def write(self, sign=False, force=False):
		""" Write Manifest instance to disk, optionally signing it. Returns
		True if the Manifest is actually written, and False if the write
		is skipped due to existing Manifest being identical."""
		rval = False
		if not self.allow_create:
			return rval
		self.checkIntegrity()
		try:
			myentries = list(self._createManifestEntries())
			update_manifest = True
			existing_st = None
			if myentries and not force:
				try:
					f = io.open(_unicode_encode(self.getFullname(),
						encoding=_encodings['fs'], errors='strict'),
						mode='r', encoding=_encodings['repo.content'],
						errors='replace')
					oldentries = list(self._parseManifestLines(f))
					existing_st = os.fstat(f.fileno())
					f.close()
					if len(oldentries) == len(myentries):
						update_manifest = False
						for i in range(len(oldentries)):
							if oldentries[i] != myentries[i]:
								update_manifest = True
								break
				except (IOError, OSError) as e:
					if e.errno == errno.ENOENT:
						pass
					else:
						raise

			if update_manifest:
				if myentries or not (self.thin or self.allow_missing):
					# If myentries is empty, don't write an empty manifest
					# when thin or allow_missing is enabled. Except for
					# thin manifests with no DIST entries, myentries is
					# non-empty for all currently known use cases.
					write_atomic(self.getFullname(), "".join("%s\n" %
						_unicode(myentry) for myentry in myentries))
					self._apply_max_mtime(existing_st, myentries)
					rval = True
				else:
					# With thin manifest, there's no need to have
					# a Manifest file if there are no DIST entries.
					try:
						os.unlink(self.getFullname())
					except OSError as e:
						if e.errno != errno.ENOENT:
							raise
					rval = True

			if sign:
				self.sign()
		except (IOError, OSError) as e:
			if e.errno == errno.EACCES:
				raise PermissionDenied(str(e))
			raise
		return rval

	def _start(self):

		if self.background:
			# Automatically prevent color codes from showing up in logs,
			# since we're not displaying to a terminal anyway.
			self.settings['NOCOLOR'] = 'true'

		if self._enable_ipc_daemon:
			self.settings.pop('PORTAGE_EBUILD_EXIT_FILE', None)
			if self.phase not in self._phases_without_builddir:
				self.settings['PORTAGE_IPC_DAEMON'] = "1"
				self._start_ipc_daemon()
			else:
				self.settings.pop('PORTAGE_IPC_DAEMON', None)
		else:
			# Since the IPC daemon is disabled, use a simple tempfile based
			# approach to detect unexpected exit like in bug #190128.
			self.settings.pop('PORTAGE_IPC_DAEMON', None)
			if self.phase not in self._phases_without_builddir:
				exit_file = os.path.join(
					self.settings['PORTAGE_BUILDDIR'],
					'.exit_status')
				self.settings['PORTAGE_EBUILD_EXIT_FILE'] = exit_file
				try:
					os.unlink(exit_file)
				except OSError:
					if os.path.exists(exit_file):
						# make sure it doesn't exist
						raise
			else:
				self.settings.pop('PORTAGE_EBUILD_EXIT_FILE', None)

		SpawnProcess._start(self)

	def _start(self):
		"""
		Note: Unlike a normal AsynchronousTask.start() method,
		this one does all work is synchronously. The returncode
		attribute will be set before it returns.
		"""

