def testWakeupFdSigchld(self):
		"""
		This is expected to trigger a bunch of messages like the following
		unless the fix for bug 655656 works as intended:

		Exception ignored when trying to write to the signal wakeup fd:
		BlockingIOError: [Errno 11] Resource temporarily unavailable
		"""

		script = """
import os
import signal
import sys

import portage

# In order to avoid potential interference with API consumers, wakeup
# fd handling is enabled only when portage._interal_caller is True.
portage._internal_caller = True

from portage.util.futures import asyncio

loop = asyncio._wrap_loop()

# Cause the loop to register a child watcher.
proc = loop.run_until_complete(asyncio.create_subprocess_exec('sleep', '0', loop=loop))
loop.run_until_complete(proc.wait())

for i in range(8192):
	os.kill(os.getpid(), signal.SIGCHLD)

# Verify that the child watcher still works correctly
# (this will hang if it doesn't).
proc = loop.run_until_complete(asyncio.create_subprocess_exec('sleep', '0', loop=loop))
loop.run_until_complete(proc.wait())
loop.close()
sys.stdout.write('success')
sys.exit(os.EX_OK)
"""

		pythonpath = os.environ.get('PYTHONPATH', '').strip().split(':')
		if not pythonpath or pythonpath[0] != PORTAGE_PYM_PATH:
			pythonpath = [PORTAGE_PYM_PATH] + pythonpath
		pythonpath = ':'.join(filter(None, pythonpath))

		proc = subprocess.Popen(
			[portage._python_interpreter, '-c', script],
			stdout=subprocess.PIPE, stderr=subprocess.STDOUT,
			env=dict(os.environ, PYTHONPATH=pythonpath))

		out, err = proc.communicate()
		try:
			self.assertEqual(out[:100], b'success')
		except Exception:
			portage.writemsg(''.join('{}\n'.format(line)
				for line in out.decode(errors='replace').splitlines()[:50]),
				noiselevel=-1)
			raise

		self.assertEqual(proc.wait(), os.EX_OK)

	def _wait(self):

		AsyncScheduler._wait(self)

		portdb = self._portdb
		dead_nodes = {}

		self._termination_check()
		if self._terminated_tasks:
			portdb.flush_cache()
			self.returncode = self._cancelled_returncode
			return self.returncode

		if self._global_cleanse:
			for mytree in portdb.porttrees:
				try:
					dead_nodes[mytree] = set(portdb.auxdb[mytree])
				except CacheError as e:
					portage.writemsg("Error listing cache entries for " + \
						"'%s': %s, continuing...\n" % (mytree, e),
						noiselevel=-1)
					del e
					dead_nodes = None
					break
		else:
			cp_set = self._cp_set
			cpv_getkey = portage.cpv_getkey
			for mytree in portdb.porttrees:
				try:
					dead_nodes[mytree] = set(cpv for cpv in \
						portdb.auxdb[mytree] \
						if cpv_getkey(cpv) in cp_set)
				except CacheError as e:
					portage.writemsg("Error listing cache entries for " + \
						"'%s': %s, continuing...\n" % (mytree, e),
						noiselevel=-1)
					del e
					dead_nodes = None
					break

		if dead_nodes:
			for y in self._valid_pkgs:
				for mytree in portdb.porttrees:
					if portdb.findname2(y, mytree=mytree)[0]:
						dead_nodes[mytree].discard(y)

			for mytree, nodes in dead_nodes.items():
				auxdb = portdb.auxdb[mytree]
				for y in nodes:
					try:
						del auxdb[y]
					except (KeyError, CacheError):
						pass

		portdb.flush_cache()
		return self.returncode

	def run(self):

		portdb = self._portdb
		from portage.cache.cache_errors import CacheError
		dead_nodes = {}

		while self._schedule():
			self._poll_loop()

		while self._jobs:
			self._poll_loop()

