//go:build windows // +build windows package fs import ( "fmt" "path/filepath" "runtime" "strings" "syscall" "unsafe" ole "github.com/go-ole/go-ole" "github.com/restic/restic/internal/errors" "golang.org/x/sys/windows" ) // HRESULT is a custom type for the windows api HRESULT type. type HRESULT uint // HRESULT constant values necessary for using VSS api. const ( S_OK HRESULT = 0x00000000 E_ACCESSDENIED HRESULT = 0x80070005 E_OUTOFMEMORY HRESULT = 0x8007000E E_INVALIDARG HRESULT = 0x80070057 VSS_E_BAD_STATE HRESULT = 0x80042301 VSS_E_UNEXPECTED HRESULT = 0x80042302 VSS_E_PROVIDER_ALREADY_REGISTERED HRESULT = 0x80042303 VSS_E_PROVIDER_NOT_REGISTERED HRESULT = 0x80042304 VSS_E_PROVIDER_VETO HRESULT = 0x80042306 VSS_E_PROVIDER_IN_USE HRESULT = 0x80042307 VSS_E_OBJECT_NOT_FOUND HRESULT = 0x80042308 VSS_E_VOLUME_NOT_SUPPORTED HRESULT = 0x8004230C VSS_E_VOLUME_NOT_SUPPORTED_BY_PROVIDER HRESULT = 0x8004230E VSS_E_OBJECT_ALREADY_EXISTS HRESULT = 0x8004230D VSS_E_UNEXPECTED_PROVIDER_ERROR HRESULT = 0x8004230F VSS_E_CORRUPT_XML_DOCUMENT HRESULT = 0x80042310 VSS_E_INVALID_XML_DOCUMENT HRESULT = 0x80042311 VSS_E_MAXIMUM_NUMBER_OF_VOLUMES_REACHED HRESULT = 0x80042312 VSS_E_FLUSH_WRITES_TIMEOUT HRESULT = 0x80042313 VSS_E_HOLD_WRITES_TIMEOUT HRESULT = 0x80042314 VSS_E_UNEXPECTED_WRITER_ERROR HRESULT = 0x80042315 VSS_E_SNAPSHOT_SET_IN_PROGRESS HRESULT = 0x80042316 VSS_E_MAXIMUM_NUMBER_OF_SNAPSHOTS_REACHED HRESULT = 0x80042317 VSS_E_WRITER_INFRASTRUCTURE HRESULT = 0x80042318 VSS_E_WRITER_NOT_RESPONDING HRESULT = 0x80042319 VSS_E_WRITER_ALREADY_SUBSCRIBED HRESULT = 0x8004231A VSS_E_UNSUPPORTED_CONTEXT HRESULT = 0x8004231B VSS_E_VOLUME_IN_USE HRESULT = 0x8004231D VSS_E_MAXIMUM_DIFFAREA_ASSOCIATIONS_REACHED HRESULT = 0x8004231E VSS_E_INSUFFICIENT_STORAGE HRESULT = 0x8004231F VSS_E_NO_SNAPSHOTS_IMPORTED HRESULT = 0x80042320 VSS_E_SOME_SNAPSHOTS_NOT_IMPORTED HRESULT = 0x80042321 VSS_E_MAXIMUM_NUMBER_OF_REMOTE_MACHINES_REACHED HRESULT = 0x80042322 VSS_E_REMOTE_SERVER_UNAVAILABLE HRESULT = 0x80042323 VSS_E_REMOTE_SERVER_UNSUPPORTED HRESULT = 0x80042324 VSS_E_REVERT_IN_PROGRESS HRESULT = 0x80042325 VSS_E_REVERT_VOLUME_LOST HRESULT = 0x80042326 VSS_E_REBOOT_REQUIRED HRESULT = 0x80042327 VSS_E_TRANSACTION_FREEZE_TIMEOUT HRESULT = 0x80042328 VSS_E_TRANSACTION_THAW_TIMEOUT HRESULT = 0x80042329 VSS_E_VOLUME_NOT_LOCAL HRESULT = 0x8004232D VSS_E_CLUSTER_TIMEOUT HRESULT = 0x8004232E VSS_E_WRITERERROR_INCONSISTENTSNAPSHOT HRESULT = 0x800423F0 VSS_E_WRITERERROR_OUTOFRESOURCES HRESULT = 0x800423F1 VSS_E_WRITERERROR_TIMEOUT HRESULT = 0x800423F2 VSS_E_WRITERERROR_RETRYABLE HRESULT = 0x800423F3 VSS_E_WRITERERROR_NONRETRYABLE HRESULT = 0x800423F4 VSS_E_WRITERERROR_RECOVERY_FAILED HRESULT = 0x800423F5 VSS_E_BREAK_REVERT_ID_FAILED HRESULT = 0x800423F6 VSS_E_LEGACY_PROVIDER HRESULT = 0x800423F7 VSS_E_MISSING_DISK HRESULT = 0x800423F8 VSS_E_MISSING_HIDDEN_VOLUME HRESULT = 0x800423F9 VSS_E_MISSING_VOLUME HRESULT = 0x800423FA VSS_E_AUTORECOVERY_FAILED HRESULT = 0x800423FB VSS_E_DYNAMIC_DISK_ERROR HRESULT = 0x800423FC VSS_E_NONTRANSPORTABLE_BCD HRESULT = 0x800423FD VSS_E_CANNOT_REVERT_DISKID HRESULT = 0x800423FE VSS_E_RESYNC_IN_PROGRESS HRESULT = 0x800423FF VSS_E_CLUSTER_ERROR HRESULT = 0x80042400 VSS_E_UNSELECTED_VOLUME HRESULT = 0x8004232A VSS_E_SNAPSHOT_NOT_IN_SET HRESULT = 0x8004232B VSS_E_NESTED_VOLUME_LIMIT HRESULT = 0x8004232C VSS_E_NOT_SUPPORTED HRESULT = 0x8004232F VSS_E_WRITERERROR_PARTIAL_FAILURE HRESULT = 0x80042336 VSS_E_WRITER_STATUS_NOT_AVAILABLE HRESULT = 0x80042409 ) // hresultToString maps a HRESULT value to a human readable string. var hresultToString = map[HRESULT]string{ S_OK: "S_OK", E_ACCESSDENIED: "E_ACCESSDENIED", E_OUTOFMEMORY: "E_OUTOFMEMORY", E_INVALIDARG: "E_INVALIDARG", VSS_E_BAD_STATE: "VSS_E_BAD_STATE", VSS_E_UNEXPECTED: "VSS_E_UNEXPECTED", VSS_E_PROVIDER_ALREADY_REGISTERED: "VSS_E_PROVIDER_ALREADY_REGISTERED", VSS_E_PROVIDER_NOT_REGISTERED: "VSS_E_PROVIDER_NOT_REGISTERED", VSS_E_PROVIDER_VETO: "VSS_E_PROVIDER_VETO", VSS_E_PROVIDER_IN_USE: "VSS_E_PROVIDER_IN_USE", VSS_E_OBJECT_NOT_FOUND: "VSS_E_OBJECT_NOT_FOUND", VSS_E_VOLUME_NOT_SUPPORTED: "VSS_E_VOLUME_NOT_SUPPORTED", VSS_E_VOLUME_NOT_SUPPORTED_BY_PROVIDER: "VSS_E_VOLUME_NOT_SUPPORTED_BY_PROVIDER", VSS_E_OBJECT_ALREADY_EXISTS: "VSS_E_OBJECT_ALREADY_EXISTS", VSS_E_UNEXPECTED_PROVIDER_ERROR: "VSS_E_UNEXPECTED_PROVIDER_ERROR", VSS_E_CORRUPT_XML_DOCUMENT: "VSS_E_CORRUPT_XML_DOCUMENT", VSS_E_INVALID_XML_DOCUMENT: "VSS_E_INVALID_XML_DOCUMENT", VSS_E_MAXIMUM_NUMBER_OF_VOLUMES_REACHED: "VSS_E_MAXIMUM_NUMBER_OF_VOLUMES_REACHED", VSS_E_FLUSH_WRITES_TIMEOUT: "VSS_E_FLUSH_WRITES_TIMEOUT", VSS_E_HOLD_WRITES_TIMEOUT: "VSS_E_HOLD_WRITES_TIMEOUT", VSS_E_UNEXPECTED_WRITER_ERROR: "VSS_E_UNEXPECTED_WRITER_ERROR", VSS_E_SNAPSHOT_SET_IN_PROGRESS: "VSS_E_SNAPSHOT_SET_IN_PROGRESS", VSS_E_MAXIMUM_NUMBER_OF_SNAPSHOTS_REACHED: "VSS_E_MAXIMUM_NUMBER_OF_SNAPSHOTS_REACHED", VSS_E_WRITER_INFRASTRUCTURE: "VSS_E_WRITER_INFRASTRUCTURE", VSS_E_WRITER_NOT_RESPONDING: "VSS_E_WRITER_NOT_RESPONDING", VSS_E_WRITER_ALREADY_SUBSCRIBED: "VSS_E_WRITER_ALREADY_SUBSCRIBED", VSS_E_UNSUPPORTED_CONTEXT: "VSS_E_UNSUPPORTED_CONTEXT", VSS_E_VOLUME_IN_USE: "VSS_E_VOLUME_IN_USE", VSS_E_MAXIMUM_DIFFAREA_ASSOCIATIONS_REACHED: "VSS_E_MAXIMUM_DIFFAREA_ASSOCIATIONS_REACHED", VSS_E_INSUFFICIENT_STORAGE: "VSS_E_INSUFFICIENT_STORAGE", VSS_E_NO_SNAPSHOTS_IMPORTED: "VSS_E_NO_SNAPSHOTS_IMPORTED", VSS_E_SOME_SNAPSHOTS_NOT_IMPORTED: "VSS_E_SOME_SNAPSHOTS_NOT_IMPORTED", VSS_E_MAXIMUM_NUMBER_OF_REMOTE_MACHINES_REACHED: "VSS_E_MAXIMUM_NUMBER_OF_REMOTE_MACHINES_REACHED", VSS_E_REMOTE_SERVER_UNAVAILABLE: "VSS_E_REMOTE_SERVER_UNAVAILABLE", VSS_E_REMOTE_SERVER_UNSUPPORTED: "VSS_E_REMOTE_SERVER_UNSUPPORTED", VSS_E_REVERT_IN_PROGRESS: "VSS_E_REVERT_IN_PROGRESS", VSS_E_REVERT_VOLUME_LOST: "VSS_E_REVERT_VOLUME_LOST", VSS_E_REBOOT_REQUIRED: "VSS_E_REBOOT_REQUIRED", VSS_E_TRANSACTION_FREEZE_TIMEOUT: "VSS_E_TRANSACTION_FREEZE_TIMEOUT", VSS_E_TRANSACTION_THAW_TIMEOUT: "VSS_E_TRANSACTION_THAW_TIMEOUT", VSS_E_VOLUME_NOT_LOCAL: "VSS_E_VOLUME_NOT_LOCAL", VSS_E_CLUSTER_TIMEOUT: "VSS_E_CLUSTER_TIMEOUT", VSS_E_WRITERERROR_INCONSISTENTSNAPSHOT: "VSS_E_WRITERERROR_INCONSISTENTSNAPSHOT", VSS_E_WRITERERROR_OUTOFRESOURCES: "VSS_E_WRITERERROR_OUTOFRESOURCES", VSS_E_WRITERERROR_TIMEOUT: "VSS_E_WRITERERROR_TIMEOUT", VSS_E_WRITERERROR_RETRYABLE: "VSS_E_WRITERERROR_RETRYABLE", VSS_E_WRITERERROR_NONRETRYABLE: "VSS_E_WRITERERROR_NONRETRYABLE", VSS_E_WRITERERROR_RECOVERY_FAILED: "VSS_E_WRITERERROR_RECOVERY_FAILED", VSS_E_BREAK_REVERT_ID_FAILED: "VSS_E_BREAK_REVERT_ID_FAILED", VSS_E_LEGACY_PROVIDER: "VSS_E_LEGACY_PROVIDER", VSS_E_MISSING_DISK: "VSS_E_MISSING_DISK", VSS_E_MISSING_HIDDEN_VOLUME: "VSS_E_MISSING_HIDDEN_VOLUME", VSS_E_MISSING_VOLUME: "VSS_E_MISSING_VOLUME", VSS_E_AUTORECOVERY_FAILED: "VSS_E_AUTORECOVERY_FAILED", VSS_E_DYNAMIC_DISK_ERROR: "VSS_E_DYNAMIC_DISK_ERROR", VSS_E_NONTRANSPORTABLE_BCD: "VSS_E_NONTRANSPORTABLE_BCD", VSS_E_CANNOT_REVERT_DISKID: "VSS_E_CANNOT_REVERT_DISKID", VSS_E_RESYNC_IN_PROGRESS: "VSS_E_RESYNC_IN_PROGRESS", VSS_E_CLUSTER_ERROR: "VSS_E_CLUSTER_ERROR", VSS_E_UNSELECTED_VOLUME: "VSS_E_UNSELECTED_VOLUME", VSS_E_SNAPSHOT_NOT_IN_SET: "VSS_E_SNAPSHOT_NOT_IN_SET", VSS_E_NESTED_VOLUME_LIMIT: "VSS_E_NESTED_VOLUME_LIMIT", VSS_E_NOT_SUPPORTED: "VSS_E_NOT_SUPPORTED", VSS_E_WRITERERROR_PARTIAL_FAILURE: "VSS_E_WRITERERROR_PARTIAL_FAILURE", VSS_E_WRITER_STATUS_NOT_AVAILABLE: "VSS_E_WRITER_STATUS_NOT_AVAILABLE", } // Str converts a HRESULT to a human readable string. func (h HRESULT) Str() string { if i, ok := hresultToString[h]; ok { return i } return "UNKNOWN" } // VssError encapsulates errors returned from calling VSS api. type vssError struct { text string hresult HRESULT } // NewVssError creates a new VSS api error. func newVssError(text string, hresult HRESULT) error { return &vssError{text: text, hresult: hresult} } // NewVssError creates a new VSS api error. func newVssErrorIfResultNotOK(text string, hresult HRESULT) error { if hresult != S_OK { return newVssError(text, hresult) } return nil } // Error implements the error interface. func (e *vssError) Error() string { return fmt.Sprintf("VSS error: %s: %s (%#x)", e.text, e.hresult.Str(), e.hresult) } // VssError encapsulates errors returned from calling VSS api. type vssTextError struct { text string } // NewVssTextError creates a new VSS api error. func newVssTextError(text string) error { return &vssTextError{text: text} } // Error