From 51095fe2ba9d109e34251d7221fe0bf768ec749b Mon Sep 17 00:00:00 2001 From: Takashi Yano Date: Fri, 4 Mar 2022 22:02:35 +0900 Subject: [PATCH] Cygwin: pty: Fix a possible race issue in initialization of pcon. - Currently, tty::pcon_start flag is cleared before transfer_input() in master::write(), however, the code in setup_pseudoconsole() waits for transfer_input() using tty::pcon_start. This possibly causes the race issue. The patch fixes this potential issue. --- winsup/cygwin/fhandler_tty.cc | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc index cba25ee84..3ed84709e 100644 --- a/winsup/cygwin/fhandler_tty.cc +++ b/winsup/cygwin/fhandler_tty.cc @@ -3215,7 +3215,8 @@ fhandler_pty_slave::setup_pseudoconsole () get_ttyp ()->pcon_start_pid = myself->pid; WriteFile (get_output_handle (), "\033[6n", 4, &n, NULL); ReleaseMutex (input_mutex); - while (get_ttyp ()->pcon_start) + while (get_ttyp ()->pcon_start_pid) + /* wait for completion of transfer_input() in master::write(). */ Sleep (1); } /* Attach to the pseudo console which already exits. */