allow to configure rules and config file paths

 - Added cli option -config-file to specify an alternate path to the
   config file.
 - Allow to configure rules path from the configuration file (cli option
   takes precedence).
 - Default options are now /etc/opensnitchd/rules and
   /etc/opensnitchd/default-config.json. Previously the default rules
   directory was "rules" (relative path).

Closes #449

(cherry picked from commit 211c864)

daemon/main.go

@@ -50,6 +50,7 @@ import (
 	"github.com/evilsocket/opensnitch/daemon/rule"
 	"github.com/evilsocket/opensnitch/daemon/statistics"
 	"github.com/evilsocket/opensnitch/daemon/ui"
+	"github.com/evilsocket/opensnitch/daemon/ui/config"
 	"github.com/evilsocket/opensnitch/daemon/ui/protocol"
 )
 
@@ -60,7 +61,8 @@ var (
 	logFile           = ""
 	logUTC            = true
 	logMicro          = false
-	rulesPath         = "rules"
+	rulesPath         = "/etc/opensnitchd/rules/"
+	configFile        = "/etc/opensnitchd/default-config.json"
 	noLiveReload      = false
 	queueNum          = 0
 	repeatQueueNum    int //will be set later to queueNum + 1
@@ -102,6 +104,7 @@ func init() {
 	flag.IntVar(&workers, "workers", workers, "Number of concurrent workers.")
 	flag.BoolVar(&noLiveReload, "no-live-reload", debug, "Disable rules live reloading.")
 
+	flag.StringVar(&configFile, "config-file", configFile, "Path to the daemon configuration file.")
 	flag.StringVar(&logFile, "log-file", logFile, "Write logs to this file instead of the standard output.")
 	flag.BoolVar(&logUTC, "log-utc", logUTC, "Write logs output with UTC timezone (enabled by default).")
 	flag.BoolVar(&logMicro, "log-micro", logMicro, "Write logs output with microsecond timestamp (disabled by default).")
@@ -114,6 +117,27 @@ func init() {
 	flag.StringVar(&memProfile, "mem-profile", memProfile, "Write memory profile to this file.")
 }
 
+// Load configuration file from disk, by default from /etc/opensnitchd/default-config.json,
+// or from the path specified by configFile.
+// This configuration will be loaded again by uiClient(), in order to monitor it for changes.
+func loadDiskConfiguration() (*config.Config, error) {
+	if configFile == "" {
+		return nil, fmt.Errorf("Configuration file cannot be empty")
+	}
+
+	raw, err := config.Load(configFile)
+	if err != nil || len(raw) == 0 {
+		return nil, fmt.Errorf("Error loading configuration %s: %s", configFile, err)
+	}
+	clientConfig, err := config.Parse(raw)
+	if err != nil {
+		return nil, fmt.Errorf("Error parsing configuration %s: %s", configFile, err)
+	}
+
+	log.Info("Loading configuration file %s ...", configFile)
+	return &clientConfig, nil
+}
+
 func overwriteLogging() bool {
 	return debug || warning || important || errorlog || logFile != "" || logMicro
 }
@@ -482,6 +506,17 @@ func main() {
 
 	log.Important("Starting %s v%s", core.Name, core.Version)
 
+	cfg, err := loadDiskConfiguration()
+	if err != nil {
+		log.Fatal("%s", err)
+	}
+	if err == nil && cfg.Rules.Path != "" {
+		rulesPath = cfg.Rules.Path
+	}
+	if rulesPath == "" {
+		log.Fatal("rules path cannot be empty")
+	}
+
 	rulesPath, err := core.ExpandPath(rulesPath)
 	if err != nil {
 		log.Fatal("Error accessing rules path (does it exist?): %s", err)
@@ -490,14 +525,15 @@ func main() {
 	setupSignals()
 
 	log.Info("Loading rules from %s ...", rulesPath)
-	if rules, err = rule.NewLoader(!noLiveReload); err != nil {
+	rules, err = rule.NewLoader(!noLiveReload)
+	if err != nil {
 		log.Fatal("%s", err)
 	} else if err = rules.Load(rulesPath); err != nil {
 		log.Fatal("%s", err)
 	}
 	stats = statistics.New(rules)
 	loggerMgr = loggers.NewLoggerManager()
-	uiClient = ui.NewClient(uiSocket, stats, rules, loggerMgr)
+	uiClient = ui.NewClient(uiSocket, configFile, stats, rules, loggerMgr)
 
 	// prepare the queue
 	setupWorkers()

daemon/rule/loader.go

@@ -64,11 +64,11 @@ func (l *Loader) GetAll() map[string]*Rule {
 // Load loads rules files from disk.
 func (l *Loader) Load(path string) error {
 	if core.Exists(path) == false {
-		return fmt.Errorf("Path '%s' does not exist\nCreate it in if you want to save rules to disk", path)
+		return fmt.Errorf("Path '%s' does not exist\nCreate it if you want to save rules to disk", path)
 	}
 	path, err := core.ExpandPath(path)
 	if err != nil {
-		return fmt.Errorf("Error accessing rules path: %s.\nCreate it in if you want to save rules to disk", err)
+		return fmt.Errorf("Error accessing rules path: %s.\nCreate it if you want to save rules to disk", err)
 	}
 
 	expr := filepath.Join(path, "*.json")

daemon/ui/client.go

@@ -59,7 +59,10 @@ type Client struct {
 }
 
 // NewClient creates and configures a new client.
-func NewClient(socketPath string, stats *statistics.Statistics, rules *rule.Loader, loggers *loggers.LoggerManager) *Client {
+func NewClient(socketPath, localConfigFile string, stats *statistics.Statistics, rules *rule.Loader, loggers *loggers.LoggerManager) *Client {
+	if localConfigFile != "" {
+		configFile = localConfigFile
+	}
 	c := &Client{
 		stats:        stats,
 		rules:        rules,

daemon/ui/config/config.go

@@ -44,19 +44,25 @@ type serverConfig struct {
 	Loggers        []loggers.LoggerConfig `json:"Loggers"`
 }
 
+type rulesOptions struct {
+	Path            string `json:"Path"`
+	EnableChecksums bool   `json:"EnableChecksums"`
+}
+
 // Config holds the values loaded from configFile
 type Config struct {
 	sync.RWMutex
 	Server            serverConfig           `json:"Server"`
+	Stats             statistics.StatsConfig `json:"Stats"`
+	Rules             rulesOptions           `json:"Rules"`
 	DefaultAction     string                 `json:"DefaultAction"`
 	DefaultDuration   string                 `json:"DefaultDuration"`
-	InterceptUnknown  bool                   `json:"InterceptUnknown"`
 	ProcMonitorMethod string                 `json:"ProcMonitorMethod"`
+	Firewall          string                 `json:"Firewall"`
 	LogLevel          *uint32                `json:"LogLevel"`
+	InterceptUnknown  bool                   `json:"InterceptUnknown"`
 	LogUTC            bool                   `json:"LogUTC"`
 	LogMicro          bool                   `json:"LogMicro"`
-	Firewall          string                 `json:"Firewall"`
-	Stats             statistics.StatsConfig `json:"Stats"`
 }
 
 // Parse determines if the given configuration is ok.