Different feature.fs.mapping behaviour in different hooks

[t4lz]

For example in read_link (and in some other hooks)

mirrord/mirrord/layer/src/file/ops.rs

Lines 333 to 336 in fd9ef90

	pub(crate) fn read_link(path: Detour<PathBuf>) -> Detour<ReadLinkFileResponse> {
	let path = remap_path!(path?);
	check_relative_paths!(path);

We first remap the path, then we check if the mapped path is relative. However in open (and some other hooks):

mirrord/mirrord/layer/src/file/ops.rs

Lines 205 to 210 in fd9ef90

	pub(crate) fn open(path: Detour<PathBuf>, open_options: OpenOptionsInternal) -> Detour<RawFd> {
	let path = path?;
	check_relative_paths!(path);
	let path = remap_path!(path);

If it's a relative path, we bypass before mapping the path.

We should make sure all detours have the same mapping logic.

The docs match the second case (ignore relative before mapping), so I assume this is the correct behaviour.

mirrord/mirrord/config/src/feature/fs/advanced.rs

Lines 135 to 136 in fd9ef90

	/// - Relative paths: this feature (currently) does not apply mappings to relative paths, e.g.
	/// `../dev`.

In most fs hooks, the three macros check_relative_paths!, remap_path! and ensure_not_ignored! should be called, so we should maybe just have a macro/function that calls them all in the right order.

[linear]

MBE-726 Different `feature.fs.mapping` behaviour in different hooks