FUSE Component

Properties Methods Events Config Settings Errors

The FUSE component gives applications the ability to create a virtual filesystem using a FUSE-like API.

Syntax

callback.CBFSConnect.FUSE

Remarks

The FUSE component is used to create a virtual filesystem whose contents are stored and exposed in an application-defined manner. The FUSE component offers applications an API similar to the one used by the FUSE library on Linux.

Getting Started

Each FUSE component instance controls a single virtual filesystem, and therefore a single virtual drive. Applications can use multiple instances of the FUSE component if their use-case requires the creation of multiple virtual drives; the component's Tag property can be used to distinguish between instances during event handlers.

Here's how to get up and running:

If the system driver has not been installed yet, call the Install method to do so. This needs to be done only once.
- In production, the system driver can be installed (or updated) ahead of time by the application's installation script using the Installer DLL (dynamic link library). Please refer to the Driver Installation topic for more information.
Call the Initialize method to initialize the FUSE component. This must be done each time the application starts (if the application is using multiple FUSE component instances, only the first instance created should be used to call Initialize).
Ensure that all of the necessary event handlers have been implemented. Some event handlers, such as Open, Read, GetAttr, and ReadDir, are mandatory and must be implemented by all applications (this is not an exhaustive list). Others are optional, and need to be implemented only when certain features are enabled. Please refer to the events' documentation for more information.
Create a virtual drive by calling the Mount method. This operation incorporates several steps, such as creation of the virtual disk, mounting a "storage media" and adding a mounting point. A mounting point can be a drive letter, a universal naming convention (UNC) path, or a directory on an existing NTFS-formatted drive (see Mounting Points for details).
The application can unmount the "media" from the virtual drive using the Unmount method.
To uninstall the system driver, call the Uninstall method. This should not be done as part of the driver-upgrade process.
- In production, the system driver can be uninstalled by the application's uninstallation script using the Installer DLL. Please refer to the Driver Installation topic for more information.

Property List

The following is the full list of the properties of the component with short descriptions. Click on the links for further details.


AccessDeniedProcesses	Collection of access rules that define which processes may not access the virtual drive.
AccessGrantedProcesses	Collection of access rules that define which processes may access the virtual drive.
ProcessRestrictionsEnabled	Whether process access restrictions are enabled.
SerializeEvents	Whether events should be fired on a single worker thread, or many.
StorageCharacteristics	This property includes the characteristic flags with which to create the virtual drive (Windows only).
Tag	This property stores application-defined data specific to a particular instance of the component.

Method List

The following is the full list of the methods of the component with short descriptions. Click on the links for further details.


AddDeniedProcess	Adds a rule that prevents a process from accessing the virtual drive (Windows only).
AddGrantedProcess	Adds a rule that allows a process to access the virtual drive (Windows only).
Config	Sets or retrieves a configuration setting.
FileTimeToNanoseconds	This method returns the subsecond part of the time expressed in nanoseconds.
FileTimeToUnixTime	This method converts FileTime to the Unix time format.
FillDir	This method fills the buffer with information about a directory entry.
GetDriverStatus	This method retrieves the status of the system driver.
GetDriverVersion	This method retrieves the version of the system driver.
GetGid	This method returns the group Id of the caller process.
GetOriginatorProcessId	Retrieves the Id of the process (PID) that initiated the operation (Windows only).
GetOriginatorProcessName	Retrieves the name of the process that initiated the operation (Windows only).
GetOriginatorThreadId	Retrieves the Id of the thread that initiated the operation (Windows only).
GetOriginatorToken	Retrieves the security token associated with the process that initiated the operation (Windows only).
GetUid	The method returns the user Id of the caller process.
Initialize	This method initializes the component.
Install	This method installs or upgrades the product's system drivers (Windows only).
Mount	This method creates a virtual drive or directory and mounts a filesystem.
RemoveDeniedProcess	Removes a rule that prevents a process from accessing the virtual drive (Windows only).
RemoveGrantedProcess	Removes a rule that allows a process to access the virtual drive (Windows only).
Uninstall	Uninstalls the product's system drivers and/or helper DLL (Windows only).
UnixTimeToFileTime	This event converts the date/time in Unix format to Windows FileTime format.
Unmount	This method unmounts a filesystem.

Event List

The following is the full list of the events fired by the component with short descriptions. Click on the links for further details.


Access	This event fires when the OS needs to check file access permissions.
Chmod	This event fires when the OS needs to change the permission bits of a file.
Chown	This event fires when the OS needs to change the owner and group of a file.
CopyFileRange	This event fires when the OS needs to copy a range of data from one file to another.
Create	This event fires when the OS wants to create a file.
Destroy	This event fires upon filesystem exit.
Error	This event fires if an unhandled error occurs during an event.
FAllocate	This event fires when the OS needs to allocate space for an open file.
Flush	This event fires when the OS needs to flush an open file's data out to storage before the file is closed.
FSync	This event fires when the OS needs to flush an open file's data out to storage.
GetAttr	This event fires when the OS needs information about a file or directory.
Init	This event fires on filesystem startup.
Lock	This event fires when the OS needs to lock or unlock the range of bytes of a file.
MkDir	This event fires when the OS needs to create a directory.
Open	This event fires when the OS wants to open a file.
Read	This event fires when the OS needs to read data from an open file.
ReadDir	This event fires when the OS wants to read (enumerate) a directory's contents.
Release	This event fires when the OS needs to release (close) a file.
Rename	This event fires when the OS wants to rename or move a file or directory within the virtual filesystem.
RmDir	This event fires when the OS wants to remove (delete) a directory.
StatFS	This event fires when the OS needs information about the virtual drive's capacity and free space.
Truncate	This event fires when the OS needs to truncate (set the size of) a file.
Unlink	This event fires when the OS wants to unlink (delete) a file.
UTime	This event fires when the OS needs to change access and modification times of a file.
Write	This event fires when the OS needs to write data to an open file.

Config Settings

The following is a list of config settings for the component with short descriptions. Click on the links for further details.


AsyncMountingPointNotifications	Whether system broadcasts for virtual drive mounting and unmounting are sent asynchronously.
ForceFileClose	Whether the driver should force files to close after the last handle to them is closed (Windows only).
ForceFileCloseDelay	Specifies the timeout between the closing of a last handle of a file and the moment the driver tries to close the file.
LinuxFUSEParams	A placeholder for additional parameters used for fine-tuning FUSE on Linux.
MaxWorkerThreadCount	The maximum number of worker threads to use to fire events.
MetadataCacheEnabled	Whether or not the metadata cache should be used.
MinWorkerThreadCount	The minimum number of worker threads to use to fire events.
NonExistentFilesCacheEnabled	Whether or not the nonexistent files cache should be used.
Timeout	Specifies how many milliseconds the driver will wait for events to execute before cancelling the underlying OS requests. (Windows-only).
TranslateDOSCharsInEnumMasks	Whether the DOS wildcard characters should be translated during search.
WindowsVolumeLabel	A human-readable label for the volume in Windows.
WorkerInitialStackSize	The initial stack size to create worker threads with.
BuildInfo	Information about the product's build.
LicenseInfo	Information about the current license.

AccessDeniedProcesses Property (FUSE Component)

Collection of access rules that define which processes may not access the virtual drive.

public ProcessAccessRuleList AccessDeniedProcesses { get; }

Public ReadOnly Property AccessDeniedProcesses As ProcessAccessRuleList

Remarks

This property holds a collection of ProcessAccessRule objects representing rules that deny processes certain kinds of access to the virtual drive.

Please refer to the AddDeniedProcess and RemoveDeniedProcess methods for more information.

Note: The methods and properties related to process access lists are not intended to be used from multiple threads at once. Applications that wish to use said methods and properties from multiple threads are responsible for employing proper thread synchronization techniques to ensure that manipulation and enumeration of process access information occurs in a thread-safe manner.

This property is read-only and not available at design time.

Please refer to the ProcessAccessRule type for a complete list of fields.

AccessGrantedProcesses Property (FUSE Component)

Collection of access rules that define which processes may access the virtual drive.

Syntax

C#
VB.NET

public ProcessAccessRuleList AccessGrantedProcesses { get; }

Public ReadOnly Property AccessGrantedProcesses As ProcessAccessRuleList

Remarks

This property holds a collection of ProcessAccessRule objects representing rules that grant processes certain kinds of access to the virtual drive.

Please refer to the AddGrantedProcess and RemoveGrantedProcess methods for more information.

This property is read-only and not available at design time.

Please refer to the ProcessAccessRule type for a complete list of fields.

ProcessRestrictionsEnabled Property (FUSE Component)

Whether process access restrictions are enabled.

Syntax

C#
VB.NET

public bool ProcessRestrictionsEnabled { get; set; }

Public Property ProcessRestrictionsEnabled As Boolean

Default Value

False

Remarks

This property controls whether the component should enforce per-process access restrictions; by default, it is disabled. When enabled, the AddGrantedProcess and AddDeniedProcess methods can be used to add process-specific access rules for the component to enforce across the entire virtual drive.

When an application enables this propery, it should use the AddGrantedProcess method to add at least one pocess as allowed; otherwise, the data will be inaccessible.

