[Dovecot] C programmers, please help. need dovecot patch

[Adam M. Dunn]

Thanks for the lead.  I'll take a look at this when I get a chance and try
to pin it down.



~Adam


On Tue, 4 Apr 2006, Jorgen Lundman wrote:

> 
> Thought I would peek at it while I was checking the busy-loop bug. My guess is 
> that imap/namespace.c, which does some checks, like:
> 
> 
>          /* first try NAMESPACE_* environments */
> [...]
>                  data = getenv(t_strdup_printf("NAMESPACE_%u", i));
> 
> [...]
> 
>          /* fallback to MAIL */
>          mail = getenv("MAIL");
>          if (mail == NULL) {
>                  /* support also maildir-specific environment */
>                  mail = getenv("MAILDIR");
> 
> [...]
> 
>          ns->storage = mail_storage_create_with_data(mail, user, flags,
>                                                      lock_method);
> 
> 
> 
> Now,
> 
> mail_storage_create_with_data(const char *data, const char *user,
>                                enum mail_storage_flags flags,
>                                enum mail_storage_lock_method lock_method)
> {
> 
> It checks if "data" is NULL/*0, if so call mail_storage_create_default(user, 
> flags, lock_method);
> - but that should not happen as the getenv() code checks for NULLs.
> 
> It checks to see if mbox: or maildir: prefix is set.
> 
> Otherwise, calls,
>                  storage = mail_storage_autodetect(data, flags);
> 
> if that fails it send the error:
>                  if (storage == NULL) {
>                          i_error("Ambiguous mail location setting, "
>                                  "don't know what to do with it: %s "
>                                  "(try prefixing it with mbox: or maildir:)",
>                                  data);
> 
> Presumably, you do not get that error as it is fatal?
> 
> Hence, in autodetect it calls each methods.autodetect function, for example for 
> mbox:
> 
>          if (*path != '\0' && mbox_is_file(path, "INBOX file", debug))
>                  return TRUE;
> 
>          if (mbox_is_dir(t_strconcat(path, "/.imap", NULL), "has .imap/", debug))
>                  return TRUE;
>          if (mbox_is_file(t_strconcat(path, "/inbox", NULL), "has inbox", debug))
>                  return TRUE;
>          if (mbox_is_file(t_strconcat(path, "/mbox", NULL), "has mbox", debug))
>                  return TRUE;
> 
>          return FALSE;
> 
> 
> 
> and for maildir:
> 
>          path = t_strconcat(data, "/cur", NULL);
>          if (stat(path, &st) < 0) {
> 		return FALSE;
> 	}
> 
>          return TRUE;
> 
> 
> 
> Which would imply that Maildir will only return FALSE for failures, but 
> otherwise default to TRUE. And mbox is the opposite, only returns TRUE if it 
> finds what it likes, otherwise FALSE. So the default appears to be Maildir.
> 
> But in your situation, it detects mbox first. Either due to MAIL envvar is set, 
> or, one of the 4 tests return TRUE.
> 
> But then, I've only spent 5 minutes on the code, so I don't really know. You'd 
> have to use gdb (or turn on debug output at the very least) to see which path it 
> takes.
> 
> What is interesting though is that it appears to iterate the storage classes in 
> order, which appears to be Maildir, mbox, dbox.  So, Maildir just fails, but 
> your mbox.autodetect does not fail (or you would get the above error).
> 
> 
> Lund
> 
> 
> Adam M. Dunn wrote:
> > Hi all.
> > 
> > Can any C programmers out there tell me how to fix Dovecot to default to
> > Maildir format when autodecting can't find anything?  I don't know C, but
> > it seems like it would be a simple thing.
> > 
> > 
> > Right now, I use the autodetect mailbox feature because we want users to
> > choose to optionally be able to use Mbox format (we have some diehard unix
> > users with non-maildir clients). I have Maildrop setup to check for the
> > existance of a ~/Maildir folder in the user's home, and if it exists, it
> > delivers there.  Otherwise it falls back to ~/Mail where mbox style files
> > go.
> > 
> > The problem with Dovecot is there is no way to tell the autodetect feature
> > what to default to, and if it can't find anything, it automatically
> > creates a folder called ~/mail under the user's home and primes it with
> > an Mbox file, but I'd rather it create a ~/Maildir instead.  So if we have
> > for example, a new user with no mail yet, and they log in via IMAP before
> > getting any mail from maildrop, Dovecot will create a them a ~/mail
> > folder.  So when they DO get mail, our maildrop filters will think they
> > are an Mbox user.  I could do some fancy Maildrop filters to fix that when
> > they get their first mail, but in the meantime the unknowing user could
> > try creating things via IMAP that gets overwritten.  Anyway, it would be
> > much cleaner if Dovecot just did what I wanted.
> > 
> > 
> > If anyone could point me to the place to patch my copy of Dovecot, I would
> > GREATLY apprecieate it.  I don't know C, but I know many other languages.
> > 
> > 
> > I would also like to see this be added via the config file in future
> > releases.  So consider this a feature request.  Not only that, but more
> > control over the autodetection process in general would be REALLY nice.
> > 
> > 
> > Thanks.
> > Adam
> > 
> > 
> > 
> 
> -- 
> Jorgen Lundman       | <lundman at lundman.net>
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> 
>