diff --git a/src/allmydata/client.py b/src/allmydata/client.py
index 64b09c076..42c2ff384 100644
--- a/src/allmydata/client.py
+++ b/src/allmydata/client.py
@@ -16,6 +16,7 @@ from allmydata.control import ControlServer
 from allmydata.introducer.client import IntroducerClient
 from allmydata.util import hashutil, base32, pollmixin, log, keyutil, idlib
 from allmydata.util.encodingutil import get_filesystem_encoding
+from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.util.abbreviate import parse_abbreviated_size
 from allmydata.util.time_format import parse_duration, parse_date
 from allmydata.stats import StatsProvider
@@ -450,8 +451,8 @@ class Client(node.Node, pollmixin.PollMixin):
 
         from allmydata.webish import WebishServer
         nodeurl_path = os.path.join(self.basedir, "node.url")
-        staticdir = self.get_config("node", "web.static", "public_html")
-        staticdir = os.path.expanduser(staticdir)
+        staticdir_config = self.get_config("node", "web.static", "public_html").decode("utf-8")
+        staticdir = abspath_expanduser_unicode(staticdir_config, base=self.basedir)
         ws = WebishServer(self, webport, nodeurl_path, staticdir)
         self.add_service(ws)
 
diff --git a/src/allmydata/frontends/auth.py b/src/allmydata/frontends/auth.py
index fa7fd3794..712a888a0 100644
--- a/src/allmydata/frontends/auth.py
+++ b/src/allmydata/frontends/auth.py
@@ -1,4 +1,5 @@
 import os
+
 from zope.interface import implements
 from twisted.web.client import getPage
 from twisted.internet import defer
@@ -7,6 +8,8 @@ from twisted.conch import error as conch_error
 from twisted.conch.ssh import keys
 
 from allmydata.util import base32
+from allmydata.util.fileutil import abspath_expanduser_unicode
+
 
 class NeedRootcapLookupScheme(Exception):
     """Accountname+Password-based access schemes require some kind of
@@ -28,7 +31,7 @@ class AccountFileChecker:
         self.passwords = {}
         self.pubkeys = {}
         self.rootcaps = {}
-        for line in open(os.path.expanduser(accountfile), "r"):
+        for line in open(abspath_expanduser_unicode(accountfile), "r"):
             line = line.strip()
             if line.startswith("#") or not line:
                 continue
diff --git a/src/allmydata/frontends/drop_upload.py b/src/allmydata/frontends/drop_upload.py
index 6f25625e0..0e2b48b49 100644
--- a/src/allmydata/frontends/drop_upload.py
+++ b/src/allmydata/frontends/drop_upload.py
@@ -1,5 +1,5 @@
 
-import os, sys
+import sys
 
 from twisted.internet import defer
 from twisted.python.filepath import FilePath
@@ -9,6 +9,7 @@ from foolscap.api import eventually
 from allmydata.interfaces import IDirectoryNode
 
 from allmydata.util.encodingutil import quote_output, get_filesystem_encoding
+from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.immutable.upload import FileName
 
 
@@ -19,7 +20,7 @@ class DropUploader(service.MultiService):
         service.MultiService.__init__(self)
 
         try:
-            local_dir_u = os.path.expanduser(local_dir_utf8.decode('utf-8'))
+            local_dir_u = abspath_expanduser_unicode(local_dir_utf8.decode('utf-8'))
             if sys.platform == "win32":
                 local_dir = local_dir_u
             else:
diff --git a/src/allmydata/introducer/server.py b/src/allmydata/introducer/server.py
index 43a026114..7031c3af6 100644
--- a/src/allmydata/introducer/server.py
+++ b/src/allmydata/introducer/server.py
@@ -6,7 +6,7 @@ from foolscap.api import Referenceable
 import allmydata
 from allmydata import node
 from allmydata.util import log, rrefutil
-from allmydata.util.encodingutil import get_filesystem_encoding
+from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.introducer.interfaces import \
      RIIntroducerPublisherAndSubscriberService_v2
 from allmydata.introducer.common import convert_announcement_v1_to_v2, \
@@ -21,7 +21,7 @@ class IntroducerNode(node.Node):
     NODETYPE = "introducer"
     GENERATED_FILES = ['introducer.furl']
 
-    def __init__(self, basedir="."):
+    def __init__(self, basedir=u"."):
         node.Node.__init__(self, basedir)
         self.read_config()
         self.init_introducer()
@@ -33,8 +33,8 @@ class IntroducerNode(node.Node):
         introducerservice = IntroducerService(self.basedir)
         self.add_service(introducerservice)
 
-        old_public_fn = os.path.join(self.basedir, "introducer.furl").encode(get_filesystem_encoding())
-        private_fn = os.path.join(self.basedir, "private", "introducer.furl").encode(get_filesystem_encoding())
+        old_public_fn = os.path.join(self.basedir, u"introducer.furl")
+        private_fn = os.path.join(self.basedir, u"private", u"introducer.furl")
 
         if os.path.exists(old_public_fn):
             if os.path.exists(private_fn):
@@ -62,9 +62,9 @@ class IntroducerNode(node.Node):
         self.log("init_web(webport=%s)", args=(webport,), umid="2bUygA")
 
         from allmydata.webish import IntroducerWebishServer
-        nodeurl_path = os.path.join(self.basedir, "node.url")
-        staticdir = self.get_config("node", "web.static", "public_html")
-        staticdir = os.path.expanduser(staticdir)
+        nodeurl_path = os.path.join(self.basedir, u"node.url")
+        config_staticdir = self.get_config("node", "web.static", "public_html").decode('utf-8')
+        staticdir = abspath_expanduser_unicode(config_staticdir, base=self.basedir)
         ws = IntroducerWebishServer(self, webport, nodeurl_path, staticdir)
         self.add_service(ws)
 
diff --git a/src/allmydata/manhole.py b/src/allmydata/manhole.py
index 1d6121dc0..63b62a545 100644
--- a/src/allmydata/manhole.py
+++ b/src/allmydata/manhole.py
@@ -1,8 +1,8 @@
 
 # this is adapted from my code in Buildbot  -warner
 
-import os.path
 import binascii, base64
+
 from twisted.python import log
 from twisted.application import service, strports
 from twisted.cred import checkers, portal
@@ -12,6 +12,8 @@ from twisted.internet import protocol
 
 from zope.interface import implements
 
+from allmydata.util.fileutil import precondition_abspath
+
 # makeTelnetProtocol and _TelnetRealm are for the TelnetManhole
 
 class makeTelnetProtocol:
@@ -63,7 +65,8 @@ class AuthorizedKeysChecker(conchc.SSHPublicKeyDatabase):
     """
 
     def __init__(self, authorized_keys_file):
-        self.authorized_keys_file = os.path.expanduser(authorized_keys_file)
+        precondition_abspath(authorized_keys_file)
+        self.authorized_keys_file = authorized_keys_file
 
     def checkKey(self, credentials):
         f = open(self.authorized_keys_file)
@@ -244,14 +247,12 @@ class AuthorizedKeysManhole(_BaseManhole):
         'tcp:12345:interface=127.0.0.1'. Bare integers are treated as a
         simple tcp port.
 
-        @param keyfile: the name of a file (relative to the buildmaster's
-                        basedir) that contains SSH public keys of authorized
-                        users, one per line. This is the exact same format
-                        as used by sshd in ~/.ssh/authorized_keys .
+        @param keyfile: the path of a file that contains SSH public keys of
+                        authorized users, one per line. This is the exact
+                        same format as used by sshd in ~/.ssh/authorized_keys .
+                        The path should be absolute.
         """
 
