I've been attempting to get to get Shared Folders and ACL's to work under dovecot 1.0rc17.  Unfortunately, I've run into some problems (many have already been mentioned on the list), specifically the problem where folder-specific ACL files are not found (and I will not use Global ACL's due to the 100% probability of cross-namespace mailbox name conflicts).  My namespace is as follows:

namespace private {

   separator = /

   prefix = 

   location = maildir:%h/Maildir

   inbox = yes

}

namespace private {

   separator = /

   prefix = CIW Archived/

   location = maildir:%h/Mailarchive

}

namespace public {

   separator = /

   prefix = CIW Groups/

   location = maildir:/srv/export/groups:CONTROL=%h/Maildir/public-subscriptions:INDEX=%h/Maildir/public-index

}

I decided to run a quick strace on dovecot's imap daemon while I was getting a folder listing to see why dovecot was not finding the folder-specific ACLs.  Below are what I feel are the two key instances in the trace:

Example 1: searching for ACL on private folder

open("/etc/dovecot-acls//.DEFAULT", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/home/ghuntress/Maildir/./dovecot-acl", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/etc/dovecot-acls/Work", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/home/ghuntress/Maildir/.Work/dovecot-acl", O_RDONLY) = -1 ENOENT (No such file or directory)

stat("/etc/dovecot-acls/", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0

open("/etc/dovecot-acls/", O_RDONLY)    = 7

That looks good.  The ACL plugin looking for the global acls first in the correct location, then in the maildir itself for the folder-specific acl.

Example 2: searching for ACL on shared folder

open("/etc/dovecot-acls//.DEFAULT", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/home/ghuntress/Maildir/public-subscriptions/./dovecot-acl", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/etc/dovecot-acls/IS.Postmaster", O_RDONLY) = -1 ENOENT (No such file or directory)

open("/home/ghuntress/Maildir/public-subscriptions/.IS.Postmaster/dovecot-acl", O_RDONLY) = -1 ENOENT (No such file or directory)

stat("/etc/dovecot-acls/", {st_mode=S_IFDIR|0755, st_size=4096, ...}) = 0

open("/etc/dovecot-acls/", O_RDONLY)    = 7

I'm not terribly familiar with the inner workings of Dovecot, however I can envision two possible fixes:

1.) Always have the ACL plugin look under the maildir location (and not the CONTROL override) for folder-specific ACLs

or

2.) Have dovecot always place subscriptions for shared folders in a user-specific directory regardless of the namespace location configuration (although, this would probably break a ton of production configurations).

I don't know what either of the above options would break, but I hope it's gives some ideas on how to fix this long-standing bug.

Please let me know if I can be of any more help.

-Garret