chore: remove refs to deprecated io/ioutil

cmd/ssl/main.go

@@ -48,7 +48,7 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"time"
 
 	MQTT "github.com/eclipse/paho.mqtt.golang"
@@ -59,7 +59,7 @@ func NewTLSConfig() *tls.Config {
 	// Alternatively, manually add CA certificates to
 	// default openssl CA bundle.
 	certpool := x509.NewCertPool()
-	pemCerts, err := ioutil.ReadFile("samplecerts/CAfile.pem")
+	pemCerts, err := os.ReadFile("samplecerts/CAfile.pem")
 	if err == nil {
 		certpool.AppendCertsFromPEM(pemCerts)
 	}

filestore.go

@@ -19,7 +19,6 @@
 package mqtt
 
 import (
-	"io/ioutil"
 	"os"
 	"path"
 	"sort"
@@ -159,14 +158,23 @@ func (store *FileStore) Reset() {
 func (store *FileStore) all() []string {
 	var err error
 	var keys []string
-	var files fileInfos
 
 	if !store.opened {
 		ERROR.Println(STR, "trying to use file store, but not open")
 		return nil
 	}
-
-	files, err = ioutil.ReadDir(store.directory)
+	entries, err := os.ReadDir(store.directory)
+	if err != nil {
+		return nil
+	}
+	files := make(fileInfos, 0, len(entries))
+	for _, entry := range entries {
+		info, err := entry.Info()
+		if err != nil {
+			return nil
+		}
+		files = append(files, info)
+	}
 	chkerr(err)
 	sort.Sort(files)
 	for _, f := range files {

fvt_store_test.go

@@ -20,7 +20,6 @@ package mqtt
 
 import (
 	"bytes"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -250,7 +249,7 @@ func Test_FileStore_Get_Corrupted(t *testing.T) {
 		t.Fatalf("corrupt message not archived")
 	}
 
-	contents, err := ioutil.ReadFile(storedir + "/o.120.CORRUPT")
+	contents, err := os.ReadFile(storedir + "/o.120.CORRUPT")
 	chkerr(err)
 
 	if !bytes.Equal(exp, contents) {