libc changer

#!/bin/bash
#
# for ctf
# 配られたlibcが手元に無くても無理やりバイナリを動かすことが出来るようにパッチを行う
#
#
if [ $# -eq 0 ]; then
    echo "usage: $0 [ubuntu-version] [glibc-version] elf-file"
    exit 1
fi
#get debug symbol and interpreter
sudo docker pull ubuntu:$1
sudo docker run --name tmp$1 -i -t ubuntu:$1 bash -c "apt update && apt install libc6-dbg"
sudo docker cp tmp$1:/lib/x86_64-linux-gnu/ld-$2.so .
sudo docker cp tmp$1:/lib/x86_64-linux-gnu/libc-$2.so "libc.so.6"
mkdir ".debug"
sudo docker cp tmp$1:/usr/lib/debug/lib/x86_64-linux-gnu/libc-$2.so ".debug/libc.so.6"
mkdir -p .debug/lib/x86_64-linux-gnu/
sudo docker cp tmp$1:/usr/lib/debug/lib/x86_64-linux-gnu/ld-$2.so ".debug/ld-$2.so"
sudo docker rm tmp$1
#patchelf
patchelf --set-interpreter `pwd`/ld-$2.so $3
patchelf --replace-needed  libc.so.6 "`pwd`/libc.so.6" $3
patchelf  --set-rpath `pwd` $3

loadsym.py

import gdb
import subprocess

class loadsym(gdb.Command):
    """
    load symbol file to glibc
    Usage: loadsym {symbol file}
    Example:
        (gdb) loadsym '/path/to/usr/lib/debug/lib/x86_64-linux-gnu/libc-2.27.so'
    """

    def __init__(self):
        '''
        register command in constructer function
        '''

        super(self.__class__, self).__init__("loadsym", gdb.COMMAND_USER)

    def invoke(self, args, from_tty):
        '''
        in invoke method, we add command's features
        '''

        # using string_to_argv to convert args to list
        argv = gdb.string_to_argv(args)
        #if len(argv) != 1:
        #    raise gdb.GdbError(
        #        'Fail to execute command, use "help loadsym" for help')
        print('[*] symbol file path: {}'.format(".debug/libc.so.6"))

        # traverse objfiles to find libc
        #gdb.execute("set debug-file-directory "+subprocess.check_output(["pwd"]).decode()+"/.debug")
        for i in gdb.objfiles():
            if 'libc' in i.filename:
                self.add_debug_file(i, ".debug/libc.so.6")
                return
        print('[-] fail to find libc!')

    def add_debug_file(self, objfile, debugfile_path):
        '''
        add debug file and check debug file's status
        '''

        objfile.add_separate_debug_file(debugfile_path)
        # check symbol file is loading
        if gdb.lookup_symbol('main_arena') == None:
            print('[-] load debug file fail!')
            return False
        else:
            print('[+] load debug file success!')
            return True


if __name__ == "__main__":
    loadsym()