From 1e2f2d7da0ee22e35670856ad964671848e186b4 Mon Sep 17 00:00:00 2001 From: moneromooo-monero Date: Tue, 22 Dec 2015 12:31:22 +0000 Subject: [PATCH] epee: fix hang on exit When the boost ioservice is stopped, pending work notifications will not happen. This includes deadline timers, which would otherwise time out the now cancelled I/O operations. When this happens just after starting a new connect operation, this can leave that operations in a state where it won't receive either the completion notification nor a timeout, causing a hang. This is fixed by keeping a list of connections corresponding to the connect operations, and cancelling them before stopping the boost ioservice. Note that the list of these connections can grow unbounded, as they're never cleaned up. Cleaning them up would involve working out which connections do not have any pending work, and it's not quite clear yet how to go about this. --- .../epee/include/net/abstract_tcp_server2.h | 5 +++++ .../epee/include/net/abstract_tcp_server2.inl | 21 ++++++++++++++++++- 2 files changed, 25 insertions(+), 1 deletion(-) diff --git a/contrib/epee/include/net/abstract_tcp_server2.h b/contrib/epee/include/net/abstract_tcp_server2.h index 8043c0876..77396ade4 100644 --- a/contrib/epee/include/net/abstract_tcp_server2.h +++ b/contrib/epee/include/net/abstract_tcp_server2.h @@ -110,6 +110,8 @@ namespace net_utils bool speed_limit_is_enabled() const; ///< tells us should we be sleeping here (e.g. do not sleep on RPC connections) + + bool cancel(); private: //----------------- i_service_endpoint --------------------- @@ -303,6 +305,9 @@ namespace net_utils /// The next connection to be accepted connection_ptr new_connection_; + std::mutex connections_mutex; + std::deque connections_; + }; // class <>boosted_tcp_server diff --git a/contrib/epee/include/net/abstract_tcp_server2.inl b/contrib/epee/include/net/abstract_tcp_server2.inl index b75a9ecaa..cb8bdc6ee 100644 --- a/contrib/epee/include/net/abstract_tcp_server2.inl +++ b/contrib/epee/include/net/abstract_tcp_server2.inl @@ -565,7 +565,12 @@ PRAGMA_WARNING_DISABLE_VS(4355) return true; CATCH_ENTRY_L0("connection::close", false); } - + //--------------------------------------------------------------------------------- + template + bool connection::cancel() + { + return close(); + } //--------------------------------------------------------------------------------- template void connection::handle_write(const boost::system::error_code& e, size_t cb) @@ -871,6 +876,12 @@ POP_WARNINGS } m_stop_signal_sent = true; TRY_ENTRY(); + connections_mutex.lock(); + for (auto &c: connections_) + { + c->cancel(); + } + connections_mutex.unlock(); io_service_.stop(); CATCH_ENTRY_L0("boosted_tcp_server::send_stop_signal()", void()); } @@ -914,6 +925,10 @@ POP_WARNINGS TRY_ENTRY(); connection_ptr new_connection_l(new connection(io_service_, m_config, m_sock_count, m_sock_number, m_pfilter, m_connection_type) ); + connections_mutex.lock(); + connections_.push_back(new_connection_l); + LOG_PRINT_L2("connections_ size now " << connections_.size()); + connections_mutex.unlock(); boost::asio::ip::tcp::socket& sock_ = new_connection_l->socket(); ////////////////////////////////////////////////////////////////////////// @@ -1006,6 +1021,10 @@ POP_WARNINGS { TRY_ENTRY(); connection_ptr new_connection_l(new connection(io_service_, m_config, m_sock_count, m_sock_number, m_pfilter, m_connection_type) ); + connections_mutex.lock(); + connections_.push_back(new_connection_l); + LOG_PRINT_L2("connections_ size now " << connections_.size()); + connections_mutex.unlock(); boost::asio::ip::tcp::socket& sock_ = new_connection_l->socket(); //////////////////////////////////////////////////////////////////////////