Bug #33721056 - C/C++ classic driver does not detect the plugin directory based on driver path

Author: Bogdan Degtyariov

driver/mysql_connection.cpp

@@ -576,6 +576,7 @@ void MySQL_Connection::init(ConnectOptionsMap & properties)
   */
 
   {
+    sql::SQLString plugin_dir;
     it = properties.find(OPT_PLUGIN_DIR);
 
     if (it != properties.end()) {
@@ -584,12 +585,28 @@ void MySQL_Connection::init(ConnectOptionsMap & properties)
       } catch (sql::InvalidArgumentException&) {
         throw sql::InvalidArgumentException("Wrong type passed for pluginDir expected sql::SQLString");
       }
-      if (p_s) {
-        proxy->options(sql::mysql::MYSQL_PLUGIN_DIR, *p_s);
-      }
-      else {
-        throw sql::InvalidArgumentException("No string value passed for pluginDir");
-      }
+    }
+#if(_WIN32 && CONCPP_BUILD_SHARED)
+    else {
+      /*
+        Note: For DLL in Windows we will try to set the plugin directory
+        based on driver_dll_path.
+      */
+      plugin_dir = driver_dll_path;
+#ifdef _DEBUG
+      // Debug dll is placed inside debug subdirectory
+      plugin_dir.append("..\\");
+#endif
+      plugin_dir.append("plugin");
+      p_s = &plugin_dir;
+    }
+#endif
+
+    if (p_s) {
+      proxy->options(sql::mysql::MYSQL_PLUGIN_DIR, *p_s);
+    } else if (it != properties.end()) {
+      // Throw only when OPT_PLUGIN_DIR is used, but no value is given
+      throw sql::InvalidArgumentException("No string value passed for pluginDir");
     }
   }
 

driver/mysql_connection.h

@@ -36,6 +36,10 @@
 #include "cppconn/connection.h"
 #include <memory>
 
+#if(_WIN32 && CONCPP_BUILD_SHARED)
+extern std::string driver_dll_path;
+#endif
+
 namespace sql
 {
 namespace mysql

driver/mysql_driver.cpp

@@ -29,6 +29,9 @@
  */
 
 
+#ifdef _WIN32
+#include <Windows.h>
+#endif
 
 #include "mysql_connection.h"
 #include "version_info.h"
@@ -187,6 +190,27 @@ void MySQL_Driver::setCallBack(sql::Fido_Callback& cb)
 
 } /* namespace sql */
 
+#if(_WIN32 && CONCPP_BUILD_SHARED)
+std::string driver_dll_path;
+
+BOOL WINAPI DllMain(
+  _In_ HINSTANCE hmodule,
+  _In_ DWORD,
+  _In_ LPVOID
+)
+{
+  /*
+    For Windows DLL we will store the current module path to allow detecting
+    directories with the plugins and dependencies.
+  */
+  char _driver_dll_path[1024] = { 0 };
+  GetModuleFileNameA(hmodule, _driver_dll_path, sizeof(_driver_dll_path));
+  driver_dll_path = _driver_dll_path;
+  driver_dll_path = driver_dll_path.substr(0, driver_dll_path.find_last_of('\\') + 1);
+  return true;
+}
+#endif
+
 /*
  * Local variables:
  * tab-width: 4