System Calls                                          setreuid(2)



NAME
     setreuid - set real and effective user IDs

SYNOPSIS
     #include 

     int setreuid(uidt ruid, uidt euid);


DESCRIPTION
     The setreuid() function is used to set the real  and  effec-
     tive  user  IDs  of  the calling process. If ruid is -1, the
     real user ID is not changed; if euid is  -1,  the  effective
     user  ID is not changed. The real and effective user IDs may
     be set to different values in the same call.


     If the {PRIVPROCSETID} privilege is asserted in the effec-
     tive  set  of  the calling process, the real user ID and the
     effective user ID can be set to any legal value.


     If the {PRIVPROCSETID} privilege is not  asserted  in  the
     effective  set  of the calling process, either the real user
     ID can be set to the effective user  ID,  or  the  effective
     user  ID  can  either  be  set to the saved set-user ID from
     execve() (seeexec(2)) or the real user ID.


     In either case, if the real user ID is being  changed  (that
     is,  if  ruid is not  -1), or the effective user ID is being
     changed to a value not equal to the real user ID, the  saved
     set-user ID is set equal to the new effective user ID.


     All privileges are required to change to uid 0.

RETURN VALUES
     Upon successful completion, 0 is returned. Otherwise, -1  is
     returned, errno is set to indicate the error, and neither of
     the user IDs will be changed.

ERORS
     The setreuid() function will fail if:

     EINVAL    The value of ruid or  euid  is  less  than   0  or
               greater than UIDMAX (defined in ).


     EPERM     The {PRIVPROCSETID} privilege is not asserted in
               the  effective  set of the calling processes and a
               change was specified other than changing the  real



SunOS 5.11          Last change: 22 Mar 2004                    1






System Calls                                          setreuid(2)



               user  ID to the effective user ID, or changing the
               effective user ID to the real user ID or the saved
               set-user ID. See privileges(5) for additional res-
               trictions which apply when changing to UID 0.


USAGE
     If a set-user-ID process sets its effective user ID  to  its
     real user ID, it can still set its effective user ID back to
     the saved set-user ID.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    


SEE ALSO
     exec(2), getuid(2), setregid(2),  setuid(2),  attributes(5),
     privileges(5), standards(5)




























SunOS 5.11          Last change: 22 Mar 2004                    2