Struct PathResolver 

pub(crate) struct PathResolver {
    root_dir: RootDir,
    root_dev: u64,
    root_ino: u64,
}

Resolves the symlinks in the parent (intermediate) components of a declared tmpfiles.d path against the physical rootfs, so that it matches what the /var walker in convert_path_to_tmpfiles_d_recurse actually encounters on disk.

For example, systemd’s provision.conf declares d /root/.ssh ..., but on a stateless/immutable-root system /root is a symlink to the physical /var/roothome, so the walker only ever sees /var/roothome/.ssh. Resolving /root/.ssh here to the identity of /var/roothome/.ssh lets a plain map lookup recognize it as covered, without the walker having to do a bidirectional alias lookup at every node.

The leaf (final) component of a path is never dereferenced, even if it happens to be a symlink itself: it’s the thing being declared by the tmpfiles.d line, may not exist yet, and its own target is irrelevant to resolving its location. Only the parent directory is ever opened.

Resolution of the parent is delegated entirely to the kernel via openat2(RESOLVE_IN_ROOT) (through [cap_std_ext::RootDir]), which correctly and safely handles arbitrary symlink chains, absolute symlink targets (chroot-style reinterpreted against the rootfs, e.g. a top-level /home -> /var/home), and symlink loops (surfaced as a standard ELOOP I/O error), without this crate needing to reimplement any of that itself.

Since the kernel has already done the real work of resolving the parent down to a live, open file descriptor, the result is reported as that descriptor’s (dev, ino) identity (via fstat). Querying identity directly on an already-open fd is kernel-authoritative and immune to concurrent path mutations (renames of ancestors, etc.).

If any component of the parent doesn’t exist, Ok(None) is returned: nothing can physically exist beneath a missing directory either, so the /var walker will never encounter (and thus never need to match) such a path in the first place.

Fields

root_dir: RootDir

root_dev: u64

The (dev, ino) identity of the rootfs root itself, captured once so that resolving a bare top-level entry (whose “parent” is the rootfs root, which can’t itself be a symlink) doesn’t need a separate lookup.

root_ino: u64

Implementations

impl PathResolver

pub(crate) fn new(rootfs: &Dir) -> Result<Self>

pub(crate) fn resolve_parent_identity( &self, path: &Path, ) -> Result<Option<PathIdentity>>

See the module-level docs on PathResolver for the full contract.