pym/portage/__init__.py

# portage.py -- core Portage functionality
# Copyright 1998-2004 Gentoo Foundation
# Distributed under the terms of the GNU General Public License v2
# $Id$


VERSION="$Rev$"[6:-2] + "-svn"

# ===========================================================================
# START OF IMPORTS -- START OF IMPORTS -- START OF IMPORTS -- START OF IMPORT
# ===========================================================================

try:
	import sys
	import copy
	import errno
	import os
	import re
	import shutil
	import time
	try:
		import cPickle
	except ImportError:
		import pickle as cPickle

	import stat
	import commands
	from time import sleep
	from random import shuffle
	import UserDict
	from itertools import chain, izip
	import platform
	import warnings
except ImportError, e:
	sys.stderr.write("\n\n")
	sys.stderr.write("!!! Failed to complete python imports. These are internal modules for\n")
	sys.stderr.write("!!! python and failure here indicates that you have a problem with python\n")
	sys.stderr.write("!!! itself and thus portage is not able to continue processing.\n\n")

	sys.stderr.write("!!! You might consider starting python with verbose flags to see what has\n")
	sys.stderr.write("!!! gone wrong. Here is the information we got for this exception:\n")
	sys.stderr.write("    "+str(e)+"\n\n");
	raise

bsd_chflags = None
if platform.system() in ["FreeBSD"]:
	def bsd_chflags():
		pass
	def _chflags(path, flags, opts=""):
		cmd = "chflags %s %o '%s'" % (opts, flags, path)
		status, output = commands.getstatusoutput(cmd)
		if os.WIFEXITED(status) and os.WEXITSTATUS(status) == os.EX_OK:
			return
		# Try to generate an ENOENT error if appropriate.
		if "h" in opts:
			os.lstat(path)
		else:
			os.stat(path)
		# Make sure the binary exists.
		if not portage.process.find_binary("chflags"):
			raise portage.exception.CommandNotFound("chflags")
		# Now we're not sure exactly why it failed or what
		# the real errno was, so just report EPERM.
		e = OSError(errno.EPERM, output)
		e.errno = errno.EPERM
		e.filename = path
		e.message = output
		raise e
	def _lchflags(path, flags):
		return _chflags(path, flags, opts="-h")
	bsd_chflags.chflags = _chflags
	bsd_chflags.lchflags = _lchflags

try:
	from portage.cache.cache_errors import CacheError
	import portage.cvstree
	import portage.xpak
	import portage.getbinpkg
	import portage.dep
	from portage.dep import dep_getcpv, dep_getkey, get_operator, \
		isjustname, isspecific, isvalidatom, \
		match_from_list, match_to_list, best_match_to_list

	# XXX: This needs to get cleaned up.
	import portage.output
	from portage.output import bold, colorize, green, red, yellow

	import portage.const
	from portage.const import VDB_PATH, PRIVATE_PATH, CACHE_PATH, DEPCACHE_PATH, \
		USER_CONFIG_PATH, MODULES_FILE_PATH, CUSTOM_PROFILE_PATH, PORTAGE_BASE_PATH, \
		PORTAGE_BIN_PATH, PORTAGE_PYM_PATH, PROFILE_PATH, LOCALE_DATA_PATH, \
		EBUILD_SH_BINARY, SANDBOX_BINARY, BASH_BINARY, \
		MOVE_BINARY, PRELINK_BINARY, WORLD_FILE, MAKE_CONF_FILE, MAKE_DEFAULTS_FILE, \
		DEPRECATED_PROFILE_FILE, USER_VIRTUALS_FILE, EBUILD_SH_ENV_FILE, \
		INVALID_ENV_FILE, CUSTOM_MIRRORS_FILE, CONFIG_MEMORY_FILE,\
		INCREMENTALS, EAPI, MISC_SH_BINARY, REPO_NAME_LOC, REPO_NAME_FILE

	from portage.data import ostype, lchown, userland, secpass, uid, wheelgid, \
	                         portage_uid, portage_gid, userpriv_groups
	from portage.manifest import Manifest

	import portage.util
	from portage.util import atomic_ofstream, apply_secpass_permissions, apply_recursive_permissions, \
		dump_traceback, getconfig, grabdict, grabdict_package, grabfile, grabfile_package, \
		map_dictlist_vals, new_protect_filename, normalize_path, \
		pickle_read, pickle_write, stack_dictlist, stack_dicts, stack_lists, \
		unique_array, varexpand, writedict, writemsg, writemsg_stdout, write_atomic
	import portage.exception
	import portage.gpg
	import portage.locks
	import portage.process
	from portage.process import atexit_register, run_exitfuncs
	from portage.locks import unlockfile,unlockdir,lockfile,lockdir
	import portage.checksum
	from portage.checksum import perform_md5,perform_checksum,prelink_capable
	import portage.eclass_cache
	from portage.localization import _
	from portage.update import dep_transform, fixdbentries, grab_updates, \
		parse_updates, update_config_files, update_dbentries

	# Need these functions directly in portage namespace to not break every external tool in existence
	from portage.versions import best, catpkgsplit, catsplit, pkgcmp, \
		pkgsplit, vercmp, ververify

	# endversion and endversion_keys are for backward compatibility only.
	from portage.versions import endversion_keys
	from portage.versions import suffix_value as endversion

except ImportError, e:
	sys.stderr.write("\n\n")
	sys.stderr.write("!!! Failed to complete portage imports. There are internal modules for\n")
	sys.stderr.write("!!! portage and failure here indicates that you have a problem with your\n")
	sys.stderr.write("!!! installation of portage. Please try a rescue portage located in the\n")
	sys.stderr.write("!!! portage tree under '/usr/portage/sys-apps/portage/files/' (default).\n")
	sys.stderr.write("!!! There is a README.RESCUE file that details the steps required to perform\n")
	sys.stderr.write("!!! a recovery of portage.\n")
	sys.stderr.write("    "+str(e)+"\n\n")
	raise


try:
	import portage.selinux as selinux
except OSError, e:
	writemsg("!!! SELinux not loaded: %s\n" % str(e), noiselevel=-1)
	del e
except ImportError:
	pass

# ===========================================================================
# END OF IMPORTS -- END OF IMPORTS -- END OF IMPORTS -- END OF IMPORTS -- END
# ===========================================================================


def load_mod(name):
	modname = ".".join(name.split(".")[:-1])
	mod = __import__(modname)
	components = name.split('.')
	for comp in components[1:]:
		mod = getattr(mod, comp)
	return mod

def best_from_dict(key, top_dict, key_order, EmptyOnError=1, FullCopy=1, AllowEmpty=1):
	for x in key_order:
		if x in top_dict and key in top_dict[x]:
			if FullCopy:
				return copy.deepcopy(top_dict[x][key])
			else:
				return top_dict[x][key]
	if EmptyOnError:
		return ""
	else:
		raise KeyError("Key not found in list; '%s'" % key)

def getcwd():
	"this fixes situations where the current directory doesn't exist"
	try:
		return os.getcwd()
	except OSError: #dir doesn't exist
		os.chdir("/")
		return "/"
getcwd()

def abssymlink(symlink):
	"This reads symlinks, resolving the relative symlinks, and returning the absolute."
	mylink=os.readlink(symlink)
	if mylink[0] != '/':
		mydir=os.path.dirname(symlink)
		mylink=mydir+"/"+mylink
	return os.path.normpath(mylink)

dircache = {}
cacheHit=0
cacheMiss=0
cacheStale=0
def cacheddir(my_original_path, ignorecvs, ignorelist, EmptyOnError, followSymlinks=True):
	global cacheHit,cacheMiss,cacheStale
	mypath = normalize_path(my_original_path)
	if mypath in dircache:
		cacheHit += 1
		cached_mtime, list, ftype = dircache[mypath]
	else:
		cacheMiss += 1
		cached_mtime, list, ftype = -1, [], []
	try:
		pathstat = os.stat(mypath)
		if stat.S_ISDIR(pathstat[stat.ST_MODE]):
			mtime = pathstat.st_mtime
		else:
			raise portage.exception.DirectoryNotFound(mypath)
	except EnvironmentError, e:
		if e.errno == portage.exception.PermissionDenied.errno:
			raise portage.exception.PermissionDenied(mypath)
		del e
		if EmptyOnError:
			return [], []
		return None, None
	except portage.exception.PortageException:
		if EmptyOnError:
			return [], []
		return None, None
	# Python retuns mtime in seconds, so if it was changed in the last few seconds, it could be invalid
	if mtime != cached_mtime or time.time() - mtime < 4:
		if mypath in dircache:
			cacheStale += 1
		try:
			list = os.listdir(mypath)
		except EnvironmentError, e:
			if e.errno != errno.EACCES:
				raise
			del e
			raise portage.exception.PermissionDenied(mypath)
		ftype = []
		for x in list:
			try:
				if followSymlinks:
					pathstat = os.stat(mypath+"/"+x)
				else:
					pathstat = os.lstat(mypath+"/"+x)

				if stat.S_ISREG(pathstat[stat.ST_MODE]):
					ftype.append(0)
				elif stat.S_ISDIR(pathstat[stat.ST_MODE]):
					ftype.append(1)
				elif stat.S_ISLNK(pathstat[stat.ST_MODE]):
					ftype.append(2)
				else:
					ftype.append(3)
			except (IOError, OSError):
				ftype.append(3)
		dircache[mypath] = mtime, list, ftype

	ret_list = []
	ret_ftype = []
	for x in range(0, len(list)):
		if(ignorecvs and (len(list[x]) > 2) and (list[x][:2]!=".#")):
			ret_list.append(list[x])
			ret_ftype.append(ftype[x])
		elif (list[x] not in ignorelist):
			ret_list.append(list[x])
			ret_ftype.append(ftype[x])

	writemsg("cacheddirStats: H:%d/M:%d/S:%d\n" % (cacheHit, cacheMiss, cacheStale),10)
	return ret_list, ret_ftype

def listdir(mypath, recursive=False, filesonly=False, ignorecvs=False, ignorelist=[], followSymlinks=True,
	EmptyOnError=False, dirsonly=False):
	"""
	Portage-specific implementation of os.listdir

	@param mypath: Path whose contents you wish to list
	@type mypath: String
	@param recursive: Recursively scan directories contained within mypath
	@type recursive: Boolean
	@param filesonly; Only return files, not more directories
	@type filesonly: Boolean
	@param ignorecvs: Ignore CVS directories ('CVS','.svn','SCCS')
	@type ignorecvs: Boolean
	@param ignorelist: List of filenames/directories to exclude
	@type ignorelist: List
	@param followSymlinks: Follow Symlink'd files and directories
	@type followSymlinks: Boolean
	@param EmptyOnError: Return [] if an error occurs.
	@type EmptyOnError: Boolean
	@param dirsonly: Only return directories.
	@type dirsonly: Boolean
	@rtype: List
	@returns: A list of files and directories (or just files or just directories) or an empty list.
	"""

	list, ftype = cacheddir(mypath, ignorecvs, ignorelist, EmptyOnError, followSymlinks)

	if list is None:
		list=[]
	if ftype is None:
		ftype=[]

	if not (filesonly or dirsonly or recursive):
		return list

	if recursive:
		x=0
		while x<len(ftype):
			if ftype[x]==1 and not (ignorecvs and os.path.basename(list[x]) in ('CVS','.svn','SCCS')):
				l,f = cacheddir(mypath+"/"+list[x], ignorecvs, ignorelist, EmptyOnError,
					followSymlinks)

				l=l[:]
				for y in range(0,len(l)):
					l[y]=list[x]+"/"+l[y]
				list=list+l
				ftype=ftype+f
			x+=1
	if filesonly:
		rlist=[]
		for x in range(0,len(ftype)):
			if ftype[x]==0:
				rlist=rlist+[list[x]]
	elif dirsonly:
		rlist = []
		for x in range(0, len(ftype)):
			if ftype[x] == 1:
				rlist = rlist + [list[x]]	
	else:
		rlist=list

	return rlist

def flatten(mytokens):
	"""this function now turns a [1,[2,3]] list into
	a [1,2,3] list and returns it."""
	newlist=[]
	for x in mytokens:
		if isinstance(x, list):
			newlist.extend(flatten(x))
		else:
			newlist.append(x)
	return newlist

#beautiful directed graph object

class digraph(object):
	def __init__(self):
		"""Create an empty digraph"""
		
		# { node : ( { child : priority } , { parent : priority } ) }
		self.nodes = {}
		self.order = []

	def add(self, node, parent, priority=0):
		"""Adds the specified node with the specified parent.
		