implements the error interface. func (e *vssTextError) Error() string { return fmt.Sprintf("VSS error: %s", e.text) } // VssContext is a custom type for the windows api VssContext type. type VssContext uint // VssContext constant values necessary for using VSS api. const ( VSS_CTX_BACKUP VssContext = iota VSS_CTX_FILE_SHARE_BACKUP VSS_CTX_NAS_ROLLBACK VSS_CTX_APP_ROLLBACK VSS_CTX_CLIENT_ACCESSIBLE VSS_CTX_CLIENT_ACCESSIBLE_WRITERS VSS_CTX_ALL ) // VssBackup is a custom type for the windows api VssBackup type. type VssBackup uint // VssBackup constant values necessary for using VSS api. const ( VSS_BT_UNDEFINED VssBackup = iota VSS_BT_FULL VSS_BT_INCREMENTAL VSS_BT_DIFFERENTIAL VSS_BT_LOG VSS_BT_COPY VSS_BT_OTHER ) // VssObjectType is a custom type for the windows api VssObjectType type. type VssObjectType uint // VssObjectType constant values necessary for using VSS api. const ( VSS_OBJECT_UNKNOWN VssObjectType = iota VSS_OBJECT_NONE VSS_OBJECT_SNAPSHOT_SET VSS_OBJECT_SNAPSHOT VSS_OBJECT_PROVIDER VSS_OBJECT_TYPE_COUNT ) // UUID_IVSS defines the GUID of IVssBackupComponents. var UUID_IVSS = ole.NewGUID("{665c1d5f-c218-414d-a05d-7fef5f9d5c86}") // IVssBackupComponents VSS api interface. type IVssBackupComponents struct { ole.IUnknown } // IVssBackupComponentsVTable is the vtable for IVssBackupComponents. type IVssBackupComponentsVTable struct { ole.IUnknownVtbl getWriterComponentsCount uintptr getWriterComponents uintptr initializeForBackup uintptr setBackupState uintptr initializeForRestore uintptr setRestoreState uintptr gatherWriterMetadata uintptr getWriterMetadataCount uintptr getWriterMetadata uintptr freeWriterMetadata uintptr addComponent uintptr prepareForBackup uintptr abortBackup uintptr gatherWriterStatus uintptr getWriterStatusCount uintptr freeWriterStatus uintptr getWriterStatus uintptr setBackupSucceeded uintptr setBackupOptions uintptr setSelectedForRestore uintptr setRestoreOptions uintptr setAdditionalRestores uintptr setPreviousBackupStamp uintptr saveAsXML uintptr backupComplete uintptr addAlternativeLocationMapping uintptr addRestoreSubcomponent uintptr setFileRestoreStatus uintptr addNewTarget uintptr setRangesFilePath uintptr preRestore uintptr postRestore uintptr setContext uintptr startSnapshotSet uintptr addToSnapshotSet uintptr doSnapshotSet uintptr deleteSnapshots uintptr importSnapshots uintptr breakSnapshotSet uintptr getSnapshotProperties uintptr query uintptr isVolumeSupported uintptr disableWriterClasses uintptr enableWriterClasses uintptr disableWriterInstances uintptr exposeSnapshot uintptr revertToSnapshot uintptr queryRevertStatus uintptr } // getVTable returns the vtable for IVssBackupComponents. func (vss *IVssBackupComponents) getVTable() *IVssBackupComponentsVTable { return (*IVssBackupComponentsVTable)(unsafe.Pointer(vss.RawVTable)) } // AbortBackup calls the equivalent VSS api. func (vss *IVssBackupComponents) AbortBackup() error { result, _, _ := syscall.Syscall(vss.getVTable().abortBackup, 1, uintptr(unsafe.Pointer(vss)), 0, 0) return newVssErrorIfResultNotOK("AbortBackup() failed", HRESULT(result)) } // InitializeForBackup calls the equivalent VSS api. func (vss *IVssBackupComponents) InitializeForBackup() error { result, _, _ := syscall.Syscall(vss.getVTable().initializeForBackup, 2, uintptr(unsafe.Pointer(vss)), 0, 0) return newVssErrorIfResultNotOK("InitializeForBackup() failed", HRESULT(result)) } // SetContext calls the equivalent VSS api. func (vss *IVssBackupComponents) SetContext(context VssContext) error { result, _, _ := syscall.Syscall(vss.getVTable().setContext, 2, uintptr(unsafe.Pointer(vss)), uintptr(context), 0) return newVssErrorIfResultNotOK("SetContext() failed", HRESULT(result)) } // GatherWriterMetadata calls the equivalent VSS api. func (vss *IVssBackupComponents) GatherWriterMetadata() (*IVSSAsync, error) { var oleIUnknown *ole.IUnknown result, _, _ := syscall.Syscall(vss.getVTable().gatherWriterMetadata, 2, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&oleIUnknown)), 0) err := newVssErrorIfResultNotOK("GatherWriterMetadata() failed", HRESULT(result)) return vss.convertToVSSAsync(oleIUnknown, err) } // convertToVSSAsync looks up IVSSAsync interface if given