.\"	$NetBSD: revoke.2,v 1.16 2014/11/11 08:10:02 njoly Exp $
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.\"     @(#)revoke.2	8.1 (Berkeley) 6/4/93
.\"
.Dd July 3, 2011
.Dt REVOKE 2
.Os
.Sh NAME
.Nm revoke
.Nd revoke file access
.Sh LIBRARY
.Lb libc
.Sh SYNOPSIS
.In unistd.h
.Ft int
.Fn revoke "const char *path"
.Sh DESCRIPTION
The
.Fn revoke
function invalidates all current open file descriptors in the system
for the file named by
.Fa path .
Subsequent operations on any such descriptors
fail, with the exceptions that a
.Xr read 2
from a character device file which has been revoked
returns a count of zero (end of file),
and a
.Xr close 2
call will succeed.
If the file is a special file for a device which is open,
the device close function
is called as if all open references to the file had been closed.
.Pp
Access to a file may be revoked only by its owner or the super user.
.Pp
The
.Fn revoke
function is normally used to prepare a terminal device for a new login session,
preventing any access by a previous user of the terminal.
.Sh RETURN VALUES
A 0 value indicates that the call succeeded.
A \-1 return value indicates an error occurred and
.Va errno
is set to indicate the reason.
.Sh ERRORS
Access to the named file is revoked unless one of the following:
.Bl -tag -width Er
.It Bq Er EACCES
Search permission is denied for a component of the path prefix.
.It Bq Er EFAULT
.Fa path
points outside the process's allocated address space.
.It Bq Er ELOOP
Too many symbolic links were encountered in translating the pathname.
.It Bq Er ENAMETOOLONG
A component of a pathname exceeded
.Brq Dv NAME_MAX
characters,
or an entire path name exceeded
.Brq Dv PATH_MAX
characters.
.It Bq Er ENOENT
The named file or a component of the path name does not exist.
.It Bq Er ENOTDIR
A component of the path prefix is not a directory.
.It Bq Er EPERM
The caller is neither the owner of the file nor the super user.
.El
.Sh SEE ALSO
.Xr close 2 ,
.Xr dup 2 ,
.Xr fcntl 2 ,
.Xr flock 2 ,
.Xr fstat 2 ,
.Xr read 2 ,
.Xr write 2
.Sh HISTORY
The
.Fn revoke
function was introduced in
.Bx 4.3 Reno .