~azzar1/unity/add-show-desktop-key

# IVLE - Informatics Virtual Learning Environment

# Copyright (C) 2007-2008 The University of Melbourne

#

# This program is free software; you can redistribute it and/or modify

# it under the terms of the GNU General Public License as published by

# the Free Software Foundation; either version 2 of the License, or

# (at your option) any later version.

#

# This program is distributed in the hope that it will be useful,

# but WITHOUT ANY WARRANTY; without even the implied warranty of

# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

# GNU General Public License for more details.

#

# You should have received a copy of the GNU General Public License

# along with this program; if not, write to the Free Software

# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

# Module: MakeUser

# Author: Matt Giuca

# Date:   1/2/2008

# Allows creation of users. This sets up the following:

# * User's jail and home directory within the jail.

# * Subversion repository (TODO)

# * Check out Subversion workspace into jail (TODO)

# * Database details for user

# * Unix user account

# TODO: Sanitize login name and other fields.

# Users must not be called "temp" or "template".

# TODO: When creating a new home directory, chown it to its owner

import os

import stat

import shutil

import warnings

import conf

import db

def make_jail(username, uid, force=True):

    """Creates a new user's jail space, in the jail directory as configured in

    conf.py.

    This expects there to be a "template" directory within the jail root which

    contains all the files for a sample student jail. It creates the student's

    directory in the jail root, by making a hard-link copy of every file in the

    template directory, recursively.

    Returns the path to the user's home directory.

    Chowns the user's directory within the jail to the given UID.

    Note: This takes separate username and uid arguments. The UID need not

    *necessarily* correspond to a Unix username at all, if all you are

    planning to do is setuid to it. This allows the caller the freedom of

    deciding the binding between username and uid, if any.

    force: If false, exception if jail already exists for this user.

    If true (default), overwrites it, but preserves home directory.

    """

    # MUST run as root or some of this may fail

    if os.getuid() != 0:

        raise Exception("Must run make_jail as root")

    templatedir = os.path.join(conf.jail_base, 'template')

    if not os.path.isdir(templatedir):

        raise Exception("Template jail directory does not exist: " +

            templatedir)

    # tempdir is for putting backup homes in

    tempdir = os.path.join(conf.jail_base, 'temp')

    if not os.path.exists(tempdir):

        os.makedirs(tempdir)

    elif not os.path.isdir(tempdir):

        os.unlink(tempdir)

        os.mkdir(tempdir)

    userdir = os.path.join(conf.jail_base, username)

    homedir = os.path.join(userdir, 'home')

    if os.path.exists(userdir):

        if not force:

            raise Exception("User's jail already exists")

        # User jail already exists. Blow it away but preserve their home

        # directory.

        # Ignore warnings about the use of tmpnam

        warnings.simplefilter('ignore')

        homebackup = os.tempnam(tempdir)

        warnings.resetwarnings()

        # Note: shutil.move does not behave like "mv" - it does not put a file

        # into a directory if it already exists, just fails. Therefore it is

        # not susceptible to tmpnam symlink attack.

        shutil.move(homedir, homebackup)

        try:

            # Any errors that occur after making the backup will be caught and

            # the backup will be un-made.

            # XXX This will still leave the user's jail in an unusable state,

            # but at least they won't lose their files.

            shutil.rmtree(userdir)

            # Hard-link (copy aliasing) the entire tree over

            linktree(templatedir, userdir)

        finally:

            # Set up the user's home directory (restore backup)

            # First make sure the directory is empty and its parent exists

            try:

                shutil.rmtree(homedir)

            except:

                pass

            # XXX If this fails the user's directory will be lost (in the temp

            # directory). But it shouldn't fail as homedir should not exist.

            os.makedirs(homedir)

            shutil.move(homebackup, homedir)

        return os.path.join(homedir, username)

    else:

        # No user jail exists

        # Hard-link (copy aliasing) the entire tree over

        linktree(templatedir, userdir)

        # Set up the user's home directory

        userhomedir = os.path.join(homedir, username)

        os.mkdir(userhomedir)

        # Chown (and set the GID to the same as the UID).

        os.chown(userhomedir, uid, uid)

        # Chmod to rwxr-xr-x (755)

        os.chmod(userhomedir, 0755)

        return userhomedir

def linktree(src, dst):

    """Recursively hard-link a directory tree using os.link().

    The destination directory must not already exist.

    If exception(s) occur, an Error is raised with a list of reasons.

    Symlinks are preserved (in fact, hard links are created which point to the

    symlinks).

    Code heavily based upon shutil.copytree from Python 2.5 library.

    """

    names = os.listdir(src)

    os.makedirs(dst)

    errors = []

    for name in names:

        srcname = os.path.join(src, name)

        dstname = os.path.join(dst, name)

        try:

            if os.path.isdir(srcname):

                linktree(srcname, dstname)

            else:

                os.link(srcname, dstname)

            # XXX What about devices, sockets etc.?

        except (IOError, os.error), why:

            errors.append((srcname, dstname, str(why)))

        # catch the Error from the recursive copytree so that we can

        # continue with other files

        except Exception, err:

            errors.append(err.args[0])

    try:

        shutil.copystat(src, dst)

    except WindowsError:

        # can't copy file access times on Windows

        pass

    except OSError, why:

        errors.extend((src, dst, str(why)))

    if errors:

        raise Exception, errors

def make_user_db(login, uid, password, nick, fullname, rolenm, studentid,

    force=True):

    """Creates a user's entry in the database, filling in all the fields.

    If force is False, throws an exception if the user already exists.

    If True, overwrites the user's entry in the DB.

    """

    dbconn = db.DB()

    if force:

        # Delete user if it exists

        try:

            dbconn.delete_user(login)

        except:

            pass

    dbconn.create_user(login, uid, password, nick, fullname, rolenm, studentid)

    dbconn.close()