osx man page for pthread_setugid_np

PTHREAD_SETUGID_NP(2)					      BSD System Calls Manual					     PTHREAD_SETUGID_NP(2)

NAME
     pthread_setugid_np -- Set the per-thread userid and single groupid.

SYNOPSIS
     #include <sys/types.h>
     #include <sys/unistd.h>

     int
     pthread_setugid_np(uid_t uid, gid_t gid);

DESCRIPTION
     pthread_setugid_np() changes the current thread's effective, real, and saved userid and groupid to the requested userid and groupid ( uid and
     gid , respectively) and clears all other groupids.

     uid can be the current real userid, KAUTH_UID_NONE, or, if the caller is privileged, any userid.  gid can be the current real groupid or, if
     the caller is priviledged, any single groupid.

     Setting uid to KAUTH_UID_NONE means to "revert to the per process credential".

CAVEATS
     Temporarily restoring root privileges for a non-privileged process is only possible on a per-process basis and not a per-thread basis.

     pthread_setugid_np() is not intended as a privilege escalation mechanism.

     Do not use pthread_setugid_np.2() in a security sensitive situation.

RETURN VALUES
     Upon successful completion, a value of 0 is returned.  Otherwise, -1 is returned and the global variable errno is set to indicate the error.

ERRORS
     pthread_setugid_np() fails if one or more of the following are true:

     [EPERM]		The calling process does not have the correct credentials to set the override identity (i.e. The current credentials do
			not imply "super-user").

     [EPERM]		If uid is set to KAUTH_UID_NONE, the current thread must already be assuming another identity in order to revert back.

     [EPERM]		The current thread cannot already be assuming another identity.

SEE ALSO
     setuid(2) setgid(2) seteuid(2) setegid(2)

BSD
								  October 1, 2008							       BSD