134 lines
3.5 KiB
Go
134 lines
3.5 KiB
Go
package frontend
|
|
|
|
import (
|
|
"fmt"
|
|
"github.com/rfjakob/gocryptfs/cryptfs"
|
|
"github.com/rfjakob/cluefs/lib/cluefs"
|
|
|
|
"bazil.org/fuse"
|
|
fusefs "bazil.org/fuse/fs"
|
|
"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\n")
|
|
|
|
req.Flags, f.writeOnly = fixFlags(req.Flags)
|
|
|
|
h, err := f.File.Open(ctx, req, resp)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
clueFile := h.(*cluefs.File)
|
|
return &File {
|
|
File: clueFile,
|
|
crfs: f.crfs,
|
|
}, nil
|
|
}
|
|
|
|
func (f *File) Read(ctx context.Context, req *fuse.ReadRequest, resp *fuse.ReadResponse) error {
|
|
iblocks := f.crfs.SplitRange(uint64(req.Offset), uint64(req.Size))
|
|
for _, ib := range iblocks {
|
|
var partReq fuse.ReadRequest
|
|
var partResp fuse.ReadResponse
|
|
o, l := ib.CiphertextRange()
|
|
partReq.Offset = int64(o)
|
|
partReq.Size = int(l)
|
|
partResp.Data = make([]byte, int(l))
|
|
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: Error reading block %d: %s\n", ib.BlockNo, err.Error())
|
|
return err
|
|
}
|
|
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(uint64(req.Offset), uint64(len(req.Data)))
|
|
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 = int64(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 = int64(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
|
|
}
|
|
|
|
func (f *File) Attr(ctx context.Context, attr *fuse.Attr) error {
|
|
fmt.Printf("Attr\n")
|
|
err := f.File.Node.Attr(ctx, attr)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
attr.Size = f.crfs.PlainSize(attr.Size)
|
|
return nil
|
|
}
|