From: Michal Sojka <sojkam1@fel.cvut.cz>
Date: Sun, 20 Feb 2011 09:42:58 +0000 (+0100)
Subject: forb: Fix synchronization error in forbrun
X-Git-Url: http://rtime.felk.cvut.cz/gitweb/frescor/frsh-forb.git/commitdiff_plain/63aeaf83152befc7bb438b04b9921f1988d0011b

forb: Fix synchronization error in forbrun

forbrun starts servers synchronously, i.e. the next server is started
only after the previous one is fully initialized (see
forb_signal_server_ready()). This synchronization was broken because
forb_signal_server_ready() was incorrectly called in
forb_execute_object() called from forb_execution_thread() called from
forb_init(). This caused that the semaphore for the synchronization had
the value of one (instead of zero) when forb_init() finished.
Therefore, the first waiting for the semaphore returned immediately
without actually waiting for the server.

This is now fixed by introduction of default_executor which is declared
in struct forb. This executor is initialized "manually", without
forb_execute_object(), so that the forb_signal_server_ready() is not
called.

In future, we might want use the default executor for executing requests
to other objects, which do not require a separate thread.
---

diff --git a/src/forb/src/forb-internal.h b/src/forb/src/forb-internal.h
index a513d93b..2bd141dc 100644
--- a/src/forb/src/forb-internal.h
+++ b/src/forb/src/forb-internal.h
@@ -113,7 +113,8 @@ typedef struct forb {
 	fosa_mutex_t regref_mutex;
 	gavl_cust_root_field_t regrefs;	/**< Container for ::forb_regref_t */
 
-	fosa_thread_id_t execution_thread; /**< Thread which executes remote requests for this forb::orb interface. */
+	fosa_thread_id_t execution_thread; /**< Thread which runs @a default_executor. */
+	forb_executor_t default_executor; /**< Executor that executes remote requests for this forb::orb interface. */
 } forb_t;
 
 typedef void (*forb_skel_func)(FORB_CDR_Codec *cin,
diff --git a/src/forb/src/forb.c b/src/forb/src/forb.c
index 63e51eb7..79759dad 100644
--- a/src/forb/src/forb.c
+++ b/src/forb/src/forb.c
@@ -150,9 +150,8 @@ forb_init_tmp_dir(void)
 static void *
 forb_execution_thread(void *arg)
 {
-	forb_orb orb = arg;
-
-	forb_execute_object(orb);
+	forb_executor_t *executor = arg;
+	forb_executor_run(executor);
 	return NULL;
 }
 
@@ -236,10 +235,15 @@ forb_init(int *argc, char **argv[], const struct forb_init_attr *attr)
 	 * can accept remote request to our new ORB. */
 	forb_objects_nolock_insert(forb, orb);
 
+	ret = forb_executor_init(&forb->default_executor);
+	if (ret) goto err2;
+	ret = forb_executor_register_object(&forb->default_executor, orb);
+	if (ret) goto err3;
+
 	ret = fosa_thread_create(&forb->execution_thread, NULL,
-				 forb_execution_thread, orb);
+				 forb_execution_thread, &forb->default_executor);
 	if (ret != 0)
-		goto err2;
+		goto err3;
 
 	/* FIXME: I do not know how to deregister the exit handler if
 	 * forb_destroy() is called manually. */
@@ -258,7 +262,7 @@ forb_init(int *argc, char **argv[], const struct forb_init_attr *attr)
 		}
 	err_free_unix:
 		free(port);
-		goto err2;
+		goto err3;
 	unix_ok:;
 	}
 #endif
@@ -279,13 +283,14 @@ forb_init(int *argc, char **argv[], const struct forb_init_attr *attr)
 		}
 	err_free_inet:
 		free(port);
-		goto err2;
+		goto err3;
 	inet_ok:;
 		hack_register_fcb(orb, port);
 	}
 #endif
 	return orb;
 
+err3:   forb_executor_destroy(&forb->default_executor);
 err2:	forb_free(forb);
 err:	return NULL;
 }
diff --git a/src/forb/src/forbrun/forbrun.c b/src/forb/src/forbrun/forbrun.c
index 9219cee4..426f773a 100644
--- a/src/forb/src/forbrun/forbrun.c
+++ b/src/forb/src/forbrun/forbrun.c
@@ -59,7 +59,7 @@ int main(int argc, char *argv[])
 	forb_orb orb;
 	bool opt_daemon = false;
 	char *opt_pidfile = NULL;
-	int i;
+	int i, ret;
 	forb_init_attr_t attr = {
 		.orb_id = "",
 		.peer_discovery_callback = NULL, /* TODO */
@@ -80,7 +80,6 @@ int main(int argc, char *argv[])
 					exit(0);
 				}
 				{
-					int ret;
 					ret = ul_log_domain_arg2levels(optarg);
 					if (ret) 
 						error(1, EINVAL, "Error parsing -l argument at char %d\n", ret);
@@ -142,7 +141,9 @@ int main(int argc, char *argv[])
 		fosa_thread_create(&tid, NULL, forb_main_thread, data);
 		libs_loaded_cnt++;
 
-		forb_wait_for_server_ready(orb);
+		ret = forb_wait_for_server_ready(orb);
+		if (ret)
+			error(1, errno, "forb_wait_for_server_ready");
 	}
 
 	if (opt_daemon)
diff --git a/src/forb/src/forbrun/tests/forbrun_printargs.c b/src/forb/src/forbrun/tests/forbrun_printargs.c
index 86aa4eb7..a28f0e75 100644
--- a/src/forb/src/forbrun/tests/forbrun_printargs.c
+++ b/src/forb/src/forbrun/tests/forbrun_printargs.c
@@ -1,15 +1,18 @@
 #include <forb.h>
 #include <stdio.h>
+#include <error.h>
 
 int forb_main(forb_orb orb, int argc, char *argv[])
 {
-	int i;
+	int i, ret;
 	for (i=0; i<argc; i++)
 		printf("%s%s", argv[i], i+1 < argc ? " " : "");
 	printf("\n");
 	if (argc < 2 || strcmp(argv[1], "--exit") != 0) {
 		/* Allow starting the next shared library */
-		forb_signal_server_ready(orb);
+		ret = forb_signal_server_ready(orb);
+		if (ret)
+			error(1, errno, "forb_signal_server_ready");
 		/* Exit only this thread, not the whole forbrun */
 		pthread_exit(0);
 	}