		if self._terminated_tasks:
			self.returncode = 1
			return

		if self._global_cleanse:
			for mytree in portdb.porttrees:
				try:
					dead_nodes[mytree] = set(portdb.auxdb[mytree])
				except CacheError as e:
					portage.writemsg("Error listing cache entries for " + \
						"'%s': %s, continuing...\n" % (mytree, e),
						noiselevel=-1)
					del e
					dead_nodes = None
					break
		else:
			cp_set = self._cp_set
			cpv_getkey = portage.cpv_getkey
			for mytree in portdb.porttrees:
				try:
					dead_nodes[mytree] = set(cpv for cpv in \
						portdb.auxdb[mytree] \
						if cpv_getkey(cpv) in cp_set)
				except CacheError as e:
					portage.writemsg("Error listing cache entries for " + \
						"'%s': %s, continuing...\n" % (mytree, e),
						noiselevel=-1)
					del e
					dead_nodes = None
					break

		if dead_nodes:
			for y in self._valid_pkgs:
				for mytree in portdb.porttrees:
					if portdb.findname2(y, mytree=mytree)[0]:
						dead_nodes[mytree].discard(y)

			for mytree, nodes in dead_nodes.items():
				auxdb = portdb.auxdb[mytree]
				for y in nodes:
					try:
						del auxdb[y]
					except (KeyError, CacheError):
						pass

	def _task_exit(self, task):

		if task.returncode != os.EX_OK:
			if not self._terminated_tasks:
				portage.writemsg(
					"Error processing %s%s%s, continuing...\n" %
					(task.cp, _repo_separator, task.repo_config.name),
					noiselevel=-1)

		AsyncScheduler._task_exit(self, task)

def setexec(ctx="\n"):
	ctx = _unicode_encode(ctx, encoding=_encodings['content'], errors='strict')
	if selinux.setexeccon(ctx) < 0:
		ctx = _unicode_decode(ctx, encoding=_encodings['content'],
			errors='replace')
		if selinux.security_getenforce() == 1:
			raise OSError(_("Failed setting exec() context \"%s\".") % ctx)
		else:
			portage.writemsg("!!! " + \
				_("Failed setting exec() context \"%s\".") % ctx, \
				noiselevel=-1)

	def _cleanup(self):
		super(MetadataRegen, self)._cleanup()

		portdb = self._portdb
		dead_nodes = {}

		if self._terminated.is_set():
			portdb.flush_cache()
			return

		if self._global_cleanse:
			for mytree in portdb.porttrees:
				try:
					dead_nodes[mytree] = set(portdb.auxdb[mytree])
				except CacheError as e:
					portage.writemsg("Error listing cache entries for " + \
						"'%s': %s, continuing...\n" % (mytree, e),
						noiselevel=-1)
					del e
					dead_nodes = None
					break
		else:
			cp_set = self._cp_set
			cpv_getkey = portage.cpv_getkey
			for mytree in portdb.porttrees:
				try:
					dead_nodes[mytree] = set(cpv for cpv in \
						portdb.auxdb[mytree] \
						if cpv_getkey(cpv) in cp_set)
				except CacheError as e:
					portage.writemsg("Error listing cache entries for " + \
						"'%s': %s, continuing...\n" % (mytree, e),
						noiselevel=-1)
					del e
					dead_nodes = None
					break

		if dead_nodes:
			for y in self._valid_pkgs:
				for mytree in portdb.porttrees:
					if portdb.findname2(y, mytree=mytree)[0]:
						dead_nodes[mytree].discard(y)

			for mytree, nodes in dead_nodes.items():
				auxdb = portdb.auxdb[mytree]
				for y in nodes:
					try:
						del auxdb[y]
					except (KeyError, CacheError):
						pass

		portdb.flush_cache()

