General-purpose list_fields(), via factories

Take advantage of the changes in
https://github.com/falcosecurity/libs/pull/75 to have a
general-purpose way to list fields for a given event source.

in the engine, list_fields() now takes a source, iterates over filter
factories, and calls get_fields() for each factory, printing the results.

list_source_fields now calls the engine regardless of source.

Signed-off-by: Mark Stemm <mark.stemm@gmail.com>

userspace/engine/falco_engine.cpp

@@ -85,31 +85,46 @@ uint32_t falco_engine::engine_version()
 
 #define CONSOLE_LINE_LEN 79
 
-void falco_engine::list_fields(bool names_only)
+void falco_engine::list_fields(std::string &source, bool names_only)
 {
-	for(auto &chk_field : json_factory().get_fields())
+	for(auto &it : m_filter_factories)
+	{
+		if(source != "" && source != it.first)
+		{
+			continue;
+		}
+
+		for(auto &chk_field : it.second->get_fields())
 		{
 			if(!names_only)
 			{
-			printf("\n----------------------\n");
-			printf("Field Class: %s (%s)\n\n", chk_field.m_name.c_str(), chk_field.m_desc.c_str());
-			if(chk_field.m_class_info != "")
+				// Add some pretty printing around deesc, but if there's no desc keep
+				// as an empty string.
+				std::string desc = chk_field.desc;
+				if(!desc.empty())
 				{
-				std::string str = falco::utils::wrap_text(chk_field.m_class_info, 0, 0, CONSOLE_LINE_LEN);
+					desc = string(" (") + desc + ")";
+				}
+
+				printf("\n----------------------\n");
+				printf("Field Class: %s%s\n\n", chk_field.name.c_str(), desc.c_str());
+				if(chk_field.class_info != "")
+				{
+					std::string str = falco::utils::wrap_text(chk_field.class_info, 0, 0, CONSOLE_LINE_LEN);
 					printf("%s\n", str.c_str());
 				}
 			}
 
-		for(auto &field : chk_field.m_fields)
+			for(auto &field : chk_field.fields)
 			{
-			printf("%s", field.m_name.c_str());
+				printf("%s", field.name.c_str());
 
 				if(names_only)
 				{
 					printf("\n");
 					continue;
 				}
-			uint32_t namelen = field.m_name.size();
+				uint32_t namelen = field.name.size();
 
 				if(namelen >= DESCRIPTION_TEXT_START)
 				{
@@ -122,27 +137,12 @@ void falco_engine::list_fields(bool names_only)
 					printf(" ");
 				}
 
-			std::string desc = field.m_desc;
-			switch(field.m_idx_mode)
-			{
-			case json_event_filter_check::IDX_REQUIRED:
-			case json_event_filter_check::IDX_ALLOWED:
-				desc += " (";
-				desc += json_event_filter_check::s_index_mode_strs[field.m_idx_mode];
-				desc += ", ";
-				desc += json_event_filter_check::s_index_type_strs[field.m_idx_type];
-				desc += ")";
-				break;
-			case json_event_filter_check::IDX_NONE:
-			default:
-				break;
-			};
-
-			std::string str = falco::utils::wrap_text(desc, namelen, DESCRIPTION_TEXT_START, CONSOLE_LINE_LEN);
+				std::string str = falco::utils::wrap_text(field.desc, namelen, DESCRIPTION_TEXT_START, CONSOLE_LINE_LEN);
 				printf("%s\n", str.c_str());
 			}
 		}
 	}
+}
 
 void falco_engine::load_rules(const string &rules_content, bool verbose, bool all_events)
 {

userspace/engine/falco_engine.h

@@ -57,7 +57,8 @@ public:
 	static uint32_t engine_version();
 
 	// Print to stdout (using printf) a description of each field supported by this engine.
-	void list_fields(bool names_only=false);
+	// If source is non-empty, only fields for the provided source are printed.
+	void list_fields(std::string &source, bool names_only);
 
 	//
 	// Load rules either directly or from a filename.

