Wrap Logger to make disabling output more efficient

Instead of using SetOutput(ioutil.Discard), which means
that Printf is still called for every debug message,
use a simple and fast boolean check.

Streaming write performance improves from 86 to 93 MB/s.

cryptfs/config_test.go

@@ -2,7 +2,6 @@ package cryptfs
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"testing"
 	"time"
@@ -35,7 +34,7 @@ func TestLoadV2(t *testing.T) {
 
 func TestLoadV2PwdError(t *testing.T) {
 	if !testing.Verbose() {
-		Warn.SetOutput(ioutil.Discard)
+		Warn.Enabled = false
 	}
 	_, _, err := LoadConfFile("config_test/v2.conf", "wrongpassword")
 	Warn.SetOutput(os.Stderr)

cryptfs/cryptfs.go

@@ -9,6 +9,8 @@ import (
 )
 
 const (
+	PROGRAM_NAME = "gocryptfs"
+
 	DEFAULT_PLAINBS = 4096
 	KEY_LEN         = 32 // AES-256
 	AUTH_TAG_LEN    = 16

cryptfs/log.go

@@ -2,8 +2,8 @@ package cryptfs
 
 import (
 	"encoding/json"
-	"io/ioutil"
 	"log"
+	"log/syslog"
 	"os"
 )
 
@@ -16,19 +16,45 @@ func JSONDump(obj interface{}) string {
 	}
 }
 
-// As defined by http://elinux.org/Debugging_by_printing#Log_Levels
+// toggledLogger - a Logger than can be enabled and disabled
+type toggledLogger struct {
+	Enabled bool
+	*log.Logger
+}
 
+func (l *toggledLogger) Printf(format string, v ...interface{}) {
+	if !l.Enabled {
+		return
+	}
+	l.Logger.Printf(format, v...)
+}
+func (l *toggledLogger) Println(v ...interface{}) {
+	if !l.Enabled {
+		return
+	}
+	l.Logger.Println(v...)
+}
+func (l *toggledLogger) SwitchToSyslog(p syslog.Priority) {
+	w, err := syslog.New(p, PROGRAM_NAME)
+	if err != nil {
+		Warn.Printf("Cannot switch 0x%02x to syslog: %v", p, err)
+	} else {
+		l.SetOutput(w)
+	}
+}
+
+// As defined by http://elinux.org/Debugging_by_printing#Log_Levels
 // Debug messages
-var Debug *log.Logger
+var Debug *toggledLogger
 
 // Informational message e.g. startup information
-var Info *log.Logger
+var Info *toggledLogger
 
 // A warning, meaning nothing serious by itself but might indicate problems
-var Warn *log.Logger
+var Warn *toggledLogger
 
 func init() {
-	Debug = log.New(ioutil.Discard, "", 0)
-	Info = log.New(os.Stdout, "", 0)
-	Warn = log.New(os.Stderr, "", 0)
+	Debug = &toggledLogger{false, log.New(os.Stdout, "", 0)}
+	Info = &toggledLogger{true, log.New(os.Stdout, "", 0)}
+	Warn = &toggledLogger{true, log.New(os.Stderr, "", 0)}
 }

daemonize.go

@@ -2,14 +2,10 @@ package main
 
 import (
 	"fmt"
-	"log"
-	"log/syslog"
 	"os"
 	"os/exec"
 	"os/signal"
 	"syscall"
-
-	"github.com/rfjakob/gocryptfs/cryptfs"
 )
 
 // The child sends us USR1 if the mount was successful
@@ -50,13 +46,3 @@ func forkChild() {
 	// The child exited with 0 - let's do the same.
 	os.Exit(0)
 }
-
-// Switch one Logger to syslog
-func switchToSyslog(l *log.Logger, p syslog.Priority) {
-	w, err := syslog.New(p, PROGRAM_NAME)
-	if err != nil {
-		cryptfs.Warn.Printf("Cannot switch 0x%02x to syslog: %v", p, err)
-	} else {
-		l.SetOutput(w)
-	}
-}

main.go

@@ -4,7 +4,6 @@ import (
 	"encoding/json"
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"log/syslog"
 	"os"
 	"os/exec"
@@ -26,8 +25,6 @@ import (
 )
 
 const (
-	PROGRAM_NAME = "gocryptfs"
-
 	// Exit codes
 	ERREXIT_USAGE      = 1
 	ERREXIT_MOUNT      = 3
@@ -77,15 +74,15 @@ func initDir(args *argContainer) {
 
 	cryptfs.Info.Printf(colorGreen + "The filesystem has been created successfully." + colorReset)
 	cryptfs.Info.Printf(colorGrey+"You can now mount it using: %s %s MOUNTPOINT"+colorReset,
-		PROGRAM_NAME, args.cipherdir)
+		cryptfs.PROGRAM_NAME, args.cipherdir)
 	os.Exit(0)
 }
 
