Add a script to extract vmlinux
Bug: 123595327
Test: build
Change-Id: I26f0dc3b800a47f0d5fcb0b64bbe08b59f5f7b6e
(cherry picked from commit 264c8e246d283914dce71e584847f36d425a0489)
diff --git a/Android.bp b/Android.bp
index 51f545d..8e7d40a 100644
--- a/Android.bp
+++ b/Android.bp
@@ -1,4 +1,3 @@
-//
// Copyright (C) 2017 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
@@ -20,3 +19,9 @@
host_supported: true,
defaults: ["cuttlefish_recovery_available"],
}
+
+cc_prebuilt_binary {
+ name: "extract-vmlinux",
+ srcs: ["scripts/extract-vmlinux"],
+ defaults: ["cuttlefish_host_only"],
+}
diff --git a/scripts/extract-vmlinux b/scripts/extract-vmlinux
new file mode 100755
index 0000000..5061abc
--- /dev/null
+++ b/scripts/extract-vmlinux
@@ -0,0 +1,62 @@
+#!/bin/sh
+# ----------------------------------------------------------------------
+# 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>
+#
+# Licensed under the GNU General Public License, version 2 (GPLv2).
+# ----------------------------------------------------------------------
+
+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 || return 1
+
+ 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
+
+# Initial attempt for uncompressed images or objects:
+check_vmlinux $img
+
+# That didn't work, so retry after decompression.
+try_decompress '\037\213\010' xy gunzip
+try_decompress '\3757zXZ\000' abcde unxz
+try_decompress 'BZh' xy bunzip2
+try_decompress '\135\0\0\0' xxx unlzma
+try_decompress '\211\114\132' xy 'lzop -d'
+
+# Bail out:
+echo "$me: Cannot find vmlinux." >&2
