From ac1bf45ebdd630fbc9ad2c1fa3c0ea99f5206799 Mon Sep 17 00:00:00 2001
From: Simon Rettberg
Date: Wed, 28 Aug 2019 13:07:13 +0200
Subject: [SERVER] Make signal handling more POSIX

According to POSIX, a signal sent to a PID can be delivered to an
arbitrary thread of that process that hasn't the signal blocked. This
seens to never happen on Linux, but would mess things up since the code
expected the main signal handler to only be executed by the main thread.
This should now be fixed by examining the destination PID of the signal
as well as the ID of the thread currently running the signal handler. If
we notice the signal wasn't sent by our own PID and the handler is not
currently run by the main thread, we re-send the signal to the main
thread. Otherwise, if the signal was sent by our own PID but the handler
is not run in the main thread, do nothing. This way we can use
pthread_kill() to wake up threads that might be stuck in a blocking
syscall when it's time to shut down.
---
 src/server/threadpool.h | 5 +++++
 1 file changed, 5 insertions(+)

(limited to 'src/server/threadpool.h')

diff --git a/src/server/threadpool.h b/src/server/threadpool.h
index 15dd151..ee0b3aa 100644
--- a/src/server/threadpool.h
+++ b/src/server/threadpool.h
@@ -17,6 +17,11 @@ bool threadpool_init(int maxIdleThreadCount);
  */
 void threadpool_close();
 
+/**
+ * Block until all threads spawned have exited
+ */
+void threadpool_waitEmpty();
+
 /**
  * Run a thread using the thread pool.
  * @param startRoutine function to run in new thread
-- 
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