docker-cli/components/engine/graphdriver/devmapper/devmapper.go

package devmapper

import (
	"errors"
	"fmt"
	"github.com/dotcloud/docker/utils"
	"runtime"
	"unsafe"
)

type DevmapperLogger interface {
	log(level int, file string, line int, dmError int, message string)
}

const (
	DeviceCreate TaskType = iota
	DeviceReload
	DeviceRemove
	DeviceRemoveAll
	DeviceSuspend
	DeviceResume
	DeviceInfo
	DeviceDeps
	DeviceRename
	DeviceVersion
	DeviceStatus
	DeviceTable
	DeviceWaitevent
	DeviceList
	DeviceClear
	DeviceMknodes
	DeviceListVersions
	DeviceTargetMsg
	DeviceSetGeometry
)

const (
	AddNodeOnResume AddNodeType = iota
	AddNodeOnCreate
)

var (
	ErrTaskRun                = errors.New("dm_task_run failed")
	ErrTaskSetName            = errors.New("dm_task_set_name failed")
	ErrTaskSetMessage         = errors.New("dm_task_set_message failed")
	ErrTaskSetAddNode         = errors.New("dm_task_set_add_node failed")
	ErrTaskSetRo              = errors.New("dm_task_set_ro failed")
	ErrTaskAddTarget          = errors.New("dm_task_add_target failed")
	ErrTaskSetSector          = errors.New("dm_task_set_sector failed")
	ErrTaskGetInfo            = errors.New("dm_task_get_info failed")
	ErrTaskSetCookie          = errors.New("dm_task_set_cookie failed")
	ErrNilCookie              = errors.New("cookie ptr can't be nil")
	ErrAttachLoopbackDevice   = errors.New("loopback mounting failed")
	ErrGetBlockSize           = errors.New("Can't get block size")
	ErrUdevWait               = errors.New("wait on udev cookie failed")
	ErrSetDevDir              = errors.New("dm_set_dev_dir failed")
	ErrGetLibraryVersion      = errors.New("dm_get_library_version failed")
	ErrCreateRemoveTask       = errors.New("Can't create task of type DeviceRemove")
	ErrRunRemoveDevice        = errors.New("running removeDevice failed")
	ErrInvalidAddNode         = errors.New("Invalide AddNoce type")
	ErrGetLoopbackBackingFile = errors.New("Unable to get loopback backing file")
	ErrLoopbackSetCapacity    = errors.New("Unable set loopback capacity")
)

type (
	Task struct {
		unmanaged *CDmTask
	}
	Info struct {
		Exists        int
		Suspended     int
		LiveTable     int
		InactiveTable int
		OpenCount     int32
		EventNr       uint32
		Major         uint32
		Minor         uint32
		ReadOnly      int
		TargetCount   int32
	}
	TaskType    int
	AddNodeType int
)

func (t *Task) destroy() {
	if t != nil {
		DmTaskDestroy(t.unmanaged)
		runtime.SetFinalizer(t, nil)
	}
}

func TaskCreate(tasktype TaskType) *Task {
	Ctask := DmTaskCreate(int(tasktype))
	if Ctask == nil {
		return nil
	}
	task := &Task{unmanaged: Ctask}
	runtime.SetFinalizer(task, (*Task).destroy)
	return task
}

func (t *Task) Run() error {
	if res := DmTaskRun(t.unmanaged); res != 1 {
		return ErrTaskRun
	}
	return nil
}

func (t *Task) SetName(name string) error {
	if res := DmTaskSetName(t.unmanaged, name); res != 1 {
		return ErrTaskSetName
	}
	return nil
}

func (t *Task) SetMessage(message string) error {
	if res := DmTaskSetMessage(t.unmanaged, message); res != 1 {
		return ErrTaskSetMessage
	}
	return nil
}

func (t *Task) SetSector(sector uint64) error {
	if res := DmTaskSetSector(t.unmanaged, sector); res != 1 {
		return ErrTaskSetSector
	}
	return nil
}

func (t *Task) SetCookie(cookie *uint, flags uint16) error {
	if cookie == nil {
		return ErrNilCookie
	}
	if res := DmTaskSetCookie(t.unmanaged, cookie, flags); res != 1 {
		return ErrTaskSetCookie
	}
	return nil
}

func (t *Task) SetAddNode(addNode AddNodeType) error {
	if addNode != AddNodeOnResume && addNode != AddNodeOnCreate {
		return ErrInvalidAddNode
	}
	if res := DmTaskSetAddNode(t.unmanaged, addNode); res != 1 {
		return ErrTaskSetAddNode
	}
	return nil
}

func (t *Task) SetRo() error {
	if res := DmTaskSetRo(t.unmanaged); res != 1 {
		return ErrTaskSetRo
	}
	return nil
}

