#!/usr/bin/env python2.4

## check python version
import sys
(ver_major, ver_minor, ver_sub, ver_desc, ver_subsub) = sys.version_info
if (ver_major < 2) or ((ver_major == 2) and (ver_minor < 4)):
	sys.stderr.write("You need a python version >= 2.4\nCurrent version is:\n %s\n" % sys.version)
	sys.exit(1)

import subprocess
import os
import re
import logging
from CryptoBoxExceptions import *

"""exceptions:
	CBVolumeIsActive
	CBNameActivelyUsed
	CBInvalidName
	CBInvalidPassword
	CBInvalidType
	CBCreateError
	CBMountError
	CBChangePasswordError
	"""

class CryptoBoxContainer:

	Types = {
		"unused":0,
		"plain":1,
		"luks":2,
		"swap":3}
	

	__fsTypes = {
		"plain":["ext3", "ext2", "vfat", "reiser"],
		"swap":["swap"]}
	# TODO: more filesystem types? / check 'reiser'

	__dmDir = "/dev/mapper"


	def __init__(self, device, cbox):
		self.device = device
		self.cbox = cbox
		self.log = logging.getLogger("CryptoBox")
		self.resetObject()


	def getName(self):
		return self.name


	def setName(self, new_name):
		if new_name == self.name: return
		if self.isMounted():
			raise CBVolumeIsActive("the container must be inactive during renaming")
		if not re.search(r'^[a-zA-Z0-9_\.\- ]+$', new_name):
			raise CBInvalidName("the supplied new name contains illegal characters")
		"check for active partitions with the same name"
		prev_name_owner = self.cbox.getContainerList(filterName=new_name)
		if prev_name_owner:
			for a in prev_name_owner:
				if a.isMounted():
					raise CBNameActivelyUsed("the supplied new name is already in use for an active partition")
		if not self.cbox.setNameForUUID(self.uuid, new_name):
			raise CBContainerError("failed to change the volume name for unknown reasons")
		self.name = new_name


	def getDevice(self):
		return self.device


	def getType(self):
		return self.type


	def isMounted(self):
		return os.path.ismount(self.__getMountPoint())
	

	def getCapacity(self):
		"""return the current capacity state of the volume

		the volume may not be mounted
		the result is a tuple of values in megabyte:
			(size, available, used)
		"""
		info = os.statvfs(self.__getMountPoint())
		return (
			int(info.f_bsize*info.f_blocks/1024/1024),
			int(info.f_bsize*info.f_bavail/1024/1024),
			int(info.f_bsize*(info.f_blocks-info.f_bavail)/1024/1024))
	

	def getSize(self):
		"""return the size of the block device (_not_ of the filesystem)

		the result is a value in megabyte
		an error is indicated by "-1"
		"""
		import CryptoBoxTools
		return CryptoBoxTools.getBlockDeviceSize(self.device)


	def resetObject(self):
		"""	recheck the information about this container
			this is especially useful after changing the type via 'create'	"""
		self.uuid = self.__getUUID()
		self.type = self.__getTypeOfPartition()
		self.name = self.__getNameOfContainer()
		if self.type == self.Types["luks"]:
			self.mount = self.__mountLuks
			self.umount = self.__umountLuks
		elif self.type == self.Types["plain"]:
			self.mount = self.__mountPlain
			self.umount = self.__umountPlain


	def create(self, type, password=None):
		old_name = self.getName()
		if type == self.Types["luks"]:
			self.__createLuks(password)
		elif type == self.Types["plain"]:
			self.__createPlain()
		else:
			raise CBInvalidType("invalid container type (%d) supplied" % (type, ))
		## no exception was raised during creation -> we can continue
		## reset the properties (encryption state, ...) of the device
		self.resetObject()
		## restore the old name (must be after resetObject)
		self.setName(old_name)


