#!python3

"""
Command line tool to get program database (PDB) debug symbols file URL from windows server.
With options to download the PDB file directly.

Credits to **Barakat@github** for the original script, though it didn't work without modifications:
    https://gist.github.com/Barakat/e20ec993748c6ab382d727f08eaa523e
I fixed the GUID calculation which were ignoring Signature_Data5 and Signature_Data6 thus not creating a complete GUID.
Also I added the ability to download the file directly and a simple command line functionality.

example:
```console
$ python pdburl.py -d kernel32.dll

PDB symbols file for kernel32.dll:
        https://msdl.microsoft.com/download/symbols/kernel32.pdb/5A77DE8CE8D58731F0EA38F1C92F48D81/kernel32.pdb
Downloading...
        Downloaded: https://msdl.microsoft.com/download/symbols/kernel32.pdb/5A77DE8CE8D58731F0EA38F1C92F48D81/kernel32.pdb
        To:         kernel32.pdb
```
"""

import os
import argparse
import pefile
import urllib.request


SYMBOLS_SERVER = 'https://msdl.microsoft.com/download/symbols'


def get_pdb_symbol_url(binary_file_path: str):
    """
    Gets the PDB debug symbols file of the given binary file from windows server.
    Arguments:
        binary_file_path: Binary file to get PDB to.
    """
    pe = pefile.PE(binary_file_path, fast_load=True)
    pe.parse_data_directories()

    for directory in pe.DIRECTORY_ENTRY_DEBUG:
        debug_entry = directory.entry
        if hasattr(debug_entry, 'PdbFileName'):
            pdb_file = debug_entry.PdbFileName[:-1].decode('ascii')
            guid = ''
            guid += f'{debug_entry.Signature_Data1:08x}'
            guid += f'{debug_entry.Signature_Data2:04x}'
            guid += f'{debug_entry.Signature_Data3:04x}'
            guid += f'{debug_entry.Signature_Data4:02x}'
            guid += f'{debug_entry.Signature_Data5:02x}'
            guid += f'{int.from_bytes(debug_entry.Signature_Data6, byteorder='big'):012x}'
            guid = guid.upper()
            url = f'{SYMBOLS_SERVER}/{pdb_file}/{guid}{debug_entry.Age:x}/{pdb_file}'
            return url
     
    return None
    
   
def downlod_pdb_symbol_file(binary_file_path: str):
    """
    Downloads the PDB debug symbols file of the given binary file from windows server.
    Arguments:
        binary_file_path: Binary file to get PDB to.
    """
    # get url
    url = get_pdb_symbol_url(binary_file_path)
    print(f"PDB symbols file for {os.path.split(binary_file_path)[1]}:")
    print(f"\t{url}")
    
    # calculate output file path
    output_dir = os.path.split(binary_file_path)[0]
    output_file_name = os.path.split(url)[1]
    output_file_path = os.path.join(output_dir, output_file_name)

    # download
    print(f"Downloading...")
    urllib.request.urlretrieve(url, output_file_path)
    print(f"\tDownloaded: {url}")
    print(f"\tTo:         {output_file_path}")


def main():
    """
    Gets debug symbols url of a windows binary.
    """

    # parse arguments
    parser = argparse.ArgumentParser(description='Command line tool to get PDB symbols file URL from windows server for a windows binary file with the ability to download it.')
    parser.add_argument('input', type=str, help='Input binary file.')
    parser.add_argument('-d', "--download", action='store_true', help='Download the PDB symbols file instead of just outputing the URL.')
    args = parser.parse_args()
    
    # handle based on the download switch
    if args.download:
        downlod_pdb_symbol_file(args.input)
    else:
        # just print the URL
        url = get_pdb_symbol_url(args.input)
        print(f"PDB symbols file for {os.path.split(args.input)[1]}:")
        print(f"\t{url}")
        

if __name__ == '__main__':
    main()