// useDirperm checks dirperm1 mount option can be used with the current
// version of aufs.
func useDirperm() bool {
	enableDirpermLock.Do(func() {
		base, err := ioutil.TempDir("", "docker-aufs-base")
		if err != nil {
			logrus.Errorf("error checking dirperm1: %v", err)
			return
		}
		defer os.RemoveAll(base)

		union, err := ioutil.TempDir("", "docker-aufs-union")
		if err != nil {
			logrus.Errorf("error checking dirperm1: %v", err)
			return
		}
		defer os.RemoveAll(union)

		opts := fmt.Sprintf("br:%s,dirperm1,xino=/dev/shm/aufs.xino", base)
		if err := mount("none", union, "aufs", 0, opts); err != nil {
			return
		}
		enableDirperm = true
		if err := Unmount(union); err != nil {
			logrus.Errorf("error checking dirperm1: failed to unmount %v", err)
		}
	})
	return enableDirperm
}

func openNextAvailableLoopback(index int, sparseFile *os.File) (loopFile *os.File, err error) {
	// Start looking for a free /dev/loop
	for {
		target := fmt.Sprintf("/dev/loop%d", index)
		index++

		fi, err := os.Stat(target)
		if err != nil {
			if os.IsNotExist(err) {
				log.Errorf("There are no more loopback devices available.")
			}
			return nil, ErrAttachLoopbackDevice
		}

		if fi.Mode()&os.ModeDevice != os.ModeDevice {
			log.Errorf("Loopback device %s is not a block device.", target)
			continue
		}

		// OpenFile adds O_CLOEXEC
		loopFile, err = os.OpenFile(target, os.O_RDWR, 0644)
		if err != nil {
			log.Errorf("Error opening loopback device: %s", err)
			return nil, ErrAttachLoopbackDevice
		}

		// Try to attach to the loop file
		if err := ioctlLoopSetFd(loopFile.Fd(), sparseFile.Fd()); err != nil {
			loopFile.Close()

			// If the error is EBUSY, then try the next loopback
			if err != syscall.EBUSY {
				log.Errorf("Cannot set up loopback device %s: %s", target, err)
				return nil, ErrAttachLoopbackDevice
			}

			// Otherwise, we keep going with the loop
			continue
		}
		// In case of success, we finished. Break the loop.
		break
	}

	// This can't happen, but let's be sure
	if loopFile == nil {
		log.Errorf("Unreachable code reached! Error attaching %s to a loopback device.", sparseFile.Name())
		return nil, ErrAttachLoopbackDevice
	}

	return loopFile, nil
}

// Write attempts to flush the events to the downstream sink until it succeeds
// or the sink is closed.
func (rs *retryingSink) Write(events ...Event) error {
	rs.mu.Lock()
	defer rs.mu.Unlock()

retry:

	if rs.closed {
		return ErrSinkClosed
	}

	if !rs.proceed() {
		logrus.Warnf("%v encountered too many errors, backing off", rs.sink)
		rs.wait(rs.failures.backoff)
		goto retry
	}

	if err := rs.write(events...); err != nil {
		if err == ErrSinkClosed {
			// terminal!
			return err
		}

		logrus.Errorf("retryingsink: error writing events: %v, retrying", err)
		goto retry
	}

	return nil
}

func (devices *DeviceSet) processPendingTransaction() error {
	if err := devices.loadTransactionMetaData(); err != nil {
		return err
	}

	// If there was open transaction but pool transaction Id is same
	// as open transaction Id, nothing to roll back.
	if devices.TransactionId == devices.OpenTransactionId {
		return nil
	}

	// If open transaction Id is less than pool transaction Id, something
	// is wrong. Bail out.
	if devices.OpenTransactionId < devices.TransactionId {
		log.Errorf("Open Transaction id %d is less than pool transaction id %d", devices.OpenTransactionId, devices.TransactionId)
		return nil
	}

	// Pool transaction Id is not same as open transaction. There is
	// a transaction which was not completed.
	if err := devices.rollbackTransaction(); err != nil {
		return fmt.Errorf("Rolling back open transaction failed: %s", err)
	}

	devices.OpenTransactionId = devices.TransactionId
	return nil
}

func (pm *PortMapper) Unmap(host net.Addr) error {
	pm.lock.Lock()
	defer pm.lock.Unlock()

	key := getKey(host)
	data, exists := pm.currentMappings[key]
	if !exists {
		return ErrPortNotMapped
	}

	data.userlandProxy.Stop()

	delete(pm.currentMappings, key)

	containerIP, containerPort := getIPAndPort(data.container)
	hostIP, hostPort := getIPAndPort(data.host)
	if err := pm.forward(iptables.Delete, data.proto, hostIP, hostPort, containerIP.String(), containerPort); err != nil {
		log.Errorf("Error on iptables delete: %s", err)
	}

	switch a := host.(type) {
	case *net.TCPAddr:
		return pm.allocator.ReleasePort(a.IP, "tcp", a.Port)
	case *net.UDPAddr:
		return pm.allocator.ReleasePort(a.IP, "udp", a.Port)
	}
	return nil
}

