setuid(2)							   setuid(2)




 NAME
      setuid(), setgid() - set user and group IDs

 SYNOPSIS
      #include <unistd.h>

      int setuid(uid_t uid);

      int setgid(gid_t gid);

 DESCRIPTION
      setuid() sets the real-user-ID (ruid), effective-user-ID (euid),
      and/or saved-user-ID (suid) of the calling process.  If the Security
      Containment product is installed, these interfaces treat a process
      observing CHSUBJIDENT as a privileged process.  Otherwise, only
      processes with an euid of zero are treated as privileged processes.
      See privileges(5) for more information on Security Containment and
      fine-grained privileges.

      The following conditions govern setuid's behavior:

	   +  If the process is privileged, setuid() sets the ruid, euid,
	      and suid to uid.

	   +  If the process is not privileged and the argument uid is equal
	      to the ruid or the suid, setuid() sets the euid to uid; the
	      ruid and suid remain unchanged.  (If a set-user-ID program is
	      not running as superuser, it can change its euid to match its
	      ruid and reset itself to the previous euid value.)

	   +  If the process is not privileged, the argument uid is equal to
	      the euid, and the calling process has the PRIV_SETRUGID
	      privilege, setuid() sets the ruid to uid; the euid and suid
	      remain unchanged.

      setgid() sets the real-group-ID (rgid), effective-group-ID (egid),
      and/or saved-group-ID (sgid) of the calling process.  The following
      conditions govern setgid()'s behavior:

	   +  If the process is privileged, setgid() sets the rgid and egid
	      to gid.

	   +  If the process is not privileged and the argument gid is equal
	      to the rgid or the sgid, setgid() sets the egid to gid; the
	      rgid and sgid remain unchanged.

	   +  If the process is not privileged, the argument gid is equal to
	      the egid, and the calling process has the PRIV_SETRUGID
	      privilege, setgid() sets the rgid to gid; the egid and sgid
	      remain unchanged.




 Hewlett-Packard Company	    - 1 -      HP-UX 11i Version 2: May 2006






 setuid(2)							   setuid(2)




    Security Restrictions
      Some or all of the actions associated with this system call require
      the CHSUBJIDENT privilege.  Processes owned by the superuser have this
      privilege.  Processes owned by other users may have this privilege,
      depending on system configuration.

      See privileges(5) for more information about privileged access on
      systems that support fine-grained privileges.

 RETURN VALUE
      Upon successful completion, setuid() and setgid() return 0; otherwise,
      they return -1 and set errno to indicate the error.

 ERRORS
      setuid() and setgid() fail and return -1 if any of the following
      conditions are encountered:

	   [EPERM]	  None of the conditions above are met.

	   [EINVAL]	  uid (gid) is not a valid user (group) ID.

 WARNINGS
      It is recommended that the PRIV_SETRUGID capability be avoided, as it
      is provided for backward compatibility.  This feature may be modified
      or dropped from future HP-UX releases.  When changing the real user ID
      and real group ID, use of setresuid() and setresgid() (see
      setresuid(2)) is recommended instead.

 AUTHOR
      setuid() was developed by AT&T, the University of California,
      Berkeley, and HP.

      setgid() was developed by AT&T.

 SEE ALSO
      exec(2), getuid(2), setresuid(2), privileges(5).

 STANDARDS CONFORMANCE
      setuid(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1

      setgid(): AES, SVID2, SVID3, XPG2, XPG3, XPG4, FIPS 151-2, POSIX.1













 Hewlett-Packard Company	    - 2 -      HP-UX 11i Version 2: May 2006