How to use the portage.os.unlink function in portage

else:
			self._fetch_tmp_dir_info = 'distfiles'
			distdir = self.config.options.distfiles

		tmp_basename = self.distfile + '._emirrordist_fetch_.%s' % os.getpid()

		variables = {
			"DISTDIR": distdir,
			"URI":     uri,
			"FILE":    tmp_basename
		}

		self._fetch_tmp_file = os.path.join(distdir, tmp_basename)

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

		args = portage.util.shlex_split(default_fetchcommand)
		args = [portage.util.varexpand(x, mydict=variables)
			for x in args]

		args = [_unicode_encode(x,
			encoding=_encodings['fs'], errors='strict') for x in args]

		null_fd = os.open(os.devnull, os.O_RDONLY)
		fetcher = PopenProcess(background=self.background,
			proc=subprocess.Popen(args, stdin=null_fd,
			stdout=subprocess.PIPE, stderr=subprocess.STDOUT),
			scheduler=self.scheduler)
		os.close(null_fd)

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._make_layout_links()
		else:
			# out of space?
			msg = "%s %s copy failed unexpectedly: %s" % \
				(self.distfile, self._fetch_tmp_dir_info, copier.future.exception())
			self.scheduler.output(msg + '\n', background=True,
				log_path=self._log_path)
			logging.error(msg)

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:

try:
			if hashname not in hashfunc_keys:
				raise portage.exception.DigestException(hashname + \
					" hash function not available (needs dev-python/pycrypto)")
			myhash, mysize = hashfunc_map[hashname].checksum_file(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 _start(self):
		pkg = self.pkg
		pretend = self.pretend
		bintree = pkg.root_config.trees["bintree"]
		settings = bintree.settings
		pkg_path = self.pkg_path

		exists = os.path.exists(pkg_path)
		resume = exists and os.path.basename(pkg_path) in bintree.invalids
		if not (pretend or resume):
			# Remove existing file or broken symlink.
			try:
				os.unlink(pkg_path)
			except OSError:
				pass

		# urljoin doesn't work correctly with
		# unrecognized protocols like sftp
		if bintree._remote_has_index:
			instance_key = bintree.dbapi._instance_key(pkg.cpv)
			rel_uri = bintree._remotepkgs[instance_key].get("PATH")
			if not rel_uri:
				rel_uri = pkg.cpv + ".tbz2"
			remote_base_uri = bintree._remotepkgs[
				instance_key]["BASE_URI"]
			uri = remote_base_uri.rstrip("/") + "/" + rel_uri.lstrip("/")
		else:
			uri = settings["PORTAGE_BINHOST"].rstrip("/") + \
				"/" + pkg.pf + ".tbz2"

exitcode = 128 + signal.SIGINT

					#   0	Success
					#   1	Syntax or usage error
					#   2	Protocol incompatibility
					#   5	Error starting client-server protocol
					#  35	Timeout waiting for daemon connection
					if exitcode not in (0, 1, 2, 5, 35):
						# If the exit code is not among those listed above,
						# then we may have a partial/inconsistent sync
						# state, so our previously read timestamp as well
						# as the corresponding file can no longer be
						# trusted.
						timestamp = 0
						try:
							os.unlink(self.servertimestampfile)
						except OSError:
							pass
					else:
						updatecache_flg = True

				if exitcode in [0,1,3,4,11,14,20,21]:
					is_synced = True
		elif exitcode in [1,3,4,11,14,20,21]:
			is_synced = True
		else:
			# Code 2 indicates protocol incompatibility, which is expected
			# for servers with protocol < 29 that don't support
			# --prune-empty-directories.  Retry for a server that supports
			# at least rsync protocol version 29 (>=rsync-2.6.4).
			pass

	@return: a tuple of (removed, fstat_result), where removed is True if
		lock_path does not correspond to lock_fd, and False otherwise
	"""
	try:
		fstat_st = os.fstat(lock_fd)
	except OSError as e:
		if e.errno not in (errno.ENOENT, errno.ESTALE):
			_raise_exc(e)
		return (True, None)

	# Since stat is not reliable for removed files on NFS with the default
	# file attribute cache behavior ('ac' mount option), create a temporary
	# hardlink in order to prove that the file path exists on the NFS server.
	hardlink_path = hardlock_name(lock_path)
	try:
		os.unlink(hardlink_path)
	except OSError as e:
		if e.errno not in (errno.ENOENT, errno.ESTALE):
			_raise_exc(e)
	try:
		try:
			os.link(lock_path, hardlink_path)
		except OSError as e:
			if e.errno not in (errno.ENOENT, errno.ESTALE):
				_raise_exc(e)
			return (True, None)

		hardlink_stat = os.stat(hardlink_path)
		if hardlink_stat.st_ino != fstat_st.st_ino or hardlink_stat.st_dev != fstat_st.st_dev:
			# Create another hardlink in order to detect whether or not
			# hardlink inode numbers are expected to match. For example,
			# inode numbers are not expected to match for sshfs.

def unhardlink_lockfile(lockfilename, unlinkfile=True):
	myhardlock = hardlock_name(lockfilename)
	if unlinkfile and hardlink_is_mine(myhardlock, lockfilename):
		# Make sure not to touch lockfilename unless we really have a lock.
		try:
			os.unlink(lockfilename)
		except OSError:
			pass
	try:
		os.unlink(myhardlock)
	except OSError:
		pass

build_info = {
							"BINPKGMD5": "%s\n" % pkg._metadata["MD5"],
						}
						if pkg.build_id is not None:
							build_info["BUILD_ID"] = "%s\n" % pkg.build_id
						for k, v in build_info.items():
							with io.open(_unicode_encode(
								os.path.join(infoloc, k),
								encoding=_encodings['fs'], errors='strict'),
								mode='w', encoding=_encodings['repo.content'],
								errors='strict') as f:
								f.write(v)
			else:
				if "PORTAGE_BINPKG_TMPFILE" in mysettings:
					try:
						os.unlink(mysettings["PORTAGE_BINPKG_TMPFILE"])
					except OSError:
						pass

		elif returnpid:
			writemsg("!!! doebuild: %s\n" %
				_("returnpid is not supported for phase '%s'\n" % mydo),
				noiselevel=-1)

		if regular_actionmap_phase:
			# handled above
			pass
		elif mydo == "qmerge":
			# check to ensure install was run.  this *only* pops up when users
			# forget it and are using ebuild
			if not os.path.exists(
				os.path.join(mysettings["PORTAGE_BUILDDIR"], ".installed")):

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" %
						str(myentry) for myentry in myentries))
					self._apply_max_mtime(preserved_stats, 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