Add support for the following attributes in layout.conf to allow more
precise configuration of inheritance of settings from repositories:
  eclass-masters
  package.mask-masters
  use.aliases-masters
  use.force-masters
  use.mask-masters
diff --git a/man/portage.5 b/man/portage.5
index 0aac569..5090529 100644
--- a/man/portage.5
+++ b/man/portage.5
@@ -800,7 +800,9 @@
 Specifies names of attributes, which should be forcefully respected by
 \fBegencache\fR(1), \fBemirrordist\fR(1) and \fBrepoman\fR(1).
 .br
-Valid values: aliases, eclass\-overrides, masters
+Valid values: aliases, eclass\-masters, eclass\-overrides, masters,
+package.mask\-masters, use.aliases\-masters, use.force\-masters,
+use.mask\-masters
 .RE
 
 .I Attributes supported in sections of repositories:
@@ -834,21 +836,24 @@
 Specifies names of attributes, which should be forcefully respected by
 \fBegencache\fR(1), \fBemirrordist\fR(1) and \fBrepoman\fR(1).
 .br
-Valid values: aliases, eclass\-overrides, masters
+Valid values: aliases, eclass\-masters, eclass\-overrides, masters,
+package.mask\-masters, use.aliases\-masters, use.force\-masters,
+use.mask\-masters
 .TP
 .B location
 Specifies location of given repository.
 .TP
-.B masters
-Specifies master repositories of given repository.
+.B masters, eclass\-masters, package.mask\-masters, use.aliases\-masters, use.force\-masters, use.mask\-masters
+Specifies master repositories of given repository. See documentation of
+\fBlayout.conf\fR file for more details.
 .br
-Setting this attribute is generally not recommended since resulting changes
+Setting these attribute is generally not recommended since resulting changes
 in eclass inheritance may trigger performance issues due to invalidation
 of metadata cache.
 .br
-When 'force = masters' attribute is not set, \fBegencache\fR(1),
-\fBemirrordist\fR(1) and \fBrepoman\fR(1) ignore this attribute,
-since operations performed by these tools are inherently
+When 'force = ${attribute}' (e.g. 'force = masters') attribute is not set,
+\fBegencache\fR(1), \fBemirrordist\fR(1) and \fBrepoman\fR(1) ignore given
+attribute, since operations performed by these tools are inherently
 \fBnot\fR \fIsite\-specific\fR.
 .TP
 .B priority
@@ -986,9 +991,10 @@
 \fB/etc/portage/repos.conf\fR.
 Settings in \fBrepos.conf\fR take precedence over settings in
 \fBlayout.conf\fR, except tools such as \fBrepoman\fR(1) and \fBegencache\fR(1)
-ignore "aliases", "eclass-overrides" and "masters" attributes set in
-\fBrepos.conf\fR since their operations are inherently \fBnot\fR
-\fIsite\-specific\fR.
+ignore "aliases", "eclass\-masters", "eclass\-overrides", "masters",
+"package.mask\-masters", "use.aliases\-masters", "use.force\-masters" and
+"use.mask\-masters" attributes set in \fBrepos.conf\fR since their operations
+are inherently \fBnot\fR \fIsite\-specific\fR.
 
 .I Format:
 .nf
@@ -996,7 +1002,7 @@
 \- attributes are specified in "${attribute} = ${value}" format
 .fi
 
