[LTP] [PATCH v5 0/5] Add fchmodat2 testing suite

[Andrea Cervesato]

This is a patch-set that implements fchmodat2() syscall coverage.
fchmodat2() has been added in kernel 6.6 in order to support
AT_SYMLINK_NOFOLLOW and AT_EMPTY_PATH in fchmodat().
There's no man pages yet, so please take the following links as
main documentation along with kernel source code:

https://www.phoronix.com/news/fchmodat2-For-Linux-6.6
https://lore.kernel.org/lkml/20230824-frohlocken-vorabend-725f6fdaad50@brauner/

***********
* WARNING *
***********

fchmodat2_02 fails with EOPNOTSUPP because of missing feature.
According to documentation, the feature has been implemented in
kernel 6.6, but __in reality__ AT_SYMLINK_NOFOLLOW is not working
on symbolic files. Also kselftests, which are meant to test the
functionality, are not working and they are treating fchmodat2()
syscall failure as SKIP. Please take a look at the following code
before reviewing:

https://github.com/torvalds/linux/blob/8f6a15f095a63a83b096d9b29aaff4f0fbe6f6e6/tools/testing/selftests/fchmodat2/fchmodat2_test.c#L123

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
Changes in v5:
- fchmodat2_01: check for EOPNOTSUPP, added tag and removed kernel
  version in order to let backported feature to be available for testing
- Link to v4: https://lore.kernel.org/r/20240801-fchmodat2-v4-0-7f2f11a53a09@suse.com

Changes in v4:
- add SAFE_FCHMODAT2
- Link to v3: https://lore.kernel.org/r/20240724-fchmodat2-v3-0-1dc7cfc634b8@suse.com

Changes in v3:
- removed fchmodat2.h
- Link to v2: https://lore.kernel.org/r/20240723-fchmodat2-v2-0-e658a98b113e@suse.com

Changes in v2:
- merge first 3 tests into a unique one
- move fchmodat2 in lapi/stat.h
- add test for error checking
- Link to v1: https://lore.kernel.org/r/20240521-fchmodat2-v1-0-191b4a986202@suse.com

---
Andrea Cervesato (5):
      Add SAFE_SYMLINKAT macro
      Add fchmodat2 syscalls definitions
      Add fchmodat2 fallback definition
      Add fchmodat2_01 test
      Add fchmodat2_02 test

 include/lapi/stat.h                                |  16 +++
 include/lapi/syscalls/aarch64.in                   |   1 +
 include/lapi/syscalls/arc.in                       |   1 +
 include/lapi/syscalls/arm.in                       |   1 +
 include/lapi/syscalls/hppa.in                      |   1 +
 include/lapi/syscalls/i386.in                      |   1 +
 include/lapi/syscalls/ia64.in                      |   1 +
 include/lapi/syscalls/loongarch.in                 |   1 +
 include/lapi/syscalls/mips_n32.in                  |   1 +
 include/lapi/syscalls/mips_n64.in                  |   1 +
 include/lapi/syscalls/mips_o32.in                  |   1 +
 include/lapi/syscalls/powerpc.in                   |   1 +
 include/lapi/syscalls/powerpc64.in                 |   1 +
 include/lapi/syscalls/s390.in                      |   1 +
 include/lapi/syscalls/s390x.in                     |   1 +
 include/lapi/syscalls/sh.in                        |   1 +
 include/lapi/syscalls/sparc.in                     |   1 +
 include/lapi/syscalls/sparc64.in                   |   1 +
 include/lapi/syscalls/x86_64.in                    |   1 +
 include/safe_macros_fn.h                           |   4 +
 include/tst_safe_macros.h                          |   3 +
 lib/safe_macros.c                                  |  20 ++++
 runtest/syscalls                                   |   3 +
 testcases/kernel/syscalls/fchmodat2/.gitignore     |   2 +
 testcases/kernel/syscalls/fchmodat2/Makefile       |   7 ++
 testcases/kernel/syscalls/fchmodat2/fchmodat2_01.c | 123 +++++++++++++++++++++
 testcases/kernel/syscalls/fchmodat2/fchmodat2_02.c |  68 ++++++++++++
 27 files changed, 264 insertions(+)
---
base-commit: 8422d4680b21e6576da63c677b5d49f46b477df0
change-id: 20240517-fchmodat2-5b82867d71fc

Best regards,
-- 
Andrea Cervesato <andrea.cervesato@suse.com>