From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 65F10CF58FA for ; Fri, 20 Sep 2024 09:33:53 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sra1C-0001ZW-0y; Fri, 20 Sep 2024 05:33:38 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sra1A-0001Tv-IN for qemu-devel@nongnu.org; Fri, 20 Sep 2024 05:33:36 -0400 Received: from mout.kundenserver.de ([212.227.126.134]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sra17-0007C4-VS for qemu-devel@nongnu.org; Fri, 20 Sep 2024 05:33:36 -0400 Received: from [192.168.100.1] ([82.64.211.94]) by mrelayeu.kundenserver.de (mreue012 [213.165.67.103]) with ESMTPSA (Nemesis) id 1M6pck-1stGJP0wsY-005psl; Fri, 20 Sep 2024 11:33:25 +0200 Message-ID: Date: Fri, 20 Sep 2024 11:33:22 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v6 1/1] linux-user: add openat2 support in linux-user To: Michael Vogt , qemu-devel@nongnu.org Cc: Michael Vogt , Richard Henderson References: <65bb234d769980a3b10a655ed19f87966c714e06.1726817664.git.mvogt@redhat.com> Content-Language: fr From: Laurent Vivier Autocrypt: addr=laurent@vivier.eu; keydata= xsFNBFYFJhkBEAC2me7w2+RizYOKZM+vZCx69GTewOwqzHrrHSG07MUAxJ6AY29/+HYf6EY2 WoeuLWDmXE7A3oJoIsRecD6BXHTb0OYS20lS608anr3B0xn5g0BX7es9Mw+hV/pL+63EOCVm SUVTEQwbGQN62guOKnJJJfphbbv82glIC/Ei4Ky8BwZkUuXd7d5NFJKC9/GDrbWdj75cDNQx UZ9XXbXEKY9MHX83Uy7JFoiFDMOVHn55HnncflUncO0zDzY7CxFeQFwYRbsCXOUL9yBtqLer Ky8/yjBskIlNrp0uQSt9LMoMsdSjYLYhvk1StsNPg74+s4u0Q6z45+l8RAsgLw5OLtTa+ePM JyS7OIGNYxAX6eZk1+91a6tnqfyPcMbduxyBaYXn94HUG162BeuyBkbNoIDkB7pCByed1A7q q9/FbuTDwgVGVLYthYSfTtN0Y60OgNkWCMtFwKxRaXt1WFA5ceqinN/XkgA+vf2Ch72zBkJL RBIhfOPFv5f2Hkkj0MvsUXpOWaOjatiu0fpPo6Hw14UEpywke1zN4NKubApQOlNKZZC4hu6/ 8pv2t4HRi7s0K88jQYBRPObjrN5+owtI51xMaYzvPitHQ2053LmgsOdN9EKOqZeHAYG2SmRW LOxYWKX14YkZI5j/TXfKlTpwSMvXho+efN4kgFvFmP6WT+tPnwARAQABzSJMYXVyZW50IFZp dmllciA8bGF1cmVudEB2aXZpZXIuZXU+wsF4BBMBAgAiBQJWBTDeAhsDBgsJCAcDAgYVCAIJ CgsEFgIDAQIeAQIXgAAKCRDzDDi9Py++PCEdD/oD8LD5UWxhQrMQCsUgLlXCSM7sxGLkwmmF ozqSSljEGRhffxZvO35wMFcdX9Z0QOabVoFTKrT04YmvbjsErh/dP5zeM/4EhUByeOS7s6Yl HubMXVQTkak9Wa9Eq6irYC6L41QNzz/oTwNEqL1weV1+XC3TNnht9B76lIaELyrJvRfgsp9M rE+PzGPo5h7QHWdL/Cmu8yOtPLa8Y6l/ywEJ040IoiAUfzRoaJs2csMXf0eU6gVBhCJ4bs91 jtWTXhkzdl4tdV+NOwj3j0ukPy+RjqeL2Ej+bomnPTOW8nAZ32dapmu7Fj7VApuQO/BSIHyO NkowMMjB46yohEepJaJZkcgseaus0x960c4ua/SUm/Nm6vioRsxyUmWd2nG0m089pp8LPopq WfAk1l4GciiMepp1Cxn7cnn1kmG6fhzedXZ/8FzsKjvx/aVeZwoEmucA42uGJ3Vk9TiVdZes