From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS31976 209.132.180.0/23 X-Spam-Status: No, score=-4.0 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_EF,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED,SPF_HELO_PASS,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from sourceware.org (server1.sourceware.org [209.132.180.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dcvr.yhbt.net (Postfix) with ESMTPS id 6433020248 for ; Mon, 11 Mar 2019 12:50:46 +0000 (UTC) DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id :list-unsubscribe:list-subscribe:list-archive:list-post :list-help:sender:from:to:cc:subject:references:date:in-reply-to :message-id:mime-version:content-type:content-transfer-encoding; q=dns; s=default; b=htiK+B0fTZaWi8wfrQFs42cRR2Ye++X/Gl5sXIYFpn4 RIHtMPj6Bj/uLUR3OzqvWzNjB71jlvwa4BRM0D1PBZkpwBbiQIgg2QChqosjzFpB 3nHERSfVgLKEaaiKqM2eZDwnpNKl2yxwQeWafXaXrrBKKEw6G7Mxt7bzZBwruOc4 = 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:from:to:cc:subject:references:date:in-reply-to :message-id:mime-version:content-type:content-transfer-encoding; s=default; bh=lfXlKo5SpV2QhlHdqw/vRcv+Pag=; b=mANjkGQScfngAHKOU 9Mf9Pii0gkJxsU8qLMYxESx0ZsJO/nYj9KJvbHfmSQnsvNuigeZCh38YxKXXATLc UEgdeUNBaWvai2HfJjOSpw9dBy6TfO20CTaGridbs0xhbA1d738NZqptpMPI4uUC YKzYABrpJANCjwqwZ+xNTxP1Pw= Received: (qmail 97918 invoked by alias); 11 Mar 2019 12:50:44 -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: , Sender: libc-alpha-owner@sourceware.org Received: (qmail 97906 invoked by uid 89); 11 Mar 2019 12:50:44 -0000 Authentication-Results: sourceware.org; auth=none X-HELO: mx1.redhat.com From: Florian Weimer To: zhuao Cc: libc-alpha Subject: Re: is there plan to support 'linker namespace' in glib? References: Date: Mon, 11 Mar 2019 13:50:39 +0100 In-Reply-To: (zhuao's message of "Mon, 11 Mar 2019 19:13:06 +0800 (GMT+08:00)") Message-ID: <87d0mx1so0.fsf@oldenburg2.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable * zhuao: > I notice that android bionic support 'linker namespace':=C2=A0https://sou= rce.android.com/devices/architecture/vndk/linker-namespace > it provides additional isolation among software components. > it may also benefit some usage:=C2=A0 > =C2=A0- isolation prebuilt binaries with different toolchain (versioned g= libc) > =C2=A0- it may also give us opportunity to use android binary (HAL) with = glibc, by isolating glib and bionic world in different namespace > > > do you think the above approach is possible? > =C2=A0if yes, is it possible to add such feature to glibc? There have been many discussions over the year. The requirements are quite diverse: some people want group support as in the Solaris linker. Others want dlmopen with a shared malloc (and perhaps shared other libraries; our implementation currently shares only the dynamic linker and nothing else). Again others want to load the same library multiple times, disregarding its soname. Then there is a desire to have some sort of firewall between different linker namespaces, as a general framework, so that you can load the same soname multiple times, and still achieving consistent execution. I think that anything that is fairly general and actually works is still a major research effort, in addition to the work that would be needed to implement it in the current dynamic linker. While a lot of research has been done on modules and how to compose them in the 80s, a lot of that knowledge seems to have been lost or is simply not available to people working on C/C++ implementations today. Thanks, Florian