X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Ftracepoint.c;h=b109fe30152b2968f7aba03736bab0cae53dbd89;hb=2df82195d140b39c40abfb43d526804a9d14d3da;hp=2c25d46250b603c6ed3e5c987f24aae905ef482a;hpb=2c05c691a10f3130f9339a15369140ad6ca70f85;p=lttng-ust.git

diff --git a/liblttng-ust/tracepoint.c b/liblttng-ust/tracepoint.c
index 2c25d462..b109fe30 100644
--- a/liblttng-ust/tracepoint.c
+++ b/liblttng-ust/tracepoint.c
@@ -26,7 +26,7 @@
 #include <stdio.h>
 
 #include <urcu/arch.h>
-#include <urcu-bp.h>
+#include <urcu/urcu-bp.h>
 #include <urcu/hlist.h>
 #include <urcu/uatomic.h>
 #include <urcu/compiler.h>
@@ -53,6 +53,22 @@ struct {
 /* Set to 1 to enable tracepoint debug output */
 static const int tracepoint_debug;
 static int initialized;
+
+/*
+ * If tracepoint_destructors_state = 1, tracepoint destructors are
+ * enabled. They are disabled otherwise.
+ */
+static int tracepoint_destructors_state = 1;
+
+/*
+ * Expose the now deprecated symbol __tracepoints__disable_destructors for
+ * backward compatibility of applications built against old versions of
+ * lttng-ust. We need to keep __tracepoints__disable_destructors up to date
+ * within the new destructor disabling API because old applications read this
+ * symbol directly.
+ */
+int __tracepoints__disable_destructors __attribute__((weak));
+
 static void (*new_tracepoint_cb)(struct lttng_ust_tracepoint *);
 
 /*
@@ -150,7 +166,7 @@ static void release_probes(void *old)
 	if (old) {
 		struct tp_probes *tp_probes = caa_container_of(old,
 			struct tp_probes, probes[0]);
-		synchronize_rcu();
+		urcu_bp_synchronize_rcu();
 		free(tp_probes);
 	}
 }
@@ -734,7 +750,7 @@ void __tracepoint_probe_prune_release_queue(void)
 	release_queue_need_update = 0;
 
 	/* Wait for grace period between all sync_callsites and free. */
-	synchronize_rcu();
+	urcu_bp_synchronize_rcu();
 
 	cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
 		cds_list_del(&pos->u.list);
@@ -825,7 +841,7 @@ void tracepoint_probe_update_all(void)
 
 	tracepoint_update_probes();
 	/* Wait for grace period between update_probes and free. */
-	synchronize_rcu();
+	urcu_bp_synchronize_rcu();
 	cds_list_for_each_entry_safe(pos, next, &release_probes, u.list) {
 		cds_list_del(&pos->u.list);
 		free(pos);
@@ -971,15 +987,40 @@ void exit_tracepoint(void)
 
 void tp_rcu_read_lock_bp(void)
 {
-	rcu_read_lock_bp();
+	urcu_bp_read_lock();
 }
 
 void tp_rcu_read_unlock_bp(void)
 {
-	rcu_read_unlock_bp();
+	urcu_bp_read_unlock();
 }
 
 void *tp_rcu_dereference_sym_bp(void *p)
 {
-	return rcu_dereference_bp(p);
+	return urcu_bp_dereference(p);
+}
+
+/*
+ * Programs that have threads that survive after they exit, and therefore call
+ * library destructors, should disable the tracepoint destructors by calling
+ * tp_disable_destructors(). This will leak the tracepoint
+ * instrumentation library shared object, leaving its teardown to the operating
+ * system process teardown.
+ *
+ * To access and/or modify this value, users need to use a combination of
+ * dlopen(3) and dlsym(3) to get an handle on the
+ * tp_disable_destructors and tp_get_destructors_state symbols below.
+ */
+void tp_disable_destructors(void)
+{
+	uatomic_set(&tracepoint_destructors_state, 0);
+}
+
+/*
+ * Returns 1 if the destructors are enabled and should be executed.
+ * Returns 0 if the destructors are disabled.
+ */
+int tp_get_destructors_state(void)
+{
+	return uatomic_read(&tracepoint_destructors_state);
 }