From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by sourceware.org (Postfix) with ESMTPS id 48E713858D28 for ; Thu, 26 Jan 2023 10:43:40 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 48E713858D28 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1674729820; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=9S7QpPGQXRAruasEmT/tRH3NepkBChDfo/xvVpic658=; b=Dav37Q3ojYkKXq8ia2uHnbbER/3uu3wo7pTwtnx8QyFALABEPjQkAzCkunqNPlJAlGk1IC WXHUN7FiYDIM+bM5VYTQQI3Yn0S+MOIi9bend4dI5LZ8TVlZe/IEOMXsRPaOFfFwWES2Mi znrBNynurTq+l5qYci7Vf1UaD1Qy53s= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-374-ecFVXRFXMAexhCYMxyoIJw-1; Thu, 26 Jan 2023 05:43:36 -0500 X-MC-Unique: ecFVXRFXMAexhCYMxyoIJw-1 Received: from smtp.corp.redhat.com (int-mx10.intmail.prod.int.rdu2.redhat.com [10.11.54.10]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 668F1858F09; Thu, 26 Jan 2023 10:43:36 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.39.192.15]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A7A82492B01; Thu, 26 Jan 2023 10:43:35 +0000 (UTC) From: Florian Weimer To: "Andreas K. Huettel via Libc-alpha" Cc: "Andreas K. Huettel" Subject: Re: time64 / Large File Support: 2) default time64 breaks legacy 32bit binaries References: <10857996.18pcnM708K@pinacolada> <7196595.N7aMVyhfb1@pinacolada> Date: Thu, 26 Jan 2023 11:43:34 +0100 In-Reply-To: <7196595.N7aMVyhfb1@pinacolada> (Andreas K. Huettel via Libc-alpha's message of "Thu, 26 Jan 2023 00:59:52 +0100") Message-ID: <87h6wd1sq1.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.10 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Spam-Status: No, score=-4.6 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE,RCVD_IN_MSPIKE_H2,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: * Andreas K. Huettel via Libc-alpha: > This was discussed already in the previous thread on this list [1], > with reactions ranging from "need new triplet" via "need new libdir" > to "meh". The latter is a bit surprising given how much emphasis > glibc usually places on backwards compatibility. > [1] https://sourceware.org/pipermail/libc-alpha/2022-November/143386.html For me, it's =E2=80=9Dmeh=E2=80=9D because for our distributions, we need t= o keep time_t at 32 bits. We don't want to allocate resources to make all core libraries dual-time_t, like it was contributed to glibc. But such a dual-ABI nature would be a prerequisite for offering libraries that support 64-bit time_t. It really has to be in addition to 32-bit time_t. In my world, 32-bit support is for running binaries built with GCC 2.95. (Some of them built decades ago, some of them new.) Fedora also used to have a 32-bit time_t use case for Wine, but I think that is rapidly going away, with Wine transitioning to a different technology for running 32-bit applications (the dependency is purely in the implementation of Wine). I expect that our ABI compatibility requirement will go away in the second half of 2024. Until then, it puts us in conflict with certain 64-bit time_t approaches suggested by the community. I still hope that we can eliminate the requirement sooner, so that I don't have to argue against those approaches, but these kind of decisions are hard. I really wish we could avoid this conflict. > While we could certainly go ahead and invent a solution in Gentoo here, t= his > makes no sense at all for one distribution alone. This is an upstream pro= blem > and should be solved here... pretty please? opinions? There's some risk that several key upstreams will tell us, =E2=80=9Cjust re= build everything with time_t as 64-bit=E2=80=9D, at which point we would have to = come up with a custom, downstream-only ABI that has dual time_t support. And I don't think glibc is the upstream project you need to work with here. Thanks, Florian