Backport some fixes to 3.4

[dscho]

The main reason for this is to verify the proposed fix for #202. While at it, I'll include a couple other fixes for potential hangs.

[dscho]

Here is the range-diff relative to the commits in cygwin-3_5-branch

• 1: aa73e11 ! 1: 621831b Cygwin: console: Fix exit code for non-cygwin process.

  @@ Commit message
       other terminals."), that the pointer cons is accessed before fixing
       when it is NULL. This patch fixes the issue.
   
  +    Backported-from: aa73e11524 (Cygwin: console: Fix exit code for non-cygwin process., 2024-02-02)
       Fixes: 3721a756b0d8 ("Cygwin: console: Make the console accessible from other terminals.")
       Reported-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
       Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
  +    Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
   
    ## winsup/cygwin/fhandler/console.cc ##
   @@ winsup/cygwin/fhandler/console.cc: fhandler_console::need_console_handler ()
    void
    fhandler_console::set_disable_master_thread (bool x, fhandler_console *cons)
    {
  --  const _minor_t unit = cons->get_minor ();
   -  if (con.disable_master_thread == x)
   -    return;
      if (cons == NULL)
  @@ winsup/cygwin/fhandler/console.cc: fhandler_console::set_disable_master_thread (
          else
    	return;
        }
  -+  const _minor_t unit = cons->get_minor ();
   +  if (con.disable_master_thread == x)
   +    return;
      cons->acquire_input_mutex (mutex_timeout);

• 2: 9bcfd06 ! 2: 074a644 Cygwin: console: Avoid slipping past disable_master_thread check.

  @@ Commit message
       processed once after setting disable_master_thread flag. This patch
       prevents that.
   
  +    Backported-from: 9bcfd06045 (Cygwin: console: Avoid slipping past disable_master_thread check., 2024-02-03)
       Fixes: d4aacd50e6cf ("Cygwin: console: Add missing input_mutex guard.")
       Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
  +    Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
   
    ## winsup/cygwin/fhandler/console.cc ##
   @@ winsup/cygwin/fhandler/console.cc: fhandler_console::cons_master_thread (handle_set_t *p, tty *ttyp)
  @@ winsup/cygwin/fhandler/console.cc: fhandler_console::cons_master_thread (handle_
          switch (cygwait (p->input_handle, (DWORD) 0))
    	{
   @@ winsup/cygwin/fhandler/console.cc: fhandler_console::set_disable_master_thread (bool x, fhandler_console *cons)
  +       else
    	return;
        }
  -   const _minor_t unit = cons->get_minor ();
   -  if (con.disable_master_thread == x)
   -    return;
      cons->acquire_input_mutex (mutex_timeout);

• 9: a6ac7b4 ! 3: 4746257 Cygwin: pty: Fix handle leak in master process.

  @@ Commit message
   
       /~https://github.com/msys2/msys2-runtime/issues/198
   
  +    Backported-from: a6ac7b4138 (Cygwin: pty: Fix handle leak in master process., 2024-02-13)
       Fixes: 29431fcb5b14 ("Cygwin: pty: Inherit typeahead data between two input pipes.")
       Reported-by: Hakkin Lain
       Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
  +    Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
   
    ## winsup/cygwin/fhandler/pty.cc ##
   @@ winsup/cygwin/fhandler/pty.cc: fhandler_pty_slave::transfer_input (tty::xfer_dir dir, HANDLE from, tty *ttyp,
  @@ winsup/cygwin/fhandler/pty.cc: fhandler_pty_slave::transfer_input (tty::xfer_dir
    
      /* Fix input_available_event which indicates availability in cyg pipe. */
      if (dir == tty::to_nat) /* all data is transfered to nat pipe,
  -
  - ## winsup/cygwin/release/3.5.1 ##
  -@@ winsup/cygwin/release/3.5.1: Fixes:
  -   error mode is now possible by using the new CYGWIN environment variable
  -   option "winjitdebug".
  -   Addresses: https://cygwin.com/pipermail/cygwin/2024-February/255305.html
  -+
  -+- Fix handle leak in pty master which occurs when non-cygwin process
  -+  is started in pty.
  -+  Addresses: /~https://github.com/msys2/msys2-runtime/issues/198

• 10: 73cd80c ! 4: 8b35e90 Cygwin: pty: Fix potential handle leak regarding CallNamedPipe().

  @@ Commit message
       requests that. Though some of them are not used so should be closed,
       they were not. This causes handle leak potentially.
   
  +    Backported-from: 73cd80c976 (Cygwin: pty: Fix potential handle leak regarding CallNamedPipe()., 2024-02-13)
       Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
  +    Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
   
    ## winsup/cygwin/fhandler/pty.cc ##
   @@ winsup/cygwin/fhandler/pty.cc: fhandler_pty_slave::open (int flags, mode_t)

• 11: 02f7f65 ! 5: 6db75ee Cygwin: console: Make VMIN and VTIME work.

  @@ Commit message
   
       Previously, VMIN and VTIME did not work at all. This patch fixes that.
   
  +    Backported-from: 73cd80c976 (Cygwin: pty: Fix potential handle leak regarding CallNamedPipe()., 2024-02-13)
       Signed-off-by: Takashi Yano <takashi.yano@nifty.ne.jp>
  +    Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
   
    ## winsup/cygwin/fhandler/console.cc ##
   @@ winsup/cygwin/fhandler/console.cc: fhandler_console::read (void *pv, size_t& buflen)
  @@ winsup/cygwin/fhandler/console.cc: wait_retry:
    #undef buf
    
      buflen = copied_chars;
  -
  - ## winsup/cygwin/release/3.5.1 ##
  -@@ winsup/cygwin/release/3.5.1: Fixes:
  - - Fix handle leak in pty master which occurs when non-cygwin process
  -   is started in pty.
  -   Addresses: /~https://github.com/msys2/msys2-runtime/issues/198
  -+
  -+- Fix the problem that VMIN and VTIME does not work at all in console.

• -: ---------- > 6: f30ee6b Cygwin: pipe: Give up to use query_hdl for non-cygwin apps.

[lazka]

Sorry I forgot about this.

lgtm