From patchwork Sun Sep 29 16:34:47 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Florian Weimer X-Patchwork-Id: 1990618 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@legolas.ozlabs.org Authentication-Results: legolas.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=DNSrUbc2; dkim-atps=neutral Authentication-Results: legolas.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=sourceware.org (client-ip=2620:52:3:1:0:246e:9693:128c; helo=server2.sourceware.org; envelope-from=libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org; receiver=patchwork.ozlabs.org) Received: from server2.sourceware.org (server2.sourceware.org [IPv6:2620:52:3:1:0:246e:9693:128c]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (secp384r1) server-digest SHA384) (No client certificate requested) by legolas.ozlabs.org (Postfix) with ESMTPS id 4XGqZx2t0rz1xt9 for ; Mon, 30 Sep 2024 02:36:09 +1000 (AEST) Received: from server2.sourceware.org (localhost [IPv6:::1]) by sourceware.org (Postfix) with ESMTP id 33730385E45C for ; Sun, 29 Sep 2024 16:36:07 +0000 (GMT) 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 [170.10.133.124]) by sourceware.org (Postfix) with ESMTP id 01BC8385EC29 for ; Sun, 29 Sep 2024 16:34:53 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.4.2 sourceware.org 01BC8385EC29 Authentication-Results: sourceware.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: sourceware.org; spf=pass smtp.mailfrom=redhat.com ARC-Filter: OpenARC Filter v1.0.0 sourceware.org 01BC8385EC29 Authentication-Results: server2.sourceware.org; arc=none smtp.remote-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1727627698; cv=none; b=sBFiMW8KvSUc0A+o4nYjys+vj/Ngcf6MjnrpJ4qUMZOBuNNRq3y4myzJP3k+qdSVv3sMWaV559wip+SrDjPlEkShNev4rZLa58Po8gapXwPifx5IH5IHPCVkUgJ6rgwJaocgxLNsIMJWF53yLJHrKEmBsbXEGoOVtRv4XnIpFxg= ARC-Message-Signature: i=1; a=rsa-sha256; d=sourceware.org; s=key; t=1727627698; c=relaxed/simple; bh=73Vl9uW3GnZ2CZGcHAptm6ArgGySjpp+KjxghOtCMmI=; h=DKIM-Signature:From:To:Subject:Message-ID:Date:MIME-Version; b=oH13ySt4lg74ZwNbHWxmT5hwdMaWK2hRHqj/NleESXViT7+7S1BcDZs2q7CuWc4N6xB2G7kF+lYj8vlxUcqv6YEmMmUCecIKH6cfrxg33COMHlsWnyEli0WHm7JG8gitk1CXQP0Ts90GPOx6F58Dvv3VgChXRVsViHbkmlZ7Fsw= ARC-Authentication-Results: i=1; server2.sourceware.org DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1727627693; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=S7VQElD9KlvOJTO81HseF0KP6oD5f6T6LSXTSPOFN2k=; b=DNSrUbc215fWUv/OLp0YbpYhCe/vyBLvBGQe4ZzEkD5fMHlvpiEk/BvqPtN4vYFqKa2Hg1 DlWwsuBUQK4qoE2u4RwvdCXs5Y0vwdks5S5TT30U3vSO1tnzMOXtTG0+XtqJOb1BONsOWK CHFuTp9yNMjkivPu36wNoVrAzvMw0Lg= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-44-SXIgS_btNMG0Kxbui_IgRg-1; Sun, 29 Sep 2024 12:34:52 -0400 X-MC-Unique: SXIgS_btNMG0Kxbui_IgRg-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (unknown [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AD851190ECE8 for ; Sun, 29 Sep 2024 16:34:51 +0000 (UTC) Received: from oldenburg.str.redhat.com (unknown [10.45.224.151]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B9AC61979061 for ; Sun, 29 Sep 2024 16:34:50 +0000 (UTC) From: Florian Weimer To: libc-alpha@sourceware.org Subject: [PATCH v3 22/29] elf: Extract rtld_setup_phdr function from dl_main In-Reply-To: Message-ID: <50e5862208a5814248c0c4ff3c496cff1d9f20d0.1727624528.git.fweimer@redhat.com> References: X-From-Line: 50e5862208a5814248c0c4ff3c496cff1d9f20d0 Mon Sep 17 00:00:00 2001 