selftests: clone3: remove duplicate defines

Remove duplicate defines which are already included in kernel headers.
MAX_PID_NS_LEVEL macro is used inside kernel only. It isn't exposed to
userspace. So it is never defined in test application. Remove #ifndef in
this case.

Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/clone3: Avoid OS-defined clone_args

As the UAPI headers start to appear in distros, we need to avoid
outdated versions of struct clone_args to be able to test modern
features, named "struct __clone_args". Additionally update the struct
size macro names to match UAPI names.

Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/lkml/20200921075432.u4gis3s2o5qrsb5g@wittgenstein/
Signed-off-by: Kees Cook <keescook@chromium.org>

selftests/clone3: Reorder reporting output

Selftest output reporting was happening before the TAP headers and plan
had been emitted. Move the first test reports later.

Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/clone3: skip if clone3() is ENOSYS

If the clone3() syscall is not implemented we should skip the tests.

Fixes: 41585bbeeef9 ("selftests: add tests for clone3() with *set_tid")
Fixes: 17a810699c18 ("selftests: add tests for clone3()")
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

selftests: add tests for clone3() with *set_tid

This tests clone3() with *set_tid to see if all desired PIDs are working
as expected. The tests are trying multiple invalid input parameters as
well as creating processes while specifying a certain PID in multiple
PID namespaces at the same time.

Additionally this moves common clone3() test code into clone3_selftests.h.

Signed-off-by: Adrian Reber <areber@redhat.com>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191115123621.142252-2-areber@redhat.com
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

tests: test CLONE_CLEAR_SIGHAND

Test that CLONE_CLEAR_SIGHAND resets signal handlers to SIG_DFL for the
child process and that CLONE_CLEAR_SIGHAND and CLONE_SIGHAND are
mutually exclusive.

Cc: Florian Weimer <fweimer@redhat.com>
Cc: libc-alpha@sourceware.org
Cc: linux-api@vger.kernel.org
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191014104538.3096-2-christian.brauner@ubuntu.com