result // is a success. func (vss *IVssBackupComponents) convertToVSSAsync( oleIUnknown *ole.IUnknown, err error) (*IVSSAsync, error) { if err != nil { return nil, err } comInterface, err := queryInterface(oleIUnknown, UIID_IVSS_ASYNC) if err != nil { return nil, err } iVssAsync := (*IVSSAsync)(unsafe.Pointer(comInterface)) return iVssAsync, nil } // IsVolumeSupported calls the equivalent VSS api. func (vss *IVssBackupComponents) IsVolumeSupported(volumeName string) (bool, error) { volumeNamePointer, err := syscall.UTF16PtrFromString(volumeName) if err != nil { panic(err) } var isSupportedRaw uint32 var result uintptr if runtime.GOARCH == "386" { id := (*[4]uintptr)(unsafe.Pointer(ole.IID_NULL)) result, _, _ = syscall.Syscall9(vss.getVTable().isVolumeSupported, 7, uintptr(unsafe.Pointer(vss)), id[0], id[1], id[2], id[3], uintptr(unsafe.Pointer(volumeNamePointer)), uintptr(unsafe.Pointer(&isSupportedRaw)), 0, 0) } else { result, _, _ = syscall.Syscall6(vss.getVTable().isVolumeSupported, 4, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(ole.IID_NULL)), uintptr(unsafe.Pointer(volumeNamePointer)), uintptr(unsafe.Pointer(&isSupportedRaw)), 0, 0) } var isSupported bool if isSupportedRaw == 0 { isSupported = false } else { isSupported = true } return isSupported, newVssErrorIfResultNotOK("IsVolumeSupported() failed", HRESULT(result)) } // StartSnapshotSet calls the equivalent VSS api. func (vss *IVssBackupComponents) StartSnapshotSet() (ole.GUID, error) { var snapshotSetID ole.GUID result, _, _ := syscall.Syscall(vss.getVTable().startSnapshotSet, 2, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&snapshotSetID)), 0, ) return snapshotSetID, newVssErrorIfResultNotOK("StartSnapshotSet() failed", HRESULT(result)) } // AddToSnapshotSet calls the equivalent VSS api. func (vss *IVssBackupComponents) AddToSnapshotSet(volumeName string, idSnapshot *ole.GUID) error { volumeNamePointer, err := syscall.UTF16PtrFromString(volumeName) if err != nil { panic(err) } var result uintptr = 0 if runtime.GOARCH == "386" { id := (*[4]uintptr)(unsafe.Pointer(ole.IID_NULL)) result, _, _ = syscall.Syscall9(vss.getVTable().addToSnapshotSet, 7, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(volumeNamePointer)), id[0], id[1], id[2], id[3], uintptr(unsafe.Pointer(idSnapshot)), 0, 0) } else { result, _, _ = syscall.Syscall6(vss.getVTable().addToSnapshotSet, 4, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(volumeNamePointer)), uintptr(unsafe.Pointer(ole.IID_NULL)), uintptr(unsafe.Pointer(idSnapshot)), 0, 0) } return newVssErrorIfResultNotOK("AddToSnapshotSet() failed", HRESULT(result)) } // PrepareForBackup calls the equivalent VSS api. func (vss *IVssBackupComponents) PrepareForBackup() (*IVSSAsync, error) { var oleIUnknown *ole.IUnknown result, _, _ := syscall.Syscall(vss.getVTable().prepareForBackup, 2, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&oleIUnknown)), 0) err := newVssErrorIfResultNotOK("PrepareForBackup() failed", HRESULT(result)) return vss.convertToVSSAsync(oleIUnknown, err) } // apiBoolToInt converts a bool for use calling the VSS api func apiBoolToInt(input bool) uint { if input { return 1 } return 0 } // SetBackupState calls the equivalent VSS api. func (vss *IVssBackupComponents) SetBackupState(selectComponents bool, backupBootableSystemState bool, backupType VssBackup, partialFileSupport bool, ) error { selectComponentsVal := apiBoolToInt(selectComponents) backupBootableSystemStateVal := apiBoolToInt(backupBootableSystemState) partialFileSupportVal := apiBoolToInt(partialFileSupport) result, _, _ := syscall.Syscall6(vss.getVTable().setBackupState, 5, uintptr(unsafe.Pointer(vss)), uintptr(selectComponentsVal), uintptr(backupBootableSystemStateVal), uintptr(backupType), uintptr(partialFileSupportVal), 0) return newVssErrorIfResultNotOK("SetBackupState() failed", HRESULT(result)) } // DoSnapshotSet calls the equivalent VSS api. func (vss *IVssBackupComponents) DoSnapshotSet() (*IVSSAsync, error) { var oleIUnknown *ole.IUnknown result, _, _ := syscall.Syscall(vss.getVTable().doSnapshotSet, 2, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&oleIUnknown)), 0) err := newVssErrorIfResultNotOK("DoSnapshotSet() failed", HRESULT(result)) return