		pkg = self.pkg
		root_config = pkg.root_config
		bintree = root_config.trees["bintree"]
		rval = os.EX_OK
		stdout_orig = sys.stdout
		stderr_orig = sys.stderr
		out = portage.StringIO()
		try:
			sys.stdout = out
			sys.stderr = out
			try:
				bintree.digestCheck(pkg)
			except portage.exception.FileNotFound:
				writemsg("!!! Fetching Binary failed " + \
					"for '%s'\n" % pkg.cpv, noiselevel=-1)
				rval = 1
			except portage.exception.DigestException as e:
				writemsg("\n!!! Digest verification failed:\n",
					noiselevel=-1)
				writemsg("!!! %s\n" % e.value[0],
					noiselevel=-1)
				writemsg("!!! Reason: %s\n" % e.value[1],
					noiselevel=-1)
				writemsg("!!! Got: %s\n" % e.value[2],
					noiselevel=-1)
				writemsg("!!! Expected: %s\n" % e.value[3],
					noiselevel=-1)
				rval = 1
			if rval == os.EX_OK:
				# If this was successful, discard the log here since otherwise
				# we'll get multiple logs for the same package.
				if self.logfile is not None:
					try:
						os.unlink(self.logfile)
					except OSError:
						pass
			else:
				pkg_path = bintree.getname(pkg.cpv)
				head, tail = os.path.split(pkg_path)
				temp_filename = _checksum_failure_temp_file(head, tail)
				writemsg("File renamed to '%s'\n" % (temp_filename,),
					noiselevel=-1)
		finally:
			sys.stdout = stdout_orig
			sys.stderr = stderr_orig

		msg = _unicode_decode(out.getvalue(),
			encoding=_encodings['content'], errors='replace')
		if msg:
			self.scheduler.output(msg, log_path=self.logfile)

		self.returncode = rval
		self.wait()

	def priming_commit(self, myupdates, myremoved, commitmessage):
		myfiles = myupdates + myremoved
		fd, commitmessagefile = tempfile.mkstemp(".repoman.msg")
		mymsg = os.fdopen(fd, "wb")
		mymsg.write(_unicode_encode(commitmessage))
		mymsg.close()

		separator = '-' * 78

		print()
		print(green("Using commit message:"))
		print(green(separator))
		print(commitmessage)
		print(green(separator))
		print()

		# Having a leading ./ prefix on file paths can trigger a bug in
		# the cvs server when committing files to multiple directories,
		# so strip the prefix.
		myfiles = [f.lstrip("./") for f in myfiles]

		retval = self.vcs_settings.changes.commit(myfiles, commitmessagefile)
		# cleanup the commit message before possibly exiting
		try:
			os.unlink(commitmessagefile)
		except OSError:
			pass
		if retval != os.EX_OK:
			writemsg_level(
				"!!! Exiting on %s (shell) "
				"error code: %s\n" % (self.vcs_settings.vcs, retval),
				level=logging.ERROR, noiselevel=-1)
			sys.exit(retval)

	def _init_ipc_fifos(self):

		input_fifo = os.path.join(
			self.settings['PORTAGE_BUILDDIR'], '.ipc_in')
		output_fifo = os.path.join(
			self.settings['PORTAGE_BUILDDIR'], '.ipc_out')

		for p in (input_fifo, output_fifo):

			st = None
			try:
				st = os.lstat(p)
			except OSError:
				os.mkfifo(p)
			else:
				if not stat.S_ISFIFO(st.st_mode):
					st = None
					try:
						os.unlink(p)
					except OSError:
						pass
					os.mkfifo(p)

			apply_secpass_permissions(p,
				uid=os.getuid(),
				gid=portage.data.portage_gid,
				mode=0o770, stat_cached=st)

		return (input_fifo, output_fifo)

	def close(self):
		"""Closes the temporary file, copies permissions (if possible),
		and performs the atomic replacement via os.rename().  If the abort()
		method has been called, then the temp file is closed and removed."""
		f = object.__getattribute__(self, '_file')
		real_name = object.__getattribute__(self, '_real_name')
		if not f.closed:
			try:
				f.close()
				if not object.__getattribute__(self, '_aborted'):
					try:
						apply_stat_permissions(f.name, os.stat(real_name))
					except OperationNotPermitted:
						pass
					except FileNotFound:
						pass
					except OSError as oe: # from the above os.stat call
						if oe.errno in (errno.ENOENT, errno.EPERM):
							pass
						else:
							raise
					os.rename(f.name, real_name)
			finally:
				# Make sure we cleanup the temp file
				# even if an exception is raised.
				try:
					os.unlink(f.name)
				except OSError as oe:
					pass

def perform_checksum(filename, hashname="MD5", calc_prelink=0):
	"""
	Run a specific checksum against a file. The filename can
	be either unicode or an encoded byte string. If filename
	is unicode then a UnicodeDecodeError will be raised if
	necessary.

