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fixed a race condition issue in TcpServer::stop()

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hyung-hwan 2018-10-28 15:49:46 +00:00
parent b57af4a2ef
commit 21e289aca7
2 changed files with 9 additions and 2 deletions
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2
qse/lib/si/App.cpp
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@ -344,7 +344,7 @@ int App::unset_signal_handler_no_mutex(int sig, int ignore)
if (sl._state == App::SIGNAL_ACCEPTED) if (sl._state == App::SIGNAL_ACCEPTED)
{ {
// the actual signal handler is called with the mutex locked. // the actual signal handler is called with the mutex locked.
// it must not call acceptSingal()/discardSignal()neglectSingal() // it must not call acceptSingal()/discardSignal()/neglectSingal()
// from within the handler. // from within the handler.
if (app->_guarded_child_pid >= 0) app->on_guard_signal (sig); if (app->_guarded_child_pid >= 0) app->on_guard_signal (sig);
app->on_signal (sig); app->on_signal (sig);

9
qse/lib/si/TcpServer.cpp
View File

@ -436,13 +436,20 @@ int TcpServer::stop () QSE_CPP_NOEXCEPT
{ {
if (this->server_serving) if (this->server_serving)
{ {
// set stop request before writing "Q" to avoid race condition.
// after qse_mux_poll() detects activity for "Q" written,
// it loops over to another qse_mux_poll(). the stop request
// test is done in between. if this looping is faster than
// setting stop request after "Q" writing, the second qse_mux_poll()
// doesn't see it set to true yet.
this->setStopRequested (true);
this->listener_list.mux_pipe_spl.lock (); this->listener_list.mux_pipe_spl.lock ();
if (this->listener_list.mux_pipe[1] >= 0) if (this->listener_list.mux_pipe[1] >= 0)
{ {
::write (this->listener_list.mux_pipe[1], "Q", 1); ::write (this->listener_list.mux_pipe[1], "Q", 1);
} }
this->listener_list.mux_pipe_spl.unlock (); this->listener_list.mux_pipe_spl.unlock ();
this->setStopRequested (true);
} }
return 0; return 0;
} }