http_proxy: Fix proxy CONNECT hang on pending data

- Check for pending data before waiting on the socket.

Bug: https://github.com/curl/curl/issues/1156
Reported-by: Adam Langley

1 files changed, 13 insertions, 0 deletions

diff --git a/lib/connect.c b/lib/connect.c
index 284726ae3..524d885eb 100644
--- a/lib/connect.c
+++ b/lib/connect.c
@@ -1404,3 +1404,16 @@ void Curl_conncontrol(struct connectdata *conn,
                                    should assign this bit */
   }
 }
+
+/* Data received can be cached at various levels, so check them all here. */
+bool Curl_conn_data_pending(struct connectdata *conn, int sockindex)
+{
+  int readable;
+
+  if(Curl_ssl_data_pending(conn, sockindex) ||
+     Curl_recv_has_postponed_data(conn, sockindex))
+    return true;
+
+  readable = SOCKET_READABLE(conn->sock[sockindex], 0);
+  return (readable > 0 && (readable & CURL_CSELECT_IN));
+}