	@param filename: File to run the checksum against
	@type filename: String
	@param hashname: The type of hash function to run
	@type hashname: String
	@param calc_prelink: Whether or not to reverse prelink before running the checksum
	@type calc_prelink: Integer
	@rtype: Tuple
	@return: The hash and size of the data
	"""
	global prelink_capable
	# Make sure filename is encoded with the correct encoding before
	# it is passed to spawn (for prelink) and/or the hash function.
	filename = _unicode_encode(filename,
		encoding=_encodings['fs'], errors='strict')
	myfilename = filename
	prelink_tmpfile = None
	try:
		if (calc_prelink and prelink_capable and
		    is_prelinkable_elf(filename)):
			# Create non-prelinked temporary file to checksum.
			# Files rejected by prelink are summed in place.
			try:
				tmpfile_fd, prelink_tmpfile = tempfile.mkstemp()
				try:
					retval = portage.process.spawn([PRELINK_BINARY,
						"--verify", filename], fd_pipes={1:tmpfile_fd})
				finally:
					os.close(tmpfile_fd)
				if retval == os.EX_OK:
					myfilename = prelink_tmpfile
			except portage.exception.CommandNotFound:
				# This happens during uninstallation of prelink.
				prelink_capable = False
		try:
			if hashname not in hashfunc_map:
				raise portage.exception.DigestException(hashname + \
					" hash function not available (needs dev-python/pycrypto)")
			myhash, mysize = hashfunc_map[hashname](myfilename)
		except (OSError, IOError) as e:
			if e.errno in (errno.ENOENT, errno.ESTALE):
				raise portage.exception.FileNotFound(myfilename)
			elif e.errno == portage.exception.PermissionDenied.errno:
				raise portage.exception.PermissionDenied(myfilename)
			raise
		return myhash, mysize
	finally:
		if prelink_tmpfile:
			try:
				os.unlink(prelink_tmpfile)
			except OSError as e:
				if e.errno != errno.ENOENT:
					raise
				del e

	def _testPipeLogger(self, test_string):

		producer = PopenProcess(proc=subprocess.Popen(
			["bash", "-c", self._echo_cmd % test_string],
			stdout=subprocess.PIPE, stderr=subprocess.STDOUT),
			scheduler=global_event_loop())

		fd, log_file_path = tempfile.mkstemp()
		try:

			consumer = PipeLogger(background=True,
				input_fd=producer.proc.stdout,
				log_file_path=log_file_path)

			producer.pipe_reader = consumer

			producer.start()
			producer.wait()

			self.assertEqual(producer.returncode, os.EX_OK)
			self.assertEqual(consumer.returncode, os.EX_OK)

			with open(log_file_path, 'rb') as f:
				content = f.read()

		finally:
			os.close(fd)
			os.unlink(log_file_path)

		return content.decode('ascii', 'replace')

	def _fetch_copier_exit(self, copier):

		self._assert_current(copier)

		try:
			os.unlink(self._fetch_tmp_file)
		except OSError:
			pass

		if self._was_cancelled():
			self.wait()
			return

		if copier.returncode == os.EX_OK:
			self._success()
			self.returncode = os.EX_OK
			self.wait()
		else:
			# out of space?
			msg = "%s %s copy failed unexpectedly" % \
				(self.distfile, self._fetch_tmp_dir_info)
			self.scheduler.output(msg + '\n', background=True,
				log_path=self._log_path)
			logging.error(msg)
			self.config.log_failure("%s\t%s\t%s" %
				(self.cpv, self.distfile, msg))
			self.config.file_failures[self.distfile] = self.cpv
			self.returncode = 1
			self.wait()

