From: Willy Tarreau <w@1wt.eu>
To: "Paul E . McKenney" <paulmck@kernel.org>
Cc: Pranith Kumar <bobby.prani@gmail.com>,
Alviro Iskandar Setiawan <alviro.iskandar@gnuweeb.org>,
Ammar Faizi <ammarfaizi2@gnuweeb.org>,
David Laight <David.Laight@ACULAB.COM>,
Mark Brown <broonie@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Shuah Khan <shuah@kernel.org>,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
Willy Tarreau <w@1wt.eu>
Subject: [PATCH 10/17] selftests/nolibc: recreate and populate /dev and /proc if missing
Date: Tue, 19 Jul 2022 23:44:42 +0200 [thread overview]
Message-ID: <20220719214449.2520-12-w@1wt.eu> (raw)
In-Reply-To: <20220719214449.2520-1-w@1wt.eu>
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 <w@1wt.eu>
---
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 45793b6f2244..0bbfe0b3b648 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:
--
2.17.5
next prev parent reply other threads:[~2022-07-19 21:45 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-19 21:44 [PATCH 00/17] nolibc: add preliminary self tests Willy Tarreau
2022-07-19 21:44 ` [PATCH 01/17] tools/nolibc: make argc 32-bit in riscv startup code Willy Tarreau
2022-07-19 21:44 ` [PATCH 02/17] tools/nolibc: fix build warning in sys_mmap() when my_syscall6 is not defined Willy Tarreau
2022-07-19 21:44 ` [PATCH 03/17] tools/nolibc: make sys_mmap() automatically use the right __NR_mmap definition Willy Tarreau
2022-07-19 21:44 ` [PATCH 04/17] selftests/nolibc: add basic infrastructure to ease creation of nolibc tests Willy Tarreau
2022-07-19 21:44 ` [PATCH 05/17] selftests/nolibc: support a test definition format Willy Tarreau
2022-07-19 21:44 ` [PATCH 06/17] selftests/nolibc: implement a few tests for various syscalls Willy Tarreau
2022-07-19 21:44 ` [PATCH 07/17] selftests/nolibc: add a few tests for some libc functions Willy Tarreau
2022-07-19 21:44 ` [PATCH 07/17] selftests/nolibc: add a few tests for some stdlib functions Willy Tarreau
2022-07-19 21:44 ` [PATCH 08/17] selftests/nolibc: exit with poweroff on success when getpid() == 1 Willy Tarreau
2022-07-19 21:44 ` [PATCH 09/17] selftests/nolibc: on x86, support exiting with isa-debug-exit Willy Tarreau
2022-07-19 21:44 ` Willy Tarreau [this message]
2022-07-19 21:44 ` [PATCH 11/17] selftests/nolibc: condition some tests on /proc existence Willy Tarreau
2022-07-19 21:44 ` [PATCH 12/17] selftests/nolibc: support glibc as well Willy Tarreau
2022-07-19 21:44 ` [PATCH 13/17] selftests/nolibc: add a "kernel" target to build the kernel with the initramfs Willy Tarreau
2022-07-19 21:44 ` [PATCH 14/17] selftests/nolibc: add a "defconfig" target Willy Tarreau
2022-07-19 21:44 ` [PATCH 15/17] selftests/nolibc: add a "run" target to start the kernel in QEMU Willy Tarreau
2022-07-19 21:44 ` [PATCH 16/17] selftests/nolibc: "sysroot" target installs a local copy of the sysroot Willy Tarreau
2022-07-19 21:44 ` [PATCH 17/17] selftests/nolibc: add a "help" target Willy Tarreau
2022-07-19 22:49 ` [PATCH 00/17] nolibc: add preliminary self tests Paul E. McKenney
2022-07-20 3:26 ` Willy Tarreau
2022-07-20 16:03 ` Ammar Faizi
2022-07-20 16:20 ` Willy Tarreau
2022-07-20 17:05 ` Ammar Faizi
2022-07-20 17:14 ` Willy Tarreau
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