From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#69083: Emacs's keyboard hook state is not reset on session lock (Windows) Date: Mon, 12 Feb 2024 22:23:54 +0200 Message-ID: <86cyt1qvmt.fsf@gnu.org> References: Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="5123"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 69083@debbugs.gnu.org To: Raffael Stocker Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Mon Feb 12 21:46:10 2024 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1rZdBp-00018O-Rt for geb-bug-gnu-emacs@m.gmane-mx.org; Mon, 12 Feb 2024 21:46:10 +0100 Original-Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rZdBT-0004zR-Eo; Mon, 12 Feb 2024 15:45:47 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rZdBR-0004xo-Is for bug-gnu-emacs@gnu.org; Mon, 12 Feb 2024 15:45:45 -0500 Original-Received: from debbugs.gnu.org ([2001:470:142:5::43]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1rZdBR-0002fk-Aw for bug-gnu-emacs@gnu.org; Mon, 12 Feb 2024 15:45:45 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1rZdBi-0004xa-8H for bug-gnu-emacs@gnu.org; Mon, 12 Feb 2024 15:46:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Mon, 12 Feb 2024 20:46:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 69083 X-GNU-PR-Package: emacs Original-Received: via spool by 69083-submit@debbugs.gnu.org id=B69083.170777074518986 (code B ref 69083); Mon, 12 Feb 2024 20:46:02 +0000 Original-Received: (at 69083) by debbugs.gnu.org; 12 Feb 2024 20:45:45 +0000 Original-Received: from localhost ([127.0.0.1]:57765 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1rZdBQ-0004w7-IB for submit@debbugs.gnu.org; Mon, 12 Feb 2024 15:45:45 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:58636) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1rZdBO-0004vW-7u for 69083@debbugs.gnu.org; Mon, 12 Feb 2024 15:45:43 -0500 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rZcqL-0007ea-Hm; Mon, 12 Feb 2024 15:23:57 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=zxwqDLcxDEsjgYZ8/HwbpyQj1N/pkcH5SrRfTxAbzFg=; b=i5T1AG+ObMdHGbL2hhB4 NQnBjPdkKuG2IEm9rQ6vAw1KGXjrvTj2U7ekF3HUuenNChw34q5pYJS9cLtnfHtyztjTWTVUPJHnM liwt0aHo1WEu7e0D5QS2GzTWQg+WmElpv0FUJd6YRPJUWVA2u+yX+BZxvhDgvZZz9kXC3GJ8unyqi iHI1KEmqfXoEBc+sm8ehJQgrLJn6eNYcXIEWkXq7Y9+rxmLehAG3gVnhEL/wB/kwqTWHJ8LwnKR8o vDYOrG5W+H630NSsaEWc9jmXpGm+Dm5NtZl5IpfBkMYT1HKF9QV2NzzFtFdvlggckqmBdh/xR642r T4n2zjS4lfUrBA==; In-Reply-To: (message from Raffael Stocker on Mon, 12 Feb 2024 20:04:50 +0100) X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Original-Sender: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Xref: news.gmane.io gmane.emacs.bugs:279927 Archived-At: > From: Raffael Stocker > Date: Mon, 12 Feb 2024 20:04:50 +0100 > > when locking the computer using WIN+L on Windows, Emacs is supposed to > reset its keyboard hook state. This is done in the function > ‘reset_w32_kbdhook_state’ in ‘w32fns.c’, which is called upon receiving > the ‘WM_WTSSESSION_CHANGE’ message with the ‘WTS_SESSION_LOCK’ > parameter. However, this message is never received, because to receive > it, an application must register for session notifications, which Emacs > doesn't do. > > When Emacs can't reset its state, the handling of the windows key is > confused after locking and unlocking the computer, but the issue seems > to auto-correct when a windows key is pressed again. I didn't observe > any real problem with it, but I have not configured any non-default > handling of the windows keys in Emacs. It may be different in those > cases. > > Note that while this bug looks like it might be connected to bug#68914, > I believe it's a separate issue. The behaviour described there is > neither triggered by this bug nor solved by the attached patch. > > The attached patch rectifies the situation, but to do so, Emacs must be > linked with ‘wtsapi32.dll’. I am not sure whether there is a different > way of resetting the state that doesn't require the introduction of a > new dependency. We can use that DLL, but we cannot link against it, because that would make the DLL a prerequisite for running Emacs, and then it will be impossible to start Emacs on Windows versions before XP, where that DLL was introduced. So we need to load that DLL at run time via LoadLibrary, and only register for session notifications if the DLL is available, by calling the DLL functions through function pointers -- this way, the Emacs executable doesn't have a static link-time dependency on the DLL. You will find many examples of this technique in w32.c and in other w32*.c files in Emacs. (I'm a bit surprised that Remote Desktop Services need to be used for this purpose. Are you sure there's no other way for Emacs to know that the system is going to be locked? Where did you read about the need to reset the keyboard hook state in that case, and the way to do it?) > To receive session notifications, one must provide a window handle, > which is fine if Emacs does not run in console mode. I don't know > whether it is possible to get these notifications in console Emacs; at > least using the console handle didn't work for me. Please try the technique used by the function find_child_console which is defined in w32proc.c. > I also noticed that while the keyboard hook is set up in console mode > using ‘setup_w32_kbdhook’, there does not seem to be a corresponding > call to ‘remove_w32_kbdhook’. Doesn't Windows remove the hook when the process exits? > Also, in console mode the keyboard hook is always installed, while > in GUI Emacs it is only installed when ‘WINDOWSNT’ is defined. That's because w32console.c is not compiled into the Cygwin build (which does not define WINDOWSNT), whereas w32fns.c is. > @@ -2800,17 +2801,22 @@ setup_w32_kbdhook (void) > /* Set the hook. */ > kbdhook.hook = SetWindowsHookEx (WH_KEYBOARD_LL, funhook, > GetModuleHandle (NULL), 0); > + if (hwnd != NULL) > + WTSRegisterSessionNotificationEx (WTS_CURRENT_SERVER, hwnd, > + NOTIFY_FOR_THIS_SESSION); Do we really need to use WTSRegisterSessionNotificationEx? Can't we use WTSRegisterSessionNotification instead? AFAIK, the latter is available since Windows XP, whereas the former only since Vista. Thanks.