vss.convertToVSSAsync(oleIUnknown, err) } // DeleteSnapshots calls the equivalent VSS api. func (vss *IVssBackupComponents) DeleteSnapshots(snapshotID ole.GUID) (int32, ole.GUID, error) { var deletedSnapshots int32 = 0 var nondeletedSnapshotID ole.GUID var result uintptr = 0 if runtime.GOARCH == "386" { id := (*[4]uintptr)(unsafe.Pointer(&snapshotID)) result, _, _ = syscall.Syscall9(vss.getVTable().deleteSnapshots, 9, uintptr(unsafe.Pointer(vss)), id[0], id[1], id[2], id[3], uintptr(VSS_OBJECT_SNAPSHOT), uintptr(1), uintptr(unsafe.Pointer(&deletedSnapshots)), uintptr(unsafe.Pointer(&nondeletedSnapshotID)), ) } else { result, _, _ = syscall.Syscall6(vss.getVTable().deleteSnapshots, 6, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&snapshotID)), uintptr(VSS_OBJECT_SNAPSHOT), uintptr(1), uintptr(unsafe.Pointer(&deletedSnapshots)), uintptr(unsafe.Pointer(&nondeletedSnapshotID))) } err := newVssErrorIfResultNotOK("DeleteSnapshots() failed", HRESULT(result)) return deletedSnapshots, nondeletedSnapshotID, err } // GetSnapshotProperties calls the equivalent VSS api. func (vss *IVssBackupComponents) GetSnapshotProperties(snapshotID ole.GUID, properties *VssSnapshotProperties) error { var result uintptr = 0 if runtime.GOARCH == "386" { id := (*[4]uintptr)(unsafe.Pointer(&snapshotID)) result, _, _ = syscall.Syscall6(vss.getVTable().getSnapshotProperties, 6, uintptr(unsafe.Pointer(vss)), id[0], id[1], id[2], id[3], uintptr(unsafe.Pointer(properties))) } else { result, _, _ = syscall.Syscall(vss.getVTable().getSnapshotProperties, 3, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&snapshotID)), uintptr(unsafe.Pointer(properties))) } return newVssErrorIfResultNotOK("GetSnapshotProperties() failed", HRESULT(result)) } // vssFreeSnapshotProperties calls the equivalent VSS api. func vssFreeSnapshotProperties(properties *VssSnapshotProperties) error { proc, err := findVssProc("VssFreeSnapshotProperties") if err != nil { return err } proc.Call(uintptr(unsafe.Pointer(properties))) return nil } // BackupComplete calls the equivalent VSS api. func (vss *IVssBackupComponents) BackupComplete() (*IVSSAsync, error) { var oleIUnknown *ole.IUnknown result, _, _ := syscall.Syscall(vss.getVTable().backupComplete, 2, uintptr(unsafe.Pointer(vss)), uintptr(unsafe.Pointer(&oleIUnknown)), 0) err := newVssErrorIfResultNotOK("BackupComplete() failed", HRESULT(result)) return vss.convertToVSSAsync(oleIUnknown, err) } // VssSnapshotProperties defines the properties of a VSS snapshot as part of the VSS api. type VssSnapshotProperties struct { snapshotID ole.GUID snapshotSetID ole.GUID snapshotsCount uint32 snapshotDeviceObject *uint16 originalVolumeName *uint16 originatingMachine *uint16 serviceMachine *uint16 exposedName *uint16 exposedPath *uint16 providerID ole.GUID snapshotAttributes uint32 creationTimestamp uint64 status uint } // GetSnapshotDeviceObject returns root path to access the snapshot files // and folders. func (p *VssSnapshotProperties) GetSnapshotDeviceObject() string { return ole.UTF16PtrToString(p.snapshotDeviceObject) } // UIID_IVSS_ASYNC defines to GUID of IVSSAsync. var UIID_IVSS_ASYNC = ole.NewGUID("{507C37B4-CF5B-4e95-B0AF-14EB9767467E}") // IVSSAsync VSS api interface. type IVSSAsync struct { ole.IUnknown } // IVSSAsyncVTable is the vtable for IVSSAsync. type IVSSAsyncVTable struct { ole.IUnknownVtbl cancel uintptr wait uintptr queryStatus uintptr } // Constants for IVSSAsync api. const ( VSS_S_ASYNC_PENDING = 0x00042309 VSS_S_ASYNC_FINISHED = 0x0004230A VSS_S_ASYNC_CANCELLED = 0x0004230B ) // getVTable returns the vtable for IVSSAsync. func (vssAsync *IVSSAsync) getVTable() *IVSSAsyncVTable { return (*IVSSAsyncVTable)(unsafe.Pointer(vssAsync.RawVTable)) } // Cancel calls the equivalent VSS api. func (vssAsync *IVSSAsync) Cancel() HRESULT { result, _, _ := syscall.Syscall(vssAsync.getVTable().cancel, 1, uintptr(unsafe.Pointer(vssAsync)), 0, 0) return HRESULT(result) } // Wait calls the equivalent VSS api. func (vssAsync *IVSSAsync) Wait(millis uint32) HRESULT { result, _, _ := syscall.Syscall(vssAsync.getVTable().wait, 2, uintptr(unsafe.Pointer(vssAsync)), uintptr(millis), 0) return HRESULT(result) } // QueryStatus