func (t *Task) AddTarget(start, size uint64, ttype, params string) error {
	if res := DmTaskAddTarget(t.unmanaged, start, size,
		ttype, params); res != 1 {
		return ErrTaskAddTarget
	}
	return nil
}

func (t *Task) GetInfo() (*Info, error) {
	info := &Info{}
	if res := DmTaskGetInfo(t.unmanaged, info); res != 1 {
		return nil, ErrTaskGetInfo
	}
	return info, nil
}

func (t *Task) GetNextTarget(next uintptr) (nextPtr uintptr, start uint64,
	length uint64, targetType string, params string) {

	return DmGetNextTarget(t.unmanaged, next, &start, &length,
			&targetType, &params),
		start, length, targetType, params
}

func getLoopbackBackingFile(file *osFile) (uint64, uint64, error) {
	dev, inode, err := DmGetLoopbackBackingFile(file.Fd())
	if err != 0 {
		return 0, 0, ErrGetLoopbackBackingFile
	}
	return dev, inode, nil
}

func LoopbackSetCapacity(file *osFile) error {
	if err := DmLoopbackSetCapacity(file.Fd()); err != 0 {
		return ErrLoopbackSetCapacity
	}
	return nil
}

func FindLoopDeviceFor(file *osFile) *osFile {
	stat, err := file.Stat()
	if err != nil {
		return nil
	}
	targetInode := stat.Sys().(*sysStatT).Ino
	targetDevice := stat.Sys().(*sysStatT).Dev

	for i := 0; true; i++ {
		path := fmt.Sprintf("/dev/loop%d", i)

		file, err := osOpenFile(path, osORdWr, 0)
		if err != nil {
			if osIsNotExist(err) {
				return nil
			}

			// Ignore all errors until the first not-exist
			// we want to continue looking for the file
			continue
		}

		dev, inode, err := getLoopbackBackingFile(file)
		if err == nil && dev == targetDevice && inode == targetInode {
			return file
		}
		file.Close()
	}

	return nil
}

func UdevWait(cookie uint) error {
	if res := DmUdevWait(cookie); res != 1 {
		utils.Debugf("Failed to wait on udev cookie %d", cookie)
		return ErrUdevWait
	}
	return nil
}

func LogInitVerbose(level int) {
	DmLogInitVerbose(level)
}

var dmLogger DevmapperLogger = nil

func logInit(logger DevmapperLogger) {
	dmLogger = logger
	LogWithErrnoInit()
}

func SetDevDir(dir string) error {
	if res := DmSetDevDir(dir); res != 1 {
		utils.Debugf("Error dm_set_dev_dir")
		return ErrSetDevDir
	}
	return nil
}

func GetLibraryVersion() (string, error) {
	var version string
	if res := DmGetLibraryVersion(&version); res != 1 {
		return "", ErrGetLibraryVersion
	}
	return version, nil
}

// Useful helper for cleanup
func RemoveDevice(name string) error {
	task := TaskCreate(DeviceRemove)
	if task == nil {
		return ErrCreateRemoveTask
	}
	if err := task.SetName(name); err != nil {
		utils.Debugf("Can't set task name %s", name)
		return err
	}
	if err := task.Run(); err != nil {
		return ErrRunRemoveDevice
	}
	return nil
}

func GetBlockDeviceSize(file *osFile) (uint64, error) {
	size, errno := DmGetBlockSize(file.Fd())
	if size == -1 || errno != 0 {
		return 0, ErrGetBlockSize
	}
	return uint64(size), nil
}

// This is the programmatic example of "dmsetup create"
func createPool(poolName string, dataFile, metadataFile *osFile) error {
	task, err := createTask(DeviceCreate, poolName)
	if task == nil {
		return err
	}

	size, err := GetBlockDeviceSize(dataFile)
	if err != nil {
		return fmt.Errorf("Can't get data size")
	}

	params := metadataFile.Name() + " " + dataFile.Name() + " 128 32768"
	if err := task.AddTarget(0, size/512, "thin-pool", params); err != nil {
		return fmt.Errorf("Can't add target")
	}

	var cookie uint = 0
	if err := task.SetCookie(&cookie, 0); err != nil {
		return fmt.Errorf("Can't set cookie")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running DeviceCreate (createPool)")
	}

