.\" Copyright (c) 1994
.\"	Jan-Simon Pendry
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.\"     @(#)undelete.2	8.4 (Berkeley) 10/18/94
.\" $FreeBSD: head/lib/libc/sys/undelete.2 165903 2007-01-09 00:28:16Z imp $
.\"
.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 .