bsd/man/man2/setreuid.2

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  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 $
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  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 .