	def changePassword(self, oldpw, newpw):
		if self.type != self.Types["luks"]:
			raise CBInvalidType("changing of password is possible only for luks containers")
		if not oldpw:
			raise CBInvalidPassword("no old password supplied for password change")
		if not newpw:
			raise CBInvalidPassword("no new password supplied for password change")
		"return if new and old passwords are the same"
		if oldpw == newpw: return
		if self.isMounted():
			raise CBVolumeIsActive("this container is currently active")
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		"remove any potential open luks mapping"
		self.__umountLuks()
		"create the luks header"
		proc = subprocess.Popen(
			shell = False,
			stdin = subprocess.PIPE,
			stdout = subprocess.PIPE,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["super"],
				self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
				"cryptsetup",
				"luksAddKey",
				self.device,
				"--batch-mode"])
		proc.stdin.write("%s\n%s" % (oldpw, newpw))
		(output, errout) = proc.communicate()
		if proc.returncode != 0:
			errorMsg = "Could not add a new luks key: %s - %s" % (output.strip(), errout.strip(), )
			self.log.error(errorMsg)
			raise CBChangePasswordError(errorMsg)
		## retrieve the key slot we used for unlocking
		keys_found = re.search(r'key slot (\d{1,3}) unlocked', output).groups()
		if keys_found:
			keyslot = int(keys_found[0])
		else:
			raise CBChangePasswordError("could not get the old key slot")
		"remove the old key"
		proc = subprocess.Popen(
			shell = False,
			stdin = None,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["cryptsetup"],
				"--batch-mode",
				"luksDelKey",
				self.device,
				"%d" % (keyslot, )])
		proc.wait()
		if proc.returncode != 0:
			errorMsg = "Could not remove the old luks key: %s" % (proc.stderr.read().strip(), )
			self.log.error(errorMsg)
			raise CBChangePasswordError(errorMsg)
		


	" ****************** internal stuff ********************* "

	def __getNameOfContainer(self):
		"retrieve the name of the container by querying the database"
		def_name = self.cbox.getNameForUUID(self.uuid)
		if def_name: return def_name
		"there is no name defined for this uuid - we will propose a good one"
		prefix = self.cbox.prefs["Main"]["DefaultVolumePrefix"]
		unused_found = False
		counter = 1
		while not unused_found:
			guess = prefix + str(counter)
			if self.cbox.getUUIDForName(guess):
				counter += 1
			else:
				unused_found = True
		self.cbox.setNameForUUID(self.uuid, guess)
		return guess


	def __getUUID(self):
		if self.__getTypeOfPartition() == self.Types["luks"]:
			guess = self.__getLuksUUID()
		else:
			guess = self.__getNonLuksUUID()
		## did we get a valid value?
		if guess:
			return guess
		else:
			## emergency default value
			return self.device.replace(os.path.sep, "_")


	def __getLuksUUID(self):
		"""get uuid for luks devices"""
		proc = subprocess.Popen(
			shell = False,
			stdout = subprocess.PIPE,
			stderr = subprocess.PIPE,
			args = [self.cbox.prefs["Programs"]["cryptsetup"],
				"luksUUID",
				self.device])
		(stdout, stderr) = proc.communicate()
		if proc.returncode != 0:
			self.cbox.log.info("could not retrieve luks uuid (%s): %s", (self.device, stderr.strip()))
			return None
		return stdout.strip()

	
	def __getNonLuksUUID(self):
		"""return UUID for ext2/3 and vfat filesystems"""
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.warn("Could not open %s" % (os.devnull, ))
		proc = subprocess.Popen(
			shell=False,
			stdout=subprocess.PIPE,
			stderr=subprocess.PIPE,
			args=[self.cbox.prefs["Programs"]["blkid"],
				"-s", "UUID",
				"-o", "value",
				"-c", os.devnull,
				"-w", os.devnull,
				self.device])
		(stdout, stderr) = proc.communicate()
		devnull.close()
		## execution failed?
		if proc.returncode != 0:
			self.log.info("retrieving of partition type (%s) via 'blkid' failed: %s - maybe it is encrypted?" % (self.device, stderr.strip()))
			return None
		## return output of blkid
		return stdout.strip()


	def __getTypeOfPartition(self):
		"retrieve the type of the given partition (see CryptoBoxContainer.Types)"
		if self.__isLuksPartition(): return self.Types["luks"]
		typeOfPartition = self.__getTypeIdOfPartition()
		if typeOfPartition in self.__fsTypes["plain"]:
			return self.Types["plain"]
		if typeOfPartition in self.__fsTypes["swap"]:
			return self.Types["swap"]
		return self.Types["unused"]


