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Diffstat (limited to 'pathfs_frontend/file.go')
-rw-r--r--pathfs_frontend/file.go501
1 files changed, 0 insertions, 501 deletions
diff --git a/pathfs_frontend/file.go b/pathfs_frontend/file.go
deleted file mode 100644
index 387eb35..0000000
--- a/pathfs_frontend/file.go
+++ /dev/null
@@ -1,501 +0,0 @@
-package pathfs_frontend
-
-// FUSE operations on file handles
-
-import (
- "bytes"
- "fmt"
- "io"
- "os"
- "sync"
- "syscall"
- "time"
-
- "github.com/hanwen/go-fuse/fuse"
- "github.com/hanwen/go-fuse/fuse/nodefs"
-
- "github.com/rfjakob/gocryptfs/internal/contentenc"
- "github.com/rfjakob/gocryptfs/internal/toggledlog"
-)
-
-// File - based on loopbackFile in go-fuse/fuse/nodefs/files.go
-type file struct {
- fd *os.File
-
- // fdLock prevents the fd to be closed while we are in the middle of
- // an operation.
- // Every FUSE entrypoint should RLock(). The only user of Lock() is
- // Release(), which closes the fd, hence has to acquire an exclusive lock.
- fdLock sync.RWMutex
-
- // Was the file opened O_WRONLY?
- writeOnly bool
-
- // Content encryption helper
- contentEnc *contentenc.ContentEnc
-
- // Inode number
- ino uint64
-
- // File header
- header *contentenc.FileHeader
-
- forgotten bool
-}
-
-func NewFile(fd *os.File, writeOnly bool, contentEnc *contentenc.ContentEnc) nodefs.File {
- var st syscall.Stat_t
- syscall.Fstat(int(fd.Fd()), &st)
- wlock.register(st.Ino)
-
- return &file{
- fd: fd,
- writeOnly: writeOnly,
- contentEnc: contentEnc,
- ino: st.Ino,
- }
-}
-
-// intFd - return the backing file descriptor as an integer. Used for debug
-// messages.
-func (f *file) intFd() int {
- return int(f.fd.Fd())
-}
-
-func (f *file) InnerFile() nodefs.File {
- return nil
-}
-
-func (f *file) SetInode(n *nodefs.Inode) {
-}
-
-// readHeader - load the file header from disk
-//
-// Returns io.EOF if the file is empty
-func (f *file) readHeader() error {
- buf := make([]byte, contentenc.HEADER_LEN)
- _, err := f.fd.ReadAt(buf, 0)
- if err != nil {
- return err
- }
- h, err := contentenc.ParseHeader(buf)
- if err != nil {
- return err
- }
- f.header = h
-
- return nil
-}
-
-// createHeader - create a new random header and write it to disk
-func (f *file) createHeader() error {
- h := contentenc.RandomHeader()
- buf := h.Pack()
-
- // Prevent partially written (=corrupt) header by preallocating the space beforehand
- err := prealloc(int(f.fd.Fd()), 0, contentenc.HEADER_LEN)
- if err != nil {
- toggledlog.Warn.Printf("ino%d: createHeader: prealloc failed: %s\n", f.ino, err.Error())
- return err
- }
-
- // Actually write header
- _, err = f.fd.WriteAt(buf, 0)
- if err != nil {
- return err
- }
- f.header = h
-
- return nil
-}
-
-func (f *file) String() string {
- return fmt.Sprintf("cryptFile(%s)", f.fd.Name())
-}
-
-// doRead - returns "length" plaintext bytes from plaintext offset "off".
-// Arguments "length" and "off" do not have to be block-aligned.
-//
-// doRead reads the corresponding ciphertext blocks from disk, decrypts them and
-// returns the requested part of the plaintext.