The current process access rules are reflected by the AccessGrantedProcesses and AccessDeniedProcesses collection properties.

SerializeEvents Property (FUSE Component)

Whether events should be fired on a single worker thread, or many.

Syntax

C#
VB.NET

public FUSESerializeEvents SerializeEvents { get; set; }

enum FUSESerializeEvents {
  seOnMultipleThreads,
  seOnOneWorkerThread
}

Public Property SerializeEvents As FuseSerializeEvents

Enum FUSESerializeEvents
  seOnMultipleThreads
  seOnOneWorkerThread
End Enum

Default Value

Remarks

This property specifies whether the component should fire all events serially on a single worker thread, or concurrently on multiple worker threads. The possible values are:


0 (seOnMultipleThreads)	The component fires events in the context of multiple worker threads. Windows: The MinWorkerThreadCount and MaxWorkerThreadCount configuration settings control how many worker threads are used for this.
1 (seOnOneWorkerThread)	The component fires events in the context of one background worker thread.

Windows: in general, the component will always fire events related to a single file sequentially (though not necessarily on the same worker thread all the time), regardless of how this property is set. Please refer to the Threading and Concurrency topic for more information.

Linux: with this property set to seOnMultipleThreads, the component may fire events related to the same file concurrently in several threads. If the application doesn't support this, it should stick to the seOnOneWorkerThread mode.

Note: This property cannot be changed when Active is true, and it cannot be changed within events.

StorageCharacteristics Property (FUSE Component)

This property includes the characteristic flags with which to create the virtual drive (Windows only).

Syntax

C#
VB.NET

public int StorageCharacteristics { get; set; }

Public Property StorageCharacteristics As Integer

Default Value

Remarks

The system, as well as other applications, uses these flags to optimize their use of the virtual drive. This property should be set by ORing together zero or more of the following flags:


STGC_FLOPPY_DISKETTE	`0x00000001`	The storage is a floppy disk device. This flag is not supported when StorageType is set to `STGT_DISK_PNP`.
STGC_READONLY_DEVICE	`0x00000002`	The storage is a read-only device.
STGC_WRITE_ONCE_MEDIA	`0x00000008`	The storage device's media can only be written to once. This flag is not supported when StorageType is set to `STGT_DISK_PNP`.
STGC_REMOVABLE_MEDIA	`0x00000010`	The storage device's media is removable. Users may remove the storage media from the virtual drive at any time. (Note that this flag does not indicate that the virtual drive itself is removable.)
STGC_AUTOCREATE_DRIVE_LETTER	`0x00002000`	The system should automatically create a drive letter for the storage device. *Deprecated:* Include the `STGMP_AUTOCREATE_DRIVE_LETTER` flag in the value passed for the AddMountingPoint method's `Flags` parameter instead. When this flag is present, the StorageGUID property must be set. This flag only works when StorageType is set to `STGT_DISK_PNP`.
STGC_SHOW_IN_EJECTION_TRAY	`0x00004000`	The storage device should be shown in the 'Safely Remove Hardware and Eject Media' menu in the system notification area (system tray). This flag only works when StorageType is set to `STGT_DISK_PNP`.
STGC_ALLOW_EJECTION	`0x00008000`	The storage device can be ejected. Users may eject the virtual drive at any time. When the virtual drive is ejected, it is destroyed. This flag only works when StorageType is set to `STGT_DISK_PNP`.
STGC_RESERVED_1	`0x00010000`	Reserved, do not use.
STGC_RESERVED_2	`0x00020000`	Reserved, do not use.

Note: This property cannot be changed when the drive is mounted and cannot be changed within events.

Tag Property (FUSE Component)

This property stores application-defined data specific to a particular instance of the component.

Syntax

C#
VB.NET

public long Tag { get; set; }

Public Property Tag As Long

Default Value

Remarks

This property can be used to store data specific to a particular instance of the component.

AddDeniedProcess Method (FUSE Component)

Adds a rule that prevents a process from accessing the virtual drive (Windows only).

Syntax

C#
VB.NET

public void AddDeniedProcess(string processFileName, int processId, bool childProcesses, int desiredAccess);

Public Sub AddDeniedProcess(ByVal ProcessFileName As String, ByVal ProcessId As Integer, ByVal ChildProcesses As Boolean, ByVal DesiredAccess As Integer)

Remarks

When the ProcessRestrictionsEnabled property is enabled, this method can be used to add an access rule that denies the process specified by ProcessFileName or ProcessId the access right specified by DesiredAccess.

Processes that are already running can be specified by passing their process Id (PID) for the ProcessId parameter (in which case ProcessFileName should be empty). Processes that have not yet started can be specified by passing the full file name of the process's executable file for ProcessFileName (in which case ProcessId should be set to 0). If ProcessName is empty, and ProcessId is -1, the new rule will apply to all processes. When adding a PID-based rule, you need to be aware of the PID Reuse behavior of Windows.

ChildProcesses controls whether the rule also applies to children of the target process.

DesiredAccess specifies the access right to deny; valid values are:


STG_DACCESS_READ	`0x00000001`	Grant/deny read access.
STG_DACCESS_WRITE	`0x00000002`	Grant/deny write access.
STG_DACCESS_READWRITE	`0x00000003`	Grant/deny read and write access.

To remove the process access rule later, pass the same ProcessFileName and ProcessId values to the RemoveDeniedProcess method.

Note: This method can be called only when Active is true, and it cannot be called within events.

The methods and properties related to process access lists are not intended to be used from multiple threads at once. Applications that wish to use said methods and properties from multiple threads are responsible for employing proper thread synchronization techniques to ensure that manipulation and enumeration of process access information occurs in a thread-safe manner.

AddGrantedProcess Method (FUSE Component)

Adds a rule that allows a process to access the virtual drive (Windows only).

Syntax

C#
VB.NET

public void AddGrantedProcess(string processFileName, int processId, bool childProcesses, int desiredAccess);

Public Sub AddGrantedProcess(ByVal ProcessFileName As String, ByVal ProcessId As Integer, ByVal ChildProcesses As Boolean, ByVal DesiredAccess As Integer)

Remarks

When the ProcessRestrictionsEnabled property is enabled, this method can be used to add an access rule that grants the process specified by ProcessFileName or ProcessId the access right specified by DesiredAccess.

ChildProcesses controls whether the rule also applies to children of the target process.

DesiredAccess specifies the access right to grant; valid values are:


STG_DACCESS_READ	`0x00000001`	Grant/deny read access.
STG_DACCESS_WRITE	`0x00000002`	Grant/deny write access.
STG_DACCESS_READWRITE	`0x00000003`	Grant/deny read and write access.

To remove the process access rule later, pass the same ProcessFileName and ProcessId values to the RemoveGrantedProcess method.

Note: This method can be called only when Active is true, and it cannot be called within events.

Config Method (FUSE Component)

Sets or retrieves a configuration setting.

Syntax

C#
VB.NET

public string Config(string configurationString);

Public Function Config(ByVal ConfigurationString As String) As String

Remarks

Config is a generic method available in every component. It is used to set and retrieve configuration settings for the component.

These settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

To set a configuration setting named PROPERTY, you must call Config("PROPERTY=VALUE"), where VALUE is the value of the setting expressed as a string. For boolean values, use the strings "True", "False", "0", "1", "Yes", or "No" (case does not matter).

To read (query) the value of a configuration setting, you must call Config("PROPERTY"). The value will be returned as a string.

FileTimeToNanoseconds Method (FUSE Component)

This method returns the subsecond part of the time expressed in nanoseconds.

Syntax

C#
VB.NET

public int FileTimeToNanoseconds(DateTime fileTime);

Public Function FileTimeToNanoseconds(ByVal FileTime As DateTime) As Integer

Remarks

Use this method to obtain the subsecond part of the FileTime value, expressed in nanoseconds.

FileTimeToUnixTime Method (FUSE Component)

This method converts FileTime to the Unix time format.

Syntax

C#
VB.NET

public long FileTimeToUnixTime(DateTime fileTime);

Public Function FileTimeToUnixTime(ByVal FileTime As DateTime) As Long

Remarks

Use this method to convert the FileTime value to the Unix time format. The subsecond part of the value is not preserved; to obtain it, use the FileTimeToNanoseconds method.

FillDir Method (FUSE Component)

This method fills the buffer with information about a directory entry.

Syntax

C#
VB.NET

public int FillDir(long fillerContext, string name, long ino, int mode, int uid, int gid, int linkCount, long size, DateTime ATime, DateTime MTime, DateTime CTime);

Public Function FillDir(ByVal FillerContext As Long, ByVal Name As String, ByVal Ino As Long, ByVal Mode As Integer, ByVal Uid As Integer, ByVal Gid As Integer, ByVal LinkCount As Integer, ByVal Size As Long, ByVal ATime As DateTime, ByVal MTime As DateTime, ByVal CTime As DateTime) As Integer

Remarks

Use the FillDir method from the ReadDir event handler to fill the buffer with the information about a file.

Call the method in a loop to add multiple entries.

The FillerContext parameter is passed to the ReadDir event handler and must be passed by the event handler to this method without modifications.