	def __getTypeIdOfPartition(self):
		"returns the type of the partition (see 'man blkid')"
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		proc = subprocess.Popen(
			shell=False,
			stdin=None,
			stdout=subprocess.PIPE,
			stderr=subprocess.PIPE,
			args=[self.cbox.prefs["Programs"]["blkid"],
				"-s", "TYPE",
				"-o", "value",
				"-c", os.devnull,
				"-w", os.devnull,
				self.device])
		proc.wait()
		output = proc.stdout.read().strip()
		if proc.returncode != 0:
			self.log.warn("retrieving of partition type via 'blkid' failed: %s" % (proc.stderr.read().strip(), ))
			return None
		devnull.close()
		return output


	def __isLuksPartition(self):
		"check if the given device is a luks partition"
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		proc = subprocess.Popen(
			shell = False,
			stdin = None,
			stdout = devnull,
			stderr = devnull,
			args = [
				self.cbox.prefs["Programs"]["cryptsetup"],
				"--batch-mode",
				"isLuks",
				self.device])
		proc.wait()
		devnull.close()
		return proc.returncode == 0


	def __getMountPoint(self):
		"return the name of the mountpoint of this volume"
		return os.path.join(self.cbox.prefs["Locations"]["MountParentDir"], self.name)


	def __mountLuks(self, password):
		"mount a luks partition"
		if not password:
			raise CBInvalidPassword("no password supplied for luksOpen")
		if self.isMounted(): raise CBVolumeIsActive("this container is already active")
		self.__umountLuks()
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		self.__cleanMountDirs()
		if not os.path.exists(self.__getMountPoint()):
			os.mkdir(self.__getMountPoint())
		if not os.path.exists(self.__getMountPoint()):
			errorMsg = "Could not create mountpoint (%s)" % (self.__getMountPoint(), )
			self.log.error(errorMsg)
			raise CBMountError(errorMsg)
		proc = subprocess.Popen(
			shell = False,
			stdin = subprocess.PIPE,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["super"],
				self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
				"cryptsetup",
				"luksOpen",
				self.device,
				self.name,
				"--batch-mode"])
		proc.stdin.write(password)
		(output, errout) = proc.communicate()
		if proc.returncode != 0:
			errorMsg = "Could not open the luks mapping: %s" % (errout.strip(), )
			self.log.warn(errorMsg)
			raise CBMountError(errorMsg)
		proc = subprocess.Popen(
			shell = False,
			stdin = None,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["super"],
				self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
				"mount",
				os.path.join(self.__dmDir, self.name),
				self.__getMountPoint()])
		proc.wait()
		if proc.returncode != 0:
			errorMsg = "Could not mount the filesystem: %s" % (proc.stderr.read().strip(), )
			self.log.warn(errorMsg)
			raise CBMountError(errorMsg)
		devnull.close()


	def __umountLuks(self):
		"umount a luks partition"
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		if self.isMounted():
			proc = subprocess.Popen(
				shell = False,
				stdin = None,
				stdout = devnull,
				stderr = subprocess.PIPE,
				args = [
					self.cbox.prefs["Programs"]["super"],
					self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
					"umount",
					self.__getMountPoint()])
			proc.wait()
			if proc.returncode != 0:
				errorMsg = "Could not umount the filesystem: %s" % (proc.stderr.read().strip(), )
				self.log.warn(errorMsg)
				raise CBUmountError(errorMsg)
		if os.path.exists(os.path.join(self.__dmDir, self.name)):
			proc = subprocess.Popen(
				shell = False,
				stdin = None,
				stdout = devnull,
				stderr = subprocess.PIPE,
				args = [
					self.cbox.prefs["Programs"]["super"],
					self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
					"cryptsetup",
					"luksClose",
					self.name,
					"--batch-mode"])
			proc.wait()
			if proc.returncode != 0:
				errorMsg = "Could not remove the luks mapping: %s" % (proc.stderr.read().strip(), )
				self.log.warn(errorMsg)
				raise CBUmountError(errorMsg)
		devnull.close()


	def __mountPlain(self):
		"mount a plaintext partition"
		if self.isMounted(): raise CBVolumeIsActive("this container is already active")
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		self.__cleanMountDirs()
		if not os.path.exists(self.__getMountPoint()):
			os.mkdir(self.__getMountPoint())
		if not os.path.exists(self.__getMountPoint()):
			errorMsg = "Could not create mountpoint (%s)" % (self.__getMountPoint(), )
			self.log.error(errorMsg)
			raise CBMountError(errorMsg)
		proc = subprocess.Popen(
			shell = False,
			stdin = None,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["super"],
				self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
				"mount",
				self.device,
				self.__getMountPoint()])
		proc.wait()
		if proc.returncode != 0:
			errorMsg = "Could not mount the filesystem: %s" % (proc.stderr.read().strip(), )
			self.log.warn(errorMsg)
			raise CBMountError(errorMsg)
		devnull.close()


