setregid - set real and effective group IDs
int setregid(gid_t rgid, gid_t egid);
The setregid() function is used to set the real and effec-
tive group IDs of the calling process. If rgid is -1, the
real group ID is not changed; if egid is -1, the effective
group ID is not changed. The real and effective group IDs
may be set to different values in the same call.
If the effective user ID of the calling process is super-
user, the real group ID and the effective group ID can be
set to any legal value.
If the effective user ID of the calling process is not
super-user, either the real group ID can be set to the saved
set-group-ID from execve(2), or the effective group ID can
either be set to the saved set-group-ID or the real group
In either case, if the real group ID is being changed (that
is, if rgid is not -1), or the effective group ID is being
changed to a value not equal to the real group ID, the saved
set-group-ID is set equal to the new effective group ID.
Upon successful completion, 0 is returned. Otherwise, -1 is
returned, errno is set to indicate the error, and neither of
the group IDs will be changed.
The setregid() function will fail if:
The value of rgid or egid is less than 0 or greater
than UID_MAX (defined in <limits.h>).
EPERM The calling process's effective UID is not the super-
user and a change other than changing the real group
ID to the saved set-group-ID or changing the effective
group ID to the real group ID or the saved group ID,
If a set-group-ID process sets its effective group ID to its
real group ID, it can still set its effective group ID back
to the saved set-group-ID.
execve(2), getgid(2), setreuid(2), setuid(2)
Man(1) output converted with