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SETUID(2)                DragonFly System Calls Manual               SETUID(2)


NAME

     setuid, seteuid, setgid, setegid -- set user and group ID


LIBRARY

     Standard C Library (libc, -lc)


SYNOPSIS

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

     int
     setuid(uid_t uid);

     int
     seteuid(uid_t euid);

     int
     setgid(gid_t gid);

     int
     setegid(gid_t egid);


DESCRIPTION

     The setuid() function sets the real and effective user IDs and the saved
     set-user-ID of the current process to the specified value.  The setuid()
     function is permitted if the specified ID is equal to the real user ID or
     the effective user ID of the process, or if the effective user ID is that
     of the super user.

     The setgid() function sets the real and effective group IDs and the saved
     set-group-ID of the current process to the specified value.  The setgid()
     function is permitted if the specified ID is equal to the real group ID
     or the effective group ID of the process, or if the effective user ID is
     that of the super user.

     The seteuid() function (setegid()) sets the effective user ID (group ID)
     of the current process.  The effective user ID may be set to the value of
     the real user ID or the saved set-user-ID (see intro(2) and execve(2));
     in this way, the effective user ID of a set-user-ID executable may be
     toggled by switching to the real user ID, then re-enabled by reverting to
     the set-user-ID value.  Similarly, the effective group ID may be set to
     the value of the real group ID or the saved set-group-ID.


RETURN VALUES

     Upon successful completion, the value 0 is returned; otherwise the
     value -1 is returned and the global variable errno is set to indicate the
     error.


ERRORS

     The functions will fail if:

     [EPERM]            The user is not the super user and the ID specified is
                        not the real, effective ID, or saved ID.


SEE ALSO

     getgid(2), getuid(2), issetugid(2), setregid(2), setreuid(2)


STANDARDS

     The setuid() and setgid() functions are compliant with the ISO/IEC
     9945-1:1990 (``POSIX.1'') specification with _POSIX_SAVED_IDS not defined
     with the permitted extensions from Appendix B.4.2.2.  The seteuid() and
     setegid() functions are extensions based on the POSIX concept of
     _POSIX_SAVED_IDS, and have been proposed for a future revision of the
     standard.


HISTORY

     A setuid() and a setgid() function calls appeared in Version 7 AT&T UNIX.

DragonFly 4.3                    June 4, 1993                    DragonFly 4.3

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