Root/scripts/extract-vmlinux

Source at commit cdde9cf73945d547acd3e96f9508c79e84ad0bf1 created 9 years 4 months ago.
By Maarten ter Huurne, MMC: JZ4740: Added support for CPU frequency changing
1#!/bin/sh
2# ----------------------------------------------------------------------
3# extract-vmlinux - Extract uncompressed vmlinux from a kernel image
4#
5# Inspired from extract-ikconfig
6# (c) 2009,2010 Dick Streefland <dick@streefland.net>
7#
8# (c) 2011 Corentin Chary <corentin.chary@gmail.com>
9#
10# Licensed under the GNU General Public License, version 2 (GPLv2).
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 || return 1
19
20    cat $1
21    exit 0
22}
23
24try_decompress()
25{
26    # The obscure use of the "tr" filter is to work around older versions of
27    # "grep" that report the byte offset of the line instead of the pattern.
28
29    # Try to find the header ($1) and decompress from here
30    for pos in `tr "$1\n$2" "\n$2=" < "$img" | grep -abo "^$2"`
31    do
32        pos=${pos%%:*}
33        tail -c+$pos "$img" | $3 > $tmp 2> /dev/null
34        check_vmlinux $tmp
35    done
36}
37
38# Check invocation:
39me=${0##*/}
40img=$1
41if [ $# -ne 1 -o ! -s "$img" ]
42then
43    echo "Usage: $me <kernel-image>" >&2
44    exit 2
45fi
46
47# Prepare temp files:
48tmp=$(mktemp /tmp/vmlinux-XXX)
49trap "rm -f $tmp" 0
50
51# Initial attempt for uncompressed images or objects:
52check_vmlinux $img
53
54# That didn't work, so retry after decompression.
55try_decompress '\037\213\010' xy gunzip
56try_decompress '\3757zXZ\000' abcde unxz
57try_decompress 'BZh' xy bunzip2
58try_decompress '\135\0\0\0' xxx unlzma
59try_decompress '\211\114\132' xy 'lzop -d'
60
61# Bail out:
62echo "$me: Cannot find vmlinux." >&2
63

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