	def sign_manifest(self, myupdates, myremoved, mymanifests):
		try:
			for x in sorted(vcs_files_to_cps(
				chain(myupdates, myremoved, mymanifests),
				self.scanner.repolevel, self.scanner.reposplit, self.scanner.categories)):
				self.repoman_settings["O"] = os.path.join(self.repo_settings.repodir, x)
				manifest_path = os.path.join(self.repoman_settings["O"], "Manifest")
				if not need_signature(manifest_path):
					continue
				gpgsign(manifest_path, self.repoman_settings, self.options)
		except portage.exception.PortageException as e:
			portage.writemsg("!!! %s\n" % str(e))
			portage.writemsg("!!! Disabled FEATURES='sign'\n")
			self.repo_settings.sign_manifests = False

	def _task_exit(self, metadata_process):

		if metadata_process.returncode != os.EX_OK:
			self._valid_pkgs.discard(metadata_process.cpv)
			if not self._terminated_tasks:
				portage.writemsg("Error processing %s, continuing...\n" % \
					(metadata_process.cpv,), noiselevel=-1)

		if self._consumer is not None:
			# On failure, still notify the consumer (in this case the metadata
			# argument is None).
			self._consumer(metadata_process.cpv,
				metadata_process.repo_path,
				metadata_process.metadata,
				metadata_process.ebuild_hash,
				metadata_process.eapi_supported)

		AsyncScheduler._task_exit(self, metadata_process)

	def _metadata_exit(self, metadata_process):
		self._jobs -= 1
		if metadata_process.returncode != os.EX_OK:
			self.returncode = 1
			self._error_count += 1
			self._valid_pkgs.discard(metadata_process.cpv)
			portage.writemsg("Error processing %s, continuing...\n" % \
				(metadata_process.cpv,), noiselevel=-1)

		if self._consumer is not None:
			# On failure, still notify the consumer (in this case the metadata
			# argument is None).
			self._consumer(metadata_process.cpv,
				metadata_process.ebuild_path,
				metadata_process.repo_path,
				metadata_process.metadata)

		self._schedule()

	def _iter_tasks(self):
		portdb = self._portdb
		distdir = portdb.settings["DISTDIR"]
		disabled_repos = set()

		for cp in self._cp_iter:
			if self._terminated.is_set():
				break
			# We iterate over portdb.porttrees, since it's common to
			# tweak this attribute in order to adjust repo selection.
			for mytree in portdb.porttrees:
				if self._terminated.is_set():
					break
				repo_config = portdb.repositories.get_repo_for_location(mytree)
				if not repo_config.create_manifest:
					if repo_config.name not in disabled_repos:
						disabled_repos.add(repo_config.name)
						portage.writemsg(
							_(">>> Skipping creating Manifest for %s%s%s; "
							"repository is configured to not use them\n") %
							(cp, _repo_separator, repo_config.name),
							noiselevel=-1)
					continue
				cpv_list = portdb.cp_list(cp, mytree=[repo_config.location])
				if not cpv_list:
					continue
				fetchlist_dict = {}
				try:
					for cpv in cpv_list:
						fetchlist_dict[cpv] = \
							list(portdb.getFetchMap(cpv, mytree=mytree))
				except InvalidDependString as e:
					portage.writemsg(
						_("!!! %s%s%s: SRC_URI: %s\n") %
						(cp, _repo_separator, repo_config.name, e),
						noiselevel=-1)
					self._error_count += 1
					continue

				yield ManifestTask(cp=cp, distdir=distdir,
					fetchlist_dict=fetchlist_dict, repo_config=repo_config,
					gpg_cmd=self._gpg_cmd, gpg_vars=self._gpg_vars,
					force_sign_key=self._force_sign_key)

	def _set_rsync_defaults(self):
		portage.writemsg("PORTAGE_RSYNC_OPTS empty or unset, using hardcoded defaults\n")
		rsync_opts = [
			"--recursive",    # Recurse directories
			"--links",        # Consider symlinks
			"--safe-links",   # Ignore links outside of tree
			"--perms",        # Preserve permissions
			"--times",        # Preserive mod times
			"--omit-dir-times",
			"--compress",     # Compress the data transmitted
			"--force",        # Force deletion on non-empty dirs
			"--whole-file",   # Don't do block transfers, only entire files
			"--delete",       # Delete files that aren't in the master tree
			"--stats",        # Show final statistics about what was transfered
			"--human-readable",
			"--timeout="+str(self.timeout), # IO timeout if not done in X seconds
			"--exclude=/distfiles",   # Exclude distfiles from consideration
			"--exclude=/local",       # Exclude local     from consideration
			"--exclude=/packages",    # Exclude packages  from consideration
		]
		return rsync_opts

