cryptonas-branches/pythonrewrite/bin/CryptoBoxTools.py

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import logging
import os
import re
logger = logging.getLogger("CryptoBox")
def getAvailablePartitions():
"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"):
p_parent = re.sub('[1-9]?[0-9]$', '', p_device)
if p_parent == p_device:
if [e for e in ret_list if re.search('^' + p_parent + '[1-9]?[0-9]$', 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 map(getAbsoluteDeviceName, ret_list)
except IOError:
logger.warning("Could not read /proc/partitions")
return []
def getAbsoluteDeviceName(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 = findMajorMinorOfDevice(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 = findMajorMinorDeviceName("/dev/mapper", major, minor)
if result: return result[0]
"now check all files in /dev"
result = findMajorMinorDeviceName("/dev", major, minor)
if result: return result[0]
return default
def findMajorMinorOfDevice(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 findMajorMinorDeviceName(dir, major, minor):
"returns the names of devices with the specified major and minor number"
collected = []
try:
subdirs = [os.path.join(dir, e) for e in os.listdir(dir) if (not os.path.islink(os.path.join(dir, e))) and os.path.isdir(os.path.join(dir, e))]
"do a recursive call to parse the directory tree"
for dirs in subdirs:
collected.extend(findMajorMinorDeviceName(dirs, major, minor))
"filter all device inodes in this directory"
collected.extend([os.path.realpath(os.path.join(dir, e)) for e in os.listdir(dir) if (os.major(os.stat(os.path.join(dir, e)).st_rdev) == major) and (os.minor(os.stat(os.path.join(dir, e)).st_rdev) == minor)])
## remove double entries
result = []
for e in collected:
if e not in result: result.append(e)
return result
except OSError:
return []
def getParentBlockDevices():
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(u'\D',p_major) or re.search(u'\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 map(getAbsoluteDeviceName, devs)
def isPartOfBlockDevice(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) = findMajorMinorOfDevice(parent)
(sub_major, sub_minor) = findMajorMinorOfDevice(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