worker: allow graceful shutdowns

Well, maybe "graceful" is a strong word, but now you _can_ do

    ./server &
    ./worker &
    ./client ci_run URL REV && kill "$( pidof worker )"

and the worker will wait for the CI run to complete.

5 files changed, 81 insertions, 3 deletions

diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index c2333a8..6476318 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -29,7 +29,8 @@ add_executable(worker worker_main.c worker.c
     git.c
     msg.c
     net.c
-    process.c)
+    process.c
+    signal.c)
 
 target_link_libraries(server PRIVATE pthread)
 target_link_libraries(worker PRIVATE git2 pthread)
diff --git a/src/signal.c b/src/signal.c
new file mode 100644
index 0000000..fc4ac8b
--- /dev/null
+++ b/src/signal.c
@@ -0,0 +1,23 @@
+#include "signal.h"
+#include "log.h"
+
+#include <pthread.h>
+#include <signal.h>
+
+volatile sig_atomic_t global_stop_flag = 0;
+
+int signal_set_thread_attr(pthread_attr_t *attr)
+{
+	sigset_t set;
+	sigemptyset(&set);
+	sigaddset(&set, SIGINT);
+	sigaddset(&set, SIGQUIT);
+	sigaddset(&set, SIGTERM);
+
+	if (pthread_attr_setsigmask_np(attr, &set)) {
+		print_errno("pthread_attr_setsigmask_np");
+		return -1;
+	}
+
+	return 0;
+}
diff --git a/src/signal.h b/src/signal.h
new file mode 100644
index 0000000..ac6da9d
--- /dev/null
+++ b/src/signal.h
@@ -0,0 +1,28 @@
+#ifndef __SIGNAL_H__
+#define __SIGNAL_H__
+
+#include <pthread.h>
+#include <signal.h>
+#include <string.h>
+
+extern volatile sig_atomic_t global_stop_flag;
+
+static void signal_handler(int)
+{
+	global_stop_flag = 1;
+}
+
+static __attribute__((constructor)) void signal_handler_install()
+{
+	struct sigaction sa;
+	memset(&sa, 0, sizeof(sa));
+	sa.sa_handler = signal_handler;
+
+	sigaction(SIGINT, &sa, NULL);
+	sigaction(SIGQUIT, &sa, NULL);
+	sigaction(SIGTERM, &sa, NULL);
+}
+
+int signal_set_thread_attr(pthread_attr_t *attr);
+
+#endif
diff --git a/src/worker.c b/src/worker.c
index 0dc64d3..d26408f 100644
--- a/src/worker.c
+++ b/src/worker.c
@@ -5,6 +5,7 @@
 #include "msg.h"
 #include "net.h"
 #include "process.h"
+#include "signal.h"
 
 #include <errno.h>
 #include <pthread.h>
@@ -45,6 +46,13 @@ git_shutdown:
 
 void worker_destroy(struct worker *worker)
 {
+	print_log("Shutting down\n");
+
+	if (worker->task_active) {
+		if (pthread_join(worker->task, NULL))
+			print_errno("pthread_join");
+		worker->task_active = 0;
+	}
 	if (pthread_mutex_destroy(&worker->task_mtx))
 		print_errno("pthread_mutex_destroy");
 	close(worker->fd);
@@ -141,6 +149,7 @@ static void *worker_task_wrapper(void *_ctx)
 static int worker_schedule_task(struct worker *worker, const struct msg *msg, worker_task_body body)
 {
 	struct worker_task_context *ctx;
+	pthread_attr_t attr;
 	int ret = 0;
 
 	ctx = malloc(sizeof(*ctx));
@@ -156,15 +165,29 @@ static int worker_schedule_task(struct worker *worker, const struct msg *msg, wo
 		goto free_ctx;
 	}
 
+	ret = pthread_attr_init(&attr);
+	if (ret < 0) {
+		print_errno("pthread_attr_init");
+		goto free_msg;
+	}
+
+	ret = signal_set_thread_attr(&attr);
+	if (ret < 0)
+		goto free_attr;
+
 	ret = pthread_create(&worker->task, NULL, worker_task_wrapper, ctx);
 	if (ret < 0) {
 		print_errno("pthread_create");
-		goto free_msg;
+		goto free_attr;
 	}
 	worker->task_active = 1;
+	pthread_attr_destroy(&attr);
 
 	return ret;
 
+free_attr:
+	pthread_attr_destroy(&attr);
+
 free_msg:
 	msg_free(ctx->msg);
 	free(ctx->msg);
@@ -245,11 +268,13 @@ int worker_main(struct worker *worker, int, char *[])
 	if (ret < 0)
 		return ret;
 
-	while (1) {
+	while (!global_stop_flag) {
 		print_log("Waiting for a new command\n");
 
 		ret = msg_recv_and_handle(worker->fd, worker_msg_handler_lock, worker);
 		if (ret < 0)
 			return ret;
 	}
+
+	return ret;
 }
diff --git a/src/worker_main.c b/src/worker_main.c
index d88071d..b5ccd51 100644
--- a/src/worker_main.c
+++ b/src/worker_main.c
@@ -1,4 +1,5 @@
 #include "const.h"
+#include "signal.h"
 #include "worker.h"
 
 #include <getopt.h>