--- a/cwconfig.py	Thu Jul 08 08:54:45 2010 +0200
+++ b/cwconfig.py	Thu Jul 08 10:03:03 2010 +0200
@@ -991,6 +991,29 @@
         """write down current configuration"""
         self.generate_config(open(self.main_config_file(), 'w'))
 
+    def check_writeable_uid_directory(self, path):
+        """check given directory path exists, belongs to the user running the
+        server process and is writeable.
+
+        If not, try to fix this, leting exception propagate when not possible.
+        """
+        if not exists(path):
+            os.makedirs(path)
+        if self['uid']:
+            try:
+                uid = int(self['uid'])
+            except ValueError:
+                from pwd import getpwnam
+                uid = getpwnam(self['uid']).pw_uid
+        else:
+            uid = os.getuid()
+        fstat = os.stat(path)
+        if fstat.st_uid != uid:
+            os.chown(path, uid, os.getgid())
+        import stat
+        if not (fstat.st_mode & stat.S_IWUSR):
+            os.chmod(path, fstat.st_mode | stat.S_IWUSR)
+
     @cached
     def instance_md5_version(self):
         import hashlib

--- a/etwist/server.py	Thu Jul 08 08:54:45 2010 +0200
+++ b/etwist/server.py	Thu Jul 08 10:03:03 2010 +0200
@@ -402,6 +402,7 @@
 def run(config, vreg=None, debug=None):
     if debug is not None:
         config.debugmode = debug
+    config.check_writeable_uid_directory(config.appdatahome)
     # create the site
     root_resource = CubicWebRootResource(config, vreg=vreg)
     website = server.Site(root_resource)

--- a/server/serverconfig.py	Thu Jul 08 08:54:45 2010 +0200
+++ b/server/serverconfig.py	Thu Jul 08 10:03:03 2010 +0200
@@ -15,9 +15,8 @@
 #
 # You should have received a copy of the GNU Lesser General Public License along
 # with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
-"""server.serverconfig definition
+"""server.serverconfig definition"""
 
-"""
 __docformat__ = "restructuredtext en"
 
 from os.path import join, exists

--- a/web/webconfig.py	Thu Jul 08 08:54:45 2010 +0200
+++ b/web/webconfig.py	Thu Jul 08 10:03:03 2010 +0200
@@ -15,9 +15,8 @@
 #
 # You should have received a copy of the GNU Lesser General Public License along
 # with CubicWeb.  If not, see <http://www.gnu.org/licenses/>.
-"""common web configuration for twisted/modpython instances
+"""web ui configuration for cubicweb instances"""
 
-"""
 __docformat__ = "restructuredtext en"
 _ = unicode
 
@@ -335,8 +334,10 @@
     def _build_ui_properties(self):
         # self.datadir_url[:-1] to remove trailing /
         from cubicweb.web.propertysheet import PropertySheet
+        cachedir = join(self.appdatahome, 'uicache')
+        self.check_writeable_uid_directory(cachedir)
         self.uiprops = PropertySheet(
-            join(self.appdatahome, 'uicache'),
+            cachedir,
             data=lambda x: self.datadir_url + x,
             datadir_url=self.datadir_url[:-1])
         self._init_uiprops(self.uiprops)