		If the dep is a soft-dep and the node already has a hard
		relationship to the parent, the relationship is left as hard."""
		
		if node not in self.nodes:
			self.nodes[node] = ({}, {})
			self.order.append(node)
		
		if not parent:
			return
		
		if parent not in self.nodes:
			self.nodes[parent] = ({}, {})
			self.order.append(parent)
		
		if parent in self.nodes[node][1]:
			if priority > self.nodes[node][1][parent]:
				self.nodes[node][1][parent] = priority
		else:
			self.nodes[node][1][parent] = priority
		
		if node in self.nodes[parent][0]:
			if priority > self.nodes[parent][0][node]:
				self.nodes[parent][0][node] = priority
		else:
			self.nodes[parent][0][node] = priority

	def remove(self, node):
		"""Removes the specified node from the digraph, also removing
		and ties to other nodes in the digraph. Raises KeyError if the
		node doesn't exist."""
		
		if node not in self.nodes:
			raise KeyError(node)
		
		for parent in self.nodes[node][1]:
			del self.nodes[parent][0][node]
		for child in self.nodes[node][0]:
			del self.nodes[child][1][node]
		
		del self.nodes[node]
		self.order.remove(node)

	def difference_update(self, t):
		"""
		Remove all given nodes from node_set. This is more efficient
		than multiple calls to the remove() method.
		"""
		if isinstance(t, (list, tuple)) or \
			not hasattr(t, "__contains__"):
			t = frozenset(t)
		order = []
		for node in self.order:
			if node not in t:
				order.append(node)
				continue
			for parent in self.nodes[node][1]:
				del self.nodes[parent][0][node]
			for child in self.nodes[node][0]:
				del self.nodes[child][1][node]
			del self.nodes[node]
		self.order = order

	def remove_edge(self, child, parent):
		"""
		Remove edge in the direction from child to parent. Note that it is
		possible for a remaining edge to exist in the opposite direction.
		Any endpoint vertices that become isolated will remain in the graph.
		"""

		# Nothing should be modified when a KeyError is raised.
		for k in parent, child:
			if k not in self.nodes:
				raise KeyError(k)

		# Make sure the edge exists.
		if child not in self.nodes[parent][0]:
			raise KeyError(child)
		if parent not in self.nodes[child][1]:
			raise KeyError(parent)

		# Remove the edge.
		del self.nodes[child][1][parent]
		del self.nodes[parent][0][child]

	def __iter__(self):
		return iter(self.order)

	def contains(self, node):
		"""Checks if the digraph contains mynode"""
		return node in self.nodes

	def get(self, key, default=None):
		return self.nodes.get(key, default)

	def all_nodes(self):
		"""Return a list of all nodes in the graph"""
		return self.order[:]

	def child_nodes(self, node, ignore_priority=None):
		"""Return all children of the specified node"""
		if ignore_priority is None:
			return self.nodes[node][0].keys()
		children = []
		for child, priority in self.nodes[node][0].iteritems():
			if priority > ignore_priority:
				children.append(child)
		return children

	def parent_nodes(self, node):
		"""Return all parents of the specified node"""
		return self.nodes[node][1].keys()

	def leaf_nodes(self, ignore_priority=None):
		"""Return all nodes that have no children
		
		If ignore_soft_deps is True, soft deps are not counted as
		children in calculations."""
		
		leaf_nodes = []
		for node in self.order:
			is_leaf_node = True
			for child in self.nodes[node][0]:
				if self.nodes[node][0][child] > ignore_priority:
					is_leaf_node = False
					break
			if is_leaf_node:
				leaf_nodes.append(node)
		return leaf_nodes

	def root_nodes(self, ignore_priority=None):
		"""Return all nodes that have no parents.
		
		If ignore_soft_deps is True, soft deps are not counted as
		parents in calculations."""
		
		root_nodes = []
		for node in self.order:
			is_root_node = True
			for parent in self.nodes[node][1]:
				if self.nodes[node][1][parent] > ignore_priority:
					is_root_node = False
					break
			if is_root_node:
				root_nodes.append(node)
		return root_nodes

	def is_empty(self):
		"""Checks if the digraph is empty"""
		return len(self.nodes) == 0

	def clone(self):
		clone = digraph()
		clone.nodes = {}
		for k, v in self.nodes.iteritems():
			clone.nodes[k] = (v[0].copy(), v[1].copy())
		clone.order = self.order[:]
		return clone

	# Backward compatibility
	addnode = add
	allnodes = all_nodes
	allzeros = leaf_nodes
	hasnode = contains
	__contains__ = contains
	empty = is_empty
	copy = clone

	def delnode(self, node):
		try:
			self.remove(node)
		except KeyError:
			pass

	def firstzero(self):
		leaf_nodes = self.leaf_nodes()
		if leaf_nodes:
			return leaf_nodes[0]
		return None

	def hasallzeros(self, ignore_priority=None):
		return len(self.leaf_nodes(ignore_priority=ignore_priority)) == \
			len(self.order)

	def debug_print(self):
		for node in self.nodes:
			print node,
			if self.nodes[node][0]:
				print "depends on"
			else:
				print "(no children)"
			for child in self.nodes[node][0]:
				print "  ",child,
				print "(%s)" % self.nodes[node][0][child]

#parse /etc/env.d and generate /etc/profile.env

def env_update(makelinks=1, target_root=None, prev_mtimes=None, contents=None,
	env=None, writemsg_level=portage.util.writemsg_level):
	if target_root is None:
		global settings
		target_root = settings["ROOT"]
	if prev_mtimes is None:
		global mtimedb
		prev_mtimes = mtimedb["ldpath"]
	if env is None:
		env = os.environ
	envd_dir = os.path.join(target_root, "etc", "env.d")
	portage.util.ensure_dirs(envd_dir, mode=0755)
	fns = listdir(envd_dir, EmptyOnError=1)
	fns.sort()
	templist = []
	for x in fns:
		if len(x) < 3:
			continue
		if not x[0].isdigit() or not x[1].isdigit():
			continue
		if x.startswith(".") or x.endswith("~") or x.endswith(".bak"):
			continue
		templist.append(x)
	fns = templist
	del templist

	space_separated = set(["CONFIG_PROTECT", "CONFIG_PROTECT_MASK"])
	colon_separated = set(["ADA_INCLUDE_PATH", "ADA_OBJECTS_PATH",
		"CLASSPATH", "INFODIR", "INFOPATH", "KDEDIRS", "LDPATH", "MANPATH",
		  "PATH", "PKG_CONFIG_PATH", "PRELINK_PATH", "PRELINK_PATH_MASK",
		  "PYTHONPATH", "ROOTPATH"])

	config_list = []

	for x in fns:
		file_path = os.path.join(envd_dir, x)
		try:
			myconfig = getconfig(file_path, expand=False)
		except portage.exception.ParseError, e:
			writemsg("!!! '%s'\n" % str(e), noiselevel=-1)
			del e
			continue
		if myconfig is None:
			# broken symlink or file removed by a concurrent process
			writemsg("!!! File Not Found: '%s'\n" % file_path, noiselevel=-1)
			continue
		config_list.append(myconfig)
		if "SPACE_SEPARATED" in myconfig:
			space_separated.update(myconfig["SPACE_SEPARATED"].split())
			del myconfig["SPACE_SEPARATED"]
		if "COLON_SEPARATED" in myconfig:
			colon_separated.update(myconfig["COLON_SEPARATED"].split())
			del myconfig["COLON_SEPARATED"]

	env = {}
	specials = {}
	for var in space_separated:
		mylist = []
		for myconfig in config_list:
			if var in myconfig:
				for item in myconfig[var].split():
					if item and not item in mylist:
						mylist.append(item)
				del myconfig[var] # prepare for env.update(myconfig)
		if mylist:
			env[var] = " ".join(mylist)
		specials[var] = mylist

	for var in colon_separated:
		mylist = []
		for myconfig in config_list:
			if var in myconfig:
				for item in myconfig[var].split(":"):
					if item and not item in mylist:
						mylist.append(item)
				del myconfig[var] # prepare for env.update(myconfig)
		if mylist:
			env[var] = ":".join(mylist)
		specials[var] = mylist

	for myconfig in config_list:
		"""Cumulative variables have already been deleted from myconfig so that
		they won't be overwritten by this dict.update call."""
		env.update(myconfig)

	ldsoconf_path = os.path.join(target_root, "etc", "ld.so.conf")
	try:
		myld = open(ldsoconf_path)
		myldlines=myld.readlines()
		myld.close()
		oldld=[]
		for x in myldlines:
			#each line has at least one char (a newline)
			if x[0]=="#":
				continue
			oldld.append(x[:-1])
	except (IOError, OSError), e:
		if e.errno != errno.ENOENT:
			raise
		oldld = None

	ld_cache_update=False

	newld = specials["LDPATH"]
	if (oldld!=newld):
		#ld.so.conf needs updating and ldconfig needs to be run
		myfd = atomic_ofstream(ldsoconf_path)
		myfd.write("# ld.so.conf autogenerated by env-update; make all changes to\n")
		myfd.write("# contents of /etc/env.d directory\n")
		for x in specials["LDPATH"]:
			myfd.write(x+"\n")
		myfd.close()
		ld_cache_update=True

	# Update prelink.conf if we are prelink-enabled
	if prelink_capable:
		newprelink = atomic_ofstream(
			os.path.join(target_root, "etc", "prelink.conf"))
		newprelink.write("# prelink.conf autogenerated by env-update; make all changes to\n")
		newprelink.write("# contents of /etc/env.d directory\n")

		for x in ["/bin","/sbin","/usr/bin","/usr/sbin","/lib","/usr/lib"]:
			newprelink.write("-l "+x+"\n");
		for x in specials["LDPATH"]+specials["PATH"]+specials["PRELINK_PATH"]:
			if not x:
				continue
			if x[-1]!='/':
				x=x+"/"
			plmasked=0
			for y in specials["PRELINK_PATH_MASK"]:
				if not y:
					continue
				if y[-1]!='/':
					y=y+"/"
				if y==x[0:len(y)]:
					plmasked=1
					break
			if not plmasked:
				newprelink.write("-h "+x+"\n")
		for x in specials["PRELINK_PATH_MASK"]:
			newprelink.write("-b "+x+"\n")
		newprelink.close()

