func (bdr *Reader) Read(p []byte) (int, error) {
nr := util.IntMin(len(p), bdr.lenTotal-bdr.lenRead)
left := p[:nr]
if nr == 0 {
return 0, io.EOF
}
n := 0
for len(left) > 0 {
if len(bdr.unread) == 0 {
if err := bdr.decryptNextFrame(); err != nil {
return n, err
}
}
if len(bdr.unread) == 0 {
panic("decryptNextFrame should have decrypted something and placed it on the buf")
}
consumeLen := util.IntMin(len(bdr.unread), len(left))
copy(left[:consumeLen], bdr.unread[:consumeLen])
bdr.unread = bdr.unread[consumeLen:]
left = left[consumeLen:]
n += consumeLen
bdr.lenRead += consumeLen
}
return n, nil
}
func (bew *WriteCloser) Write(p []byte) (int, error) {
if len(p) == 0 {
return 0, nil
}
left := p
for len(left) > 0 {
framePayloadLen := util.IntMin(bew.frameEncryptor.CapacityLeft(), len(left))
framePayload := left[:framePayloadLen]
if _, err := bew.frameEncryptor.Write(framePayload); err != nil {
panic(err)
}
left = left[framePayloadLen:]
bew.lenWritten += framePayloadLen
if bew.frameEncryptor.CapacityLeft() == 0 {
if err := bew.flushFrame(); err != nil {
return 0, err
}
}
if bew.frameEncryptor.CapacityLeft() == 0 {
panic("flushFrame should have brought back capacity")
}
}
return len(p), nil
}
func (bdr *Reader) decryptNextFrame() error {
frameLen := util.IntMin(bdr.lenTotal-bdr.lenRead, BtnFrameMaxPayload)
encryptedFrameLen := bdr.c.EncryptedFrameSize(frameLen)
// fmt.Printf("frameLen: %d, encryptedFrameLen: %d\n", frameLen, encryptedFrameLen)
bdr.encrypted = bdr.encrypted[:encryptedFrameLen]
if _, err := io.ReadFull(bdr.src, bdr.encrypted); err != nil {
return err
}
nonceSize := bdr.c.gcm.NonceSize()
nonce := bdr.encrypted[:nonceSize]
ciphertext := bdr.encrypted[nonceSize:]
var err error
bdr.decrypted = bdr.decrypted[:0]
if bdr.decrypted, err = bdr.c.gcm.Open(bdr.decrypted, nonce, ciphertext, nil); err != nil {
return err
}
bdr.unread = bdr.decrypted
return nil
}
func (ch *ChunkIO) PWrite(offset int64, p []byte) error {
log.Printf("PWrite: offset %d, len %d", offset, len(p))
// log.Printf("PWrite: p=%v", p)
if err := ch.ensureHeader(); err != nil {
return err
}
if len(p) == 0 {
return nil
}
if offset < 0 || math.MaxInt32 < offset {
return fmt.Errorf("Offset out of range: %d", offset)
}
remo := int(offset)
remp := p
if remo > ch.PayloadLen() {
// if expanding, zero fill content frames up to write offset
zfoff := ch.PayloadLen()
zflen := remo - ch.PayloadLen()
for zflen > 0 {
log.Printf("PWrite zfoff: %d, zflen: %d", zfoff, zflen)
i := zfoff / ContentFramePayloadLength
fOffset := i * ContentFramePayloadLength
var f *decryptedContentFrame
inframeOffset := zfoff - fOffset
if zfoff == ch.PayloadLen() && inframeOffset == 0 {
log.Printf("PWrite: write new zero fill frame")
// FIXME: maybe skip writing pure 0 frame.