-        # TODO: expanduser this, and make it relative to the buildmaster's
-        # basedir
         self.keyfile = keyfile
         c = AuthorizedKeysChecker(keyfile)
         _BaseManhole.__init__(self, port, c)
diff --git a/src/allmydata/node.py b/src/allmydata/node.py
index d29ad22ce..710ce7d50 100644
--- a/src/allmydata/node.py
+++ b/src/allmydata/node.py
@@ -93,12 +93,11 @@ class Node(service.MultiService):
         iputil.increase_rlimits()
 
     def init_tempdir(self):
-        local_tempdir_utf8 = "tmp" # default is NODEDIR/tmp/
-        tempdir = self.get_config("node", "tempdir", local_tempdir_utf8).decode('utf-8')
-        tempdir = os.path.join(self.basedir, tempdir)
+        tempdir_config = self.get_config("node", "tempdir", "tmp").decode('utf-8')
+        tempdir = abspath_expanduser_unicode(tempdir_config, base=self.basedir)
         if not os.path.exists(tempdir):
             fileutil.make_dirs(tempdir)
-        tempfile.tempdir = abspath_expanduser_unicode(tempdir)
+        tempfile.tempdir = tempdir
         # this should cause twisted.web.http (which uses
         # tempfile.TemporaryFile) to put large request bodies in the given
         # directory. Without this, the default temp dir is usually /tmp/,
@@ -220,11 +219,12 @@ class Node(service.MultiService):
     def setup_ssh(self):
         ssh_port = self.get_config("node", "ssh.port", "")
         if ssh_port:
-            ssh_keyfile = self.get_config("node", "ssh.authorized_keys_file").decode('utf-8')
+            ssh_keyfile_config = self.get_config("node", "ssh.authorized_keys_file").decode('utf-8')
+            ssh_keyfile = abspath_expanduser_unicode(ssh_keyfile_config, base=self.basedir)
             from allmydata import manhole
-            m = manhole.AuthorizedKeysManhole(ssh_port, ssh_keyfile.encode(get_filesystem_encoding()))
+            m = manhole.AuthorizedKeysManhole(ssh_port, ssh_keyfile)
             m.setServiceParent(self)
-            self.log("AuthorizedKeysManhole listening on %s" % ssh_port)
+            self.log("AuthorizedKeysManhole listening on %s" % (ssh_port,))
 
     def get_app_versions(self):
         # TODO: merge this with allmydata.get_package_versions
diff --git a/src/allmydata/scripts/cli.py b/src/allmydata/scripts/cli.py
index b0e4e6dec..e240c9ecd 100644
--- a/src/allmydata/scripts/cli.py
+++ b/src/allmydata/scripts/cli.py
@@ -2,7 +2,7 @@ import os.path, re, fnmatch
 from twisted.python import usage
 from allmydata.scripts.common import get_aliases, get_default_nodedir, \
      DEFAULT_ALIAS, BaseOptions
-from allmydata.util.encodingutil import argv_to_unicode, argv_to_abspath, quote_output
+from allmydata.util.encodingutil import argv_to_unicode, argv_to_abspath, quote_local_unicode_path
 
 NODEURL_RE=re.compile("http(s?)://([^:]*)(:([1-9][0-9]*))?")
 
@@ -140,15 +140,11 @@ class GetOptions(FilesystemOptions):
         # tahoe get FOO bar              # write to local file
         # tahoe get tahoe:FOO bar        # same
 
+        if arg2 == "-":
+            arg2 = None
+
         self.from_file = argv_to_unicode(arg1)
-
-        if arg2:
-            self.to_file = argv_to_unicode(arg2)
-        else:
-            self.to_file = None
-
-        if self.to_file == "-":
-            self.to_file = None
+        self.to_file   = None if arg2 is None else argv_to_abspath(arg2)
 
     def getSynopsis(self):
         return "Usage:  %s [global-opts] get [options] REMOTE_FILE LOCAL_FILE" % (self.command_name,)
@@ -180,17 +176,11 @@ class PutOptions(FilesystemOptions):
     def parseArgs(self, arg1=None, arg2=None):
         # see Examples below
 
-        if arg1 is not None and arg2 is not None:
-            self.from_file = argv_to_unicode(arg1)
-            self.to_file =  argv_to_unicode(arg2)
-        elif arg1 is not None and arg2 is None:
-            self.from_file = argv_to_unicode(arg1) # might be "-"
-            self.to_file = None
-        else:
-            self.from_file = None
-            self.to_file = None
-        if self.from_file == u"-":
-            self.from_file = None
+        if arg1 == "-":
+            arg1 = None
+
+        self.from_file = None if arg1 is None else argv_to_abspath(arg1)
+        self.to_file   = None if arg2 is None else argv_to_unicode(arg2)
 
         if self['format']:
             if self['format'].upper() not in ("SDMF", "MDMF", "CHK"):
@@ -347,7 +337,7 @@ class BackupOptions(FilesystemOptions):
         self['exclude'] = set()
 
     def parseArgs(self, localdir, topath):
-        self.from_dir = argv_to_unicode(localdir)
+        self.from_dir = argv_to_abspath(localdir)
         self.to_dir = argv_to_unicode(topath)
 
     def getSynopsis(self):
@@ -368,7 +358,7 @@ class BackupOptions(FilesystemOptions):
         try:
             exclude_file = file(abs_filepath)
         except:
-            raise BackupConfigurationError('Error opening exclude file %s.' % quote_output(abs_filepath))
+            raise BackupConfigurationError('Error opening exclude file %s.' % quote_local_unicode_path(abs_filepath))
         try:
             for line in exclude_file:
                 self.opt_exclude(line)
diff --git a/src/allmydata/scripts/common.py b/src/allmydata/scripts/common.py
index 21481e35d..55cb3f08c 100644
--- a/src/allmydata/scripts/common.py
+++ b/src/allmydata/scripts/common.py
@@ -3,7 +3,8 @@ import os, sys, urllib
 import codecs
 from twisted.python import usage
 from allmydata.util.assertutil import precondition
-from allmydata.util.encodingutil import unicode_to_url, quote_output, argv_to_abspath
+from allmydata.util.encodingutil import unicode_to_url, quote_output, \
+    quote_local_unicode_path, argv_to_abspath
 from allmydata.util.fileutil import abspath_expanduser_unicode
 
 
@@ -40,7 +41,7 @@ class BasedirOptions(BaseOptions):
 
     optParameters = [
         ["basedir", "C", None, "Specify which Tahoe base directory should be used. [default: %s]"
-         % get_default_nodedir()],
+         % quote_local_unicode_path(_default_nodedir)],
     ]
 
     def parseArgs(self, basedir=None):
@@ -196,5 +197,6 @@ def get_alias(aliases, path_unicode, default):
     return uri.from_string_dirnode(aliases[alias]).to_string(), path[colon+1:]
 
 def escape_path(path):
+    # this always returns bytes, specifically US-ASCII, valid URL characters
     segments = path.split("/")
     return "/".join([urllib.quote(unicode_to_url(s)) for s in segments])
diff --git a/src/allmydata/scripts/debug.py b/src/allmydata/scripts/debug.py
index 8ef82eca9..fedd69851 100644
--- a/src/allmydata/scripts/debug.py
+++ b/src/allmydata/scripts/debug.py
@@ -645,15 +645,15 @@ def find_shares(options):
     /home/warner/testnet/node-2/storage/shares/44k/44kai1tui348689nrw8fjegc8c/2
     """
     from allmydata.storage.server import si_a2b, storage_index_to_dir
-    from allmydata.util.encodingutil import listdir_unicode
+    from allmydata.util.encodingutil import listdir_unicode, quote_local_unicode_path
 
     out = options.stdout
     sharedir = storage_index_to_dir(si_a2b(options.si_s))
     for d in options.nodedirs:
-        d = os.path.join(d, "storage/shares", sharedir)
+        d = os.path.join(d, "storage", "shares", sharedir)
         if os.path.exists(d):
             for shnum in listdir_unicode(d):
-                print >>out, os.path.join(d, shnum)
+                print >>out, quote_local_unicode_path(os.path.join(d, shnum), quotemarks=False)
 
     return 0
 
@@ -832,7 +832,7 @@ def catalog_shares(options):
     err = options.stderr
     now = time.time()
     for d in options.nodedirs:
-        d = os.path.join(d, "storage/shares")
+        d = os.path.join(d, "storage", "shares")
         try:
             abbrevs = listdir_unicode(d)
         except EnvironmentError:
diff --git a/src/allmydata/scripts/runner.py b/src/allmydata/scripts/runner.py
index 085967079..1a6de258e 100644
--- a/src/allmydata/scripts/runner.py
+++ b/src/allmydata/scripts/runner.py
@@ -6,7 +6,7 @@ from twisted.python import usage
 
 from allmydata.scripts.common import get_default_nodedir
 from allmydata.scripts import debug, create_node, startstop_node, cli, keygen, stats_gatherer, admin
-from allmydata.util.encodingutil import quote_output, get_io_encoding
+from allmydata.util.encodingutil import quote_output, quote_local_unicode_path, get_io_encoding
 
 def GROUP(s):
     # Usage.parseOptions compares argv[1] against command[0], so it will
@@ -25,7 +25,7 @@ NODEDIR_HELP = ("Specify which Tahoe node directory should be used. The "
                 "' which contains the mapping from alias name to root "
                 "dirnode URI.")
 if _default_nodedir:
-    NODEDIR_HELP += " [default for most commands: " + quote_output(_default_nodedir) + "]"
+    NODEDIR_HELP += " [default for most commands: " + quote_local_unicode_path(_default_nodedir) + "]"
 
 class Options(usage.Options):
     # unit tests can override these to point at StringIO instances
diff --git a/src/allmydata/scripts/startstop_node.py b/src/allmydata/scripts/startstop_node.py
index 09cdc9373..45b7fd112 100644
--- a/src/allmydata/scripts/startstop_node.py
+++ b/src/allmydata/scripts/startstop_node.py
@@ -4,7 +4,7 @@ from allmydata.scripts.common import BasedirOptions
 from twisted.scripts import twistd
 from twisted.python import usage
 from allmydata.util import fileutil
-from allmydata.util.encodingutil import listdir_unicode, quote_output
+from allmydata.util.encodingutil import listdir_unicode, quote_local_unicode_path
 