// getBuiltinDriver initalizes and returns the registered driver, but does not try to load from plugins
func getBuiltinDriver(name, home string, options []string, uidMaps, gidMaps []idtools.IDMap) (Driver, error) {
	if initFunc, exists := drivers[name]; exists {
		return initFunc(filepath.Join(home, name), options, uidMaps, gidMaps)
	}
	logrus.Errorf("Failed to built-in GetDriver graph %s %s", name, home)
	return nil, ErrNotSupported
}

func MatchesContentType(contentType, expectedType string) bool {
	mimetype, _, err := mime.ParseMediaType(contentType)
	if err != nil {
		log.Errorf("Error parsing media type: %s error: %s", contentType, err.Error())
	}
	return err == nil && mimetype == expectedType
}

// getStoredHashStates returns a slice of hashStateEntries for this upload.
func (bw *blobWriter) getStoredHashStates(ctx context.Context) ([]hashStateEntry, error) {
	uploadHashStatePathPrefix, err := bw.blobStore.pm.path(uploadHashStatePathSpec{
		name: bw.blobStore.repository.Name(),
		id:   bw.id,
		alg:  bw.digester.Digest().Algorithm(),
		list: true,
	})
	if err != nil {
		return nil, err
	}

	paths, err := bw.blobStore.driver.List(ctx, uploadHashStatePathPrefix)
	if err != nil {
		if _, ok := err.(storagedriver.PathNotFoundError); !ok {
			return nil, err
		}
		// Treat PathNotFoundError as no entries.
		paths = nil
	}

	hashStateEntries := make([]hashStateEntry, 0, len(paths))

	for _, p := range paths {
		pathSuffix := path.Base(p)
		// The suffix should be the offset.
		offset, err := strconv.ParseInt(pathSuffix, 0, 64)
		if err != nil {
			logrus.Errorf("unable to parse offset from upload state path %q: %s", p, err)
		}

		hashStateEntries = append(hashStateEntries, hashStateEntry{offset: offset, path: p})
	}

	return hashStateEntries, nil
}

func (d *Driver) Put(id string) error {
	err := d.DeviceSet.UnmountDevice(id)
	if err != nil {
		log.Errorf("Error unmounting device %s: %s", id, err)
	}
	return err
}

func httpError(w http.ResponseWriter, err error) {
	statusCode := http.StatusInternalServerError
	// FIXME: this is brittle and should not be necessary.
	// If we need to differentiate between different possible error types, we should
	// create appropriate error types with clearly defined meaning.
	errStr := strings.ToLower(err.Error())
	if strings.Contains(errStr, "no such") {
		statusCode = http.StatusNotFound
	} else if strings.Contains(errStr, "bad parameter") {
		statusCode = http.StatusBadRequest
	} else if strings.Contains(errStr, "conflict") {
		statusCode = http.StatusConflict
	} else if strings.Contains(errStr, "impossible") {
		statusCode = http.StatusNotAcceptable
	} else if strings.Contains(errStr, "wrong login/password") {
		statusCode = http.StatusUnauthorized
	} else if strings.Contains(errStr, "hasn't been activated") {
		statusCode = http.StatusForbidden
	}

	if err != nil {
		log.Errorf("HTTP Error: statusCode=%d %v", statusCode, err)
		http.Error(w, err.Error(), statusCode)
	}
}

func (cli *DockerCli) forwardAllSignals(cid string) chan os.Signal {
	sigc := make(chan os.Signal, 128)
	signal.CatchAll(sigc)
	go func() {
		for s := range sigc {
			if s == signal.SIGCHLD {
				continue
			}
			var sig string
			for sigStr, sigN := range signal.SignalMap {
				if sigN == s {
					sig = sigStr
					break
				}
			}
			if sig == "" {
				log.Errorf("Unsupported signal: %v. Discarding.", s)
			}
			if _, _, err := readBody(cli.call("POST", fmt.Sprintf("/containers/%s/kill?signal=%s", cid, sig), nil, false)); err != nil {
				log.Debugf("Error sending signal: %s", err)
			}
		}
	}()
	return sigc
}

func wsContainersAttach(eng *engine.Engine, version version.Version, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
	if err := parseForm(r); err != nil {
		return err
	}
	if vars == nil {
		return fmt.Errorf("Missing parameter")
	}

	if err := eng.Job("container_inspect", vars["name"]).Run(); err != nil {
		return err
	}

