[Quickfix-developers] Acceptor thread leaks and race condition cleanup patches

[Gene G. <mus...@ya...>]

1) Acceptor leaks thread in which onRun is running.
The code uses incorrect function (the one returning
boolean, not threadid) to spawn the onRun thread, and
uses resulting "1" instead of correct thread id to
join. The consequenses are that accptor->stop (called
after onRun) continues running after acceptor.start
returns and is acceptor instance gets deleted, which
often results in crashes in my server.
2) After fixing above, a race condition in
ThreadedSocketAcceptor is apparent. onStop thread
iterates over the collection of open connection
threads trying to join them. This loop is protected by
mutex. However the connection threads themselves
attempt to erase themself from the same collection,
and deadlock on the same mutex. The fix is to treat
shutdown as the special case and when a m_stop flag is
set, skip per-thread cleanup. 
m_stop has to be protected by a separate mutex. My
patch uses a class MtVar(.h) (tested internally on all
platforms) which allows to change only the
declaration: bool m_stop to MtVar<bool> m_stop and
have exact same semantics elsewhere, only in a
thread-safe way.
Four files are attached (in a zip): 
patches for Acceptor.cpp, ThreadedSocketAccpeptor.cpp
and .h and MtVar.h

Gene


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