 func usageText() {
 	printVersion()
 	fmt.Printf("\n")
-	fmt.Printf("Usage: %s -init|-passwd [OPTIONS] CIPHERDIR\n", PROGRAM_NAME)
-	fmt.Printf("  or   %s [OPTIONS] CIPHERDIR MOUNTPOINT\n", PROGRAM_NAME)
+	fmt.Printf("Usage: %s -init|-passwd [OPTIONS] CIPHERDIR\n", cryptfs.PROGRAM_NAME)
+	fmt.Printf("  or   %s [OPTIONS] CIPHERDIR MOUNTPOINT\n", cryptfs.PROGRAM_NAME)
 	fmt.Printf("\nOptions:\n")
 	flagSet.PrintDefaults()
 }
@@ -101,9 +98,9 @@ func loadConfig(args *argContainer) (masterkey []byte, confFile *cryptfs.ConfFil
 	fmt.Printf("Password: ")
 	pw := readPassword(args.extpass)
 	cryptfs.Info.Printf("Decrypting master key... ")
-	cryptfs.Warn.SetOutput(ioutil.Discard) // Silence DecryptBlock() error messages on incorrect password
+	cryptfs.Warn.Enabled = false // Silence DecryptBlock() error messages on incorrect password
 	masterkey, confFile, err = cryptfs.LoadConfFile(args.config, pw)
-	cryptfs.Warn.SetOutput(os.Stderr)
+	cryptfs.Warn.Enabled = true
 	if err != nil {
 		fmt.Println(err)
 		fmt.Println(colorRed + "Wrong password." + colorReset)
@@ -132,7 +129,7 @@ func changePassword(args *argContainer) {
 // printVersion - print a version string like
 // "gocryptfs v0.3.1-31-g6736212-dirty; on-disk format 2"
 func printVersion() {
-	fmt.Printf("%s %s; on-disk format %d\n", PROGRAM_NAME, GitVersion, cryptfs.HEADER_CURRENT_VERSION)
+	fmt.Printf("%s %s; on-disk format %d\n", cryptfs.PROGRAM_NAME, GitVersion, cryptfs.HEADER_CURRENT_VERSION)
 }
 
 func main() {
@@ -142,7 +139,7 @@ func main() {
 	setupColors()
 
 	// Parse command line arguments
-	flagSet = flag.NewFlagSet(PROGRAM_NAME, flag.ExitOnError)
+	flagSet = flag.NewFlagSet(cryptfs.PROGRAM_NAME, flag.ExitOnError)
 	flagSet.Usage = usageText
 	flagSet.BoolVar(&args.debug, "debug", false, "Enable debug output")
 	flagSet.BoolVar(&args.fusedebug, "fusedebug", false, "Enable fuse library debug output")
@@ -195,7 +192,7 @@ func main() {
 	}
 	// "-q"
 	if args.quiet {
-		cryptfs.Info.SetOutput(ioutil.Discard)
+		cryptfs.Info.Enabled = false
 	}
 	// "-config"
 	if args.config != "" {
@@ -226,7 +223,7 @@ func main() {
 	// "-init"
 	if args.init {
 		if flagSet.NArg() > 1 {
-			fmt.Printf("Usage: %s -init [OPTIONS] CIPHERDIR\n", PROGRAM_NAME)
+			fmt.Printf("Usage: %s -init [OPTIONS] CIPHERDIR\n", cryptfs.PROGRAM_NAME)
 			os.Exit(ERREXIT_USAGE)
 		}
 		initDir(&args) // does not return
@@ -234,7 +231,7 @@ func main() {
 	// "-passwd"
 	if args.passwd {
 		if flagSet.NArg() > 1 {
-			fmt.Printf("Usage: %s -passwd [OPTIONS] CIPHERDIR\n", PROGRAM_NAME)
+			fmt.Printf("Usage: %s -passwd [OPTIONS] CIPHERDIR\n", cryptfs.PROGRAM_NAME)
 			os.Exit(ERREXIT_USAGE)
 		}
 		changePassword(&args) // does not return
@@ -281,13 +278,9 @@ func main() {
 	if args.notifypid > 0 {
 		sendUsr1(args.notifypid)
 
-		if !args.quiet {
-			switchToSyslog(cryptfs.Info, syslog.LOG_USER|syslog.LOG_INFO)
-		}
-		if args.debug {
-			switchToSyslog(cryptfs.Debug, syslog.LOG_USER|syslog.LOG_DEBUG)
-		}
-		switchToSyslog(cryptfs.Warn, syslog.LOG_USER|syslog.LOG_WARNING)
+		cryptfs.Info.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_INFO)
+		cryptfs.Info.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_DEBUG)
+		cryptfs.Info.SwitchToSyslog(syslog.LOG_USER | syslog.LOG_WARNING)
 	}
 	// Wait for SIGINT in the background and unmount ourselves if we get it.
 	// This prevents a dangling "Transport endpoint is not connected" mountpoint.