aboutsummaryrefslogtreecommitdiff
path: root/internal/fusefrontend/file_holes.go
diff options
context:
space:
mode:
Diffstat (limited to 'internal/fusefrontend/file_holes.go')
-rw-r--r--internal/fusefrontend/file_holes.go32
1 files changed, 25 insertions, 7 deletions
diff --git a/internal/fusefrontend/file_holes.go b/internal/fusefrontend/file_holes.go
index ff626d1..5b7a244 100644
--- a/internal/fusefrontend/file_holes.go
+++ b/internal/fusefrontend/file_holes.go
@@ -8,17 +8,35 @@ import (
"github.com/rfjakob/gocryptfs/internal/tlog"
)
-// Will a write to plaintext offset "off" create a file hole in the ciphertext?
-func (f *file) createsCiphertextHole(plainSize uint64, off int64) bool {
+// Will a write to plaintext offset "targetOff" create a file hole in the
+// ciphertext? If yes, zero-pad the last ciphertext block.
+func (f *file) writePadHole(targetOff int64) fuse.Status {
+ // Get the current file size.
+ fi, err := f.fd.Stat()
+ if err != nil {
+ tlog.Warn.Printf("checkAndPadHole: Fstat failed: %v", err)
+ return fuse.ToStatus(err)
+ }
+ plainSize := f.contentEnc.CipherSizeToPlainSize(uint64(fi.Size()))
// Appending a single byte to the file (equivalent to writing to
// offset=plainSize) would write to "nextBlock".
nextBlock := f.contentEnc.PlainOffToBlockNo(plainSize)
// targetBlock is the block the user wants to write to.
- targetBlock := f.contentEnc.PlainOffToBlockNo(uint64(off))
- // If the write goes past the next block, nextBlock will have
- // to be zero-padded to the block boundary and at least nextBlock+1
- // becomes a file hole in the ciphertext.
- return targetBlock > nextBlock
+ targetBlock := f.contentEnc.PlainOffToBlockNo(uint64(targetOff))
+ // The write goes into an existing block or (if the last block was full)
+ // starts a new one directly after the last block. Nothing to do.
+ if targetBlock <= nextBlock {
+ return fuse.OK
+ }
+ // The write goes past the next block. nextBlock has
+ // to be zero-padded to the block boundary and (at least) nextBlock+1
+ // will become a file hole in the ciphertext.
+ status := f.zeroPad(plainSize)
+ if status != fuse.OK {
+ tlog.Warn.Printf("zeroPad returned error %v", status)
+ return status
+ }
+ return fuse.OK
}
// Zero-pad the file of size plainSize to the next block boundary