[PATCHv2 2/2] Allow to create the root MailDir directory

[Sebastian Spaeth]

We currently do not allow nametrans rules such as
nametrans = lambda foldername: re.sub('^INBOX$', '', foldername)

because we crash with a traceback when running:
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=499755

The underlying reason is that we cannot create the "top level" root
directory of the Maildir in the function makefolders(), it will bail
out. John Goerzen intentionally prevented offlineimap from creating the
top-level dir, so that a misconfiguration could not arbitrarily create
folders on the file system. I believe that it should be perfectly
possible to automatically create the root dirctory of the maildir. We
still protect against folder creations at arbitrary places in the file
system though.

This patch cleans up makefolders(), adds documentation, allows to
automatically create rootfolders if needed (using absolute paths) and
adds some robustness in case the folders already exist that we want to
create (rather than simply crapping out).

Signed-off-by: Sebastian Spaeth <Sebastian at SSpaeth.de>
---
OK, this is v2, which split error reporting out. This patch does not change the current behavior but for 1 thing: Previously we used "relative" foldernames and trying to create a folder in the "root" of a MailDir crapped out with "mkdir('')". This version uses absolute folder names (preferrably anyway), and is thus capable of handling the MailDir root, so that "nametrans= lambda x: re.sub('^INBOX.', '',x)"

As we still don't allow "../" in the file path we can be sure that we only allow to create directories below the configured MailDir root, ie not in arbitrary places in the file system.

 offlineimap/repository/Maildir.py |   78 ++++++++++++++++++------------------
 1 files changed, 39 insertions(+), 39 deletions(-)

diff --git a/offlineimap/repository/Maildir.py b/offlineimap/repository/Maildir.py
index 18fa591..2a10a93 100644
--- a/offlineimap/repository/Maildir.py
+++ b/offlineimap/repository/Maildir.py
@@ -65,46 +65,46 @@ class MaildirRepository(BaseRepository):
         return self.getconf('sep', '.').strip()
 
     def makefolder(self, foldername):
-        self.debug("makefolder called with arg " + repr(foldername))
-        # Do the chdir thing so the call to makedirs does not make the
-        # self.root directory (we'd prefer to raise an error in that case),
-        # but will make the (relative) paths underneath it.  Need to use
-        # makedirs to support a / separator.
-        self.debug("Is dir? " + repr(os.path.isdir(foldername)))
+        """Create new Maildir folder if necessary
+
+        :param foldername: A relative mailbox name. The maildir will be
+            created in self.root+'/'+foldername. All intermediate folder
+            levels will be created if they do not exist yet. 'cur',
+            'tmp', and 'new' subfolders will be created in the maildir.
+        """
+        self.debug("makefolder called with arg '%s'" % (foldername))
+        full_path = os.path.abspath(os.path.join(self.root, foldername))
+    
+        # sanity tests
         if self.getsep() == '/':
-            for invalid in ['new', 'cur', 'tmp', 'offlineimap.uidvalidity']:
-                for component in foldername.split('/'):
-                    assert component != invalid, "When using nested folders (/ as a separator in the account config), your folder names may not contain 'new', 'cur', 'tmp', or 'offlineimap.uidvalidity'."
-
-        assert foldername.find('./') == -1, "Folder names may not contain ../"
+            for component in foldername.split('/'):
+                assert not component in ['new', 'cur', 'tmp'],\
+                    "When using nested folders (/ as a Maildir separator), "\
+                    "folder names may not contain 'new', 'cur', 'tmp'."
+        assert foldername.find('../') == -1, "Folder names may not contain ../"
         assert not foldername.startswith('/'), "Folder names may not begin with /"
 
-        oldcwd = os.getcwd()
-        os.chdir(self.root)
-
-        # If we're using hierarchical folders, it's possible that sub-folders
-        # may be created before higher-up ones.  If this is the case,
-        # makedirs will fail because the higher-up dir already exists.
-        # So, check to see if this is indeed the case.
-
-        if (self.getsep() == '/' or self.getconfboolean('existsok', 0) or foldername == '.') \
-            and os.path.isdir(foldername):
-            self.debug("makefolder: %s already is a directory" % foldername)
-            # Already exists.  Sanity-check that it's not a Maildir.
-            for subdir in ['cur', 'new', 'tmp']:
-                assert not os.path.isdir(os.path.join(foldername, subdir)), \
-                       "Tried to create folder %s but it already had dir %s" %\
-                       (foldername, subdir)
-        else:
-            self.debug("makefolder: calling makedirs %s" % foldername)
-            assert foldername != '', "Can not create root MailDir."
-            os.makedirs(foldername, 0700)
-        self.debug("makefolder: creating cur, new, tmp")
+        # If we're using hierarchical folders, it's possible that
+        # sub-folders may be created before higher-up ones.
+        self.debug("makefolder: calling makedirs '%s'" % full_path)
+        try:
+            os.makedirs(full_path, 0700)
+        except OSError, e:
+            if e.errno == 17 and os.path.isdir(full_path):
+                self.debug("makefolder: '%s' already a directory" % foldername)
+            else:
+                raise
         for subdir in ['cur', 'new', 'tmp']:
-            os.mkdir(os.path.join(foldername, subdir), 0700)
-        # Invalidate the cache
+            try:
+                os.mkdir(os.path.join(full_path, subdir), 0700)
+            except OSError, e:
+                if e.errno == 17 and os.path.isdir(full_path):
+                    self.debug("makefolder: '%s' already has subdir %s" %
+                               (foldername, sudir))
+                else:
+                    raise
+        # Invalidate the folder cache
         self.folders = None
-        os.chdir(oldcwd)
 
     def deletefolder(self, foldername):
         self.ui.warn("NOT YET IMPLEMENTED: DELETE FOLDER %s" % foldername)
@@ -132,11 +132,11 @@ class MaildirRepository(BaseRepository):
 
         self.debug("  toppath = %s" % toppath)
 
-        # Iterate over directories in top.
-        for dirname in os.listdir(toppath) + ['.']:
+        # Iterate over directories in top & top itself.
+        for dirname in os.listdir(toppath) + [toppath]:
             self.debug("  *** top of loop")
             self.debug("  dirname = %s" % dirname)
-            if dirname in ['cur', 'new', 'tmp', 'offlineimap.uidvalidity']:
+            if dirname in ['cur', 'new', 'tmp']:
                 self.debug("  skipping this dir (Maildir special)")
                 # Bypass special files.
                 continue
@@ -162,7 +162,7 @@ class MaildirRepository(BaseRepository):
                 retval.append(folder.Maildir.MaildirFolder(self.root, foldername,
                                                            self.getsep(), self, self.accountname,
                                                            self.config))
-            if self.getsep() == '/' and dirname != '.':
+            if self.getsep() == '/' and dirname:
                 # Check sub-directories for folders.
                 retval.extend(self._getfolders_scandir(root, foldername))
         self.debug("_GETFOLDERS_SCANDIR RETURNING %s" % \
-- 
1.7.4.1