# this module is an OS/2 oriented replacement for the pwd standard

# extension module.

# written by Andrew MacIntyre, April 2001.

# updated July 2003, adding field accessor support

# note that this implementation checks whether ":" or ";" as used as

# the field separator character.  Path conversions are are applied when

# the database uses ":" as the field separator character.

"""Replacement for pwd standard extension module, intended for use on

OS/2 and similar systems which don't normally have an /etc/passwd file.

The standard Unix password database is an ASCII text file with 7 fields

per record (line), separated by a colon:

  - user name (string)

  - password (encrypted string, or "*" or "")

  - user id (integer)

  - group id (integer)

  - description (usually user's name)

  - home directory (path to user's home directory)

  - shell (path to the user's login shell)

(see the section 8.1 of the Python Library Reference)

This implementation differs from the standard Unix implementation by

allowing use of the platform's native path separator character - ';' on OS/2,

DOS and MS-Windows - as the field separator in addition to the Unix

standard ":".  Additionally, when ":" is the separator path conversions

are applied to deal with any munging of the drive letter reference.

The module looks for the password database at the following locations

(in order first to last):

  - ${ETC_PASSWD}             (or %ETC_PASSWD%)

  - ${ETC}/passwd             (or %ETC%/passwd)

  - ${PYTHONHOME}/Etc/passwd  (or %PYTHONHOME%/Etc/passwd)

Classes

-------

None

Functions

---------

getpwuid(uid) -  return the record for user-id uid as a 7-tuple

getpwnam(name) - return the record for user 'name' as a 7-tuple

getpwall() -     return a list of 7-tuples, each tuple being one record

                 (NOTE: the order is arbitrary)

Attributes

----------

passwd_file -    the path of the password database file

"""

import os

# try and find the passwd file

__passwd_path = []

if os.environ.has_key('ETC_PASSWD'):

    __passwd_path.append(os.environ['ETC_PASSWD'])

if os.environ.has_key('ETC'):

    __passwd_path.append('%s/passwd' % os.environ['ETC'])

if os.environ.has_key('PYTHONHOME'):

    __passwd_path.append('%s/Etc/passwd' % os.environ['PYTHONHOME'])

passwd_file = None

for __i in __passwd_path:

    try:

        __f = open(__i, 'r')

        __f.close()

        passwd_file = __i

        break

    except:

        pass

# path conversion handlers

def __nullpathconv(path):

    return path.replace(os.altsep, os.sep)

def __unixpathconv(path):

    # two known drive letter variations: "x;" and "$x"

    if path[0] == '$':

        conv = path[1] + ':' + path[2:]

    elif path[1] == ';':

        conv = path[0] + ':' + path[2:]

    else:

        conv = path

    return conv.replace(os.altsep, os.sep)

# decide what field separator we can try to use - Unix standard, with

# the platform's path separator as an option.  No special field conversion

# handler is required when using the platform's path separator as field

# separator, but are required for the home directory and shell fields when

# using the standard Unix (":") field separator.

__field_sep = {':': __unixpathconv}

if os.pathsep:

    if os.pathsep != ':':

        __field_sep[os.pathsep] = __nullpathconv

# helper routine to identify which separator character is in use

def __get_field_sep(record):

    fs = None

    for c in __field_sep.keys():

        # there should be 6 delimiter characters (for 7 fields)

        if record.count(c) == 6:

            fs = c

            break

    if fs:

        return fs

    else:

        raise KeyError, '>> passwd database fields not delimited <<'

# class to match the new record field name accessors.

# the resulting object is intended to behave like a read-only tuple,

# with each member also accessible by a field name.

class Passwd:

    def __init__(self, name, passwd, uid, gid, gecos, dir, shell):

        self.__dict__['pw_name'] = name

        self.__dict__['pw_passwd'] = passwd

        self.__dict__['pw_uid'] = uid

        self.__dict__['pw_gid'] = gid

        self.__dict__['pw_gecos'] = gecos

        self.__dict__['pw_dir'] = dir

        self.__dict__['pw_shell'] = shell

        self.__dict__['_record'] = (self.pw_name, self.pw_passwd,

                                    self.pw_uid, self.pw_gid,

                                    self.pw_gecos, self.pw_dir,

                                    self.pw_shell)

    def __len__(self):

        return 7

    def __getitem__(self, key):

        return self._record[key]

    def __setattr__(self, name, value):

        raise AttributeError('attribute read-only: %s' % name)

    def __repr__(self):

        return str(self._record)

    def __cmp__(self, other):

        this = str(self._record)

        if this == other:

            return 0

        elif this < other:

            return -1

        else:

            return 1

# read the whole file, parsing each entry into tuple form

# with dictionaries to speed recall by UID or passwd name

def __read_passwd_file():

    if passwd_file:

        passwd = open(passwd_file, 'r')

    else:

        raise KeyError, '>> no password database <<'

    uidx = {}

    namx = {}

    sep = None

    while 1:

        entry = passwd.readline().strip()

        if len(entry) > 6:

            if sep is None:

                sep = __get_field_sep(entry)

            fields = entry.split(sep)

            for i in (2, 3):

                fields[i] = int(fields[i])

            for i in (5, 6):

                fields[i] = __field_sep[sep](fields[i])

            record = Passwd(*fields)

            if not uidx.has_key(fields[2]):

                uidx[fields[2]] = record

            if not namx.has_key(fields[0]):

                namx[fields[0]] = record

        elif len(entry) > 0:

            pass                         # skip empty or malformed records

        else:

            break

    passwd.close()

    if len(uidx) == 0:

        raise KeyError

    return (uidx, namx)

# return the passwd database entry by UID

def getpwuid(uid):

    u, n = __read_passwd_file()

    return u[uid]

# return the passwd database entry by passwd name

def getpwnam(name):

    u, n = __read_passwd_file()

    return n[name]

# return all the passwd database entries

def getpwall():

    u, n = __read_passwd_file()

    return n.values()

# test harness

if __name__ == '__main__':

    getpwall()