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+.\" Copyright (c) 1994
+.\"	Jan-Simon Pendry
+.\"	The Regents of the University of California.  All rights reserved.
+.\"
+.\" Redistribution and use in source and binary forms, with or without
+.\" modification, are permitted provided that the following conditions
+.\" are met:
+.\" 1. Redistributions of source code must retain the above copyright
+.\"    notice, this list of conditions and the following disclaimer.
+.\" 2. Redistributions in binary form must reproduce the above copyright
+.\"    notice, this list of conditions and the following disclaimer in the
+.\"    documentation and/or other materials provided with the distribution.
+.\" 4. Neither the name of the University nor the names of its contributors
+.\"    may be used to endorse or promote products derived from this software
+.\"    without specific prior written permission.
+.\"
+.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
+.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
+.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
+.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
+.\" SUCH DAMAGE.
+.\"
+.\"     @(#)undelete.2	8.4 (Berkeley) 10/18/94
+.\" $FreeBSD$
+.\"
+.Dd January 22, 2006
+.Dt UNDELETE 2
+.Os
+.Sh NAME
+.Nm undelete
+.Nd attempt to recover a deleted file
+.Sh LIBRARY
+.Lb libc
+.Sh SYNOPSIS
+.In unistd.h
+.Ft int
+.Fn undelete "const char *path"
+.Sh DESCRIPTION
+The
+.Fn undelete
+system call attempts to recover the deleted file named by
+.Fa path .
+Currently, this works only when the named object
+is a whiteout in a union file system.
+The system call removes the whiteout causing
+any objects in a lower layer of the
+union stack to become visible once more.
+.Pp
+Eventually, the
+.Fn undelete
+functionality may be expanded to other file systems able to recover
+deleted files such as the log-structured file system.
+.Sh RETURN VALUES
+.Rv -std undelete
+.Sh ERRORS
+The
+.Fn undelete
+succeeds unless:
+.Bl -tag -width Er
+.It Bq Er ENOTDIR
+A component of the path prefix is not a directory.
+.It Bq Er ENAMETOOLONG
+A component of a pathname exceeded 255 characters,
+or an entire path name exceeded 1023 characters.
+.It Bq Er EEXIST
+The path does not reference a whiteout.
+.It Bq Er ENOENT
+The named whiteout does not exist.
+.It Bq Er EACCES
+Search permission is denied for a component of the path prefix.
+.It Bq Er EACCES
+Write permission is denied on the directory containing the name
+to be undeleted.
+.It Bq Er ELOOP
+Too many symbolic links were encountered in translating the pathname.
+.It Bq Er EPERM
+The directory containing the name is marked sticky,
+and the containing directory is not owned by the effective user ID.
+.It Bq Er EINVAL
+The last component of the path is
+.Ql .. .
+.It Bq Er EIO
+An I/O error occurred while updating the directory entry.
+.It Bq Er EROFS
+The name resides on a read-only file system.
+.It Bq Er EFAULT
+The
+.Fa path
+argument
+points outside the process's allocated address space.
+.El
+.Sh SEE ALSO
+.Xr unlink 2 ,
+.Xr mount_unionfs 8
+.Sh HISTORY
+The
+.Fn undelete
+system call first appeared in
+.Bx 4.4 Lite .