diff --git a/client_https.go b/client_https.go
index a7b8775..ad4127e 100644
--- a/client_https.go
+++ b/client_https.go
@@ -4,7 +4,7 @@ import (
 	"bytes"
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"time"
 
@@ -45,7 +45,7 @@ func (c *httpclient) Exchange(msg *dns.Msg, upstream string) (*dns.Msg, int, err
 		return nil, 0, fmt.Errorf("http error %d", resp.StatusCode)
 	}
 
-	data, err = ioutil.ReadAll(resp.Body)
+	data, err = io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, 0, err
 	}
diff --git a/config.go b/config.go
index 17b636a..7d2a138 100644
--- a/config.go
+++ b/config.go
@@ -1,7 +1,7 @@
 package main
 
 import (
-	"io/ioutil"
+	"os"
 
 	"github.com/go-yaml/yaml"
 )
@@ -21,7 +21,7 @@ type listen struct {
 }
 
 func loadConfig(f string) (*conf, error) {
-	data, err := ioutil.ReadFile(f)
+	data, err := os.ReadFile(f)
 	if err != nil {
 		return nil, err
 	}
diff --git a/main.go b/main.go
index 36e4ece..68d3410 100644
--- a/main.go
+++ b/main.go
@@ -61,9 +61,7 @@ func main() {
 	makeServers(cfg)
 	ch := make(chan os.Signal, 2)
 	signal.Notify(ch, syscall.SIGINT, syscall.SIGTERM)
-	select {
-	case s := <-ch:
-		log.Errorf("received signal %s, exit...", s)
-	}
+	s := <-ch
+	log.Errorf("received signal %s, exit...", s)
 	log.Println("exit.")
 }
diff --git a/server_https.go b/server_https.go
index b18297d..6c6d6d3 100644
--- a/server_https.go
+++ b/server_https.go
@@ -1,7 +1,7 @@
 package main
 
 import (
-	"io/ioutil"
+	"io"
 	"net/http"
 
 	log "github.com/fangdingjun/go-log/v5"
@@ -26,7 +26,7 @@ func (srv *server) handleHTTPReq(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
-	data, err := ioutil.ReadAll(r.Body)
+	data, err := io.ReadAll(r.Body)
 	if err != nil {
 		log.Errorln("read request body", err)
 		http.Error(w, "read request failed", http.StatusBadRequest)