Create missing directories before writing certpair.

sockets.go

@@ -37,6 +37,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"path/filepath"
 	"runtime"
 	"sync"
 	"time"
@@ -169,6 +170,17 @@ func newServer(listenAddrs []string) (*server, error) {
 func genCertPair(certFile, keyFile string) error {
 	log.Infof("Generating TLS certificates...")
 
+	// Create directories for cert and key files if they do not yet exist.
+	certDir, _ := filepath.Split(certFile)
+	keyDir, _ := filepath.Split(keyFile)
+	if err := os.MkdirAll(certDir, 0700); err != nil {
+		return err
+	}
+	if err := os.MkdirAll(keyDir, 0700); err != nil {
+		return err
+	}
+
+	// Generate cert pair.
 	org := "btcwallet autogenerated cert"
 	validUntil := time.Now().Add(10 * 365 * 24 * time.Hour)
 	cert, key, err := btcutil.NewTLSCertPair(org, validUntil, nil)