 
 class StartOptions(BasedirOptions):
@@ -92,13 +92,14 @@ def identify_node_type(basedir):
 
 def start(config, out=sys.stdout, err=sys.stderr):
     basedir = config['basedir']
-    print >>out, "STARTING", quote_output(basedir)
+    quoted_basedir = quote_local_unicode_path(basedir)
+    print >>out, "STARTING", quoted_basedir
     if not os.path.isdir(basedir):
-        print >>err, "%s does not look like a directory at all" % quote_output(basedir)
+        print >>err, "%s does not look like a directory at all" % quoted_basedir
         return 1
     nodetype = identify_node_type(basedir)
     if not nodetype:
-        print >>err, "%s is not a recognizable node directory" % quote_output(basedir)
+        print >>err, "%s is not a recognizable node directory" % quoted_basedir
         return 1
     # Now prepare to turn into a twistd process. This os.chdir is the point
     # of no return.
@@ -108,7 +109,7 @@ def start(config, out=sys.stdout, err=sys.stderr):
         and "--nodaemon" not in config.twistd_args
         and "--syslog" not in config.twistd_args
         and "--logfile" not in config.twistd_args):
-        fileutil.make_dirs(os.path.join(basedir, "logs"))
+        fileutil.make_dirs(os.path.join(basedir, u"logs"))
         twistd_args.extend(["--logfile", os.path.join("logs", "twistd.log")])
     twistd_args.extend(config.twistd_args)
     twistd_args.append("StartTahoeNode") # point at our StartTahoeNodePlugin
@@ -154,17 +155,18 @@ def start(config, out=sys.stdout, err=sys.stderr):
     else:
         verb = "starting"
 
-    print >>out, "%s node in %s" % (verb, basedir)
+    print >>out, "%s node in %s" % (verb, quoted_basedir)
     twistd.runApp(twistd_config)
     # we should only reach here if --nodaemon or equivalent was used
     return 0
 
 def stop(config, out=sys.stdout, err=sys.stderr):
     basedir = config['basedir']
-    print >>out, "STOPPING", quote_output(basedir)
-    pidfile = os.path.join(basedir, "twistd.pid")
+    quoted_basedir = quote_local_unicode_path(basedir)
+    print >>out, "STOPPING", quoted_basedir
+    pidfile = os.path.join(basedir, u"twistd.pid")
     if not os.path.exists(pidfile):
-        print >>err, "%s does not look like a running node directory (no twistd.pid)" % quote_output(basedir)
+        print >>err, "%s does not look like a running node directory (no twistd.pid)" % quoted_basedir
         # we define rc=2 to mean "nothing is running, but it wasn't me who
         # stopped it"
         return 2
diff --git a/src/allmydata/scripts/tahoe_backup.py b/src/allmydata/scripts/tahoe_backup.py
index ef3da34b4..f12b31713 100644
--- a/src/allmydata/scripts/tahoe_backup.py
+++ b/src/allmydata/scripts/tahoe_backup.py
@@ -10,9 +10,9 @@ from allmydata.scripts.common_http import do_http, HTTPError, format_http_error
 from allmydata.util import time_format
 from allmydata.scripts import backupdb
 from allmydata.util.encodingutil import listdir_unicode, quote_output, \
-     to_str, FilenameEncodingError, unicode_to_url
+     quote_local_unicode_path, to_str, FilenameEncodingError, unicode_to_url
 from allmydata.util.assertutil import precondition
-from allmydata.util.fileutil import abspath_expanduser_unicode
+from allmydata.util.fileutil import abspath_expanduser_unicode, precondition_abspath
 
 
 def get_local_metadata(path):
@@ -160,10 +160,11 @@ class BackerUpper:
         print >>self.options.stderr, msg
 
     def process(self, localpath):
-        precondition(isinstance(localpath, unicode), localpath)
+        precondition_abspath(localpath)
         # returns newdircap
 
-        self.verboseprint("processing %s" % quote_output(localpath))
+        quoted_path = quote_local_unicode_path(localpath)
+        self.verboseprint("processing %s" % (quoted_path,))
         create_contents = {} # childname -> (type, rocap, metadata)
         compare_contents = {} # childname -> rocap
 
@@ -171,11 +172,11 @@ class BackerUpper:
             children = listdir_unicode(localpath)
         except EnvironmentError:
             self.directories_skipped += 1
-            self.warn("WARNING: permission denied on directory %s" % quote_output(localpath))
+            self.warn("WARNING: permission denied on directory %s" % (quoted_path,))
             children = []
         except FilenameEncodingError:
             self.directories_skipped += 1
-            self.warn("WARNING: could not list directory %s due to a filename encoding error" % quote_output(localpath))
+            self.warn("WARNING: could not list directory %s due to a filename encoding error" % (quoted_path,))
             children = []
 
         for child in self.options.filter_listdir(children):
@@ -197,17 +198,17 @@ class BackerUpper:
                     compare_contents[child] = childcap
                 except EnvironmentError:
                     self.files_skipped += 1
-                    self.warn("WARNING: permission denied on file %s" % quote_output(childpath))
+                    self.warn("WARNING: permission denied on file %s" % quote_local_unicode_path(childpath))
             else:
                 self.files_skipped += 1
                 if os.path.islink(childpath):
-                    self.warn("WARNING: cannot backup symlink %s" % quote_output(childpath))
+                    self.warn("WARNING: cannot backup symlink %s" % quote_local_unicode_path(childpath))
                 else:
-                    self.warn("WARNING: cannot backup special file %s" % quote_output(childpath))
+                    self.warn("WARNING: cannot backup special file %s" % quote_local_unicode_path(childpath))
 
         must_create, r = self.check_backupdb_directory(compare_contents)
         if must_create:
-            self.verboseprint(" creating directory for %s" % quote_output(localpath))
+            self.verboseprint(" creating directory for %s" % quote_local_unicode_path(localpath))
             newdircap = mkdir(create_contents, self.options)
             assert isinstance(newdircap, str)
             if r:
@@ -215,7 +216,7 @@ class BackerUpper:
             self.directories_created += 1
             return newdircap
         else:
-            self.verboseprint(" re-using old directory for %s" % quote_output(localpath))
+            self.verboseprint(" re-using old directory for %s" % quote_local_unicode_path(localpath))
             self.directories_reused += 1
             return r.was_created()
 
@@ -288,16 +289,16 @@ class BackerUpper:
 
     # This function will raise an IOError exception when called on an unreadable file
     def upload(self, childpath):
-        precondition(isinstance(childpath, unicode), childpath)
+        precondition_abspath(childpath)
 
-        #self.verboseprint("uploading %s.." % quote_output(childpath))
+        #self.verboseprint("uploading %s.." % quote_local_unicode_path(childpath))
         metadata = get_local_metadata(childpath)
 
         # we can use the backupdb here
         must_upload, bdb_results = self.check_backupdb_file(childpath)
 
         if must_upload:
-            self.verboseprint("uploading %s.." % quote_output(childpath))
+            self.verboseprint("uploading %s.." % quote_local_unicode_path(childpath))
             infileobj = open(childpath, "rb")
             url = self.options['node-url'] + "uri"
             resp = do_http("PUT", url, infileobj)
@@ -305,7 +306,7 @@ class BackerUpper:
                 raise HTTPError("Error during file PUT", resp)
 
             filecap = resp.read().strip()
-            self.verboseprint(" %s -> %s" % (quote_output(childpath, quotemarks=False),
+            self.verboseprint(" %s -> %s" % (quote_local_unicode_path(childpath, quotemarks=False),
                                              quote_output(filecap, quotemarks=False)))
             #self.verboseprint(" metadata: %s" % (quote_output(metadata, quotemarks=False),))
 