lqMITkHqDIpHjC79xzlWkXOsDbA2UY/P18AtgJEZQPXbcrRBtdSifCuXdDfHvI+3exIdTpvj BfbgZAar8x+lcsQBugvktlQWPfAXZu4Shobi3/mDYMEDOE92dnNRD2ChNXg2IuvAL4OW40wh gXlkHC1ZgToNGoYVvGcZFug1NI+vCeCFchX+L3bXyLMg3rAfWMFPAZLzn42plIDMsBs+x2yP +c7BTQRWBSYZARAAvFJBFuX9A6eayxUPFaEczlMbGXugs0mazbOYGlyaWsiyfyc3PStHLFPj rSTaeJpPCjBJErwpZUN4BbpkBpaJiMuVO6egrC8Xy8/cnJakHPR2JPEvmj7Gm/L9DphTcE15 92rxXLesWzGBbuYxKsj8LEnrrvLyi3kNW6B5LY3Id+ZmU8YTQ2zLuGV5tLiWKKxc6s3eMXNq wrJTCzdVd6ThXrmUfAHbcFXOycUyf9vD+s+WKpcZzCXwKgm7x1LKsJx3UhuzT8ier1L363RW ZaJBZ9CTPiu8R5NCSn9V+BnrP3wlFbtLqXp6imGhazT9nJF86b5BVKpF8Vl3F0/Y+UZ4gUwL d9cmDKBcmQU/JaRUSWvvolNu1IewZZu3rFSVgcpdaj7F/1aC0t5vLdx9KQRyEAKvEOtCmP4m 38kU/6r33t3JuTJnkigda4+Sfu5kYGsogeYG6dNyjX5wpK5GJIJikEhdkwcLM+BUOOTi+I9u tX03BGSZo7FW/J7S9y0l5a8nooDs2gBRGmUgYKqQJHCDQyYut+hmcr+BGpUn9/pp2FTWijrP inb/Pc96YDQLQA1q2AeAFv3Rx3XoBTGl0RCY4KZ02c0kX/dm3eKfMX40XMegzlXCrqtzUk+N 8LeipEsnOoAQcEONAWWo1HcgUIgCjhJhBEF0AcELOQzitbJGG5UAEQEAAcLBXwQYAQIACQUC VgUmGQIbDAAKCRDzDDi9Py++PCD3D/9VCtydWDdOyMTJvEMRQGbx0GacqpydMEWbE3kUW0ha US5jz5gyJZHKR3wuf1En/3z+CEAEfP1M3xNGjZvpaKZXrgWaVWfXtGLoWAVTfE231NMQKGoB w2Dzx5ivIqxikXB6AanBSVpRpoaHWb06tPNxDL6SVV9lZpUn03DSR6gZEZvyPheNWkvz7bE6 FcqszV/PNvwm0C5Ju7NlJA8PBAQjkIorGnvN/vonbVh5GsRbhYPOc/JVwNNr63P76rZL8Gk/ hb3xtcIEi5CCzab45+URG/lzc6OV2nTj9Lg0SNcRhFZ2ILE3txrmI+aXmAu26+EkxLLfqCVT ohb2SffQha5KgGlOSBXustQSGH0yzzZVZb+HZPEvx6d/HjQ+t9sO1bCpEgPdZjyMuuMp9N1H ctbwGdQM2Qb5zgXO+8ZSzwC+6rHHIdtcB8PH2j+Nd88dVGYlWFKZ36ELeZxD7iJflsE8E8yg OpKgu3nD0ahBDqANU/ZmNNarBJEwvM2vfusmNnWm3QMIwxNuJghRyuFfx694Im1js0ZY3LEU JGSHFG4ZynA+ZFUPA6Xf0wHeJOxGKCGIyeKORsteIqgnkINW9fnKJw2pgk8qHkwVc3Vu+wGS ZiJK0xFusPQehjWTHn9WjMG1zvQ5TQQHxau/2FkP45+nRPco6vVFQe8JmgtRF8WFJA== In-Reply-To: <65bb234d769980a3b10a655ed19f87966c714e06.1726817664.git.mvogt@redhat.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Provags-ID: V03:K1:o9/e43Fd+DdxSLb2v5sbApdVgjuUsZ85zTKKvV9TpGeXA+0XcWD PSV7MZkPxrw4KwYXFZF0Xi7otBH9OnXceKfkmMiBj1QDH87TcK6NR2JFZ1yp5/QLcgusCxH liMlUDr7lqIfaZ2oUoE2vKVpWEhO53ZMIyt29/3g/59gQnskCk15LPUpq1+eChod+871vTg n0Al1SXqQLpX4lJ1Uq3PQ== UI-OutboundReport: notjunk:1;M01:P0:KcEhh5sRUdc=;P7ROIJaI9xw9SKMptBwYVgsYmPf Vym1dQQR55EfkOLseqsAXN6z6G6aE9SbiLTQAIhyiVNUxbowkMKHY/GD0whu9rg+dgLpwA50n NVghgV3jpvj7D9aizdDXxgt28XdSBlCYok2C+tEMgifgk1C7PYtAbjhRRE/yaMZtm3ZYYusSk 7ZbxWbAZZmUV0Xkd0yY0UayuiltORe5rYlNR5/aVSZnS4Oh1Ru174htMO/0WeoauUvWeY3enG ZF5YQN0KvDAeaw2VYJPEx4RRugeMLu2gN/09OsARYGqTxbOZVqNi0BBcRuvJkeEH7I7NrClKA K1ZnKGv7fsEBhrPcgWWGSpSLm1UD1p9q/x33nIEasVk25hwD8gTjfE5h9obdJx1qpVLdV1MZK 