// Old sambad writes a byte of the end of the file instead of ftruncate, which is a nightmare in the current impl.
n := util.IntMin(zflen, ContentFramePayloadLength)
f = &decryptedContentFrame{
P: ZeroContent[:n],
Offset: fOffset,
IsLastFrame: false,
}
zfoff += n
zflen -= n
ch.expandLengthBy(n)
log.Printf(" len: %d", n)
} else {
n := util.IntMin(zflen, ContentFramePayloadLength-inframeOffset)
log.Printf("PWrite: zero fill last of existing content frame. len: %d f.P[%d:%d] = 0", n, inframeOffset, inframeOffset+n)
// read the frame
var err error
f, err = ch.readContentFrame(i)
if err != nil {
return err
}
if fOffset != f.Offset {
panic("fOffset != f.Offset")
}
// expand & zero fill
f.P = f.P[:inframeOffset+n]
j := 0
for j < n {
f.P[inframeOffset+j] = 0
j++
}
zfoff += n
zflen -= n
ch.expandLengthBy(n)
}
// writeback the frame
if err := ch.writeContentFrame(i, f); err != nil {
return fmt.Errorf("failed to write back the encrypted frame: %v", err)
}
}
}
for len(remp) > 0 {
i := remo / ContentFramePayloadLength
fOffset := i * ContentFramePayloadLength
var f *decryptedContentFrame
if remo == ch.PayloadLen() && fOffset == remo {
log.Printf("PWrite: Preparing new frame to append")
f = &decryptedContentFrame{
P: make([]byte, 0, ContentFramePayloadLength),
Offset: fOffset,
IsLastFrame: true,
}
} else {
log.Printf("PWrite: Read existing frame %d to append/update", i)
var err error
f, err = ch.readContentFrame(i)
if err != nil {
return err
}
if fOffset != f.Offset {
panic("fOffset != f.Offset")
}
}
// modify the payload
inframeOffset := remo - f.Offset
if inframeOffset < 0 {
panic("ASSERT: inframeOffset must be non-negative here")
}
n := len(remp)
valid := len(f.P) - inframeOffset // valid payload after offset
if len(remp) > valid && f.IsLastFrame {
// expand the last frame as needed
newSize := inframeOffset + n
if newSize > ContentFramePayloadLength {
f.IsLastFrame = false
newSize = ContentFramePayloadLength
}
log.Printf("PWrite: Expanding the last frame from %d to %d", len(f.P), newSize)
expandLen := newSize - len(f.P)
if err := ch.expandLengthBy(expandLen); err != nil {
return err
}
f.P = f.P[:newSize]
valid = newSize - inframeOffset
}
if valid == 0 {
panic("Inf loop")
}
n = util.IntMin(n, valid)
copy(f.P[inframeOffset:inframeOffset+n], remp)
// writeback the updated encrypted frame
if err := ch.writeContentFrame(i, f); err != nil {
return fmt.Errorf("failed to write back the encrypted frame: %v", err)
}
log.Printf("PWrite: wrote %d bytes for off %d len %d", n, offset, len(remp))
remo += n
remp = remp[n:]
}
return nil
}
func (cfio *ChunkedFileIO) PWrite(p []byte, offset int64) error {
logger.Debugf(mylog, "PWrite: offset=%d, len=%d", offset, len(p))
// logger.Debugf(mylog, "PWrite: p=%v", p)
remo := offset
remp := p
if len(remp) == 0 {
return nil
}
cs, err := cfio.caio.Read()
if err != nil {
return fmt.Errorf("Failed to read cs array: %v", err)
}
writeToChunk := func(c *inodedb.FileChunk, isNewChunk bool, maxChunkLen int64) error {
if !fl.IsReadWriteAllowed(cfio.bs.Flags()) {
return EPERM
}
flags := fl.O_RDWR
if isNewChunk {
flags |= fl.O_CREATE | fl.O_EXCL
}
bh, err := cfio.bs.Open(c.BlobPath, flags)
if err != nil {
return fmt.Errorf("Failed to open path \"%s\" for writing (isNewChunk: %t): %v", c.BlobPath, isNewChunk, err)
}
defer func() {
if err := bh.Close(); err != nil {
logger.Criticalf(mylog, "blobhandle Close failed: %v", err)