	# Portage stores mtimes with 1 second granularity but in >=python-2.5 finer
	# granularity is possible.  In order to avoid the potential ambiguity of
	# mtimes that differ by less than 1 second, sleep here if any of the
	# directories have been modified during the current second.
	sleep_for_mtime_granularity = False
	current_time = long(time.time())
	mtime_changed = False
	lib_dirs = set()
	for lib_dir in portage.util.unique_array(specials["LDPATH"]+['usr/lib','usr/lib64','usr/lib32','lib','lib64','lib32']):
		x = os.path.join(target_root, lib_dir.lstrip(os.sep))
		try:
			newldpathtime = long(os.stat(x).st_mtime)
			lib_dirs.add(normalize_path(x))
		except OSError, oe:
			if oe.errno == errno.ENOENT:
				try:
					del prev_mtimes[x]
				except KeyError:
					pass
				# ignore this path because it doesn't exist
				continue
			raise
		if newldpathtime == current_time:
			sleep_for_mtime_granularity = True
		if x in prev_mtimes:
			if prev_mtimes[x] == newldpathtime:
				pass
			else:
				prev_mtimes[x] = newldpathtime
				mtime_changed = True
		else:
			prev_mtimes[x] = newldpathtime
			mtime_changed = True

	if mtime_changed:
		ld_cache_update = True

	if makelinks and \
		not ld_cache_update and \
		contents is not None:
		libdir_contents_changed = False
		for mypath, mydata in contents.iteritems():
			if mydata[0] not in ("obj","sym"):
				continue
			head, tail = os.path.split(mypath)
			if head in lib_dirs:
				libdir_contents_changed = True
				break
		if not libdir_contents_changed:
			makelinks = False

	ldconfig = "/sbin/ldconfig"
	if "CHOST" in env and "CBUILD" in env and \
		env["CHOST"] != env["CBUILD"]:
		from portage.process import find_binary
		ldconfig = find_binary("%s-ldconfig" % env["CHOST"])

	# Only run ldconfig as needed
	if (ld_cache_update or makelinks) and ldconfig:
		# ldconfig has very different behaviour between FreeBSD and Linux
		if ostype=="Linux" or ostype.lower().endswith("gnu"):
			# We can't update links if we haven't cleaned other versions first, as
			# an older package installed ON TOP of a newer version will cause ldconfig
			# to overwrite the symlinks we just made. -X means no links. After 'clean'
			# we can safely create links.
			writemsg_level(">>> Regenerating %setc/ld.so.cache...\n" % \
				(target_root,))
			if makelinks:
				os.system("cd / ; %s -r '%s'" % (ldconfig, target_root))
			else:
				os.system("cd / ; %s -X -r '%s'" % (ldconfig, target_root))
		elif ostype in ("FreeBSD","DragonFly"):
			writemsg_level(">>> Regenerating %svar/run/ld-elf.so.hints...\n" % \
				target_root)
			os.system(("cd / ; %s -elf -i " + \
				"-f '%svar/run/ld-elf.so.hints' '%setc/ld.so.conf'") % \
				(ldconfig, target_root, target_root))

	del specials["LDPATH"]

	penvnotice  = "# THIS FILE IS AUTOMATICALLY GENERATED BY env-update.\n"
	penvnotice += "# DO NOT EDIT THIS FILE. CHANGES TO STARTUP PROFILES\n"
	cenvnotice  = penvnotice[:]
	penvnotice += "# GO INTO /etc/profile NOT /etc/profile.env\n\n"
	cenvnotice += "# GO INTO /etc/csh.cshrc NOT /etc/csh.env\n\n"

	#create /etc/profile.env for bash support
	outfile = atomic_ofstream(os.path.join(target_root, "etc", "profile.env"))
	outfile.write(penvnotice)

	env_keys = [ x for x in env if x != "LDPATH" ]
	env_keys.sort()
	for k in env_keys:
		v = env[k]
		if v.startswith('$') and not v.startswith('${'):
			outfile.write("export %s=$'%s'\n" % (k, v[1:]))
		else:
			outfile.write("export %s='%s'\n" % (k, v))
	outfile.close()

	#create /etc/csh.env for (t)csh support
	outfile = atomic_ofstream(os.path.join(target_root, "etc", "csh.env"))
	outfile.write(cenvnotice)
	for x in env_keys:
		outfile.write("setenv %s '%s'\n" % (x, env[x]))
	outfile.close()

	if sleep_for_mtime_granularity:
		while current_time == long(time.time()):
			sleep(1)

def ExtractKernelVersion(base_dir):
	"""
	Try to figure out what kernel version we are running
	@param base_dir: Path to sources (usually /usr/src/linux)
	@type base_dir: string
	@rtype: tuple( version[string], error[string])
	@returns:
	1. tuple( version[string], error[string])
	Either version or error is populated (but never both)

	"""
	lines = []
	pathname = os.path.join(base_dir, 'Makefile')
	try:
		f = open(pathname, 'r')
	except OSError, details:
		return (None, str(details))
	except IOError, details:
		return (None, str(details))

	try:
		for i in range(4):
			lines.append(f.readline())
	except OSError, details:
		return (None, str(details))
	except IOError, details:
		return (None, str(details))

	lines = [l.strip() for l in lines]

	version = ''

	#XXX: The following code relies on the ordering of vars within the Makefile
	for line in lines:
		# split on the '=' then remove annoying whitespace
		items = line.split("=")
		items = [i.strip() for i in items]
		if items[0] == 'VERSION' or \
			items[0] == 'PATCHLEVEL':
			version += items[1]
			version += "."
		elif items[0] == 'SUBLEVEL':
			version += items[1]
		elif items[0] == 'EXTRAVERSION' and \
			items[-1] != items[0]:
			version += items[1]

	# Grab a list of files named localversion* and sort them
	localversions = os.listdir(base_dir)
	for x in range(len(localversions)-1,-1,-1):
		if localversions[x][:12] != "localversion":
			del localversions[x]
	localversions.sort()

	# Append the contents of each to the version string, stripping ALL whitespace
	for lv in localversions:
		version += "".join( " ".join( grabfile( base_dir+ "/" + lv ) ).split() )

	# Check the .config for a CONFIG_LOCALVERSION and append that too, also stripping whitespace
	kernelconfig = getconfig(base_dir+"/.config")
	if kernelconfig and "CONFIG_LOCALVERSION" in kernelconfig:
		version += "".join(kernelconfig["CONFIG_LOCALVERSION"].split())

	return (version,None)

def autouse(myvartree, use_cache=1, mysettings=None):
	"""
	autuse returns a list of USE variables auto-enabled to packages being installed

	@param myvartree: Instance of the vartree class (from /var/db/pkg...)
	@type myvartree: vartree
	@param use_cache: read values from cache
	@type use_cache: Boolean
	@param mysettings: Instance of config
	@type mysettings: config
	@rtype: string
	@returns: A string containing a list of USE variables that are enabled via use.defaults
	"""
	if mysettings is None:
		global settings
		mysettings = settings
	if mysettings.profile_path is None:
		return ""
	myusevars=""
	usedefaults = mysettings.use_defs
	for myuse in usedefaults:
		dep_met = True
		for mydep in usedefaults[myuse]:
			if not myvartree.dep_match(mydep,use_cache=True):
				dep_met = False
				break
		if dep_met:
			myusevars += " "+myuse
	return myusevars

def check_config_instance(test):
	if not isinstance(test, config):
		raise TypeError("Invalid type for config object: %s (should be %s)" % (test.__class__, config))

class config(object):
	"""
	This class encompasses the main portage configuration.  Data is pulled from
	ROOT/PORTDIR/profiles/, from ROOT/etc/make.profile incrementally through all 
	parent profiles as well as from ROOT/PORTAGE_CONFIGROOT/* for user specified
	overrides.
	
	Generally if you need data like USE flags, FEATURES, environment variables,
	virtuals ...etc you look in here.
	"""

	_environ_whitelist = []

	# Whitelisted variables are always allowed to enter the ebuild
	# environment. Generally, this only includes special portage
	# variables. Ebuilds can unset variables that are not whitelisted
	# and rely on them remaining unset for future phases, without them
	# leaking back in from various locations (bug #189417). It's very
	# important to set our special BASH_ENV variable in the ebuild
	# environment in order to prevent sandbox from sourcing /etc/profile
	# in it's bashrc (causing major leakage).
	_environ_whitelist += [
		"BASH_ENV", "BUILD_PREFIX", "D",
		"DISTDIR", "DOC_SYMLINKS_DIR", "EBUILD",
		"EBUILD_EXIT_STATUS_FILE", "EBUILD_FORCE_TEST",
		"EBUILD_PHASE", "ECLASSDIR", "ECLASS_DEPTH", "EMERGE_FROM",
		"FEATURES", "FILESDIR", "HOME", "PATH",
		"PKGDIR",
		"PKGUSE", "PKG_LOGDIR", "PKG_TMPDIR",
		"PORTAGE_ACTUAL_DISTDIR", "PORTAGE_ARCHLIST",
		"PORTAGE_BASHRC",
		"PORTAGE_BINPKG_FILE", "PORTAGE_BINPKG_TAR_OPTS",
		"PORTAGE_BINPKG_TMPFILE",
		"PORTAGE_BIN_PATH",
		"PORTAGE_BUILDDIR", "PORTAGE_COLORMAP",
		"PORTAGE_CONFIGROOT", "PORTAGE_DEBUG", "PORTAGE_DEPCACHEDIR",
		"PORTAGE_GID", "PORTAGE_INST_GID", "PORTAGE_INST_UID",
		"PORTAGE_IUSE",
		"PORTAGE_LOG_FILE", "PORTAGE_MASTER_PID",
		"PORTAGE_PYM_PATH", "PORTAGE_REPO_NAME", "PORTAGE_RESTRICT",
		"PORTAGE_TMPDIR", "PORTAGE_UPDATE_ENV", "PORTAGE_WORKDIR_MODE",
		"PORTDIR", "PORTDIR_OVERLAY", "PREROOTPATH", "PROFILE_PATHS",
		"ROOT", "ROOTPATH", "STARTDIR", "T", "TMP", "TMPDIR",
		"USE_EXPAND", "USE_ORDER", "WORKDIR",
		"XARGS",
	]

	# user config variables
	_environ_whitelist += [
		"DOC_SYMLINKS_DIR", "INSTALL_MASK", "PKG_INSTALL_MASK"
	]

	_environ_whitelist += [
		"A", "AA", "CATEGORY", "P", "PF", "PN", "PR", "PV", "PVR"
	]

	# misc variables inherited from the calling environment
	_environ_whitelist += [
		"COLORTERM", "DISPLAY", "EDITOR", "LESS",
		"LESSOPEN", "LOGNAME", "LS_COLORS", "PAGER",
		"TERM", "TERMCAP", "USER",
	]

	# other variables inherited from the calling environment
	_environ_whitelist += [
		"CVS_RSH", "ECHANGELOG_USER",
		"GPG_AGENT_INFO",
		"SSH_AGENT_PID", "SSH_AUTH_SOCK",
		"STY", "WINDOW", "XAUTHORITY",
	]

	_environ_whitelist = frozenset(_environ_whitelist)

	_environ_whitelist_re = re.compile(r'^(CCACHE_|DISTCC_).*')

	# Filter selected variables in the config.environ() method so that
	# they don't needlessly propagate down into the ebuild environment.
	_environ_filter = []

