[LTP] [PATCH 1/2] Refactor setresgit01 test

[Petr Vorel]

Hi Andrea,

> Simplify general structure, using struct passwd only when it's strictly
> needed and use new LTP API.

Rewrite LGTM, but there is a problem with 16-bit version.

Old version when compiled for 64bit it quits with TCONF:

# ./setresgid01_16
...
TCONF  :  utils/compat_16.h:146: 16-bit version of setresgid() is not supported on your platform
TCONF  :  utils/compat_16.h:146: Remaining cases not appropriate for configuration

But when running your patchset it runs the test:
# ./setresgid01_16
...
setresgid01.c:67: TPASS: *tc->exp_rgid == cur_rgid (0)

This was caused by using SAFE_SETRESGID(...) instead of original SETRESGID(),
which is needed to employ the check for 16-bit support.

Therefore I merged with this change:

-       SAFE_SETRESGID(*tc->rgid, *tc->egid, *tc->sgid);
+       TST_EXP_PASS(SETRESGID(*tc->rgid, *tc->egid, *tc->sgid));
+       if (!TST_PASS)
+               return;

Besides using SAFE_SETRESGID() would in failure resulted in TBROK instead of
TFAIL (usually subject of testing should result in TFAIL, not TBROK).

Thanks for your work!

Kind regards,
Petr