The Name parameter should contain the name of the directory entry.

The Ino parameter should be set to the Id of the file, which must be unique within a filesystem. Ino is optional on Windows and is ignored on Linux, where FUSE internally generates internal Ids.

The Mode parameter is a combination of bit flags.

Windows: Mode may include 0x4000 (S_IFDIR) to indicate that the entry is a directory, and it must include either 0x80 (S_IWUSR) to indicate a file that can be read and written or 0x100 (S_IRUSR) to indicate a read-only file. Other flags are ignored.

Linux: Mode may include any appropriate file mode flags. See inode(7) for more information.

Windows: The Uid, Gid, and LinkCount parameters are not used.

Linux: The Uid and Gid parameters must be set to the owner's user Id and group Id, respectively. LinkCount should be set to the number of hard links that the file has (which usually is 1).

Size must be set to the size of the file's data. For directories, the parameter should be set to 0.

ATime, MTime, CTime: Set, respectively, to the Access Time, Modification Time, and Creation Time values of the file or directory. All date/time parameters in the component are specified in UTC.

To convert Unix time to a format suitable for this function, use the UnixTimeToFileTime method.

Windows:

Any nonapplicable time values can be set to January 1, 1601 00:00:00 UTC.

The method returns 0 on success and sends an error code otherwise.

Note: This method cannot be called within events.

GetDriverStatus Method (FUSE Component)

This method retrieves the status of the system driver.

Syntax

C#
VB.NET

public int GetDriverStatus(string productGUID);

Public Function GetDriverStatus(ByVal ProductGUID As String) As Integer

Remarks

Windows:

This method retrieves the status of the system driver. This status can then be used to verify whether it has been properly installed and is ready for use.

The value returned by the method corresponds to the dwCurrentState field of the SERVICE_STATUS structure from the Windows API. It will be one of the following:


MODULE_STATUS_NOT_PRESENT	`0x00000000`	The specified module is not present on the system. Note: This functionality is only available in Windows.
MODULE_STATUS_STOPPED	`0x00000001`	The specified module is in the Stopped state. Note: This functionality is only available in Windows.
MODULE_STATUS_RUNNING	`0x00000004`	The specified module is loaded and running. Note: This functionality is only available in Windows.

ProductGUID is used to distinguish between driver installations performed by different applications. Such information is necessary to guard against unexpected situations such as, e.g., the driver being uninstalled by one application despite other applications still needing it.

The GUID must be specified in so-called "Registry Format" (e.g., "{1FAD0EF2-9A03-4B87-B4BC-645B7035ED90}") with curly braces included.

To ensure proper operation, it is critical that each individual application have its own unique ProductGUID value, and that applications (and their installation scripts) use that value when calling any of the following methods:

Install
Uninstall
GetDriverStatus
GetModuleVersion
RegisterIcon
UnregisterIcon
Initialize

This method is available in both the component API and the Installer DLL included with the product; please refer to the Driver Installation topic for more information about the latter.

Note: This method cannot be called within events.

Linux:

This method currently is not used.

GetDriverVersion Method (FUSE Component)

This method retrieves the version of the system driver.

Syntax

C#
VB.NET

public long GetDriverVersion(string productGUID);

Public Function GetDriverVersion(ByVal ProductGUID As String) As Long

Remarks

This method retrieves the version of the system driver. The value is returned as a 64-bit integer composed of four 16-bit words that each correspond to a piece of the overall module version. For example, a version of 2.32.6.28 would cause the value 0x000200200006001C to be returned.

If the driver is not installed, this method returns 0.

The GUID must be specified in so-called "Registry Format" (e.g., "{1FAD0EF2-9A03-4B87-B4BC-645B7035ED90}") with curly braces included.

Install
Uninstall
GetDriverStatus
GetModuleVersion
RegisterIcon
UnregisterIcon
Initialize

This method is available in both the component API and the Installer DLL included with the product; please refer to the Driver Installation topic for more information about the latter.

Note: This method cannot be called within events.

GetGid Method (FUSE Component)

This method returns the group Id of the caller process.

Syntax

C#
VB.NET

public int GetGid();

Public Function GetGid() As Integer

Remarks

Windows:

This method currently is not used.

Linux:

Call this method from the event handlers to obtain the group Id of the caller process.

GetOriginatorProcessId Method (FUSE Component)

Retrieves the Id of the process (PID) that initiated the operation (Windows only).

Syntax

C#
VB.NET

public int GetOriginatorProcessId();

Public Function GetOriginatorProcessId() As Integer

Remarks

This method can be called within certain events to retrieve the Id of the process (PID) that initiated the operation. If the query fails, this method returns 0.

Please note that PIDs are not unique, and may be reused by different processes over time (though in practice, this is uncommon).

Applications cannot use this method to retrieve information about remote processes accessing virtual drives shared on the network. Windows does not provide such information due to the nature of remote access.

Note: This method can be called only within events, and it must be called in the same thread that the event was originally fired on. However, it must not be called within events that work with opened files , such as ReadFile and WriteFile, since such events can be initiated by system components (e.g., the cache manager, memory manager, etc.). If applications need the information this method returns during such events, they may do the following:

Call this method within the CreateFile or OpenFile event.
Store the information somewhere, and store a reference to it in the event's HandleContext parameter.
In a later event, access the information via the reference stored in HandleContext.

Please refer to the Contexts topic for more information on how to use events' context parameters.

Note: Renaming and deletion of files is performed after the file is opened. Thus, access checks should be performed during file opening as described above.

GetOriginatorProcessName Method (FUSE Component)

Retrieves the name of the process that initiated the operation (Windows only).

Syntax

C#
VB.NET

public string GetOriginatorProcessName();

Public Function GetOriginatorProcessName() As String

Remarks

This method can be called within certain events to retrieve the name of the process that initiated the operation. If the query fails, this method returns empty string.

Call this method within the CreateFile or OpenFile event.
Store the information somewhere, and store a reference to it in the event's HandleContext parameter.
In a later event, access the information via the reference stored in HandleContext.

Please refer to the Contexts topic for more information on how to use events' context parameters.

Note: Renaming and deletion of files is performed after the file is opened. Thus, access checks should be performed during file opening as described above.

GetOriginatorThreadId Method (FUSE Component)

Retrieves the Id of the thread that initiated the operation (Windows only).

Syntax

C#
VB.NET

public int GetOriginatorThreadId();

Public Function GetOriginatorThreadId() As Integer

Remarks

This method can be called within certain events to retrieve the Id of the thread that initiated the operation. If the query fails, this method returns 0.

Please note that thread Ids are not unique, and may be reused by different threads over time.

Call this method within the CreateFile or OpenFile event.
Store the information somewhere, and store a reference to it in the event's HandleContext parameter.
In a later event, access the information via the reference stored in HandleContext.

Please refer to the Contexts topic for more information on how to use events' context parameters.

Note: Renaming and deletion of files is performed after the file is opened. Thus, access checks should be performed during file opening as described above.

GetOriginatorToken Method (FUSE Component)

Retrieves the security token associated with the process that initiated the operation (Windows only).

Syntax

C#
VB.NET

public long GetOriginatorToken();

Public Function GetOriginatorToken() As Long

Remarks

This method can be called within certain events to retrieve the security token associated with the process that initiated the operation. If the query fails, this method returns INVALID_HANDLE_VALUE.

The security token returned by this method can be passed to the Windows API's GetTokenInformation function to obtain more information about the process. This is particularly useful for implementing custom security checks; please refer to the Security Checks topic for more information.

Important: When applications are finished using the returned security token, they must close it using the Windows API's CloseHandle function.

Network Access Notes

For virtual drives shared on the network, applications may wish to obtain information about the network users accessing it (e.g., account names). Drives can be shared in several modes in Windows, which can affect the information retrievable via the security token this method returns:

Authenticated mode, in which case the Helper DLL (which, in general, is responsible for relaying remote drive requests to and from the system driver) will impersonate the network user, allowing that account's actual information to be retrieved.
Guest mode, in which case the retrievable information is for the system's GUEST account.
Administrative shares (those which exist by default and whose names end with '$'; e.g., C$, ADMIN$, etc.), in which case the retrievable information is for the LOCAL_SYSTEM account.

Call this method within the CreateFile or OpenFile event.
Store the information somewhere, and store a reference to it in the event's HandleContext parameter.
In a later event, access the information via the reference stored in HandleContext.

Please refer to the Contexts topic for more information on how to use events' context parameters.

Note: Renaming and deletion of files is performed after the file is opened. Thus, access checks should be performed during file opening as described above.

GetUid Method (FUSE Component)

The method returns the user Id of the caller process.

Syntax

C#
VB.NET

public int GetUid();

Public Function GetUid() As Integer

Remarks

Windows:

This method currently is not used.

Linux:

Call this method from the event handlers to obtain the user Id of the caller process.

Initialize Method (FUSE Component)

This method initializes the component.

Syntax

C#
VB.NET

public void Initialize(string productGUID);

Public Sub Initialize(ByVal ProductGUID As String)

Remarks

This method initializes the component and must be called each time the application starts before attempting to call any of the component's other methods with the exception of installation-related methods.