@@ -316,7 +317,7 @@ class BackerUpper:
             return filecap, metadata
 
         else:
-            self.verboseprint("skipping %s.." % quote_output(childpath))
+            self.verboseprint("skipping %s.." % quote_local_unicode_path(childpath))
             self.files_reused += 1
             return bdb_results.was_uploaded(), metadata
 
diff --git a/src/allmydata/scripts/tahoe_cp.py b/src/allmydata/scripts/tahoe_cp.py
index 965aa26f3..756db5bae 100644
--- a/src/allmydata/scripts/tahoe_cp.py
+++ b/src/allmydata/scripts/tahoe_cp.py
@@ -9,14 +9,15 @@ from allmydata.scripts.common import get_alias, escape_path, \
 from allmydata.scripts.common_http import do_http, HTTPError
 from allmydata import uri
 from allmydata.util import fileutil
-from allmydata.util.fileutil import abspath_expanduser_unicode
-from allmydata.util.encodingutil import unicode_to_url, listdir_unicode, quote_output, to_str
+from allmydata.util.fileutil import abspath_expanduser_unicode, precondition_abspath
+from allmydata.util.encodingutil import unicode_to_url, listdir_unicode, quote_output, \
+    quote_local_unicode_path, to_str
 from allmydata.util.assertutil import precondition
 
 
 class MissingSourceError(TahoeError):
-    def __init__(self, name):
-        TahoeError.__init__(self, "No such file or directory %s" % quote_output(name))
+    def __init__(self, name, quotefn=quote_output):
+        TahoeError.__init__(self, "No such file or directory %s" % quotefn(name))
 
 
 def GET_to_file(url):
@@ -61,37 +62,34 @@ def make_tahoe_subdirectory(nodeurl, parent_writecap, name):
 
 class LocalFileSource:
     def __init__(self, pathname):
-        precondition(isinstance(pathname, unicode), pathname)
+        precondition_abspath(pathname)
         self.pathname = pathname
 
     def need_to_copy_bytes(self):
         return True
 
     def open(self, caps_only):
-        return open(os.path.expanduser(self.pathname), "rb")
-
+        return open(self.pathname, "rb")
 
 class LocalFileTarget:
     def __init__(self, pathname):
-        precondition(isinstance(pathname, unicode), pathname)
+        precondition_abspath(pathname)
         self.pathname = pathname
 
     def put_file(self, inf):
         fileutil.put_file(self.pathname, inf)
 
-
 class LocalMissingTarget:
     def __init__(self, pathname):
-        precondition(isinstance(pathname, unicode), pathname)
+        precondition_abspath(pathname)
         self.pathname = pathname
 
     def put_file(self, inf):
         fileutil.put_file(self.pathname, inf)
 
-
 class LocalDirectorySource:
     def __init__(self, progressfunc, pathname):
-        precondition(isinstance(pathname, unicode), pathname)
+        precondition_abspath(pathname)
 
         self.progressfunc = progressfunc
         self.pathname = pathname
@@ -119,7 +117,7 @@ class LocalDirectorySource:
 
 class LocalDirectoryTarget:
     def __init__(self, progressfunc, pathname):
-        precondition(isinstance(pathname, unicode), pathname)
+        precondition_abspath(pathname)
 
         self.progressfunc = progressfunc
         self.pathname = pathname
@@ -132,7 +130,6 @@ class LocalDirectoryTarget:
         children = listdir_unicode(self.pathname)
         for i,n in enumerate(children):
             self.progressfunc("examining %d of %d" % (i+1, len(children)))
-            n = unicode(n)
             pn = os.path.join(self.pathname, n)
             if os.path.isdir(pn):
                 child = LocalDirectoryTarget(self.progressfunc, pn)
@@ -144,6 +141,7 @@ class LocalDirectoryTarget:
                 self.children[n] = LocalFileTarget(pn)
 
     def get_child_target(self, name):
+        precondition(isinstance(name, unicode), name)
         if self.children is None:
             self.populate(False)
         if name in self.children:
@@ -160,6 +158,7 @@ class LocalDirectoryTarget:
     def set_children(self):
         pass
 
+
 class TahoeFileSource:
     def __init__(self, nodeurl, mutable, writecap, readcap):
         self.nodeurl = nodeurl
@@ -371,6 +370,7 @@ class TahoeDirectoryTarget:
 
     def get_child_target(self, name):
         # return a new target for a named subdirectory of this dir
+        precondition(isinstance(name, unicode), name)
         if self.children is None:
             self.populate(False)
         if name in self.children:
@@ -383,6 +383,7 @@ class TahoeDirectoryTarget:
         return child
 
     def put_file(self, name, inf):
+        precondition(isinstance(name, unicode), name)
         url = self.nodeurl + "uri"
         if not hasattr(inf, "seek"):
             inf = inf.read()
@@ -402,6 +403,7 @@ class TahoeDirectoryTarget:
             self.new_children[name] = filecap
 
     def put_uri(self, name, filecap):
+        precondition(isinstance(name, unicode), name)
         self.new_children[name] = filecap
 
     def set_children(self):
@@ -518,16 +520,23 @@ class Copier:
     def to_stderr(self, text):
         print >>self.stderr, text
 
+    # FIXME reduce the amount of near-duplicate code between get_target_info
+    # and get_source_info.
+
     def get_target_info(self, destination_spec):
-        rootcap, path = get_alias(self.aliases, destination_spec, None)
+        precondition(isinstance(destination_spec, unicode), destination_spec)
+        rootcap, path_utf8 = get_alias(self.aliases, destination_spec, None)
+        path = path_utf8.decode("utf-8")
         if rootcap == DefaultAliasMarker:
             # no alias, so this is a local file
-            pathname = abspath_expanduser_unicode(path.decode('utf-8'))
+            pathname = abspath_expanduser_unicode(path)
             if not os.path.exists(pathname):
                 t = LocalMissingTarget(pathname)
             elif os.path.isdir(pathname):
                 t = LocalDirectoryTarget(self.progress, pathname)
             else:
+                # TODO: should this be _assert? what happens if the target is
+                # a special file?
                 assert os.path.isfile(pathname), pathname
                 t = LocalFileTarget(pathname) # non-empty
         else:
@@ -559,13 +568,15 @@ class Copier:
         return t
 
     def get_source_info(self, source_spec):
-        rootcap, path = get_alias(self.aliases, source_spec, None)
+        precondition(isinstance(source_spec, unicode), source_spec)
+        rootcap, path_utf8 = get_alias(self.aliases, source_spec, None)
+        path = path_utf8.decode("utf-8")
         if rootcap == DefaultAliasMarker:
             # no alias, so this is a local file
-            pathname = abspath_expanduser_unicode(path.decode('utf-8'))
+            pathname = abspath_expanduser_unicode(path)
             name = os.path.basename(pathname)
             if not os.path.exists(pathname):
-                raise MissingSourceError(source_spec)
+                raise MissingSourceError(source_spec, quotefn=quote_local_unicode_path)
             if os.path.isdir(pathname):
                 t = LocalDirectorySource(self.progress, pathname)
             else:
@@ -577,9 +588,9 @@ class Copier:
             name = None
             if path:
                 url += "/" + escape_path(path)
-                last_slash = path.rfind("/")
+                last_slash = path.rfind(u"/")
                 name = path
-                if last_slash:
+                if last_slash != -1:
                     name = path[last_slash+1:]
 
             resp = do_http("GET", url + "?t=json")
@@ -598,8 +609,13 @@ class Copier:
                 writecap = to_str(d.get("rw_uri"))
                 readcap = to_str(d.get("ro_uri"))
                 mutable = d.get("mutable", False) # older nodes don't provide it
-                if source_spec.rfind('/') != -1:
-                    name = source_spec[source_spec.rfind('/')+1:]
+
+                last_slash = source_spec.rfind(u"/")
+                if last_slash != -1:
+                    # TODO: this looks funny and redundant with the 'name'
+                    # assignment above. cf #2329
+                    name = source_spec[last_slash+1:]
+
                 t = TahoeFileSource(self.nodeurl, mutable, writecap, readcap)
         return name, t
 
@@ -679,6 +695,7 @@ class Copier:
         return self.announce_success("files copied")
 
     def attach_to_target(self, source, name, target):
+        precondition(isinstance(name, unicode), name)
         if target not in self.targetmap:
             self.targetmap[target] = {}
         self.targetmap[target][name] = source
@@ -686,7 +703,7 @@ class Copier:
 
     def assign_targets(self, source, target):
         # copy everything in the source into the target
-        assert isinstance(source, (LocalDirectorySource, TahoeDirectorySource))
+        precondition(isinstance(source, (LocalDirectorySource, TahoeDirectorySource)), source)
 
         for name, child in source.children.items():
             if isinstance(child, (LocalDirectorySource, TahoeDirectorySource)):
@@ -694,14 +711,12 @@ class Copier:
                 subtarget = target.get_child_target(name)
                 self.assign_targets(child, subtarget)
             else:
-                assert isinstance(child, (LocalFileSource, TahoeFileSource))
+                precondition(isinstance(child, (LocalFileSource, TahoeFileSource)), child)
                 self.attach_to_target(child, name, target)
 
