github.com/cilium/ebpf@v0.10.0/testdata/extract-vmlinux (about)

     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  
    13  check_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  
    24  try_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 $tmp
    35  	done
    36  }
    37  
    38  # Check invocation:
    39  me=${0##*/}
    40  img=$1
    41  if	[ $# -ne 1 -o ! -s "$img" ]
    42  then
    43  	echo "Usage: $me <kernel-image>" >&2
    44  	exit 2
    45  fi
    46  
    47  # Prepare temp files:
    48  tmp=$(mktemp /tmp/vmlinux-XXX)
    49  trap "rm -f $tmp" 0
    50  
    51  # That didn't work, so retry after decompression.
    52  try_decompress '\037\213\010' xy    gunzip
    53  try_decompress '\3757zXZ\000' abcde unxz
    54  try_decompress 'BZh'          xy    bunzip2
    55  try_decompress '\135\0\0\0'   xxx   unlzma
    56  try_decompress '\211\114\132' xy    'lzop -d'
    57  try_decompress '\002!L\030'   xxx   'lz4 -d'
    58  try_decompress '(\265/\375'   xxx   unzstd
    59  
    60  # Finally check for uncompressed images or objects:
    61  check_vmlinux $img
    62  
    63  # Bail out:
    64  echo "$me: Cannot find vmlinux." >&2