From: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Date: Tue, 14 Apr 2015 22:13:19 +0000 (-0400)
Subject: Fix: getcpu/clock plugin handle leak
X-Git-Tag: v2.7.0-rc1~42
X-Git-Url: https://git.lttng.org./?a=commitdiff_plain;h=4bc1ccd721114691c6f0dbd65335b3c43c9f895f;p=lttng-ust.git

Fix: getcpu/clock plugin handle leak

Keep the handle to the shared object in a static variable. Use it to
check whether it has already been initialized.

We don't allow dlclose() for now though, so it technically leaks, but at
least we keep a reference to the handle.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
---

diff --git a/liblttng-ust/lttng-clock.c b/liblttng-ust/lttng-clock.c
index e8391e6d..4299bcde 100644
--- a/liblttng-ust/lttng-clock.c
+++ b/liblttng-ust/lttng-clock.c
@@ -33,6 +33,9 @@ struct lttng_trace_clock *lttng_trace_clock;
 static
 struct lttng_trace_clock user_tc;
 
+static
+void *clock_handle;
+
 int lttng_ust_trace_clock_set_read64_cb(uint64_t (*read64)(void))
 {
 	if (CMM_LOAD_SHARED(lttng_trace_clock))
@@ -94,21 +97,21 @@ int lttng_ust_enable_trace_clock_override(void)
 void lttng_ust_clock_init(void)
 {
 	const char *libname;
-	void *handle;
 	void (*libinit)(void);
 
-
+	if (clock_handle)
+		return;
 	libname = lttng_secure_getenv("LTTNG_UST_CLOCK_PLUGIN");
 	if (!libname)
 		return;
-	handle = dlopen(libname, RTLD_NOW);
-	if (!handle) {
+	clock_handle = dlopen(libname, RTLD_NOW);
+	if (!clock_handle) {
 		PERROR("Cannot load LTTng UST clock override library %s",
 			libname);
 		return;
 	}
 	dlerror();
-	libinit = (void (*)(void)) dlsym(handle,
+	libinit = (void (*)(void)) dlsym(clock_handle,
 		"lttng_ust_clock_plugin_init");
 	if (!libinit) {
 		PERROR("Cannot find LTTng UST clock override library %s initialization function lttng_ust_clock_plugin_init()",
diff --git a/liblttng-ust/lttng-getcpu.c b/liblttng-ust/lttng-getcpu.c
index 3e675a5a..751affac 100644
--- a/liblttng-ust/lttng-getcpu.c
+++ b/liblttng-ust/lttng-getcpu.c
@@ -30,6 +30,9 @@
 
 int (*lttng_get_cpu)(void);
 
+static
+void *getcpu_handle;
+
 int lttng_ust_getcpu_override(int (*getcpu)(void))
 {
 	CMM_STORE_SHARED(lttng_get_cpu, getcpu);
@@ -39,20 +42,21 @@ int lttng_ust_getcpu_override(int (*getcpu)(void))
 void lttng_ust_getcpu_init(void)
 {
 	const char *libname;
-	void *handle;
 	void (*libinit)(void);
 
+	if (getcpu_handle)
+		return;
 	libname = lttng_secure_getenv("LTTNG_UST_GETCPU_PLUGIN");
 	if (!libname)
 		return;
-	handle = dlopen(libname, RTLD_NOW);
-	if (!handle) {
+	getcpu_handle = dlopen(libname, RTLD_NOW);
+	if (!getcpu_handle) {
 		PERROR("Cannot load LTTng UST getcpu override library %s",
 			libname);
 		return;
 	}
 	dlerror();
-	libinit = (void (*)(void)) dlsym(handle,
+	libinit = (void (*)(void)) dlsym(getcpu_handle,
 		"lttng_ust_getcpu_plugin_init");
 	if (!libinit) {
 		PERROR("Cannot find LTTng UST getcpu override library %s initialization function lttng_ust_getcpu_plugin_init()",