-
-
     def copy_files_to_target(self, targetmap, target):
         for name, source in targetmap.items():
-            assert isinstance(source, (LocalFileSource, TahoeFileSource))
+            precondition(isinstance(source, (LocalFileSource, TahoeFileSource)), source)
             self.copy_file_into(source, name, target)
             self.files_copied += 1
             self.progress("%d/%d files, %d/%d directories" %
@@ -723,9 +738,9 @@ class Copier:
         return 0
 
     def copy_file(self, source, target):
-        assert isinstance(source, (LocalFileSource, TahoeFileSource))
-        assert isinstance(target, (LocalFileTarget, TahoeFileTarget,
-                                   LocalMissingTarget, TahoeMissingTarget))
+        precondition(isinstance(source, (LocalFileSource, TahoeFileSource)), source)
+        precondition(isinstance(target, (LocalFileTarget, TahoeFileTarget,
+                                         LocalMissingTarget, TahoeMissingTarget)), target)
         if self.need_to_copy_bytes(source, target):
             # if the target is a local directory, this will just write the
             # bytes to disk. If it is a tahoe directory, it will upload the
@@ -740,8 +755,9 @@ class Copier:
         return self.announce_success("file linked")
 
     def copy_file_into(self, source, name, target):
-        assert isinstance(source, (LocalFileSource, TahoeFileSource))
-        assert isinstance(target, (LocalDirectoryTarget, TahoeDirectoryTarget))
+        precondition(isinstance(source, (LocalFileSource, TahoeFileSource)), source)
+        precondition(isinstance(target, (LocalDirectoryTarget, TahoeDirectoryTarget)), target)
+        precondition(isinstance(name, unicode), name)
         if self.need_to_copy_bytes(source, target):
             # if the target is a local directory, this will just write the
             # bytes to disk. If it is a tahoe directory, it will upload the
diff --git a/src/allmydata/scripts/tahoe_get.py b/src/allmydata/scripts/tahoe_get.py
index 280d8c052..73ef67b45 100644
--- a/src/allmydata/scripts/tahoe_get.py
+++ b/src/allmydata/scripts/tahoe_get.py
@@ -1,5 +1,5 @@
 
-import os, urllib
+import urllib
 from allmydata.scripts.common import get_alias, DEFAULT_ALIAS, escape_path, \
                                      UnknownAliasError
 from allmydata.scripts.common_http import do_http, format_http_error
@@ -26,7 +26,7 @@ def get(options):
     resp = do_http("GET", url)
     if resp.status in (200, 201,):
         if to_file:
-            outf = open(os.path.expanduser(to_file), "wb")
+            outf = open(to_file, "wb")
         else:
             outf = stdout
         while True:
diff --git a/src/allmydata/scripts/tahoe_put.py b/src/allmydata/scripts/tahoe_put.py
index a85539efe..91b71c814 100644
--- a/src/allmydata/scripts/tahoe_put.py
+++ b/src/allmydata/scripts/tahoe_put.py
@@ -1,7 +1,7 @@
 
-import os
 from cStringIO import StringIO
 import urllib
+
 from allmydata.scripts.common_http import do_http, format_http_success, format_http_error
 from allmydata.scripts.common import get_alias, DEFAULT_ALIAS, escape_path, \
                                      UnknownAliasError
@@ -73,7 +73,7 @@ def put(options):
         url += "?" + "&".join(queryargs)
 
     if from_file:
-        infileobj = open(os.path.expanduser(from_file), "rb")
+        infileobj = open(from_file, "rb")
     else:
         # do_http() can't use stdin directly: for one thing, we need a
         # Content-Length field. So we currently must copy it.
diff --git a/src/allmydata/stats.py b/src/allmydata/stats.py
index 7db323ba5..22f018124 100644
--- a/src/allmydata/stats.py
+++ b/src/allmydata/stats.py
@@ -11,8 +11,8 @@ from twisted.application.internet import TimerService
 from zope.interface import implements
 from foolscap.api import eventually, DeadReferenceError, Referenceable, Tub
 
-from allmydata.util import log
-from allmydata.util.encodingutil import quote_output
+from allmydata.util import log, fileutil
+from allmydata.util.encodingutil import quote_local_unicode_path
 from allmydata.interfaces import RIStatsProvider, RIStatsGatherer, IStatsProducer
 
 class LoadMonitor(service.MultiService):
@@ -246,7 +246,7 @@ class StdOutStatsGatherer(StatsGatherer):
 class PickleStatsGatherer(StdOutStatsGatherer):
     # inherit from StdOutStatsGatherer for connect/disconnect notifications
 
-    def __init__(self, basedir=".", verbose=True):
+    def __init__(self, basedir=u".", verbose=True):
         self.verbose = verbose
         StatsGatherer.__init__(self, basedir)
         self.picklefile = os.path.join(basedir, "stats.pickle")
@@ -258,7 +258,7 @@ class PickleStatsGatherer(StdOutStatsGatherer):
             except Exception:
                 print ("Error while attempting to load pickle file %s.\n"
                        "You may need to restore this file from a backup, or delete it if no backup is available.\n" %
-                       quote_output(os.path.abspath(self.picklefile)))
+                       quote_local_unicode_path(self.picklefile))
                 raise
             f.close()
         else:
@@ -311,7 +311,7 @@ class StatsGathererService(service.MultiService):
     def save_portnum(self, junk):
         portnum = self.listener.getPortnum()
         portnumfile = os.path.join(self.basedir, 'portnum')
-        open(portnumfile, 'wb').write('%d\n' % (portnum,))
+        fileutil.write(portnumfile, '%d\n' % (portnum,))
 
     def tub_ready(self, ignored):
         ff = os.path.join(self.basedir, self.furl_file)
diff --git a/src/allmydata/test/test_auth.py b/src/allmydata/test/test_auth.py
index b61531b1b..2b52f00af 100644
--- a/src/allmydata/test/test_auth.py
+++ b/src/allmydata/test/test_auth.py
@@ -5,6 +5,8 @@ from twisted.conch import error as conch_error
 from twisted.conch.ssh import keys
 
 from allmydata.frontends import auth
+from allmydata.util.fileutil import abspath_expanduser_unicode
+
 
 DUMMY_KEY = keys.Key.fromString("""\
 -----BEGIN RSA PRIVATE KEY-----
@@ -37,7 +39,8 @@ class AccountFileCheckerKeyTests(unittest.TestCase):
     def setUp(self):
         self.account_file = filepath.FilePath(self.mktemp())
         self.account_file.setContent(DUMMY_ACCOUNTS)
-        self.checker = auth.AccountFileChecker(None, self.account_file.path)
+        abspath = abspath_expanduser_unicode(unicode(self.account_file.path))
+        self.checker = auth.AccountFileChecker(None, abspath)
 
     def test_unknown_user(self):
         """
diff --git a/src/allmydata/test/test_cli.py b/src/allmydata/test/test_cli.py
index 6bc5fc1c6..b39cafc49 100644
--- a/src/allmydata/test/test_cli.py
+++ b/src/allmydata/test/test_cli.py
@@ -2509,6 +2509,28 @@ starting copy, 2 files, 1 directories
         d.addCallback(_check_local_fs)
         return d
 
+    def test_ticket_2027(self):
+        # This test ensures that tahoe will copy a file from the grid to
+        # a local directory without a specified file name.
+        # https://tahoe-lafs.org/trac/tahoe-lafs/ticket/2027
+        self.basedir = "cli/Cp/cp_verbose"
+        self.set_up_grid()
+
+        # Write a test file, which we'll copy to the grid.
+        test1_path = os.path.join(self.basedir, "test1")
+        fileutil.write(test1_path, "test1")
+
+        d = self.do_cli("create-alias", "tahoe")
+        d.addCallback(lambda ign:
+            self.do_cli("cp", test1_path, "tahoe:"))
+        d.addCallback(lambda ign:
+            self.do_cli("cp", "tahoe:test1", self.basedir))
+        def _check(res):
+            (rc, out, err) = res
+            self.failUnlessIn("Success: file copied", out, str(res))
+        return d
+
+
 class Backup(GridTestMixin, CLITestMixin, StallMixin, unittest.TestCase):
 
     def writeto(self, path, data):
@@ -2854,7 +2876,8 @@ class Backup(GridTestMixin, CLITestMixin, StallMixin, unittest.TestCase):
         def _check((rc, out, err)):
             self.failUnlessReallyEqual(rc, 2)
             foo2 = os.path.join(source, "foo2.txt")
-            self.failUnlessReallyEqual(err, "WARNING: cannot backup symlink '%s'\n" % foo2)
+            self.failUnlessIn("WARNING: cannot backup symlink ", err)
+            self.failUnlessIn(foo2, err)
 
             fu, fr, fs, dc, dr, ds = self.count_output(out)
             # foo.txt
@@ -3779,7 +3802,7 @@ class Webopen(GridTestMixin, CLITestMixin, unittest.TestCase):
             raise
         return d
 
-class Options(unittest.TestCase):
+class Options(ReallyEqualMixin, unittest.TestCase):
     # this test case only looks at argument-processing and simple stuff.
 
