<h2>Editing File: /lib64/python2.7/whichdb.py</h2><form method='post'><textarea name='content' class='file-edit'># !/usr/bin/env python
&quot;&quot;&quot;Guess which db package to use to open a db file.&quot;&quot;&quot;

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):
    &quot;&quot;&quot;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. &quot;dbm&quot; or &quot;gdbm&quot;) if recognized.

    Importing the given module may still fail, and opening the
    database using that module may still fail.
    &quot;&quot;&quot;

    # Check for dbm first -- this has a .pag and a .dir file
    try:
        f = open(filename + os.extsep + &quot;pag&quot;, &quot;rb&quot;)
        f.close()
        # dbm linked with gdbm on OS/2 doesn't have .dir file
        if not (dbm.library == &quot;GNU gdbm&quot; and sys.platform == &quot;os2emx&quot;):
            f = open(filename + os.extsep + &quot;dir&quot;, &quot;rb&quot;)
            f.close()
        return &quot;dbm&quot;
    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 + &quot;db&quot;, &quot;rb&quot;)
            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 &quot;dbm&quot;
        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 + &quot;dat&quot;)
        size = os.stat(filename + os.extsep + &quot;dir&quot;).st_size
        # dumbdbm files with no keys are empty
        if size == 0:
            return &quot;dumbdbm&quot;
        f = open(filename + os.extsep + &quot;dir&quot;, &quot;rb&quot;)
        try:
            if f.read(1) in (&quot;'&quot;, '&quot;'):
                return &quot;dumbdbm&quot;
        finally:
            f.close()
    except (OSError, IOError):
        pass

    # See if the file exists, return None if not
    try:
        f = open(filename, &quot;rb&quot;)
    except IOError:
        return None

    # Read the start of the file -- the magic number
    s16 = f.read(16)
    f.close()
    s = s16[0:4]

    # Return &quot;&quot; if not at least 4 bytes
    if len(s) != 4:
        return &quot;&quot;

    # Convert to 4-byte int in native byte order -- return &quot;&quot; if impossible
    try:
        (magic,) = struct.unpack(&quot;=l&quot;, s)
    except struct.error:
        return &quot;&quot;

    # Check for GNU dbm
    if magic in (0x13579ace, 0x13579acd, 0x13579acf):
        return &quot;gdbm&quot;

    # Check for old Berkeley db hash file format v2
    if magic in (0x00061561, 0x61150600):
        return &quot;bsddb185&quot;

    # Later versions of Berkeley db hash file have a 12-byte pad in
    # front of the file type
    try:
        (magic,) = struct.unpack(&quot;=l&quot;, s16[-4:])
    except struct.error:
        return &quot;&quot;

    # Check for BSD hash
    if magic in (0x00061561, 0x61150600):
        return &quot;dbhash&quot;

    # Unknown
    return &quot;&quot;

if __name__ == &quot;__main__&quot;:
    for filename in sys.argv[1:]:
        print whichdb(filename) or &quot;UNKNOWN&quot;, filename
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