userspace/engine/json_evt.cpp

@@ -690,7 +690,7 @@ size_t json_event_filter_check::parsed_size()
 	}
 }
 
-json_event_filter_check::check_info &json_event_filter_check::get_fields()
+json_event_filter_check::check_info &json_event_filter_check::get_info()
 {
 	return m_info;
 }
@@ -1432,7 +1432,7 @@ json_event_filter_factory::json_event_filter_factory()
 
 	for(auto &chk : m_defined_checks)
 	{
-		m_info.push_back(chk->get_fields());
+		m_info.push_back(chk->get_info());
 	}
 }
 
@@ -1464,9 +1464,51 @@ gen_event_filter_check *json_event_filter_factory::new_filtercheck(const char *f
 	return NULL;
 }
 
-std::list<json_event_filter_check::check_info> &json_event_filter_factory::get_fields()
+std::list<gen_event_filter_factory::filter_fieldclass_info> json_event_filter_factory::get_fields()
 {
-	return m_info;
+	std::list<gen_event_filter_factory::filter_fieldclass_info> ret;
+
+	// It's not quite copy to the public information, as m_info
+	// has addl info about indexing. That info is added to the
+	// description.
+
+	for(auto &chk: m_defined_checks)
+	{
+		json_event_filter_check::check_info &info = chk->get_info();
+		gen_event_filter_factory::filter_fieldclass_info cinfo;
+
+		cinfo.name = info.m_name;
+		cinfo.desc = info.m_desc;
+		cinfo.class_info = info.m_class_info;
+
+		for(auto &field : info.m_fields)
+		{
+			gen_event_filter_factory::filter_field_info info;
+			info.name = field.m_name;
+			info.desc = field.m_desc;
+
+			switch(field.m_idx_mode)
+			{
+			case json_event_filter_check::IDX_REQUIRED:
+			case json_event_filter_check::IDX_ALLOWED:
+				info.desc += " (";
+				info.desc += json_event_filter_check::s_index_mode_strs[field.m_idx_mode];
+				info.desc += ", ";
+				info.desc += json_event_filter_check::s_index_type_strs[field.m_idx_type];
+				info.desc += ")";
+				break;
+			case json_event_filter_check::IDX_NONE:
+			default:
+				break;
+			};
+
+			cinfo.fields.emplace_back(std::move(info));
+		}
+
+		ret.emplace_back(std::move(cinfo));
+	}
+
+	return ret;
 }
 
 json_event_formatter::json_event_formatter(json_event_filter_factory &json_factory, std::string &format):

userspace/engine/json_evt.h

@@ -189,7 +189,7 @@ public:
 	// brackets (e.g. ka.image[foo])
 	size_t parsed_size();
 
-	check_info &get_fields();
+	check_info &get_info();
 
 	//
 	// Allocate a new check of the same type. Must be overridden.
@@ -399,7 +399,7 @@ public:
 	gen_event_filter_check *new_filtercheck(const char *fldname);
 
 	// All defined field names
-	std::list<json_event_filter_check::check_info> &get_fields();
+	std::list<gen_event_filter_factory::filter_fieldclass_info> get_fields();
 
 private:
 	std::list<std::shared_ptr<json_event_filter_check>> m_defined_checks;

userspace/falco/falco.cpp

@@ -424,21 +424,14 @@ static void print_all_ignored_events(sinsp *inspector)
 	printf("\n");
 }
 
-static void list_source_fields(falco_engine *engine, bool verbose, bool names_only, std::string &source)
+static void list_source_fields(falco_engine *engine, bool names_only, std::string &source)
 {
 	if(source.size() > 0 &&
 	   !(source == "syscall" || source == "k8s_audit"))
 	{
 		throw std::invalid_argument("Value for --list must be \"syscall\" or \"k8s_audit\"");
 	}
-	if(source == "" || source == "syscall")
-	{
-		list_fields(verbose, false, names_only);
-	}
-	if(source == "" || source == "k8s_audit")
-	{
-		engine->list_fields(names_only);
-	}
+	engine->list_fields(source, names_only);
 }
 
 //
@@ -781,7 +774,7 @@ int falco_init(int argc, char **argv)
 
 		if(list_flds)
 		{
-			list_source_fields(engine, verbose, names_only, list_flds_source);
+			list_source_fields(engine, names_only, list_flds_source);
 			return EXIT_SUCCESS;
 		}