	def _run(self):
		mf = self.repo_config.load_manifest(
			os.path.join(self.repo_config.location, self.cp),
			self.distdir, fetchlist_dict=self.fetchlist_dict)

		try:
			mf.create(assumeDistHashesAlways=True)
		except FileNotFound as e:
			portage.writemsg(_("!!! File %s doesn't exist, can't update "
				"Manifest\n") % e, noiselevel=-1)
			return 1

		except PortagePackageException as e:
			portage.writemsg(("!!! %s\n") % (e,), noiselevel=-1)
			return 1

		try:
			modified = mf.write(sign=False)
		except PermissionDenied as e:
			portage.writemsg("!!! %s: %s\n" % (_("Permission Denied"), e,),
				noiselevel=-1)
			return 1
		else:
			if modified:
				return self.MODIFIED
			else:
				return os.EX_OK

def setexec(ctx="\n"):
	ctx = _native_string(ctx, encoding=_encodings['content'], errors='strict')
	rc = 0
	try:
		rc = selinux.setexeccon(ctx)
	except OSError:
		msg = _("Failed to set new SELinux execution context. " + \
			"Is your current SELinux context allowed to run Portage?")
		if selinux.security_getenforce() == 1:
			raise OSError(msg)
		else:
			portage.writemsg("!!! %s\n" % msg, noiselevel=-1)

	if rc < 0:
		if sys.hexversion < 0x3000000:
			ctx = _unicode_decode(ctx, encoding=_encodings['content'], errors='replace')
		if selinux.security_getenforce() == 1:
			raise OSError(_("Failed setting exec() context \"%s\".") % ctx)
		else:
			portage.writemsg("!!! " + \
				_("Failed setting exec() context \"%s\".") % ctx, \
				noiselevel=-1)

	def _iter_tasks(self):
		portdb = self._portdb
		distdir = portdb.settings["DISTDIR"]
		disabled_repos = set()

		for cp in self._cp_iter:
			if self._terminated.is_set():
				break
			# We iterate over portdb.porttrees, since it's common to
			# tweak this attribute in order to adjust repo selection.
			for mytree in portdb.porttrees:
				if self._terminated.is_set():
					break
				repo_config = portdb.repositories.get_repo_for_location(mytree)
				if not repo_config.create_manifest:
					if repo_config.name not in disabled_repos:
						disabled_repos.add(repo_config.name)
						portage.writemsg(
							_(">>> Skipping creating Manifest for %s%s%s; "
							"repository is configured to not use them\n") %
							(cp, _repo_separator, repo_config.name),
							noiselevel=-1)
					continue
				cpv_list = portdb.cp_list(cp, mytree=[repo_config.location])
				if not cpv_list:
					continue

				# Use _async_manifest_fetchlist(max_jobs=1), since we
				# spawn concurrent ManifestTask instances.
				yield ManifestTask(cp=cp, distdir=distdir,
					fetchlist_dict=_async_manifest_fetchlist(
						portdb, repo_config, cp, cpv_list=cpv_list,
						max_jobs=1, loop=self._event_loop),
					repo_config=repo_config,
					gpg_cmd=self._gpg_cmd, gpg_vars=self._gpg_vars,
					force_sign_key=self._force_sign_key)

    def _validate_rsync_opts(self, rsync_opts, syncuri):
        # The below validation is not needed when using the above hardcoded
        # defaults.

