allow to inherit unix domain sockets while online upgrade

src/core/ngx_connection.c

diff --git a/src/core/ngx_connection.c b/src/core/ngx_connection.c
index 9d064c5..3bd9cc6 100644
--- a/src/core/ngx_connection.c
+++ b/src/core/ngx_connection.c
@@ -117,11 +117,20 @@
 #if (NGX_HAVE_INET6)
         case AF_INET6:
              ls[i].addr_text_max_len = NGX_INET6_ADDRSTRLEN;
+             len = NGX_INET6_ADDRSTRLEN + sizeof(":65535") - 1;
+             break;
+#endif
+
+#if (NGX_HAVE_UNIX_DOMAIN)
+        case AF_UNIX:
+             ls[i].addr_text_max_len = NGX_UNIX_ADDRSTRLEN;
+             len = NGX_UNIX_ADDRSTRLEN;
              break;
 #endif
 
         case AF_INET:
              ls[i].addr_text_max_len = NGX_INET_ADDRSTRLEN;
+             len = NGX_INET_ADDRSTRLEN + sizeof(":65535") - 1;
              break;
 
         default:
@@ -132,8 +141,6 @@
             continue;
         }
 
-        len = ls[i].addr_text_max_len + sizeof(":65535") - 1;
-
         ls[i].addr_text.data = ngx_pnalloc(cycle->pool, len);
         if (ls[i].addr_text.data == NULL) {
             return NGX_ERROR;