-.I Supported attributes.
+.I Supported attributes:
 .RS
 .RS
 .TP
@@ -1009,6 +1015,14 @@
 .BR eapis\-deprecated
 List of EAPIs which are allowed but generate warnings when used.
 .TP
+.BR eclass\-masters
+Names of repositories wherefrom eclasses can be inherited.
+.br
+This attribute overrides \fBmasters\fR attribute and should be used only when
+there is a need to set this attribute to a different value than value of
+\fBmasters\fR attribute. See documentation of \fBmasters\fR attribute for more
+details.
+.TP
 .BR masters
 Names of repositories which satisfy dependencies on eclasses and from which
 settings specified in various repository\-level files (\fBpackage.mask\fR,
@@ -1018,6 +1032,15 @@
 listed toward the right of the \fBmasters\fR list take precedence over those
 listed toward the left of the list.
 .TP
+.BR package.mask-masters
+Names of repositories wherefrom settings specified in repository\-level
+\fBpackage.mask\fR files are inherited.
+.br
+This attribute overrides \fBmasters\fR attribute and should be used only when
+there is a need to set this attribute to a different value than value of
+\fBmasters\fR attribute. See documentation of \fBmasters\fR attribute for more
+details.
+.TP
 .BR repo\-name " = <value of profiles/repo_name>"
 The name of this repository (overrides profiles/repo_name if it exists).
 .TP
@@ -1030,6 +1053,35 @@
 .BR thin\-manifests " = [true|" false "]"
 Boolean value whether Manifest files contain only DIST entries.
 .TP
+.BR use.aliases\-masters
+Names of repositories wherefrom settings specified in repository\-level
+\fBpackage.use.aliases\fR and \fBuse.aliases\fR files are inherited.
+.br
+This attribute overrides \fBmasters\fR attribute and should be used only when
+there is a need to set this attribute to a different value than value of
+\fBmasters\fR attribute. See documentation of \fBmasters\fR attribute for more
+details.
+.TP
+.BR use.force\-masters
+Names of repositories wherefrom settings specified in repository\-level
+\fBpackage.use.force\fR, \fBpackage.use.stable.force\fR, \fBuse.force\fR and
+\fBuse.stable.force\fR files are inherited.
+.br
+This attribute overrides \fBmasters\fR attribute and should be used only when
+there is a need to set this attribute to a different value than value of
+\fBmasters\fR attribute. See documentation of \fBmasters\fR attribute for more
+details.
+.TP
+.BR use.mask\-masters
+Names of repositories wherefrom settings specified in repository\-level
+\fBpackage.use.mask\fR, \fBpackage.use.stable.mask\fR, \fuse.mask\fR and
+\fBuse.stable.mask\fR files are inherited.
+.br
+This attribute overrides \fBmasters\fR attribute and should be used only when
+there is a need to set this attribute to a different value than value of
+\fBmasters\fR attribute. See documentation of \fBmasters\fR attribute for more
+details.
+.TP
 .BR use\-manifests " = [" strict "|true|false]"
 How Manifest files get used.  Possible values are "strict" (require an entry
 for every file), "true" (if an entry exists for a file, enforce it), or "false"
diff --git a/pym/portage/package/ebuild/_config/MaskManager.py b/pym/portage/package/ebuild/_config/MaskManager.py
index aeb04d7..4358b63 100644
--- a/pym/portage/package/ebuild/_config/MaskManager.py
+++ b/pym/portage/package/ebuild/_config/MaskManager.py
@@ -1,4 +1,4 @@
-# Copyright 2010-2013 Gentoo Foundation
+# Copyright 2010-2014 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 __all__ = (
@@ -58,7 +58,11 @@
 			removals = frozenset(line[0][1:] for line in repo_lines
 				if line[0][:1] == "-")
 			matched_removals = set()
-			for master in repo.masters:
+			if repo.package_mask_masters is not None:
+				masters = repo.package_mask_masters
+			else:
+				masters = repo.masters
+			for master in masters:
 				master_lines = grab_pmask(master.location, master)
 				for line in master_lines:
 					if line[0] in removals:
@@ -75,7 +79,7 @@
 			# It's safe to warn for unmatched removal if masters have not
 			# been overridden by the user, which is guaranteed when
 			# user_config is false (when called by repoman).
-			if repo.masters:
+			if masters:
 				unmatched_removals = removals.difference(matched_removals)
 				if unmatched_removals and not user_config:
 					source_file = os.path.join(repo.location,
diff --git a/pym/portage/package/ebuild/_config/UseManager.py b/pym/portage/package/ebuild/_config/UseManager.py
index 0d00810..a65e5bd 100644
--- a/pym/portage/package/ebuild/_config/UseManager.py
+++ b/pym/portage/package/ebuild/_config/UseManager.py
@@ -1,4 +1,4 @@
-# Copyright 2010-2013 Gentoo Foundation
+# Copyright 2010-2014 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 __all__ = (
@@ -312,8 +312,11 @@
 		if hasattr(pkg, "repo") and pkg.repo != Package.UNKNOWN_REPO:
 			repos = []
 			try:
-				repos.extend(repo.name for repo in
-					self.repositories[pkg.repo].masters)
+				if self.repositories[pkg.repo].use_mask_masters is not None:
+					masters = self.repositories[pkg.repo].use_mask_masters
+				else:
+					masters = self.repositories[pkg.repo].masters
+				repos.extend(repo.name for repo in masters)
 			except KeyError:
 				pass
 			repos.append(pkg.repo)
@@ -372,8 +375,11 @@
 		if hasattr(pkg, "repo") and pkg.repo != Package.UNKNOWN_REPO:
 			repos = []
 			try:
-				repos.extend(repo.name for repo in
-					self.repositories[pkg.repo].masters)
+				if self.repositories[pkg.repo].use_force_masters is not None:
+					masters = self.repositories[pkg.repo].use_force_masters
+				else:
+					masters = self.repositories[pkg.repo].masters
+				repos.extend(repo.name for repo in masters)
 			except KeyError:
 				pass
 			repos.append(pkg.repo)
@@ -428,8 +434,11 @@
 		if hasattr(pkg, "repo") and pkg.repo != Package.UNKNOWN_REPO:
 			repos = []
 			try:
-				repos.extend(repo.name for repo in
-					self.repositories[pkg.repo].masters)
+				if self.repositories[pkg.repo].use_aliases_masters is not None:
+					masters = self.repositories[pkg.repo].use_aliases_masters
+				else:
+					masters = self.repositories[pkg.repo].masters
+				repos.extend(repo.name for repo in masters)
 			except KeyError:
 				pass
 			repos.append(pkg.repo)
diff --git a/pym/portage/package/ebuild/getmaskingreason.py b/pym/portage/package/ebuild/getmaskingreason.py
index 70a6bf2..673b40a 100644
--- a/pym/portage/package/ebuild/getmaskingreason.py
+++ b/pym/portage/package/ebuild/getmaskingreason.py
@@ -1,4 +1,4 @@
-# Copyright 2010-2013 Gentoo Foundation
+# Copyright 2010-2014 Gentoo Foundation
 # Distributed under the terms of the GNU General Public License v2
 