        portage.writemsg("Using PORTAGE_RSYNC_OPTS instead of hardcoded defaults\n", 1)
        rsync_opts.extend(portage.util.shlex_split(self.settings.get("PORTAGE_RSYNC_OPTS", "")))
        for opt in ("--recursive", "--times"):
            if opt not in rsync_opts:
                portage.writemsg(
                    yellow("WARNING:") + " adding required option " + "%s not included in PORTAGE_RSYNC_OPTS\n" % opt
                )
                rsync_opts.append(opt)

        for exclude in ("distfiles", "local", "packages"):
            opt = "--exclude=/%s" % exclude
            if opt not in rsync_opts:
                portage.writemsg(
                    yellow("WARNING:")
                    + " adding required option %s not included in " % opt
                    + "PORTAGE_RSYNC_OPTS (can be overridden with --exclude='!')\n"
                )
                rsync_opts.append(opt)

        if syncuri.rstrip("/").endswith(".gentoo.org/gentoo-portage"):

            def rsync_opt_startswith(opt_prefix):
                for x in rsync_opts:
                    if x.startswith(opt_prefix):
                        return (1, False)
                return (0, False)

            if not rsync_opt_startswith("--timeout="):
                rsync_opts.append("--timeout=%d" % self.timeout)

            for opt in ("--compress", "--whole-file"):
                if opt not in rsync_opts:
                    portage.writemsg(
                        yellow("WARNING:")
                        + " adding required option "
                        + "%s not included in PORTAGE_RSYNC_OPTS\n" % opt
                    )
                    rsync_opts.append(opt)
        return rsync_opts

	def perform(self, qa_output):
		myunadded, mydeleted = self._vcs_unadded()

		myautoadd = self._vcs_autoadd(myunadded)

		self._vcs_deleted(mydeleted)

		changes = self.get_vcs_changed(mydeleted)

		mynew, mychanged, myremoved, no_expansion, expansion = changes

		# Manifests need to be regenerated after all other commits, so don't commit
		# them now even if they have changed.
		mymanifests = set()
		myupdates = set()
		for f in mychanged + mynew:
			if "Manifest" == os.path.basename(f):
				mymanifests.add(f)
			else:
				myupdates.add(f)
		myupdates.difference_update(myremoved)
		myupdates = list(myupdates)
		mymanifests = list(mymanifests)
		myheaders = []

		commitmessage = self.options.commitmsg
		if self.options.commitmsgfile:
			try:
				f = io.open(
					_unicode_encode(
						self.options.commitmsgfile,
						encoding=_encodings['fs'], errors='strict'),
					mode='r', encoding=_encodings['content'], errors='replace')
				commitmessage = f.read()
				f.close()
				del f
			except (IOError, OSError) as e:
				if e.errno == errno.ENOENT:
					portage.writemsg(
						"!!! File Not Found:"
						" --commitmsgfile='%s'\n" % self.options.commitmsgfile)
				else:
					raise
		if not commitmessage or not commitmessage.strip():
			commitmessage = self.get_new_commit_message(qa_output)

		commitmessage = commitmessage.rstrip()

		myupdates, broken_changelog_manifests = self.changelogs(
					myupdates, mymanifests, myremoved, mychanged, myautoadd,
					mynew, commitmessage)

		commit_footer = self.get_commit_footer()
		commitmessage += commit_footer

		print("* %s files being committed..." % green(str(len(myupdates))), end=' ')

		if self.vcs_settings.vcs not in ('cvs', 'svn'):
			# With git, bzr and hg, there's never any keyword expansion, so
			# there's no need to regenerate manifests and all files will be
			# committed in one big commit at the end.
			print()
		elif not self.repo_settings.repo_config.thin_manifest:
			self.thick_manifest(myupdates, myheaders, no_expansion, expansion)

		logging.info("myupdates: %s", myupdates)
		logging.info("myheaders: %s", myheaders)

		uq = UserQuery(self.options)
		if self.options.ask and uq.query('Commit changes?', True) != 'Yes':
			print("* aborting commit.")
			sys.exit(128 + signal.SIGINT)

		# Handle the case where committed files have keywords which
		# will change and need a priming commit before the Manifest
		# can be committed.
		if (myupdates or myremoved) and myheaders:
			self.priming_commit(myupdates, myremoved, commitmessage)

