An interesting shutdown race in messaging

[Andrew Bartlett]

G'Day,

I have another messaging issue that has come up.

In my attempts to make progress on the ldb locking code, I tried moving
all of the servers in 'make test' to the standard process model. 

However, this hits an issue in the auth_log tests, which use messaging
to contact an external python process, the tests, which expect to be
sent the audit messages.

The issue is that in -M standard and in smbd, the connection can be
closed so fast that the messages that are written to the logs, and have
presumably been dispached to a messaging thread, never make it to the
other end.

I can work around it by holding the connection open in some of the
tests, but I can't easily do that for the tests that call rpcclient
over subprocess, or where the password fails on LDAP.

So, I wonder if there is a way to, before we call exit(0) in the
standard process model, have it try again to dispatch the messages to
somewhere safely on the other side of a connected or datagram fd?

This can be seen in the auth_log tests in 
http://git.catalyst.net.nz/gitweb?p=samba.git;a=shortlog;h=refs/heads/ldb-safe-locking-for-master

The commit that causes the issue is 
http://git.catalyst.net.nz/gitweb?p=samba.git;a=commitdiff;h=6cf5e9f9b9f27af56a5a42ea6d7259f06f35240c

(changing all "single" to "standard" in Samba4.pm).

Fixing this would allow folks to use the messaging transport for the
auth audit messages in a reliable way (instead of reading the logs),
which isn't currently promised (only listed as a developer feature
right now), but could be quite handy.  

Any clues most appreciated,

(Jeremy CC'ed because I mentioned this to him a long while ago).

Thanks,

Andrew Bartlett

-- 
Andrew Bartlett
https://samba.org/~abartlet/
Authentication Developer, Samba Team         https://samba.org
Samba Development and Support, Catalyst IT   
https://catalyst.net.nz/services/samba