	def __umountPlain(self):
		"umount a plaintext partition"
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		if self.isMounted():
			proc = subprocess.Popen(
				shell = False,
				stdin = None,
				stdout = devnull,
				stderr = subprocess.PIPE,
				args = [
					self.cbox.prefs["Programs"]["super"],
					self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
					"umount",
					self.__getMountPoint()])
			proc.wait()
			if proc.returncode != 0:
				errorMsg = "Could not umount the filesystem: %s" % (proc.stderr.read().strip(), )
				self.log.warn(errorMsg)
				raise CBUmountError(errorMsg)
		devnull.close()
	

	def __createPlain(self):
		"make a plaintext partition"
		if self.isMounted():
			raise CBVolumeIsActive("deactivate the partition before filesystem initialization")
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		proc = subprocess.Popen(
			shell = False,
			stdin = None,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["mkfs-data"],
				self.device])
		proc.wait()
		if proc.returncode != 0:
			errorMsg = "Could not create the filesystem: %s" % (proc.stderr.read().strip(), )
			self.log.error(errorMsg)
			raise CBCreateError(errorMsg)
		devnull.close()


	def __createLuks(self, password):
		"make a luks partition"
		if not password:
			raise CBInvalidPassword("no password supplied for new luks mapping")
		if self.isMounted():
			raise CBVolumeIsActive("deactivate the partition before filesystem initialization")
		devnull = None
		try:
			devnull = open(os.devnull, "w")
		except IOError:
			self.log.warn("Could not open %s" % (os.devnull, ))
		"remove any potential open luks mapping"
		self.__umountLuks()
		"create the luks header"
		proc = subprocess.Popen(
			shell = False,
			stdin = subprocess.PIPE,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["super"],
				self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
				"cryptsetup",
				"luksFormat",
				self.device,
				"--batch-mode",
				"--cipher", self.cbox.prefs["Main"]["DefaultCipher"],
				"--iter-time", "2000"])
		proc.stdin.write(password)
		(output, errout) = proc.communicate()
		if proc.returncode != 0:
			errorMsg = "Could not create the luks header: %s" % (errout.strip(), )
			self.log.error(errorMsg)
			raise CBCreateError(errorMsg)
		"open the luks container for mkfs"
		proc = subprocess.Popen(
			shell = False,
			stdin = subprocess.PIPE,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["super"],
				self.cbox.prefs["Programs"]["CryptoBoxRootActions"],
				"cryptsetup",
				"luksOpen",
				self.device,
				self.name,
				"--batch-mode"])
		proc.stdin.write(password)
		(output, errout) = proc.communicate()
		if proc.returncode != 0:
			errorMsg = "Could not open the new luks mapping: %s" % (errout.strip(), )
			self.log.error(errorMsg)
			raise CBCreateError(errorMsg)
		"make the filesystem"
		proc = subprocess.Popen(
			shell = False,
			stdin = None,
			stdout = devnull,
			stderr = subprocess.PIPE,
			args = [
				self.cbox.prefs["Programs"]["mkfs-data"],
				os.path.join(self.__dmDir, self.name)])
		proc.wait()
		"remove the mapping - for every exit status"
		self.__umountLuks()
		if proc.returncode != 0:
			errorMsg = "Could not create the filesystem: %s" % (proc.stderr.read().strip(), )
			self.log.error(errorMsg)
			"remove the luks mapping"
			raise CBCreateError(errorMsg)
		devnull.close()


	def __cleanMountDirs(self):
		"""	remove all unnecessary subdirs of the mount parent directory
			this should be called for every (u)mount	"""
		subdirs = os.listdir(self.cbox.prefs["Locations"]["MountParentDir"])
		for dir in subdirs:
			abs_dir = os.path.join(self.cbox.prefs["Locations"]["MountParentDir"], dir)
			if (not os.path.islink(abs_dir)) and os.path.isdir(abs_dir) and (not os.path.ismount(abs_dir)):
				os.rmdir(abs_dir)