[newlib-cygwin/cygwin-3_3-branch] Cygwin: pty: Fix memory leak in master_fwd_thread.

[Takashi Yano <tyan0@sourceware.org>]

https://sourceware.org/git/gitweb.cgi?p=newlib-cygwin.git;h=4610a7e1d5433875bf37d853ccd500c1a61abba3

commit 4610a7e1d5433875bf37d853ccd500c1a61abba3
Author: Takashi Yano <takashi.yano@nifty.ne.jp>
Date:   Thu Jan 13 18:18:00 2022 +0900

    Cygwin: pty: Fix memory leak in master_fwd_thread.
    
    - If master_fwd_thread is terminated by cygthread::terminate_thread(),
      the opportunity to release tmp_pathbuf is missed, resulting in a
      memory leak. This patch fixes the issue.

Diff:
---
 winsup/cygwin/fhandler_tty.cc | 6 +++++-
 winsup/cygwin/tty.cc          | 1 +
 winsup/cygwin/tty.h           | 1 +
 3 files changed, 7 insertions(+), 1 deletion(-)

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index 16dbc5c0a..f68e80df9 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -2106,7 +2106,9 @@ fhandler_pty_master::close ()
 	      master_ctl = NULL;
 	    }
 	  release_output_mutex ();
-	  master_fwd_thread->terminate_thread ();
+	  get_ttyp ()->stop_fwd_thread = true;
+	  WriteFile (to_master_nat, "", 0, NULL, NULL);
+	  master_fwd_thread->detach ();
 	}
     }
   if (InterlockedDecrement (&master_cnt) == 0)
@@ -2695,6 +2697,8 @@ fhandler_pty_master::pty_master_fwd_thread (const master_fwd_thread_param_t *p)
 	  termios_printf ("ReadFile for forwarding failed, %E");
 	  break;
 	}
+      if (p->ttyp->stop_fwd_thread)
+	break;
       ssize_t wlen = rlen;
       char *ptr = outbuf;
       if (p->ttyp->pcon_activated)
diff --git a/winsup/cygwin/tty.cc b/winsup/cygwin/tty.cc
index e29d73dcb..789528856 100644
--- a/winsup/cygwin/tty.cc
+++ b/winsup/cygwin/tty.cc
@@ -254,6 +254,7 @@ tty::init ()
   last_sig = 0;
   mask_flusho = false;
   discard_input = false;
+  stop_fwd_thread = false;
 }
 
 HANDLE
diff --git a/winsup/cygwin/tty.h b/winsup/cygwin/tty.h
index 25d351a4a..519d7c0d5 100644
--- a/winsup/cygwin/tty.h
+++ b/winsup/cygwin/tty.h
@@ -132,6 +132,7 @@ private:
   xfer_dir pcon_input_state;
   bool mask_flusho;
   bool discard_input;
+  bool stop_fwd_thread;
 
 public:
   HANDLE from_master_nat () const { return _from_master_nat; }