Date: Sun, 29 Sep 2024 18:34:47 +0200 User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-Spam-Status: No, score=-10.8 required=5.0 tests=BAYES_00, DKIMWL_WL_HIGH, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, GIT_PATCH_0, RCVD_IN_MSPIKE_H3, RCVD_IN_MSPIKE_WL, 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 X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.30 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: libc-alpha-bounces~incoming=patchwork.ozlabs.org@sourceware.org Remove historic binutils reference from comment and update how this data is used by applications. --- elf/rtld.c | 58 +++++++++++++++++++++++++++++------------------------- 1 file changed, 31 insertions(+), 27 deletions(-) diff --git a/elf/rtld.c b/elf/rtld.c index cb6b61d570..50c01b9bb4 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -1260,6 +1260,36 @@ rtld_setup_main_map (struct link_map *main_map) return has_interp; } +/* Set up the program header information for the dynamic linker + itself. It can be accessed via _r_debug and dl_iterate_phdr + callbacks. */ +static void +rtld_setup_phdr (void) +{ + /* Starting from binutils-2.23, the linker will define the magic + symbol __ehdr_start to point to our own ELF header if it is + visible in a segment that also includes the phdrs. */ + + const ElfW(Ehdr) *rtld_ehdr = &__ehdr_start; + assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr); + assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr))); + + const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff; + + GL(dl_rtld_map).l_phdr = rtld_phdr; + GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum; + + /* PT_GNU_RELRO is usually the last phdr. */ + size_t cnt = rtld_ehdr->e_phnum; + while (cnt-- > 0) + if (rtld_phdr[cnt].p_type == PT_GNU_RELRO) + { + GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr; + GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz; + break; + } +} + /* Adjusts the contents of the stack and related globals for the user entry point. The ld.so processed skip_args arguments and bumped _dl_argv and _dl_argc accordingly. Those arguments are removed from @@ -1730,33 +1760,7 @@ dl_main (const ElfW(Phdr) *phdr, ++GL(dl_ns)[LM_ID_BASE]._ns_nloaded; ++GL(dl_load_adds); - /* Starting from binutils-2.23, the linker will define the magic symbol - __ehdr_start to point to our own ELF header if it is visible in a - segment that also includes the phdrs. If that's not available, we use - the old method that assumes the beginning of the file is part of the - lowest-addressed PT_LOAD segment. */ - - /* Set up the program header information for the dynamic linker - itself. It is needed in the dl_iterate_phdr callbacks. */ - const ElfW(Ehdr) *rtld_ehdr = &__ehdr_start; - assert (rtld_ehdr->e_ehsize == sizeof *rtld_ehdr); - assert (rtld_ehdr->e_phentsize == sizeof (ElfW(Phdr))); - - const ElfW(Phdr) *rtld_phdr = (const void *) rtld_ehdr + rtld_ehdr->e_phoff; - - GL(dl_rtld_map).l_phdr = rtld_phdr; - GL(dl_rtld_map).l_phnum = rtld_ehdr->e_phnum; - - - /* PT_GNU_RELRO is usually the last phdr. */ - size_t cnt = rtld_ehdr->e_phnum; - while (cnt-- > 0) - if (rtld_phdr[cnt].p_type == PT_GNU_RELRO) - { - GL(dl_rtld_map).l_relro_addr = rtld_phdr[cnt].p_vaddr; - GL(dl_rtld_map).l_relro_size = rtld_phdr[cnt].p_memsz; - break; - } + rtld_setup_phdr (); /* Add the dynamic linker to the TLS list if it also uses TLS. */ if (GL(dl_rtld_map).l_tls_blocksize != 0)