From nobody Tue Apr 7 03:50:45 2026 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 8F02FECAAD1 for ; Wed, 31 Aug 2022 18:26:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232954AbiHaS0o (ORCPT ); Wed, 31 Aug 2022 14:26:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58128 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232861AbiHaSZj (ORCPT ); Wed, 31 Aug 2022 14:25:39 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7ED9C6359 for ; Wed, 31 Aug 2022 11:21:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 2F0AAB8227A for ; Wed, 31 Aug 2022 18:21:52 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 841E9C43149; Wed, 31 Aug 2022 18:21:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1661970110; bh=lwk5wcOOPAaS02+SYW0iG5ev2+vHqTxry4RcwHjG3WQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cG+BIk0oG+YYu4lyAQxuAJiTMvF8FjfkNg76PXl3buiLU+G7o06r9XL7K5OF/+3Pm SMw6tpWHY4byJC03yVcl2S2u1Ai94LTgZDJk9a0VfJ1m6tcBN7bTBr0i0miCmj9paV my1p79uNcbT5IGNEpnx+U4uDjxD7KtHpTz9dQ5TEhDB0Xs0TpIXuF9FfWNya4g2t0R rgCPh01+ZNFINUXsY+1oiYqJnORcY0iLhgEHpd0xeRGO1M37wNI1080SOJzgpZNMyz wRqRPgnCby+ldXYPAJcz8nm/y61PRkr17EyTSbaD3M3WV+d6uc71ZiMI+mqbsVLtSt 1EAvF0YN0xxhw== Received: by paulmck-ThinkPad-P17-Gen-1.home (Postfix, from userid 1000) id E3FCD5C0B00; Wed, 31 Aug 2022 11:21:49 -0700 (PDT) From: "Paul E. McKenney" To: linux-kernel@vger.kernel.org Cc: gwml@vger.gnuweeb.org, kernel-team@fb.com, w@lwt.eu, Willy Tarreau , "Paul E . McKenney" Subject: [PATCH nolibc 10/18] selftests/nolibc: recreate and populate /dev and /proc if missing Date: Wed, 31 Aug 2022 11:21:40 -0700 Message-Id: <20220831182148.2698489-12-paulmck@kernel.org> X-Mailer: git-send-email 2.31.1.189.g2e36527f23 In-Reply-To: <20220831182113.GA2697286@paulmck-ThinkPad-P17-Gen-1> References: <20220831182113.GA2697286@paulmck-ThinkPad-P17-Gen-1> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" From: Willy Tarreau Most of the time the program will be run alone in an initramfs. There is no value in requiring the user to populate /dev and /proc for such tests, we can do it ourselves, and it participates to the tests at the same time. What's done here is that when called as init (getpid()=3D=3D1) we check if /dev exists or create it, if /dev/console and /dev/null exists, otherwise we try to mount a devtmpfs there, and if it fails we fall back to mknod. The console is reopened if stdout was closed. Finally /proc is created and mounted if /proc/self cannot be found. This is sufficient for most tests. Signed-off-by: Willy Tarreau Signed-off-by: Paul E. McKenney --- tools/testing/selftests/nolibc/nolibc-test.c | 56 ++++++++++++++++++++ 1 file changed, 56 insertions(+) diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/s= elftests/nolibc/nolibc-test.c index eeb254749239c..a697182c87f57 100644 --- a/tools/testing/selftests/nolibc/nolibc-test.c +++ b/tools/testing/selftests/nolibc/nolibc-test.c @@ -530,6 +530,54 @@ int run_stdlib(int min, int max) return ret; } =20 +/* prepare what needs to be prepared for pid 1 (stdio, /dev, /proc, etc) */ +int prepare(void) +{ + struct stat stat_buf; + + /* It's possible that /dev doesn't even exist or was not mounted, so + * we'll try to create it, mount it, or create minimal entries into it. + * We want at least /dev/null and /dev/console. + */ + if (stat("/dev/.", &stat_buf) =3D=3D 0 || mkdir("/dev", 0755) =3D=3D 0) { + if (stat("/dev/console", &stat_buf) !=3D 0 || + stat("/dev/null", &stat_buf) !=3D 0) { + /* try devtmpfs first, otherwise fall back to manual creation */ + if (mount("/dev", "/dev", "devtmpfs", 0, 0) !=3D 0) { + mknod("/dev/console", 0600 | S_IFCHR, makedev(5, 1)); + mknod("/dev/null", 0666 | S_IFCHR, makedev(1, 3)); + } + } + } + + /* If no /dev/console was found before calling init, stdio is closed so + * we need to reopen it from /dev/console. If it failed above, it will + * still fail here and we cannot emit a message anyway. + */ + if (close(dup(1)) =3D=3D -1) { + int fd =3D open("/dev/console", O_RDWR); + + if (fd >=3D 0) { + if (fd !=3D 0) + dup2(fd, 0); + if (fd !=3D 1) + dup2(fd, 1); + if (fd !=3D 2) + dup2(fd, 2); + if (fd > 2) + close(fd); + puts("\nSuccessfully reopened /dev/console."); + } + } + + /* try to mount /proc if not mounted. Silently fail otherwise */ + if (stat("/proc/.", &stat_buf) =3D=3D 0 || mkdir("/proc", 0755) =3D=3D 0)= { + if (stat("/proc/self", &stat_buf) !=3D 0) + mount("/proc", "/proc", "proc", 0, 0); + } + + return 0; +} =20 /* This is the definition of known test names, with their functions */ static struct test test_names[] =3D { @@ -550,6 +598,14 @@ int main(int argc, char **argv, char **envp) =20 environ =3D envp; =20 + /* when called as init, it's possible that no console was opened, for + * example if no /dev file system was provided. We'll check that fd#1 + * was opened, and if not we'll attempt to create and open /dev/console + * and /dev/null that we'll use for later tests. + */ + if (getpid() =3D=3D 1) + prepare(); + /* the definition of a series of tests comes from either argv[1] or the * "NOLIBC_TEST" environment variable. It's made of a comma-delimited * series of test names and optional ranges: --=20 2.31.1.189.g2e36527f23