From patchwork Thu Jul 8 16:32:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Vivek Dasmohapatra X-Patchwork-Id: 44256 Return-Path: X-Original-To: patchwork@sourceware.org Delivered-To: patchwork@sourceware.org Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 358873943404 for ; Thu, 8 Jul 2021 16:35:42 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 358873943404 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1625762142; bh=aOUzPVGzNnCTcEzN/+stzKQCctDin0F+sJ9LosktBYo=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=GcquHKASLzpp8dmNL1ukBzv2qH/Axoq/9yv1w9b4DnyzkodPm4WVEG2Z/GOYICmEX ruQKROlntDLfWSyUF1zfUfp57vSCCMNC7aZO2NbTw10ck33uo3C/WoXQqpSp8HwHxz gj8wqpJq8HV8UTM8R2B4LkcvvhMBVUkhs34faBUs= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [IPv6:2a00:1098:0:82:1000:25:2eeb:e3e3]) by sourceware.org (Postfix) with ESMTPS id 07C533939C2E for ; Thu, 8 Jul 2021 16:33:04 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.1 sourceware.org 07C533939C2E Received: from noise.cbg.collabora.co.uk (unknown [IPv6:2001:4d48:ad5c:ef00:8e70:5aff:fe59:c29c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) (Authenticated sender: vivek) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 11A8D1F43DC9 for ; Thu, 8 Jul 2021 17:33:03 +0100 (BST) To: libc-alpha@sourceware.org Subject: [RFC][PATCH v12 0/8] Implementation of RTLD_SHARED for dlmopen Date: Thu, 8 Jul 2021 17:32:47 +0100 Message-Id: <20210708163255.812-1-vivek@collabora.com> X-Mailer: git-send-email 2.20.1 MIME-Version: 1.0 X-Spam-Status: No, score=-6.5 required=5.0 tests=BAYES_00, KAM_ASCII_DIVIDERS, KAM_DMARC_STATUS, SPF_HELO_PASS, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.4 X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) 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-Patchwork-Original-From: =?utf-8?q?Vivek_Das=C2=A0Mohapatra_via_Libc-alpha?= From: Vivek Dasmohapatra Reply-To: =?utf-8?q?Vivek_Das=C2=A0Mohapatra?= Errors-To: libc-alpha-bounces+patchwork=sourceware.org@sourceware.org Sender: "Libc-alpha" This is a revision of a previous patchset that I posted here regarding https://sourceware.org/bugzilla/show_bug.cgi?id=22745 Introduction: ======================================================================= As discussed in the URL above dlmopen requires a mechanism for [optionally] sharing some objects between more than one namespace. The following patchset provides an implementation for this: If an object is loaded with the new RTLD_SHARED flag we instead ensure that a "master" copy exists (and is flagged as no-delete) in the main namespace and a thin wrapper or clone is placed in the target namespace. This patch series should address all the comments received on the earlier (v1-v10) series. ======================================================================= Changes from v11: - If a DSO is required in a non-base namespace because it is mentioned in a DT_NEEDED entry and it is itself flagged DF_GNU_1_UNIQUE then a proxy is generated for it. - Relocations via non-base namespace proxies work reliably (some code paths did not do the address calculation relative to the DSO base correctly when a proxy was involved). - Tests extended cover the above two scenarios. Changes from v10: - A segfault in a dlmopen error pathway (which does not seem to have existed when v10 was applied to the then-HEAD commit) has been fixed. - The fallback mechanism for adding DT_GNU_FLAGS_1 sections to the required binaries has had some infrastructure moved to the elf/ directory - The runstatedir setting introduced by recent autoconf has been omitted from the patchset as it is not relevant to this feature. - libpthread no longer tagged DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE. (with both -z unique supporting linkers and if the .os hack is used to add the new flag - this was inconsistent before). Not changed: - There is still some diagnostic info in the config.log when the linker layout is acceptable but -z unique is not yet supported. I believe this _is_ useful diagnostic information as a developer might otherwise wonder why the vanilla linker was being rejected when its layout output seemed fine. I have not yet implemented, but plan to address once this series is accepted/acceptable: - dl_iterate_ns_phdr (cf dl_iterate_phdr but taking a namespace argument) - Check RTLD_GLOBAL interacts properly and unsurprisingly with RTLD_SHARED. Vivek Das Mohapatra (8): Define a new dynamic section tag - DT_GNU_FLAGS_1 (bug 22745) Abstract loaded-DSO search code into a helper function Use the new DSO finder helper function Add DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE to glibc DSOs (bug 22745) Implement dlmopen RTLD_SHARED flag (bug 22745) Add dlmopen / RTLD_SHARED tests Restore separate libc loading for the