PMM-13054 Fix linter errors

managed/services/supervisord/logs.go

@@ -272,15 +272,15 @@ func (l *Logs) victoriaMetricsTargets(ctx context.Context) ([]byte, error) {
 // and returns them together with modification time.
 func readLog(name string, readLines int) ([]byte, time.Time, error) {
 	var (
-		m        time.Time
-		res      []byte
-		maxLines int
+		m         time.Time
+		res       []byte
+		lineCount int
 	)
-	f, err := os.Open(name)
+	f, err := os.Open(name) //nolint:gosec
 	if err != nil {
 		return nil, m, errors.WithStack(err)
 	}
-	defer f.Close() //nolint:gosec,errcheck
+	defer f.Close() //nolint:errcheck
 
 	fi, err := f.Stat()
 	if err != nil {
@@ -291,17 +291,17 @@ func readLog(name string, readLines int) ([]byte, time.Time, error) {
 	switch readLines {
 	case 0:
 		// no parameter passed, use the default line count
-		maxLines = maxLogReadLines
-		res = make([]byte, maxLines)
+		lineCount = maxLogReadLines
 	case -1:
 		// unlimited number of lines
 	default:
-		maxLines = readLines
-		res = make([]byte, maxLines)
+		lineCount = readLines
 	}
 
+	res = make([]byte, 0)
+
 	reader := bufio.NewReader(f)
-	for maxLines >= 0 {
+	for lineCount >= 0 {
 		b, err := reader.ReadBytes('\n')
 		if err == io.EOF {
 			// A special case when the last line does not end with a new line
@@ -318,7 +318,8 @@ func readLog(name string, readLines int) ([]byte, time.Time, error) {
 		}
 
 		if readLines != -1 {
-			maxLines--
+			// Do not decrease the counter for unlimited line count
+			lineCount--
 		}
 	}