 +
 +        } else {
 +            out .= "\"\""
++        }
++
++        if (ngx_buf_in_file(buf)) {
++            out .= sprintf("<in_file:%d-%d>", ngx_buf_file_pos(buf),
++                           ngx_buf_file_last(buf))
 +        }
 +
 +        if (ngx_buf_last_buf(buf)) {

diff --git a/README b/README
index 2f68e14..4f2c4a7 100644
--- a/README
+++ b/README
@@ -1,3 +1,40 @@
+This is an Nginx fork that adds dtrace USDT probes.
 
-Documentation is available at http://nginx.org
+This is still under development and not usable yet.
+
+Installation:
+
+    ./configure --with-dtrace-probes \

+}
+
+
+function ngx_buf_in_file(b)
+{
+    return @cast(b, "ngx_buf_t", "NGX_SBIN_PATH")->in_file
+}
+
+
+function ngx_buf_last_buf(b)
+{
+    return @cast(b, "ngx_buf_t", "/home/agentzh/git/lua-nginx-module/work/nginx/sbin/nginx")->last_buf
