nghttpx: Use std::string for Downstream::backend_tls_sni_name

src/shrpx_config.cc

@@ -1599,7 +1599,7 @@ int parse_config(const char *opt, const char *optarg,
 
     return 0;
   case SHRPX_OPTID_BACKEND_TLS_SNI_FIELD:
-    mod_config()->backend_tls_sni_name = strcopy(optarg);
+    mod_config()->backend_tls_sni_name = optarg;
 
     return 0;
   case SHRPX_OPTID_PID_FILE:

src/shrpx_config.h

@@ -310,6 +310,7 @@ struct Config {
   // field.  This is only used when user defined static obfuscated
   // string is provided.
   std::string forwarded_for_obfuscated;
+  std::string backend_tls_sni_name;
   std::chrono::seconds tls_session_timeout;
   ev_tstamp http2_upstream_read_timeout;
   ev_tstamp upstream_read_timeout;
@@ -329,7 +330,6 @@ struct Config {
   std::unique_ptr<char[]> private_key_passwd;
   std::unique_ptr<char[]> cert_file;
   std::unique_ptr<char[]> dh_param_file;
-  std::unique_ptr<char[]> backend_tls_sni_name;
   std::unique_ptr<char[]> pid_file;
   std::unique_ptr<char[]> conf_path;
   std::unique_ptr<char[]> ciphers;

src/shrpx_http2_session.cc

@@ -335,8 +335,8 @@ int Http2Session::initiate_connection() {
       }
 
       const char *sni_name = nullptr;
-      if (get_config()->backend_tls_sni_name) {
-        sni_name = get_config()->backend_tls_sni_name.get();
+      if (!get_config()->backend_tls_sni_name.empty()) {
+        sni_name = get_config()->backend_tls_sni_name.c_str();
       } else {
         sni_name = downstream_addr.host.c_str();
       }

src/shrpx_ssl.cc

@@ -971,10 +971,11 @@ int check_cert(SSL *ssl, const DownstreamAddr *addr) {
                << X509_verify_cert_error_string(verify_res);
     return -1;
   }
-  auto hostname = get_config()->backend_tls_sni_name
-                      ? get_config()->backend_tls_sni_name.get()
-                      : addr->host.c_str();
-  if (verify_hostname(cert, hostname, strlen(hostname), &addr->addr) != 0) {
+  auto hostname = !get_config()->backend_tls_sni_name.empty()
+                      ? StringAdaptor(get_config()->backend_tls_sni_name)
+                      : StringAdaptor(addr->host);
+  if (verify_hostname(cert, hostname.c_str(), hostname.size(), &addr->addr) !=
+      0) {
     LOG(ERROR) << "Certificate verification failed: hostname does not match";
     return -1;
   }