     def parse(self, args, stdout=None):
@@ -3861,17 +3884,17 @@ class Options(unittest.TestCase):
         # option after, or a basedir argument after, but none in the wrong
         # place, and not more than one of the three.
         o = self.parse(["start"])
-        self.failUnlessEqual(o["basedir"], os.path.join(os.path.expanduser("~"),
-                                                        ".tahoe"))
+        self.failUnlessReallyEqual(o["basedir"], os.path.join(fileutil.abspath_expanduser_unicode(u"~"),
+                                                              u".tahoe"))
         o = self.parse(["start", "here"])
-        self.failUnlessEqual(o["basedir"], os.path.abspath("here"))
+        self.failUnlessReallyEqual(o["basedir"], fileutil.abspath_expanduser_unicode(u"here"))
         o = self.parse(["start", "--basedir", "there"])
-        self.failUnlessEqual(o["basedir"], os.path.abspath("there"))
+        self.failUnlessReallyEqual(o["basedir"], fileutil.abspath_expanduser_unicode(u"there"))
         o = self.parse(["--node-directory", "there", "start"])
-        self.failUnlessEqual(o["basedir"], os.path.abspath("there"))
+        self.failUnlessReallyEqual(o["basedir"], fileutil.abspath_expanduser_unicode(u"there"))
 
         o = self.parse(["start", "here", "--nodaemon"])
-        self.failUnlessEqual(o["basedir"], os.path.abspath("here"))
+        self.failUnlessReallyEqual(o["basedir"], fileutil.abspath_expanduser_unicode(u"here"))
 
         self.failUnlessRaises(usage.UsageError, self.parse,
                               ["--basedir", "there", "start"])
diff --git a/src/allmydata/test/test_client.py b/src/allmydata/test/test_client.py
index 531215f61..94bfbdf53 100644
--- a/src/allmydata/test/test_client.py
+++ b/src/allmydata/test/test_client.py
@@ -1,4 +1,4 @@
-import os
+import os, sys
 from twisted.trial import unittest
 from twisted.application import service
 
@@ -6,6 +6,7 @@ import allmydata
 from allmydata.node import Node, OldConfigError, OldConfigOptionError, MissingConfigEntry, UnescapedHashError
 from allmydata import client
 from allmydata.storage_client import StorageFarmBroker
+from allmydata.manhole import AuthorizedKeysManhole
 from allmydata.util import base32, fileutil
 from allmydata.interfaces import IFilesystemNode, IFileNode, \
      IImmutableFileNode, IMutableFileNode, IDirectoryNode
@@ -68,10 +69,11 @@ class Basic(testutil.ReallyEqualMixin, unittest.TestCase):
         fileutil.write(os.path.join(basedir, "debug_discard_storage"), "")
 
         e = self.failUnlessRaises(OldConfigError, client.Client, basedir)
-        self.failUnlessIn(os.path.abspath(os.path.join(basedir, "introducer.furl")), e.args[0])
-        self.failUnlessIn(os.path.abspath(os.path.join(basedir, "no_storage")), e.args[0])
-        self.failUnlessIn(os.path.abspath(os.path.join(basedir, "readonly_storage")), e.args[0])
-        self.failUnlessIn(os.path.abspath(os.path.join(basedir, "debug_discard_storage")), e.args[0])
+        abs_basedir = fileutil.abspath_expanduser_unicode(unicode(basedir)).encode(sys.getfilesystemencoding())
+        self.failUnlessIn(os.path.join(abs_basedir, "introducer.furl"), e.args[0])
+        self.failUnlessIn(os.path.join(abs_basedir, "no_storage"), e.args[0])
+        self.failUnlessIn(os.path.join(abs_basedir, "readonly_storage"), e.args[0])
+        self.failUnlessIn(os.path.join(abs_basedir, "debug_discard_storage"), e.args[0])
 
         for oldfile in ['introducer.furl', 'no_storage', 'readonly_storage',
                         'debug_discard_storage']:
@@ -173,6 +175,34 @@ class Basic(testutil.ReallyEqualMixin, unittest.TestCase):
                            "reserved_space = bogus\n")
         self.failUnlessRaises(ValueError, client.Client, basedir)
 
+    def test_web_staticdir(self):
+        basedir = u"client.Basic.test_web_staticdir"
+        os.mkdir(basedir)
+        fileutil.write(os.path.join(basedir, "tahoe.cfg"),
+                       BASECONFIG +
+                       "[node]\n" +
+                       "web.port = tcp:0:interface=127.0.0.1\n" +
+                       "web.static = relative\n")
+        c = client.Client(basedir)
+        w = c.getServiceNamed("webish")
+        abs_basedir = fileutil.abspath_expanduser_unicode(basedir)
+        expected = fileutil.abspath_expanduser_unicode(u"relative", abs_basedir)
+        self.failUnlessReallyEqual(w.staticdir, expected)
+
+    def test_manhole_keyfile(self):
+        basedir = u"client.Basic.test_manhole_keyfile"
+        os.mkdir(basedir)
+        fileutil.write(os.path.join(basedir, "tahoe.cfg"),
+                       BASECONFIG +
+                       "[node]\n" +
+                       "ssh.port = tcp:0:interface=127.0.0.1\n" +
+                       "ssh.authorized_keys_file = relative\n")
+        c = client.Client(basedir)
+        m = [s for s in c if isinstance(s, AuthorizedKeysManhole)][0]
+        abs_basedir = fileutil.abspath_expanduser_unicode(basedir)
+        expected = fileutil.abspath_expanduser_unicode(u"relative", abs_basedir)
+        self.failUnlessReallyEqual(m.keyfile, expected)
+
     def _permute(self, sb, key):
         return [ s.get_longname() for s in sb.get_servers_for_psi(key) ]
 
diff --git a/src/allmydata/test/test_encodingutil.py b/src/allmydata/test/test_encodingutil.py
index abd3d8cb5..926c3659d 100644
--- a/src/allmydata/test/test_encodingutil.py
+++ b/src/allmydata/test/test_encodingutil.py
@@ -61,10 +61,11 @@ from mock import patch
 import os, sys, locale
 
 from allmydata.test.common_util import ReallyEqualMixin
-from allmydata.util import encodingutil
+from allmydata.util import encodingutil, fileutil
 from allmydata.util.encodingutil import argv_to_unicode, unicode_to_url, \
-    unicode_to_output, quote_output, unicode_platform, listdir_unicode, \
-    FilenameEncodingError, get_io_encoding, get_filesystem_encoding, _reload
+    unicode_to_output, quote_output, quote_path, quote_local_unicode_path, \
+    unicode_platform, listdir_unicode, FilenameEncodingError, get_io_encoding, \
+    get_filesystem_encoding, _reload
 from allmydata.dirnode import normalize
 
 from twisted.python import usage
@@ -274,8 +275,8 @@ class StdlibUnicode(unittest.TestCase):
         # to lumiere_nfc (on Mac OS X, it will be the NFD equivalent).
         self.failUnlessIn(lumiere_nfc + ".txt", set([normalize(fname) for fname in filenames]))
 
-        expanded = os.path.expanduser("~/" + lumiere_nfc)
-        self.failIfIn("~", expanded)
+        expanded = fileutil.expanduser(u"~/" + lumiere_nfc)
+        self.failIfIn(u"~", expanded)
         self.failUnless(expanded.endswith(lumiere_nfc), expanded)
 
     def test_open_unrepresentable(self):
@@ -395,6 +396,19 @@ class QuoteOutput(ReallyEqualMixin, unittest.TestCase):
         self.test_quote_output_utf8(None)
 
 
+class QuotePaths(ReallyEqualMixin, unittest.TestCase):
+    def test_quote_path(self):
+        self.failUnlessReallyEqual(quote_path([u'foo', u'bar']), "'foo/bar'")
+        self.failUnlessReallyEqual(quote_path([u'foo', u'bar'], quotemarks=True), "'foo/bar'")
+        self.failUnlessReallyEqual(quote_path([u'foo', u'\nbar']), '"foo/\\x0abar"')
+        self.failUnlessReallyEqual(quote_path([u'foo', u'\nbar'], quotemarks=True), '"foo/\\x0abar"')
+
+        self.failUnlessReallyEqual(quote_local_unicode_path(u"\\\\?\\C:\\foo"),
+                                   "'C:\\foo'" if sys.platform == "win32" else "'\\\\?\\C:\\foo'")
+        self.failUnlessReallyEqual(quote_local_unicode_path(u"\\\\?\\UNC\\foo\\bar"),
+                                   "'\\\\foo\\bar'" if sys.platform == "win32" else "'\\\\?\\UNC\\foo\\bar'")
+
+
 class UbuntuKarmicUTF8(EncodingUtil, unittest.TestCase):
     uname = 'Linux korn 2.6.31-14-generic #48-Ubuntu SMP Fri Oct 16 14:05:01 UTC 2009 x86_64'
     argv = 'lumi\xc3\xa8re'
diff --git a/src/allmydata/test/test_introducer.py b/src/allmydata/test/test_introducer.py
index 21adb8140..475b04dba 100644
--- a/src/allmydata/test/test_introducer.py
+++ b/src/allmydata/test/test_introducer.py
@@ -28,7 +28,7 @@ class LoggingMultiService(service.MultiService):
     def log(self, msg, **kw):
         log.msg(msg, **kw)
 
