UNDELETE(2) BSD System Calls Manual UNDELETE(2)NAMEundelete — attempt to recover a deleted file
Standard C Library (libc, -lc)
undelete(const char *path);
The undelete() system call attempts to recover the deleted file named by
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.
Eventually, the undelete() functionality may be expanded to other file
systems able to recover deleted files such as the log-structured file
The undelete() function returns the value 0 if successful; otherwise the
value -1 is returned and the global variable errno is set to indicate the
The undelete() succeeds unless:
[ENOTDIR] A component of the path prefix is not a directory.
[ENAMETOOLONG] A component of a pathname exceeded 255 characters, or
an entire path name exceeded 1023 characters.
[EEXIST] The path does not reference a whiteout.
[ENOENT] The named whiteout does not exist.
[EACCES] Search permission is denied for a component of the
[EACCES] Write permission is denied on the directory containing
the name to be undeleted.
[ELOOP] Too many symbolic links were encountered in translat‐
ing the pathname.
[EPERM] The directory containing the name is marked sticky,
and the containing directory is not owned by the
effective user ID.
[EINVAL] The last component of the path is ‘..’.
[EIO] An I/O error occurred while updating the directory
[EROFS] The name resides on a read-only file system.
[EFAULT] The path argument points outside the process's allo‐
cated address space.
SEE ALSOunlink(2), mount_unionfs(8)HISTORY
The undelete() system call first appeared in 4.4BSD-Lite.
BSD January 22, 2006 BSD