From 3cd747f77bdedb8ebbb13f9072871388c12ae876 Mon Sep 17 00:00:00 2001
From: Khashayar Fereidani <info@fereidani.com>
Date: Wed, 24 Jun 2026 09:11:03 +0000
Subject: [PATCH 1/2] Fix non-constant format string in buffer length error.

---
 ethr.go | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/ethr.go b/ethr.go
index d1a9c21..cf510c8 100644
--- a/ethr.go
+++ b/ethr.go
@@ -206,7 +206,7 @@ func main() {
 		}
 		bufLen := unitToNumber(*bufLenStr)
 		if bufLen == 0 {
-			printUsageError(fmt.Sprintf("Invalid length specified: %s" + *bufLenStr))
+			printUsageError(fmt.Sprintf("Invalid length specified: %s", *bufLenStr))
 		}
 
 		// Check specific bwRate if any.

From 631c64f78ae036dabce61dea737245e6b3c74218 Mon Sep 17 00:00:00 2001
From: Khashayar Fereidani <info@fereidani.com>
Date: Wed, 24 Jun 2026 09:11:03 +0000
Subject: [PATCH 2/2] Close log file deterministically on shutdown.

---
 log.go | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/log.go b/log.go
index 9774b23..fb81d53 100644
--- a/log.go
+++ b/log.go
@@ -10,6 +10,7 @@ import (
 	"fmt"
 	"log"
 	"os"
+	"sync"
 	"time"
 )
 
@@ -60,6 +61,8 @@ type logTestResults struct {
 
 var loggingActive = false
 var logChan = make(chan string, 64)
+var logDone = make(chan struct{})
+var logFiniOnce sync.Once
 
 func logInit(fileName string) {
 	if fileName == "" {
@@ -77,15 +80,25 @@ func logInit(fileName string) {
 }
 
 func logFini() {
-	loggingActive = false
+	// Signal runLogger to stop. Without this the goroutine blocks forever on
+	// the logChan receive and the log file is never closed. The once guard
+	// keeps logFini safe to call more than once.
+	logFiniOnce.Do(func() {
+		loggingActive = false
+		close(logDone)
+	})
 }
 
 func runLogger(logFile *os.File) {
-	for loggingActive {
-		s := <-logChan
-		log.Println(s)
+	for {
+		select {
+		case <-logDone:
+			_ = logFile.Close()
+			return
+		case s := <-logChan:
+			log.Println(s)
+		}
 	}
-	logFile.Close()
 }
 
 func logMsg(prefix, msg string) {