server_name $hostname

src/http/ngx_http_core_module.c

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
index 5e682f2..693a3cb 100644
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -3682,7 +3682,13 @@
         sn->regex = NULL;
 #endif
         sn->server = cscf;
-        sn->name = value[i];
+
+        if (ngx_strcasecmp(value[i].data, (u_char *) "$hostname") == 0) {
+            sn->name = cf->cycle->hostname;
+
+        } else {
+            sn->name = value[i];
+        }
 
         if (value[i].data[0] != '~') {
             ngx_strlow(sn->name.data, sn->name.data, sn->name.len);