-//
-// Called by Read() for normal reading,
-// by Write() and Truncate() for Read-Modify-Write
-func (f *file) doRead(off uint64, length uint64) ([]byte, fuse.Status) {
-
- // Read file header
- if f.header == nil {
- err := f.readHeader()
- if err == io.EOF {
- return nil, fuse.OK
- }
- if err != nil {
- return nil, fuse.ToStatus(err)
- }
- }
-
- // Read the backing ciphertext in one go
- blocks := f.contentEnc.ExplodePlainRange(off, length)
- alignedOffset, alignedLength := blocks[0].JointCiphertextRange(blocks)
- skip := blocks[0].Skip
- toggledlog.Debug.Printf("JointCiphertextRange(%d, %d) -> %d, %d, %d", off, length, alignedOffset, alignedLength, skip)
- ciphertext := make([]byte, int(alignedLength))
- n, err := f.fd.ReadAt(ciphertext, int64(alignedOffset))
- if err != nil && err != io.EOF {
- toggledlog.Warn.Printf("read: ReadAt: %s", err.Error())
- return nil, fuse.ToStatus(err)
- }
- // Truncate ciphertext buffer down to actually read bytes
- ciphertext = ciphertext[0:n]
-
- firstBlockNo := blocks[0].BlockNo
- toggledlog.Debug.Printf("ReadAt offset=%d bytes (%d blocks), want=%d, got=%d", alignedOffset, firstBlockNo, alignedLength, n)
-
- // Decrypt it
- plaintext, err := f.contentEnc.DecryptBlocks(ciphertext, firstBlockNo, f.header.Id)
- if err != nil {
- curruptBlockNo := firstBlockNo + f.contentEnc.PlainOffToBlockNo(uint64(len(plaintext)))
- cipherOff := f.contentEnc.BlockNoToCipherOff(curruptBlockNo)
- plainOff := f.contentEnc.BlockNoToPlainOff(curruptBlockNo)
- toggledlog.Warn.Printf("ino%d: doRead: corrupt block #%d (plainOff=%d, cipherOff=%d)",
- f.ino, curruptBlockNo, plainOff, cipherOff)
- return nil, fuse.EIO
- }
-
- // Crop down to the relevant part
- var out []byte
- lenHave := len(plaintext)
- lenWant := int(skip + length)
- if lenHave > lenWant {
- out = plaintext[skip:lenWant]
- } else if lenHave > int(skip) {
- out = plaintext[skip:lenHave]
- }
- // else: out stays empty, file was smaller than the requested offset
-
- return out, fuse.OK
-}
-
-// Read - FUSE call
-func (f *file) Read(buf []byte, off int64) (resultData fuse.ReadResult, code fuse.Status) {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- toggledlog.Debug.Printf("ino%d: FUSE Read: offset=%d length=%d", f.ino, len(buf), off)
-
- if f.writeOnly {
- toggledlog.Warn.Printf("ino%d: Tried to read from write-only file", f.ino)
- return nil, fuse.EBADF
- }
-
- out, status := f.doRead(uint64(off), uint64(len(buf)))
-
- if status == fuse.EIO {
- toggledlog.Warn.Printf("ino%d: Read failed with EIO, offset=%d, length=%d", f.ino, len(buf), off)
- }
- if status != fuse.OK {
- return nil, status
- }
-
- toggledlog.Debug.Printf("ino%d: Read: status %v, returning %d bytes", f.ino, status, len(out))
- return fuse.ReadResultData(out), status
-}
-
-const FALLOC_FL_KEEP_SIZE = 0x01
-
-// doWrite - encrypt "data" and write it to plaintext offset "off"
-//
-// Arguments do not have to be block-aligned, read-modify-write is
-// performed internally as neccessary
-//
-// Called by Write() for normal writing,
-// and by Truncate() to rewrite the last file block.
