Python Library Documentation: module srvtab_edit

NAME
    srvtab_edit

FILE
    /home/users/mokrejs/proj/srvtab_edit.py

DESCRIPTION
    srvtab_edit.py is a Python module enabling you to manipulate keys
    in srvtab formatted file.  The aim is to have a tool to take individual
    keys out of a file and write them to separate file(s), or to write
    different combination of individual keys into a file.
    
    One can use then `ksrvutil -f srvtab.new change' to update host keys
    without the need to kerberos administrator. (You can of course forget
    this all, delete the srvtab and use `ksrvutil get' to download them
    from KDC or create them, if you know the administrators password.) ;)
    
    `ksrvutil -f srvtab.new change' will ensure you that the keys in *THAT*
    file match Kerberos KDC (matched before change and as the update went
    fine, the new key stored in that file must also match KDC). You can
    then use `cat(1)' to merge those files together to get a srvtab with
    more keys, or use this module in interactive session (see below).
    
    srvtab_edit.py does *NOT* implement delete function to delete
    keys, *BUT* you are expected to copy selected keys away into a new file.
    
    Although you need to be root to get read access on /etc/srvtab, you
    don't have to run this code as root.
    
    This program is available as is, without any warranty.
    Use it freely. ;)
    
    Martin Mokrejs <mmokrejs@natur.cuni.cz>
    http://www.natur.cuni.cz/~mmokrejs/afs
    21. 9. 2002 version 1.0
    
    
    Usage:
    
    python srvtab_edit.py
    
    The program will ask you for path to srvtab file, then show recognised
    keys in enumerated output.  Afterwards you can type in numbers
    (representing position of the key in original srvtab file) of keys to
    be copied to another file. If they are present, they will be written
    to such a new file. After creating the new srvtab file, you can reopen
    it in srvtab_edit.py *AND* `ksrvutil list' to see the result.
    Of course, `od -c srvtab' is also fine.
    
    
    On the other hand, you can use this module directly from interactive
    python session:
    
            shell$  start "python"
            >>> from srvtab_edit import *
            >>> tuple,count = readkeys("/etc/srvtab")
            >>> print "There are " + str(count) + " keys."
            >>> firstkey = instantiatekey(0,tuple)
            >>> secondkey = instantiatekey(1,tuple)
    
            ... and so on (do "ksrvutil -f /etc/srvtab list" before
                running python to see which keys you want to copy out)
    
            >>> print firstkey
            >>> print secondkey
    
            ... and so on
    
    [       ... you may open another srvtab and read from it other keys   ]
    [       >>> tuple,count = readkeys("./srvtab-2")                      ]
    [       >>> print "There are " + str(count) + " keys."                ]
    [       >>> tenthkey = instantiatekey(0,tuple)                        ]
    [       >>> eleventhkey = instantiatekey(11,tuple)                    ]
    
            >>> towrite = []
            >>> towrite.append(firstkey)
            >>> towrite.append(secondkey)
    
            ... and so on
    
    [       >>> owrite.append(eleventhkey)                                ]
    
    
            >>> print "Keys listed here will be copied to a new file: " +
                str(towrite)
    
            >>> writekeys("/etc/srvtab.new",towrite)
            Creating new file etc/srvtab.new
            Writing key ftp.pf-i400@NATUR.CUNI.CZ KVNO: 2.
            Writing key rcmd.pf-i400@NATUR.CUNI.CZ KVNO: 2.
            >>> CTRL-D

CLASSES
    Key
    
    class Key
     |  
     |  __init__(self, principal, host, realm, kvno, key)
     |  
     |  __repr__(self)
     |  
     |  write(self, file)

FUNCTIONS
    instantiatekey(keypos, tu)
        instantiatekey(keypos,tu) find the key in position `keypos'
        in the tuple `tu' and returns whole key as an instance consisting
        of self.principal, self.host, self.realm, self.kvno, self.key
        attributes.
    
    main()
    
    readkeys(file)
        readkeys(file) returns 2 values. First is a tuple
        containing keys, second is a number of keys read from a file
        We split srvtab using octal 0 as delimiter, which is missing
        after the key and next principal name. For example having
        4 keys in srvtab results in tuple of size 13 and fields are
        recognised as follows:
        
        principal = tuple[0]
        host = tuple[1]
        realm = tuple[2]
        key_plus_next_principal = tuple[3]
    
    writekeys(file, instlist)
        writekeys(file,instlist) writes all specified key
        instances to a *NEW* file.  If the file is already present,
        writekeys() will *NOT* touch it at all!

DATA
    IntType = <type 'int'>
    ListType = <type 'list'>
    StringType = <type 'string'>
    __file__ = './srvtab_edit.py'
    __name__ = 'srvtab_edit'