hardcoresushi/libgocryptfs
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reverse: rename readFile to clearer readBackingFile

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Also refactor the header generation for nicer code.
This commit is contained in:
Jakob Unterwurzacher 2016-09-20 16:26:23 +02:00
parent be9dfe3a89
commit 7faa267bd4
1 changed files with 16 additions and 13 deletions
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29
internal/fusefrontend_reverse/rfile.go
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@ -44,11 +44,11 @@ func (rf *reverseFile) GetAttr(*fuse.Attr) fuse.Status {
return fuse.ENOSYS
}
// readFile - read from the backing plaintext file, encrypt it, return the
// readBackingFile: read from the backing plaintext file, encrypt it, return the
// ciphertext.
// "off" ... ciphertext offset (must be >= HEADER_LEN)
// "length" ... ciphertext length
func (rf *reverseFile) readFile(off uint64, length uint64) (out []byte, err error) {
func (rf *reverseFile) readBackingFile(off uint64, length uint64) (out []byte, err error) {
blocks := rf.contentEnc.ExplodeCipherRange(off, length)
// Read the backing plaintext in one go
@ -84,24 +84,27 @@ func (rf *reverseFile) Read(buf []byte, ioff int64) (resultData fuse.ReadResult,
length := uint64(len(buf))
off := uint64(ioff)
var out bytes.Buffer
var headerPart []byte
var header []byte
// Create a virtual file header
// Synthesize file header
if off < contentenc.HEADER_LEN {
headerPart = zeroFileHeader.Pack()
headerPart = headerPart[off:]
if off+length < contentenc.HEADER_LEN {
headerPart = headerPart[:length]
header = zeroFileHeader.Pack()
// Truncate to requested part
end := int(off) + len(buf)
if end > len(header) {
end = len(header)
}
header = header[off:end]
// Write into output buffer and adjust offsets
out.Write(header)
hLen := uint64(len(header))
off += hLen
length -= hLen
}
out.Write(headerPart)
hLen := uint64(len(headerPart))
off += hLen
length -= hLen
// Read actual file data
if length > 0 {
fileData, err := rf.readFile(off, length)
fileData, err := rf.readBackingFile(off, length)
if err != nil {
return nil, fuse.ToStatus(err)
}