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 ESMTP id 880D43857836 for ; Wed, 7 Apr 2021 18:41:23 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 880D43857836 Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-186-sEQbNLNRN8i6rPah_WtoLA-1; Wed, 07 Apr 2021 14:41:20 -0400 X-MC-Unique: sEQbNLNRN8i6rPah_WtoLA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id DF7F710054F6; Wed, 7 Apr 2021 18:41:18 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-12.rdu2.redhat.com [10.10.112.12]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 10E6F610A8; Wed, 7 Apr 2021 18:41:16 +0000 (UTC) From: Florian Weimer To: Adhemerval Zanella Cc: Michal Nazarewicz , libc-alpha@sourceware.org, carlos@systemhalted.org Subject: Re: [PATCH] linux: sysconf: limit _SC_MAX_ARG to 6 MiB [BZ #25305] References: <20210407151058.1176364-1-mina86@mina86.com> <6c926d3b-3094-f220-7777-91dacf975275@linaro.org> Date: Wed, 07 Apr 2021 20:41:31 +0200 In-Reply-To: <6c926d3b-3094-f220-7777-91dacf975275@linaro.org> (Adhemerval Zanella's message of "Wed, 7 Apr 2021 15:36:48 -0300") Message-ID: <878s5u7x9g.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.4 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H4, RCVD_IN_MSPIKE_WL, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 07 Apr 2021 18:41:24 -0000 * Adhemerval Zanella: > It is unfortunate that Linux did not provide a dynamic way to obtain > this value, specially since it has changed over versions. So we will > need to continue using heuristics. We can do a binary search using a test binary, perhaps the dynamic linker itself. We can probe a few known values first to speed things up, I guess. It's hideous, but given that the kernel doesn't support us here, what else can we do? Thanks, Florian