From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on gnuweeb.org X-Spam-Level: X-Spam-Status: No, score=-6.2 required=5.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_HI,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by gnuweeb.org (Postfix) with ESMTPS id 3941980BAE for ; Wed, 31 Aug 2022 18:21:52 +0000 (UTC) Authentication-Results: gnuweeb.org; dkim=pass (2048-bit key; unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20201202 header.b=cG+BIk0o; dkim-atps=neutral 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 dfw.source.kernel.org (Postfix) with ESMTPS id 939E861CE2; Wed, 31 Aug 2022 18:21:51 +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: 8bit List-Id: 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()==1) 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/selftests/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; } +/* 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) == 0 || mkdir("/dev", 0755) == 0) { + if (stat("/dev/console", &stat_buf) != 0 || + stat("/dev/null", &stat_buf) != 0) { + /* try devtmpfs first, otherwise fall back to manual creation */ + if (mount("/dev", "/dev", "devtmpfs", 0, 0) != 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)) == -1) { + int fd = open("/dev/console", O_RDWR); + + if (fd >= 0) { + if (fd != 0) + dup2(fd, 0); + if (fd != 1) + dup2(fd, 1); + if (fd != 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) == 0 || mkdir("/proc", 0755) == 0) { + if (stat("/proc/self", &stat_buf) != 0) + mount("/proc", "/proc", "proc", 0, 0); + } + + return 0; +} /* This is the definition of known test names, with their functions */ static struct test test_names[] = { @@ -550,6 +598,14 @@ int main(int argc, char **argv, char **envp) environ = envp; + /* 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() == 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: -- 2.31.1.189.g2e36527f23