}
}()
cio := cfio.newChunkIO(bh, cfio.c, c.Offset)
defer func() {
if err := cio.Close(); err != nil {
logger.Criticalf(mylog, "cio Close failed: %v", err)
}
}()
coff := remo - c.Offset
n := util.IntMin(len(remp), int(maxChunkLen-coff))
if n < 0 {
return nil
}
if err := cio.PWrite(remp[:n], coff); err != nil {
return err
}
oldLength := c.Length
c.Length = int64(cio.Size())
if oldLength != c.Length {
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
}
remo += int64(n)
remp = remp[n:]
return nil
}
for i := 0; i < len(cs); i++ {
c := &cs[i]
if c.Left() > remo {
// Insert a new chunk @ i
// try best to align offset at ChunkSplitSize
newo := remo / ChunkSplitSize * ChunkSplitSize
maxlen := int64(ChunkSplitSize)
if i > 0 {
prev := cs[i-1]
pright := prev.Right()
if newo < pright {
maxlen -= pright - newo
newo = pright
}
}
if i < len(cs)-1 {
next := cs[i+1]
if newo+maxlen > next.Left() {
maxlen = next.Left() - newo
}
}
newc, err := cfio.newFileChunk(newo)
if err != nil {
return err
}
cs = append(cs, inodedb.FileChunk{})
copy(cs[i+1:], cs[i:])
cs[i] = newc
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
if err := writeToChunk(&newc, NewChunk, maxlen); err != nil {
return err
}
if len(remp) == 0 {
break
}
continue
}
// Write to the chunk
maxlen := int64(ChunkSplitSize)
if i < len(cs)-1 {
next := cs[i+1]
if c.Left()+maxlen > next.Left() {
maxlen = next.Left() - c.Left()
}
}
if err := writeToChunk(c, ExistingChunk, maxlen); err != nil {
return err
}
if len(remp) == 0 {
break
}
}
for len(remp) > 0 {
// Append a new chunk at the end
newo := remo / ChunkSplitSize * ChunkSplitSize
maxlen := int64(ChunkSplitSize)
if len(cs) > 0 {
last := cs[len(cs)-1]
lastRight := last.Right()
if newo < lastRight {
maxlen -= lastRight - newo
newo = lastRight
}
}
newc, err := cfio.newFileChunk(newo)
if err != nil {
return err
}
if err := writeToChunk(&newc, NewChunk, maxlen); err != nil {
return err
}
cs = append(cs, newc)
if err := cfio.caio.Write(cs); err != nil {
return fmt.Errorf("Failed to write updated cs array: %v", err)
}
}
return nil
}
func (wc *FileWriteCache) ReadAtThrough(p []byte, offset int64, r ReadAter) (int, error) {
nr := 0
remo := offset
remp := p
for _, patch := range wc.ps {
if len(remp) == 0 {
return nr, nil
}
if patch.IsSentinel() {
break
}
if remo > patch.Right() {
continue
}
if remo < patch.Left() {
fallbackLen64 := util.Int64Min(int64(len(remp)), patch.Left()-remo)
if fallbackLen64 > math.MaxInt32 {
panic("Logic error: fallbackLen should always be in int32 range")
}
fallbackLen := int(fallbackLen64)
n, err := r.ReadAt(remp[:fallbackLen], remo)
logger.Debugf(wclog, "BeforePatch: ReadAt issued offset %d, len %d bytes, read %d bytes", remo, fallbackLen, n)
if err != nil {
return nr + n, err
}
if n < fallbackLen {
zerofill(remp[n:fallbackLen])
}
nr += fallbackLen
remp = remp[fallbackLen:]
remo += int64(fallbackLen)
}
if len(remp) == 0 {
return nr, nil
}
applyOffset64 := remo - patch.Offset
if applyOffset64 > math.MaxInt32 {
panic("Logic error: applyOffset should always be in int32 range")
}
applyOffset := int(applyOffset64)
applyLen := util.IntMin(len(patch.P)-applyOffset, len(remp))
copy(remp[:applyLen], patch.P[applyOffset:])
nr += applyLen
remp = remp[applyLen:]
remo += int64(applyLen)
}
n, err := r.ReadAt(remp, remo)
logger.Debugf(wclog, "Last: ReadAt read %d bytes", n)
if err != nil {
return nr, err
}
nr += n
return nr, nil
}