	UdevWait(cookie)

	return nil
}

func reloadPool(poolName string, dataFile, metadataFile *osFile) error {
	task, err := createTask(DeviceReload, poolName)
	if task == nil {
		return err
	}

	size, err := GetBlockDeviceSize(dataFile)
	if err != nil {
		return fmt.Errorf("Can't get data size")
	}

	params := metadataFile.Name() + " " + dataFile.Name() + " 128 32768"
	if err := task.AddTarget(0, size/512, "thin-pool", params); err != nil {
		return fmt.Errorf("Can't add target")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running DeviceCreate")
	}

	return nil
}

func createTask(t TaskType, name string) (*Task, error) {
	task := TaskCreate(t)
	if task == nil {
		return nil, fmt.Errorf("Can't create task of type %d", int(t))
	}
	if err := task.SetName(name); err != nil {
		return nil, fmt.Errorf("Can't set task name %s", name)
	}
	return task, nil
}

func getInfo(name string) (*Info, error) {
	task, err := createTask(DeviceInfo, name)
	if task == nil {
		return nil, err
	}
	if err := task.Run(); err != nil {
		return nil, err
	}
	return task.GetInfo()
}

func getStatus(name string) (uint64, uint64, string, string, error) {
	task, err := createTask(DeviceStatus, name)
	if task == nil {
		utils.Debugf("getStatus: Error createTask: %s", err)
		return 0, 0, "", "", err
	}
	if err := task.Run(); err != nil {
		utils.Debugf("getStatus: Error Run: %s", err)
		return 0, 0, "", "", err
	}

	devinfo, err := task.GetInfo()
	if err != nil {
		utils.Debugf("getStatus: Error GetInfo: %s", err)
		return 0, 0, "", "", err
	}
	if devinfo.Exists == 0 {
		utils.Debugf("getStatus: Non existing device %s", name)
		return 0, 0, "", "", fmt.Errorf("Non existing device %s", name)
	}

	_, start, length, targetType, params := task.GetNextTarget(0)
	return start, length, targetType, params, nil
}

func setTransactionId(poolName string, oldId uint64, newId uint64) error {
	task, err := createTask(DeviceTargetMsg, poolName)
	if task == nil {
		return err
	}

	if err := task.SetSector(0); err != nil {
		return fmt.Errorf("Can't set sector")
	}

	if err := task.SetMessage(fmt.Sprintf("set_transaction_id %d %d", oldId, newId)); err != nil {
		return fmt.Errorf("Can't set message")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running setTransactionId")
	}
	return nil
}

func suspendDevice(name string) error {
	task, err := createTask(DeviceSuspend, name)
	if task == nil {
		return err
	}
	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running DeviceSuspend: %s", err)
	}
	return nil
}

func resumeDevice(name string) error {
	task, err := createTask(DeviceResume, name)
	if task == nil {
		return err
	}

	var cookie uint = 0
	if err := task.SetCookie(&cookie, 0); err != nil {
		return fmt.Errorf("Can't set cookie")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running DeviceResume")
	}

	UdevWait(cookie)

	return nil
}

func createDevice(poolName string, deviceId int) error {
	utils.Debugf("[devmapper] createDevice(poolName=%v, deviceId=%v)", poolName, deviceId)
	task, err := createTask(DeviceTargetMsg, poolName)
	if task == nil {
		return err
	}

	if err := task.SetSector(0); err != nil {
		return fmt.Errorf("Can't set sector")
	}

	if err := task.SetMessage(fmt.Sprintf("create_thin %d", deviceId)); err != nil {
		return fmt.Errorf("Can't set message")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running createDevice")
	}
	return nil
}

func deleteDevice(poolName string, deviceId int) error {
	task, err := createTask(DeviceTargetMsg, poolName)
	if task == nil {
		return err
	}

	if err := task.SetSector(0); err != nil {
		return fmt.Errorf("Can't set sector")
	}

	if err := task.SetMessage(fmt.Sprintf("delete %d", deviceId)); err != nil {
		return fmt.Errorf("Can't set message")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running deleteDevice")
	}
	return nil
}

func removeDevice(name string) error {
	utils.Debugf("[devmapper] removeDevice START")
	defer utils.Debugf("[devmapper] removeDevice END")
	task, err := createTask(DeviceRemove, name)
	if task == nil {
		return err
	}
	if err = task.Run(); err != nil {
		return fmt.Errorf("Error running removeDevice")
	}
	return nil
}

func activateDevice(poolName string, name string, deviceId int, size uint64) error {
	task, err := createTask(DeviceCreate, name)
	if task == nil {
		return err
	}

	params := fmt.Sprintf("%s %d", poolName, deviceId)
	if err := task.AddTarget(0, size/512, "thin", params); err != nil {
		return fmt.Errorf("Can't add target")
	}
	if err := task.SetAddNode(AddNodeOnCreate); err != nil {
		return fmt.Errorf("Can't add node")
	}

	var cookie uint = 0
	if err := task.SetCookie(&cookie, 0); err != nil {
		return fmt.Errorf("Can't set cookie")
	}

	if err := task.Run(); err != nil {
		return fmt.Errorf("Error running DeviceCreate (activateDevice)")
	}