-class Node(testutil.SignalMixin, unittest.TestCase):
+class Node(testutil.SignalMixin, testutil.ReallyEqualMixin, unittest.TestCase):
     def test_furl(self):
         basedir = "introducer.IntroducerNode.test_furl"
         os.mkdir(basedir)
@@ -74,6 +74,20 @@ class Node(testutil.SignalMixin, unittest.TestCase):
         d.addCallback(_check_furl)
         return d
 
+    def test_web_static(self):
+        basedir = u"introducer.Node.test_web_static"
+        os.mkdir(basedir)
+        fileutil.write(os.path.join(basedir, "tahoe.cfg"),
+                       "[node]\n" +
+                       "web.port = tcp:0:interface=127.0.0.1\n" +
+                       "web.static = relative\n")
+        c = IntroducerNode(basedir)
+        w = c.getServiceNamed("webish")
+        abs_basedir = fileutil.abspath_expanduser_unicode(basedir)
+        expected = fileutil.abspath_expanduser_unicode(u"relative", abs_basedir)
+        self.failUnlessReallyEqual(w.staticdir, expected)
+
+
 class ServiceMixin:
     def setUp(self):
         self.parent = LoggingMultiService()
diff --git a/src/allmydata/test/test_mutable.py b/src/allmydata/test/test_mutable.py
index fb39af72e..26c7f244d 100644
--- a/src/allmydata/test/test_mutable.py
+++ b/src/allmydata/test/test_mutable.py
@@ -1,10 +1,13 @@
 import os, re, base64
 from cStringIO import StringIO
+
 from twisted.trial import unittest
 from twisted.internet import defer, reactor
+
 from allmydata import uri, client
 from allmydata.nodemaker import NodeMaker
 from allmydata.util import base32, consumer, fileutil, mathutil
+from allmydata.util.fileutil import abspath_expanduser_unicode
 from allmydata.util.hashutil import tagged_hash, ssk_writekey_hash, \
      ssk_pubkey_fingerprint_hash
 from allmydata.util.consumer import MemoryConsumer
@@ -3110,7 +3113,7 @@ class Version(GridTestMixin, unittest.TestCase, testutil.ShouldFailMixin, \
             fso = debug.FindSharesOptions()
             storage_index = base32.b2a(n.get_storage_index())
             fso.si_s = storage_index
-            fso.nodedirs = [unicode(os.path.dirname(os.path.abspath(storedir)))
+            fso.nodedirs = [os.path.dirname(abspath_expanduser_unicode(unicode(storedir)))
                             for (i,ss,storedir)
                             in self.iterate_servers()]
             fso.stdout = StringIO()
diff --git a/src/allmydata/test/test_util.py b/src/allmydata/test/test_util.py
index 2a5ba1997..d907c118a 100644
--- a/src/allmydata/test/test_util.py
+++ b/src/allmydata/test/test_util.py
@@ -15,6 +15,8 @@ from allmydata.util import limiter, time_format, pollmixin, cachedir
 from allmydata.util import statistics, dictutil, pipeline
 from allmydata.util import log as tahoe_log
 from allmydata.util.spans import Spans, overlap, DataSpans
+from allmydata.test.common_util import ReallyEqualMixin
+
 
 class Base32(unittest.TestCase):
     def test_b2a_matches_Pythons(self):
@@ -370,7 +372,7 @@ class Asserts(unittest.TestCase):
         m = self.should_assert(f, False, othermsg="message2")
         self.failUnlessEqual("postcondition: othermsg: 'message2' <type 'str'>", m)
 
-class FileUtil(unittest.TestCase):
+class FileUtil(ReallyEqualMixin, unittest.TestCase):
     def mkdir(self, basedir, path, mode=0777):
         fn = os.path.join(basedir, path)
         fileutil.make_dirs(fn, mode)
@@ -429,22 +431,6 @@ class FileUtil(unittest.TestCase):
         fileutil.write_atomically(fn, "two", mode="") # non-binary
         self.failUnlessEqual(fileutil.read(fn), "two")
 
-    def test_open_or_create(self):
-        basedir = "util/FileUtil/test_open_or_create"
-        fileutil.make_dirs(basedir)
-        fn = os.path.join(basedir, "here")
-        f = fileutil.open_or_create(fn)
-        f.write("stuff.")
-        f.close()
-        f = fileutil.open_or_create(fn)
-        f.seek(0, os.SEEK_END)
-        f.write("more.")
-        f.close()
-        f = open(fn, "r")
-        data = f.read()
-        f.close()
-        self.failUnlessEqual(data, "stuff.more.")
-
     def test_NamedTemporaryDirectory(self):
         basedir = "util/FileUtil/test_NamedTemporaryDirectory"
         fileutil.make_dirs(basedir)
@@ -488,7 +474,16 @@ class FileUtil(unittest.TestCase):
         abspath_cwd = fileutil.abspath_expanduser_unicode(u".")
         self.failUnless(isinstance(saved_cwd, unicode), saved_cwd)
         self.failUnless(isinstance(abspath_cwd, unicode), abspath_cwd)
-        self.failUnlessEqual(abspath_cwd, saved_cwd)
+        if sys.platform == "win32":
+            self.failUnlessReallyEqual(abspath_cwd, fileutil.to_windows_long_path(saved_cwd))
+        else:
+            self.failUnlessReallyEqual(abspath_cwd, saved_cwd)
+
+        self.failUnlessReallyEqual(fileutil.to_windows_long_path(u"\\\\?\\foo"), u"\\\\?\\foo")
+        self.failUnlessReallyEqual(fileutil.to_windows_long_path(u"\\\\.\\foo"), u"\\\\.\\foo")
+        self.failUnlessReallyEqual(fileutil.to_windows_long_path(u"\\\\server\\foo"), u"\\\\?\\UNC\\server\\foo")
+        self.failUnlessReallyEqual(fileutil.to_windows_long_path(u"C:\\foo"), u"\\\\?\\C:\\foo")
+        self.failUnlessReallyEqual(fileutil.to_windows_long_path(u"C:\\foo/bar"), u"\\\\?\\C:\\foo\\bar")
 
         # adapted from <http://svn.python.org/view/python/branches/release26-maint/Lib/test/test_posixpath.py?view=markup&pathrev=78279#test_abspath>
 
@@ -512,6 +507,34 @@ class FileUtil(unittest.TestCase):
             finally:
                 os.chdir(saved_cwd)
 
+    def test_create_long_path(self):
+        workdir = u"test_create_long_path"
+        fileutil.make_dirs(workdir)
+        long_path = fileutil.abspath_expanduser_unicode(os.path.join(workdir, u'x'*255))
+        def _cleanup():
+            fileutil.remove(long_path)
+        self.addCleanup(_cleanup)
+
+        fileutil.write(long_path, "test")
+        self.failUnless(os.path.exists(long_path))
+        self.failUnlessEqual(fileutil.read(long_path), "test")
+        _cleanup()
+        self.failIf(os.path.exists(long_path))
+
+    def test_windows_expanduser(self):
+        def call_windows_getenv(name):
+            if name == u"HOMEDRIVE": return u"C:"
+            if name == u"HOMEPATH": return u"\\Documents and Settings\\\u0100"
+            self.fail("unexpected argument to call_windows_getenv")
+        self.patch(fileutil, 'windows_getenv', call_windows_getenv)
+
+        self.failUnlessReallyEqual(fileutil.windows_expanduser(u"~"), os.path.join(u"C:", u"\\Documents and Settings\\\u0100"))
+        self.failUnlessReallyEqual(fileutil.windows_expanduser(u"~\\foo"), os.path.join(u"C:", u"\\Documents and Settings\\\u0100", u"foo"))
+        self.failUnlessReallyEqual(fileutil.windows_expanduser(u"~/foo"), os.path.join(u"C:", u"\\Documents and Settings\\\u0100", u"foo"))
+        self.failUnlessReallyEqual(fileutil.windows_expanduser(u"a"), u"a")
+        self.failUnlessReallyEqual(fileutil.windows_expanduser(u"a~"), u"a~")
+        self.failUnlessReallyEqual(fileutil.windows_expanduser(u"a\\~\\foo"), u"a\\~\\foo")
+
     def test_disk_stats(self):
         avail = fileutil.get_available_space('.', 2**14)
         if avail == 0:
diff --git a/src/allmydata/util/encodingutil.py b/src/allmydata/util/encodingutil.py
index 3ceb1a919..feafd8f5c 100644
--- a/src/allmydata/util/encodingutil.py
+++ b/src/allmydata/util/encodingutil.py
@@ -230,6 +230,16 @@ def quote_output(s, quotemarks=True, quote_newlines=None, encoding=None):
 def quote_path(path, quotemarks=True):
     return quote_output("/".join(map(to_str, path)), quotemarks=quotemarks, quote_newlines=True)
 