The GUID must be specified in so-called "Registry Format" (e.g., "{1FAD0EF2-9A03-4B87-B4BC-645B7035ED90}") with curly braces included.

Install
Uninstall
GetDriverStatus
GetModuleVersion
RegisterIcon
UnregisterIcon
Initialize

If the required driver was not installed using the Install method with the same value of ProductGUID, Initialize will return a ERROR_FILE_NOT_FOUND error (Win32 error code 2).

If the loaded kernel-mode driver is older than the user-mode API, Initialize will return a ERROR_INVALID_KERNEL_INFO_VERSION error (Win32 error code 340). In this situation, an update of the driver using the Install method is required before the component can be used.

Install Method (FUSE Component)

This method installs or upgrades the product's system drivers (Windows only).

Syntax

C#
VB.NET

public int Install(string cabFileName, string productGUID, string pathToInstall, int flags);

Public Function Install(ByVal CabFileName As String, ByVal ProductGUID As String, ByVal PathToInstall As String, ByVal Flags As Integer) As Integer

Remarks

Windows:

This method is used to install or upgrade the product's system driver. If the system must be rebooted to complete the installation process, this method will return a nonzero value.

Important: To upgrade the product's modules, use only the Install method. Previously installed versions of the modules should not be uninstalled first. Calling the Install method will upgrade the previously installed version.

Please refer to the Driver Installation topic for more information.

CabFileName must be the path of the .cab file containing the product modules.

Note: This .cab file must remain on the target system (or be available in some other way) after installation, because it is required to uninstall the modules from the system.

The GUID must be specified in so-called "Registry Format" (e.g., "{1FAD0EF2-9A03-4B87-B4BC-645B7035ED90}") with curly braces included.

Install
Uninstall
GetDriverStatus
GetModuleVersion
RegisterIcon
UnregisterIcon
Initialize

PathToInstall controls where the modules are installed. Pass an empty string (highly recommended) to automatically install them to the appropriate Windows system directory.

Flags specifies various installation options and should contain zero or more of the following flags, ORed together:


INSTALL_REMOVE_OLD_VERSIONS	`0x00000001`	Uninstall drivers and helper DLLs from previous component versions (e.g., 2017). Note: This functionality is only available in Windows. This flag does not remove the old PnP driver (VPnpBus) from the system because that driver is not versioned. Use the installer DLL of the old version and its Uninstall() function if you need to uninstall the PnP driver.
INSTALL_KEEP_START_TYPE	`0x00000002`	Keep the driver's current start type setting in the registry. If this flag is not set (default), the installation logic will reset the driver's start type setting in the Windows registry to the default value. Setting this flag causes the installation logic to preserve the current value, which may be necessary if the user (or the application itself) set it previously. Note: This functionality is only available in Windows.
INSTALL_OVERWRITE_SAME_VERSION	`0x00000004`	Install files when their version is the same as the version of already installed files. If this flag is not set (default), the installation logic will overwrite the existing file only if the version number of the file being installed is larger than the version of the file being overwritten. Setting this flag causes the installation logic to overwrite the file even when it has the same version. Note: This functionality is only available in Windows.

This method is available in both the component API and the Installer DLL included with the product; please refer to the Driver Installation topic for more information about the latter.

This method requires administrative rights to execute successfully. If the user account of the process that calls this method doesn't have such rights, the call will fail with an ERROR_PRIVILEGE_NOT_HELD (0x0522) error.

Note: This method cannot be called within events.

Linux:

This method currently is not used.

Mount Method (FUSE Component)

This method creates a virtual drive or directory and mounts a filesystem.

Syntax

C#
VB.NET

public void Mount(string mountPoint);

Public Sub Mount(ByVal MountPoint As String)

Remarks

Call this method to create a virtual drive or directory and mount a filesystem.

The MountPoint parameter contains a path to the directory, into which the virtual filesystem is "inserted". This path must exist at the time of mounting and must be empty.

Windows:

The MountPoint parameter may also contain a drive letter or a UNC path; please refer to the Mounting Points topic for more information.

RemoveDeniedProcess Method (FUSE Component)

Removes a rule that prevents a process from accessing the virtual drive (Windows only).

Syntax

C#
VB.NET

public void RemoveDeniedProcess(string processFileName, int processId);

Public Sub RemoveDeniedProcess(ByVal ProcessFileName As String, ByVal ProcessId As Integer)

Remarks

When the ProcessRestrictionsEnabled property is enabled, this method can be used to remove an access rule previously added with the AddDeniedProcess method.

Pass the same values for ProcessFileName and ProcessId as were used to add the rule when AddDeniedProcess was called previously. Please refer to that method's documentation for more information.

Note: This method can be called only when Active is true, and it cannot be called within events.

RemoveGrantedProcess Method (FUSE Component)

Removes a rule that allows a process to access the virtual drive (Windows only).

Syntax

C#
VB.NET

public void RemoveGrantedProcess(string processFileName, int processId);

Public Sub RemoveGrantedProcess(ByVal ProcessFileName As String, ByVal ProcessId As Integer)

Remarks

When the ProcessRestrictionsEnabled property is enabled, this method can be used to remove an access rule previously added with the AddGrantedProcess method.

Pass the same values for ProcessFileName and ProcessId as were used to add the rule when AddGrantedProcess was called previously. Please refer to that method's documentation for more information.

Note: This method can be called only when Active is true, and it cannot be called within events.

Uninstall Method (FUSE Component)

Uninstalls the product's system drivers and/or helper DLL (Windows only).

Syntax

C#
VB.NET

public int Uninstall(string cabFileName, string productGUID, string installedPath, int flags);

Public Function Uninstall(ByVal CabFileName As String, ByVal ProductGUID As String, ByVal InstalledPath As String, ByVal Flags As Integer) As Integer

Remarks

This method is used to uninstall the product's various modules (i.e., the system drivers and Helper DLL). If the system must be rebooted to complete the uninstallation process, this method will return a non-zero value indicating which module(s) requested the reboot (see Install for possible values).

Please refer to the Driver Installation topic for more information.

The same values must be passed for the CabFileName, ProductGUID, and InstalledPath parameters as were passed when Install was called; please refer to its documentation for more information.

Flags specifies which versions of the product's modules should be uninstalled, and should be set by OR'ing together one or more of the following values:


UNINSTALL_VERSION_PREVIOUS	`0x00000001`	Uninstall modules from previous product versions. Note: This functionality is only available in Windows.
UNINSTALL_VERSION_CURRENT	`0x00000002`	Uninstall modules from the current product version. Note: This functionality is only available in Windows.
UNINSTALL_VERSION_ALL	`0x00000003`	Uninstall modules from all product versions. Note: This functionality is only available in Windows.

This method is available in both the component API and the Installer DLL included with the product; please refer to the Driver Installation topic for more information about the latter.

Note: This method cannot be called within events.

UnixTimeToFileTime Method (FUSE Component)

This event converts the date/time in Unix format to Windows FileTime format.

Syntax

C#
VB.NET

public DateTime UnixTimeToFileTime(long unixTime, int nanoseconds);

Public Function UnixTimeToFileTime(ByVal UnixTime As Long, ByVal Nanoseconds As Integer) As DateTime

Remarks

Use this method to convert the date/time in Unix format to Windows FileTime format.

Pass the Unix time value to UnixTime and optionally pass the subsecond part of the time, expressed in nanoseconds, to the Nanoseconds parameter. If the subsecond part of the time is not available, set Nanoseconds to zero (0) value.

Unmount Method (FUSE Component)

This method unmounts a filesystem.

Syntax

C#
VB.NET

public void Unmount();

Public Sub Unmount()

Remarks

This method unmounts the mounted filesystem and deletes a virtual device from the system.

Access Event (FUSE Component)

This event fires when the OS needs to check file access permissions.

Syntax

C#
VB.NET

public event OnAccessHandler OnAccess;

public delegate void OnAccessHandler(object sender, FUSEAccessEventArgs e);

public class FUSEAccessEventArgs : EventArgs {
  public string Path { get; }
  public int Mask { get; }
  public int Result { get; set; }
}

Public Event OnAccess As OnAccessHandler

Public Delegate Sub OnAccessHandler(sender As Object, e As FUSEAccessEventArgs)

Public Class FUSEAccessEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property Mask As Integer
  Public Property Result As Integer
End Class

Remarks

Windows:

This event fires when the OS needs to know whether the file or directory specified in Path can be deleted. For this, the Mask parameter is set to 2 (W_OK).

The application must return 0 in the Result parameter to indicate that deletion is permitted, or otherwise sends an error code.

Linux:

This event fires when the OS needs to check access permissions of the file or directory specified in Path. Specifically, the event fires when a process uses the access() system call.

The application must return 0 in the Result parameter to indicate that access requested by the Mask parameter is permitted, or otherwise sends -EACCES< to indicate that access is denied.

If the event cannot be handled in a "successful" manner for some reason (e.g., a resource is not available, or security checks failed), set it to a negative error code value (e.g., -ENOENT to indicate that the file does not exist) to report an appropriate error. Please refer to the Error Handling topic for more information.

