FDS/OS 1.0

tools/rootfs_lib.py

@@ -0,0 +1,42 @@
+"""Shared host-side inspection of FDS root filesystems (standard library only)."""
+import hashlib
+import pathlib
+import plistlib
+
+
+def package_db(root):
+    with (root / "var/db/xbps/pkgdb-0.38.plist").open("rb") as stream:
+        db = plistlib.load(stream)
+    return {name: props for name, props in db.items() if not name.startswith("_")}
+
+
+def rooted(root, name):
+    """Resolve guest symlinks inside root, including absolute links, never on host."""
+    todo = list(pathlib.PurePosixPath(name).parts)
+    parts = []
+    links = 0
+    while todo:
+        part = todo.pop(0)
+        if part in ("/", "."):
+            continue
+        if part == "..":
+            if parts:
+                parts.pop()
+            continue
+        candidate = root.joinpath(*parts, part)
+        if candidate.is_symlink():
+            links += 1
+            if links > 40:
+                raise ValueError(f"Symlink loop: {name}")
+            target = candidate.readlink()
+            if target.is_absolute():
+                parts = []
+            todo = list(target.parts) + todo
+        else:
+            parts.append(part)
+    return root.joinpath(*parts)
+
+
+def digest(path):
+    with path.open("rb") as stream:
+        return hashlib.file_digest(stream, "sha256").hexdigest()