	# misc variables inherited from the calling environment
	_environ_filter += [
		"INFOPATH", "MANPATH",
	]

	# portage config variables and variables set directly by portage
	_environ_filter += [
		"ACCEPT_KEYWORDS", "AUTOCLEAN",
		"CLEAN_DELAY", "COLLISION_IGNORE", "CONFIG_PROTECT",
		"CONFIG_PROTECT_MASK", "EMERGE_DEFAULT_OPTS",
		"EMERGE_WARNING_DELAY", "FETCHCOMMAND", "FETCHCOMMAND_FTP",
		"FETCHCOMMAND_HTTP", "FETCHCOMMAND_SFTP",
		"GENTOO_MIRRORS", "NOCONFMEM", "O",
		"PORTAGE_BINHOST_CHUNKSIZE", "PORTAGE_CALLER",
		"PORTAGE_ECLASS_WARNING_ENABLE", "PORTAGE_ELOG_CLASSES",
		"PORTAGE_ELOG_MAILFROM", "PORTAGE_ELOG_MAILSUBJECT",
		"PORTAGE_ELOG_MAILURI", "PORTAGE_ELOG_SYSTEM",
		"PORTAGE_FETCH_CHECKSUM_TRY_MIRRORS", "PORTAGE_FETCH_RESUME_MIN_SIZE",
		"PORTAGE_GPG_DIR",
		"PORTAGE_GPG_KEY", "PORTAGE_IONICE_COMMAND",
		"PORTAGE_PACKAGE_EMPTY_ABORT",
		"PORTAGE_RO_DISTDIRS",
		"PORTAGE_RSYNC_EXTRA_OPTS", "PORTAGE_RSYNC_OPTS",
		"PORTAGE_RSYNC_RETRIES", "PORTAGE_USE", "PORT_LOGDIR",
		"QUICKPKG_DEFAULT_OPTS",
		"RESUMECOMMAND", "RESUMECOMMAND_HTTP", "RESUMECOMMAND_HTTP",
		"RESUMECOMMAND_SFTP", "SYNC", "USE_EXPAND_HIDDEN", "USE_ORDER",
	]

	_environ_filter = frozenset(_environ_filter)

	def __init__(self, clone=None, mycpv=None, config_profile_path=None,
		config_incrementals=None, config_root=None, target_root=None,
		local_config=True):
		"""
		@param clone: If provided, init will use deepcopy to copy by value the instance.
		@type clone: Instance of config class.
		@param mycpv: CPV to load up (see setcpv), this is the same as calling init with mycpv=None
		and then calling instance.setcpv(mycpv).
		@type mycpv: String
		@param config_profile_path: Configurable path to the profile (usually PROFILE_PATH from portage.const)
		@type config_profile_path: String
		@param config_incrementals: List of incremental variables (usually portage.const.INCREMENTALS)
		@type config_incrementals: List
		@param config_root: path to read local config from (defaults to "/", see PORTAGE_CONFIGROOT)
		@type config_root: String
		@param target_root: __init__ override of $ROOT env variable.
		@type target_root: String
		@param local_config: Enables loading of local config (/etc/portage); used most by repoman to
		ignore local config (keywording and unmasking)
		@type local_config: Boolean
		"""

		# When initializing the global portage.settings instance, avoid
		# raising exceptions whenever possible since exceptions thrown
		# from 'import portage' or 'import portage.exceptions' statements
		# can practically render the api unusable for api consumers.
		tolerant = "_initializing_globals" in globals()

		self.already_in_regenerate = 0

		self.locked   = 0
		self.mycpv    = None
		self.puse     = []
		self.modifiedkeys = []
		self.uvlist = []
		self._accept_chost_re = None

		self.virtuals = {}
		self.virts_p = {}
		self.dirVirtuals = None
		self.v_count  = 0

		# Virtuals obtained from the vartree
		self.treeVirtuals = {}
		# Virtuals by user specification. Includes negatives.
		self.userVirtuals = {}
		# Virtual negatives from user specifications.
		self.negVirtuals  = {}
		# Virtuals added by the depgraph via self.setinst().
		self._depgraphVirtuals = {}

		self.user_profile_dir = None
		self.local_config = local_config

		if clone:
			self.incrementals = copy.deepcopy(clone.incrementals)
			self.profile_path = copy.deepcopy(clone.profile_path)
			self.user_profile_dir = copy.deepcopy(clone.user_profile_dir)
			self.local_config = copy.deepcopy(clone.local_config)

			self.module_priority = copy.deepcopy(clone.module_priority)
			self.modules         = copy.deepcopy(clone.modules)

			self.depcachedir = copy.deepcopy(clone.depcachedir)

			self.packages = copy.deepcopy(clone.packages)
			self.virtuals = copy.deepcopy(clone.virtuals)

			self.dirVirtuals = copy.deepcopy(clone.dirVirtuals)
			self.treeVirtuals = copy.deepcopy(clone.treeVirtuals)
			self.userVirtuals = copy.deepcopy(clone.userVirtuals)
			self.negVirtuals  = copy.deepcopy(clone.negVirtuals)
			self._depgraphVirtuals = copy.deepcopy(clone._depgraphVirtuals)

			self.use_defs = copy.deepcopy(clone.use_defs)
			self.usemask  = copy.deepcopy(clone.usemask)
			self.usemask_list = copy.deepcopy(clone.usemask_list)
			self.pusemask_list = copy.deepcopy(clone.pusemask_list)
			self.useforce      = copy.deepcopy(clone.useforce)
			self.useforce_list = copy.deepcopy(clone.useforce_list)
			self.puseforce_list = copy.deepcopy(clone.puseforce_list)
			self.puse     = copy.deepcopy(clone.puse)
			self.make_defaults_use = copy.deepcopy(clone.make_defaults_use)
			self.pkgprofileuse = copy.deepcopy(clone.pkgprofileuse)
			self.mycpv    = copy.deepcopy(clone.mycpv)

			self.configlist = copy.deepcopy(clone.configlist)
			self.lookuplist = self.configlist[:]
			self.lookuplist.reverse()
			self.configdict = {
				"env.d":     self.configlist[0],
				"pkginternal": self.configlist[1],
				"globals":     self.configlist[2],
				"defaults":    self.configlist[3],
				"conf":        self.configlist[4],
				"pkg":         self.configlist[5],
				"auto":        self.configlist[6],
				"backupenv":   self.configlist[7],
				"env":         self.configlist[8] }
			self.profiles = copy.deepcopy(clone.profiles)
			self.backupenv  = self.configdict["backupenv"]
			self.pusedict   = copy.deepcopy(clone.pusedict)
			self.categories = copy.deepcopy(clone.categories)
			self.pkeywordsdict = copy.deepcopy(clone.pkeywordsdict)
			self.pmaskdict = copy.deepcopy(clone.pmaskdict)
			self.punmaskdict = copy.deepcopy(clone.punmaskdict)
			self.prevmaskdict = copy.deepcopy(clone.prevmaskdict)
			self.pprovideddict = copy.deepcopy(clone.pprovideddict)
			self.features = copy.deepcopy(clone.features)

			self._accept_license = copy.deepcopy(clone._accept_license)
			self._plicensedict = copy.deepcopy(clone._plicensedict)
		else:

			def check_var_directory(varname, var):
				if not os.path.isdir(var):
					writemsg(("!!! Error: %s='%s' is not a directory. " + \
						"Please correct this.\n") % (varname, var),
						noiselevel=-1)
					raise portage.exception.DirectoryNotFound(var)

			if config_root is None:
				config_root = "/"

			config_root = normalize_path(os.path.abspath(
				config_root)).rstrip(os.path.sep) + os.path.sep

			check_var_directory("PORTAGE_CONFIGROOT", config_root)

			self.depcachedir = DEPCACHE_PATH

			if not config_profile_path:
				config_profile_path = \
					os.path.join(config_root, PROFILE_PATH.lstrip(os.path.sep))
				if os.path.isdir(config_profile_path):
					self.profile_path = config_profile_path
				else:
					self.profile_path = None
			else:
				self.profile_path = config_profile_path[:]

			if not config_incrementals:
				writemsg("incrementals not specified to class config\n")
				self.incrementals = copy.deepcopy(portage.const.INCREMENTALS)
			else:
				self.incrementals = copy.deepcopy(config_incrementals)

			self.module_priority    = ["user","default"]
			self.modules            = {}
			self.modules["user"] = getconfig(
				os.path.join(config_root, MODULES_FILE_PATH.lstrip(os.path.sep)))
			if self.modules["user"] is None:
				self.modules["user"] = {}
			self.modules["default"] = {
				"portdbapi.metadbmodule": "portage.cache.metadata.database",
				"portdbapi.auxdbmodule":  "portage.cache.flat_hash.database",
			}

			self.usemask=[]
			self.configlist=[]

			# back up our incremental variables:
			self.configdict={}
			# configlist will contain: [ env.d, globals, defaults, conf, pkg, auto, backupenv, env ]
			self.configlist.append({})
			self.configdict["env.d"] = self.configlist[-1]

			self.configlist.append({})
			self.configdict["pkginternal"] = self.configlist[-1]

			# The symlink might not exist or might not be a symlink.
			if self.profile_path is None:
				self.profiles = []
			else:
				self.profiles = []
				def addProfile(currentPath):
					parentsFile = os.path.join(currentPath, "parent")
					if os.path.exists(parentsFile):
						parents = grabfile(parentsFile)
						if not parents:
							raise portage.exception.ParseError(
								"Empty parent file: '%s'" % parentsFile)
						for parentPath in parents:
							parentPath = normalize_path(os.path.join(
								currentPath, parentPath))
							if os.path.exists(parentPath):
								addProfile(parentPath)
							else:
								raise portage.exception.ParseError(
									"Parent '%s' not found: '%s'" %  \
									(parentPath, parentsFile))
					self.profiles.append(currentPath)
				try:
					addProfile(os.path.realpath(self.profile_path))
				except portage.exception.ParseError, e:
					writemsg("!!! Unable to parse profile: '%s'\n" % \
						self.profile_path, noiselevel=-1)
					writemsg("!!! ParseError: %s\n" % str(e), noiselevel=-1)
					del e
					self.profiles = []
			if local_config:
				custom_prof = os.path.join(
					config_root, CUSTOM_PROFILE_PATH.lstrip(os.path.sep))
				if os.path.exists(custom_prof):
					self.user_profile_dir = custom_prof
					self.profiles.append(custom_prof)
				del custom_prof

			self.packages_list = [grabfile_package(os.path.join(x, "packages")) for x in self.profiles]
			self.packages      = stack_lists(self.packages_list, incremental=1)
			del self.packages_list
			#self.packages = grab_stacked("packages", self.profiles, grabfile, incremental_lines=1)

			# revmaskdict
			self.prevmaskdict={}
			for x in self.packages:
				mycatpkg=dep_getkey(x)
				if mycatpkg not in self.prevmaskdict:
					self.prevmaskdict[mycatpkg]=[x]
				else:
					self.prevmaskdict[mycatpkg].append(x)

			# get profile-masked use flags -- INCREMENTAL Child over parent
			self.usemask_list = [grabfile(os.path.join(x, "use.mask")) \
				for x in self.profiles]
			self.usemask  = set(stack_lists(
				self.usemask_list, incremental=True))
			use_defs_lists = [grabdict(os.path.join(x, "use.defaults")) for x in self.profiles]
			self.use_defs  = stack_dictlist(use_defs_lists, incremental=True)
			del use_defs_lists

			self.pusemask_list = []
			rawpusemask = [grabdict_package(
				os.path.join(x, "package.use.mask")) \
				for x in self.profiles]
			for i in xrange(len(self.profiles)):
				cpdict = {}
				for k, v in rawpusemask[i].iteritems():
					cpdict.setdefault(dep_getkey(k), {})[k] = v
				self.pusemask_list.append(cpdict)
			del rawpusemask

			self.pkgprofileuse = []
			rawprofileuse = [grabdict_package(
				os.path.join(x, "package.use"), juststrings=True) \
				for x in self.profiles]
			for i in xrange(len(self.profiles)):
				cpdict = {}
				for k, v in rawprofileuse[i].iteritems():
					cpdict.setdefault(dep_getkey(k), {})[k] = v
				self.pkgprofileuse.append(cpdict)
			del rawprofileuse

			self.useforce_list = [grabfile(os.path.join(x, "use.force")) \
				for x in self.profiles]
			self.useforce  = set(stack_lists(
				self.useforce_list, incremental=True))

			self.puseforce_list = []
			rawpuseforce = [grabdict_package(
				os.path.join(x, "package.use.force")) \
				for x in self.profiles]
			for i in xrange(len(self.profiles)):
				cpdict = {}
				for k, v in rawpuseforce[i].iteritems():
					cpdict.setdefault(dep_getkey(k), {})[k] = v
				self.puseforce_list.append(cpdict)
			del rawpuseforce

			make_conf = getconfig(
				os.path.join(config_root, MAKE_CONF_FILE.lstrip(os.path.sep)),
				tolerant=tolerant, allow_sourcing=True)
			if make_conf is None:
				make_conf = {}