Chmod Event (FUSE Component)

This event fires when the OS needs to change the permission bits of a file.

Syntax

C#
VB.NET

public event OnChmodHandler OnChmod;

public delegate void OnChmodHandler(object sender, FUSEChmodEventArgs e);

public class FUSEChmodEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int Mode { get; }
  public int Result { get; set; }
}

Public Event OnChmod As OnChmodHandler

Public Delegate Sub OnChmodHandler(sender As Object, e As FUSEChmodEventArgs)

Public Class FUSEChmodEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property Mode As Integer
  Public Property Result As Integer
End Class

Remarks

Windows:

This event is not used.

Linux:

This event fires when the OS needs to change the permission bits of a file or directory and is identified either by Path or FileContext.

Mode contains the new permission bits.

The ResultCode parameter will always be 0 when the event is fired. If the event cannot be handled in a "successful" manner for some reason (e.g., a resource is not available, or security checks failed), set it to a negative error code value (e.g., -ENOENT to indicate that the file does not exist) to report an appropriate error. Please refer to the Error Handling topic for more information.

Chown Event (FUSE Component)

This event fires when the OS needs to change the owner and group of a file.

Syntax

C#
VB.NET

public event OnChownHandler OnChown;

public delegate void OnChownHandler(object sender, FUSEChownEventArgs e);

public class FUSEChownEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int Uid { get; }
  public int Gid { get; }
  public int Result { get; set; }
}

Public Event OnChown As OnChownHandler

Public Delegate Sub OnChownHandler(sender As Object, e As FUSEChownEventArgs)

Public Class FUSEChownEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property Uid As Integer
  Public ReadOnly Property Gid As Integer
  Public Property Result As Integer
End Class

Remarks

Windows:

This event currently is not used.

Linux:

This event fires when the OS needs to change the owner and group of a file or directory and is identified by either Path or FileContext.

Uid and Gid contain the new owner Id and group Id, respectively.

CopyFileRange Event (FUSE Component)

This event fires when the OS needs to copy a range of data from one file to another.

Syntax

C#
VB.NET

public event OnCopyFileRangeHandler OnCopyFileRange;

public delegate void OnCopyFileRangeHandler(object sender, FUSECopyFileRangeEventArgs e);

public class FUSECopyFileRangeEventArgs : EventArgs {
  public string PathIn { get; }
  public IntPtr FileContextIn { get; }
  public long OffsetIn { get; }
  public string PathOut { get; }
  public IntPtr FileContextOut { get; }
  public long OffsetOut { get; }
  public long Size { get; }
  public int Flags { get; }
  public int Result { get; set; }
}

Public Event OnCopyFileRange As OnCopyFileRangeHandler

Public Delegate Sub OnCopyFileRangeHandler(sender As Object, e As FUSECopyFileRangeEventArgs)

Public Class FUSECopyFileRangeEventArgs Inherits EventArgs
  Public ReadOnly Property PathIn As String
  Public ReadOnly Property FileContextIn As IntPtr
  Public ReadOnly Property OffsetIn As Long
  Public ReadOnly Property PathOut As String
  Public ReadOnly Property FileContextOut As IntPtr
  Public ReadOnly Property OffsetOut As Long
  Public ReadOnly Property Size As Long
  Public ReadOnly Property Flags As Integer
  Public Property Result As Integer
End Class

Remarks

Windows:

This event currently is not used.

Linux:

This event fires when the OS needs to copy a range of data from one file to another. The source file is identified either by PathIn or FileContextIn. The destination file is identified either by PathOut or FileContextOut.

OffsetIn specifies the starting offset in the source file from which the data are taken.

OffsetOut specifies the starting offset in the destination file, to which the data should be written.

Size specifies the size of the data block to be copied.

Flags is provided for future extensions and currently is not used.

Create Event (FUSE Component)

This event fires when the OS wants to create a file.

Syntax

C#
VB.NET

public event OnCreateHandler OnCreate;

public delegate void OnCreateHandler(object sender, FUSECreateEventArgs e);

public class FUSECreateEventArgs : EventArgs {
  public string Path { get; }
  public int Mode { get; }
  public IntPtr FileContext { get; set; }
  public int Result { get; set; }
}

Public Event OnCreate As OnCreateHandler

Public Delegate Sub OnCreateHandler(sender As Object, e As FUSECreateEventArgs)

Public Class FUSECreateEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property Mode As Integer
  Public Property FileContext As IntPtr
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS wants to create a file named Path.

Linux:

The application must create the file according to the creation mode and open it afterward. The creation mode is specified in the Mode parameter, whose values correspond to the ones used in the creat() function in POSIX and the Linux API.

The application may use the FileContext parameter to store a file handle or other information that is related to the open file. Windows:

The stored information will be shared between all concurrent file open operations performed on this file.

Destroy Event (FUSE Component)

This event fires upon filesystem exit.

Syntax

C#
VB.NET

public event OnDestroyHandler OnDestroy;

public delegate void OnDestroyHandler(object sender, FUSEDestroyEventArgs e);

public class FUSEDestroyEventArgs : EventArgs {
}

Public Event OnDestroy As OnDestroyHandler

Public Delegate Sub OnDestroyHandler(sender As Object, e As FUSEDestroyEventArgs)

Public Class FUSEDestroyEventArgs Inherits EventArgs
End Class

Remarks

This event fires when the filesystem is shut down.

Error Event (FUSE Component)

This event fires if an unhandled error occurs during an event.

Syntax

C#
VB.NET

public event OnErrorHandler OnError;

public delegate void OnErrorHandler(object sender, FUSEErrorEventArgs e);

public class FUSEErrorEventArgs : EventArgs {
  public int ErrorCode { get; }
  public string Description { get; }
}

Public Event OnError As OnErrorHandler

Public Delegate Sub OnErrorHandler(sender As Object, e As FUSEErrorEventArgs)

Public Class FUSEErrorEventArgs Inherits EventArgs
  Public ReadOnly Property ErrorCode As Integer
  Public ReadOnly Property Description As String
End Class

Remarks

This event fires if an unhandled error occurs during another event. Developers can use this information to track down unhandled errors in an application's event handlers.

IMPORTANT: Not everything is possible or allowed in the event handlers. Please see the Event Handling topic for details.

FAllocate Event (FUSE Component)

This event fires when the OS needs to allocate space for an open file.

Syntax

C#
VB.NET

public event OnFAllocateHandler OnFAllocate;

public delegate void OnFAllocateHandler(object sender, FUSEFAllocateEventArgs e);

public class FUSEFAllocateEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int Mode { get; }
  public long Offset { get; }
  public long Length { get; }
  public int Result { get; set; }
}

Public Event OnFAllocate As OnFAllocateHandler

Public Delegate Sub OnFAllocateHandler(sender As Object, e As FUSEFAllocateEventArgs)

Public Class FUSEFAllocateEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property Mode As Integer
  Public ReadOnly Property Offset As Long
  Public ReadOnly Property Length As Long
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to allocate space for an open file. The file is identified by FileContext, and the Path parameter contains the name of the file.

The event should increase the allocation size (it may not decrease the allocation size) according to the following rule: new allocation size of the file must be the greater of Offset+Length and the current file size. The actual file size must be adjusted up to match the new allocation size unless the Mode parameter includes the value 1 (FALLOC_FL_KEEP_SIZE). In the latter case, the size remains unchanged. On Windows, the component always specifies FALLOC_FL_KEEP_SIZE, but on other systems, the flag may be absent. If the size was increased, the event handler must fill the newly added space with zeros (i.e., zeroize space).

Linux: The OS may send additional flags in the Mode parameter to manipulate file contents. An event handler should check the presense of such flags and deny the request if the requested flags are not supported.

The range of the file data to allocate space for and zeroize starts from Offset and occupies Length bytes.

The event handler must ensure that the required space is allocated for specified file. If the event handler returns success, then any subsequent write request to the specified range must be guaranteed not to fail because of lack of space in the backend storage.

Flush Event (FUSE Component)

This event fires when the OS needs to flush an open file's data out to storage before the file is closed.

Syntax

C#
VB.NET

public event OnFlushHandler OnFlush;

public delegate void OnFlushHandler(object sender, FUSEFlushEventArgs e);

public class FUSEFlushEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int Result { get; set; }
}

Public Event OnFlush As OnFlushHandler

Public Delegate Sub OnFlushHandler(sender As Object, e As FUSEFlushEventArgs)

Public Class FUSEFlushEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public Property Result As Integer
End Class

Remarks

This event fires any time the OS needs the virtual filesystem to flush data out to storage when the file is about to be closed. The file to flush is identified by either Path or FileContext.

When the file is opened several times, the event will be fired for each file close. Linux:

The OS gives no guarantee as to the number of times (if any) the event will fire.

To handle this event properly, applications must flush the requested data, writing it out to their backend storage.

FSync Event (FUSE Component)

This event fires when the OS needs to flush an open file's data out to storage.

