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#49261: 28.0.50; File Locking Breaks Presumptuous Toolchains Date: Wed, 07 Jul 2021 21:33:48 +0300 Message-ID: <8335sqezxv.fsf@gnu.org> References: <87o8bn7bie.fsf@gnus.org> <87zgv6vuon.fsf@gmx.de> <837di9lwbm.fsf@gnu.org> <87a6n5vuu4.fsf@gnus.org> <8735sqnmei.fsf@gnus.org> <87zguyf4ht.fsf@gmx.de> <87pmvum54p.fsf@gnus.org> <87v95mf2lj.fsf@gmx.de> <87lf6im1xr.fsf@gnus.org> Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="19181"; mail-complaints-to="usenet@ciao.gmane.io" Cc: michael.albinus@gmx.de, ncaprisunfan@gmail.com, 49261@debbugs.gnu.org To: Lars Ingebrigtsen Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Wed Jul 07 20:34:21 2021 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 1m1CNJ-0004iI-ED for geb-bug-gnu-emacs@m.gmane-mx.org; 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Wed, 07 Jul 2021 18:34:02 +0000 Original-Received: (at 49261) by debbugs.gnu.org; 7 Jul 2021 18:33:55 +0000 Original-Received: from localhost ([127.0.0.1]:53442 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1m1CMt-0006sn-FI for submit@debbugs.gnu.org; Wed, 07 Jul 2021 14:33:55 -0400 Original-Received: from eggs.gnu.org ([209.51.188.92]:34922) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1m1CMo-0006sX-IY for 49261@debbugs.gnu.org; Wed, 07 Jul 2021 14:33:53 -0400 Original-Received: from fencepost.gnu.org ([2001:470:142:3::e]:41566) by eggs.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m1CMf-0007Lv-S7; Wed, 07 Jul 2021 14:33:43 -0400 Original-Received: from 84.94.185.95.cable.012.net.il ([84.94.185.95]:2814 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m1CMf-0007Vg-4m; Wed, 07 Jul 2021 14:33:41 -0400 In-Reply-To: <87lf6im1xr.fsf@gnus.org> (message from Lars Ingebrigtsen on Wed, 07 Jul 2021 20:08:48 +0200) 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" Xref: news.gmane.io gmane.emacs.bugs:209610 Archived-At: > From: Lars Ingebrigtsen > Cc: Eli Zaretskii , ncaprisunfan@gmail.com, > 49261@debbugs.gnu.org > Date: Wed, 07 Jul 2021 20:08:48 +0200 > > While looking at this code, I'm puzzled by: > > - orig_fn = fn; > - fn = Fexpand_file_name (fn, Qnil); > -#ifdef WINDOWSNT > - /* Ensure we have only '/' separators, to avoid problems with > - looking (inside fill_in_lock_file_name) for backslashes in file > - names encoded by some DBCS codepage. */ > - dostounix_filename (SSDATA (fn)); > -#endif > - encoded_fn = ENCODE_FILE (fn); > - if (create_lockfiles) > - /* Create the name of the lock-file for file fn */ > - MAKE_LOCK_NAME (lfname, encoded_fn); > - > > So here we (possibly destructively) alter the data in the fn string on > WINDOWSNT, because we want to avoid problems in fill_in_lock_file_name. > OK, but we call MAKE_LOCK_NAME (which calls fill_in_lock_file_name) in > two other places, and in those places the call isn't guarded by a call > to dostounix_filename. > > This is moot after my patch, since MAKE_LOCK_NAME is gone, but I'm still > worried that there's something I don't understand here... The > dostounix_filename call was added by Eli in 2013. It's a bug. Or maybe it was a bug, back then, because I think nowadays expand-file-name always converts backslashes to forward slashes. And actually the fact that MAKE_LOCK_NAME looks for slashes in encoded file names is also a subtle bug (or at least unsafe code): some coding-systems don't guarantee that a '/' byte can never be part of a multibyte sequence.