Track supplementary GIDs per task group, wire setgroups/getgroups
syscalls when CONFIG_SCHED_NGROUPS > 0, and honor them in DAC checks
via nxsched_has_gid(). When NGROUPS is 0, libc provides getgroups/
setgroups stubs. initgroups() fails instead of silently truncating
when membership exceeds CONFIG_SCHED_NGROUPS.
Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
Adds a pre-load permission check in exec_internal() to verify the
calling task has the required execute (x) bits for the target file.
Properly evaluates root (euid == 0), owner, group, and other permissions.
This ensures POSIX compliance and cleanly rejects unauthorized files
with -EACCES before they reach the ELF loader, preventing unnecessary
memory allocation and downstream hardware execution faults.
Signed-off-by: Abhishek Mishra <mishra.abhishek2808@gmail.com>
