[Dovecot] antispam plugin problem with dspam

[Harlan Stenn]

I got it working.

Here are the problems I fixed, and it would have been *lots* easier if
the dovecot antispam plugin had better error/debug logging.

Johannes, I can work on a patch for the following if you prefer, and I'd
much rather spend my time getting ntp-4.2.6 out the door.

Getting this working would have been lots easier if the dovecot-antispam
package would:

- build dspam-exec's argv before the fork so it can be fully and cleanly
  reported in the debug log
- If there is a problem, report WIFEXITED(status) and
  WEXITSTATUS(status)
- if the execv fails, log an error message, noting dspam_binary,
  strerror(errno) and the uid/gid

If you want to be thorough about it I recommend logging an error
whenever any system call fails.

The current freebsd ports tools offer postfix, dovecot,
dovecot-antispam, and dspam in a way that they do not play nicely
together.

The antispam plugin cannot exec the dspam binary.  Choices include
figuring out what user/group are needed (dspam is suid root, executable
by the root or the mail group only, and dovecot will exec it as
virtual/virtual), or opening up the execute privs on the dspam
executable.

The dspam.conf file will need a "Trust virtual" line in it.

There might have been something else.

Having said all this, I really appreciate the dovecot antispam plugin.

H