vmlinux is not ELF, so we skip the check
+		;;
+	esac
+
+	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
+		test $? -eq 0 && check_vmlinux $tmp 1
+	done
+}
+
+# Check invocation:
+me=${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 --single-stream"
+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
+
+# Finally check for uncompressed images or objects:
+check_vmlinux $img
+
+# Bail out:
+echo "$me: Cannot find vmlinux." >&2