Felix Walter 72d3806066 aap2_agent: Switch to simple_queue to enforce clean termination ... This enables a clean termination of all agent connections on program exit without memory leaks that might previously occur due to the "pipe queue" still holding some data (pointer to allocated memory) when close() is called on the pipe. For that purpose, the "pipe queue" is replaced by our standard hal_queue implementation, which also has a higher performance as it does not require a syscall on every read/write operation. As hal_queue does not support poll() (it does not provide a fd), we cannot check whether the socket has been closed by a subscribing AAP2 client while concurrently waiting for the internal queue. As an alternative, this implements a liveliness check, which checks the sub. connection opportunistically from the agent manager: When a new registration is requested, existing registrations are first "health-checked" and removed if down, so the new connection can take over if an old one is down and this was not detected previously. Based on the new infrastructure, a clean termination routine is implemented that terminates all tasks transitively by terminating the listener. An AAP2 connection handler ("comm task") can terminate in two ways: 1. During runtime, when the connection is closed, it must clean up its own resources. 2. On program termination, all connections must be cleanly closed and all outstanding mesages handled. For 1., we keep using detached threads and allow them to release all the resources. This commit mainly introduces a mechanism for 2.: A list tracking all comm. tasks is added that can be used to terminate and wait for all of them on program termination. A "termination flag" indicates whether tasks should clean up by themselves or the listener task takes it over. Everything needs to be protected by mutexes for safe concurrency. There is specific handling for macOS, which does not signal other threads clocking on a socket that the socket has been closed when calling shutdown() but only when calling close() - thus, close() is executed earlier on macOS. Also, macOS does not unblock poll() when the socket is close()d, so we do not use it anymore to wait for data on an RPC connection, but rather set SO_RCVTIMEO for active-client (RPC) connections to enforce the keepalive timeout. Signed-off-by: Felix Walter <felix.walter@d3tn.com>		2024-06-21 10:36:30 +02:00
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aap2_agent.h	aap2_agent: Switch to simple_queue to enforce clean termination	2024-06-21 10:36:30 +02:00