		# When files are removed and re-added, the cvs server will put /Attic/
		# inside the $Header path. This code detects the problem and corrects it
		# so that the Manifest will generate correctly. See bug #169500.
		# Use binary mode in order to avoid potential character encoding issues.
		self.clear_attic(myheaders)

		if self.scanner.repolevel == 1:
			utilities.repoman_sez(
				"\"You're rather crazy... "
				"doing the entire repository.\"\n")

		if self.vcs_settings.vcs in ('cvs', 'svn') and (myupdates or myremoved):
			for x in sorted(vcs_files_to_cps(
				chain(myupdates, myremoved, mymanifests),
				self.scanner.repolevel, self.scanner.reposplit, self.scanner.categories)):
				self.repoman_settings["O"] = os.path.join(self.repo_settings.repodir, x)
				digestgen(mysettings=self.repoman_settings, myportdb=self.repo_settings.portdb)

		elif broken_changelog_manifests:
			for x in broken_changelog_manifests:
				self.repoman_settings["O"] = os.path.join(self.repo_settings.repodir, x)
#.........这里部分代码省略.........

def unmerge(root_config, myopts, unmerge_action,
	unmerge_files, ldpath_mtimes, autoclean=0,
	clean_world=1, clean_delay=1, ordered=0, raise_on_error=0,
	scheduler=None, writemsg_level=portage.util.writemsg_level):

	if clean_world:
		clean_world = myopts.get('--deselect') != 'n'
	quiet = "--quiet" in myopts
	enter_invalid = '--ask-enter-invalid' in myopts
	settings = root_config.settings
	sets = root_config.sets
	vartree = root_config.trees["vartree"]
	candidate_catpkgs=[]
	global_unmerge=0
	xterm_titles = "notitles" not in settings.features
	out = portage.output.EOutput()
	pkg_cache = {}
	db_keys = list(vartree.dbapi._aux_cache_keys)

	def _pkg(cpv):
		pkg = pkg_cache.get(cpv)
		if pkg is None:
			pkg = Package(built=True, cpv=cpv, installed=True,
				metadata=zip(db_keys, vartree.dbapi.aux_get(cpv, db_keys)),
				operation="uninstall", root_config=root_config,
				type_name="installed")
			pkg_cache[cpv] = pkg
		return pkg

	vdb_path = os.path.join(settings["ROOT"], portage.VDB_PATH)
	try:
		# At least the parent needs to exist for the lock file.
		portage.util.ensure_dirs(vdb_path)
	except portage.exception.PortageException:
		pass
	vdb_lock = None
	try:
		if os.access(vdb_path, os.W_OK):
			vdb_lock = portage.locks.lockdir(vdb_path)
		realsyslist = sets["system"].getAtoms()
		syslist = []
		for x in realsyslist:
			mycp = portage.dep_getkey(x)
			if mycp in settings.getvirtuals():
				providers = []
				for provider in settings.getvirtuals()[mycp]:
					if vartree.dbapi.match(provider):
						providers.append(provider)
				if len(providers) == 1:
					syslist.extend(providers)
			else:
				syslist.append(mycp)
	
		mysettings = portage.config(clone=settings)
	
		if not unmerge_files:
			if unmerge_action == "unmerge":
				print()
				print(bold("emerge unmerge") + " can only be used with specific package names")
				print()
				return 0
			else:
				global_unmerge = 1
	
		localtree = vartree
		# process all arguments and add all
		# valid db entries to candidate_catpkgs
		if global_unmerge:
			if not unmerge_files:
				candidate_catpkgs.extend(vartree.dbapi.cp_all())
		else:
			#we've got command-line arguments
			if not unmerge_files:
				print("\nNo packages to unmerge have been provided.\n")
				return 0
			for x in unmerge_files:
				arg_parts = x.split('/')
				if x[0] not in [".","/"] and \
					arg_parts[-1][-7:] != ".ebuild":
					#possible cat/pkg or dep; treat as such
					candidate_catpkgs.append(x)
				elif unmerge_action in ["prune","clean"]:
					print("\n!!! Prune and clean do not accept individual" + \
						" ebuilds as arguments;\n    skipping.\n")
					continue
				else:
					# it appears that the user is specifying an installed
					# ebuild and we're in "unmerge" mode, so it's ok.
					if not os.path.exists(x):
						print("\n!!! The path '"+x+"' doesn't exist.\n")
						return 0
	
