update(userspace/falco): initial CLI porting to cxxopts

Signed-off-by: Leonardo Di Donato <leodidonato@gmail.com>

userspace/falco/cli.cpp

@@ -0,0 +1,22 @@
+/*
+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 "cli.h"
+
+namespace falco
+{
+
+} // namespace falco

userspace/falco/cli.h

@@ -0,0 +1,188 @@
+/*
+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 <cxxopts.hpp>
+
+namespace falco
+{
+
+class option_requires_specific_argument_exception : public cxxopts::OptionParseException
+{
+public:
+	explicit option_requires_specific_argument_exception(const std::string& option, const std::string& values):
+		OptionParseException("Option " + cxxopts::LQUOTE + option + cxxopts::RQUOTE + " requires an argument equal to " + values)
+	{
+	}
+};
+
+class option_cannot_be_specified_exception : public cxxopts::OptionParseException
+{
+public:
+	explicit option_cannot_be_specified_exception(const std::string& option1, const std::string& option2):
+		OptionParseException("Options " + cxxopts::LQUOTE + option1 + cxxopts::RQUOTE + " and " + cxxopts::LQUOTE + option2 + cxxopts::RQUOTE + " can not be specified together")
+	{
+	}
+};
+
+class cli
+{
+public:
+	cli(int argc, const char** argv):
+		m_argc(argc), m_argv(argv), m_options("falco", "Cloud-Native Runtime Security")
+	{
+	}
+	virtual ~cli()
+	{
+	}
+
+	void run()
+	{
+		// These options give some info about Falco (Falco exits).
+		m_options.add_options(
+			"help",
+			{
+				{"h,help", "Print help page."},
+				{"support", "Print support information (version, rules files, etc.)."},
+				{"version", "Print version info."},
+			});
+
+		// These are options responsible for listing Falco elements (Falco exits).
+		m_options.add_options(
+			"list",
+			{
+				{"L", "Show name and description of all rules."},
+				{"l", "Show name and description of a specific rule.", cxxopts::value<std::string>(), "rule name"},
+				{"list", "Show all fields.", cxxopts::value<std::string>()->implicit_value("all"), "sycall|k8s_audit"},
+				{"N", "Show field names only."},
+			});
+
+		// m_options.add_options(
+		// 	"output",
+		// 	{
+		// 		{},
+		// 	});
+
+		// m_options.add_options(
+		// 	"input",
+		// 	{
+		// 		{},
+		// 	});
+
+		m_options.add_options(
+			"filtering",
+			{
+				{"D", "Disable any rules with names having the given substring. Can be specified multiple times. Can not be specified with -t.", cxxopts::value<std::vector<std::string>>(), "substring"},
+				{"T", "Disable any rules with a specific tag. Can be specified several times. Can not be specified with -t.", cxxopts::value<std::vector<std::string>>(), "tag"},
+				{"t", "Only run those rules with a specific tag. Can be specified several times. Can not be specified with -T or -D.", cxxopts::value<std::vector<std::string>>(), "tag"},
+			});
+
+		m_result = m_options.parse(m_argc, m_argv);
+
+		process();
+	}
+
+private:
+	void process()
+	{
+		if(m_result.count("help") && m_result["help"].as<bool>())
+		{
+			std::cout << m_options.help() << std::endl;
+			// todo: print > exit
+		}
+
+		if(m_result.count("support") && m_result["support"].as<bool>())
+		{
+			// todo: argv + config rule filenames > cmdline > print > exit
+		}
+
+		if(m_result.count("version") && m_result["version"].as<bool>())
+		{
+			// todo: print > exit
+		}
+
+		if(m_result.count("L") && m_result["L"].as<bool>())
+		{
+			// todo: engine > print > exit
+			// engine->describe_rule(NULL)
+		}
+
+		if(m_result.count("l"))
+		{
+			// todo: engine > print > exit
+			// engine->describe_rule(m_result["l"].as<string>());
+		}
+
+		if(m_result.count("list"))
+		{
+			auto source = m_result["list"].as<std::string>();
+			// todo: retrieve implicit value
+			if(source.empty() || (source != "syscall" && source != "k8s_audit" && source != "all"))
+			{
+				throw falco::option_requires_specific_argument_exception(
+					"list",
+					cxxopts::LQUOTE + "syscall" + cxxopts::RQUOTE + " or " + cxxopts::LQUOTE + "k8s_audit" + cxxopts::RQUOTE);
+			}
+
+			bool names_only = false;
+			if(m_result.count("N"))
+			{
+				names_only = m_result["N"].as<bool>();
+			}
+
+			// todo: engine + names_only + source
+			// se valore == syscall ==> + [-V]
+		}
+
+		bool count_D = m_result.count("D");
+		bool count_t = m_result.count("t");
+		bool count_T = m_result.count("T");
+		if(count_D > 0)
+		{
+			if(count_t > 0)
+			{
+				throw falco::option_cannot_be_specified_exception("D", "t");
+			}
+			// todo
+			// engine > not exit
+		}
+		if(count_T > 0)
+		{
+			if(count_t > 0)
+			{
+				throw falco::option_cannot_be_specified_exception("T", "t");
+			}
+			// todo
+			// engine > not exit
+		}
+		if(count_t > 0)
+		{
+			// todo
+			// engine > not exit
+		}
+	}
+
+	int m_argc;
+	const char** m_argv;
+	cxxopts::Options m_options;
+	cxxopts::ParseResult m_result;
+};
+
+} // namespace falco
+
+// 3 tipi di azioni
+// quelle che una volta date devono farlo uscire e non hanno bisogno di nessuna istanza
+// quelle che hanno bisogno di inspector e/o engine e poi falco esce
+// quelle che hanno bisogno di inspector e/o engine e poi falco esegue