[PATCH v2] Cygwin: pty: Add missing CloseHandle() calls.

[Takashi Yano]

- PTY code which support pseudo console has a problem that causes
  handle leaks. Four of these are bug in pty code, and the other
  one seems to be a bug of Windows10. ClosePseudoConsole() fails
  to close one internal handle. This patch fixes the issue.
---
 winsup/cygwin/fhandler_tty.cc | 16 ++++++++++++++--
 winsup/cygwin/ntdll.h         | 13 +++++++++++++
 2 files changed, 27 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/fhandler_tty.cc b/winsup/cygwin/fhandler_tty.cc
index ca4dc1c20..1a3bdc5ea 100644
--- a/winsup/cygwin/fhandler_tty.cc
+++ b/winsup/cygwin/fhandler_tty.cc
@@ -2224,11 +2224,21 @@ fhandler_pty_master::close ()
 	  /* Terminate helper process */
 	  SetEvent (get_ttyp ()->h_helper_goodbye);
 	  WaitForSingleObject (get_ttyp ()->h_helper_process, INFINITE);
+	  CloseHandle (get_ttyp ()->h_helper_goodbye);
+	  CloseHandle (get_ttyp ()->h_helper_process);
 	  /* FIXME: Pseudo console can be accessed via its handle
 	     only in the process which created it. What else can we do? */
 	  if (master_pid_tmp == myself->pid)
-	    /* Release pseudo console */
-	    ClosePseudoConsole (get_pseudo_console ());
+	    {
+	      /* ClosePseudoConsole() seems to have a bug that one
+		 internal handle remains opened. This causes handle leak.
+		 This is a workaround for this problem. */
+	      HPCON_INTERNAL *hp = (HPCON_INTERNAL *) get_pseudo_console ();
+	      HANDLE tmp = hp->hConHostProcess;
+	      /* Release pseudo console */
+	      ClosePseudoConsole (get_pseudo_console ());
+	      CloseHandle (tmp);
+	    }
 	  get_ttyp ()->switch_to_pcon_in = false;
 	  get_ttyp ()->switch_to_pcon_out = false;
 	}
@@ -3191,6 +3201,8 @@ fhandler_pty_master::setup_pseudoconsole ()
 		  TRUE, EXTENDED_STARTUPINFO_PRESENT,
 		  NULL, NULL, &si_helper.StartupInfo, &pi_helper);
   WaitForSingleObject (hello, INFINITE);
+  CloseHandle (hello);
+  CloseHandle (pi_helper.hThread);
   /* Retrieve pseudo console handles */
   DWORD rLen;
   char buf[64];
diff --git a/winsup/cygwin/ntdll.h b/winsup/cygwin/ntdll.h
index 1c07d0255..8a08111db 100644
--- a/winsup/cygwin/ntdll.h
+++ b/winsup/cygwin/ntdll.h
@@ -1763,4 +1763,17 @@ extern "C"
     return status;
   }
 }
+
+/* This is for pseudo console workaround. ClosePseudoConsole()
+   seems to have a bug that one internal handle remains opend.
+   This causes handle leak. To close this handle, it is needed
+   to access internal of HPCON. HPCON_INTERNAL is defined for
+   this purpose. The structure of internal of HPCON is not
+   documented. Refer to: https://github.com/Biswa96/XConPty */
+typedef struct _HPCON_INTERNAL
+{
+  HANDLE hWritePipe;
+  HANDLE hConDrvReference;
+  HANDLE hConHostProcess;
+} HPCON_INTERNAL;
 #endif
-- 
2.21.0