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Diffstat (limited to 'frontend/file.go')
-rw-r--r--frontend/file.go75
1 files changed, 69 insertions, 6 deletions
diff --git a/frontend/file.go b/frontend/file.go
index c5a02be..8014753 100644
--- a/frontend/file.go
+++ b/frontend/file.go
@@ -10,13 +10,40 @@ import (
"golang.org/x/net/context"
)
+func fixFlags(flags fuse.OpenFlags) (fuse.OpenFlags, bool) {
+ fmt.Printf("fixFlags: Before: %s\n", flags.String())
+ var writeOnly bool
+ // We always need read access to do read-modify-write cycles
+ if flags & fuse.OpenWriteOnly > 0 {
+ flags = flags &^ fuse.OpenWriteOnly
+ flags = flags | fuse.OpenReadWrite
+ writeOnly = true
+ }
+ // We also cannot open the file in append mode, we need to seek back for RMW
+ flags = flags &^ fuse.OpenAppend
+ fmt.Printf("fixFlags: After: %s\n", flags.String())
+ return flags, writeOnly
+}
+
+func max(x int, y int) int {
+ if x > y {
+ return x
+ }
+ return y
+}
+
type File struct {
*cluefs.File
crfs *cryptfs.CryptFS
+ // Remember if the file is supposed to be write-only
+ writeOnly bool
}
func (f *File) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenResponse) (fusefs.Handle, error) {
- fmt.Printf("File.Open: f.crfs=%p\n", f.crfs)
+ fmt.Printf("File.Open\n")
+
+ req.Flags, f.writeOnly = fixFlags(req.Flags)
+
h, err := f.File.Open(ctx, req, resp)
if err != nil {
return nil, err
@@ -29,32 +56,68 @@ func (f *File) Open(ctx context.Context, req *fuse.OpenRequest, resp *fuse.OpenR
}
func (f *File) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
- fmt.Printf("File.Read: f.crfs=%p\n", f.crfs)
iblocks := f.crfs.SplitRange(req.Offset, int64(req.Size))
for _, ib := range iblocks {
var partReq fuse.ReadRequest
var partResp fuse.ReadResponse
o, l := ib.CiphertextRange()
+ partReq.Offset = o
partReq.Size = int(l)
partResp.Data = make([]byte, int(l))
- partReq.Offset = o
err := f.File.Read(ctx, &partReq, &partResp)
if err != nil {
return err
}
plaintext, err := f.crfs.DecryptBlock(partResp.Data)
if err != nil {
- fmt.Printf("Read: Block %d: %s\n", ib.BlockNo, err.Error())
+ fmt.Printf("Read: Error reading block %d: %s\n", ib.BlockNo, err.Error())
return err
}
- plaintext = ib.CropBlock(partResp.Data)
+ plaintext = ib.CropBlock(plaintext)
resp.Data = append(resp.Data, plaintext...)
}
return nil
}
func (f *File) Write(ctx context.Context, req *fuse.WriteRequest, resp *fuse.WriteResponse) error {
+ fmt.Printf("File.Write\n")
+ resp.Size = 0
iblocks := f.crfs.SplitRange(req.Offset, int64(len(req.Data)))
- iblocks = iblocks
+ var blockData []byte
+ for _, ib := range iblocks {
+ if ib.IsPartial() {
+ // RMW
+ blockData = make([]byte, f.crfs.PlainBS())
+ var readReq fuse.ReadRequest
+ var readResp fuse.ReadResponse
+ o, l := ib.PlaintextRange()
+ readReq.Offset = o
+ readReq.Size = int(l)
+ err := f.Read(ctx, &readReq, &readResp)
+ if err != nil {
+ return err
+ }
+ copy(blockData, readResp.Data)
+ copy(blockData[ib.Offset:ib.Offset+ib.Length], req.Data)
+ blockLen := max(len(readResp.Data), int(ib.Offset+ib.Length))
+ blockData = blockData[0:blockLen]
+ } else {
+ blockData = req.Data[0:f.crfs.PlainBS()]
+ }
+ ciphertext := f.crfs.EncryptBlock(blockData)
+ var partReq fuse.WriteRequest
+ var partResp fuse.WriteResponse
+ o, _ := ib.CiphertextRange()
+ partReq.Data = ciphertext
+ partReq.Offset = o
+ err := f.File.Write(ctx, &partReq, &partResp)
+ if err != nil {
+ fmt.Printf("Write failure: %s\n", err.Error())
+ return err
+ }
+ // Remove written data from the front of the request
+ req.Data = req.Data[len(blockData):len(req.Data)]
+ resp.Size += len(blockData)
+ }
return nil
}