[PATCH] Cygwin: pty: Fix potential handle leak regarding CallNamedPipe().

[Takashi Yano]

In pty master_thread, 6 handles are duplicated when CallNamedPipe()
requests that. Though some of them are not used so should be closed,
they were not. This causes handle leak potentially.

Signed-off-by: Takashi Yano <takashi.y...@nifty.ne.jp>
---
 winsup/cygwin/fhandler/pty.cc | 20 ++++++++++++++++++--
 1 file changed, 18 insertions(+), 2 deletions(-)

diff --git a/winsup/cygwin/fhandler/pty.cc b/winsup/cygwin/fhandler/pty.cc
index c5c792144..d31d30b1f 100644
--- a/winsup/cygwin/fhandler/pty.cc
+++ b/winsup/cygwin/fhandler/pty.cc
@@ -936,6 +936,8 @@ fhandler_pty_slave::open (int flags, mode_t)
          errmsg = "can't call master, %E";
          goto err;
        }
+      CloseHandle (repl.to_slave_nat); /* not used. */
+      CloseHandle (repl.to_slave); /* not used. */
       from_master_nat_local = repl.from_master_nat;
       from_master_local = repl.from_master;
       to_master_nat_local = repl.to_master_nat;
@@ -1210,6 +1212,10 @@ fhandler_pty_slave::reset_switch_to_nat_pipe (void)
                      if (!CallNamedPipe (pipe, &req, sizeof req,
                                          &repl, sizeof repl, &len, 500))
                        return; /* What can we do? */
+                     CloseHandle (repl.from_master); /* not used. */
+                     CloseHandle (repl.to_master); /* not used. */
+                     CloseHandle (repl.to_slave_nat); /* not used. */
+                     CloseHandle (repl.to_slave); /* not used. */
                      CloseHandle (get_handle_nat ());
                      set_handle_nat (repl.from_master_nat);
                      CloseHandle (get_output_handle_nat ());
@@ -3861,10 +3867,20 @@ fhandler_pty_slave::transfer_input (tty::xfer_dir dir, 
HANDLE from, tty *ttyp,
       if (!CallNamedPipe (pipe, &req, sizeof req,
                          &repl, sizeof repl, &len, 500))
        return; /* What can we do? */
+      CloseHandle (repl.from_master_nat); /* not used. */
+      CloseHandle (repl.from_master); /* not used. */
+      CloseHandle (repl.to_master_nat); /* not used. */
+      CloseHandle (repl.to_master); /* not used. */
       if (dir == tty::to_nat)
-       to = repl.to_slave_nat;
+       {
+         CloseHandle (repl.to_slave); /* not used. */
+         to = repl.to_slave_nat;
+       }
       else
-       to = repl.to_slave;
+       {
+         CloseHandle (repl.to_slave_nat); /* not used. */
+         to = repl.to_slave;
+       }
     }
 
   UINT cp_from = 0, cp_to = 0;
-- 
2.43.0