System Calls                                            setuid(2)



NAME
     setuid, setegid, seteuid, setgid - set user and group IDs

SYNOPSIS
     #include 
     #include 

     int setuid(uidt uid);


     int setgid(gidt gid);


     int seteuid(uidt euid);


     int setegid(gidt egid);


DESCRIPTION
     The setuid() function sets the real user ID, effective  user
     ID,  and  saved user ID of the calling process. The setgid()
     function sets the real group ID,  effective  group  ID,  and
     saved  group  ID  of  the calling process. The setegid() and
     seteuid() functions set the effective  group  and  user  IDs
     respectively  for the calling process. See Intro(2) for more
     information on real, effective, and  saved  user  and  group
     IDs.


     At login time, the real user  ID,  effective  user  ID,  and
     saved  user  ID of the login process are set to the login ID
     of the user responsible for the creation of the process. The
     same  is  true for the real, effective, and saved group IDs;
     they are set to the group ID of the user responsible for the
     creation of the process.


     When a process calls one of the exec(2) family of  functions
     to  execute a file (program), the user and/or group identif-
     iers associated with the process can  change.  If  the  file
     executed is a set-user-ID file, the effective and saved user
     IDs of the process are set to the owner  of  the  file  exe-
     cuted.  If  the  file  executed  is a set-group-ID file, the
     effective and saved group IDs of the process are set to  the
     group  of  the  file executed. If the file executed is not a
     set-user-ID or set-group-ID file,  the  effective  user  ID,
     saved  user  ID,  effective group ID, and saved group ID are
     not changed.






SunOS 5.11          Last change: 20 Jan 2003                    1






System Calls                                            setuid(2)



     If the {PRIVPROCSETID} privilege is asserted in the effec-
     tive  set  of the process calling setuid(), the real, effec-
     tive, and saved user IDs are set to the  uid  argument.   If
     the  uid  argument  is 0 and none of the saved, effective or
     real  UID  is  0,   additional   restrictions   apply.   See
     privileges(5).


     If the {PRIVPROCSETID} privilege is not  asserted  in  the
     effective  set,  but  uid  is either the real user ID or the
     saved user ID of the calling process, the effective user  ID
     is set to uid.


     If the {PRIVPROCSETID} privilege is asserted in the effec-
     tive  set  of the process calling setgid(), the real, effec-
     tive, and saved group IDs are set to the gid argument.


     If the {PRIVPROCSETID} privilege is not  asserted  in  the
     effective  set,  but  gid is either the real group ID or the
     saved group ID of the calling process, the  effective  group
     ID is set to gid.

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

ERORS
     The setuid() and setgid() functions will fail if:

     EINVAL    The value of uid or gid is out of range.


     EPERM     For setuid() and seteuid(), the  {PRIVPROCSETID}
               privilege  is not asserted in the effective set of
               the calling process and the uid argument does  not
               match  either  the  real  or saved user IDs, or an
               attempt is made to change to UID 0 and none of the
               existing  UIDs  is  0,  in  which  case additional
               privileges are required.

               For setgid() and setegid(), the  {PRIVPROCSETID}
               privilege is not asserted in the effective set and
               the gid argument does not match either the real or
               saved group IDs.


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




SunOS 5.11          Last change: 20 Jan 2003                    2






System Calls                                            setuid(2)



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    
     MT-Level                     Async-Signal-Safe           
    


SEE ALSO
     Intro(2), exec(2), getgroups(2),  getuid(2),  stat.h(3HEAD),
     attributes(5), privileges(5), standards(5)











































SunOS 5.11          Last change: 20 Jan 2003                    3