From patchwork Mon Mar 15 10:03:28 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 42538 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 5F5A93858022; Mon, 15 Mar 2021 10:03:32 +0000 (GMT) DKIM-Filter: OpenDKIM Filter v2.11.0 sourceware.org 5F5A93858022 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sourceware.org; s=default; t=1615802612; bh=hByTsQUMhkEAQmHvjWH9Po1JwNjz4S3s8GOxYq2hE9g=; h=To:Subject:Date:List-Id:List-Unsubscribe:List-Archive:List-Post: List-Help:List-Subscribe:From:Reply-To:From; b=kJmDbZVJCTEk7NF3LZLE5iPoJK2Laj4IOiASOFtBi0Jg1NQLCxVneVGIahWXwNNta o0QzuqQEyL4kg1EnLI/7C6lePCrXbrLceorK5JQBfD4jl2o89Ffu752rji0H+CzzG6 CQLxawXn5Yzbct4FuU1wt52OEG1bO6d/CMwid5HM= X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org 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 8DEBC3858C27 for ; Mon, 15 Mar 2021 10:03:29 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 8DEBC3858C27 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-291-CJY7kGJUMTy3tbfcTFF1ZQ-1; Mon, 15 Mar 2021 06:03:24 -0400 X-MC-Unique: CJY7kGJUMTy3tbfcTFF1ZQ-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 8EE26101F001 for ; Mon, 15 Mar 2021 10:03:23 +0000 (UTC) Received: from oldenburg.str.redhat.com (ovpn-112-163.ams2.redhat.com [10.36.112.163]) by smtp.corp.redhat.com (Postfix) with ESMTPS id EA6BE60C5F for ; Mon, 15 Mar 2021 10:03:22 +0000 (UTC) To: libc-alpha@sourceware.org Subject: [PATCH] elf: ld.so --help calls _dl_init_paths without a main map [BZ #27577] Date: Mon, 15 Mar 2021 11:03:28 +0100 Message-ID: <87ft0wybrj.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 X-Spam-Status: No, score=-12.5 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_DNSWL_LOW, RCVD_IN_MSPIKE_H3, 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-Patchwork-Original-From: Florian Weimer via Libc-alpha From: Florian Weimer Reply-To: Florian Weimer Errors-To: libc-alpha-bounces@sourceware.org Sender: "Libc-alpha" In this case, use the link map of the dynamic loader itself as a replacement. This is more than just a hack: if we ever support DT_RUNPATH/DT_RPATH for the dynamic loader, reporting it for ld.so --help (without further command line arguments) would be the right thing to do. Fixes commit 332421312576bd7095e70589154af99b124dd2d1 ("elf: Always set l in _dl_init_paths (bug 23462)"). Tested on i686-linux-gnu and x86_64-linux-gnu. --- elf/Makefile | 10 +++++++++- elf/dl-load.c | 8 +++++++- 2 files changed, 16 insertions(+), 2 deletions(-) diff --git a/elf/Makefile b/elf/Makefile index 4c9e63dac9..ebb331df36 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -245,7 +245,8 @@ tests += $(tests-execstack-$(have-z-execstack)) ifeq ($(run-built-tests),yes) tests-special += $(objpfx)tst-leaks1-mem.out \ $(objpfx)tst-leaks1-static-mem.out $(objpfx)noload-mem.out \ - $(objpfx)tst-ldconfig-X.out + $(objpfx)tst-ldconfig-X.out $(objpfx)tst-rtld-help.out \ + $(objpfx)tst-rtld-help-2.out endif tlsmod17a-suffixes = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 tlsmod18a-suffixes = 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 @@ -1907,3 +1908,10 @@ $(objpfx)list-tunables.out: tst-rtld-list-tunables.sh $(objpfx)ld.so $(evaluate-test) tst-dst-static-ENV = LD_LIBRARY_PATH='$$ORIGIN' + +$(objpfx)tst-rtld-help.out: $(objpfx)ld.so + $(test-wrapper) $(rtld-prefix) --help > $@; \ + $(evaluate-test) +$(objpfx)tst-rtld-help-2.out: $(objpfx)tst-rtld-help.out + grep -q 'Legacy HWCAP subdirectories under library search path directories' $<; \ + $(evaluate-test) diff --git a/elf/dl-load.c b/elf/dl-load.c index 376a2e64d6..2f760503c5 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -758,8 +758,14 @@ _dl_init_paths (const char *llp, const char *source, max_dirnamelen = SYSTEM_DIRS_MAX_LEN; *aelem = NULL; - /* This points to the map of the main object. */ + /* This points to the map of the main object. If there is no main + object (e.g., under --help, use the dynamic loader itself as a + stand-in. */ l = GL(dl_ns)[LM_ID_BASE]._ns_loaded; +#ifdef SHARED + if (l == NULL) + l = &GL (dl_rtld_map); +#endif assert (l->l_type != lt_loaded); if (l->l_info[DT_RUNPATH])