-func (f *file) doWrite(data []byte, off int64) (uint32, fuse.Status) {
-
- // Read header from disk, create a new one if the file is empty
- if f.header == nil {
- err := f.readHeader()
- if err == io.EOF {
- err = f.createHeader()
-
- }
- if err != nil {
- return 0, fuse.ToStatus(err)
- }
- }
-
- var written uint32
- status := fuse.OK
- dataBuf := bytes.NewBuffer(data)
- blocks := f.contentEnc.ExplodePlainRange(uint64(off), uint64(len(data)))
- for _, b := range blocks {
-
- blockData := dataBuf.Next(int(b.Length))
-
- // Incomplete block -> Read-Modify-Write
- if b.IsPartial() {
- // Read
- o, _ := b.PlaintextRange()
- oldData, status := f.doRead(o, f.contentEnc.PlainBS())
- if status != fuse.OK {
- toggledlog.Warn.Printf("ino%d fh%d: RMW read failed: %s", f.ino, f.intFd(), status.String())
- return written, status
- }
- // Modify
- blockData = f.contentEnc.MergeBlocks(oldData, blockData, int(b.Skip))
- toggledlog.Debug.Printf("len(oldData)=%d len(blockData)=%d", len(oldData), len(blockData))
- }
-
- // Encrypt
- blockOffset, blockLen := b.CiphertextRange()
- blockData = f.contentEnc.EncryptBlock(blockData, b.BlockNo, f.header.Id)
- toggledlog.Debug.Printf("ino%d: Writing %d bytes to block #%d",
- f.ino, uint64(len(blockData))-f.contentEnc.BlockOverhead(), b.BlockNo)
-
- // Prevent partially written (=corrupt) blocks by preallocating the space beforehand
- err := prealloc(int(f.fd.Fd()), int64(blockOffset), int64(blockLen))
- if err != nil {
- toggledlog.Warn.Printf("ino%d fh%d: doWrite: prealloc failed: %s", f.ino, f.intFd(), err.Error())
- status = fuse.ToStatus(err)
- break
- }
-
- // Write
- _, err = f.fd.WriteAt(blockData, int64(blockOffset))
-
- if err != nil {
- toggledlog.Warn.Printf("doWrite: Write failed: %s", err.Error())
- status = fuse.ToStatus(err)
- break
- }
- written += uint32(b.Length)
- }
- return written, status
-}
-
-// Write - FUSE call
-func (f *file) Write(data []byte, off int64) (uint32, fuse.Status) {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
- wlock.lock(f.ino)
- defer wlock.unlock(f.ino)
-
- toggledlog.Debug.Printf("ino%d: FUSE Write: offset=%d length=%d", f.ino, off, len(data))
-
- fi, err := f.fd.Stat()
- if err != nil {
- toggledlog.Warn.Printf("Write: Fstat failed: %v", err)
- return 0, fuse.ToStatus(err)
- }
- plainSize := f.contentEnc.CipherSizeToPlainSize(uint64(fi.Size()))
- if f.createsHole(plainSize, off) {
- status := f.zeroPad(plainSize)
- if status != fuse.OK {
- toggledlog.Warn.Printf("zeroPad returned error %v", status)
- return 0, status
- }
- }
- return f.doWrite(data, off)
-}
-
-// Release - FUSE call, close file
-func (f *file) Release() {
- f.fdLock.Lock()
- defer f.fdLock.Unlock()
-
- f.fd.Close()
- f.forgotten = true
-}
-
-// Flush - FUSE call
-func (f *file) Flush() fuse.Status {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- // Since Flush() may be called for each dup'd fd, we don't
- // want to really close the file, we just want to flush. This
- // is achieved by closing a dup'd fd.
- newFd, err := syscall.Dup(int(f.fd.Fd()))
-
- if err != nil {
- return fuse.ToStatus(err)
- }
- err = syscall.Close(newFd)
- return fuse.ToStatus(err)
-}
-
-func (f *file) Fsync(flags int) (code fuse.Status) {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- return fuse.ToStatus(syscall.Fsync(int(f.fd.Fd())))
-}
-
-// Truncate - FUSE call
-func (f *file) Truncate(newSize uint64) fuse.Status {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
- wlock.lock(f.ino)
- defer wlock.unlock(f.ino)
-
- if f.forgotten {
- toggledlog.Warn.Printf("ino%d fh%d: Truncate on forgotten file", f.ino, f.intFd())
- }
-
- // Common case first: Truncate to zero
- if newSize == 0 {
- err := syscall.Ftruncate(int(f.fd.Fd()), 0)
- if err != nil {
- toggledlog.Warn.Printf("ino%d fh%d: Ftruncate(fd, 0) returned error: %v", f.ino, f.intFd(), err)
- return fuse.ToStatus(err)
- }
- // Truncate to zero kills the file header