					absx   = os.path.abspath(x)
					sp_absx = absx.split("/")
					if sp_absx[-1][-7:] == ".ebuild":
						del sp_absx[-1]
						absx = "/".join(sp_absx)
	
					sp_absx_len = len(sp_absx)
	
#.........这里部分代码省略.........

def _unmerge_display(root_config, myopts, unmerge_action,
	unmerge_files, clean_delay=1, ordered=0,
	writemsg_level=portage.util.writemsg_level):
	"""
	Returns a tuple of (returncode, pkgmap) where returncode is
	os.EX_OK if no errors occur, and 1 otherwise.
	"""

	quiet = "--quiet" in myopts
	settings = root_config.settings
	sets = root_config.sets
	vartree = root_config.trees["vartree"]
	candidate_catpkgs=[]
	global_unmerge=0
	out = portage.output.EOutput()
	pkg_cache = {}
	db_keys = list(vartree.dbapi._aux_cache_keys)

	def _pkg(cpv):
		pkg = pkg_cache.get(cpv)
		if pkg is None:
			pkg = Package(built=True, cpv=cpv, installed=True,
				metadata=zip(db_keys, vartree.dbapi.aux_get(cpv, db_keys)),
				operation="uninstall", root_config=root_config,
				type_name="installed")
			pkg_cache[cpv] = pkg
		return pkg

	vdb_path = os.path.join(settings["EROOT"], portage.VDB_PATH)
	try:
		# At least the parent needs to exist for the lock file.
		portage.util.ensure_dirs(vdb_path)
	except portage.exception.PortageException:
		pass
	vdb_lock = None
	try:
		if os.access(vdb_path, os.W_OK):
			vartree.dbapi.lock()
			vdb_lock = True

		realsyslist = []
		sys_virt_map = {}
		for x in sets["system"].getAtoms():
			for atom in expand_new_virt(vartree.dbapi, x):
				if not atom.blocker:
					realsyslist.append(atom)
					if atom.cp != x.cp:
						sys_virt_map[atom.cp] = x.cp

		syslist = []
		for x in realsyslist:
			mycp = x.cp
			# Since Gentoo stopped using old-style virtuals in
			# 2011, typically it's possible to avoid getvirtuals()
			# calls entirely. It will not be triggered here by
			# new-style virtuals since those are expanded to
			# non-virtual atoms above by expand_new_virt().
			if mycp.startswith("virtual/") and \
				mycp in settings.getvirtuals():
				providers = []
				for provider in settings.getvirtuals()[mycp]:
					if vartree.dbapi.match(provider):
						providers.append(provider)
				if len(providers) == 1:
					syslist.extend(providers)
			else:
				syslist.append(mycp)
		syslist = frozenset(syslist)

		if not unmerge_files:
			if unmerge_action in ["rage-clean", "unmerge"]:
				print()
				print(bold("emerge %s" % unmerge_action) +
						" can only be used with specific package names")
				print()
				return 1, {}
			else:
				global_unmerge = 1

		localtree = vartree
		# process all arguments and add all
		# valid db entries to candidate_catpkgs
		if global_unmerge:
			if not unmerge_files:
				candidate_catpkgs.extend(vartree.dbapi.cp_all())
		else:
			#we've got command-line arguments
			if not unmerge_files:
				print("\nNo packages to %s have been provided.\n" %
						unmerge_action)
				return 1, {}
			for x in unmerge_files:
				arg_parts = x.split('/')
				if x[0] not in [".","/"] and \
					arg_parts[-1][-7:] != ".ebuild":
					#possible cat/pkg or dep; treat as such
					candidate_catpkgs.append(x)
				elif unmerge_action in ["prune","clean"]:
					print("\n!!! Prune and clean do not accept individual" + \
						" ebuilds as arguments;\n    skipping.\n")
#.........这里部分代码省略.........