			# Allow ROOT setting to come from make.conf if it's not overridden
			# by the constructor argument (from the calling environment).
			if target_root is None and "ROOT" in make_conf:
				target_root = make_conf["ROOT"]
				if not target_root.strip():
					target_root = None
			if target_root is None:
				target_root = "/"

			target_root = normalize_path(os.path.abspath(
				target_root)).rstrip(os.path.sep) + os.path.sep

			portage.util.ensure_dirs(target_root)
			check_var_directory("ROOT", target_root)

			# The expand_map is used for variable substitution
			# in getconfig() calls, and the getconfig() calls
			# update expand_map with the value of each variable
			# assignment that occurs. Variable substitution occurs
			# in the following order, which corresponds to the
			# order of appearance in self.lookuplist:
			#
			#   * env.d
			#   * make.globals
			#   * make.defaults
			#   * make.conf
			#
			# Notably absent is "env", since we want to avoid any
			# interaction with the calling environment that might
			# lead to unexpected results.
			expand_map = {}

			env_d = getconfig(os.path.join(target_root, "etc", "profile.env"),
				expand=expand_map)
			# env_d will be None if profile.env doesn't exist.
			if env_d:
				self.configdict["env.d"].update(env_d)
				expand_map.update(env_d)

			# backupenv is used for calculating incremental variables.
			self.backupenv = os.environ.copy()

			if env_d:
				# Remove duplicate values so they don't override updated
				# profile.env values later (profile.env is reloaded in each
				# call to self.regenerate).
				for k, v in env_d.iteritems():
					try:
						if self.backupenv[k] == v:
							del self.backupenv[k]
					except KeyError:
						pass
				del k, v

			self.configdict["env"] = self.backupenv.copy()

			# make.globals should not be relative to config_root
			# because it only contains constants.
			self.mygcfg = getconfig(os.path.join("/etc", "make.globals"),
				expand=expand_map)

			if self.mygcfg is None:
				self.mygcfg = {}

			self.configlist.append(self.mygcfg)
			self.configdict["globals"]=self.configlist[-1]

			self.make_defaults_use = []
			self.mygcfg = {}
			if self.profiles:
				mygcfg_dlists = [getconfig(os.path.join(x, "make.defaults"),
					expand=expand_map) for x in self.profiles]

				for cfg in mygcfg_dlists:
					if cfg:
						self.make_defaults_use.append(cfg.get("USE", ""))
					else:
						self.make_defaults_use.append("")
				self.mygcfg = stack_dicts(mygcfg_dlists,
					incrementals=portage.const.INCREMENTALS, ignore_none=1)
				if self.mygcfg is None:
					self.mygcfg = {}
			self.configlist.append(self.mygcfg)
			self.configdict["defaults"]=self.configlist[-1]

			self.mygcfg = getconfig(
				os.path.join(config_root, MAKE_CONF_FILE.lstrip(os.path.sep)),
				tolerant=tolerant, allow_sourcing=True, expand=expand_map)
			if self.mygcfg is None:
				self.mygcfg = {}

			# Don't allow the user to override certain variables in make.conf
			profile_only_variables = self.configdict["defaults"].get(
				"PROFILE_ONLY_VARIABLES", "").split()
			for k in profile_only_variables:
				self.mygcfg.pop(k, None)

			self.configlist.append(self.mygcfg)
			self.configdict["conf"]=self.configlist[-1]

			self.configlist.append({})
			self.configdict["pkg"]=self.configlist[-1]

			#auto-use:
			self.configlist.append({})
			self.configdict["auto"]=self.configlist[-1]

			self.configlist.append(self.backupenv) # XXX Why though?
			self.configdict["backupenv"]=self.configlist[-1]

			# Don't allow the user to override certain variables in the env
			for k in profile_only_variables:
				self.backupenv.pop(k, None)

			self.configlist.append(self.configdict["env"])

			# make lookuplist for loading package.*
			self.lookuplist=self.configlist[:]
			self.lookuplist.reverse()

			# Blacklist vars that could interfere with portage internals.
			for blacklisted in "CATEGORY", "EBUILD_PHASE", \
				"EMERGE_FROM", "PKGUSE", "PORTAGE_CONFIGROOT", \
				"PORTAGE_IUSE", "PORTAGE_USE", "ROOT":
				for cfg in self.lookuplist:
					cfg.pop(blacklisted, None)
			del blacklisted, cfg

			self["PORTAGE_CONFIGROOT"] = config_root
			self.backup_changes("PORTAGE_CONFIGROOT")
			self["ROOT"] = target_root
			self.backup_changes("ROOT")

			self.pusedict = {}
			self.pkeywordsdict = {}
			self._plicensedict = {}
			self.punmaskdict = {}
			abs_user_config = os.path.join(config_root,
				USER_CONFIG_PATH.lstrip(os.path.sep))

			# locations for "categories" and "arch.list" files
			locations = [os.path.join(self["PORTDIR"], "profiles")]
			pmask_locations = [os.path.join(self["PORTDIR"], "profiles")]
			pmask_locations.extend(self.profiles)

			""" repoman controls PORTDIR_OVERLAY via the environment, so no
			special cases are needed here."""
			overlay_profiles = []
			for ov in self["PORTDIR_OVERLAY"].split():
				ov = normalize_path(ov)
				profiles_dir = os.path.join(ov, "profiles")
				if os.path.isdir(profiles_dir):
					overlay_profiles.append(profiles_dir)
			locations += overlay_profiles
			
			pmask_locations.extend(overlay_profiles)

			if local_config:
				locations.append(abs_user_config)
				pmask_locations.append(abs_user_config)
				pusedict = grabdict_package(
					os.path.join(abs_user_config, "package.use"), recursive=1)
				for key in pusedict.keys():
					cp = dep_getkey(key)
					if cp not in self.pusedict:
						self.pusedict[cp] = {}
					self.pusedict[cp][key] = pusedict[key]

				#package.keywords
				pkgdict = grabdict_package(
					os.path.join(abs_user_config, "package.keywords"),
					recursive=1)
				for key in pkgdict.keys():
					# default to ~arch if no specific keyword is given
					if not pkgdict[key]:
						mykeywordlist = []
						if self.configdict["defaults"] and \
							"ACCEPT_KEYWORDS" in self.configdict["defaults"]:
							groups = self.configdict["defaults"]["ACCEPT_KEYWORDS"].split()
						else:
							groups = []
						for keyword in groups:
							if not keyword[0] in "~-":
								mykeywordlist.append("~"+keyword)
						pkgdict[key] = mykeywordlist
					cp = dep_getkey(key)
					if cp not in self.pkeywordsdict:
						self.pkeywordsdict[cp] = {}
					self.pkeywordsdict[cp][key] = pkgdict[key]
				
				#package.license
				licdict = grabdict_package(os.path.join(
					abs_user_config, "package.license"), recursive=1)
				for k, v in licdict.iteritems():
					cp = dep_getkey(k)
					cp_dict = self._plicensedict.get(cp)
					if not cp_dict:
						cp_dict = {}
						self._plicensedict[cp] = cp_dict
					cp_dict[k] = self.expandLicenseTokens(v)

				#package.unmask
				pkgunmasklines = grabfile_package(
					os.path.join(abs_user_config, "package.unmask"),
					recursive=1)
				for x in pkgunmasklines:
					mycatpkg=dep_getkey(x)
					if mycatpkg in self.punmaskdict:
						self.punmaskdict[mycatpkg].append(x)
					else:
						self.punmaskdict[mycatpkg]=[x]

			#getting categories from an external file now
			categories = [grabfile(os.path.join(x, "categories")) for x in locations]
			self.categories = stack_lists(categories, incremental=1)
			del categories

			archlist = [grabfile(os.path.join(x, "arch.list")) for x in locations]
			archlist = stack_lists(archlist, incremental=1)
			self.configdict["conf"]["PORTAGE_ARCHLIST"] = " ".join(archlist)

			#package.mask
			pkgmasklines = []
			for x in pmask_locations:
				pkgmasklines.append(grabfile_package(
					os.path.join(x, "package.mask"), recursive=1))
			pkgmasklines = stack_lists(pkgmasklines, incremental=1)

			self.pmaskdict = {}
			for x in pkgmasklines:
				mycatpkg=dep_getkey(x)
				if mycatpkg in self.pmaskdict:
					self.pmaskdict[mycatpkg].append(x)
				else:
					self.pmaskdict[mycatpkg]=[x]

			pkgprovidedlines = [grabfile(os.path.join(x, "package.provided")) for x in self.profiles]
			pkgprovidedlines = stack_lists(pkgprovidedlines, incremental=1)
			has_invalid_data = False
			for x in range(len(pkgprovidedlines)-1, -1, -1):
				myline = pkgprovidedlines[x]
				if not isvalidatom("=" + myline):
					writemsg("Invalid package name in package.provided:" + \
						" %s\n" % myline, noiselevel=-1)
					has_invalid_data = True
					del pkgprovidedlines[x]
					continue
				cpvr = catpkgsplit(pkgprovidedlines[x])
				if not cpvr or cpvr[0] == "null":
					writemsg("Invalid package name in package.provided: "+pkgprovidedlines[x]+"\n",
						noiselevel=-1)
					has_invalid_data = True
					del pkgprovidedlines[x]
					continue
				if cpvr[0] == "virtual":
					writemsg("Virtual package in package.provided: %s\n" % \
						myline, noiselevel=-1)
					has_invalid_data = True
					del pkgprovidedlines[x]
					continue
			if has_invalid_data:
				writemsg("See portage(5) for correct package.provided usage.\n",
					noiselevel=-1)
			self.pprovideddict = {}
			for x in pkgprovidedlines:
				cpv=catpkgsplit(x)
				if not x:
					continue
				mycatpkg=dep_getkey(x)
				if mycatpkg in self.pprovideddict:
					self.pprovideddict[mycatpkg].append(x)
				else:
					self.pprovideddict[mycatpkg]=[x]

			# parse licensegroups
			self._license_groups = {}
			for x in locations:
				self._license_groups.update(
					grabdict(os.path.join(x, "license_groups")))