Syntax

C#
VB.NET

public event OnFSyncHandler OnFSync;

public delegate void OnFSyncHandler(object sender, FUSEFSyncEventArgs e);

public class FUSEFSyncEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int DataSync { get; }
  public int Result { get; set; }
}

Public Event OnFSync As OnFSyncHandler

Public Delegate Sub OnFSyncHandler(sender As Object, e As FUSEFSyncEventArgs)

Public Class FUSEFSyncEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property DataSync As Integer
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs the virtual filesystem to flush data of the file out to storage, which can happen at any time the file is opened. The file to flush is identified by either Path or FileContext.

To handle this event properly, applications must flush the requested data, writing it out to their backend storage.

Linux:

The nonzero of the DataSync parameter indicates that only the user data should be flushed and not the metadata.

GetAttr Event (FUSE Component)

This event fires when the OS needs information about a file or directory.

Syntax

C#
VB.NET

public event OnGetAttrHandler OnGetAttr;

public delegate void OnGetAttrHandler(object sender, FUSEGetAttrEventArgs e);

public class FUSEGetAttrEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public long Ino { get; set; }
  public int Mode { get; set; }
  public int Uid { get; set; }
  public int Gid { get; set; }
  public int LinkCount { get; set; }
  public long Size { get; set; }
  public DateTime ATime { get; set; }
  public DateTime MTime { get; set; }
  public DateTime CTime { get; set; }
  public int Result { get; set; }
}

Public Event OnGetAttr As OnGetAttrHandler

Public Delegate Sub OnGetAttrHandler(sender As Object, e As FUSEGetAttrEventArgs)

Public Class FUSEGetAttrEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public Property Ino As Long
  Public Property Mode As Integer
  Public Property Uid As Integer
  Public Property Gid As Integer
  Public Property LinkCount As Integer
  Public Property Size As Long
  Public Property ATime As DateTime
  Public Property MTime As DateTime
  Public Property CTime As DateTime
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs information about the file or directory identified by either Path or FileContext (the latter in most cases will not be initialized). If the entry with the specified name does not exist, the handler must return ENOENT in the Result parameter.

The Ino parameter should be set to the Id of the file, which must be unique within a filesystem. Ino is optional on Windows and is ignored on Linux, where FUSE internally generates internal Ids.

The Mode parameter is a combination of bit flags.

Linux: Mode may include any appropriate file mode flags. See inode(7) for more information.

Windows: The Uid, Gid, and LinkCount parameters are not used.

Linux: The Uid and Gid parameters must be set to the owner's user Id and group Id, respectively. LinkCount should be set to the number of hard links that the file has (which usually is 1).

Size must be set to the size of the file's data. For directories, the parameter should be set to 0.

ATime, MTime, CTime: Set, respectively, to the Access Time, Modification Time, and Creation Time values of the file or directory. All date/time parameters in the component are specified in UTC.

To convert Unix time to the format that is suitable for this event, use the UnixTimeToFileTime method.

Windows:

Any nonapplicable time values can be left unchanged, or set to January 1, 1601 00:00:00 UTC.

Note: For this event, returning ERROR_FILE_INVALID has no effect.

Init Event (FUSE Component)

This event fires on filesystem startup.

Syntax

C#
VB.NET

public event OnInitHandler OnInit;

public delegate void OnInitHandler(object sender, FUSEInitEventArgs e);

public class FUSEInitEventArgs : EventArgs {
  public int Result { get; set; }
}

Public Event OnInit As OnInitHandler

Public Delegate Sub OnInitHandler(sender As Object, e As FUSEInitEventArgs)

Public Class FUSEInitEventArgs Inherits EventArgs
  Public Property Result As Integer
End Class

Remarks

This event fires when the filesystem is started.

Lock Event (FUSE Component)

This event fires when the OS needs to lock or unlock the range of bytes of a file.

Syntax

C#
VB.NET

public event OnLockHandler OnLock;

public delegate void OnLockHandler(object sender, FUSELockEventArgs e);

public class FUSELockEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int LockType { get; }
  public long LockStart { get; }
  public long LockLen { get; }
  public int Cmd { get; }
  public long LockOwner { get; }
  public int LockPid { get; set; }
  public int Result { get; set; }
}

Public Event OnLock As OnLockHandler

Public Delegate Sub OnLockHandler(sender As Object, e As FUSELockEventArgs)

Public Class FUSELockEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property LockType As Integer
  Public ReadOnly Property LockStart As Long
  Public ReadOnly Property LockLen As Long
  Public ReadOnly Property Cmd As Integer
  Public ReadOnly Property LockOwner As Long
  Public Property LockPid As Integer
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to lock or unlock the range of bytes of the file, identified by either Path or FileContext. Local locking is performed by the system and your application needs to handle this even when it needs to perform an operation over the network.

LockType identifies whether the range is to be locked or unlocked. It can be one of the following:


FUSE_RDLCK	`0x0000`	Read lock should be acquired. Other applications may read from the locked range but not write to it. The constant is the same as the F_RDLCK constant used in Linux.
FUSE_WRLCK	`0x0001`	Write lock should be acquired. No other application may write to the locked range. The constant is the same as the F_WRLCK constant used in Linux.
FUSE_UNLCK	`0x0002`	The lock should be released. The constant is the same as the F_UNLCK constant used in Linux.

LockStart and LockLen specify the starting position and the length of the block to be locked or unlocked. Cmd can be one of


FUSE_GETLK	`0x0005`	The lock owner is to be retrieved. This command is not used in Windows. In Linux, the process identifier (PID) of the lock owner must be returned. The constant is the same as the F_GETLK constant used in Linux.
FUSE_SETLK	`0x0006`	Set lock. If the lock cannot be set immediately, return immediately with an error (EAGAIN and EACCES are recommended). The constant is the same as the F_SETLK constant used in Linux.
FUSE_SETLKW	`0x0007`	Set lock and wait. If the lock cannot be set immediately, wait until this becomes possible. The constant is the same as the F_SETLKW constant used in Linux.

Windows:

LockOwner and LockPid parameters are not used and are set to 0.

Linux:

This event fires for a POSIX-style lock. For additional information about LockOwner and other parameters, please refer to http://libfuse.github.io/doxygen/structfuse__operations.html#a1c3fff5cf0c1c2003d117e764b9a76fd.

if Cmd is F_GETLK, the event handler should place the PID of the owner process to the LockPid parameter.

MkDir Event (FUSE Component)

This event fires when the OS needs to create a directory.

Syntax

C#
VB.NET

public event OnMkDirHandler OnMkDir;

public delegate void OnMkDirHandler(object sender, FUSEMkDirEventArgs e);

public class FUSEMkDirEventArgs : EventArgs {
  public string Path { get; }
  public int Mode { get; }
  public int Result { get; set; }
}

Public Event OnMkDir As OnMkDirHandler

Public Delegate Sub OnMkDirHandler(sender As Object, e As FUSEMkDirEventArgs)

Public Class FUSEMkDirEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property Mode As Integer
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to create a directory, referenced as Path.

The Mode parameter is a combination of bit flags.

Windows:

Mode includes 0x4000 (S_IFDIR) to indicate that the entry is a directory and may include 0x80 (S_IWUSR) to indicate that the directory must not have its ReadOnly attribute set. If the 0x80 flag is not set, the event handler must set a read-only attribute for a newly created directory.

Linux:

Mode includes permission bits and may include additional bits depending on the OS.

Open Event (FUSE Component)

This event fires when the OS wants to open a file.

Syntax

C#
VB.NET

public event OnOpenHandler OnOpen;

public delegate void OnOpenHandler(object sender, FUSEOpenEventArgs e);

public class FUSEOpenEventArgs : EventArgs {
  public string Path { get; }
  public int Flags { get; }
  public bool DirectIO { get; set; }
  public bool KeepCache { get; set; }
  public bool NonSeekable { get; set; }
  public IntPtr FileContext { get; set; }
  public int Result { get; set; }
}

Public Event OnOpen As OnOpenHandler

Public Delegate Sub OnOpenHandler(sender As Object, e As FUSEOpenEventArgs)

Public Class FUSEOpenEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property Flags As Integer
  Public Property DirectIO As Boolean
  Public Property KeepCache As Boolean
  Public Property NonSeekable As Boolean
  Public Property FileContext As IntPtr
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS wants to open the existing file specified by Path using the open options reflected in Flags. The set of possible flags and options corresponds to the Flags parameter of Linux open(2) call.

The application may use the FileContext parameter to store a file handle or other information, related to the open file.

Windows:

The stored information will be shared between all concurrent file open operations performed on this file.

Linux:

DirectIO parameter may be set by the application to tell the kernel that buffering or caching should be avoided. KeepCache parameter may be set by the application to tell the kernel that existing file caches (if any) should not be invalidated. NonSeekable parameter may be set by the application to tell the kernel that the file is not seekable.

Read Event (FUSE Component)

This event fires when the OS needs to read data from an open file.

Syntax

C#
VB.NET

public event OnReadHandler OnRead;

public delegate void OnReadHandler(object sender, FUSEReadEventArgs e);

public class FUSEReadEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public IntPtr Buffer { get; }
  public long Size { get; }
  public long Offset { get; }
  public int Result { get; set; }
}

Public Event OnRead As OnReadHandler

Public Delegate Sub OnReadHandler(sender As Object, e As FUSEReadEventArgs)

Public Class FUSEReadEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property Buffer As IntPtr
  Public ReadOnly Property Size As Long
  Public ReadOnly Property Offset As Long
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to read data from an already-open file, identified by either Path or FileContext.

