plucky (2) setreuid.2freebsd.gz

Provided by: freebsd-manpages_12.2-2_all bug

NAME
     setreuid — set real and effective user ID's


LIBRARY
     Standard C Library (libc, -lc)


SYNOPSIS
     #include <unistd.h>

     int
     setreuid(uid_t ruid, uid_t euid);


DESCRIPTION
     The real and effective user IDs of the current process are set according to the arguments.  If ruid or euid
     is -1, the current uid is filled in by the system.  Unprivileged users may change the real user ID to the
     effective user ID and vice-versa; only the super-user may make other changes.

     If the real user ID is changed (i.e. ruid is not -1) or the effective user ID is changed to something other
     than the real user ID, then the saved user ID will be set to the effective user ID.

     The setreuid() system call has been used to swap the real and effective user IDs in set-user-ID programs to
     temporarily relinquish the set-user-ID value.  This purpose is now better served by the use of the
     seteuid(2) system call.

     When setting the real and effective user IDs to the same value, the standard setuid() system call is
     preferred.


RETURN VALUES
     The setreuid() function returns the value 0 if successful; otherwise the value -1 is returned and the
     global variable errno is set to indicate the error.


ERRORS
     [EPERM]            The current process is not the super-user and a change other than changing the effective
                        user-id to the real user-id was specified.


SEE ALSO
     getuid(2), issetugid(2), seteuid(2), setuid(2)


HISTORY
     The setreuid() system call appeared in 4.2BSD.