[PATCH v3 4/8] kernel-shark: Add logic for the plugins search path

[Yordan Karadzhov <ykaradzhov@xxxxxxxxxx>]

If the application has been started from the source code directory, all
build-in plugins will be loaded from kernel-shark/lib/
If the application has been started from its installation location, all
build-in plugins will be loaded from INSTALL_PREFIX/lib/kshark/plugins/

Signed-off-by: Yordan Karadzhov <ykaradzhov@xxxxxxxxxx>
---
 kernel-shark/build/deff.h.cmake         |  3 +++
 kernel-shark/src/KsUtils.cpp            | 35 +++++++++++++++++--------
 kernel-shark/src/KsUtils.hpp            |  1 +
 kernel-shark/src/plugins/CMakeLists.txt |  2 +-
 4 files changed, 29 insertions(+), 12 deletions(-)

diff --git a/kernel-shark/build/deff.h.cmake b/kernel-shark/build/deff.h.cmake
index 8041cfc..ba211f4 100644
--- a/kernel-shark/build/deff.h.cmake
+++ b/kernel-shark/build/deff.h.cmake
@@ -14,6 +14,9 @@
 /** KernelShark source code path. */
 #cmakedefine KS_DIR "@KS_DIR@"
 
+/** KernelShark installation prefix path. */
+#cmakedefine _INSTALL_PREFIX "@_INSTALL_PREFIX@"
+
 /** Location of the trace-cmd executable. */
 #cmakedefine TRACECMD_BIN_DIR "@TRACECMD_BIN_DIR@"
 
diff --git a/kernel-shark/src/KsUtils.cpp b/kernel-shark/src/KsUtils.cpp
index 6af0c66..b05c0dc 100644
--- a/kernel-shark/src/KsUtils.cpp
+++ b/kernel-shark/src/KsUtils.cpp
@@ -423,13 +423,12 @@ 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;
 
@@ -458,13 +457,12 @@ 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;
 
@@ -487,6 +485,23 @@ void KsPluginManager::unregisterFromList(kshark_context *kshark_ctx)
 			lamUregUser);
 }
 
+char *KsPluginManager::_pluginLibFromName(const QString &plugin, int &n)
+{
+	QString path = QCoreApplication::applicationFilePath();
+	std::string pluginStr = plugin.toStdString();
+	char *lib;
+
+	if (path.contains(KS_DIR)) {
+		n = asprintf(&lib, "%s/lib/plugin-%s.so",
+			     KS_DIR, 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.
  *
@@ -508,8 +523,7 @@ 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;
@@ -570,8 +584,7 @@ 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;
@@ -579,7 +592,7 @@ 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 77048ab..019bde8 100644
--- a/kernel-shark/src/KsUtils.hpp
+++ b/kernel-shark/src/KsUtils.hpp
@@ -238,6 +238,7 @@ signals:
 
 private:
 	void _parsePluginList();
+	char *_pluginLibFromName(const QString &plugin, int &n);
 
 	template <class T>
 	void _forEachInList(const QStringList &pl,
diff --git a/kernel-shark/src/plugins/CMakeLists.txt b/kernel-shark/src/plugins/CMakeLists.txt
index 6098275..64cf98d 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)
-- 
2.20.1