To handle this event properly, applications should read Size bytes of data from the specified file into the memory region pointed to by Buffer. Reading must begin at the specified Offset in the file and all of the requested data are expected to be read. Applications must not attempt to copy more than Size bytes of data into Buffer.

Please see the Buffer Parameters topic for more information on how to work with memory buffer event parameters.

When reading is complete, applications must set Result to the actual number of bytes written to Buffer. Note: Although it is technically possible for an application to return fewer than Size bytes of data, doing so is abnormal and should be avoided. Most processes treat read requests as "all or nothing", so returning less data than requested is likely to cause an ungraceful failure.

ReadDir Event (FUSE Component)

This event fires when the OS wants to read (enumerate) a directory's contents.

Syntax

C#
VB.NET

public event OnReadDirHandler OnReadDir;

public delegate void OnReadDirHandler(object sender, FUSEReadDirEventArgs e);

public class FUSEReadDirEventArgs : EventArgs {
  public string Path { get; }
  public long FillerContext { get; }
  public int Result { get; set; }
}

Public Event OnReadDir As OnReadDirHandler

Public Delegate Sub OnReadDirHandler(sender As Object, e As FUSEReadDirEventArgs)

Public Class FUSEReadDirEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FillerContext As Long
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS wants to enumerate the contents of the directory, identified by Path. In response to this event, the application must call the FillDir method and pass the FillerContextparameter as well as the information about the directory entry. Please refer to the description of FillDir for further details.

If FillDir returns an error code, set Result to the returned code (do not negate the code). If there are no more files to pass, set Result to 0.

Note: For this event, returning ERROR_FILE_INVALID has no effect.

Release Event (FUSE Component)

This event fires when the OS needs to release (close) a file.

Syntax

C#
VB.NET

public event OnReleaseHandler OnRelease;

public delegate void OnReleaseHandler(object sender, FUSEReleaseEventArgs e);

public class FUSEReleaseEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public int Flags { get; }
  public int Result { get; set; }
}

Public Event OnRelease As OnReleaseHandler

Public Delegate Sub OnReleaseHandler(sender As Object, e As FUSEReleaseEventArgs)

Public Class FUSEReleaseEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property Flags As Integer
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS wants to close the file identified by either Path or FileContext.

The Flags parameter contains the same value as the one passed during file creation or opening.

Windows:

If the file is opened two or more times concurrently (i.e., several open handles exist), this parameter will contain the flags of the last open operation rather than the flags of an operation that opened a handle being closed.

Rename Event (FUSE Component)

This event fires when the OS wants to rename or move a file or directory within the virtual filesystem.

Syntax

C#
VB.NET

public event OnRenameHandler OnRename;

public delegate void OnRenameHandler(object sender, FUSERenameEventArgs e);

public class FUSERenameEventArgs : EventArgs {
  public string OldPath { get; }
  public string NewPath { get; }
  public int Flags { get; }
  public int Result { get; set; }
}

Public Event OnRename As OnRenameHandler

Public Delegate Sub OnRenameHandler(sender As Object, e As FUSERenameEventArgs)

Public Class FUSERenameEventArgs Inherits EventArgs
  Public ReadOnly Property OldPath As String
  Public ReadOnly Property NewPath As String
  Public ReadOnly Property Flags As Integer
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS wants to rename or move the specified file or directory from OldPath to NewPath, both of which are fully qualified and located in the virtual filesystem. The Flags parameter currently is not used.

To handle this event properly, applications must perform any actions needed to rename or move the specified file or directory in their backend storage, overwriting the destination file if necessary. An application may also, for its own reasons, decide not to overwrite a destination file, in which case it must deny the operation by returning an appropriate error code via ResultCode.

Windows:

This event fires only if a file or directory with the specified NewPath does not exist; or if such a file does exist, and an overwrite was requested. Cases in which a file with the specified NewPath exists, and an overwrite was not requested, are handled by the component internally. Note: Windows only allows files to be overwritten, and denies a rename or move request automatically if the destination is an existing directory.

Any handles to the file being renamed are closed before the rename operation and are reopened after the operation. If the rename operation fails, then the file handles are reopened using the old name. If any of the reopen operations fail, the reopening process is stopped, and any handles that already have been reopened are closed again.

The value returned by the application in the ResultCode parameter is passed back to the system.

RmDir Event (FUSE Component)

This event fires when the OS wants to remove (delete) a directory.

Syntax

C#
VB.NET

public event OnRmDirHandler OnRmDir;

public delegate void OnRmDirHandler(object sender, FUSERmDirEventArgs e);

public class FUSERmDirEventArgs : EventArgs {
  public string Path { get; }
  public int Result { get; set; }
}

Public Event OnRmDir As OnRmDirHandler

Public Delegate Sub OnRmDirHandler(sender As Object, e As FUSERmDirEventArgs)

Public Class FUSERmDirEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS has decided to delete the directory specified by Path.

Windows:

The resulting error value is ignored because of the OS design.

StatFS Event (FUSE Component)

This event fires when the OS needs information about the virtual drive's capacity and free space.

Syntax

C#
VB.NET

public event OnStatFSHandler OnStatFS;

public delegate void OnStatFSHandler(object sender, FUSEStatFSEventArgs e);

public class FUSEStatFSEventArgs : EventArgs {
  public string Path { get; }
  public long BlockSize { get; set; }
  public long TotalBlocks { get; set; }
  public long FreeBlocks { get; set; }
  public long FreeBlocksAvail { get; set; }
  public long TotalFiles { get; set; }
  public long FreeFiles { get; set; }
  public int MaxFilenameLength { get; set; }
  public int Result { get; set; }
}

Public Event OnStatFS As OnStatFSHandler

Public Delegate Sub OnStatFSHandler(sender As Object, e As FUSEStatFSEventArgs)

Public Class FUSEStatFSEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public Property BlockSize As Long
  Public Property TotalBlocks As Long
  Public Property FreeBlocks As Long
  Public Property FreeBlocksAvail As Long
  Public Property TotalFiles As Long
  Public Property FreeFiles As Long
  Public Property MaxFilenameLength As Integer
  Public Property Result As Integer
End Class

Remarks

This event fires anytime the OS needs to retrieve the virtual drive's total storage capacity and free space. This event is mandatory to handle. Without it, the OS will not be able to initialize the drive.

To handle this event properly, applications must set event parameters accordingly. BlockSize must be set to the size of the block, and TotalBlocks must be set to the total number of blocks on the virtual drive. FreeBlocks and FreeBlocksAvail denote the number of free blocks available to the system and to the unprivileged user, respectively.

Windows:

The minimum drive size accepted by Windows is 6144 bytes. However, the component adjusts the minimum size to be at least 49152 bytes to ensure compatibility with possible changes in future Windows updates.

Linux:

TotalFiles and FreeFiles must be set to the total and available number of file slots (inodes) available within a filesystem. MaxFilenameLength should be set to the maximal length of the filename (path component) supported by the filesystem.

Truncate Event (FUSE Component)

This event fires when the OS needs to truncate (set the size of) a file.

Syntax

C#
VB.NET

public event OnTruncateHandler OnTruncate;

public delegate void OnTruncateHandler(object sender, FUSETruncateEventArgs e);

public class FUSETruncateEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public long Size { get; }
  public int Result { get; set; }
}

Public Event OnTruncate As OnTruncateHandler

Public Delegate Sub OnTruncateHandler(sender As Object, e As FUSETruncateEventArgs)

Public Class FUSETruncateEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property Size As Long
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS wants to set the size of the file, which is identified by either Path or FileContext.

Note: On non-Windows systems, FileContext may be 0 even for a file that is opened at the moment when the event fires.

The Size parameter contains the new file size. If the new size is larger than the old size, the added space is expected to be filled with null bytes ('\0').

Unlink Event (FUSE Component)

This event fires when the OS wants to unlink (delete) a file.

Syntax

C#
VB.NET

public event OnUnlinkHandler OnUnlink;

public delegate void OnUnlinkHandler(object sender, FUSEUnlinkEventArgs e);

public class FUSEUnlinkEventArgs : EventArgs {
  public string Path { get; }
  public int Result { get; set; }
}

Public Event OnUnlink As OnUnlinkHandler

Public Delegate Sub OnUnlinkHandler(sender As Object, e As FUSEUnlinkEventArgs)

Public Class FUSEUnlinkEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS has decided to delete the file specified by Path.

Windows:

The resulting error value is ignored because of the OS design.

UTime Event (FUSE Component)

This event fires when the OS needs to change access and modification times of a file.

