sys/setreuid.2

   1 .\" Copyright (c) 1980, 1991, 1993, 1994
   2 .\"     The Regents of the University of California.  All rights reserved.
   3 .\"
   4 .\" Redistribution and use in source and binary forms, with or without
   5 .\" modification, are permitted provided that the following conditions
   6 .\" are met:
   7 .\" 1. Redistributions of source code must retain the above copyright
   8 .\"    notice, this list of conditions and the following disclaimer.
   9 .\" 2. Redistributions in binary form must reproduce the above copyright
  10 .\"    notice, this list of conditions and the following disclaimer in the
  11 .\"    documentation and/or other materials provided with the distribution.
  12 .\" 3. All advertising materials mentioning features or use of this software
  13 .\"    must display the following acknowledgement:
  14 .\"     This product includes software developed by the University of
  15 .\"     California, Berkeley and its contributors.
  16 .\" 4. Neither the name of the University nor the names of its contributors
  17 .\"    may be used to endorse or promote products derived from this software
  18 .\"    without specific prior written permission.
  19 .\"
  20 .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21 .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22 .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23 .\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24 .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25 .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26 .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27 .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28 .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30 .\" SUCH DAMAGE.
  31 .\"
  32 .\"     @(#)setreuid.2  8.2 (Berkeley) 4/16/94
  33 .\" $FreeBSD: src/lib/libc/sys/setreuid.2,v 1.6.2.6 2001/12/14 18:34:01 ru Exp $
  34 .\"
  35 .Dd February 8, 2001
  36 .Dt SETREUID 2
  37 .Os
  38 .Sh NAME
  39 .Nm setreuid
  40 .Nd set real and effective user IDs
  41 .Sh LIBRARY
  42 .Lb libc
  43 .Sh SYNOPSIS
  44 .In unistd.h
  45 .Ft int
  46 .Fn setreuid "uid_t ruid" "uid_t euid"
  47 .Sh DESCRIPTION
  48 The real and effective user IDs of the
  49 current process are set according to the arguments.
  50 If
  51 .Fa ruid
  52 or
  53 .Fa euid
  54 is -1, the current uid is filled in by the system.
  55 Unprivileged users may change the real user
  56 ID to the effective user ID and vice-versa; only the super-user may
  57 make other changes.
  58 .Pp
  59 The
  60 .Fn setreuid
  61 function has been used to swap the real and effective user IDs
  62 in set-user-ID programs to temporarily relinquish the set-user-ID value.
  63 This purpose is now better served by the use of the
  64 .Fn seteuid
  65 function (see
  66 .Xr setuid 2 ) .
  67 .Pp
  68 When setting the real and effective user IDs to the same value,
  69 the standard
  70 .Fn setuid
  71 function is preferred.
  72 .Sh RETURN VALUES
  73 .Rv -std setreuid
  74 .Sh ERRORS
  75 .Bl -tag -width Er
  76 .It Bq Er EPERM
  77 The current process is not the super-user and a change
  78 other than changing the effective user-id to the real user-id
  79 was specified.
  80 .El
  81 .Sh SEE ALSO
  82 .Xr getuid 2 ,
  83 .Xr issetugid 2 ,
  84 .Xr seteuid 2 ,
  85 .Xr setuid 2
  86 .Sh HISTORY
  87 The
  88 .Fn setreuid
  89 system call appeared in
  90 .Bx 4.2 .