UNDELETE(2) BSD System Calls Manual UNDELETE(2)NAMEundelete — attempt to recover a deleted file
undelete(const char *path);
The undelete() function attempts to recover the deleted file named by
path. Currently, this works only when the named object is a whiteout in
a union filesystem. 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 filesys‐
tems able to recover deleted files such as the log-structured filesystem.
Upon successful completion, a value of 0 is returned. Otherwise, a value
of -1 is returned and errno is set to indicate the error.
The undelete() succeeds unless:
[ENOTDIR] A component of the path prefix is not a directory.
[EINVAL] The pathname contains a character with the high-order bit
[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 path
[EACCES] Write permission is denied on the directory containing
the name to be undeleted.
[ELOOP] Too many symbolic links were encountered in translating
[EPERM] The directory containing the name is marked sticky, and
the containing directory is not owned by the effective
[EIO] An I/O error occurred while updating the directory entry.
[EROFS] The name resides on a read-only file system.
[EFAULT] Path points outside the process's allocated address
SEE ALSOunlink(2), mount_union(8)HISTORY
An undelete function call first appeared in 4.4BSD-Lite.
4th Berkeley Distribution October 18, 1994 4th Berkeley Distribution