- f.header = nil
- return fuse.OK
- }
-
- // We need the old file size to determine if we are growing or shrinking
- // the file
- fi, err := f.fd.Stat()
- if err != nil {
- toggledlog.Warn.Printf("ino%d fh%d: Truncate: Fstat failed: %v", f.ino, f.intFd(), err)
- return fuse.ToStatus(err)
- }
- oldSize := f.contentEnc.CipherSizeToPlainSize(uint64(fi.Size()))
- {
- oldB := float32(oldSize) / float32(f.contentEnc.PlainBS())
- newB := float32(newSize) / float32(f.contentEnc.PlainBS())
- toggledlog.Debug.Printf("ino%d: FUSE Truncate from %.2f to %.2f blocks (%d to %d bytes)", f.ino, oldB, newB, oldSize, newSize)
- }
-
- // File size stays the same - nothing to do
- if newSize == oldSize {
- return fuse.OK
- }
-
- // File grows
- if newSize > oldSize {
-
- // File was empty, create new header
- if oldSize == 0 {
- err := f.createHeader()
- if err != nil {
- return fuse.ToStatus(err)
- }
- }
-
- blocks := f.contentEnc.ExplodePlainRange(oldSize, newSize-oldSize)
- for _, b := range blocks {
- // First and last block may be partial
- if b.IsPartial() {
- off, _ := b.PlaintextRange()
- off += b.Skip
- _, status := f.doWrite(make([]byte, b.Length), int64(off))
- if status != fuse.OK {
- return status
- }
- } else {
- off, length := b.CiphertextRange()
- err := syscall.Ftruncate(int(f.fd.Fd()), int64(off+length))
- if err != nil {
- toggledlog.Warn.Printf("grow Ftruncate returned error: %v", err)
- return fuse.ToStatus(err)
- }
- }
- }
- return fuse.OK
- } else {
- // File shrinks
- blockNo := f.contentEnc.PlainOffToBlockNo(newSize)
- cipherOff := f.contentEnc.BlockNoToCipherOff(blockNo)
- plainOff := f.contentEnc.BlockNoToPlainOff(blockNo)
- lastBlockLen := newSize - plainOff
- var data []byte
- if lastBlockLen > 0 {
- var status fuse.Status
- data, status = f.doRead(plainOff, lastBlockLen)
- if status != fuse.OK {
- toggledlog.Warn.Printf("shrink doRead returned error: %v", err)
- return status
- }
- }
- // Truncate down to last complete block
- err = syscall.Ftruncate(int(f.fd.Fd()), int64(cipherOff))
- if err != nil {
- toggledlog.Warn.Printf("shrink Ftruncate returned error: %v", err)
- return fuse.ToStatus(err)
- }
- // Append partial block
- if lastBlockLen > 0 {
- _, status := f.doWrite(data, int64(plainOff))
- return status
- }
- return fuse.OK
- }
-}
-
-func (f *file) Chmod(mode uint32) fuse.Status {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- return fuse.ToStatus(f.fd.Chmod(os.FileMode(mode)))
-}
-
-func (f *file) Chown(uid uint32, gid uint32) fuse.Status {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- return fuse.ToStatus(f.fd.Chown(int(uid), int(gid)))
-}
-
-func (f *file) GetAttr(a *fuse.Attr) fuse.Status {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- toggledlog.Debug.Printf("file.GetAttr()")
- st := syscall.Stat_t{}
- err := syscall.Fstat(int(f.fd.Fd()), &st)
- if err != nil {
- return fuse.ToStatus(err)
- }
- a.FromStat(&st)
- a.Size = f.contentEnc.CipherSizeToPlainSize(a.Size)
-
- return fuse.OK
-}
-
-// Allocate - FUSE call, fallocate(2)
-var allocateWarned bool
-
-func (f *file) Allocate(off uint64, sz uint64, mode uint32) fuse.Status {
- // Only warn once
- if !allocateWarned {
- toggledlog.Warn.Printf("fallocate(2) is not supported, returning ENOSYS - see https://github.com/rfjakob/gocryptfs/issues/1")
- allocateWarned = true
- }
- return fuse.ENOSYS
-}
-
-const _UTIME_OMIT = ((1 << 30) - 2)
-
-func (f *file) Utimens(a *time.Time, m *time.Time) fuse.Status {
- f.fdLock.RLock()
- defer f.fdLock.RUnlock()
-
- ts := make([]syscall.Timespec, 2)
-
- if a == nil {
- ts[0].Nsec = _UTIME_OMIT
- } else {
- ts[0].Sec = a.Unix()
- }
-
- if m == nil {
- ts[1].Nsec = _UTIME_OMIT
- } else {
- ts[1].Sec = m.Unix()
- }
-
- fn := fmt.Sprintf("/proc/self/fd/%d", f.fd.Fd())
- return fuse.ToStatus(syscall.UtimesNano(fn, ts))
-}
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-26 09:56:15 +0000