Fuzz btrfsitem, and by consequence improve binstruct errors

1 files changed, 65 insertions, 0 deletions

diff --git a/lib/btrfs/btrfsitem/items_test.go b/lib/btrfs/btrfsitem/items_test.go
new file mode 100644
index 0000000..aba8ca2
--- /dev/null
+++ b/lib/btrfs/btrfsitem/items_test.go
@@ -0,0 +1,65 @@
+// Copyright (C) 2022  Luke Shumaker <lukeshu@lukeshu.com>
+//
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+package btrfsitem_test
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+
+	"git.lukeshu.com/btrfs-progs-ng/lib/binstruct"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfsitem"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/btrfssum"
+	"git.lukeshu.com/btrfs-progs-ng/lib/btrfs/internal"
+)
+
+func FuzzRoundTrip(f *testing.F) {
+	keySize := binstruct.StaticSize(internal.Key{})
+	sumtypeSize := binstruct.StaticSize(btrfssum.CSumType(0))
+
+	f.Add(make([]byte, 256))
+
+	f.Fuzz(func(t *testing.T, inDat []byte) {
+		if len(inDat) < keySize+sumtypeSize {
+			t.Skip()
+		}
+		keyInDat, inDat := inDat[:keySize], inDat[keySize:]
+		sumtypeInDat, inDat := inDat[:sumtypeSize], inDat[sumtypeSize:]
+		itemInDat := inDat
+
+		// key
+
+		var key internal.Key
+		n, err := binstruct.Unmarshal(keyInDat, &key)
+		require.NoError(t, err, "binstruct.Unmarshal(dat, &key)")
+		require.Equal(t, keySize, n, "binstruct.Unmarshal(dat, &key)")
+
+		keyOutDat, err := binstruct.Marshal(key)
+		require.NoError(t, err, "binstruct.Marshal(key)")
+		require.Equal(t, keyInDat, keyOutDat, "binstruct.Marshal(key)")
+
+		// sumtype
+
+		var sumtype btrfssum.CSumType
+		n, err = binstruct.Unmarshal(sumtypeInDat, &sumtype)
+		require.NoError(t, err, "binstruct.Unmarshal(dat, &sumtype)")
+		require.Equal(t, sumtypeSize, n, "binstruct.Unmarshal(dat, &sumtype)")
+
+		sumtypeOutDat, err := binstruct.Marshal(sumtype)
+		require.NoError(t, err, "binstruct.Marshal(sumtype)")
+		require.Equal(t, sumtypeInDat, sumtypeOutDat, "binstruct.Marshal(sumtype)")
+
+		// item
+
+		t.Logf("key=%v sumtype=%v dat=%q", key, sumtype, itemInDat)
+
+		item := btrfsitem.UnmarshalItem(key, sumtype, itemInDat)
+		require.NotNil(t, item, "btrfsitem.UnmarshalItem")
+
+		itemOutDat, err := binstruct.Marshal(item)
+		require.NoError(t, err, "binstruct.Marshal(item)")
+		require.Equal(t, string(itemInDat), string(itemOutDat), "binstruct.Marshal(item)")
+	})
+}