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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BA01C001B0 for ; Mon, 3 Jul 2023 06:03:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230003AbjGCGDs (ORCPT ); Mon, 3 Jul 2023 02:03:48 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35564 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229943AbjGCGDp (ORCPT ); Mon, 3 Jul 2023 02:03:45 -0400 Received: from bg4.exmail.qq.com (bg4.exmail.qq.com [43.155.65.254]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C1E88BB; Sun, 2 Jul 2023 23:03:41 -0700 (PDT) X-QQ-mid: bizesmtp68t1688364205t17ezhh7 Received: from linux-lab-host.localdomain ( [119.123.131.49]) by bizesmtp.qq.com (ESMTP) with id ; Mon, 03 Jul 2023 14:03:24 +0800 (CST) X-QQ-SSF: 01200000000000D0W000000A0000000 X-QQ-FEAT: ZgHZPTZ8fzM2scasbR4KDNmzDJ57tOJaycJ/uri88ZY5e961v5sezP2d2eDKd 3MdVLM6sDzieW/jVdp4RNJ3nRvnXbXxXbGuQPhrYGOS3e/iPaCcunS/dl8B8d0KuCs7Rsmd JI8jk7TEjFMrn0lSPIoSvYGnrMwVR9p1BoIABpJsWbowe1RNCD+wpl1I4PSJ4nRE/Oa3FQY HRG0QxFy7CrQlfKOlUOphW+aVbdrXa4K869Z8zz5tGD5nPCJrcaT8fWKqXoYo/lohCk/+tA D0NTEWTwXJpfmls1KsrvfSeqtvAfzFPbkZhkNBlzorNCEacgiiPis39vsCRU442licX8Ol2 hGnzTZOUkila+j5Mho= X-QQ-GoodBg: 0 X-BIZMAIL-ID: 11292108538094942741 From: Zhangjin Wu To: w@1wt.eu Cc: arnd@arndb.de, david.laight@aculab.com, falcon@tinylab.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-riscv@lists.infradead.org, linux@weissschuh.net, thomas@t-8ch.de Subject: Re: [PATCH v5 14/14] selftests/nolibc: add mmap and munmap test cases Date: Mon, 3 Jul 2023 14:03:23 +0800 Message-Id: <20230703060323.487347-1-falcon@tinylab.org> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230702193306.GK16233@1wt.eu> References: <20230702193306.GK16233@1wt.eu> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-QQ-SENDSIZE: 520 Feedback-ID: bizesmtp:tinylab.org:qybglogicsvrgz:qybglogicsvrgz5a-1 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Hi Zhangjin, > > On Wed, Jun 28, 2023 at 09:51:57PM +0800, Zhangjin Wu wrote: > > Three mmap/munmap related test cases are added: > > > > - mmap_bad: the length argument must be greater than 0, otherwise, fail > > with -EINVAL. > > > > - munmap_bad: invalid (void *)-1 address fail with -EINVAL. > > > > - mmap_munmap_good: mmap() a file with good offset and then munmap(). > > > > Note, it is not easy to find a unique file for mmap() in different > > scenes, so, a file list is used to search the right one: > > > > - /proc/1/exe, for 'run' and 'run-user' target > > 'run-user' can not find '/proc/self/exe' > > > > - /proc/self/exe, for 'libc-test' target > > normal program 'libc-test' has no permission to access '/proc/1/exe' > > Strictly speaking, if your executable is not readable (e.g. chmod 111 > due to a restrictive umask) it will also fail that one. > ok. > > - the others, for kernel without procfs > > let it pass even with 'worst case' kernel configs > > You should include /dev/zero, which is commonly used to allocate anonymous > memory and is more likely present and readable than any of the other files. > And another file of choice is obviously argv[0] ;-) In this case you don't > need any of the other extra ones. Thus I could suggest that you try in this > order: > > /dev/zero, /proc/self/exe, /proc/1/exe, argv[0] > > and be done with it. That doesn't prevent one from extending the list if > really needed later, but I doubt it would be needed. Also, it's already > arranged in a read-write, then read-only fallbacks mode, so if we later > need to add more complex tests involving writes, the writable /dev/zero > will have precedence. > Cool, both /dev/zero and argv[0] are very good candidates ;-) Just verified both of them, works perfectly. - /dev/zero we need to mknod it in prepare() and also, in test_mmap_munmap(), stat() return a zero size of /dev/zero, in this case, we should assign a non-zero file_size ourselves. - file_size = stat_buf.st_size; + /* file size of the special /dev/zero is 0, let's assign one manually */ + if (i == 0) + file_size = 3*page_size - 1; + else + file_size = stat_buf.st_size; - argv[0] since nolibc has no realpath() currently, we can simply support the current path and the absolute path like this: nolibc-test.c: /* assigned as argv[0] in main(), will be used by some tests */ static char exe[PATH_MAX + 1]; main(): /* get absolute path of myself, nolibc has no realpath() currently */ #ifndef NOLIBC realpath(argv[0], exe); #else /* assume absolute path has no "./" */ if (strncmp(argv[0], "./", 2) != 0) strncat(exe, argv[0], strlen(argv[0]) + 1); else { pwd = getenv("PWD"); /* skip the ending '\0' */ strncat(exe, getenv("PWD"), strlen(pwd)); /* skip the first '.' */ strncat(exe, argv[0] + 1, strlen(argv[0])); } #endif A full functional realpath() is a little complex, such as '../' support and even symlink support, let's delay its requirement at current stage ;-) one or both of them may also help the other test cases: - chroot_exe (used '/init' before) CASE_TEST(chroot_exe); EXPECT_SYSER(1, chroot(proc ? "/proc/self/exe" : exe), -1, ENOTDIR); break; - chmod_exe (replace the one: chmod_tmpdir in another patchset) CASE_TEST(chmod_exe); EXPECT_SYSZR(1, chmod(proc ? "/proc/self/exe" : exe, 0555)); break; It should be safe enough to only remove the writable attribute for the test program. - stat_timestamps (used '/init' before) if (stat("/proc/self/", &st) && stat(exe, &st) && stat("/dev/zero", &st) && stat("/", &st)) Will update the related patches with them. Thanks, Zhangjin > Willy