fix macOS dns issue

fix error handling

fix bash

Try fixing mac os dns set

core/cmd/nekobox_core/core_box.go

@@ -15,6 +15,7 @@ import (
 )
 
 var instance *boxbox.Box
+var needUnsetDNS bool
 var systemProxyController settings.SystemProxy
 var systemProxyAddr metadata.Socksaddr
 var instance_cancel context.CancelFunc

core/cmd/nekobox_core/grpc_box.go

@@ -8,9 +8,11 @@ import (
 	"github.com/sagernet/sing-box/experimental/clashapi"
 	"github.com/sagernet/sing/common/metadata"
 	"nekobox_core/internal/boxbox"
+	"nekobox_core/internal/sys"
 	grpc_server "nekobox_core/server"
 	"nekobox_core/server/gen"
 	"os"
+	"runtime"
 	"strings"
 	"time"
 
@@ -48,6 +50,13 @@ func (s *server) Start(ctx context.Context, in *gen.LoadConfigReq) (out *gen.Err
 	}
 
 	instance, instance_cancel, err = boxmain.Create([]byte(in.CoreConfig))
+	if runtime.GOOS == "darwin" && strings.Contains(in.CoreConfig, "utun") && err == nil {
+		err := sys.SetSystemDNS("192.18.0.2", instance.Router().InterfaceMonitor())
+		if err != nil {
+			log.Println("Failed to set system DNS:", err)
+		}
+		needUnsetDNS = true
+	}
 
 	if instance != nil {
 		// Logger
@@ -78,6 +87,13 @@ func (s *server) Stop(ctx context.Context, in *gen.EmptyReq) (out *gen.ErrorResp
 		return
 	}
 
+	if needUnsetDNS {
+		needUnsetDNS = false
+		err := sys.SetSystemDNS("Empty", instance.Router().InterfaceMonitor())
+		if err != nil {
+			log.Println("Failed to unset system DNS:", err)
+		}
+	}
 	instance.CloseWithTimeout(instance_cancel, time.Second*2, log.Println)
 
 	instance = nil

core/cmd/nekobox_core/internal/sys/set_dns_darwin.go

@@ -0,0 +1,40 @@
+package sys
+
+import (
+	tun "github.com/sagernet/sing-tun"
+	E "github.com/sagernet/sing/common/exceptions"
+	"github.com/sagernet/sing/common/shell"
+	"net/netip"
+	"strings"
+)
+
+func SetSystemDNS(addr string, interfaceMonitor tun.DefaultInterfaceMonitor) error {
+	interfaceName := interfaceMonitor.DefaultInterfaceName(netip.IPv4Unspecified())
+	interfaceDisplayName, err := getInterfaceDisplayName(interfaceName)
+	if err != nil {
+		return err
+	}
+
+	err = shell.Exec("networksetup", "-setdnsservers", interfaceDisplayName, addr).Attach().Run()
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+func getInterfaceDisplayName(name string) (string, error) {
+	content, err := shell.Exec("networksetup", "-listallhardwareports").ReadOutput()
+	if err != nil {
+		return "", err
+	}
+	for _, deviceSpan := range strings.Split(string(content), "Ethernet Address") {
+		if strings.Contains(deviceSpan, "Device: "+name) {
+			substr := "Hardware Port: "
+			deviceSpan = deviceSpan[strings.Index(deviceSpan, substr)+len(substr):]
+			deviceSpan = deviceSpan[:strings.Index(deviceSpan, "\n")]
+			return deviceSpan, nil
+		}
+	}
+	return "", E.New(name, " not found in networksetup -listallhardwareports")
+}

core/cmd/nekobox_core/internal/sys/set_dns_stub.go

@@ -0,0 +1,10 @@
+package sys
+
+import (
+	"errors"
+	tun "github.com/sagernet/sing-tun"
+)
+
+func SetSystemDNS(addr string, interfaceMonitor tun.DefaultInterfaceMonitor) error {
+	return errors.New("not implemented for this OS")
+}