testing/ostest: multiuser coverage for supplementary groups and setresuid

[Abhishekmishra2808]

Summary

• Expand testing/ostest/multiuser.c for the POSIX credential APIs added in the kernel PR
• Add tests for supplementary groups, setresuid/setresgid ordering, getresuid/setreuid, and saved set-UID/GID child semantics
• Added nsh# for root and nsh$ for user (when login enabled); otherwise, nsh>
• Depends on the companion nuttx PR sched: supplementary groups and setresuid/setresgid nuttx#19767

Impact

This change only extends testing/ostest/multiuser.c to exercise the new kernel credential APIs. It adds coverage for supplementary groups, setresuid/setresgid drop ordering, getresuid/setreuid, and saved set-UID/GID behavior in a child task. Builds without CONFIG_SCHED_USER_IDENTITY are unchanged.

Testing

End of test memory usage:
VARIABLE  BEFORE   AFTER
======== ======== ========
arena     3effff8  3effff8
ordblks         6        6
mxordblk  3eaaa90  3eaaa90
uordblks    45958    45958
fordblks  3eba6a0  3eba6a0

user_main: scheduler lock test
sched_lock: Starting lowpri_thread at 97
sched_lock: Set lowpri_thread priority to 97
sched_lock: Starting highpri_thread at 98
sched_lock: Set highpri_thread priority to 98
sched_lock: Waiting...
sched_lock: PASSED No pre-emption occurred while scheduler was locked.
sched_lock: Starting lowpri_thread at 97
sched_lock: Set lowpri_thread priority to 97
sched_lock: Starting highpri_thread at 98
sched_lock: Set highpri_thread priority to 98
sched_lock: Waiting...
sched_lock: PASSED No pre-emption occurred while scheduler was locked.
sched_lock: Finished

End of test memory usage:
VARIABLE  BEFORE   AFTER
======== ======== ========
arena     3effff8  3effff8
ordblks         6        6
mxordblk  3eaaa90  3eaaa90
uordblks    45958    45958
fordblks  3eba6a0  3eba6a0

Final memory usage:
VARIABLE  BEFORE   AFTER
======== ======== ========
arena     3effff8  3effff8
ordblks         2        6
mxordblk  3eaaa90  3eaaa90
uordblks    45320    45958
fordblks  3ebacd8  3eba6a0
user_main: Exiting
ostest_main: Exiting with status 0
abhishek@Lethallaptop:~/nuttx$ 

[xiaoxiang781216]

@Abhishekmishra2808 please fix ci warning and pr title/description

[linguini1]

Please add a log of your additional OSTest suite passing.

[Abhishekmishra2808]

@linguini1 PTAL at the updated testing logs

[raiden00pl]

@acassis why this was merged ? CI is now broken ...

[linguini1]

The test logs don't even show the multi user test, they show a scheduler lock test. @Abhishekmishra2808

[acassis]

@acassis why this was merged ? CI is now broken ...

The issue was not related to this PR

[raiden00pl]

@acassis are you sure? What about this commit: c67b8bc

[acassis]

@raiden00pl yes, I only saw the issue with toybox defconfig, but that was because it was not normalized

[raiden00pl]

c67b8bc has broken NTFC and it is visible in CI for this PR: https://github.com/apache/nuttx-apps/actions/runs/31743634370/job/94593362401

[raiden00pl]

@acassis this is probably the reason #3690 (comment) CI for apps is broken