			# reasonable defaults; this is important as without USE_ORDER,
			# USE will always be "" (nothing set)!
			if "USE_ORDER" not in self:
				self.backupenv["USE_ORDER"] = "env:pkg:conf:defaults:pkginternal:env.d"

			self["PORTAGE_GID"] = str(portage_gid)
			self.backup_changes("PORTAGE_GID")

			if self.get("PORTAGE_DEPCACHEDIR", None):
				self.depcachedir = self["PORTAGE_DEPCACHEDIR"]
			self["PORTAGE_DEPCACHEDIR"] = self.depcachedir
			self.backup_changes("PORTAGE_DEPCACHEDIR")

			overlays = self.get("PORTDIR_OVERLAY","").split()
			if overlays:
				new_ov = []
				for ov in overlays:
					ov = normalize_path(ov)
					if os.path.isdir(ov):
						new_ov.append(ov)
					else:
						writemsg("!!! Invalid PORTDIR_OVERLAY" + \
							" (not a dir): '%s'\n" % ov, noiselevel=-1)
				self["PORTDIR_OVERLAY"] = " ".join(new_ov)
				self.backup_changes("PORTDIR_OVERLAY")

			if "CBUILD" not in self and "CHOST" in self:
				self["CBUILD"] = self["CHOST"]
				self.backup_changes("CBUILD")

			self["PORTAGE_BIN_PATH"] = PORTAGE_BIN_PATH
			self.backup_changes("PORTAGE_BIN_PATH")
			self["PORTAGE_PYM_PATH"] = PORTAGE_PYM_PATH
			self.backup_changes("PORTAGE_PYM_PATH")

			# Expand license groups
			# This has to do be done for each config layer before regenerate()
			# in order for incremental negation to work properly.
			if local_config:
				for c in self.configdict.itervalues():
					v = c.get("ACCEPT_LICENSE")
					if not v:
						continue
					v = " ".join(self.expandLicenseTokens(v.split()))
					c["ACCEPT_LICENSE"] = v
					del c, v

			for var in ("PORTAGE_INST_UID", "PORTAGE_INST_GID"):
				try:
					self[var] = str(int(self.get(var, "0")))
				except ValueError:
					writemsg(("!!! %s='%s' is not a valid integer.  " + \
						"Falling back to '0'.\n") % (var, self[var]),
						noiselevel=-1)
					self[var] = "0"
				self.backup_changes(var)

			# initialize self.features
			self.regenerate()

			if local_config:
				self._accept_license = \
					set(self.get("ACCEPT_LICENSE", "").split())
				# In order to enforce explicit acceptance for restrictive
				# licenses that require it, "*" will not be allowed in the
				# user config.  Don't enforce this until license groups are
				# fully implemented in the tree.
				#self._accept_license.discard("*")
				if not self._accept_license:
					self._accept_license = set(["*"])
			else:
				# repoman will accept any license
				self._accept_license = set(["*"])

			if "gpg" in self.features:
				if not os.path.exists(self["PORTAGE_GPG_DIR"]) or \
					not os.path.isdir(self["PORTAGE_GPG_DIR"]):
					writemsg(colorize("BAD", "PORTAGE_GPG_DIR is invalid." + \
						" Removing gpg from FEATURES.\n"), noiselevel=-1)
					self.features.remove("gpg")

			if not portage.process.sandbox_capable and \
				("sandbox" in self.features or "usersandbox" in self.features):
				if self.profile_path is not None and \
					os.path.realpath(self.profile_path) == \
					os.path.realpath(PROFILE_PATH):
					""" Don't show this warning when running repoman and the
					sandbox feature came from a profile that doesn't belong to
					the user."""
					writemsg(colorize("BAD", "!!! Problem with sandbox" + \
						" binary. Disabling...\n\n"), noiselevel=-1)
				if "sandbox" in self.features:
					self.features.remove("sandbox")
				if "usersandbox" in self.features:
					self.features.remove("usersandbox")

			self.features.sort()
			if "gpg" in self.features:
				writemsg(colorize("WARN", "!!! FEATURES=gpg is unmaintained, incomplete and broken. Disabling it."), noiselevel=-1)
				self.features.remove("gpg")
			self["FEATURES"] = " ".join(self.features)
			self.backup_changes("FEATURES")

			self._init_dirs()

		if mycpv:
			self.setcpv(mycpv)

	def _init_dirs(self):
		"""
		Create a few directories that are critical to portage operation
		"""
		if not os.access(self["ROOT"], os.W_OK):
			return

		#                                     gid, mode, mask, preserve_perms
		dir_mode_map = {
			"tmp"             : (                      -1, 01777,  0,  True),
			"var/tmp"         : (                      -1, 01777,  0,  True),
			PRIVATE_PATH      : (             portage_gid, 02750, 02,  False),
			CACHE_PATH.lstrip(os.path.sep) : (portage_gid,  0755, 02,  False)
		}

		for mypath, (gid, mode, modemask, preserve_perms) \
			in dir_mode_map.iteritems():
			mydir = os.path.join(self["ROOT"], mypath)
			if preserve_perms and os.path.isdir(mydir):
				# Only adjust permissions on some directories if
				# they don't exist yet. This gives freedom to the
				# user to adjust permissions to suit their taste.
				continue
			try:
				portage.util.ensure_dirs(mydir, gid=gid, mode=mode, mask=modemask)
			except portage.exception.PortageException, e:
				writemsg("!!! Directory initialization failed: '%s'\n" % mydir,
					noiselevel=-1)
				writemsg("!!! %s\n" % str(e),
					noiselevel=-1)

	def expandLicenseTokens(self, tokens):
		""" Take a token from ACCEPT_LICENSE or package.license and expand it
		if it's a group token (indicated by @) or just return it if it's not a
		group.  If a group is negated then negate all group elements."""
		expanded_tokens = []
		for x in tokens:
			expanded_tokens.extend(self._expandLicenseToken(x, None))
		return expanded_tokens

	def _expandLicenseToken(self, token, traversed_groups):
		negate = False
		rValue = []
		if token.startswith("-"):
			negate = True
			license_name = token[1:]
		else:
			license_name = token
		if not license_name.startswith("@"):
			rValue.append(token)
			return rValue
		group_name = license_name[1:]
		if not traversed_groups:
			traversed_groups = set()
		license_group = self._license_groups.get(group_name)
		if group_name in traversed_groups:
			writemsg(("Circular license group reference" + \
				" detected in '%s'\n") % group_name, noiselevel=-1)
			rValue.append("@"+group_name)
		elif license_group:
			traversed_groups.add(group_name)
			for l in license_group:
				if l.startswith("-"):
					writemsg(("Skipping invalid element %s" + \
						" in license group '%s'\n") % (l, group_name),
						noiselevel=-1)
				else:
					rValue.extend(self._expandLicenseToken(l, traversed_groups))
		else:
			writemsg("Undefined license group '%s'\n" % group_name,
				noiselevel=-1)
			rValue.append("@"+group_name)
		if negate:
			rValue = ["-" + token for token in rValue]
		return rValue

	def validate(self):
		"""Validate miscellaneous settings and display warnings if necessary.
		(This code was previously in the global scope of portage.py)"""

		groups = self["ACCEPT_KEYWORDS"].split()
		archlist = self.archlist()
		if not archlist:
			writemsg("--- 'profiles/arch.list' is empty or " + \
				"not available. Empty portage tree?\n", noiselevel=1)
		else:
			for group in groups:
				if group not in archlist and \
					not (group.startswith("-") and group[1:] in archlist) and \
					group not in ("*", "~*", "**"):
					writemsg("!!! INVALID ACCEPT_KEYWORDS: %s\n" % str(group),
						noiselevel=-1)

		abs_profile_path = os.path.join(self["PORTAGE_CONFIGROOT"],
			PROFILE_PATH.lstrip(os.path.sep))
		if not self.profile_path or (not os.path.islink(abs_profile_path) and \
			not os.path.exists(os.path.join(abs_profile_path, "parent")) and \
			os.path.exists(os.path.join(self["PORTDIR"], "profiles"))):
			writemsg("\a\n\n!!! %s is not a symlink and will probably prevent most merges.\n" % abs_profile_path,
				noiselevel=-1)
			writemsg("!!! It should point into a profile within %s/profiles/\n" % self["PORTDIR"])
			writemsg("!!! (You can safely ignore this message when syncing. It's harmless.)\n\n\n")

		abs_user_virtuals = os.path.join(self["PORTAGE_CONFIGROOT"],
			USER_VIRTUALS_FILE.lstrip(os.path.sep))
		if os.path.exists(abs_user_virtuals):
			writemsg("\n!!! /etc/portage/virtuals is deprecated in favor of\n")
			writemsg("!!! /etc/portage/profile/virtuals. Please move it to\n")
			writemsg("!!! this new location.\n\n")

	def loadVirtuals(self,root):
		"""Not currently used by portage."""
		writemsg("DEPRECATED: portage.config.loadVirtuals\n")
		self.getvirtuals(root)

	def load_best_module(self,property_string):
		best_mod = best_from_dict(property_string,self.modules,self.module_priority)
		mod = None
		try:
			mod = load_mod(best_mod)
		except ImportError:
			if best_mod.startswith("cache."):
				best_mod = "portage." + best_mod
				try:
					mod = load_mod(best_mod)
				except ImportError:
					pass
		if mod is None:
			raise
		return mod

	def lock(self):
		self.locked = 1

	def unlock(self):
		self.locked = 0

	def modifying(self):
		if self.locked:
			raise Exception("Configuration is locked.")

	def backup_changes(self,key=None):
		self.modifying()
		if key and key in self.configdict["env"]:
			self.backupenv[key] = copy.deepcopy(self.configdict["env"][key])
		else:
			raise KeyError("No such key defined in environment: %s" % key)

	def reset(self,keeping_pkg=0,use_cache=1):
		"""
		Restore environment from self.backupenv, call self.regenerate()
		@param keeping_pkg: Should we keep the set_cpv() data or delete it.
		@type keeping_pkg: Boolean
		@param use_cache: Should self.regenerate use the cache or not
		@type use_cache: Boolean
		@rype: None
		"""
		self.modifying()
		self.configdict["env"].clear()
		self.configdict["env"].update(self.backupenv)

		self.modifiedkeys = []
		if not keeping_pkg:
			self.mycpv = None
			self.puse = ""
			self.configdict["pkg"].clear()
			self.configdict["pkginternal"].clear()
			self.configdict["defaults"]["USE"] = \
				" ".join(self.make_defaults_use)
			self.usemask  = set(stack_lists(
				self.usemask_list, incremental=True))
			self.useforce  = set(stack_lists(
				self.useforce_list, incremental=True))
		self.regenerate(use_cache=use_cache)

	def load_infodir(self,infodir):
		self.modifying()
		backup_pkg_metadata = dict(self.configdict["pkg"].iteritems())
		if "pkg" in self.configdict and \
			"CATEGORY" in self.configdict["pkg"]:
			self.configdict["pkg"].clear()
			self.configdict["pkg"]["CATEGORY"] = \
				backup_pkg_metadata["CATEGORY"]
		else:
			raise portage.exception.PortageException(
				"No pkg setup for settings instance?")

		retval = 0
		found_category_file = False
		if os.path.isdir(infodir):
			if os.path.exists(infodir+"/environment"):
				self.configdict["pkg"]["PORT_ENV_FILE"] = infodir+"/environment"

			myre = re.compile('^[A-Z]+$')
			null_byte = "\0"
			for filename in listdir(infodir,filesonly=1,EmptyOnError=1):
				if filename == "FEATURES":
					# FEATURES from the build host shouldn't be interpreted as
					# FEATURES on the client system.
					continue
				if filename == "CATEGORY":
					found_category_file = True
					continue
				if myre.match(filename):
					try:
						file_path = os.path.join(infodir, filename)
						mydata = open(file_path).read().strip()
						if len(mydata) < 2048 or filename == "USE":
							if null_byte in mydata:
								writemsg("!!! Null byte found in metadata " + \
									"file: '%s'\n" % file_path, noiselevel=-1)
								continue
							if filename == "USE":
								binpkg_flags = "-* " + mydata
								self.configdict["pkg"][filename] = binpkg_flags
								self.configdict["env"][filename] = mydata
							else:
								self.configdict["pkg"][filename] = mydata
								self.configdict["env"][filename] = mydata
					except (OSError, IOError):
						writemsg("!!! Unable to read file: %s\n" % infodir+"/"+filename,
							noiselevel=-1)
						pass
			retval = 1

		# Missing or corrupt CATEGORY will cause problems for
		# doebuild(), which uses it to infer the cpv. We already
		# know the category, so there's no need to trust this
		# file. Show a warning if the file is missing though,
		# because it's required (especially for binary packages).
		if not found_category_file:
			writemsg("!!! CATEGORY file is missing: %s\n" % \
				os.path.join(infodir, "CATEGORY"), noiselevel=-1)
			self.configdict["pkg"].update(backup_pkg_metadata)
			retval = 0

		# Always set known good values for these variables, since
		# corruption of these can cause problems:
		cat, pf = catsplit(self.mycpv)
		self.configdict["pkg"]["CATEGORY"] = cat
		self.configdict["pkg"]["PF"] = pf

		return retval

	def setcpv(self, mycpv, use_cache=1, mydb=None):
		"""
		Load a particular CPV into the config, this lets us see the
		Default USE flags for a particular ebuild as well as the USE
		flags from package.use.

