X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=lttng-clock.c;fp=lttng-clock.c;h=4296d6c133f24e65040069e0c6e019c16a751537;hb=2754583e7a52bb07e00d9c20f8f6790adb1bc503;hp=0000000000000000000000000000000000000000;hpb=9616f0bf9524fc6b8ad184e87f4935c97f78a8bc;p=lttng-modules.git

diff --git a/lttng-clock.c b/lttng-clock.c
new file mode 100644
index 00000000..4296d6c1
--- /dev/null
+++ b/lttng-clock.c
@@ -0,0 +1,110 @@
+/*
+ * lttng-clock.c
+ *
+ * Copyright (C) 2014 Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; only
+ * version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <linux/module.h>
+#include <linux/kmod.h>
+#include <linux/mutex.h>
+
+#include "wrapper/trace-clock.h"
+#include "lttng-events.h"
+#include "lttng-tracer.h"
+
+struct lttng_trace_clock *lttng_trace_clock;
+EXPORT_SYMBOL_GPL(lttng_trace_clock);
+
+static DEFINE_MUTEX(clock_mutex);
+static struct module *lttng_trace_clock_mod;	/* plugin */
+static int clock_used;				/* refcount */
+
+int lttng_clock_register_plugin(struct lttng_trace_clock *ltc,
+		struct module *mod)
+{
+	int ret = 0;
+
+	mutex_lock(&clock_mutex);
+	if (clock_used) {
+		ret = -EBUSY;
+		goto end;
+	}
+	if (lttng_trace_clock_mod) {
+		ret = -EEXIST;
+		goto end;
+	}
+	/* set clock */
+	ACCESS_ONCE(lttng_trace_clock) = ltc;
+	lttng_trace_clock_mod = mod;
+end:
+	mutex_unlock(&clock_mutex);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(lttng_clock_register_plugin);
+
+void lttng_clock_unregister_plugin(struct lttng_trace_clock *ltc,
+		struct module *mod)
+{
+	mutex_lock(&clock_mutex);
+	WARN_ON_ONCE(clock_used);
+	if (!lttng_trace_clock_mod) {
+		goto end;
+	}
+	WARN_ON_ONCE(lttng_trace_clock_mod != mod);
+
+	ACCESS_ONCE(lttng_trace_clock) = NULL;
+	lttng_trace_clock_mod = NULL;
+end:
+	mutex_unlock(&clock_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_clock_unregister_plugin);
+
+void lttng_clock_ref(void)
+{
+	mutex_lock(&clock_mutex);
+	clock_used++;
+	if (lttng_trace_clock_mod) {
+		int ret;
+
+		ret = try_module_get(lttng_trace_clock_mod);
+		if (!ret) {
+			printk(KERN_ERR "LTTng-clock cannot get clock plugin module\n");
+			ACCESS_ONCE(lttng_trace_clock) = NULL;
+			lttng_trace_clock_mod = NULL;
+		}
+	}
+	mutex_unlock(&clock_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_clock_ref);
+
+void lttng_clock_unref(void)
+{
+	mutex_lock(&clock_mutex);
+	clock_used--;
+	if (lttng_trace_clock_mod)
+		module_put(lttng_trace_clock_mod);
+	mutex_unlock(&clock_mutex);
+}
+EXPORT_SYMBOL_GPL(lttng_clock_unref);
+
+MODULE_LICENSE("GPL and additional rights");
+MODULE_AUTHOR("Mathieu Desnoyers <mathieu.desnoyers@efficios.com>");
+MODULE_DESCRIPTION("LTTng Clock");
+MODULE_VERSION(__stringify(LTTNG_MODULES_MAJOR_VERSION) "."
+	__stringify(LTTNG_MODULES_MINOR_VERSION) "."
+	__stringify(LTTNG_MODULES_PATCHLEVEL_VERSION)
+	LTTNG_MODULES_EXTRAVERSION);