Make cp preserve the permissions of a directory when copying
it. Before this commit,
cp -pR src/ dest/
failed to copy the permissions of `src/` to `dest/`. After this
commit, the permissions are correctly copied.
Correct the error message produced when attempting to copy a directory
into itself with `cp`. Before this commit, the error message was
$ cp -R d d
cp: cannot copy a directory, 'd', into itself, 'd'
After this commit, the error message is
$ cp -R d d
cp: cannot copy a directory, 'd', into itself, 'd/d'
Move the copy-on-write functions for `cp` to their own module. This
provides a layer of indirection so that the `cp.rs` module need only
use `platform::copy_on_write()`, and the `platform` module is
responsible for providing the appropriate implementation for the
current platform. This commit does not change the behavior of the
code, just its organization.
Allow `cp --remove-destination` to remove a symbolic link loop (or a
symbolic link that initiates a chain of too many symbolic
links). Before this commit, if `loop` were a symbolic link to itself,
then
cp --remove-destination file loop
would fail with an error message. After this commit, it succeeds. This
matches the behaviotr of GNU cp.
`cp` in interactive mode used to write to stdout asking for
overwrite. GNU version writes to stderr.
Changed: write to stderr to make compatible with GNU.
* cp: Refactor `reflink`/`sparse` handling to enable `--sparse` flag
`--sparse` and `--reflink` options have a lot of similarities:
- They have similar options (`always`, `never`, `auto`)
- Both need OS specific handling
- They can be mutually exclusive
Prior to this change, `sparse` was defined as `CopyMode`, but `reflink`
wasn't. Given the similarities, it makes sense to handle them similarly.
The idea behind this change is to move all OS specific file copy
handling in the `copy_on_write_*` functions. Those function then
dispatch to the correct logic depending on the arguments (at the moment,
the tuple `(reflink, sparse)`).
Also, move the handling of `--reflink=never` from `copy_file` to the
`copy_on_write_*` functions, at the cost of a bit of code duplication,
to allow `copy_on_write_*` to handle all cases (and later handle
`--reflink=never` with `--sparse`).
* cp: Implement `--sparse` flag
This begins to address #3362
At the moment, only the `--sparse=always` logic matches the requirement
form GNU cp info page, i.e. always make holes in destination when
possible.
Sparse copy is done by copying the source to the destination block by
block (blocks being of the destination's fs block size). If the block
only holds NUL bytes, we don't write to the destination.
About `--sparse=auto`: according to GNU cp info page, the destination
file will be made sparse if the source file is sparse as well. The next
step are likely to use `lseek` with `SEEK_HOLE` detect if the source
file has holes. Currently, this has the same behaviour as
`--sparse=never`. This `SEEK_HOLE` logic can also be applied to
`--sparse=always` to improve performance when copying sparse files.
About `--sparse=never`: from my understanding, it is not guaranteed that
Rust's `fs::copy` will always produce a file with no holes, as
["platform-specific behavior may change in the
future"](https://doc.rust-lang.org/std/fs/fn.copy.html#platform-specific-behavior)
About other platforms:
- `macos`: The solution may be to use `fcntl` command `F_PUNCHHOLE`.
- `windows`: I only see `FSCTL_SET_SPARSE`.
This should pass the following GNU tests:
- `tests/cp/sparse.sh`
- `tests/cp/sparse-2.sh`
- `tests/cp/sparse-extents.sh`
- `tests/cp/sparse-extents-2.sh`
`sparse-perf.sh` needs `--sparse=auto`, and in particular a way to skip
holes in the source file.
Co-authored-by: Sylvestre Ledru <sylvestre@debian.org>
Add a `uucore::fs::is_symlink()` function that takes in a
`std::path::Path` and decides whether the given path is a symbolic
link. This is essentially a backport of the `Path::is_symlink()`
function that appears in Rust version 1.58.0. This commit also
replaces some now-duplicate code in `chmod`, `cp`, `ln`, and `rmdir`
that checks whether a path is a symbolic link with a call to
`is_symlink()`.
Technically, this commit slightly changes the behavior of
`cp`. Previously, there was a line of code like this
if fs::symlink_metadata(&source)?.file_type().is_symlink() {
where the `?` operator propagates an error from `symlink_metadata()`
to the caller. Now the line of code is
if is_symlink(source) {
in which any error from `symlink_metadata()` has been converted to
just be a `false` value. I believe this is a satisfactory tradeoff to
make, since an error in accessing the file will likely cause an error
later in the same code path.
Fix a bug in which `cp` incorrectly exited with an error when
attempting to copy the attributes of a dangling symbolic link (that
is, when running `cp -P -p`).
Fixes#3531.
Refactor common code used in several places into a convenience
function `is_symlink()` that behaves like `Path::is_symlink()` added
in Rust 1.58.0. (We support earlier versions of Rust so we cannot use
the standard library version of this function.)
When `--backup` is supplied, `cp` will take a backup of *destination* before *source* is copied. When `--backup=simple` is supplied, it is possible for the backup path for *destination* to equal the path for *source*, destroying source before the copy is made. This change prevents this by returning an error instead.
This fixes https://github.com/uutils/coreutils/issues/3629