	h := websocket.Handler(func(ws *websocket.Conn) {
		defer ws.Close()
		job := eng.Job("attach", vars["name"])
		job.Setenv("logs", r.Form.Get("logs"))
		job.Setenv("stream", r.Form.Get("stream"))
		job.Setenv("stdin", r.Form.Get("stdin"))
		job.Setenv("stdout", r.Form.Get("stdout"))
		job.Setenv("stderr", r.Form.Get("stderr"))
		job.Stdin.Add(ws)
		job.Stdout.Add(ws)
		job.Stderr.Set(ws)
		if err := job.Run(); err != nil {
			log.Errorf("Error attaching websocket: %s", err)
		}
	})
	h.ServeHTTP(w, r)

	return nil
}

func makeHttpHandler(eng *engine.Engine, logging bool, localMethod string, localRoute string, handlerFunc HttpApiFunc, corsHeaders string, dockerVersion version.Version) http.HandlerFunc {
	return func(w http.ResponseWriter, r *http.Request) {
		// log the request
		log.Debugf("Calling %s %s", localMethod, localRoute)

		if logging {
			log.Infof("%s %s", r.Method, r.RequestURI)
		}

		if strings.Contains(r.Header.Get("User-Agent"), "Docker-Client/") {
			userAgent := strings.Split(r.Header.Get("User-Agent"), "/")
			if len(userAgent) == 2 && !dockerVersion.Equal(version.Version(userAgent[1])) {
				log.Debugf("Warning: client and server don't have the same version (client: %s, server: %s)", userAgent[1], dockerVersion)
			}
		}
		version := version.Version(mux.Vars(r)["version"])
		if version == "" {
			version = api.APIVERSION
		}
		if corsHeaders != "" {
			writeCorsHeaders(w, r, corsHeaders)
		}

		if version.GreaterThan(api.APIVERSION) {
			http.Error(w, fmt.Errorf("client and server don't have same version (client : %s, server: %s)", version, api.APIVERSION).Error(), http.StatusNotFound)
			return
		}

		if err := handlerFunc(eng, version, w, r, mux.Vars(r)); err != nil {
			log.Errorf("Handler for %s %s returned error: %s", localMethod, localRoute, err)
			httpError(w, err)
		}
	}
}

func LoopbackSetCapacity(file *os.File) error {
	if err := ioctlLoopSetCapacity(file.Fd(), 0); err != nil {
		log.Errorf("Error loopbackSetCapacity: %s", err)
		return ErrLoopbackSetCapacity
	}
	return nil
}

func GetTotalUsedFds() int {
	if fds, err := ioutil.ReadDir(fmt.Sprintf("/proc/%d/fd", os.Getpid())); err != nil {
		log.Errorf("Error opening /proc/%d/fd: %s", os.Getpid(), err)
	} else {
		return len(fds)
	}
	return -1
}

// Cleanup aufs and unmount all mountpoints
func (a *Driver) Cleanup() error {
	for id, m := range a.active {
		if err := a.unmount(m); err != nil {
			logrus.Errorf("Unmounting %s: %s", stringid.TruncateID(id), err)
		}
	}
	return mountpk.Unmount(a.root)
}

func getLoopbackBackingFile(file *os.File) (uint64, uint64, error) {
	loopInfo, err := ioctlLoopGetStatus64(file.Fd())
	if err != nil {
		log.Errorf("Error get loopback backing file: %s", err)
		return 0, 0, ErrGetLoopbackBackingFile
	}
	return loopInfo.loDevice, loopInfo.loInode, nil
}

func GetBlockDeviceSize(file *os.File) (uint64, error) {
	size, err := ioctlBlkGetSize64(file.Fd())
	if err != nil {
		log.Errorf("Error getblockdevicesize: %s", err)
		return 0, ErrGetBlockSize
	}
	return uint64(size), nil
}

// Matches returns true if relFilePath matches any of the patterns
func Matches(relFilePath string, patterns []string) (bool, error) {
	for _, exclude := range patterns {
		matched, err := filepath.Match(exclude, relFilePath)
		if err != nil {
			log.Errorf("Error matching: %s (pattern: %s)", relFilePath, exclude)
			return false, err
		}
		if matched {
			if filepath.Clean(relFilePath) == "." {
				log.Errorf("Can't exclude whole path, excluding pattern: %s", exclude)
				continue
			}
			log.Debugf("Skipping excluded path: %s", relFilePath)
			return true, nil
		}
	}
	return false, nil
}

func Unmount(target string) error {
	if err := exec.Command("auplink", target, "flush").Run(); err != nil {
		log.Errorf("Couldn't run auplink before unmount: %s", err)
	}
	if err := syscall.Unmount(target, 0); err != nil {
		return err
	}
	return nil
}