Fixes issue #18

Dont check for sudo first, try to open fd

Author: MarinX

keylogger.go

@@ -35,12 +35,15 @@ var allowedDevices = devices{"keyboard", "logitech mx keys"}
 // New creates a new keylogger for a device path
 func New(devPath string) (*KeyLogger, error) {
 	k := &KeyLogger{}
-	if !k.IsRoot() {
-		return nil, errors.New("Must be run as root")
-	}
 	fd, err := os.OpenFile(devPath, os.O_RDWR, os.ModeCharDevice)
+	if err != nil {
+		if os.IsPermission(err) && !k.IsRoot() {
+			return nil, errors.New("permission denied. run with root permission or use a user with access to " + devPath)
+		}
+		return nil, err
+	}
 	k.fd = fd
-	return k, err
+	return k, nil
 }
 
 // FindKeyboardDevice by going through each device registered on OS

keylogger_test.go

@@ -1,6 +1,7 @@
 package keylogger
 
 import (
+	"os"
 	"testing"
 )
 
@@ -38,3 +39,26 @@ func TestBufferParser(t *testing.T) {
 		return
 	}
 }
+
+func TestWithPermission(t *testing.T) {
+	fd, err := os.CreateTemp("", "*")
+	if err != nil {
+		t.Fatal(err)
+	}
+	// try to create new keylogger with file descriptor which has the permission
+	k, err := New(fd.Name())
+	if err != nil {
+		t.Fatal(err)
+	}
+	k.Close()
+	fd.Close()
+
+	// try to create new keylogger with file descriptor which has no permission
+	_, err = New("/dev/tty0")
+	if err == nil {
+		t.Fatal("expected error, got nil")
+	}
+	if err.Error() != "permission denied. run with root permission or use a user with access to /dev/tty0" {
+		t.Fatalf("unexpected error: %v", err)
+	}
+}