calls the equivalent VSS api. func (vssAsync *IVSSAsync) QueryStatus() (HRESULT, uint32) { var state uint32 = 0 result, _, _ := syscall.Syscall(vssAsync.getVTable().queryStatus, 3, uintptr(unsafe.Pointer(vssAsync)), uintptr(unsafe.Pointer(&state)), 0) return HRESULT(result), state } // WaitUntilAsyncFinished waits until either the async call is finished or // the given timeout is reached. func (vssAsync *IVSSAsync) WaitUntilAsyncFinished(millis uint32) error { hresult := vssAsync.Wait(millis) err := newVssErrorIfResultNotOK("Wait() failed", hresult) if err != nil { vssAsync.Cancel() return err } hresult, state := vssAsync.QueryStatus() err = newVssErrorIfResultNotOK("QueryStatus() failed", hresult) if err != nil { vssAsync.Cancel() return err } if state == VSS_S_ASYNC_CANCELLED { return newVssTextError("async operation cancelled") } if state == VSS_S_ASYNC_PENDING { vssAsync.Cancel() return newVssTextError("async operation pending") } if state != VSS_S_ASYNC_FINISHED { err = newVssErrorIfResultNotOK("async operation failed", HRESULT(state)) if err != nil { return err } } return nil } // MountPoint wraps all information of a snapshot of a mountpoint on a volume. type MountPoint struct { isSnapshotted bool snapshotSetID ole.GUID snapshotProperties VssSnapshotProperties snapshotDeviceObject string } // IsSnapshotted is true if this mount point was snapshotted successfully. func (p *MountPoint) IsSnapshotted() bool { return p.isSnapshotted } // GetSnapshotDeviceObject returns root path to access the snapshot files and folders. func (p *MountPoint) GetSnapshotDeviceObject() string { return p.snapshotDeviceObject } // VssSnapshot wraps windows volume shadow copy api (vss) via a simple // interface to create and delete a vss snapshot. type VssSnapshot struct { iVssBackupComponents *IVssBackupComponents snapshotID ole.GUID snapshotProperties VssSnapshotProperties snapshotDeviceObject string mountPointInfo map[string]MountPoint timeoutInMillis uint32 } // GetSnapshotDeviceObject returns root path to access the snapshot files // and folders. func (p *VssSnapshot) GetSnapshotDeviceObject() string { return p.snapshotDeviceObject } // initializeCOMInterface initialize an instance of the VSS COM api func initializeVssCOMInterface() (*ole.IUnknown, error) { vssInstance, err := loadIVssBackupComponentsConstructor() if err != nil { return nil, err } // ensure COM is initialized before use ole.CoInitializeEx(0, ole.COINIT_MULTITHREADED) var oleIUnknown *ole.IUnknown result, _, _ := vssInstance.Call(uintptr(unsafe.Pointer(&oleIUnknown))) hresult := HRESULT(result) switch hresult { case S_OK: case E_ACCESSDENIED: return oleIUnknown, newVssError( "The caller does not have sufficient backup privileges or is not an administrator", hresult) default: return oleIUnknown, newVssError("Failed to create VSS instance", hresult) } if oleIUnknown == nil { return nil, newVssError("Failed to initialize COM interface", hresult) } return oleIUnknown, nil } // HasSufficientPrivilegesForVSS returns nil if the user is allowed to use VSS. func HasSufficientPrivilegesForVSS() error { oleIUnknown, err := initializeVssCOMInterface() if oleIUnknown != nil { oleIUnknown.Release() } return err } // NewVssSnapshot creates a new vss snapshot. If creating the snapshots doesn't // finish within the timeout an error is returned. func NewVssSnapshot( volume string, timeoutInSeconds uint, msgError ErrorHandler) (VssSnapshot, error) { is64Bit, err := isRunningOn64BitWindows() if err != nil { return VssSnapshot{}, newVssTextError(fmt.Sprintf( "Failed to detect windows architecture: %s", err.Error())) } if (is64Bit && runtime.GOARCH != "amd64") || (!is64Bit && runtime.GOARCH != "386") { return VssSnapshot{}, newVssTextError(fmt.Sprintf("executables compiled for %s can't use "+ "VSS on other architectures. Please use an executable compiled for your platform.", runtime.GOARCH)) } timeoutInMillis := uint32(timeoutInSeconds * 1000) oleIUnknown, err := initializeVssCOMInterface() if oleIUnknown != nil { defer oleIUnknown.Release() } if err != nil { return VssSnapshot{}, err } comInterface, err := queryInterface(oleIUnknown, UUID_IVSS) if err != nil { return VssSnapshot{}, err } /* https://microsoft.public.win32.programmer.kernel.narkive.com/aObDj2dD/volume-shadow-copy-backupcomplete-and-vss-e-bad-state CreateVSSBackupComponents(); InitializeForBackup(); SetBackupState(); GatherWriterMetadata(); StartSnapshotSet(); AddToSnapshotSet(); PrepareForBackup(); DoSnapshotSet(); GetSnapshotProperties(); VssFreeSnapshotProperties(); BackupComplete(); */ iVssBackupComponents := (*IVssBackupComponents)(unsafe.Pointer(comInterface)) if err := iVssBackupComponents.InitializeForBackup(); err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } if err := iVssBackupComponents.SetContext(VSS_CTX_BACKUP); err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } // see https://techcommunity.microsoft.com/t5/Storage-at-Microsoft/What-is-the-difference-between-VSS-Full-Backup-and-VSS-Copy/ba-p/423575 if err := iVssBackupComponents.SetBackupState(false, false, VSS_BT_COPY, false); err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } err = callAsyncFunctionAndWait(iVssBackupComponents.GatherWriterMetadata, "GatherWriterMetadata", timeoutInMillis) if err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } if isSupported, err := iVssBackupComponents.IsVolumeSupported(volume); err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } else if !isSupported { iVssBackupComponents.Release() return VssSnapshot{}, newVssTextError(fmt.Sprintf("Snapshots are not supported for volume "+ "%s", volume)) } snapshotSetID, err := iVssBackupComponents.StartSnapshotSet() if err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } if err := iVssBackupComponents.AddToSnapshotSet(volume, &snapshotSetID); err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } mountPoints, err := enumerateMountedFolders(volume) if err != nil { iVssBackupComponents.Release() return VssSnapshot{}, newVssTextError(fmt.Sprintf( "failed to enumerate mount points for volume %s: %s", volume, err)) } mountPointInfo := make(map[string]MountPoint) for _, mountPoint := range mountPoints { // ensure every mountpoint is available even without a valid // snapshot because we need to consider this when backing up files mountPointInfo[mountPoint] = MountPoint{isSnapshotted: false} if isSupported, err := iVssBackupComponents.IsVolumeSupported(mountPoint); err != nil { continue } else if !isSupported { continue } var mountPointSnapshotSetID ole.GUID err := iVssBackupComponents.AddToSnapshotSet(mountPoint, &mountPointSnapshotSetID) if err != nil { iVssBackupComponents.Release() return VssSnapshot{}, err } mountPointInfo[mountPoint] = MountPoint{isSnapshotted: true, snapshotSetID: mountPointSnapshotSetID} } err = callAsyncFunctionAndWait(iVssBackupComponents.PrepareForBackup, "PrepareForBackup", timeoutInMillis) if err != nil { // After calling PrepareForBackup one needs to call AbortBackup() before releasing the VSS // instance for proper cleanup. // It is not necessary to call BackupComplete before releasing the VSS instance afterwards. iVssBackupComponents.AbortBackup() iVssBackupComponents.Release() return VssSnapshot{}, err } err = callAsyncFunctionAndWait(iVssBackupComponents.DoSnapshotSet, "DoSnapshotSet", timeoutInMillis) if err != nil { iVssBackupComponents.AbortBackup() iVssBackupComponents.Release() return VssSnapshot{}, err } var snapshotProperties VssSnapshotProperties err = iVssBackupComponents.GetSnapshotProperties(snapshotSetID, &snapshotProperties) if err != nil { iVssBackupComponents.AbortBackup() iVssBackupComponents.Release() return VssSnapshot{}, err } for mountPoint, info := range mountPointInfo { if !info.isSnapshotted { continue } err := iVssBackupComponents.GetSnapshotProperties(info.snapshotSetID, &info.snapshotProperties) if err != nil { msgError(mountPoint, errors.Errorf( "VSS error: GetSnapshotProperties() for mount point %s returned error: ", mountPoint, err)) info.isSnapshotted = false } else { info.snapshotDeviceObject = info.snapshotProperties.GetSnapshotDeviceObject() } mountPointInfo[mountPoint] = info } return VssSnapshot{iVssBackupComponents, snapshotSetID, snapshotProperties, snapshotProperties.GetSnapshotDeviceObject(), mountPointInfo, timeoutInMillis}, nil } // Delete deletes the created snapshot. func (p *VssSnapshot) Delete() error { var