fix: list hardlink alternate paths in holds

src/wholocks/_linux.py

@@ -194,7 +194,7 @@ def add(label):
             continue
 
         name, cmdline, user = _proc_identity(pid_dir)
-        matched_paths = _matched_paths_for(pid_dir, match)
+        matched_paths = _matched_paths_for(pid_dir, match, target_inodes)
         holders.append(
             Holder(
                 pid=pid,
@@ -223,9 +223,10 @@ def add(label):
     )
 
 
-def _matched_paths_for(pid_dir, match):
+def _matched_paths_for(pid_dir, match, target_inodes=None):
     """Collect the concrete paths this process holds (for display)."""
     found = []
+    target_inodes = target_inodes or set()
 
     def note(path):
         if path and path not in found:
@@ -249,4 +250,12 @@ def note(path):
         target, _ = _strip_deleted(target)
         if match(target):
             note(target)
+            continue
+        if target_inodes and target.startswith("/"):
+            try:
+                st = os.stat(os.path.join(fd_dir, fd))
+            except OSError:
+                continue
+            if (st.st_dev, st.st_ino) in target_inodes:
+                note(target)
     return found

tests/test_hardlink_paths.py

@@ -0,0 +1,49 @@
+"""Linux hardlink holders should list the alternate path in holds:."""
+
+import os
+import sys
+
+import pytest
+
+pytestmark = pytest.mark.skipif(
+    sys.platform.startswith("win"), reason="requires POSIX hardlinks"
+)
+
+
+@pytest.fixture
+def fake_proc(tmp_path, monkeypatch):
+    import wholocks._linux as _linux
+
+    proc = tmp_path / "proc"
+    proc.mkdir()
+    (proc / "stat").write_text("cpu 1 2 3\nbtime 1700000000\n")
+    monkeypatch.setattr(_linux, "PROC_ROOT", str(proc))
+    return proc
+
+
+def _make_pid(proc_dir, pid, comm="logger"):
+    d = proc_dir / str(pid)
+    d.mkdir()
+    (d / "comm").write_text(comm + "\n")
+    (d / "cmdline").write_bytes(b"logger\0")
+    (d / "stat").write_text("%d (%s) S 1 1 1 0 -1 4194304 0 0 0 0 0 0 0 0 20 0 1 0 777 100\n" % (pid, comm))
+    (d / "maps").write_text("")
+    (d / "fd").mkdir()
+    return d
+
+
+def test_hardlink_fd_lists_alternate_path(fake_proc, tmp_path):
+    import wholocks._linux as _linux
+
+    target = tmp_path / "canonical.log"
+    target.write_text("data")
+    alias = tmp_path / "rotated.log"
+    os.link(target, alias)
+
+    pid_dir = _make_pid(fake_proc, 9100)
+    os.symlink(os.path.realpath(str(alias)), pid_dir / "fd" / "3")
+
+    result = _linux.scan([str(target)], [], recursive=False)
+    assert len(result.holders) == 1
+    assert "hardlink" in result.holders[0].access[0]
+    assert os.path.realpath(str(alias)) in result.holders[0].paths