From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Florian Weimer Newsgroups: gmane.comp.lib.glibc.alpha,gmane.emacs.devel Subject: Re: Removal of unexec support from glibc malloc Date: Tue, 19 Jan 2016 00:16:36 +0100 Message-ID: <569D7254.5070406@redhat.com> References: <569CDB81.6040600@redhat.com> <569D3BE0.6050103@cs.ucla.edu> <569D4157.7050408@dancol.org> <569D432F.9070308@dancol.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit X-Trace: ger.gmane.org 1453159014 8946 80.91.229.3 (18 Jan 2016 23:16:54 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Mon, 18 Jan 2016 23:16:54 +0000 (UTC) Cc: Daniel Colascione , Zack Weinberg , emacs-devel@gnu.org, GNU C Library To: Joseph Myers Original-X-From: libc-alpha-return-66388-glibc-alpha=m.gmane.org@sourceware.org Tue Jan 19 00:16:52 2016 Return-path: Envelope-to: glibc-alpha@plane.gmane.org Original-Received: from server1.sourceware.org ([209.132.180.131] helo=sourceware.org) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1aLJ2Z-0004Ox-DP for glibc-alpha@plane.gmane.org; Tue, 19 Jan 2016 00:16:51 +0100 DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:subject:to:references:cc:from:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; q=dns; s=default; b=eHWME1v7u2Xy7g/D 9Pb9p0nYfY5SubGvkFsaBTfUv8sRQp5IY1NoJu/97wCaTYntLEsnEvr7bI/oP4M3 cFEHdt9sOGO5/50OKjW5Bkyy2yRhaa1S3Eplum1ewZgzUL3OrPU7RBU4Zy8QHTfq sq+ZzSr3TdxOs277rCaeEfkR8I8= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:subject:to:references:cc:from:message-id:date :mime-version:in-reply-to:content-type :content-transfer-encoding; s=default; bh=XwVRYdQN5MDWvXcqS4ptYQ w7U9U=; b=Fll33fZI5CQf7lihZyEQy8ZS6HVDDVM4d2ChfHQSX8v3h/H5vxhZHI iRQkuACX+KDuYMJz9cHWgPkhZ5xL3SrCCuNEQO8zLjiIv9Ha1Qe5aVvFMvAlFYtF 6kKDDb/XwjjyDD8wdwtL3WOKIaaUOcJWn39xAyVaADFUSTm8GIG4M= Original-Received: (qmail 50046 invoked by alias); 18 Jan 2016 23:16:42 -0000 Mailing-List: contact libc-alpha-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Unsubscribe: List-Subscribe: List-Archive: List-Post: List-Help: , Original-Sender: libc-alpha-owner@sourceware.org Original-Received: (qmail 50029 invoked by uid 89); 18 Jan 2016 23:16:41 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-1.9 required=5.0 tests=BAYES_00,RP_MATCHES_RCVD,SPF_HELO_PASS autolearn=ham version=3.3.2 spammy=Being, cooperate X-HELO: mx1.redhat.com User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.4.0 In-Reply-To: Xref: news.gmane.org gmane.comp.lib.glibc.alpha:58671 gmane.emacs.devel:198314 Archived-At: On 01/18/2016 11:27 PM, Joseph Myers wrote: > On Mon, 18 Jan 2016, Daniel Colascione wrote: > >> On 01/18/2016 11:54 AM, Zack Weinberg wrote: >>> On Mon, Jan 18, 2016 at 2:47 PM, Daniel Colascione wrote: >>>> >>>> As long as the ABI support is there, we can keep using the "separate >>>> malloc implementation" even if glibc doesn't cooperate by providing >>>> convenient headers to access it. >>> >>> Clarification: it will not be possible to link new executables against >>> the symbols in question. (This is what a "compat symbol" in glibc is - >>> available only to existing binaries, not to new invocations of ld.) >> >> Oh, with a linker script or other hackery, I'm sure I could make it >> available to new invocations of ld. It's just bytes. > > Being a compat symbol also means that future architecture ports and ABIs > don't include the functionality at all. And even if the symbol is still there, the the version you need to supply will be architecture-specific. Don't do this. :) Florian