server.go

package sftp

// sftp server counterpart

import (
	"encoding"
	"errors"
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"
	"strconv"
	"sync"
	"syscall"
	"time"
)

const (
	// SftpServerWorkerCount defines the number of workers for the SFTP server
	SftpServerWorkerCount = 8
)

// Server is an SSH File Transfer Protocol (sftp) server.
// This is intended to provide the sftp subsystem to an ssh server daemon.
// This implementation currently supports most of sftp server protocol version 3,
// as specified at https://filezilla-project.org/specs/draft-ietf-secsh-filexfer-02.txt
type Server struct {
	*serverConn
	debugStream   io.Writer
	readOnly      bool
	pktMgr        *packetManager
	openFiles     map[string]*os.File
	openFilesLock sync.RWMutex
	handleCount   int
	workDir       string
	maxTxPacket   uint32
}

func (svr *Server) nextHandle(f *os.File) string {
	svr.openFilesLock.Lock()
	defer svr.openFilesLock.Unlock()
	svr.handleCount++
	handle := strconv.Itoa(svr.handleCount)
	svr.openFiles[handle] = f
	return handle
}

func (svr *Server) closeHandle(handle string) error {
	svr.openFilesLock.Lock()
	defer svr.openFilesLock.Unlock()
	if f, ok := svr.openFiles[handle]; ok {
		delete(svr.openFiles, handle)
		return f.Close()
	}

	return EBADF
}

func (svr *Server) getHandle(handle string) (*os.File, bool) {
	svr.openFilesLock.RLock()
	defer svr.openFilesLock.RUnlock()
	f, ok := svr.openFiles[handle]
	return f, ok
}

type serverRespondablePacket interface {
	encoding.BinaryUnmarshaler
	id() uint32
	respond(svr *Server) responsePacket