		@param mycpv: A cpv to load
		@type mycpv: string
		@param use_cache: Enables caching
		@type use_cache: Boolean
		@param mydb: a dbapi instance that supports aux_get with the IUSE key.
		@type mydb: dbapi or derivative.
		@rtype: None
		"""

		self.modifying()

		pkg = None
		if not isinstance(mycpv, basestring):
			pkg = mycpv
			mycpv = pkg.cpv
			mydb = pkg.metadata

		if self.mycpv == mycpv:
			return
		ebuild_phase = self.get("EBUILD_PHASE")
		has_changed = False
		self.mycpv = mycpv
		cp = dep_getkey(mycpv)
		cpv_slot = self.mycpv
		pkginternaluse = ""
		iuse = ""
		if mydb:
			if not hasattr(mydb, "aux_get"):
				slot = mydb["SLOT"]
				iuse = mydb["IUSE"]
			else:
				slot, iuse = mydb.aux_get(self.mycpv, ["SLOT", "IUSE"])
			if pkg is None:
				cpv_slot = "%s:%s" % (self.mycpv, slot)
			else:
				cpv_slot = pkg
			pkginternaluse = []
			for x in iuse.split():
				if x.startswith("+"):
					pkginternaluse.append(x[1:])
				elif x.startswith("-"):
					pkginternaluse.append(x)
			pkginternaluse = " ".join(pkginternaluse)
		if pkginternaluse != self.configdict["pkginternal"].get("USE", ""):
			self.configdict["pkginternal"]["USE"] = pkginternaluse
			has_changed = True
		defaults = []
		pos = 0
		for i in xrange(len(self.profiles)):
			cpdict = self.pkgprofileuse[i].get(cp, None)
			if cpdict:
				keys = cpdict.keys()
				while keys:
					bestmatch = best_match_to_list(cpv_slot, keys)
					if bestmatch:
						keys.remove(bestmatch)
						defaults.insert(pos, cpdict[bestmatch])
					else:
						break
				del keys
			if self.make_defaults_use[i]:
				defaults.insert(pos, self.make_defaults_use[i])
			pos = len(defaults)
		defaults = " ".join(defaults)
		if defaults != self.configdict["defaults"].get("USE",""):
			self.configdict["defaults"]["USE"] = defaults
			has_changed = True
		useforce = []
		pos = 0
		for i in xrange(len(self.profiles)):
			cpdict = self.puseforce_list[i].get(cp, None)
			if cpdict:
				keys = cpdict.keys()
				while keys:
					best_match = best_match_to_list(cpv_slot, keys)
					if best_match:
						keys.remove(best_match)
						useforce.insert(pos, cpdict[best_match])
					else:
						break
				del keys
			if self.useforce_list[i]:
				useforce.insert(pos, self.useforce_list[i])
			pos = len(useforce)
		useforce = set(stack_lists(useforce, incremental=True))
		if useforce != self.useforce:
			self.useforce = useforce
			has_changed = True
		usemask = []
		pos = 0
		for i in xrange(len(self.profiles)):
			cpdict = self.pusemask_list[i].get(cp, None)
			if cpdict:
				keys = cpdict.keys()
				while keys:
					best_match = best_match_to_list(cpv_slot, keys)
					if best_match:
						keys.remove(best_match)
						usemask.insert(pos, cpdict[best_match])
					else:
						break
				del keys
			if self.usemask_list[i]:
				usemask.insert(pos, self.usemask_list[i])
			pos = len(usemask)
		usemask = set(stack_lists(usemask, incremental=True))
		if usemask != self.usemask:
			self.usemask = usemask
			has_changed = True
		oldpuse = self.puse
		self.puse = ""
		cpdict = self.pusedict.get(cp)
		if cpdict:
			keys = cpdict.keys()
			while keys:
				self.pusekey = best_match_to_list(cpv_slot, keys)
				if self.pusekey:
					keys.remove(self.pusekey)
					self.puse = (" ".join(cpdict[self.pusekey])) + " " + self.puse
				else:
					break
			del keys
		if oldpuse != self.puse:
			has_changed = True
		self.configdict["pkg"]["PKGUSE"] = self.puse[:] # For saving to PUSE file
		self.configdict["pkg"]["USE"]    = self.puse[:] # this gets appended to USE
		previous_iuse = self.configdict["pkg"].get("IUSE")
		self.configdict["pkg"]["IUSE"] = iuse

		# Always set known good values for these variables, since
		# corruption of these can cause problems:
		cat, pf = catsplit(self.mycpv)
		self.configdict["pkg"]["CATEGORY"] = cat
		self.configdict["pkg"]["PF"] = pf

		if has_changed:
			self.reset(keeping_pkg=1,use_cache=use_cache)

		# If this is not an ebuild phase and reset() has not been called,
		# it's safe to return early here if IUSE has not changed.
		if not (has_changed or ebuild_phase) and \
			previous_iuse == iuse:
			return

		# Filter out USE flags that aren't part of IUSE. This has to
		# be done for every setcpv() call since practically every
		# package has different IUSE.
		use = set(self["USE"].split())
		iuse_implicit = self._get_implicit_iuse()
		iuse_implicit.update(x.lstrip("+-") for x in iuse.split())

		# Escape anything except ".*" which is supposed
		# to pass through from _get_implicit_iuse()
		regex = sorted(re.escape(x) for x in iuse_implicit)
		regex = "^(%s)$" % "|".join(regex)
		regex = regex.replace("\\.\\*", ".*")
		self.configdict["pkg"]["PORTAGE_IUSE"] = regex

		ebuild_force_test = self.get("EBUILD_FORCE_TEST") == "1"
		if ebuild_force_test and ebuild_phase and \
			not hasattr(self, "_ebuild_force_test_msg_shown"):
				self._ebuild_force_test_msg_shown = True
				writemsg("Forcing test.\n", noiselevel=-1)
		if "test" in self.features and "test" in iuse_implicit:
			if "test" in self.usemask and not ebuild_force_test:
				# "test" is in IUSE and USE=test is masked, so execution
				# of src_test() probably is not reliable. Therefore,
				# temporarily disable FEATURES=test just for this package.
				self["FEATURES"] = " ".join(x for x in self.features \
					if x != "test")
				use.discard("test")
			else:
				use.add("test")
				if ebuild_force_test:
					self.usemask.discard("test")

		# Use the calculated USE flags to regenerate the USE_EXPAND flags so
		# that they are consistent. For optimal performance, use slice
		# comparison instead of startswith().
		use_expand = self.get("USE_EXPAND", "").split()
		for var in use_expand:
			prefix = var.lower() + "_"
			prefix_len = len(prefix)
			expand_flags = set([ x[prefix_len:] for x in use \
				if x[:prefix_len] == prefix ])
			var_split = self.get(var, "").split()
			# Preserve the order of var_split because it can matter for things
			# like LINGUAS.
			var_split = [ x for x in var_split if x in expand_flags ]
			var_split.extend(expand_flags.difference(var_split))
			has_wildcard = "*" in var_split
			if has_wildcard:
				var_split = [ x for x in var_split if x != "*" ]
			has_iuse = set()
			for x in iuse_implicit:
				if x[:prefix_len] == prefix:
					has_iuse.add(x[prefix_len:])
			if has_wildcard:
				# * means to enable everything in IUSE that's not masked
				if has_iuse:
					for x in iuse_implicit:
						if x[:prefix_len] == prefix and x not in self.usemask:
							suffix = x[prefix_len:]
							var_split.append(suffix)
							use.add(x)
				else:
					# If there is a wildcard and no matching flags in IUSE then
					# LINGUAS should be unset so that all .mo files are
					# installed.
					var_split = []
			# Make the flags unique and filter them according to IUSE.
			# Also, continue to preserve order for things like LINGUAS
			# and filter any duplicates that variable may contain.
			filtered_var_split = []
			remaining = has_iuse.intersection(var_split)
			for x in var_split:
				if x in remaining:
					remaining.remove(x)
					filtered_var_split.append(x)
			var_split = filtered_var_split

			if var_split:
				self[var] = " ".join(var_split)
			else:
				# Don't export empty USE_EXPAND vars unless the user config
				# exports them as empty.  This is required for vars such as
				# LINGUAS, where unset and empty have different meanings.
				if has_wildcard:
					# ebuild.sh will see this and unset the variable so
					# that things like LINGUAS work properly
					self[var] = "*"
				else:
					if has_iuse:
						self[var] = ""
					else:
						# It's not in IUSE, so just allow the variable content
						# to pass through if it is defined somewhere.  This
						# allows packages that support LINGUAS but don't
						# declare it in IUSE to use the variable outside of the
						# USE_EXPAND context.
						pass

		# Filtered for the ebuild environment. Store this in a separate
		# attribute since we still want to be able to see global USE
		# settings for things like emerge --info.

		self.configdict["pkg"]["PORTAGE_USE"] = " ".join(sorted(
			x for x in use if \
			x in iuse_implicit))

	def _get_implicit_iuse(self):
		"""
		Some flags are considered to
		be implicit members of IUSE:
		  * Flags derived from ARCH
		  * Flags derived from USE_EXPAND_HIDDEN variables
		  * Masked flags, such as those from {,package}use.mask
		  * Forced flags, such as those from {,package}use.force
		  * build and bootstrap flags used by bootstrap.sh
		"""
		iuse_implicit = set()
		# Flags derived from ARCH.
		arch = self.configdict["defaults"].get("ARCH")
		if arch:
			iuse_implicit.add(arch)
		iuse_implicit.update(self.get("PORTAGE_ARCHLIST", "").split())

		# Flags derived from USE_EXPAND_HIDDEN variables
		# such as ELIBC, KERNEL, and USERLAND.
		use_expand_hidden = self.get("USE_EXPAND_HIDDEN", "").split()
		for x in use_expand_hidden:
			iuse_implicit.add(x.lower() + "_.*")

		# Flags that have been masked or forced.
		iuse_implicit.update(self.usemask)
		iuse_implicit.update(self.useforce)

		# build and bootstrap flags used by bootstrap.sh
		iuse_implicit.add("build")
		iuse_implicit.add("bootstrap")
		return iuse_implicit

	def _getMaskAtom(self, cpv, metadata):
		"""
		Take a package and return a matching package.mask atom, or None if no
		such atom exists or it has been cancelled by package.unmask. PROVIDE
		is not checked, so atoms will not be found for old-style virtuals.

