From 9899680064189ac0316ecd0fefe5db01b66fb23f Mon Sep 17 00:00:00 2001
From: Henri DF <henridf@gmail.com>
Date: Fri, 19 Feb 2016 20:24:33 -0800
Subject: [PATCH] Lua parser refactoring

Move compiler loading out of libsinsp/lua_parser.cpp and into a new
class in digwatch/rules.cpp.

This way the libsinsp support is strictly about providing a lua API for
scripts to setup filters. Loading the actual parser and rules is logic
that belongs in the app (digwatch in this case, maybe sysdig down the
line) rather than there.
---
 CMakeLists.txt                    |  3 +++
 userspace/digwatch/CMakeLists.txt |  3 ++-
 userspace/digwatch/digwatch.cpp   |  9 +++----
 userspace/digwatch/rules.cpp      | 45 +++++++++++++++++++++++++++++++
 userspace/digwatch/rules.h        | 17 ++++++++++++
 5 files changed, 71 insertions(+), 6 deletions(-)
 create mode 100644 userspace/digwatch/rules.cpp
 create mode 100644 userspace/digwatch/rules.h

diff --git a/CMakeLists.txt b/CMakeLists.txt
index a4366af0..292b7518 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -33,6 +33,9 @@ add_subdirectory(${SYSDIG_DIR} ${PROJECT_BINARY_DIR}/sysdig)
 set(CURL_BUNDLE_DIR "${sysdig_BINARY_DIR}/curl-prefix/src/curl")
 set(CURL_INCLUDE_DIR "${CURL_BUNDLE_DIR}/include/")
 set(CURL_LIBRARIES "${CURL_BUNDLE_DIR}/lib/.libs/libcurl.a")
+
+set(LUAJIT_INCLUDE_DIR "${sysdig_BINARY_DIR}/luajit-prefix/src/luajit/src")
+
 if(NOT USE_BUNDLED_OPENSSL)
 	set(CURL_SSL_OPTION "")
 else()
diff --git a/userspace/digwatch/CMakeLists.txt b/userspace/digwatch/CMakeLists.txt
index a539a445..aecf149d 100644
--- a/userspace/digwatch/CMakeLists.txt
+++ b/userspace/digwatch/CMakeLists.txt
@@ -1,4 +1,5 @@
 include_directories(${PROJECT_SOURCE_DIR}/../sysdig/userspace/libsinsp/third-party/jsoncpp)
+include_directories("${LUAJIT_INCLUDE_DIR}")
 
 if(NOT APPLE)
     include_directories("${CURL_INCLUDE_DIR}")
@@ -8,7 +9,7 @@ endif()
 include_directories(${PROJECT_SOURCE_DIR}/../sysdig/userspace/libscap)
 include_directories(${PROJECT_SOURCE_DIR}/../sysdig/userspace/libsinsp)
 
-add_executable(digwatch digwatch.cpp)
+add_executable(digwatch rules.cpp digwatch.cpp)
 
 target_link_libraries(digwatch sinsp)
 
diff --git a/userspace/digwatch/digwatch.cpp b/userspace/digwatch/digwatch.cpp
index 41e591c2..06f53676 100644
--- a/userspace/digwatch/digwatch.cpp
+++ b/userspace/digwatch/digwatch.cpp
@@ -8,15 +8,13 @@
 #include <algorithm>
 
 #include <sinsp.h>
-#include "lua_parser.h"
+#include "rules.h"
 #include "digwatch.h"
 #include "utils.h"
 
 #include <unistd.h>
 #include <getopt.h>
 
-lua_parser* g_lua_parser;
-
 static void usage();
 
 //
@@ -127,6 +125,7 @@ int digwatch_init(int argc, char **argv)
 {
 	int result;
 	sinsp* inspector = NULL;
+	digwatch_rules* rules = NULL;
 	int op;
 	uint64_t cnt = -1;
 	sinsp_evt::param_fmt event_buffer_format = sinsp_evt::PF_NORMAL;
@@ -234,9 +233,9 @@ int digwatch_init(int argc, char **argv)
 		//
 		sinsp_evt_formatter formatter(inspector, output_format);
 
-		g_lua_parser = new lua_parser(inspector, user_parser);
+		rules = new digwatch_rules(inspector, user_parser);
 
-		inspector->set_filter(g_lua_parser->m_filter);
+		inspector->set_filter(rules->get_filter());
 		inspector->open("");
 
 		cinfo = do_inspect(inspector,
diff --git a/userspace/digwatch/rules.cpp b/userspace/digwatch/rules.cpp
new file mode 100644
index 00000000..7eea6f19
--- /dev/null
+++ b/userspace/digwatch/rules.cpp
@@ -0,0 +1,45 @@
+#include "rules.h"
+
+extern "C" {
+#include "lua.h"
+#include "lualib.h"
+#include "lauxlib.h"
+}
+
+digwatch_rules::digwatch_rules(sinsp* inspector, string compiler_filename)
+{
+	m_lua_parser = new lua_parser(inspector);
+	m_ls = m_lua_parser->m_ls;
+
+	trim(compiler_filename);
+
+	ifstream is;
+	is.open(compiler_filename);
+	if(!is.is_open())
+	{
+		throw sinsp_exception("can't open file " + compiler_filename);
+	}
+
+	string scriptstr((istreambuf_iterator<char>(is)),
+			 istreambuf_iterator<char>());
+
+	//
+	// Load the compiler script
+	//
+	if(luaL_loadstring(m_ls, scriptstr.c_str()) || lua_pcall(m_ls, 0, 0, 0))
+	{
+		throw sinsp_exception("Failed to load script " +
+			compiler_filename + ": " + lua_tostring(m_ls, -1));
+	}
+}
+
+sinsp_filter* digwatch_rules::get_filter()
+{
+	return m_lua_parser->get_filter();
+}
+
+digwatch_rules::~digwatch_rules()
+{
+	delete m_lua_parser;
+}
+
diff --git a/userspace/digwatch/rules.h b/userspace/digwatch/rules.h
new file mode 100644
index 00000000..471a1490
--- /dev/null
+++ b/userspace/digwatch/rules.h
@@ -0,0 +1,17 @@
+#pragma once
+
+#include "sinsp.h"
+#include "lua_parser.h"
+
+class digwatch_rules
+{
+ public:
+	digwatch_rules(sinsp* inspector, string compiler_filename);
+	~digwatch_rules();
+	void load(string rules_filename);
+	sinsp_filter* get_filter();
+
+ private:
+	lua_parser* m_lua_parser;
+	lua_State* m_ls;
+};