/usr/lib/python2.7/whichdb.py is in libpython2.7-stdlib 2.7.6-8ubuntu0.5.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 | # !/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
|