| package sftp |
| |
| import ( |
| "fmt" |
| "io" |
| "path/filepath" |
| "reflect" |
| "sync" |
| "syscall" |
| ) |
| |
| var maxTxPacket uint32 = 1 << 15 |
| |
| type handleHandler func(string) string |
| |
| type Handlers struct { |
| FileGet FileReader |
| FilePut FileWriter |
| FileCmd FileCmder |
| FileInfo FileInfoer |
| } |
| |
| // Server that abstracts the sftp protocol for a http request-like protocol |
| type RequestServer struct { |
| serverConn |
| Handlers Handlers |
| pktChan chan packet |
| openRequests map[string]*Request |
| openRequestLock sync.RWMutex |
| } |
| |
| // simple factory function |
| // one server per user-session |
| func NewRequestServer(rwc io.ReadWriteCloser) (*RequestServer, error) { |
| s := &RequestServer{ |
| serverConn: serverConn{ |
| conn: conn{ |
| Reader: rwc, |
| WriteCloser: rwc, |
| }, |
| }, |
| pktChan: make(chan packet, sftpServerWorkerCount), |
| openRequests: make(map[string]*Request), |
| } |
| |
| return s, nil |
| } |
| |
| func (rs *RequestServer) nextRequest(r *Request) string { |
| rs.openRequestLock.Lock() |
| defer rs.openRequestLock.Unlock() |
| rs.openRequests[r.Filepath] = r |
| return r.Filepath |
| } |
| |
| func (rs *RequestServer) getRequest(handle string) (*Request, bool) { |
| rs.openRequestLock.Lock() |
| defer rs.openRequestLock.Unlock() |
| r, ok := rs.openRequests[handle] |
| return r, ok |
| } |
| |
| func (rs *RequestServer) closeRequest(handle string) { |
| rs.openRequestLock.Lock() |
| defer rs.openRequestLock.Unlock() |
| if _, ok := rs.openRequests[handle]; ok { |
| delete(rs.openRequests, handle) |
| } |
| } |
| |
| // start serving requests from user session |
| func (rs *RequestServer) Serve() error { |
| var wg sync.WaitGroup |
| wg.Add(sftpServerWorkerCount) |
| for i := 0; i < sftpServerWorkerCount; i++ { |
| go func() { |
| defer wg.Done() |
| if err := rs.packetWorker(); err != nil { |
| rs.conn.Close() // shuts down recvPacket |
| } |
| }() |
| } |
| |
| var err error |
| var pktType uint8 |
| var pktBytes []byte |
| for { |
| pktType, pktBytes, err = rs.recvPacket() |
| if err != nil { break } |
| pkt, err := makePacket(rxPacket{fxp(pktType), pktBytes}) |
| if err != nil { break } |
| rs.pktChan <- pkt |
| } |
| |
| close(rs.pktChan) // shuts down sftpServerWorkers |
| wg.Wait() // wait for all workers to exit |
| return err |
| } |
| |
| func (rs *RequestServer) packetWorker() error { |
| for pkt := range rs.pktChan { |
| fmt.Println("Incoming Packet: ", pkt, reflect.TypeOf(pkt)) |
| var handle string |
| var rpkt resp_packet |
| var err error |
| switch pkt := pkt.(type) { |
| case *sshFxInitPacket: |
| rpkt = sshFxVersionPacket{sftpProtocolVersion, nil} |
| case *sshFxpClosePacket: |
| handle = pkt.getHandle() |
| rs.closeRequest(handle) |
| rpkt = statusFromError(pkt, nil) |
| case *sshFxpRealpathPacket: |
| rpkt = cleanPath(pkt) |
| case isOpener: |
| handle = rs.nextRequest(newRequest(pkt.getPath())) |
| rpkt = sshFxpHandlePacket{pkt.id(), handle} |
| case hasPath: |
| handle = rs.nextRequest(newRequest(pkt.getPath())) |
| rpkt = rs.request(handle, pkt) |
| case hasHandle: |
| handle = pkt.getHandle() |
| rpkt = rs.request(handle, pkt) |
| } |
| |
| fmt.Println("Reply Packet: ", rpkt, reflect.TypeOf(rpkt)) |
| err = rs.sendPacket(rpkt) |
| if err != nil { return err } |
| } |
| return nil |
| } |
| |
| func cleanPath(pkt *sshFxpRealpathPacket) resp_packet { |
| cleaned_path := filepath.Clean(pkt.getPath()) |
| return &sshFxpNamePacket{ |
| ID: pkt.id(), |
| NameAttrs: []sshFxpNameAttr{{ |
| Name: cleaned_path, |
| LongName: cleaned_path, |
| Attrs: emptyFileStat, |
| }}, |
| } |
| } |
| |
| func (rs *RequestServer) request(handle string, pkt packet) resp_packet { |
| var rpkt resp_packet |
| var err error |
| if request, ok := rs.getRequest(handle); ok { |
| // called here to keep packet handling out of request for testing |
| request.populate(pkt) |
| fmt.Println("Request Method: ", request.Method) |
| rpkt, err = request.handle(rs.Handlers) |
| if err != nil { rpkt = statusFromError(pkt, err) } |
| } else { rpkt = statusFromError(pkt, syscall.EBADF) } |
| return rpkt |
| } |