fix chunked transfer encoding in keepalive mode

The two commits

  5162e3b
	"allow request handlers to disable chunked reponses"

and

  618493e
	"file: disable chunked encoding for file responses"

broke the chunked transfer encoding handling for proc responses in keep-alive
connections that followed a file response with http status 204 or 304.

The effect of this bug is that cgi responses following a 204 or 304 one where
sent neither in chunked encoding nor with a content-length header, causing
browsers to stall until the keep alive timeout was reached.

Fix the logic flaw by inverting the chunk prevention flag in the client state
and by testing the chunked encoding preconditions every time instead of
once upon client (re-)initialization.

Signed-off-by: Jo-Philipp Wich <[email protected]>

client.c

@@ -50,7 +50,7 @@ void uh_http_header(struct client *cl, int code, const char *summary)
 
 	cl->http_code = code;
 
-	if (!cl->request.respond_chunked)
+	if (!uh_use_chunked(cl))
 		enc = "";
 
 	if (r->connection_close)
@@ -188,8 +188,6 @@ static int client_parse_request(struct client *cl, char *data)
 	    !conf.http_keepalive)
 		req->connection_close = true;
 
-	req->respond_chunked = uh_use_chunked(cl);
-
 	return CLIENT_STATE_HEADER;
 }
 
@@ -261,7 +259,7 @@ static bool tls_redirect_check(struct client *cl)
 	else if ((ptr = strchr(host, ':')) != NULL)
 		*ptr = 0;
 
-	cl->request.respond_chunked = false;
+	cl->request.disable_chunked = true;
 	cl->request.connection_close = true;
 
 	uh_http_header(cl, 307, "Temporary Redirect");

file.c

@@ -614,7 +614,7 @@ static void uh_file_request(struct client *cl, const char *url,
 		if (fd < 0)
 			goto error;
 
-		req->respond_chunked = false;
+		req->disable_chunked = true;
 		cl->dispatch.file.hdr = tb;
 		uh_file_data(cl, pi, fd);
 		cl->dispatch.file.hdr = NULL;

uhttpd.h

@@ -112,7 +112,7 @@ struct http_request {
 	int content_length;
 	bool expect_cont;
 	bool connection_close;
-	bool respond_chunked;
+	bool disable_chunked;
 	uint8_t transfer_chunked;
 	const struct auth_realm *realm;
 };

utils.c

@@ -32,12 +32,12 @@ bool uh_use_chunked(struct client *cl)
 	if (cl->http_code == 204 || cl->http_code == 304)
 		return false;
 
-	return true;
+	return !cl->request.disable_chunked;
 }
 
 void uh_chunk_write(struct client *cl, const void *data, int len)
 {
-	bool chunked = cl->request.respond_chunked;
+	bool chunked = uh_use_chunked(cl);
 
 	if (cl->state == CLIENT_STATE_CLEANUP)
 		return;
@@ -60,7 +60,7 @@ void uh_chunk_vprintf(struct client *cl, const char *format, va_list arg)
 		return;
 
 	uloop_timeout_set(&cl->timeout, conf.network_timeout * 1000);
-	if (!cl->request.respond_chunked) {
+	if (!uh_use_chunked(cl)) {
 		ustream_vprintf(cl->us, format, arg);
 		return;
 	}
@@ -88,7 +88,7 @@ void uh_chunk_printf(struct client *cl, const char *format, ...)
 
 void uh_chunk_eof(struct client *cl)
 {
-	if (!cl->request.respond_chunked)
+	if (!uh_use_chunked(cl))
 		return;
 
 	if (cl->state == CLIENT_STATE_CLEANUP)