 __all__ = ['getmaskingreason']
@@ -70,7 +70,11 @@
 
 	locations = []
 	if pkg.repo in settings.repositories:
-		for repo in settings.repositories[pkg.repo].masters + (settings.repositories[pkg.repo],):
+		if settings.repositories[pkg.repo].package_mask_masters is not None:
+			masters = settings.repositories[pkg.repo].package_mask_masters
+		else:
+			masters = settings.repositories[pkg.repo].masters
+		for repo in masters + (settings.repositories[pkg.repo],):
 			locations.append(os.path.join(repo.location, "profiles"))
 	locations.extend(settings.profiles)
 	locations.append(os.path.join(settings["PORTAGE_CONFIGROOT"],
diff --git a/pym/portage/repository/config.py b/pym/portage/repository/config.py
index 71b75fb..b7ee34f 100644
--- a/pym/portage/repository/config.py
+++ b/pym/portage/repository/config.py
@@ -44,6 +44,9 @@
 _portage1_profiles_allow_directories = frozenset(
 	["portage-1-compat", "portage-1", 'portage-2'])
 
+_masters_attributes = dict((x, x.replace("-", "_").replace(".", "_")) for x in
+	("masters", "eclass-masters", "package.mask-masters", "use.aliases-masters", "use.force-masters", "use.mask-masters"))
+
 _repo_name_sub_re = re.compile(r'[^\w-]')
 
 def _gen_valid_repo(name):
@@ -80,11 +83,12 @@
 		'cache_formats', 'create_manifest', 'disable_manifest', 'eapi',
 		'eclass_db', 'eclass_locations', 'eclass_overrides',
 		'find_invalid_path_char', 'force', 'format', 'local_config', 'location',
-		'main_repo', 'manifest_hashes', 'masters', 'missing_repo_name',
+		'main_repo', 'manifest_hashes', 'missing_repo_name',
 		'name', 'portage1_profiles', 'portage1_profiles_compat', 'priority',
 		'profile_formats', 'sign_commit', 'sign_manifest', 'sync_cvs_repo',
 		'sync_type', 'sync_uri', 'thin_manifest', 'update_changelog',
-		'user_location', '_eapis_banned', '_eapis_deprecated', '_masters_orig')
+		'user_location', '_eapis_banned', '_eapis_deprecated', '_masters_orig') + \
+		tuple(_masters_attributes.values())
 
