This fix also fixes the deadlock issue without putting any
new strain into the main packet processing path.
Instead of occasionally returning true in MaybeReady sometime,
we occasionally process threads if time_mgr time is not running.
If time_mgr time is running, we have heartbeat messages that will
trigger processing in any case -- processing always checks the
exact state of the Queues.
This fix probably also means that we can remove the communication
loads from all input framework tests and run them all simultaneously.
Bernhard and I tracked it down we believe: the thread queue could
deadlock in certain cases. As a fix we tuned the heuristic for telling
if a queue might have input to occasionaly err on the safe side by
flagging "yes", so that processing will proceed.
It's a bit unfortunate to apply this fix last minute before the
release as it could potentially impact performance if the heuristic
fails to often. We believe the chosen parmaterization should be fine ...
statistics, finalize prepared statement before exitting logger.
This might fix the deadlock issue, at least it did not happen for
me on my tried on the test system where it happened quite regularly
before.
* origin/topic/bernhard/thread-cleanup:
and just to be really sure - always make threads go through OnWaitForStop
hopefully finally fix last interesting race-condition
it is apparently getting a bit late for changes at important code...
spoke to soon (forgot to comment in line again).
Change thread shutdown again to also work with input framework.
Changing semantics of thread stop methods.
Support for cleaning up threads that have terminated.
Now it should work. However - this commit changes a basic assumption
of the threading queue. This basic assumption is, that nothing can
be read out of the out-queue of a dead thread. I think that reading
out of the queue of a dead thread makes perfect sense (when the thread
shuts down, pushes the rest of its work on the queue and says bye,
and wants the main thread to pick it up afterwards) - however, I
guess one can be of a differing opinion here.
In any case, it makes stuff a bit easier to understand - in my opinion.
It took me a while to find out why the messages disappear in thin
air and never arrive in the main thread ;)
* topic/robin/master-test: (60 commits)
Script fix for Linux.
Updating test base line.
Another small change to MsgThread API.
Bug fix for BasicThread.
make version_ok return true for TLSv12
Sed usage in canonifier script didn't work on non-Linux systems.
Changing HTTP DPD port 3138 to 3128.
Temporarily removing tuning/logs-to-elasticsearch.bro from the test-all-policy.
More documentation updates.
Revert "Fixing calc_next_rotate to use UTC based time functions."
Some documentation updates for elasticsearch plugin.
Give configure a --disable-perftools option.
Updating tests for the #start/#end change.
Further threading and API restructuring for logging and input frameworks.
Reworking forceful thread termination.
Moving the ASCII writer over to use UNIX I/O rather than stdio.
Further reworking the thread API.
Reworking thread termination logic.
If a thread doesn't terminate, we log that but not longer proceed (because it could hang later still).
Removing the thread kill functionality.
...
frameworks.
There were a number of cases that weren't thread-safe. In particular,
we don't use std::string anymore for anything that's passed between
threads (but instead plain old const char*, with manual memmory
managmenet).
This is still a check-point commit, I'll do more testing.
This is based on Gilbert's code but I ended up refactoring it quite a
bit. That's why I didn't do a direct merge but started with a new
branch and copied things over to adapt. It looks quite a bit different
now as I tried to generalize things a bit more to also support the
Input Framework.
The larger changes code are:
- Moved all logging code into subdirectory src/logging/. Code
here is in namespace "logging".
- Moved all threading code into subdirectory src/threading/. Code
here is in namespace "threading".
- Introduced a central thread manager that tracks threads and is
in charge of termination and (eventually) statistics.
- Refactored logging independent threading code into base classes
BasicThread and MsgThread. The former encapsulates all the
pthread code with simple start/stop methods and provides a
single Run() method to override.
The latter is derived from BasicThread and adds bi-directional
message passing between main and child threads. The hope is that
the Input Framework can reuse this part quite directly.
- A log writer is now split into a general WriterFrontend
(LogEmissary in Gilbert's code) and a type-specific
WriterBackend. Specific writers are implemented by deriving from
the latter. (The plugin interface is almost unchanged compared
to the 2.0 version.).
Frontend and backend communicate via MsgThread's message
passing.
- MsgThread (and thus WriterBackend) has a Heartbeat() method that
a thread can override to execute code on a regular basis. It's
triggered roughly once a second by the main thread.
- Integration into "the rest of Bro". Threads can send messages to
the reporter and do debugging output; they are hooked into the
I/O loop for sending messages back; and there's a new debugging
stream "threading" that logs, well, threading activity.
This all seems to work for the most part, but it's not done yet.
TODO list:
- Not all tests pass yet. In particular, diffs for the external
tests seem to indicate some memory problem (no crashes, just an
occasional weird character).
- Only tested in --enable-debug mode.
- Only tested on Linux.
- Needs leak check.
- Each log write is currently a single inter-thread message. Bring
Gilbert's bulk writes back.
- Code needs further cleanup.
- Document the class API.
- Document the internal structure of the logging framework.
- Check for robustness: live traffic, aborting, signals, etc.
- Add thread statistics to profile.log (most of the code is there).
- Customize the OS-visible thread names on platforms that support it.