	def _hardlink_atomic(self, src, dest, dir_info):

		head, tail = os.path.split(dest)
		hardlink_tmp = os.path.join(head, ".%s._mirrordist_hardlink_.%s" % \
			(tail, os.getpid()))

		try:
			try:
				os.link(src, hardlink_tmp)
			except OSError as e:
				if e.errno != errno.EXDEV:
					msg = "hardlink %s from %s failed: %s" % \
						(self.distfile, dir_info, e)
					self.scheduler.output(msg + '\n', background=True,
						log_path=self._log_path)
					logging.error(msg)
				return False

			try:
				os.rename(hardlink_tmp, dest)
			except OSError as e:
				msg = "hardlink rename '%s' from %s failed: %s" % \
					(self.distfile, dir_info, e)
				self.scheduler.output(msg + '\n', background=True,
					log_path=self._log_path)
				logging.error(msg)
				return False
		finally:
			try:
				os.unlink(hardlink_tmp)
			except OSError:
				pass

		return True

	def _testPipeLogger(self, test_string):

		producer = PopenProcess(proc=subprocess.Popen(
			["bash", "-c", self._echo_cmd % test_string],
			stdout=subprocess.PIPE, stderr=subprocess.STDOUT),
			scheduler=global_event_loop())

		fd, log_file_path = tempfile.mkstemp()
		try:

			consumer = PipeLogger(background=True,
				input_fd=os.dup(producer.proc.stdout.fileno()),
				log_file_path=log_file_path)

			# Close the stdout pipe, since we duplicated it, and it
			# must be closed in order to avoid a ResourceWarning.
			producer.proc.stdout.close()
			producer.pipe_reader = consumer

			producer.start()
			producer.wait()

			self.assertEqual(producer.returncode, os.EX_OK)
			self.assertEqual(consumer.returncode, os.EX_OK)

			with open(log_file_path, 'rb') as f:
				content = f.read()

		finally:
			os.close(fd)
			os.unlink(log_file_path)

		return content.decode('ascii', 'replace')

def collect_ebuild_messages(path):
	""" Collect elog messages generated by the bash logging function stored 
		at 'path'.
	"""
	mylogfiles = None
	try:
		mylogfiles = os.listdir(path)
	except OSError:
		pass
	# shortcut for packages without any messages
	if not mylogfiles:
		return {}
	# exploit listdir() file order so we process log entries in chronological order
	mylogfiles.reverse()
	logentries = {}
	for msgfunction in mylogfiles:
		filename = os.path.join(path, msgfunction)
		if msgfunction not in EBUILD_PHASES:
			writemsg(_("!!! can't process invalid log file: %s\n") % filename,
				noiselevel=-1)
			continue
		if not msgfunction in logentries:
			logentries[msgfunction] = []
		lastmsgtype = None
		msgcontent = []
		f = io.open(_unicode_encode(filename,
			encoding=_encodings['fs'], errors='strict'),
			mode='r', encoding=_encodings['repo.content'], errors='replace')
		for l in f:
			l = l.rstrip('\n')
			if not l:
				continue
			try:
				msgtype, msg = l.split(" ", 1)
			except ValueError:
				writemsg(_("!!! malformed entry in "
					"log file: '%s'\n") % filename, noiselevel=-1)
				continue

			if lastmsgtype is None:
				lastmsgtype = msgtype
			
			if msgtype == lastmsgtype:
				msgcontent.append(msg)
			else:
				if msgcontent:
					logentries[msgfunction].append((lastmsgtype, msgcontent))
				msgcontent = [msg]
			lastmsgtype = msgtype
		f.close()
		if msgcontent:
			logentries[msgfunction].append((lastmsgtype, msgcontent))

	# clean logfiles to avoid repetitions
	for f in mylogfiles:
		try:
			os.unlink(os.path.join(path, f))
		except OSError:
			pass
	return logentries

def _archive_copy(src_st, src_path, dest_path):
	"""
	Copy file from src_path to dest_path. Regular files and symlinks
	are supported. If an EnvironmentError occurs, then it is logged
	to stderr.

