# HG changeset patch
# User Sergey Kandaurov <pluknet@nginx.com>
# Date 1375182286 -14400
# Node ID 03ff140582729a2b35cee7c235bf025cb0f97525
# Parent  e8bca839762561e34c7c36f5b5398fe361e5cd82
Added safety belt for the case of sending header twice.

The aforementioned situation is abnormal per se and as such it now forces
request termination with appropriate error message.

diff --git a/src/http/ngx_http_core_module.c b/src/http/ngx_http_core_module.c
--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -1933,6 +1933,12 @@ ngx_http_send_response(ngx_http_request_
 ngx_int_t
 ngx_http_send_header(ngx_http_request_t *r)
 {
+    if (r->header_sent) {
+        ngx_log_error(NGX_LOG_ALERT, r->connection->log, 0,
+                      "header already sent");
+        return NGX_ERROR;
+    }
+
     if (r->err_status) {
         r->headers_out.status = r->err_status;
         r->headers_out.status_line.len = 0;