devicemapper: split out devicemapper bindings

This is a first pass at splitting out devicemapper into separate, usable
bindings.

Signed-off-by: Vincent Batts <vbatts@redhat.com>

devicemapper/devmapper.go

@@ -0,0 +1,673 @@
+// +build linux
+
+package devicemapper
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"runtime"
+	"syscall"
+
+	log "github.com/Sirupsen/logrus"
+)
+
+type DevmapperLogger interface {
+	DMLog(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")
+	ErrTaskGetDeps            = errors.New("dm_task_get_deps failed")
+	ErrTaskGetInfo            = errors.New("dm_task_get_info failed")
+	ErrTaskGetDriverVersion   = errors.New("dm_task_get_driver_version 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")
+	ErrBusy                   = errors.New("Device is Busy")
+
+	dmSawBusy  bool
+	dmSawExist bool
+)
+
+type (
+	Task struct {
+		unmanaged *CDmTask
+	}
+	Deps struct {
+		Count  uint32
+		Filler uint32
+		Device []uint64
+	}
+	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) GetDeps() (*Deps, error) {
+	var deps *Deps
+	if deps = DmTaskGetDeps(t.unmanaged); deps == nil {
+		return nil, ErrTaskGetDeps
+	}
+	return deps, 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) GetDriverVersion() (string, error) {
+	res := DmTaskGetDriverVersion(t.unmanaged)
+	if res == "" {
+		return "", ErrTaskGetDriverVersion
+	}
+	return res, 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 *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 LoopbackSetCapacity(file *os.File) error {
+	if err := ioctlLoopSetCapacity(file.Fd(), 0); err != nil {
+		log.Errorf("Error loopbackSetCapacity: %s", err)
+		return ErrLoopbackSetCapacity
+	}
+	return nil
+}
+
+func FindLoopDeviceFor(file *os.File) *os.File {
+	stat, err := file.Stat()
+	if err != nil {
+		return nil
+	}
+	targetInode := stat.Sys().(*syscall.Stat_t).Ino
+	targetDevice := stat.Sys().(*syscall.Stat_t).Dev
+
+	for i := 0; true; i++ {
+		path := fmt.Sprintf("/dev/loop%d", i)
+
+		file, err := os.OpenFile(path, os.O_RDWR, 0)
+		if err != nil {
+			if os.IsNotExist(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 {
+		log.Debugf("Failed to wait on udev cookie %d", cookie)
+		return ErrUdevWait
+	}
+	return nil
+}
+
+func LogInitVerbose(level int) {
+	DmLogInitVerbose(level)
+}
+
+var dmLogger DevmapperLogger = nil
+
+// initialize the logger for the device mapper library
+func LogInit(logger DevmapperLogger) {
+	dmLogger = logger
+	LogWithErrnoInit()
+}
+
+func SetDevDir(dir string) error {
+	if res := DmSetDevDir(dir); res != 1 {
+		log.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 {
+	// TODO(vbatts) just use the other removeDevice()
+	task := TaskCreate(DeviceRemove)
+	if task == nil {
+		return ErrCreateRemoveTask
+	}
+	if err := task.SetName(name); err != nil {
+		log.Debugf("Can't set task name %s", name)
+		return err
+	}
+	if err := task.Run(); err != nil {
+		return ErrRunRemoveDevice
+	}
+	return 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
+}
+
+func BlockDeviceDiscard(path string) error {
+	file, err := os.OpenFile(path, os.O_RDWR, 0)
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+
+	size, err := GetBlockDeviceSize(file)
+	if err != nil {
+		return err
+	}
+
+	if err := ioctlBlkDiscard(file.Fd(), 0, size); err != nil {
+		return err
+	}
+
+	// Without this sometimes the remove of the device that happens after
+	// discard fails with EBUSY.
+	syscall.Sync()
+
+	return nil
+}
+
+// This is the programmatic example of "dmsetup create"
+func CreatePool(poolName string, dataFile, metadataFile *os.File, poolBlockSize uint32) 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 %s", err)
+	}
+
+	params := fmt.Sprintf("%s %s %d 32768 1 skip_block_zeroing", metadataFile.Name(), dataFile.Name(), poolBlockSize)
+	if err := task.AddTarget(0, size/512, "thin-pool", params); err != nil {
+		return fmt.Errorf("Can't add target %s", err)
+	}
+
+	var cookie uint = 0
+	if err := task.SetCookie(&cookie, 0); err != nil {
+		return fmt.Errorf("Can't set cookie %s", err)
+	}
+
+	if err := task.Run(); err != nil {
+		return fmt.Errorf("Error running DeviceCreate (CreatePool) %s", err)
+	}
+
+	UdevWait(cookie)
+
+	return nil
+}
+
+func ReloadPool(poolName string, dataFile, metadataFile *os.File, poolBlockSize uint32) 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 %s", err)
+	}
+
+	params := fmt.Sprintf("%s %s %d 32768 1 skip_block_zeroing", metadataFile.Name(), dataFile.Name(), poolBlockSize)