5+tayHST6FXiWoQvaKHn+Ne2Ik4h57bWIFM6lZX3S4h6ZfrOEwYKVq8pTQ4fLb+kMXxHykk4h 8XSSZ0CUQmKeisNJYGFmPP5o05+qxfRbq2e7dNfaAUw0pRQ9dP3LcBqdEfZ1pk6QH+3VCk1bI Tu7A4qgowJPR9jtrRUUcTrnjs4Kvs2bTBOInlzz49ut96rS5pffwcg3zP9wkyVp1XaMtCyN4x pM/ROxfueADrL/zxu8IWuEJDdltcDFlTi8r923pcqK8COve5W5/pm2+G47b7a0oE/NttM4dnC 7S42FLKU+B3pTUL9thu4SegVGCMu8nDldG/Mq2XyuR6mLUpdS24+ugOwKJFTNF9ZqjzGb7HfD d//cbm1q96MZsMFrUORM0lC/KdUqhxKLw== Received-SPF: pass client-ip=212.227.126.134; envelope-from=laurent@vivier.eu; helo=mout.kundenserver.de X-Spam_score_int: -18 X-Spam_score: -1.9 X-Spam_bar: - X-Spam_report: (-1.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Le 20/09/2024 à 11:22, Michael Vogt a écrit : > This commit adds support for the `openat2()` syscall in the > `linux-user` userspace emulator. > > It is implemented by extracting a new helper `maybe_do_fake_open()` > out of the exiting `do_guest_openat()` and share that with the > new `do_guest_openat2()`. Unfortunately we cannot just make > do_guest_openat2() a superset of do_guest_openat() because the > openat2() syscall is stricter with the argument checking and > will return an error for invalid flags or mode combinations (which > open()/openat() will ignore). > > The implementation is similar to SYSCALL_DEFINE(openat2), i.e. > a new `copy_struct_from_user()` is used that works the same > as the kernels version to support backwards-compatibility > for struct syscall argument. > > Instead of including openat2.h we create a copy of `open_how` > as `open_how_ver0` to ensure that if the structure grows we > can log a LOG_UNIMP warning. > > Note that in this commit using openat2() for a "faked" file in > /proc will ignore the "resolve" flags. This is not great but it > seems similar to the exiting behavior when openat() is called > with a dirfd to "/proc". Here too the fake file lookup may > not catch the special file because "realpath()" is used to > determine if the path is in /proc. Alternatively to ignoring > we could simply fail with `-TARGET_ENOSYS` (or similar) if > `resolve` flags are passed and we found something that looks > like a file in /proc that needs faking. > > Signed-off-by: Michael Vogt > Buglink: https://github.com/osbuild/bootc-image-builder/issues/619 > --- > linux-user/syscall.c | 108 +++++++++++++++++++++++++++++++++++++- > linux-user/syscall_defs.h | 7 +++ > 2 files changed, 113 insertions(+), 2 deletions(-) > Reviewed-by: Laurent Vivier