 	def __init__(self, name, repo_opts, local_config=True):
 		"""Build a RepoConfig with options in repo_opts
@@ -106,7 +110,6 @@
 				aliases = tuple(aliases.split())
 		else:
 			aliases = None
-
 		self.aliases = aliases
 
 		if local_config or 'eclass-overrides' in force:
@@ -115,21 +118,21 @@
 				eclass_overrides = tuple(eclass_overrides.split())
 		else:
 			eclass_overrides = None
-
 		self.eclass_overrides = eclass_overrides
+
 		# Eclass databases and locations are computed later.
 		self.eclass_db = None
 		self.eclass_locations = None
 
-		if local_config or 'masters' in force:
-			# Masters from repos.conf override layout.conf.
-			masters = repo_opts.get('masters')
-			if masters is not None:
-				masters = tuple(masters.split())
-		else:
-			masters = None
-
-		self.masters = masters
+		for attr, underscorized_attr in _masters_attributes.items():
+			if local_config or attr in force:
+				# Masters from repos.conf override layout.conf.
+				masters = repo_opts.get(attr)
+				if masters is not None:
+					masters = tuple(masters.split())
+			else:
+				masters = None
+			setattr(self, underscorized_attr, masters)
 
 		#The main-repo key makes only sense for the 'DEFAULT' section.
 		self.main_repo = repo_opts.get('main-repo')
@@ -216,8 +219,9 @@
 
 			# layout.conf masters may be overridden here if we have a masters
 			# setting from the user's repos.conf
-			if self.masters is None:
-				self.masters = layout_data['masters']
+			for attr, underscorized_attr in _masters_attributes.items():
+				if getattr(self, underscorized_attr) is None:
+					setattr(self, underscorized_attr, layout_data[attr])
 
 			if (local_config or 'aliases' in force) and layout_data['aliases']:
 				aliases = self.aliases
@@ -370,8 +374,10 @@
 			repo_msg.append(indent + "sync-type: " + self.sync_type)
 		if self.sync_uri:
 			repo_msg.append(indent + "sync-uri: " + self.sync_uri)
-		if self.masters:
-			repo_msg.append(indent + "masters: " + " ".join(master.name for master in self.masters))
+		for attr, underscorized_attr in _masters_attributes.items():
+			masters = getattr(self, underscorized_attr)
+			if masters:
+				repo_msg.append(indent + attr + ": " + " ".join(master.name for master in masters))
 		if self.priority is not None:
 			repo_msg.append(indent + "priority: " + str(self.priority))
 		if self.aliases:
@@ -743,36 +749,43 @@
 		for repo_name, repo in prepos.items():
 			if repo_name == "DEFAULT":
 				continue
-			if repo.masters is None:
-				if self.mainRepo() and repo_name != self.mainRepo().name:
-					repo.masters = self.mainRepo(),
+			for attr, underscorized_attr in _masters_attributes.items():
+				masters = getattr(repo, underscorized_attr)
+				if masters is None:
+					if attr == 'masters':
+						if self.mainRepo() and repo_name != self.mainRepo().name:
+							setattr(repo, underscorized_attr, (self.mainRepo(),))
+						else:
+							setattr(repo, underscorized_attr, ())
 				else:
-					repo.masters = ()
-			else:
-				if repo.masters and isinstance(repo.masters[0], RepoConfig):
-					# This one has already been processed
-					# because it has an alias.
-					continue
-				master_repos = []
-				for master_name in repo.masters:
-					if master_name not in prepos:
-						layout_filename = os.path.join(repo.user_location,
-							"metadata", "layout.conf")
-						writemsg_level(_("Unavailable repository '%s' " \
-							"referenced by masters entry in '%s'\n") % \
-							(master_name, layout_filename),
-							level=logging.ERROR, noiselevel=-1)
-					else:
-						master_repos.append(prepos[master_name])
-				repo.masters = tuple(master_repos)
+					if masters and isinstance(masters[0], RepoConfig):
+						# This one has already been processed
+						# because it has an alias.
+						continue
+					master_repos = []
+					for master_name in masters:
+						if master_name not in prepos:
+							layout_filename = os.path.join(repo.user_location,
+								"metadata", "layout.conf")
+							writemsg_level(_("Unavailable repository '%s' " \
+								"referenced by %s attribute in '%s'\n") % \
+								(master_name, attr, layout_filename),
+								level=logging.ERROR, noiselevel=-1)
+						else:
+							master_repos.append(prepos[master_name])
+					setattr(repo, underscorized_attr, tuple(master_repos))
 