		@param cpv: The package name
		@type cpv: String
		@param metadata: A dictionary of raw package metadata
		@type metadata: dict
		@rtype: String
		@return: An matching atom string or None if one is not found.
		"""

		cp = cpv_getkey(cpv)
		mask_atoms = self.pmaskdict.get(cp)
		if mask_atoms:
			pkg_list = ["%s:%s" % (cpv, metadata["SLOT"])]
			unmask_atoms = self.punmaskdict.get(cp)
			for x in mask_atoms:
				if not match_from_list(x, pkg_list):
					continue
				if unmask_atoms:
					for y in unmask_atoms:
						if match_from_list(y, pkg_list):
							return None
				return x
		return None

	def _getProfileMaskAtom(self, cpv, metadata):
		"""
		Take a package and return a matching profile atom, or None if no
		such atom exists. Note that a profile atom may or may not have a "*"
		prefix. PROVIDE is not checked, so atoms will not be found for
		old-style virtuals.

		@param cpv: The package name
		@type cpv: String
		@param metadata: A dictionary of raw package metadata
		@type metadata: dict
		@rtype: String
		@return: An matching profile atom string or None if one is not found.
		"""

		cp = cpv_getkey(cpv)
		profile_atoms = self.prevmaskdict.get(cp)
		if profile_atoms:
			pkg_list = ["%s:%s" % (cpv, metadata["SLOT"])]
			for x in profile_atoms:
				if match_from_list(x.lstrip("*"), pkg_list):
					continue
				return x
		return None

	def _getMissingKeywords(self, cpv, metadata):
		"""
		Take a package and return a list of any KEYWORDS that the user may
		may need to accept for the given package. If the KEYWORDS are empty
		and the the ** keyword has not been accepted, the returned list will
		contain ** alone (in order to distiguish from the case of "none
		missing").

		@param cpv: The package name (for package.keywords support)
		@type cpv: String
		@param metadata: A dictionary of raw package metadata
		@type metadata: dict
		@rtype: List
		@return: A list of KEYWORDS that have not been accepted.
		"""

		# Hack: Need to check the env directly here as otherwise stacking 
		# doesn't work properly as negative values are lost in the config
		# object (bug #139600)
		egroups = self.configdict["backupenv"].get(
			"ACCEPT_KEYWORDS", "").split()
		mygroups = metadata["KEYWORDS"].split()
		# Repoman may modify this attribute as necessary.
		pgroups = self["ACCEPT_KEYWORDS"].split()
		match=0
		cp = dep_getkey(cpv)
		pkgdict = self.pkeywordsdict.get(cp)
		matches = False
		if pkgdict:
			cpv_slot_list = ["%s:%s" % (cpv, metadata["SLOT"])]
			for atom, pkgkeywords in pkgdict.iteritems():
				if match_from_list(atom, cpv_slot_list):
					matches = True
					pgroups.extend(pkgkeywords)
		if matches or egroups:
			pgroups.extend(egroups)
			inc_pgroups = set()
			for x in pgroups:
				if x.startswith("-"):
					if x == "-*":
						inc_pgroups.clear()
					else:
						inc_pgroups.discard(x[1:])
				else:
					inc_pgroups.add(x)
			pgroups = inc_pgroups
			del inc_pgroups
		hasstable = False
		hastesting = False
		for gp in mygroups:
			if gp == "*" or (gp == "-*" and len(mygroups) == 1):
				writemsg(("--- WARNING: Package '%s' uses" + \
					" '%s' keyword.\n") % (cpv, gp), noiselevel=-1)
				if gp == "*":
					match = 1
					break
			elif gp in pgroups:
				match=1
				break
			elif gp.startswith("~"):
				hastesting = True
			elif not gp.startswith("-"):
				hasstable = True
		if not match and \
			((hastesting and "~*" in pgroups) or \
			(hasstable and "*" in pgroups) or "**" in pgroups):
			match=1
		if match:
			missing = []
		else:
			if not mygroups:
				# If KEYWORDS is empty then we still have to return something
				# in order to distiguish from the case of "none missing".
				mygroups.append("**")
			missing = mygroups
		return missing

	def _getMissingLicenses(self, cpv, metadata):
		"""
		Take a LICENSE string and return a list any licenses that the user may
		may need to accept for the given package.  The returned list will not
		contain any licenses that have already been accepted.  This method
		can throw an InvalidDependString exception.

		@param cpv: The package name (for package.license support)
		@type cpv: String
		@param metadata: A dictionary of raw package metadata
		@type metadata: dict
		@rtype: List
		@return: A list of licenses that have not been accepted.
		"""
		if "*" in self._accept_license:
			return []
		acceptable_licenses = self._accept_license
		cpdict = self._plicensedict.get(dep_getkey(cpv), None)
		if cpdict:
			acceptable_licenses = self._accept_license.copy()
			cpv_slot = "%s:%s" % (cpv, metadata["SLOT"])
			for atom in match_to_list(cpv_slot, cpdict.keys()):
				acceptable_licenses.update(cpdict[atom])
		license_struct = portage.dep.paren_reduce(metadata["LICENSE"])
		license_struct = portage.dep.use_reduce(
			license_struct, uselist=metadata["USE"].split())
		license_struct = portage.dep.dep_opconvert(license_struct)
		return self._getMaskedLicenses(license_struct, acceptable_licenses)

	def _getMaskedLicenses(self, license_struct, acceptable_licenses):
		if not license_struct:
			return []
		if license_struct[0] == "||":
			ret = []
			for element in license_struct[1:]:
				if isinstance(element, list):
					if element:
						ret.append(self._getMaskedLicenses(
							element, acceptable_licenses))
						if not ret[-1]:
							return []
				else:
					if element in acceptable_licenses:
						return []
					ret.append(element)
			# Return all masked licenses, since we don't know which combination
			# (if any) the user will decide to unmask.
			return flatten(ret)

		ret = []
		for element in license_struct:
			if isinstance(element, list):
				if element:
					ret.extend(self._getMaskedLicenses(element,
						acceptable_licenses))
			else:
				if element not in acceptable_licenses:
					ret.append(element)
		return ret

	def _accept_chost(self, pkg):
		"""
		@return True if pkg CHOST is accepted, False otherwise.
		"""
		if self._accept_chost_re is None:
			accept_chost = self.get("ACCEPT_CHOSTS", "").split()
			if not accept_chost:
				chost = self.get("CHOST")
				if chost:
					accept_chost.append(chost)
			if not accept_chost:
				self._accept_chost_re = re.compile(".*")
			elif len(accept_chost) == 1:
				try:
					self._accept_chost_re = re.compile(r'^%s$' % accept_chost[0])
				except re.error, e:
					writemsg("!!! Invalid ACCEPT_CHOSTS value: '%s': %s\n" % \
						(accept_chost[0], e), noiselevel=-1)
					self._accept_chost_re = re.compile("^$")
			else:
				try:
					self._accept_chost_re = re.compile(
						r'^(%s)$' % "|".join(accept_chost))
				except re.error, e:
					writemsg("!!! Invalid ACCEPT_CHOSTS value: '%s': %s\n" % \
						(" ".join(accept_chost), e), noiselevel=-1)
					self._accept_chost_re = re.compile("^$")

		return self._accept_chost_re.match(
			pkg.metadata.get("CHOST", "")) is not None

	def setinst(self,mycpv,mydbapi):
		"""This updates the preferences for old-style virtuals,
		affecting the behavior of dep_expand() and dep_check()
		calls. It can change dbapi.match() behavior since that
		calls dep_expand(). However, dbapi instances have
		internal match caches that are not invalidated when
		preferences are updated here. This can potentially
		lead to some inconsistency (relevant to bug #1343)."""
		self.modifying()
		if len(self.virtuals) == 0:
			self.getvirtuals()
		# Grab the virtuals this package provides and add them into the tree virtuals.
		if not hasattr(mydbapi, "aux_get"):
			provides = mydbapi["PROVIDE"]
		else:
			provides = mydbapi.aux_get(mycpv, ["PROVIDE"])[0]
		if not provides:
			return
		if isinstance(mydbapi, portdbapi):
			self.setcpv(mycpv, mydb=mydbapi)
			myuse = self["PORTAGE_USE"]
		elif not hasattr(mydbapi, "aux_get"):
			myuse = mydbapi["USE"]
		else:
			myuse = mydbapi.aux_get(mycpv, ["USE"])[0]
		virts = flatten(portage.dep.use_reduce(portage.dep.paren_reduce(provides), uselist=myuse.split()))

		modified = False
		cp = dep_getkey(mycpv)
		for virt in virts:
			virt = dep_getkey(virt)
			providers = self.virtuals.get(virt)
			if providers and cp in providers:
				continue
			providers = self._depgraphVirtuals.get(virt)
			if providers is None:
				providers = []
				self._depgraphVirtuals[virt] = providers
			if cp not in providers:
				providers.append(cp)
				modified = True

		if modified:
			self.virtuals = self.__getvirtuals_compile()

	def reload(self):
		"""Reload things like /etc/profile.env that can change during runtime."""
		env_d_filename = os.path.join(self["ROOT"], "etc", "profile.env")
		self.configdict["env.d"].clear()
		env_d = getconfig(env_d_filename, expand=False)
		if env_d:
			# env_d will be None if profile.env doesn't exist.
			self.configdict["env.d"].update(env_d)

	def regenerate(self,useonly=0,use_cache=1):
		"""
		Regenerate settings
		This involves regenerating valid USE flags, re-expanding USE_EXPAND flags
		re-stacking USE flags (-flag and -*), as well as any other INCREMENTAL
		variables.  This also updates the env.d configdict; useful in case an ebuild
		changes the environment.

		If FEATURES has already stacked, it is not stacked twice.

		@param useonly: Only regenerate USE flags (not any other incrementals)
		@type useonly: Boolean
		@param use_cache: Enable Caching (only for autouse)
		@type use_cache: Boolean
		@rtype: None
		"""

		self.modifying()
		if self.already_in_regenerate:
			# XXX: THIS REALLY NEEDS TO GET FIXED. autouse() loops.
			writemsg("!!! Looping in regenerate.\n",1)
			return
		else:
			self.already_in_regenerate = 1

		if useonly:
			myincrementals=["USE"]
		else:
			myincrementals = self.incrementals
		myincrementals = set(myincrementals)
		# If self.features exists, it has already been stacked and may have
		# been mutated, so don't stack it again or else any mutations will be
		# reverted.
		if "FEATURES" in myincrementals and hasattr(self, "features"):
			myincrementals.remove("FEATURES")

		if "USE" in myincrementals:
			# Process USE last because it depends on USE_EXPAND which is also
			# an incremental!
			myincrementals.remove("USE")

		for mykey in myincrementals:

			mydbs=self.configlist[:-1]

			myflags=[]
			for curdb in mydbs:
				if mykey not in curdb:
					continue
				#variables are already expanded
				mysplit = curdb[mykey].split()

				for x in mysplit:
					if x=="-*":
						# "-*" is a special "minus" var that means "unset all settings".
						# so USE="-* gnome" will have *just* gnome enabled.
						myflags = []
						continue

					if x[0]=="+":
						# Not legal. People assume too much. Complain.
						writemsg(red("USE flags should not start with a '+': %s\n" % x),
							noiselevel=-1)
						x=x[1:]
						if not x:
							continue

					if (x[0]=="-"):
						if (x[1:] in myflags):
							# Unset/Remove it.
							del myflags[myflags.index(x[1:])]
						continue

					# We got here, so add it now.
					if x not in myflags:
						myflags.append(x)

			myflags.sort()
			#store setting in last element of configlist, the original environment:
			if myflags or mykey in self:
				self.configlist[-1][mykey] = " ".join(myflags)
			del myflags