use signalfd to stop on SIGTERM

Is this an overkill? I don't know.

The thing is, correctly intercepting SIGTERM (also SIGINT, etc.) is
incredibly tricky. For example, before this commit, my I/O loops in
server.c and worker.c were inherently racy.

This was immediately obvious if you tried to run the tests. The tests
(especially the Valgrind flavour) would run a worker, wait until it
prints a "Waiting for a new command" line, and try to kill it using
SIGTERM. The problem is, the global_stop_flag check could have already
been executed by the worker, and it would hang forever in recv().

The solution seems to be to use signalfd and select()/poll(). I've never
used either before, but it seems to work well enough - at least the very
same tests pass and don't hang now.

1 files changed, 2 insertions, 2 deletions

diff --git a/src/worker_main.c b/src/worker_main.c
index b9e9b9b..dcfee47 100644
--- a/src/worker_main.c
+++ b/src/worker_main.c
@@ -70,11 +70,11 @@ int main(int argc, char *argv[])
 	if (ret < 0)
 		return ret;
 
-	ret = worker_create(&worker);
+	ret = worker_create(&worker, &settings);
 	if (ret < 0)
 		return ret;
 
-	ret = worker_main(worker, &settings);
+	ret = worker_main(worker);
 	if (ret < 0)
 		goto destroy_worker;