Add remote signing binary

.gitignore

@@ -26,6 +26,8 @@ _testmain.go
 
 /lnd
 /lnd-debug
+/lndsigner
+/lndsigner-debug
 /lncli
 /lncli-debug
 /lnd-itest

Makefile

@@ -107,11 +107,12 @@ $(GOIMPORTS_BIN):
 # INSTALLATION
 # ============
 
-#? build: Build lnd and lncli binaries, place them in project directory
+#? build: Build lnd, lncli and lndsigner binaries, place them in project directory
 build:
-	@$(call print, "Building debug lnd and lncli.")
+	@$(call print, "Building debug lnd/lndsigner and lncli.")
 	$(GOBUILD) -tags="$(DEV_TAGS)" -o lnd-debug $(DEV_GCFLAGS) $(DEV_LDFLAGS) $(PKG)/cmd/lnd
 	$(GOBUILD) -tags="$(DEV_TAGS)" -o lncli-debug $(DEV_GCFLAGS) $(DEV_LDFLAGS) $(PKG)/cmd/lncli
+	$(GOBUILD) -tags="$(LND_SIGNER_TAGS)" -o lndsigner-debug $(DEV_GCFLAGS) $(DEV_LDFLAGS) $(PKG)/cmd/lndsigner
 
 #? build-itest: Build integration test binaries, place them in itest directory
 build-itest:
@@ -131,38 +132,40 @@ build-itest-race:
 	@$(call print, "Building itest binary for ${backend} backend.")
 	CGO_ENABLED=0 $(GOTEST) -v ./itest -tags="$(DEV_TAGS) $(RPC_TAGS) integration $(backend)" -c -o itest/itest.test$(EXEC_SUFFIX)
 
-#? install-binaries: Build and install lnd and lncli binaries, place them in $GOPATH/bin
+#? install-binaries: Build and install lnd, lncli and lndsigner binaries, place them in $GOPATH/bin
 install-binaries:
-	@$(call print, "Installing lnd and lncli.")
+	@$(call print, "Installing lnd/lndsigner and lncli.")
 	$(GOINSTALL) -tags="${tags}" -ldflags="$(RELEASE_LDFLAGS)" $(PKG)/cmd/lnd
 	$(GOINSTALL) -tags="${tags}" -ldflags="$(RELEASE_LDFLAGS)" $(PKG)/cmd/lncli
+	$(GOINSTALL) -tags="${LND_SIGNER_TAGS}" -ldflags="$(RELEASE_LDFLAGS)" $(PKG)/cmd/lndsigner
 
 #? manpages: generate and install man pages
 manpages:
 	@$(call print, "Generating man pages lncli.1 and lnd.1.")
 	./scripts/gen_man_pages.sh $(DESTDIR) $(PREFIX)
 
-#? install: Build and install lnd and lncli binaries and place them in $GOPATH/bin.
+#? install: Build and install lnd, lncli and lndsigner binaries and place them in $GOPATH/bin.
 install: install-binaries
 
 #? install-all: Performs all the same tasks as the install command along with generating and
 # installing the man pages for the lnd and lncli binaries. This command is useful in an
 # environment where a user has root access and so has write access to the man page directory.
 install-all: install manpages
 
-#? release-install: Build and install lnd and lncli release binaries, place them in $GOPATH/bin
+#? release-install: Build and install lnd, lncli and lndsigner binaries release binaries, place them in $GOPATH/bin
 release-install:
-	@$(call print, "Installing release lnd and lncli.")
+	@$(call print, "Installing release lnd/lndsigner and lncli.")
 	env CGO_ENABLED=0 $(GOINSTALL) -v -trimpath -ldflags="$(RELEASE_LDFLAGS)" -tags="$(RELEASE_TAGS)" $(PKG)/cmd/lnd
 	env CGO_ENABLED=0 $(GOINSTALL) -v -trimpath -ldflags="$(RELEASE_LDFLAGS)" -tags="$(RELEASE_TAGS)" $(PKG)/cmd/lncli
+	env CGO_ENABLED=0 $(GOINSTALL) -v -trimpath -ldflags="$(RELEASE_LDFLAGS)" -tags="$(LND_SIGNER_TAGS)" $(PKG)/cmd/lndsigner
 
 #? release: Build the full set of reproducible release binaries for all supported platforms
 # Make sure the generated mobile RPC stubs don't influence our vendor package
 # by removing them first in the clean-mobile target.
 release: clean-mobile
-	@$(call print, "Releasing lnd and lncli binaries.")
+	@$(call print, "Releasing lnd/lndsigner and lncli binaries.")
 	$(VERSION_CHECK)
-	./scripts/release.sh build-release "$(VERSION_TAG)" "$(BUILD_SYSTEM)" "$(RELEASE_TAGS)" "$(RELEASE_LDFLAGS)" "$(GO_VERSION)"
+	./scripts/release.sh build-release "$(VERSION_TAG)" "$(BUILD_SYSTEM)" "$(RELEASE_TAGS)" "$(LND_SIGNER_TAGS)" "$(RELEASE_LDFLAGS)" "$(GO_VERSION)"
 
 #? docker-release: Same as release but within a docker container to support reproducible builds on BSD/MacOS platforms
 docker-release:
@@ -427,7 +430,7 @@ mobile: ios android
 #? clean: Remove all generated files
 clean:
 	@$(call print, "Cleaning source.$(NC)")
-	$(RM) ./lnd-debug ./lncli-debug
+	$(RM) ./lnd-debug ./lndsigner-debug ./lncli-debug
 	$(RM) ./lnd-itest ./lncli-itest
 	$(RM) -r ./vendor .vendor-new
 

cmd/lndsigner/main.go

@@ -0,0 +1,46 @@
+package main
+
+import (
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/jessevdk/go-flags"
+	"github.com/lightningnetwork/lnd"
+	"github.com/lightningnetwork/lnd/signal"
+)
+
+func main() {
+	// Hook interceptor for os signals.
+	shutdownInterceptor, err := signal.Intercept()
+	if err != nil {
+		_, _ = fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+
+	// Load the signer configuration, and parse any command line options.
+	// This function will also set up logging properly.
+	loadedConfig, err := lnd.LoadSignerConfig(shutdownInterceptor)
+	if err != nil {
+		var flagsErr *flags.Error
+		if errors.As(err, &flagsErr) && flagsErr.Type == flags.ErrHelp {
+			// Help was requested, exit normally.
+			os.Exit(0)
+		}
+
+		// Print error if not due to help request.
+		err = fmt.Errorf("failed to load config: %w", err)
+		_, _ = fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+	implCfg := loadedConfig.ImplementationConfig(shutdownInterceptor)
+
+	// Call the "real" main in a nested manner so the defers will properly
+	// be executed in the case of a graceful shutdown.
+	if err = lnd.Main(
+		loadedConfig, lnd.ListenerCfg{}, implCfg, shutdownInterceptor,
+	); err != nil {
+		_, _ = fmt.Fprintln(os.Stderr, err)
+		os.Exit(1)
+	}
+}