From patchwork Mon Mar 30 17:43:36 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Dasmohapatra X-Patchwork-Id: 38667 Return-Path: X-Original-To: libc-alpha@sourceware.org Delivered-To: libc-alpha@sourceware.org Received: from bhuna.collabora.co.uk (bhuna.collabora.co.uk [46.235.227.227]) by sourceware.org (Postfix) with ESMTPS id C28FD385DC37 for ; Mon, 30 Mar 2020 17:43:57 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org C28FD385DC37 Received: from noise.collabora.co.uk (unknown [IPv6:2a00:5f00:102:0:c0a7:51ff:feaf:e642]) (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 04B322966C4; Mon, 30 Mar 2020 18:43:56 +0100 (BST) From: =?utf-8?q?Vivek_Das=C2=A0Mohapatra?= To: vivek@etla.org, libc-alpha@sourceware.org Subject: [RFC][PATCH v4 02/15] include/link.h: Update the link_map struct to allow proxies Date: Mon, 30 Mar 2020 18:43:36 +0100 Message-Id: X-Mailer: git-send-email 2.11.0 In-Reply-To: References: In-Reply-To: References: X-Spam-Status: No, score=-28.8 required=5.0 tests=BAYES_00, GIT_PATCH_0, GIT_PATCH_1, GIT_PATCH_2, GIT_PATCH_3, KAM_DMARC_STATUS, RCVD_IN_DNSWL_NONE, SPF_HELO_PASS, 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: Mon, 30 Mar 2020 17:43:58 -0000 We already have an l_real pointer, used for a similar purpose by the linker for copies of ld.so in secondary namespaces. Update its documentation and add a bitfield to indicate when link_map entry is a proxy. --- include/link.h | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/include/link.h b/include/link.h index aea268439c..c63166317d 100644 --- a/include/link.h +++ b/include/link.h @@ -103,8 +103,9 @@ struct link_map They may change without notice. */ /* This is an element which is only ever different from a pointer to - the very same copy of this type for ld.so when it is used in more - than one namespace. */ + the very same copy of this type when: + - A shallow copy of ld.so is placed in namespaces other than LM_ID_BASE. + - An object is proxied into a namespace by dlmopen with RTLD_SHARED. */ struct link_map *l_real; /* Number of the namespace this link map belongs to. */ @@ -176,6 +177,7 @@ struct link_map unsigned int l_relocated:1; /* Nonzero if object's relocations done. */ unsigned int l_init_called:1; /* Nonzero if DT_INIT function called. */ unsigned int l_global:1; /* Nonzero if object in _dl_global_scope. */ + unsigned int l_proxy:1; /* Nonzero if object is a shallow copy. */ unsigned int l_reserved:2; /* Reserved for internal use. */ unsigned int l_phdr_allocated:1; /* Nonzero if the data structure pointed to by `l_phdr' is allocated. */