#
# Copyright 2006 sense.lab e.V.
# 
# This file is part of the CryptoBox.
#
# The CryptoBox 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.
# 
# The CryptoBox 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 the CryptoBox; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#

"""
this module contains some useful tools to be used during the tests

just inherit one of its classes and add some test functions
"""

__revision__ = "$Id$"



import os
import subprocess

def find_test_device(candidate):
    """Check for a valid test device - the data will get lost ...

    the result is the parent blockdevice (containing the partition table)
    and the single partition
    """
    dev = candidate
    if os.path.exists("/dev/%s" % dev) \
            and os.access("/dev/%s" % dev, os.W_OK):
        try:
            ## try if it is a symlink
            return os.readlink("/dev/%s" % dev)
        except OSError:
            ## not a symlink (usual)
            return "/dev/%s" % dev
    else:
        raise Exception, "no valid device for testing found"
    

def is_config_partition(device):
    """Check if the device is a configuration partition.
    """
    proc = subprocess.Popen(
        shell = False,
        stdout = subprocess.PIPE,
        stderr = subprocess.PIPE,
        args = [ '/sbin/e2label',
            device ])
    (stdout, stderr) = proc.communicate()
    return stdout.strip() == "cbox_config"


def umount(device):
    """Umount the specified device if possible - ignore errors
    """
    proc = subprocess.Popen(
        shell = False,
        stdout = subprocess.PIPE,
        stderr = subprocess.PIPE,
        args = [ '/bin/umount', '-d', device ])
    proc.wait()


def prepare_partition(blockdevice):
    """Prepare the expected partition in the device (destroy all data)
    
    Check if 'device' is a vfat partition - if not, then
    partition 'blockdevice' and format 'device' as vfat
    """
    if (get_fs_type(blockdevice + "1") == "vfat") \
            and (get_fs_type(blockdevice + "2") == "ext3") \
            and (get_fs_type(blockdevice + "3") is None) \
            and (get_fs_type(blockdevice + "5") is None):
        ## everything is fine
        return
    else:
        ## repartitioning
        proc = subprocess.Popen(
            shell = False,
            stdin = subprocess.PIPE,
            stdout = subprocess.PIPE,
            stderr = subprocess.PIPE,
            args = [ '/sbin/sfdisk', blockdevice ])
        # create two partitions (20MB fat, 20MB ext)
        proc.stdin.write(",10,0xC\n,10,L\n")
        (output, error) = proc.communicate()
        if proc.returncode != 0:
            raise Exception, "could not partition the device (%s): %s" \
                    % (blockdevice, output.strip())
        ## formatting
        format_device(blockdevice + "1", "vfat")
        format_device(blockdevice + "2", "ext3")


def get_fs_type(device):
    proc = subprocess.Popen(
        shell = False,
        stdout = subprocess.PIPE,
        stderr = subprocess.PIPE,
        args = [ '/sbin/blkid',
            '-c', os.path.devnull,
            '-w', os.path.devnull,
            '-o', 'value',
            '-s', 'TYPE',
            device])
    (output, error) = proc.communicate()
    if (proc.returncode == 0) and output.strip():
        ## everything is fine
        return output.strip()
    else:
        return None


def format_device(device, fs_type="vfat"):
        proc = subprocess.Popen(
            shell = False,
            stdout = subprocess.PIPE,
            stderr = subprocess.PIPE,
            args = [ '/sbin/mkfs',
                '-t', fs_type,
                device ])
        (output, error) = proc.communicate()
        if proc.returncode != 0:
            raise OSError, "could not format the device (%s): %s" \
                    % (device, output.strip())