new(userspace/falco): program output C++ impl

Signed-off-by: Leonardo Grasso <me@leonardograsso.com>

userspace/falco/falco_outputs_program.cpp

@@ -0,0 +1,66 @@
+/*
+Copyright (C) 2020 The Falco Authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#include "falco_outputs_program.h"
+#include <stdio.h>
+#include "banned.h" // This raises a compilation error when certain functions are used
+
+void falco::outputs::output_program::open_pfile()
+{
+
+	if(m_pfile == nullptr)
+	{
+		m_pfile = popen(m_oc.options["program"].c_str(), "w");
+		// todo(leogr): handle errno
+	}
+
+	// if(!m_buffered)
+	// {
+	// 	m_pipe.rdbuf()->pubsetbuf(0, 0);
+	// }
+}
+
+void falco::outputs::output_program::output_event(gen_event *evt, std::string &rule, std::string &source,
+						  falco_common::priority_type priority, std::string &format, std::string &msg)
+{
+	output_msg(priority, msg);
+}
+
+void falco::outputs::output_program::output_msg(falco_common::priority_type priority, std::string &msg)
+{
+	open_pfile();
+	fprintf(m_pfile, "%s\n", msg.c_str());
+
+	if(m_oc.options["keep_alive"] != "true")
+	{
+		cleanup();
+	}
+}
+
+void falco::outputs::output_program::cleanup()
+{
+	if(m_pfile != nullptr)
+	{
+		fflush(m_pfile);
+		fclose(m_pfile);
+	}
+}
+
+void falco::outputs::output_program::reopen()
+{
+	cleanup();
+	open_pfile();
+}

userspace/falco/falco_outputs_program.h

@@ -0,0 +1,44 @@
+/*
+Copyright (C) 2020 The Falco Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+#pragma once
+
+#include "falco_output.h"
+
+namespace falco
+{
+namespace outputs
+{
+
+class output_program : public output
+{
+	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();
+
+	void reopen();
+
+private:
+	void open_pfile();
+
+	FILE *m_pfile;
+};
+
+} // namespace outputs
+} // namespace falco