TLS/namespace storage test Drop DT_GNU_FLAGS_1/DF_GNU_1_UNIQUE from the libpthread DSO Makeconfig | 3 + Makerules | 18 +- bits/dlfcn.h | 10 + config.make.in | 1 + configure | 42 +- configure.ac | 31 +- elf/Makefile | 109 +++- elf/dl-close.c | 43 +- elf/dl-deps.c | 17 + elf/dl-fini.c | 6 +- elf/dl-init.c | 4 +- elf/dl-load.c | 223 ++++++- elf/dl-lookup.c | 26 +- elf/dl-object.c | 78 +++ elf/dl-open.c | 121 +++- elf/dl-sym.c | 14 + elf/dynamic-notes.c | 4 + elf/elf.h | 7 +- elf/get-dynamic-info.h | 12 + elf/rtld.c | 2 +- elf/tst-dlmopen-auditmod.c | 23 + elf/tst-dlmopen-common.h | 33 + elf/tst-dlmopen-main.h | 879 +++++++++++++++++++++++++++ elf/tst-dlmopen-modules.h | 21 + elf/tst-dlmopen-rtld-audit-shared1.c | 8 + elf/tst-dlmopen-rtld-audit-shared2.c | 8 + elf/tst-dlmopen-rtld-audit-shared3.c | 7 + elf/tst-dlmopen-rtld-audit-shared4.c | 8 + elf/tst-dlmopen-rtld-audit-shared5.c | 8 + elf/tst-dlmopen-rtld-audit-shared6.c | 8 + elf/tst-dlmopen-rtld-audit-unique1.c | 7 + elf/tst-dlmopen-rtld-audit-unique2.c | 7 + elf/tst-dlmopen-rtld-audit-unique3.c | 7 + elf/tst-dlmopen-rtld-audit-unique4.c | 7 + elf/tst-dlmopen-rtld-audit-unique5.c | 7 + elf/tst-dlmopen-rtld-audit-unique6.c | 7 + elf/tst-dlmopen-rtld-shared1.c | 7 + elf/tst-dlmopen-rtld-shared1.h | 64 ++ elf/tst-dlmopen-rtld-shared2.c | 7 + elf/tst-dlmopen-rtld-shared2.h | 66 ++ elf/tst-dlmopen-rtld-shared3.c | 7 + elf/tst-dlmopen-rtld-shared3.h | 43 ++ elf/tst-dlmopen-rtld-shared4.c | 7 + elf/tst-dlmopen-rtld-shared4.h | 14 + elf/tst-dlmopen-rtld-shared5.c | 7 + elf/tst-dlmopen-rtld-shared5.h | 25 + elf/tst-dlmopen-rtld-shared6.c | 7 + elf/tst-dlmopen-rtld-shared6.h | 36 ++ elf/tst-dlmopen-rtld-unique1.c | 7 + elf/tst-dlmopen-rtld-unique1.h | 86 +++ elf/tst-dlmopen-rtld-unique2.c | 7 + elf/tst-dlmopen-rtld-unique2.h | 25 + elf/tst-dlmopen-rtld-unique3.c | 7 + elf/tst-dlmopen-rtld-unique3.h | 13 + elf/tst-dlmopen-rtld-unique4.c | 7 + elf/tst-dlmopen-rtld-unique4.h | 14 + elf/tst-dlmopen-rtld-unique5.c | 7 + elf/tst-dlmopen-rtld-unique5.h | 58 ++ elf/tst-dlmopen-rtld-unique6.c | 7 + elf/tst-dlmopen-rtld-unique6.h | 51 ++ elf/tst-dlmopen-sharedmod-norm.c | 34 ++ elf/tst-dlmopen-sharedmod-uniq.c | 33 + elf/tst-dlmopen-std-do-test.c | 12 + elf/tst-tls-ie-dlmopen.c | 4 +- extra-lib.mk | 5 + htl/Makefile | 4 + iconvdata/Makefile | 3 + iconvdata/extra-module.mk | 4 + include/elf.h | 2 + include/link.h | 7 +- nptl/Makefile | 8 +- sysdeps/generic/ldsodefs.h | 11 + sysdeps/mips/bits/dlfcn.h | 10 + 73 files changed, 2455 insertions(+), 77 deletions(-) create mode 100644 elf/dynamic-notes.c create mode 100644 elf/tst-dlmopen-auditmod.c create mode 100644 elf/tst-dlmopen-common.h create mode 100644 elf/tst-dlmopen-main.h create mode 100644 elf/tst-dlmopen-modules.h create mode 100644 elf/tst-dlmopen-rtld-audit-shared1.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared2.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared3.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared4.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared5.c create mode 100644 elf/tst-dlmopen-rtld-audit-shared6.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique1.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique2.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique3.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique4.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique5.c create mode 100644 elf/tst-dlmopen-rtld-audit-unique6.c create mode 100644 elf/tst-dlmopen-rtld-shared1.c create mode 100644 elf/tst-dlmopen-rtld-shared1.h create mode 100644 elf/tst-dlmopen-rtld-shared2.c create mode 100644 elf/tst-dlmopen-rtld-shared2.h create mode 100644 elf/tst-dlmopen-rtld-shared3.c create mode 100644 elf/tst-dlmopen-rtld-shared3.h create mode 100644 elf/tst-dlmopen-rtld-shared4.c create mode 100644 elf/tst-dlmopen-rtld-shared4.h create mode 100644 elf/tst-dlmopen-rtld-shared5.c create mode 100644 elf/tst-dlmopen-rtld-shared5.h create mode 100644 elf/tst-dlmopen-rtld-shared6.c create mode 100644 elf/tst-dlmopen-rtld-shared6.h create mode 100644 elf/tst-dlmopen-rtld-unique1.c create mode 100644 elf/tst-dlmopen-rtld-unique1.h create mode 100644 elf/tst-dlmopen-rtld-unique2.c create mode 100644 elf/tst-dlmopen-rtld-unique2.h create mode 100644 elf/tst-dlmopen-rtld-unique3.c create mode 100644 elf/tst-dlmopen-rtld-unique3.h create mode 100644 elf/tst-dlmopen-rtld-unique4.c create mode 100644 elf/tst-dlmopen-rtld-unique4.h create mode 100644 elf/tst-dlmopen-rtld-unique5.c create mode 100644 elf/tst-dlmopen-rtld-unique5.h create mode 100644 elf/tst-dlmopen-rtld-unique6.c create mode 100644 elf/tst-dlmopen-rtld-unique6.h create mode 100644 elf/tst-dlmopen-sharedmod-norm.c create mode 100644 elf/tst-dlmopen-sharedmod-uniq.c create mode 100644 elf/tst-dlmopen-std-do-test.c