kernel-shark: Add logic for the plugins search path

If the application has not been started from its installation location
and the directory

 app_file_path + "../../kernel-shark/lib"

exists, all build-in plugins will be loaded from this directory. In any
other case all build-in plugins will be loaded from

_INSTALL_PREFIX/lib/kshark/plugins/

Link: http://lore.kernel.org/linux-trace-devel/20190504130702.27755-1-ykaradzhov@vmware.com

Suggested-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reviewed-by: Slavomir Kaslev <kaslevs@vmware.com>
Signed-off-by: Yordan Karadzhov <ykaradzhov@vmware.com>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

3 files changed, 30 insertions, 12 deletions

diff --git a/kernel-shark/src/KsUtils.cpp b/kernel-shark/src/KsUtils.cpp
index 8c42206e..3e88d962 100644
--- a/kernel-shark/src/KsUtils.cpp
+++ b/kernel-shark/src/KsUtils.cpp
@@ -544,13 +544,12 @@ void KsPluginManager::_parsePluginList()
  */
 void KsPluginManager::registerFromList(kshark_context *kshark_ctx)
 {
-	auto lamRegBuiltIn = [&kshark_ctx](const QString &plugin)
+	auto lamRegBuiltIn = [&kshark_ctx, this](const QString &plugin)
 	{
 		char *lib;
 		int n;
 
-		n = asprintf(&lib, "%s/lib/plugin-%s.so",
-			     KS_DIR, plugin.toStdString().c_str());
+		lib = _pluginLibFromName(plugin, n);
 		if (n <= 0)
 			return;
 
@@ -579,13 +578,12 @@ void KsPluginManager::registerFromList(kshark_context *kshark_ctx)
  */
 void KsPluginManager::unregisterFromList(kshark_context *kshark_ctx)
 {
-	auto lamUregBuiltIn = [&kshark_ctx](const QString &plugin)
+	auto lamUregBuiltIn = [&kshark_ctx, this](const QString &plugin)
 	{
 		char *lib;
 		int n;
 
-		n = asprintf(&lib, "%s/lib/plugin-%s.so",
-			     KS_DIR, plugin.toStdString().c_str());
+		lib = _pluginLibFromName(plugin, n);
 		if (n <= 0)
 			return;
 
@@ -608,6 +606,26 @@ void KsPluginManager::unregisterFromList(kshark_context *kshark_ctx)
 			lamUregUser);
 }
 
+char *KsPluginManager::_pluginLibFromName(const QString &plugin, int &n)
+{
+	QString appPath = QCoreApplication::applicationDirPath();
+	QString libPath = appPath + "/../../kernel-shark/lib";
+	std::string pluginStr = plugin.toStdString();
+	char *lib;
+
+	libPath = QDir::cleanPath(libPath);
+	if (!KsUtils::isInstalled() && QDir(libPath).exists()) {
+		std::string pathStr = libPath.toStdString();
+		n = asprintf(&lib, "%s/plugin-%s.so",
+			     pathStr.c_str(), pluginStr.c_str());
+	} else {
+		n = asprintf(&lib, "%s/lib/kshark/plugins/plugin-%s.so",
+			     _INSTALL_PREFIX, pluginStr.c_str());
+	}
+
+	return lib;
+}
+
 /**
  * @brief Register a Plugin.
  *
@@ -629,8 +647,7 @@ void KsPluginManager::registerPlugin(const QString &plugin)
 			 * The argument is the name of the plugin. From the
 			 * name get the library .so file.
 			 */
-			n = asprintf(&lib, "%s/lib/plugin-%s.so",
-					KS_DIR, plugin.toStdString().c_str());
+			lib = _pluginLibFromName(plugin, n);
 			if (n > 0) {
 				kshark_register_plugin(kshark_ctx, lib);
 				_registeredKsPlugins[i] = true;
@@ -691,8 +708,7 @@ void KsPluginManager::unregisterPlugin(const QString &plugin)
 			 * The argument is the name of the plugin. From the
 			 * name get the library .so file.
 			 */
-			n = asprintf(&lib, "%s/lib/plugin-%s.so", KS_DIR,
-				     plugin.toStdString().c_str());
+			lib = _pluginLibFromName(plugin, n);
 			if (n > 0) {
 				kshark_unregister_plugin(kshark_ctx, lib);
 				_registeredKsPlugins[i] = false;
@@ -700,7 +716,7 @@ void KsPluginManager::unregisterPlugin(const QString &plugin)
 			}
 
 			return;
-		} else if  (plugin.contains("/lib/plugin-" +
+		} else if (plugin.contains("/lib/plugin-" +
 			                   _ksPluginList[i], Qt::CaseInsensitive)) {
 			/*
 			 * The argument is the name of the library .so file.
diff --git a/kernel-shark/src/KsUtils.hpp b/kernel-shark/src/KsUtils.hpp
index 7b80b21c..1c872711 100644
--- a/kernel-shark/src/KsUtils.hpp
+++ b/kernel-shark/src/KsUtils.hpp
@@ -241,6 +241,8 @@ signals:
 private:
 	void _parsePluginList();
 
+	char *_pluginLibFromName(const QString &plugin, int &n);
+
 	template <class T>
 	void _forEachInList(const QStringList &pl,
 			    const QVector<bool> &reg,
diff --git a/kernel-shark/src/plugins/CMakeLists.txt b/kernel-shark/src/plugins/CMakeLists.txt
index 60982757..64cf98d1 100644
--- a/kernel-shark/src/plugins/CMakeLists.txt
+++ b/kernel-shark/src/plugins/CMakeLists.txt
@@ -29,6 +29,6 @@ BUILD_PLUGIN(NAME missed_events
 list(APPEND PLUGIN_LIST "missed_events default") # This plugin will be loaded by default
 
 install(TARGETS sched_events missed_events
-        LIBRARY DESTINATION ${_INSTALL_PREFIX}/lib/kshark/)
+        LIBRARY DESTINATION ${_INSTALL_PREFIX}/lib/kshark/plugins/)
 
 set(PLUGINS ${PLUGIN_LIST} PARENT_SCOPE)