From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Paul Eggert Newsgroups: gmane.emacs.devel Subject: Re: Using the GNU GMP Library for Bignums in Emacs Date: Sat, 21 Apr 2018 11:37:43 -0700 Organization: UCLA Computer Science Department Message-ID: <55776605-8940-0a4a-34fb-f3d1b955ab12@cs.ucla.edu> References: <29f933ac-a6bf-8742-66a7-0a9d6d3e5a88@disroot.org> <87k1t05wz4.fsf@metalevel.at> NNTP-Posting-Host: blaine.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: quoted-printable X-Trace: blaine.gmane.org 1524335788 554 195.159.176.226 (21 Apr 2018 18:36:28 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Sat, 21 Apr 2018 18:36:28 +0000 (UTC) User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 To: Markus Triska , emacs-devel@gnu.org Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Sat Apr 21 20:36:24 2018 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1f9xN2-0008Uv-1l for ged-emacs-devel@m.gmane.org; Sat, 21 Apr 2018 20:36:24 +0200 Original-Received: from localhost ([::1]:36754 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f9xP8-0001sp-H8 for ged-emacs-devel@m.gmane.org; Sat, 21 Apr 2018 14:38:34 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:43019) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1f9xOT-0001sN-Hn for emacs-devel@gnu.org; Sat, 21 Apr 2018 14:37:54 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1f9xOQ-00043I-Ff for emacs-devel@gnu.org; Sat, 21 Apr 2018 14:37:53 -0400 Original-Received: from zimbra.cs.ucla.edu ([131.179.128.68]:35996) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1f9xOQ-0003zM-8P for emacs-devel@gnu.org; Sat, 21 Apr 2018 14:37:50 -0400 Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id 8248516005C; Sat, 21 Apr 2018 11:37:48 -0700 (PDT) Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10032) with ESMTP id Gq9NCBDPy5VF; Sat, 21 Apr 2018 11:37:47 -0700 (PDT) Original-Received: from localhost (localhost [127.0.0.1]) by zimbra.cs.ucla.edu (Postfix) with ESMTP id A88D8160860; Sat, 21 Apr 2018 11:37:47 -0700 (PDT) X-Virus-Scanned: amavisd-new at zimbra.cs.ucla.edu Original-Received: from zimbra.cs.ucla.edu ([127.0.0.1]) by localhost (zimbra.cs.ucla.edu [127.0.0.1]) (amavisd-new, port 10026) with ESMTP id DqQSEwJBrMkO; Sat, 21 Apr 2018 11:37:46 -0700 (PDT) Original-Received: from [192.168.1.9] (unknown [47.154.30.119]) by zimbra.cs.ucla.edu (Postfix) with ESMTPSA id A6D8C16005C; Sat, 21 Apr 2018 11:37:46 -0700 (PDT) In-Reply-To: <87k1t05wz4.fsf@metalevel.at> Content-Language: en-US X-detected-operating-system: by eggs.gnu.org: GNU/Linux 3.x [fuzzy] X-Received-From: 131.179.128.68 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: "Emacs-devel" Xref: news.gmane.org gmane.emacs.devel:224773 Archived-At: Markus Triska wrote: > Using GMP has a significant downside if you run out of memory: There=E2= =80=99s > currently no defined way for the allocation functions to recover from a= n > error such as out of memory, they must *terminate* program execution. This should not be a problem if we use GMP's mpn_* functions. They never=20 allocate memory; it is the user's responsibility to allocate it. This sho= uld fit=20 better with how Emacs does things internally. > Also, it may become hard to stop long GMP calculations, whereas you can > easily stop computations that are written in Elisp. Thus, long GMP > calculations may lead to denial of editing attacks. Yes, this could be a problem. Perhaps we'll need to extend GMP to fix it.= On the=20 other hand, no doubt there are other, similar problems in GNU Emacs (just= look=20 for calls to memcpy :-), and perhaps this problem could just be added to = the list.