diff --git a/src/mibew/install/dbperform.php b/src/mibew/install/dbperform.php
index 044caaff..5dfe54f1 100644
--- a/src/mibew/install/dbperform.php
+++ b/src/mibew/install/dbperform.php
@@ -15,6 +15,11 @@
  * limitations under the License.
  */
 
+/**
+ * Indicate that installation in progress
+ */
+define('INSTALLATION_IN_PROGRESS', TRUE);
+
 session_start();
 
 require_once(dirname(dirname(__FILE__)).'/libs/config.php');
diff --git a/src/mibew/install/index.php b/src/mibew/install/index.php
index 1933d333..b2317695 100644
--- a/src/mibew/install/index.php
+++ b/src/mibew/install/index.php
@@ -15,6 +15,11 @@
  * limitations under the License.
  */
 
+/**
+ * Indicate that installation in progress
+ */
+define('INSTALLATION_IN_PROGRESS', TRUE);
+
 session_start();
 
 require_once(dirname(dirname(__FILE__)).'/libs/config.php');
diff --git a/src/mibew/libs/common/misc.php b/src/mibew/libs/common/misc.php
index e6bcada9..b944f033 100644
--- a/src/mibew/libs/common/misc.php
+++ b/src/mibew/libs/common/misc.php
@@ -105,4 +105,17 @@ function array_flatten_recursive($arr) {
 	return $result;
 }
 
+/**
+ * Checks if currently processed script is installation script.
+ *
+ * @return boolean
+ */
+function installation_in_progress() {
+	if (!defined('INSTALLATION_IN_PROGRESS')) {
+		return FALSE;
+	}
+
+	return INSTALLATION_IN_PROGRESS;
+}
+
 ?>
\ No newline at end of file