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 [216.205.24.124]) by sourceware.org (Postfix) with ESMTP id 7FD323857023 for ; Tue, 8 Jun 2021 18:17:25 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 7FD323857023 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-133-OH4YONR9PzSlkRPiX8P9yg-1; Tue, 08 Jun 2021 14:17:23 -0400 X-MC-Unique: OH4YONR9PzSlkRPiX8P9yg-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id B137C1013739; Tue, 8 Jun 2021 18:17:22 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-115-60.ams2.redhat.com [10.36.115.60]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 7BC1A1000324; Tue, 8 Jun 2021 18:17:21 +0000 (UTC) From: Florian Weimer To: "Soni L." Cc: Adhemerval Zanella , Libc-help Subject: Re: inode-based dlopen caching References: <87zgw09tww.fsf@oldenburg.str.redhat.com> <0242da65-0563-d03d-2ba7-5318c2a6c010@linaro.org> <87r1hc9ssx.fsf@oldenburg.str.redhat.com> Date: Tue, 08 Jun 2021 20:17:19 +0200 In-Reply-To: (Soni L.'s message of "Tue, 8 Jun 2021 15:10:02 -0300") Message-ID: <87czsw9q6o.fsf@oldenburg.str.redhat.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain X-Spam-Status: No, score=-6.6 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-help@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-help mailing list List-Unsubscribe: , List-Archive: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 08 Jun 2021 18:17:26 -0000 * Soni L.: > The motivating use-case is hexchat plugins. Especially when they're > written in Rust. Rust is supposed to provide memory safety but some > edge-cases with dlopen break that, like truncating the shared library, > or closing a shared library that has spawned threads. Truncating the shared object will always cause problems until the kernel implements MAP_COPY, or we stop mapping code in the dynamic loader. Another option (implemented by GHC and others) is to have a customer loader. Except for initial-exec memory and symbol interposition, there is nothing magic at all about dlopen. Applications certainly can implement their own object code loading mechanisms. Thanks, Florian