update(userspace/falco): improve stdout buffering

Signed-off-by: Leonardo Grasso <[email protected]>

userspace/falco/outputs_stdout.cpp

@@ -18,6 +18,20 @@ limitations under the License.
 #include <iostream>
 #include "banned.h" // This raises a compilation error when certain functions are used
 
+void falco::outputs::output_stdout::init_stdout()
+{
+	//
+	// By default, the standard output stream is fully buffered
+	// or line buffered if the stream can be determined to refer to
+	// an interactive device (e.g. in a TTY).
+	// Just enable automatic flushing when unbuffered output is desired.
+	//
+	if(!m_buffered)
+	{
+		std::cout << std::nounitbuf;
+	}
+}
+
 void falco::outputs::output_stdout::output_event(gen_event *evt, std::string &rule, std::string &source,
 						 falco_common::priority_type priority, std::string &format, std::string &msg)
 {
@@ -27,10 +41,6 @@ void falco::outputs::output_stdout::output_event(gen_event *evt, std::string &ru
 void falco::outputs::output_stdout::output_msg(falco_common::priority_type priority, std::string &msg)
 {
 	std::cout << msg + "\n";
-	if(!m_buffered)
-	{
-		std::cout.flush();
-	}
 }
 
 void falco::outputs::output_stdout::cleanup()

userspace/falco/outputs_stdout.h

@@ -25,12 +25,23 @@ namespace outputs
 
 class output_stdout : public abstract_output
 {
+
+	void init(config oc, bool buffered,
+		  bool time_format_iso_8601, std::string hostname)
+	{
+		abstract_output::init(oc, buffered, time_format_iso_8601, hostname);
+		init_stdout();
+	}
+
 	void output_event(gen_event *evt, std::string &rule, std::string &source,
 			  falco_common::priority_type priority, std::string &format, std::string &msg);
 
 	void output_msg(falco_common::priority_type priority, std::string &msg);
 
 	void cleanup();
+
+private:
+	void init_stdout();
 };
 
 } // namespace outputs