Index: src/mod_fastcgi.c
===================================================================
--- src/mod_fastcgi.c	(revision 2907)
+++ src/mod_fastcgi.c	(working copy)
@@ -241,6 +241,14 @@
 	 */
 	unsigned short allow_xsendfile;
 
+	/*
+	 * If X-Sendfile or X-Sendfile2 is used and the file doesn't exist,
+	 * this module will send a "404 Not Found" error, just as lighttpd
+	 * would. The default is to send a "502 Bad Gateway" error,
+	 * indicating an error on the (possibly remote) FastCGI side.
+	 */
+	unsigned short allow_xsendfile_404;
+
 	ssize_t load; /* replace by host->load */
 
 	size_t max_id; /* corresponds most of the time to
@@ -1261,6 +1269,7 @@
 						{ "strip-request-uri",  NULL, T_CONFIG_STRING, T_CONFIG_SCOPE_CONNECTION },      /* 13 */
 						{ "kill-signal",        NULL, T_CONFIG_SHORT, T_CONFIG_SCOPE_CONNECTION },       /* 14 */
 						{ "fix-root-scriptname",   NULL, T_CONFIG_BOOLEAN, T_CONFIG_SCOPE_CONNECTION },  /* 15 */
+						{ "allow-x-send-file-404", NULL, T_CONFIG_BOOLEAN, T_CONFIG_SCOPE_CONNECTION },  /* 16 */
 
 						{ NULL,                NULL, T_CONFIG_UNSET, T_CONFIG_SCOPE_UNSET }
 					};
@@ -1285,6 +1294,7 @@
 					host->disable_time = 1;
 					host->break_scriptfilename_for_php = 0;
 					host->allow_xsendfile = 0; /* handle X-LIGHTTPD-send-file */
+					host->allow_xsendfile_404 = 0;
 					host->kill_signal = SIGTERM;
 					host->fix_root_path_name = 0;
 
@@ -1306,6 +1316,7 @@
 					fcv[13].destination = host->strip_request_uri;
 					fcv[14].destination = &(host->kill_signal);
 					fcv[15].destination = &(host->fix_root_path_name);
+					fcv[16].destination = &(host->allow_xsendfile_404);
 
 					if (0 != config_insert_values_internal(srv, da_host->value, fcv)) {
 						return HANDLER_ERROR;
@@ -2268,7 +2279,7 @@
 						if (p->conf.debug) {
 							log_error_write(srv, __FILE__, __LINE__, "ss", "Couldn't find range after filename:", filename);
 						}
-						return 1;
+						return 502;
 					}
 					buffer_copy_string_len(srv->tmp_buf, filename, range - filename);
 
@@ -2282,14 +2293,14 @@
 								"send-file error: couldn't get stat_cache entry for X-Sendfile2:",
 								srv->tmp_buf);
 						}
-						return 1;
+						return host->allow_xsendfile_404 ? 404 : 502;
 					} else if (!S_ISREG(sce->st.st_mode)) {
 						if (p->conf.debug) {
 							log_error_write(srv, __FILE__, __LINE__, "sb",
 								"send-file error: wrong filetype for X-Sendfile2:",
 								srv->tmp_buf);
 						}
-						return 1;
+						return 502;
 					}
 					/* found the file */
 
@@ -2314,7 +2325,7 @@
 						if (p->conf.debug) {
 							log_error_write(srv, __FILE__, __LINE__, "ss", "Couldn't decode range after filename:", filename);
 						}
-						return 1;
+						return 502;
 
 range_success: ;
 					}
@@ -2322,10 +2333,10 @@
 					/* no parameters accepted */
 
 					while (*pos == ' ') pos++;
-					if (*pos != '\0' && *pos != ',') return 1;
+					if (*pos != '\0' && *pos != ',') return 502;
 
 					range_len = end_range - begin_range + 1;
-					if (range_len < 0) return 1;
+					if (range_len < 0) return 502;
 					if (range_len != 0) {
 						http_chunk_append_file(srv, con, srv->tmp_buf, begin_range, range_len);
 					}
@@ -2484,7 +2495,7 @@
 
 static int fcgi_demux_response(server *srv, handler_ctx *hctx) {
 	int fin = 0;
-	int toread;
+	int toread, ret;
 	ssize_t r;
 
 	plugin_data *p    = hctx->plugin_data;
@@ -2596,8 +2607,8 @@
 				}
 
 				/* parse the response header */
-				if (fcgi_response_parse(srv, con, p, hctx->response_header)) {
-					con->http_status = 502;
+				if ((ret = fcgi_response_parse(srv, con, p, hctx->response_header))) {
+					con->http_status = ret;
 					hctx->send_content_body = 0;
 					con->file_started = 1;
 					break;
@@ -2635,13 +2646,20 @@
 						con->parsed_response |= HTTP_CONTENT_LENGTH;
 						con->response.content_length = sce->st.st_size;
 					} else {
-						log_error_write(srv, __FILE__, __LINE__, "sb",
-							"send-file error: couldn't get stat_cache entry for:",
-							ds->value);
-						con->http_status = 502;
-						hctx->send_content_body = 0;
-						con->file_started = 1;
-						break;
+						if (host->allow_xsendfile_404) {
+							con->http_status = 404;
+							hctx->send_content_body = 0;
+							con->file_started = 1;
+							break;
+						} else {
+							log_error_write(srv, __FILE__, __LINE__, "sb",
+								"send-file error: couldn't get stat_cache entry for:",
+								ds->value);
+							con->http_status = 502;
+							hctx->send_content_body = 0;
+							con->file_started = 1;
+							break;
+						}
 					}
 				}