+def quote_local_unicode_path(path, quotemarks=True):
+    precondition(isinstance(path, unicode), path)
+
+    if sys.platform == "win32" and path.startswith(u"\\\\?\\"):
+        path = path[4 :]
+        if path.startswith(u"UNC\\"):
+            path = u"\\\\" + path[4 :]
+
+    return quote_output(path, quotemarks=quotemarks, quote_newlines=True)
+
 
 def unicode_platform():
     """
diff --git a/src/allmydata/util/fileutil.py b/src/allmydata/util/fileutil.py
index 8eb8e9fb6..7bb25e8e7 100644
--- a/src/allmydata/util/fileutil.py
+++ b/src/allmydata/util/fileutil.py
@@ -224,12 +224,6 @@ def remove_if_possible(f):
     except:
         pass
 
-def open_or_create(fname, binarymode=True):
-    try:
-        return open(fname, binarymode and "r+b" or "r+")
-    except EnvironmentError:
-        return open(fname, binarymode and "w+b" or "w+")
-
 def du(basedir):
     size = 0
 
@@ -269,9 +263,11 @@ def read(path):
     finally:
         rf.close()
 
-def put_file(pathname, inf):
+def put_file(path, inf):
+    precondition_abspath(path)
+
     # TODO: create temporary file and move into place?
-    outf = open(os.path.expanduser(pathname), "wb")
+    outf = open(path, "wb")
     try:
         while True:
             data = inf.read(32768)
@@ -282,6 +278,20 @@ def put_file(pathname, inf):
         outf.close()
 
 
+def precondition_abspath(path):
+    if not isinstance(path, unicode):
+        raise AssertionError("an abspath must be a Unicode string")
+
+    if sys.platform == "win32":
+        # This intentionally doesn't view absolute paths starting with a drive specification, or
+        # paths relative to the current drive, as acceptable.
+        if not path.startswith("\\\\"):
+            raise AssertionError("an abspath should be normalized using abspath_expanduser_unicode")
+    else:
+        # This intentionally doesn't view the path '~' or paths starting with '~/' as acceptable.
+        if not os.path.isabs(path):
+            raise AssertionError("an abspath should be normalized using abspath_expanduser_unicode")
+
 # Work around <http://bugs.python.org/issue3426>. This code is adapted from
 # <http://svn.python.org/view/python/trunk/Lib/ntpath.py?revision=78247&view=markup>
 # with some simplifications.
@@ -292,11 +302,20 @@ try:
 except ImportError:
     pass
 
-def abspath_expanduser_unicode(path):
-    """Return the absolute version of a path."""
-    assert isinstance(path, unicode), path
+def abspath_expanduser_unicode(path, base=None):
+    """
+    Return the absolute version of a path. If 'base' is given and 'path' is relative,
+    the path will be expanded relative to 'base'.
+    'path' must be a Unicode string. 'base', if given, must be a Unicode string
+    corresponding to an absolute path as returned by a previous call to
+    abspath_expanduser_unicode.
+    """
+    if not isinstance(path, unicode):
+        raise AssertionError("paths must be Unicode strings")
+    if base is not None:
+        precondition_abspath(base)
 
-    path = os.path.expanduser(path)
+    path = expanduser(path)
 
     if _getfullpathname:
         # On Windows, os.path.isabs will return True for paths without a drive letter,
@@ -307,19 +326,50 @@ def abspath_expanduser_unicode(path):
             pass
 
     if not os.path.isabs(path):
-        path = os.path.join(os.getcwdu(), path)
+        if base is None:
+            path = os.path.join(os.getcwdu(), path)
+        else:
+            path = os.path.join(base, path)
 
     # We won't hit <http://bugs.python.org/issue5827> because
     # there is always at least one Unicode path component.
-    return os.path.normpath(path)
+    path = os.path.normpath(path)
+
+    if sys.platform == "win32":
+        path = to_windows_long_path(path)
+
+    return path
+
+def to_windows_long_path(path):
+    # '/' is normally a perfectly valid path component separator in Windows.
+    # However, when using the "\\?\" syntax it is not recognized, so we
+    # replace it with '\' here.
+    path = path.replace(u"/", u"\\")
+
+    # Note that other normalizations such as removing '.' and '..' should
+    # be done outside this function.
+
+    if path.startswith(u"\\\\?\\") or path.startswith(u"\\\\.\\"):
+        return path
+    elif path.startswith(u"\\\\"):
+        return u"\\\\?\\UNC\\" + path[2 :]
+    else:
+        return u"\\\\?\\" + path
 
 
 have_GetDiskFreeSpaceExW = False
 if sys.platform == "win32":
-    try:
-        from ctypes import WINFUNCTYPE, windll, POINTER, byref, c_ulonglong
-        from ctypes.wintypes import BOOL, DWORD, LPCWSTR
+    from ctypes import WINFUNCTYPE, windll, POINTER, byref, c_ulonglong, create_unicode_buffer
+    from ctypes.wintypes import BOOL, DWORD, LPCWSTR, LPWSTR
 
+    # <http://msdn.microsoft.com/en-us/library/ms679360%28v=VS.85%29.aspx>
+    GetLastError = WINFUNCTYPE(DWORD)(("GetLastError", windll.kernel32))
+
+    # <http://msdn.microsoft.com/en-us/library/windows/desktop/ms683188%28v=vs.85%29.aspx>
+    GetEnvironmentVariableW = WINFUNCTYPE(DWORD, LPCWSTR, LPWSTR, DWORD)(
+        ("GetEnvironmentVariableW", windll.kernel32))
+
+    try:
         # <http://msdn.microsoft.com/en-us/library/aa383742%28v=VS.85%29.aspx>
         PULARGE_INTEGER = POINTER(c_ulonglong)
 
@@ -327,14 +377,57 @@ if sys.platform == "win32":
         GetDiskFreeSpaceExW = WINFUNCTYPE(BOOL, LPCWSTR, PULARGE_INTEGER, PULARGE_INTEGER, PULARGE_INTEGER)(
             ("GetDiskFreeSpaceExW", windll.kernel32))
 
-        # <http://msdn.microsoft.com/en-us/library/ms679360%28v=VS.85%29.aspx>
-        GetLastError = WINFUNCTYPE(DWORD)(("GetLastError", windll.kernel32))
-
         have_GetDiskFreeSpaceExW = True
     except Exception:
         import traceback
         traceback.print_exc()
 
+def expanduser(path):
+    # os.path.expanduser is hopelessly broken for Unicode paths on Windows (ticket #1674).
+    if sys.platform == "win32":
+        return windows_expanduser(path)
+    else:
+        return os.path.expanduser(path)
+
+def windows_expanduser(path):
+    if not path.startswith('~'):
+        return path
+    home_drive = windows_getenv(u'HOMEDRIVE')
+    home_path = windows_getenv(u'HOMEPATH')
+    if path == '~':
+        return os.path.join(home_drive, home_path)
+    elif path.startswith('~/') or path.startswith('~\\'):
+        return os.path.join(home_drive, home_path, path[2 :])
+    else:
+        return path
+
+def windows_getenv(name):
+    # Based on <http://stackoverflow.com/questions/2608200/problems-with-umlauts-in-python-appdata-environvent-variable/2608368#2608368>,
+    # with improved error handling.
+    if not isinstance(name, unicode):
+        raise AssertionError("name must be Unicode")
+
+    n = GetEnvironmentVariableW(name, None, 0)
+    if n == 0:
+        err = GetLastError()
+        raise OSError("Windows error %d attempting to read size of environment variable %r"
+                      % (err, name))
+    elif n < 0:
+        raise OSError("Unexpected result %d from GetEnvironmentVariableW attempting to read size of environment variable %r"
+                      % (n, name))
+
+    buf = create_unicode_buffer(u'\0'*n)
+    retval = GetEnvironmentVariableW(name, buf, n)
+    if retval == 0:
+        err = GetLastError()
+        raise OSError("Windows error %d attempting to read environment variable %r"
+                      % (err, name))
+    elif retval != n-1:
+        raise OSError("Unexpected result %d from GetEnvironmentVariableW attempting to read environment variable %r"
+                      % (n, name))
+
+    return buf.value
+
 def get_disk_stats(whichdir, reserved_space=0):
     """Return disk statistics for the storage disk, in the form of a dict
     with the following fields.
diff --git a/src/allmydata/webish.py b/src/allmydata/webish.py
index 813856cb0..e2029feec 100644
--- a/src/allmydata/webish.py
+++ b/src/allmydata/webish.py
@@ -147,6 +147,7 @@ class WebishServer(service.MultiService):
         self.site = site = appserver.NevowSite(self.root)
         self.site.requestFactory = MyRequest
         self.site.remember(MyExceptionHandler(), inevow.ICanHandleException)
+        self.staticdir = staticdir # so tests can check
         if staticdir:
             self.root.putChild("static", static.File(staticdir))
         if re.search(r'^\d', webport):