tests: Add append test

main_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"bytes"
 	"crypto/md5"
 	"encoding/hex"
 	"fmt"
@@ -145,6 +146,38 @@ func TestTruncate(t *testing.T) {
 	}
 }
 
+func TestAppend(t *testing.T) {
+	fn := plainDir + "append"
+	file, err := os.Create(fn)
+	if err != nil {
+		t.FailNow()
+	}
+	data := []byte("testdata123456789") // length 17
+	var buf bytes.Buffer
+	var hashWant string
+	for i := 0; i <= 500; i++ {
+		file.Write(data)
+		buf.Write(data)
+		bin := md5.Sum(buf.Bytes())
+		hashWant = hex.EncodeToString(bin[:])
+		hashActual := md5fn(fn)
+		if hashWant != hashActual {
+			t.FailNow()
+		}
+	}
+
+	// Overwrite with the same data
+	// Hash must stay the same
+	file.Seek(0, 0)
+	for i := 0; i <= 500; i++ {
+		file.Write(data)
+		hashActual := md5fn(fn)
+		if hashWant != hashActual {
+			t.FailNow()
+		}
+	}
+}
+
 func BenchmarkStreamWrite(t *testing.B) {
 	buf := make([]byte, 1024*1024)
 	t.SetBytes(int64(len(buf)))

pathfs_frontend/file.go

@@ -70,11 +70,12 @@ func (f *file) doRead(off uint64, length uint64) ([]byte, fuse.Status) {
 		cryptfs.Warn.Printf("read: ReadAt: %s\n", err.Error())
 		return nil, fuse.ToStatus(err)
 	}
-	cryptfs.Debug.Printf("ReadAt length=%d offset=%d -> n=%d len=%d\n", alignedLength, alignedOffset, n, len(ciphertext))
+	cryptfs.Debug.Printf("ReadAt offset=%d length=%d -> n=%d len=%d\n", alignedLength, alignedOffset, n, len(ciphertext))
 
 	// Decrypt it
 	plaintext, err := f.cfs.DecryptBlocks(ciphertext)
 	if err != nil {
+		cryptfs.Warn.Printf("Corrupt block at offset=%d\n", off + uint64(len(plaintext)))
 		cryptfs.Warn.Printf("doRead: returning IO error\n")
 		return nil, fuse.EIO
 	}