	UdevWait(cookie)

	return nil
}

func (devices *DeviceSet) createSnapDevice(poolName string, deviceId int, baseName string, baseDeviceId int) error {
	devinfo, _ := getInfo(baseName)
	doSuspend := devinfo != nil && devinfo.Exists != 0

	if doSuspend {
		if err := suspendDevice(baseName); err != nil {
			return err
		}
	}

	task, err := createTask(DeviceTargetMsg, poolName)
	if task == nil {
		if doSuspend {
			resumeDevice(baseName)
		}
		return err
	}

	if err := task.SetSector(0); err != nil {
		if doSuspend {
			resumeDevice(baseName)
		}
		return fmt.Errorf("Can't set sector")
	}

	if err := task.SetMessage(fmt.Sprintf("create_snap %d %d", deviceId, baseDeviceId)); err != nil {
		if doSuspend {
			resumeDevice(baseName)
		}
		return fmt.Errorf("Can't set message")
	}

	if err := task.Run(); err != nil {
		if doSuspend {
			resumeDevice(baseName)
		}
		return fmt.Errorf("Error running DeviceCreate (createSnapDevice)")
	}

	if doSuspend {
		if err := resumeDevice(baseName); err != nil {
			return err
		}
	}

	return nil
}

type LoopInfo64 struct {
	loDevice           uint64 /* ioctl r/o */
	loInode            uint64 /* ioctl r/o */
	loRdevice          uint64 /* ioctl r/o */
	loOffset           uint64
	loSizelimit        uint64 /* bytes, 0 == max available */
	loNumber           uint32 /* ioctl r/o */
	loEncrypt_type     uint32
	loEncrypt_key_size uint32 /* ioctl w/o */
	loFlags            uint32 /* ioctl r/o */
	loFileName         [LoNameSize]uint8
	loCryptName        [LoNameSize]uint8
	loEncryptKey       [LoKeySize]uint8 /* ioctl w/o */
	loInit             [2]uint64
}

// attachLoopDevice attaches the given sparse file to the next
// available loopback device. It returns an opened *osFile.
func attachLoopDevice(filename string) (loop *osFile, err error) {
	startIndex := 0

	// Try to retrieve the next available loopback device via syscall.
	// If it fails, we discard error and start loopking for a
	// loopback from index 0.
	if f, err := osOpenFile("/dev/loop-control", osORdOnly, 0644); err == nil {
		if index, _, err := sysSyscall(sysSysIoctl, f.Fd(), LoopCtlGetFree, 0); err != 0 {
			utils.Debugf("Error retrieving the next available loopback: %s", err)
		} else if index > 0 {
			startIndex = int(index)
		}
		f.Close()
	}

	// Open the given sparse file (use OpenFile because Open sets O_CLOEXEC)
	f, err := osOpenFile(filename, osORdWr, 0644)
	if err != nil {
		return nil, err
	}
	defer f.Close()

	var (
		target   string
		loopFile *osFile
	)
	// Start looking for a free /dev/loop
	for i := startIndex; ; {
		target = fmt.Sprintf("/dev/loop%d", i)

		fi, err := osStat(target)
		if err != nil {
			if osIsNotExist(err) {
				utils.Errorf("There are no more loopback device available.")
			}
		}

		// FIXME: Check here if target is a block device (in C: S_ISBLK(mode))
		if fi.IsDir() {
		}

		// Open the targeted loopback (use OpenFile because Open sets O_CLOEXEC)
		loopFile, err = osOpenFile(target, osORdWr, 0644)
		if err != nil {
			return nil, err
		}

		// Try to attach to the loop file
		if _, _, err := sysSyscall(sysSysIoctl, loopFile.Fd(), LoopSetFd, f.Fd()); err != 0 {
			loopFile.Close()
			// If the error is EBUSY, then try the next loopback
			if err != sysEBusy {
				utils.Errorf("Cannot set up loopback device %s: %s", target, err)
				return nil, err
			}
		} else {
			// In case of success, we finished. Break the loop.
			break
		}
		// In case of EBUSY error, the loop keep going.
	}

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

	// Set the status of the loopback device
	var loopInfo LoopInfo64

	// Due to type incompatibility (string vs [64]uint8), we copy data
	copy(loopInfo.loFileName[:], target[:])
	loopInfo.loOffset = 0
	loopInfo.loFlags = LoFlagsAutoClear

	if _, _, err := sysSyscall(sysSysIoctl, loopFile.Fd(), LoopSetStatus64, uintptr(unsafe.Pointer(&loopInfo))); err != 0 {
		// If the call failed, then free the loopback device
		utils.Errorf("Cannot set up loopback device info: %s", err)
		if _, _, err := sysSyscall(sysSysIoctl, loopFile.Fd(), LoopClrFd, 0); err != 0 {
			utils.Errorf("Error while cleaning up the loopback device")
		}
		loopFile.Close()
		return nil, err
	}

	return loopFile, nil
}