selftests: clone3: Fix incorrect kernel headers search path

Use $(KHDR_INCLUDES) as lookup path for kernel headers. This prevents
building against kernel headers from the build environment in scenarios
where kernel headers are installed into a specific output directory
(O=...).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org
Cc: Ingo Molnar <mingo@redhat.com>
Cc: <stable@vger.kernel.org> # 5.18+
Acked-by: Shuah Khan <skhan@linuxfoundation.org>
Acked-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests/clone3: Fix build error

When compiling the selftests with the -std=gnu99 option the build can
fail with.

Following build error:

test_core.c: In function ‘test_cgcore_destroy’:
test_core.c:87:2: error: ‘for’ loop initial declarations are only
allowed in C99 mode
for (int i = 0; i < 10; i++) {
^
test_core.c:87:2: note: use option -std=c99 or -std=gnu99 to compile

Add -std=gnu99 to the clone3 selftest Makefile to fix this.

Signed-off-by: Xingxing Su <suxingxing@loongson.cn>
Acked-by: Christian Brauner <christian.brauner@ubuntu.com>
Signed-off-by: Shuah Khan <skhan@linuxfoundation.org>

selftests: add clone3() CAP_CHECKPOINT_RESTORE test

This adds a test that changes its UID, uses capabilities to
get CAP_CHECKPOINT_RESTORE and uses clone3() with set_tid to
create a process with a given PID as non-root.

Signed-off-by: Adrian Reber <areber@redhat.com>
Link: https://lore.kernel.org/r/20200719100418.2112740-8-areber@redhat.com
[christian.brauner@ubuntu.com: use TH_LOG() instead of ksft_print_msg()]
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>

selftests: add tests for clone3()

This adds tests for clone3() with different values and sizes
of struct clone_args.

This selftest was initially part of of the clone3() with PID selftest.
After that patch was almost merged Eugene sent out a couple of patches
to fix problems with these test.

This commit now only contains the clone3() selftest after the LPC
decision to rework clone3() with PID to allow setting the PID in
multiple PID namespaces including all of Eugene's patches.

Signed-off-by: Eugene Syromiatnikov <esyr@redhat.com>
Signed-off-by: Adrian Reber <areber@redhat.com>
Reviewed-by: Christian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191112095851.811884-1-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