This patch makes the queue and couriers distinguish between permanent and
transient errors when delivering mail to individual recipients.
Pipe delivery errors are always permanent.
Procmail delivery errors are almost always permanent, except if the command
exited with code 75, which is an indication of transient.
SMTP delivery errors are almost always transient, except if the DNS resolution
for the domain failed.
This patch removes chasquid-userdb and adds a more generic and extensive
chasquid-util, that supports various operations on user databases as well as
aliases lookups.
The code is not very pretty but for now I took a more practical approach, the
tool is ancillary and can be tidied up later.
In some cases, it's be useful to have references to directories relative
to the configuration itself.
So this patch makes chasquid do a Chdir into it, so we can assume it in
the rest of the code and config.
This patch adds checks that verify:
- The envelope from must match the authenticated user. This prevents
impersonation at the envelope level (while still allowing bounces, of
course).
- If the destination is remote, then the user must have completed
authentication. This prevents unauthorized relaying.
The patch ends up adjusting quite a few tests, as they were not written
considering these restrictions so they have to be changed accordingly.
This patch introduces a new directory, test/, which contains a simple local
end-to-end test which runs a chasquid binary and uses msmtp to send an email,
which is delivered locally.
As it's the first one, it adds a bunch of common infrastructure to simplify
writing these kinds of tests.
More end-to-end tests will follow, and it's expected that the common
infrastructure will also change significantly to accomodate their needs.
