JezK
Edit File: whichdb.py
# !/usr/bin/env python """Guess which db package to use to open a db file.""" import os import struct import sys try: import dbm _dbmerror = dbm.error except ImportError: dbm = None # just some sort of valid exception which might be raised in the # dbm test _dbmerror = IOError def whichdb(filename): """Guess which db package to use to open a db file. Return values: - None if the database file can't be read; - empty string if the file can be read but can't be recognized - the module name (e.g. "dbm" or "gdbm") if recognized. Importing the given module may still fail, and opening the database using that module may still fail. """ # Check for dbm first -- this has a .pag and a .dir file try: f = open(filename + os.extsep + "pag", "rb") f.close() # dbm linked with gdbm on OS/2 doesn't have .dir file if not (dbm.library == "GNU gdbm" and sys.platform == "os2emx"): f = open(filename + os.extsep + "dir", "rb") f.close() return "dbm" except IOError: # some dbm emulations based on Berkeley DB generate a .db file # some do not, but they should be caught by the dbhash checks try: f = open(filename + os.extsep + "db", "rb") f.close() # guarantee we can actually open the file using dbm # kind of overkill, but since we are dealing with emulations # it seems like a prudent step if dbm is not None: d = dbm.open(filename) d.close() return "dbm" except (IOError, _dbmerror): pass # Check for dumbdbm next -- this has a .dir and a .dat file try: # First check for presence of files os.stat(filename + os.extsep + "dat") size = os.stat(filename + os.extsep + "dir").st_size # dumbdbm files with no keys are empty if size == 0: return "dumbdbm" f = open(filename + os.extsep + "dir", "rb") try: if f.read(1) in ("'", '"'): return "dumbdbm" finally: f.close() except (OSError, IOError): pass # See if the file exists, return None if not try: f = open(filename, "rb") except IOError: return None # Read the start of the file -- the magic number s16 = f.read(16) f.close() s = s16[0:4] # Return "" if not at least 4 bytes if len(s) != 4: return "" # Convert to 4-byte int in native byte order -- return "" if impossible try: (magic,) = struct.unpack("=l", s) except struct.error: return "" # Check for GNU dbm if magic in (0x13579ace, 0x13579acd, 0x13579acf): return "gdbm" # Check for old Berkeley db hash file format v2 if magic in (0x00061561, 0x61150600): return "bsddb185" # Later versions of Berkeley db hash file have a 12-byte pad in # front of the file type try: (magic,) = struct.unpack("=l", s16[-4:]) except struct.error: return "" # Check for BSD hash if magic in (0x00061561, 0x61150600): return "dbhash" # Unknown return "" if __name__ == "__main__": for filename in sys.argv[1:]: print whichdb(filename) or "UNKNOWN", filename