Investigate the need for separate `pop` and `smtp` fields and rename them

[rimas-kudelis]

The current names of pop and smtp fields are not very descriptive, with pop usually containing the path to users homedir, and smtp usually containing path to their Maildir. It seems unclear why this data duplication is necessary when a) we could use CONCAT and b) we could probably not even use the Maildir subdirectory, instead putting virtual users' emails right to their homedir.

However, it seems that at least for piped users, the smtp field contains the pipe command to run. The way it has to be entered is quite unintuitive (the admin just has to know what to enter) and buggy due to not escaping quote characters on output.

I propose we rename the pop field to something else (e.g. home) and either drop the smtp field along with the procmail feature entirely, or refactor and rename it to only be used when procmail (or some other custom shell command) is involved. I don't like the idea of letting virtual email users run arbitrary commands on the server, and I'm not sure if we could just let them upload their procmailrc via php and then tell procmail to use that file. Having never used it or anything else, I'm not even sure if procmail is still a thing. Furthermore, managing filtering rules via an IMAP-like interface (read: Sieve) seems more attractive to me, and this approach is already supported by some clients, such as Roundcube (via the bundled Managesieve plugin) or Thunderbird (also via plugins, although it seems both of these are currently outdated).

[Udera]

I currently use the pipe command, to pass mails directly to dovecot. Dovecot integrates sieve-filters that you can manage via (managesieveplugin in Roundcube). It's really nice. Perhaps #150 is a better way to integrate dovecot.
However, a single user should not be able to modify the pipe commands.

I'm not sure if the initial purpose of some implementations was thought for real users on the system?

[runout-at]

Hi & sorry for lots of comments in the last days.
This is one more of the things i was thinking on creating a new WebUI and i agree on above comments.

• who should can define a pipe command? only postmasters or define a role for users who are allowed to?
• should go pipe commands in a separate/new DB field? i don't like mixing paths and commands in th same DB field.
• do we really need the Maildir path per user? I think a base path for the domain would do it - in case just add localpart/Maildir and we are good.

the exim config where smtp field is used:

# grep -A10 mysql -r conf.d/* |grep smtp |grep -v 'host\_smtp'
conf.d/router/250_vexim_virtual_domains:  data = ${lookup mysql{select smtp from users,domains \
conf.d/router/250_vexim_virtual_domains:  data = ${lookup mysql{select smtp from users,domains \
conf.d/router/250_vexim_virtual_domains-        select concat_ws('@', localpart, domains.domain), smtp, localpart, users.sa_tag*10 AS sa_tag, users.on_spamassassin AND domains.spamassassin AS on_spamassassin, \
conf.d/router/250_vexim_virtual_domains:  data = ${lookup mysql{select smtp from users,domains where localpart = '*' \
conf.d/router/249_vexim_ditch_routers:    data = ${lookup mysql{select concat(smtp,'/.Junk') \