+	if err := task.AddTarget(0, size/512, "thin-pool", params); err != nil {
+		return fmt.Errorf("Can't add target %s", err)
+	}
+
+	if err := task.Run(); err != nil {
+		return fmt.Errorf("Error running DeviceCreate %s", err)
+	}
+
+	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 GetDeps(name string) (*Deps, error) {
+	task, err := createTask(DeviceDeps, name)
+	if task == nil {
+		return nil, err
+	}
+	if err := task.Run(); err != nil {
+		return nil, err
+	}
+	return task.GetDeps()
+}
+
+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 GetDriverVersion() (string, error) {
+	task := TaskCreate(DeviceVersion)
+	if task == nil {
+		return "", fmt.Errorf("Can't create DeviceVersion task")
+	}
+	if err := task.Run(); err != nil {
+		return "", err
+	}
+	return task.GetDriverVersion()
+}
+
+func GetStatus(name string) (uint64, uint64, string, string, error) {
+	task, err := createTask(DeviceStatus, name)
+	if task == nil {
+		log.Debugf("GetStatus: Error createTask: %s", err)
+		return 0, 0, "", "", err
+	}
+	if err := task.Run(); err != nil {
+		log.Debugf("GetStatus: Error Run: %s", err)
+		return 0, 0, "", "", err
+	}
+
+	devinfo, err := task.GetInfo()
+	if err != nil {
+		log.Debugf("GetStatus: Error GetInfo: %s", err)
+		return 0, 0, "", "", err
+	}
+	if devinfo.Exists == 0 {
+		log.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 %s", err)
+	}
+
+	if err := task.SetMessage(fmt.Sprintf("set_transaction_id %d %d", oldId, newId)); err != nil {
+		return fmt.Errorf("Can't set message %s", err)
+	}
+
+	if err := task.Run(); err != nil {
+		return fmt.Errorf("Error running SetTransactionId %s", err)
+	}
+	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 %s", err)
+	}
+
+	if err := task.Run(); err != nil {
+		return fmt.Errorf("Error running DeviceResume %s", err)
+	}
+
+	UdevWait(cookie)
+
+	return nil
+}
+
+func CreateDevice(poolName string, deviceId *int) error {
+	log.Debugf("[devmapper] CreateDevice(poolName=%v, deviceId=%v)", poolName, *deviceId)
+
+	for {
+		task, err := createTask(DeviceTargetMsg, poolName)
+		if task == nil {
+			return err
+		}
+
+		if err := task.SetSector(0); err != nil {
+			return fmt.Errorf("Can't set sector %s", err)
+		}
+
+		if err := task.SetMessage(fmt.Sprintf("create_thin %d", *deviceId)); err != nil {
+			return fmt.Errorf("Can't set message %s", err)
+		}
+
+		dmSawExist = false
+		if err := task.Run(); err != nil {
+			if dmSawExist {
+				// Already exists, try next id
+				*deviceId++
+				continue
+			}
+			return fmt.Errorf("Error running CreateDevice %s", err)
+		}
+		break
+	}
+	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 %s", err)
+	}
+
+	if err := task.SetMessage(fmt.Sprintf("delete %d", deviceId)); err != nil {
+		return fmt.Errorf("Can't set message %s", err)
+	}
+
+	if err := task.Run(); err != nil {
+		return fmt.Errorf("Error running DeleteDevice %s", err)
+	}
+	return nil
+}
+
+func removeDevice(name string) error {
+	log.Debugf("[devmapper] RemoveDevice START")
+	defer log.Debugf("[devmapper] RemoveDevice END")
+	task, err := createTask(DeviceRemove, name)
+	if task == nil {
+		return err
+	}
+	dmSawBusy = false
+	if err = task.Run(); err != nil {
+		if dmSawBusy {
+			return ErrBusy
+		}
+		return fmt.Errorf("Error running RemoveDevice %s", err)
+	}
+	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 %s", err)
+	}
+	if err := task.SetAddNode(AddNodeOnCreate); err != nil {
+		return fmt.Errorf("Can't add node %s", err)
+	}
+
+	var cookie uint = 0
+	if err := task.SetCookie(&cookie, 0); err != nil {
+		return fmt.Errorf("Can't set cookie %s", err)
+	}
+
+	if err := task.Run(); err != nil {
+		return fmt.Errorf("Error running DeviceCreate (ActivateDevice) %s", err)
+	}
+
+	UdevWait(cookie)
+
+	return nil
+}
+
+func 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
+		}
+	}
+
+	for {
+		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 %s", err)
+		}
+
+		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 %s", err)
+		}
+
+		dmSawExist = false
+		if err := task.Run(); err != nil {
+			if dmSawExist {
+				// Already exists, try next id
+				*deviceId++
+				continue
+			}
+
+			if doSuspend {
+				ResumeDevice(baseName)
+			}
+			return fmt.Errorf("Error running DeviceCreate (createSnapDevice) %s", err)
+		}
+
+		break
+	}
+
+	if doSuspend {
+		if err := ResumeDevice(baseName); err != nil {
+			return err
+		}
+	}
+
+	return nil
+}