1 files changed, 156 insertions, 0 deletions
diff --git a/tests/matrix/statx_linux_test.go b/tests/matrix/statx_linux_test.go
new file mode 100644
index 0000000..4d62663
--- /dev/null
+++ b/tests/matrix/statx_linux_test.go
@@ -0,0 +1,156 @@
+package matrix
+
+import (
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"testing"
+	"time"
+
+	"golang.org/x/sys/unix"
+
+	"github.com/rfjakob/gocryptfs/v2/ctlsock"
+	"github.com/rfjakob/gocryptfs/v2/tests/test_helpers"
+)
+
+const testStatxMask = unix.STATX_BASIC_STATS | unix.STATX_BTIME
+
+func statxAt(t *testing.T, dirfd int, path string, flags int) unix.Statx_t {
+	t.Helper()
+	var st unix.Statx_t
+	if err := unix.Statx(dirfd, path, flags, testStatxMask, &st); err != nil {
+		t.Fatal(err)
+	}
+	return st
+}
+
+func encryptedPath(t *testing.T, plainPath string) string {
+	t.Helper()
+	resp := test_helpers.QueryCtlSock(t, ctlsockPath, ctlsock.RequestStruct{
+		EncryptPath: plainPath,
+	})
+	if resp.Result == "" {
+		t.Fatal(resp)
+	}
+	return filepath.Join(test_helpers.DefaultCipherDir, resp.Result)
+}
+
+func requireFuseStatx(t *testing.T) {
+	t.Helper()
+	data, err := os.ReadFile("/proc/sys/kernel/osrelease")
+	if err != nil {
+		t.Fatal(err)
+	}
+	parts := strings.SplitN(strings.TrimSpace(string(data)), ".", 3)
+	if len(parts) < 2 {
+		t.Skipf("cannot parse kernel release %q", data)
+	}
+	major, err := strconv.Atoi(parts[0])
+	if err != nil {
+		t.Skipf("cannot parse kernel release %q: %v", data, err)
+	}
+	minorString := parts[1]
+	if i := strings.IndexFunc(minorString, func(r rune) bool {
+		return r < '0' || r > '9'
+	}); i >= 0 {
+		minorString = minorString[:i]
+	}
+	minor, err := strconv.Atoi(minorString)
+	if err != nil {
+		t.Skipf("cannot parse kernel release %q: %v", data, err)
+	}
+	if major < 6 || major == 6 && minor < 6 {
+		t.Skip("FUSE_STATX requires Linux 6.6 or newer")
+	}
+}
+
+func checkBtime(t *testing.T, plainPath string, cipherPath string, flags int) unix.Statx_t {
+	t.Helper()
+	cipherSt := statxAt(t, unix.AT_FDCWD, cipherPath, flags)
+	if cipherSt.Mask&unix.STATX_BTIME == 0 {
+		t.Skip("backing filesystem does not report STATX_BTIME")
+	}
+	plainSt := statxAt(t, unix.AT_FDCWD, plainPath, flags)
+	if plainSt.Mask&unix.STATX_BTIME == 0 {
+		t.Fatalf("mounted filesystem did not report STATX_BTIME: mask=%#x", plainSt.Mask)
+	}
+	if plainSt.Btime.Sec != cipherSt.Btime.Sec || plainSt.Btime.Nsec != cipherSt.Btime.Nsec {
+		t.Errorf("birth time mismatch: plain=%d.%09d cipher=%d.%09d",
+			plainSt.Btime.Sec, plainSt.Btime.Nsec,
+			cipherSt.Btime.Sec, cipherSt.Btime.Nsec)
+	}
+	return plainSt
+}
+
+func TestStatxBtime(t *testing.T) {
+	requireFuseStatx(t)
+
+	t.Run("root", func(t *testing.T) {
+		checkBtime(t, test_helpers.DefaultPlainDir, test_helpers.DefaultCipherDir, unix.AT_SYMLINK_NOFOLLOW)
+	})
+
+	t.Run("regular", func(t *testing.T) {
+		const content = "statx birth time"
+		relPath := strings.ReplaceAll(t.Name(), "/", "_")
+		plainPath := filepath.Join(test_helpers.DefaultPlainDir, relPath)
+		if err := os.WriteFile(plainPath, []byte(content), 0600); err != nil {
+			t.Fatal(err)
+		}
+		cipherPath := encryptedPath(t, relPath)
+
+		before := checkBtime(t, plainPath, cipherPath, unix.AT_SYMLINK_NOFOLLOW)
+		if before.Size != uint64(len(content)) {
+			t.Errorf("wrong plaintext size: have=%d want=%d", before.Size, len(content))
+		}
+
+		// Check user-visible AT_EMPTY_PATH behavior. Current Linux kernels do
+		// not send the file handle in FUSE_STATX, so this still reaches
+		// Node.Statx rather than File.Statx.
+		f, err := os.Open(plainPath)
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer f.Close()
+		fdSt := statxAt(t, int(f.Fd()), "", unix.AT_EMPTY_PATH)
+		if fdSt.Mask&unix.STATX_BTIME == 0 {
+			t.Fatalf("statx on open file did not report STATX_BTIME: mask=%#x", fdSt.Mask)
+		}
+		if fdSt.Btime.Sec != before.Btime.Sec || fdSt.Btime.Nsec != before.Btime.Nsec {
+			t.Errorf("statx on open file returned different birth time: path=%d.%09d fd=%d.%09d",
+				before.Btime.Sec, before.Btime.Nsec, fdSt.Btime.Sec, fdSt.Btime.Nsec)
+		}
+
+		now := time.Now().Add(-time.Hour)
+		if err := os.Chtimes(plainPath, now, now); err != nil {
+			t.Fatal(err)
+		}
+		after := checkBtime(t, plainPath, cipherPath, unix.AT_SYMLINK_NOFOLLOW)
+		if after.Btime.Sec != before.Btime.Sec || after.Btime.Nsec != before.Btime.Nsec {
+			t.Errorf("birth time changed with mtime: before=%d.%09d after=%d.%09d",
+				before.Btime.Sec, before.Btime.Nsec, after.Btime.Sec, after.Btime.Nsec)
+		}
+	})
+
+	t.Run("directory", func(t *testing.T) {
+		relPath := strings.ReplaceAll(t.Name(), "/", "_")
+		plainPath := filepath.Join(test_helpers.DefaultPlainDir, relPath)
+		if err := os.Mkdir(plainPath, 0700); err != nil {
+			t.Fatal(err)
+		}
+		checkBtime(t, plainPath, encryptedPath(t, relPath), unix.AT_SYMLINK_NOFOLLOW)
+	})
+
+	t.Run("symlink", func(t *testing.T) {
+		const target = "/target/does/not/exist"
+		relPath := strings.ReplaceAll(t.Name(), "/", "_")
+		plainPath := filepath.Join(test_helpers.DefaultPlainDir, relPath)
+		if err := os.Symlink(target, plainPath); err != nil {
+			t.Fatal(err)
+		}
+		st := checkBtime(t, plainPath, encryptedPath(t, relPath), unix.AT_SYMLINK_NOFOLLOW)
+		if st.Size != uint64(len(target)) {
+			t.Errorf("wrong symlink size: have=%d want=%d", st.Size, len(target))
+		}
+	})
+}