err error if err = vssFreeSnapshotProperties(&p.snapshotProperties); err != nil { return err } for _, mountPoint := range p.mountPointInfo { if mountPoint.isSnapshotted { if err = vssFreeSnapshotProperties(&mountPoint.snapshotProperties); err != nil { return err } } } if p.iVssBackupComponents != nil { defer p.iVssBackupComponents.Release() err = callAsyncFunctionAndWait(p.iVssBackupComponents.BackupComplete, "BackupComplete", p.timeoutInMillis) if err != nil { return err } if _, _, e := p.iVssBackupComponents.DeleteSnapshots(p.snapshotID); e != nil { err = newVssTextError(fmt.Sprintf("Failed to delete snapshot: %s", e.Error())) p.iVssBackupComponents.AbortBackup() if err != nil { return err } } } return nil } // asyncCallFunc is the callback type for callAsyncFunctionAndWait. type asyncCallFunc func() (*IVSSAsync, error) // callAsyncFunctionAndWait calls an async functions and waits for it to either // finish or timeout. func callAsyncFunctionAndWait(function asyncCallFunc, name string, timeoutInMillis uint32) error { iVssAsync, err := function() if err != nil { return err } if iVssAsync == nil { return newVssTextError(fmt.Sprintf("%s() returned nil", name)) } err = iVssAsync.WaitUntilAsyncFinished(timeoutInMillis) iVssAsync.Release() return err } // loadIVssBackupComponentsConstructor finds the constructor of the VSS api // inside the VSS dynamic library. func loadIVssBackupComponentsConstructor() (*windows.LazyProc, error) { createInstanceName := "?CreateVssBackupComponents@@YAJPEAPEAVIVssBackupComponents@@@Z" if runtime.GOARCH == "386" { createInstanceName = "?CreateVssBackupComponents@@YGJPAPAVIVssBackupComponents@@@Z" } return findVssProc(createInstanceName) } // findVssProc find a function with the given name inside the VSS api // dynamic library. func findVssProc(procName string) (*windows.LazyProc, error) { vssDll := windows.NewLazySystemDLL("VssApi.dll") err := vssDll.Load() if err != nil { return &windows.LazyProc{}, err } proc := vssDll.NewProc(procName) err = proc.Find() if err != nil { return &windows.LazyProc{}, err } return proc, nil } // queryInterface is a wrapper around the windows QueryInterface api. func queryInterface(oleIUnknown *ole.IUnknown, guid *ole.GUID) (*interface{}, error) { var ivss *interface{} result, _, _ := syscall.Syscall(oleIUnknown.VTable().QueryInterface, 3, uintptr(unsafe.Pointer(oleIUnknown)), uintptr(unsafe.Pointer(guid)), uintptr(unsafe.Pointer(&ivss))) if result != 0 { return nil, newVssError("QueryInterface failed", HRESULT(result)) } return ivss, nil } // isRunningOn64BitWindows returns true if running on 64-bit windows. func isRunningOn64BitWindows() (bool, error) { if runtime.GOARCH == "amd64" { return true, nil } isWow64 := false err := windows.IsWow64Process(windows.CurrentProcess(), &isWow64) if err != nil { return false, err } return isWow64, nil } // enumerateMountedFolders returns all mountpoints on the given volume. func enumerateMountedFolders(volume string) ([]string, error) { var mountedFolders []string volumeNamePointer, err := syscall.UTF16PtrFromString(volume) if err != nil { return mountedFolders, err } volumeMountPointBuffer := make([]uint16, windows.MAX_LONG_PATH) handle, err := windows.FindFirstVolumeMountPoint(volumeNamePointer, &volumeMountPointBuffer[0], windows.MAX_LONG_PATH) if err != nil { // if there are no volumes an error is returned return mountedFolders, nil } defer windows.FindVolumeMountPointClose(handle) volumeMountPoint := syscall.UTF16ToString(volumeMountPointBuffer) mountedFolders = append(mountedFolders, cleanupVolumeMountPoint(volume, volumeMountPoint)) for { err = windows.FindNextVolumeMountPoint(handle, &volumeMountPointBuffer[0], windows.MAX_LONG_PATH) if err != nil { if err == syscall.ERROR_NO_MORE_FILES { break } return mountedFolders, newVssTextError("FindNextVolumeMountPoint() failed: " + err.Error()) } volumeMountPoint := syscall.UTF16ToString(volumeMountPointBuffer) mountedFolders = append(mountedFolders, cleanupVolumeMountPoint(volume, volumeMountPoint)) } return mountedFolders, nil } func cleanupVolumeMountPoint(volume, mountPoint string) string { return strings.ToLower(filepath.Join(volume, mountPoint) + string(filepath.Separator)) }