	def _aux_get_error(self, cpv):
		portage.writemsg("emerge: search: "
			"aux_get('%s') failed, skipping\n" % cpv,
			noiselevel=-1)

	def findInstalledBlockers(self, new_pkg, acquire_lock=0):
		blocker_cache = BlockerCache(self._vartree.root, self._vartree.dbapi)
		dep_keys = ["DEPEND", "RDEPEND", "PDEPEND"]
		settings = self._vartree.settings
		stale_cache = set(blocker_cache)
		fake_vartree = self._get_fake_vartree(acquire_lock=acquire_lock)
		dep_check_trees = self._dep_check_trees
		vardb = fake_vartree.dbapi
		installed_pkgs = list(vardb)

		for inst_pkg in installed_pkgs:
			stale_cache.discard(inst_pkg.cpv)
			cached_blockers = blocker_cache.get(inst_pkg.cpv)
			if cached_blockers is not None and \
				cached_blockers.counter != long(inst_pkg.metadata["COUNTER"]):
				cached_blockers = None
			if cached_blockers is not None:
				blocker_atoms = cached_blockers.atoms
			else:
				# Use aux_get() to trigger FakeVartree global
				# updates on *DEPEND when appropriate.
				depstr = " ".join(vardb.aux_get(inst_pkg.cpv, dep_keys))
				success, atoms = portage.dep_check(depstr,
					vardb, settings, myuse=inst_pkg.use.enabled,
					trees=dep_check_trees, myroot=inst_pkg.root)
				if not success:
					pkg_location = os.path.join(inst_pkg.root,
						portage.VDB_PATH, inst_pkg.category, inst_pkg.pf)
					portage.writemsg("!!! %s/*DEPEND: %s\n" % \
						(pkg_location, atoms), noiselevel=-1)
					continue

				blocker_atoms = [atom for atom in atoms \
					if atom.startswith("!")]
				blocker_atoms.sort()
				counter = long(inst_pkg.metadata["COUNTER"])
				blocker_cache[inst_pkg.cpv] = \
					blocker_cache.BlockerData(counter, blocker_atoms)
		for cpv in stale_cache:
			del blocker_cache[cpv]
		blocker_cache.flush()

		blocker_parents = digraph()
		blocker_atoms = []
		for pkg in installed_pkgs:
			for blocker_atom in blocker_cache[pkg.cpv].atoms:
				blocker_atom = blocker_atom.lstrip("!")
				blocker_atoms.append(blocker_atom)
				blocker_parents.add(blocker_atom, pkg)

		blocker_atoms = InternalPackageSet(initial_atoms=blocker_atoms)
		blocking_pkgs = set()
		for atom in blocker_atoms.iterAtomsForPackage(new_pkg):
			blocking_pkgs.update(blocker_parents.parent_nodes(atom))

		# Check for blockers in the other direction.
		depstr = " ".join(new_pkg.metadata[k] for k in dep_keys)
		success, atoms = portage.dep_check(depstr,
			vardb, settings, myuse=new_pkg.use.enabled,
			trees=dep_check_trees, myroot=new_pkg.root)
		if not success:
			# We should never get this far with invalid deps.
			show_invalid_depstring_notice(new_pkg, depstr, atoms)
			assert False

		blocker_atoms = [atom.lstrip("!") for atom in atoms \
			if atom[:1] == "!"]
		if blocker_atoms:
			blocker_atoms = InternalPackageSet(initial_atoms=blocker_atoms)
			for inst_pkg in installed_pkgs:
				try:
					next(blocker_atoms.iterAtomsForPackage(inst_pkg))
				except (portage.exception.InvalidDependString, StopIteration):
					continue
				blocking_pkgs.add(inst_pkg)

		return blocking_pkgs