| 1 | n/a | # !/usr/bin/env python |
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| 2 | 1 | """Guess which db package to use to open a db file.""" |
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| 3 | n/a | |
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| 4 | 1 | import os |
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| 5 | 1 | import struct |
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| 6 | 1 | import sys |
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| 7 | n/a | |
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| 8 | 1 | try: |
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| 9 | 1 | import dbm |
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| 10 | 1 | _dbmerror = dbm.error |
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| 11 | 0 | except ImportError: |
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| 12 | 0 | dbm = None |
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| 13 | n/a | # just some sort of valid exception which might be raised in the |
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| 14 | n/a | # dbm test |
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| 15 | 0 | _dbmerror = IOError |
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| 16 | n/a | |
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| 17 | 1 | def whichdb(filename): |
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| 18 | n/a | """Guess which db package to use to open a db file. |
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| 19 | n/a | |
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| 20 | n/a | Return values: |
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| 21 | n/a | |
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| 22 | n/a | - None if the database file can't be read; |
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| 23 | n/a | - empty string if the file can be read but can't be recognized |
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| 24 | n/a | - the module name (e.g. "dbm" or "gdbm") if recognized. |
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| 25 | n/a | |
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| 26 | n/a | Importing the given module may still fail, and opening the |
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| 27 | n/a | database using that module may still fail. |
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| 28 | n/a | """ |
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| 29 | n/a | |
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| 30 | n/a | # Check for dbm first -- this has a .pag and a .dir file |
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| 31 | 96 | try: |
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| 32 | 96 | f = open(filename + os.extsep + "pag", "rb") |
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| 33 | 2 | f.close() |
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| 34 | n/a | # dbm linked with gdbm on OS/2 doesn't have .dir file |
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| 35 | 2 | if not (dbm.library == "GNU gdbm" and sys.platform == "os2emx"): |
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| 36 | 2 | f = open(filename + os.extsep + "dir", "rb") |
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| 37 | 2 | f.close() |
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| 38 | 2 | return "dbm" |
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| 39 | 94 | except IOError: |
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| 40 | n/a | # some dbm emulations based on Berkeley DB generate a .db file |
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| 41 | n/a | # some do not, but they should be caught by the dbhash checks |
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| 42 | 94 | try: |
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| 43 | 94 | f = open(filename + os.extsep + "db", "rb") |
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| 44 | 0 | f.close() |
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| 45 | n/a | # guarantee we can actually open the file using dbm |
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| 46 | n/a | # kind of overkill, but since we are dealing with emulations |
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| 47 | n/a | # it seems like a prudent step |
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| 48 | 0 | if dbm is not None: |
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| 49 | 0 | d = dbm.open(filename) |
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| 50 | 0 | d.close() |
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| 51 | 0 | return "dbm" |
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| 52 | 94 | except (IOError, _dbmerror): |
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| 53 | 94 | pass |
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| 54 | n/a | |
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| 55 | n/a | # Check for dumbdbm next -- this has a .dir and a .dat file |
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| 56 | 94 | try: |
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| 57 | n/a | # First check for presence of files |
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| 58 | 94 | os.stat(filename + os.extsep + "dat") |
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| 59 | 2 | size = os.stat(filename + os.extsep + "dir").st_size |
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| 60 | n/a | # dumbdbm files with no keys are empty |
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| 61 | 2 | if size == 0: |
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| 62 | 1 | return "dumbdbm" |
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| 63 | 1 | f = open(filename + os.extsep + "dir", "rb") |
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| 64 | 1 | try: |
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| 65 | 1 | if f.read(1) in ("'", '"'): |
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| 66 | 1 | return "dumbdbm" |
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| 67 | n/a | finally: |
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| 68 | 1 | f.close() |
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| 69 | 92 | except (OSError, IOError): |
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| 70 | 92 | pass |
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| 71 | n/a | |
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| 72 | n/a | # See if the file exists, return None if not |
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| 73 | 92 | try: |
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| 74 | 92 | f = open(filename, "rb") |
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| 75 | 85 | except IOError: |
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| 76 | 85 | return None |
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| 77 | n/a | |
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| 78 | n/a | # Read the start of the file -- the magic number |
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| 79 | 7 | s16 = f.read(16) |
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| 80 | 7 | f.close() |
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| 81 | 7 | s = s16[0:4] |
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| 82 | n/a | |
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| 83 | n/a | # Return "" if not at least 4 bytes |
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| 84 | 7 | if len(s) != 4: |
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| 85 | 0 | return "" |
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| 86 | n/a | |
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| 87 | n/a | # Convert to 4-byte int in native byte order -- return "" if impossible |
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| 88 | 7 | try: |
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| 89 | 7 | (magic,) = struct.unpack("=l", s) |
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| 90 | 0 | except struct.error: |
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| 91 | 0 | return "" |
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| 92 | n/a | |
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| 93 | n/a | # Check for GNU dbm |
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| 94 | 7 | if magic == 0x13579ace: |
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| 95 | 2 | return "gdbm" |
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| 96 | n/a | |
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| 97 | n/a | # Check for old Berkeley db hash file format v2 |
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| 98 | 5 | if magic in (0x00061561, 0x61150600): |
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| 99 | 0 | return "bsddb185" |
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| 100 | n/a | |
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| 101 | n/a | # Later versions of Berkeley db hash file have a 12-byte pad in |
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| 102 | n/a | # front of the file type |
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| 103 | 5 | try: |
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| 104 | 5 | (magic,) = struct.unpack("=l", s16[-4:]) |
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| 105 | 0 | except struct.error: |
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| 106 | 0 | return "" |
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| 107 | n/a | |
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| 108 | n/a | # Check for BSD hash |
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| 109 | 5 | if magic in (0x00061561, 0x61150600): |
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| 110 | 5 | return "dbhash" |
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| 111 | n/a | |
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| 112 | n/a | # Unknown |
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| 113 | 0 | return "" |
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| 114 | n/a | |
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| 115 | 1 | if __name__ == "__main__": |
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| 116 | 0 | for filename in sys.argv[1:]: |
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| 117 | 0 | print whichdb(filename) or "UNKNOWN", filename |
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