 		#The 'eclass_overrides' key currently contains repo names. Replace them with the matching repo paths.
 		for repo_name, repo in prepos.items():
 			if repo_name == "DEFAULT":
 				continue
 
+			if repo.eclass_masters is not None:
+				masters = repo.eclass_masters
+			else:
+				masters = repo.masters
 			eclass_locations = []
-			eclass_locations.extend(master_repo.location for master_repo in repo.masters)
+			eclass_locations.extend(master_repo.location for master_repo in masters)
 			# Only append the current repo to eclass_locations if it's not
 			# there already. This allows masters to have more control over
 			# eclass override order, which may be useful for scenarios in
@@ -921,23 +934,24 @@
 		return repo_name in self.prepos
 
 	def config_string(self):
-		str_or_int_keys = ("format", "location", "main_repo", "priority", "sync_cvs_repo", "sync_type", "sync_uri")
-		str_tuple_keys = ("aliases", "eclass_overrides", "force")
-		repo_config_tuple_keys = ("masters",)
-		keys = str_or_int_keys + str_tuple_keys + repo_config_tuple_keys
+		str_or_int_attrs = ("format", "location", "main-repo", "priority", "sync-cvs-repo", "sync-type", "sync-uri")
+		str_tuple_attrs = ("aliases", "eclass-overrides", "force")
+		repo_config_tuple_attrs = tuple(_masters_attributes.keys())
+		attrs = str_or_int_attrs + str_tuple_attrs + repo_config_tuple_attrs
 		config_string = ""
 		for repo_name, repo in sorted(self.prepos.items()):
 			config_string += "\n[%s]\n" % repo_name
-			for key in sorted(keys):
-				if key == "main_repo" and repo_name != "DEFAULT":
+			for attr in sorted(attrs):
+				underscorized_attr = attr.replace("-", "_").replace(".", "_")
+				if attr == "main-repo" and repo_name != "DEFAULT":
 					continue
-				if getattr(repo, key) is not None:
-					if key in str_or_int_keys:
-						config_string += "%s = %s\n" % (key.replace("_", "-"), getattr(repo, key))
-					elif key in str_tuple_keys:
-						config_string += "%s = %s\n" % (key.replace("_", "-"), " ".join(getattr(repo, key)))
-					elif key in repo_config_tuple_keys:
-						config_string += "%s = %s\n" % (key.replace("_", "-"), " ".join(x.name for x in getattr(repo, key)))
+				if getattr(repo, underscorized_attr) is not None:
+					if attr in str_or_int_attrs:
+						config_string += "%s = %s\n" % (attr, getattr(repo, underscorized_attr))
+					elif attr in str_tuple_attrs:
+						config_string += "%s = %s\n" % (attr, " ".join(getattr(repo, underscorized_attr)))
+					elif attr in repo_config_tuple_attrs:
+						config_string += "%s = %s\n" % (attr, " ".join(x.name for x in getattr(repo, underscorized_attr)))
 		return config_string.lstrip("\n")
 
 def load_repository_config(settings, extra_files=None):
@@ -971,15 +985,17 @@
 
 	data = {}
 
-	# None indicates abscence of a masters setting, which later code uses
+	# None indicates absence of a masters setting, which later code uses
 	# to trigger a backward compatibility fallback that sets an implicit
 	# master. In order to avoid this fallback behavior, layout.conf can
 	# explicitly set masters to an empty value, which will result in an
 	# empty tuple here instead of None.
-	masters = layout_data.get('masters')
-	if masters is not None:
-		masters = tuple(masters.split())
-	data['masters'] = masters
+	for attr in _masters_attributes.keys():
+		masters = layout_data.get(attr)
+		if masters is not None:
+			masters = tuple(masters.split())
+		data[attr] = masters
+
 	data['aliases'] = tuple(layout_data.get('aliases', '').split())
 
 	data['allow-provide-virtual'] = \