cryptonas-archive/v0.3.4.4/src/cryptobox/core/tools.py

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#
# 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
#
"""Some useful functions for the CryptoBox.
"""
__revision__ = "$Id"
import logging
import os
import re
LOGGER = logging.getLogger("CryptoBox")
def get_available_partitions():
"retrieve a list of all available containers"
ret_list = []
try:
## the following reads all lines of /proc/partitions and adds the mentioned devices
fpart = open("/proc/partitions", "r")
try:
line = fpart.readline()
while line:
p_details = line.split()
if (len(p_details) == 4):
## the following code prevents double entries like /dev/hda and /dev/hda1
(p_major, p_minor, p_size, p_device) = p_details
## ignore lines with: invalid minor/major or extend partitions (size=1)
if re.search('^[0-9]*$', p_major) and \
re.search('^[0-9]*$', p_minor) and (p_size != "1"):
## for some parent devices we have to remove a 'p' (partition)
## an example are partitionable mdadm raid devices (e.g. md1p1)
p_parent = re.sub('p?[1-9]?[0-9]$', '', p_device)
if p_parent == p_device:
if [e for e in ret_list
if re.search('^' + p_parent + 'p?[1-9]?[0-9]$', e)]:
## major partition - its children are already in the list
pass
else:
## major partition - but there are no children for now
ret_list.append(p_device)
else:
## minor partition - remove parent if necessary
if p_parent in ret_list:
ret_list.remove(p_parent)
ret_list.append(p_device)
line = fpart.readline()
finally:
fpart.close()
return [ get_absolute_devicename(e) for e in ret_list ]
except IOError:
LOGGER.warning("Could not read /proc/partitions")
return []
def get_absolute_devicename(shortname):
""" returns the absolute file name of a device (e.g.: "hda1" -> "/dev/hda1")
this does also work for device mapper devices
if the result is non-unique, one arbitrary value is returned
"""
if re.search('^/', shortname):
return shortname
default = os.path.join("/dev", shortname)
if os.path.exists(default):
return default
result = find_major_minor_of_device(shortname)
## if no valid major/minor was found -> exit
if not result:
return default
(major, minor) = result
## for device-mapper devices (major == 254) ...
if major == 254:
result = find_major_minor_device("/dev/mapper", major, minor)
if result:
return result[0]
## now check all files in /dev
result = find_major_minor_device("/dev", major, minor)
if result:
return result[0]
return default
def find_major_minor_of_device(device):
"""Return the major/minor numbers of a block device.
"""
if re.match("/", device) or \
not os.path.exists(os.path.join(os.path.sep, "sys", "block", device)):
## maybe it is an absolute device name
if not os.path.exists(device):
return None
## okay - it seems to to a device node
rdev = os.stat(device).st_rdev
return (os.major(rdev), os.minor(rdev))
blockdev_info_file = os.path.join(os.path.join(
os.path.sep,"sys","block", device), "dev")
try:
f_blockdev_info = open(blockdev_info_file, "r")
blockdev_info = f_blockdev_info.read()
f_blockdev_info.close()
(str_major, str_minor) = blockdev_info.split(":")
## numeric conversion
try:
major = int(str_major)
minor = int(str_minor)
return (major, minor)
except ValueError:
## unknown device numbers -> stop guessing
return None
except IOError:
pass
return None
def find_major_minor_device(dirpath, major, minor):
"""Returns the names of devices with the specified major and minor number.
"""
collected = []
try:
subdirs = [os.path.join(dirpath, e) for e in os.listdir(dirpath)
if (not os.path.islink(os.path.join(dirpath, e))) and \
os.path.isdir(os.path.join(dirpath, e))]
## do a recursive call to parse the directory tree
for dirs in subdirs:
collected.extend(find_major_minor_device(dirs, major, minor))
## filter all device inodes in this directory
collected.extend([os.path.realpath(os.path.join(dirpath, e))
for e in os.listdir(dirpath)
if (os.major(os.stat(os.path.join(dirpath, e)).st_rdev) == major) \
and (os.minor(os.stat(os.path.join(dirpath, e)).st_rdev) == minor)])
## remove double entries
result = []
for item in collected:
if item not in result:
result.append(item)
return result
except OSError:
return []
def get_parent_blockdevices():
"""Return a list of all block devices that contain other devices.
"""
devs = []
for line in file("/proc/partitions"):
p_details = line.split()
## we expect four values - otherwise continue with next iteration
if len(p_details) != 4:
continue
(p_major, p_minor, p_size, p_device) = p_details
## we expect numeric values in the first two columns
if re.search(r'\D', p_major) or re.search(r'\D', p_minor):
continue
## now let us check, if it is a (parent) block device or a partition
if not os.path.isdir(os.path.join(os.path.sep, "sys", "block", p_device)):
continue
devs.append(p_device)
return [ get_absolute_devicename(e) for e in devs ]
def is_part_of_blockdevice(parent, subdevice):
"""Check if the given block device is a parent of 'subdevice'.
e.g. for checking if a partition belongs to a block device
"""
try:
(par_major, par_minor) = find_major_minor_of_device(parent)
(sub_major, sub_minor) = find_major_minor_of_device(subdevice)
except TypeError:
## at least one of these devices did not return a valid major/minor combination
return False
## search the entry below '/sys/block' belonging to the parent
root = os.path.join(os.path.sep, 'sys', 'block')
for bldev in os.listdir(root):
blpath = os.path.join(root, bldev, 'dev')
if os.access(blpath, os.R_OK):
try:
if (str(par_major), str(par_minor)) == tuple([e
for e in file(blpath)][0].strip().split(":",1)):
parent_path = os.path.join(root, bldev)
break
except (IndexError, OSError):
pass
else:
## no block device with this major/minor combination found below '/sys/block'
return False
for subbldev in os.listdir(parent_path):
subblpath = os.path.join(parent_path, subbldev, "dev")
if os.access(subblpath, os.R_OK):
try:
if (str(sub_major), str(sub_minor)) == tuple([e
for e in file(subblpath)][0].strip().split(":",1)):
## the name of the subdevice node is not important - we found it!
return True
except (IndexError, OSError):
pass
return False
def get_blockdevice_size(device):
"""Return the size of a blockdevice in megabyte.
"""
if not device:
return -1
try:
rdev = os.stat(device).st_rdev
except OSError:
return -1
minor = os.minor(rdev)
major = os.major(rdev)
for line in file("/proc/partitions"):
try:
elements = line.split()
if len(elements) != 4:
continue
if (int(elements[0]) == major) and (int(elements[1]) == minor):
return int(elements[2])/1024
except ValueError:
pass
return -1
def get_blockdevice_size_humanly(device):
"""Return a human readable size of a blockdevice.
"""
size = get_blockdevice_size(device)
if size > 5120:
return "%dGB" % int(size/1024)
else:
return "%dMB" % size