signal: handle shutdown properly

This addresses issues related to the mobile lnd builds, where
calling `stopDaemon` and subsequently calling LndMobile's `Start`
results in crash.

cmd/lncli/cmd_open_channel.go

@@ -18,7 +18,6 @@ import (
 	"github.com/btcsuite/btcutil"
 	"github.com/lightningnetwork/lnd/lnrpc"
 	"github.com/lightningnetwork/lnd/lnwallet/chanfunding"
-	"github.com/lightningnetwork/lnd/signal"
 	"github.com/urfave/cli"
 )
 
@@ -467,7 +466,7 @@ func openChannelPsbt(rpcCtx context.Context, ctx *cli.Context,
 	// the server.
 	go func() {
 		select {
-		case <-signal.ShutdownChannel():
+		case <-rpcCtx.Done():
 			fmt.Printf("\nInterrupt signal received.\n")
 			close(quit)
 

cmd/lncli/commands.go

@@ -41,14 +41,15 @@ const (
 )
 
 func getContext() context.Context {
-	if err := signal.Intercept(); err != nil {
+	shutdownInterceptor, err := signal.Intercept()
+	if err != nil {
 		_, _ = fmt.Fprintln(os.Stderr, err)
 		os.Exit(1)
 	}
 
 	ctxc, cancel := context.WithCancel(context.Background())
 	go func() {
-		<-signal.ShutdownChannel()
+		<-shutdownInterceptor.ShutdownChannel()
 		cancel()
 	}()
 	return ctxc