diff options
author | Jakob Unterwurzacher | 2016-02-06 19:27:59 +0100 |
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committer | Jakob Unterwurzacher | 2016-02-06 19:27:59 +0100 |
commit | 9078a77850dd680bfa938d9ed7c83600a60c0e7b (patch) | |
tree | 03ee83879c398307d450002e1f07e928cb743672 /pathfs_frontend/file.go | |
parent | 2b8cbd944149afe51fadddbd67ee4499d1d86250 (diff) |
Move pathfs_frontend to internal/fusefrontend
"git status" for reference:
renamed: pathfs_frontend/args.go -> internal/fusefrontend/args.go
renamed: pathfs_frontend/compat_darwin.go -> internal/fusefrontend/compat_darwin.go
renamed: pathfs_frontend/compat_linux.go -> internal/fusefrontend/compat_linux.go
renamed: pathfs_frontend/file.go -> internal/fusefrontend/file.go
renamed: pathfs_frontend/file_holes.go -> internal/fusefrontend/file_holes.go
renamed: pathfs_frontend/fs.go -> internal/fusefrontend/fs.go
renamed: pathfs_frontend/fs_dir.go -> internal/fusefrontend/fs_dir.go
renamed: pathfs_frontend/names.go -> internal/fusefrontend/names.go
renamed: pathfs_frontend/write_lock.go -> internal/fusefrontend/write_lock.go
modified: main.go
Diffstat (limited to 'pathfs_frontend/file.go')
-rw-r--r-- | pathfs_frontend/file.go | 501 |
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)) -} |