	@param src_st: source file lstat result
	@type src_st: posix.stat_result
	@param src_path: source file path
	@type src_path: str
	@param dest_path: destination file path
	@type dest_path: str
	"""
	# Remove destination file in order to ensure that the following
	# symlink or copy2 call won't fail (see bug #535850).
	try:
		os.unlink(dest_path)
	except OSError:
		pass
	try:
		if stat.S_ISLNK(src_st.st_mode):
			os.symlink(os.readlink(src_path), dest_path)
		else:
			shutil.copy2(src_path, dest_path)
	except EnvironmentError as e:
		portage.util.writemsg(
			_('dispatch-conf: Error copying %(src_path)s to '
			'%(dest_path)s: %(reason)s\n') % {
				"src_path": src_path,
				"dest_path": dest_path,
				"reason": e
			}, noiselevel=-1)

	def _success(self):
		if not self._previously_added:
			size = self.digests["size"]
			self.config.added_byte_count += size
			self.config.added_file_count += 1
			self.config.log_success("%s\t%s\tadded %i bytes" %
				(self.cpv, self.distfile, size))

		if self._log_path is not None:
			if not self.config.options.dry_run:
				try:
					os.unlink(self._log_path)
				except OSError:
					pass

		if self.config.options.recycle_dir is not None:

			recycle_file = os.path.join(
				self.config.options.recycle_dir, self.distfile)

			if self.config.options.dry_run:
				if os.path.exists(recycle_file):
					logging.info("dry-run: delete '%s' from recycle" %
						(self.distfile,))
			else:
				try:
					os.unlink(recycle_file)
				except OSError:
					pass
				else:
					logging.debug("delete '%s' from recycle" %
						(self.distfile,))

	def add_manifest(self, mymanifests, myheaders, myupdates, myremoved,
					commitmessage):
		myfiles = mymanifests[:]
		# If there are no header (SVN/CVS keywords) changes in
		# the files, this Manifest commit must include the
		# other (yet uncommitted) files.
		if not myheaders:
			myfiles += myupdates
			myfiles += myremoved
		myfiles.sort()

		fd, commitmessagefile = tempfile.mkstemp(".repoman.msg")
		mymsg = os.fdopen(fd, "wb")
		mymsg.write(_unicode_encode(commitmessage))
		mymsg.close()

		retval = self.vcs_settings.changes.commit(myfiles, commitmessagefile)
		# cleanup the commit message before possibly exiting
		try:
			os.unlink(commitmessagefile)
		except OSError:
			pass
		if retval != os.EX_OK:
			writemsg_level(
				"!!! Exiting on %s (shell) "
				"error code: %s\n" % (self.vcs_settings.vcs, retval),
				level=logging.ERROR, noiselevel=-1)
			sys.exit(retval)

def _prepare_fake_distdir(settings, alist):
	orig_distdir = settings["DISTDIR"]
	edpath = os.path.join(settings["PORTAGE_BUILDDIR"], "distdir")
	portage.util.ensure_dirs(edpath, gid=portage_gid, mode=0o755)

	# Remove any unexpected files or directories.
	for x in os.listdir(edpath):
		symlink_path = os.path.join(edpath, x)
		st = os.lstat(symlink_path)
		if x in alist and stat.S_ISLNK(st.st_mode):
			continue
		if stat.S_ISDIR(st.st_mode):
			shutil.rmtree(symlink_path)
		else:
			os.unlink(symlink_path)

	# Check for existing symlinks and recreate if necessary.
	for x in alist:
		symlink_path = os.path.join(edpath, x)
		target = os.path.join(orig_distdir, x)
		try:
			link_target = os.readlink(symlink_path)
		except OSError:
			os.symlink(target, symlink_path)
		else:
			if link_target != target:
				os.unlink(symlink_path)
				os.symlink(target, symlink_path)

	def testLogfile(self):
		logfile = None
		try:
			fd, logfile = tempfile.mkstemp()
			os.close(fd)
			null_fd = os.open('/dev/null', os.O_RDWR)
			test_string = 2 * "blah blah blah\n"
			task_scheduler = TaskScheduler()
			proc = SpawnProcess(
				args=[BASH_BINARY, "-c",
				"echo -n '%s'" % test_string],
				env={}, fd_pipes={0:sys.stdin.fileno(), 1:null_fd, 2:null_fd},
				scheduler=task_scheduler.sched_iface,
				logfile=logfile)
			task_scheduler.add(proc)
			task_scheduler.run()
			os.close(null_fd)
			f = codecs.open(_unicode_encode(logfile,
				encoding=_encodings['fs'], errors='strict'),
				mode='r', encoding=_encodings['content'], errors='strict')
			log_content = f.read()
			f.close()
			# When logging passes through a pty, this comparison will fail
			# unless the oflag terminal attributes have the termios.OPOST
			# bit disabled. Otherwise, tranformations such as \n -> \r\n
			# may occur.
			self.assertEqual(test_string, log_content)
		finally:
			if logfile:
				try:
					os.unlink(logfile)
				except EnvironmentError as e:
					if e.errno != errno.ENOENT:
						raise
					del e

	def _recycle_copier_exit(self, copier):

		self._assert_current(copier)
		if self._was_cancelled():
			self.wait()
			return

		success = True
		if copier.returncode == os.EX_OK:

			try:
				os.unlink(copier.src_path)
			except OSError as e:
				if e.errno not in (errno.ENOENT, errno.ESTALE):
					logging.error("%s unlink failed in distfiles: %s" %
						(self.distfile, e))
					success = False

		else:
			logging.error(("%s copy from distfiles "
				"to recycle failed: %s") % (self.distfile, e))
			success = False

		if success:
			self._success()
			self.returncode = os.EX_OK
		else:
			self.returncode = 1

		self._current_task = None
		self.wait()

 def clean_log(self):
     """Discard existing log."""
     settings = self.settings
     log_file = settings.get("PORTAGE_LOG_FILE")
     if log_file is not None and os.path.isfile(log_file):
         try:
             os.unlink(log_file)
         except OSError:
             pass

	def _start(self):

		distfile_path = os.path.join(
			self.config.options.distfiles, self.distfile)

		if self.config.options.recycle_dir is not None:
			distfile_path = os.path.join(self.config.options.distfiles, self.distfile)
			recycle_path = os.path.join(
				self.config.options.recycle_dir, self.distfile)
			if self.config.options.dry_run:
				logging.info(("dry-run: move '%s' from "
					"distfiles to recycle") % self.distfile)
			else:
				logging.debug(("move '%s' from "
					"distfiles to recycle") % self.distfile)
				try:
					os.rename(distfile_path, recycle_path)
				except OSError as e:
					if e.errno != errno.EXDEV:
						logging.error(("rename %s from distfiles to "
							"recycle failed: %s") % (self.distfile, e))
				else:
					self.returncode = os.EX_OK
					self._async_wait()
					return

				self._start_task(
					FileCopier(src_path=distfile_path,
						dest_path=recycle_path,
						background=False),
					self._recycle_copier_exit)
				return

		success = True

		if self.config.options.dry_run:
			logging.info(("dry-run: delete '%s' from "
				"distfiles") % self.distfile)
		else:
			logging.debug(("delete '%s' from "
				"distfiles") % self.distfile)
			try:
				os.unlink(distfile_path)
			except OSError as e:
				if e.errno not in (errno.ENOENT, errno.ESTALE):
					logging.error("%s unlink failed in distfiles: %s" %
						(self.distfile, e))
					success = False

		if success:
			self._success()
			self.returncode = os.EX_OK
		else:
			self.returncode = 1

		self._async_wait()