Syntax

C#
VB.NET

public event OnUTimeHandler OnUTime;

public delegate void OnUTimeHandler(object sender, FUSEUTimeEventArgs e);

public class FUSEUTimeEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public DateTime ATime { get; }
  public DateTime MTime { get; }
  public int Result { get; set; }
}

Public Event OnUTime As OnUTimeHandler

Public Delegate Sub OnUTimeHandler(sender As Object, e As FUSEUTimeEventArgs)

Public Class FUSEUTimeEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property ATime As DateTime
  Public ReadOnly Property MTime As DateTime
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to change access and modification times of the file, which is identified by either Path or FileContext. The ATime and MTime parameters contain the access time and modification time, respectively. All date/time parameters in the component are specified in UTC

To convert the values of the ATime and MTime parameters to Unix time, use the FileTimeToUnixTime method.

Write Event (FUSE Component)

This event fires when the OS needs to write data to an open file.

Syntax

C#
VB.NET

public event OnWriteHandler OnWrite;

public delegate void OnWriteHandler(object sender, FUSEWriteEventArgs e);

public class FUSEWriteEventArgs : EventArgs {
  public string Path { get; }
  public IntPtr FileContext { get; }
  public bool WritePage { get; }
  public long Offset { get; }
  public IntPtr Buffer { get; }
  public long Size { get; }
  public int Result { get; set; }
}

Public Event OnWrite As OnWriteHandler

Public Delegate Sub OnWriteHandler(sender As Object, e As FUSEWriteEventArgs)

Public Class FUSEWriteEventArgs Inherits EventArgs
  Public ReadOnly Property Path As String
  Public ReadOnly Property FileContext As IntPtr
  Public ReadOnly Property WritePage As Boolean
  Public ReadOnly Property Offset As Long
  Public ReadOnly Property Buffer As IntPtr
  Public ReadOnly Property Size As Long
  Public Property Result As Integer
End Class

Remarks

This event fires when the OS needs to write data to the already-open file, which is identified by either Path or FileContext.

To handle this event properly, applications should write Size bytes of data from the memory region pointed to by Buffer to the specified file. Writing must begin at the specified Offset in the file and all of the provided data are expected to be written.

Please see the Buffer Parameters topic for more information on how to work with memory buffer event parameters.

The WritePage parameter will be set to a nonzero value when writing is performed by the cache manager or another system component. If this is the case, FileContext may not match the value that would be passed in the case of a nonbuffered write by a user-mode process.

When writing is complete, applications must set Result to the actual number of bytes written to the file.

ProcessAccessRule Type

Represents an access rule granting or denying some process a specific access right.

Remarks

This type represents an access rule that grants or denies some process a specific access right.

The following fields are available:

Fields

DesiredAccess
int (read-only)
Default: 0

The kind of access granted or denied.

This field specifies what kind of access is granted or denied by the rule. Possible values are:


STG_DACCESS_READ	`0x00000001`	Grant/deny read access.
STG_DACCESS_WRITE	`0x00000002`	Grant/deny write access.
STG_DACCESS_READWRITE	`0x00000003`	Grant/deny read and write access.

IncludeChildren
bool (read-only)
Default: False

Whether child processes are affected.

This field indicates whether the rule applies to children of the target process.

ProcessId
int (read-only)
Default: 0

The Id of the target process.

This field reflects the target process's Id (PID). Will be 0 if the target process was specified by ProcessName, or -1 if the rule applies to all processes.

ProcessName
string (read-only)
Default: ""

The filename of the target process's executable.

This field reflects the full file name of the target process's executable. Will be empty if the target process was specified by ProcessId (or if the rule applies to all processes, in which case ProcessId will be -1).

Config Settings (FUSE Component)

The component accepts one or more of the following configuration settings. Configuration settings are similar in functionality to properties, but they are rarely used. In order to avoid "polluting" the property namespace of the component, access to these internal properties is provided through the Config method.

FUSE Config Settings

AsyncMountingPointNotifications: Whether system broadcasts for virtual drive mounting and unmounting are sent asynchronously.

This Windows-only configuration setting specifies whether the WM_DEVICECHANGE broadcast is sent asynchronously (true) or synchronously (false) when the virtual drive is mounted or unmounted using the Mount and Unmount methods, respectively.

By default, this setting is enabled, and the broadcast is sent asynchronously. Typically, this is sufficient, but applications may disable this setting during unmounting if they find that Windows File Explorer is still presenting virtual drives as available after they have been deleted (which may occur if the application exits immediately after unmounting a virtual drive).

On Linux, this setting is not used.

ForceFileClose: Whether the driver should force files to close after the last handle to them is closed (Windows only).

This Windows-only configuration setting specifies the desired behavior in handling of files when they are closed.

A file is not closed after the last handle to it is closed (i.e., after the last CleanupFile event fires); it is closed only after the last CloseFile event fires. If a file is cached or memory-mapped, the system may hold it open for quite a while (minutes, or even hours) after the last handle to it is closed.

When this configuration setting is enabled (default), then after the last handle to a file is closed, the driver will wait some time (as defined by the ForceFileCloseDelay setting), and then it will attempt to flush and purge any in-memory file data, allowing it to be formally closed.

Disabling this configuration setting slightly improves performance in the case of repeated access to files on the virtual drive; however, CloseFile events can be significantly delayed.

Note: This setting cannot be changed after a virtual drive is created, and it cannot be changed within events.

On Linux, this setting is not used.

ForceFileCloseDelay: Specifies the timeout between the closing of a last handle of a file and the moment the driver tries to close the file.

This configuration setting is a companion to the ForceFileClose setting. The timeout is set in milliseconds: the default value is 3,000 ms, and the minimal allowed value is 500 ms.

Note: This setting cannot be changed after a virtual drive is created, and it cannot be changed within events.

LinuxFUSEParams: A placeholder for additional parameters used for fine-tuning FUSE on Linux.

The string that the application passes is parsed, and for each argument, the fuse_opt_add_arg() function of FUSE is called. Arguments must start with "-" (dash); multiple arguments must be separated with a space.

Example: "-oallow_other -omax_read=4096" (without quotes).

MaxWorkerThreadCount: The maximum number of worker threads to use to fire events.

(CBFS and FUSE components on Windows only) This setting specifies the maximum number of worker threads the component may create to fire events on when the SerializeEvents property is set to seOnMultipleThreads. (If other cases, this setting does not apply.)

By default, this setting is set to 0, and the driver automatically chooses an optimal number of threads using this equation: 4 * number_of_processors.

MetadataCacheEnabled: Whether or not the metadata cache should be used.

This Windows-only configuration setting specifies whether the file metadata cache is enabled for a virtual drive.

By default, this setting is enabled, and the component caches file information and uses the cached metadata to serve operating system requests, thus reducing how often the GetAttr events fire.

While a file or directory is open, its metadata is kept available in a special record called a File Control Block, regardless of whether or not the metadata cache is enabled.

Disable this setting if your filesystem contents may be modified on the backend side, and the modifications need to be re-read when the OS refreshes its knowledge about directory contents.

On Linux, this setting is not used.

MinWorkerThreadCount: The minimum number of worker threads to use to fire events.

(CBFS and FUSE components on Windows only) This setting specifies the minimum number of worker threads the component should create to fire events on when the SerializeEvents property is set to seOnMultipleThreads. (In other cases, this setting does not apply.)

By default, this setting is set to 0, and the driver automatically chooses an optimal number of threads using this equation: max(number_of_processors, 4). If this setting's value exceeds the MaxWorkerThreadCount value, the latter is used instead.

NonExistentFilesCacheEnabled: Whether or not the nonexistent files cache should be used.

This Windows-only configuration setting specifies whether the nonexistent files cache is enabled for a virtual drive.

By default, this setting is enabled, and the component will cache any GetAttr responses that indicate that the requested file does not exist. If another request is later made for the same file, the component will use this information to automatically report a file not found error rather than firing the GetAttr event again.

Disable this setting if your filesystem contents may be modified on the backend side, and the modifications need to be re-read when the OS refreshes its knowledge about directory contents.

On Linux, this setting is not used.

Timeout: Specifies how many milliseconds the driver will wait for events to execute before cancelling the underlying OS requests. (Windows-only).

Because the FUSE component's events typically are tied directly to requests from the OS itself, it is critical that event handlers complete quickly to prevent the system from being blocked. To prevent such blocking, the CBFS Connect system driver can enforce request timeouts on a per-virtual-drive basis.

When timeout enforcement is in effect, and an event executes long enough for its timeout to expire, the driver cancels the underlying request by reporting an error to the OS. The tardy event still runs to completion, but any results it returns once finished are ignored because the underlying request has already been handled.

Applications should always strive to ensure that all event handlers complete quickly, even if request timeouts are disabled. Do not perform time-consuming work, especially network operations, within event handlers; offload such work to background threads.

Valid values are 0, which disables event timeouts, and values greater than or equal to 3000. (Passing a nonzero value less than 3000 will cause the Config method to fail with an ERROR_IMPLEMENTATION_LIMIT (1292, 0x50C) error code.) The default value is 30,000 or 30 seconds.

TranslateDOSCharsInEnumMasks: Whether the DOS wildcard characters should be translated during search.

In addition to * and ?, Windows uses special wildcard characters for compatibility with DOS applications and short (8.3) names. These characters are <, >, and " . Their meanings are described in MSDN and .NET reference source code as follows:

DOS_STAR (<) - Matches zero or more characters until encountering and matching the final dot (.) in the name. (Source code comment: "DOS_STAR matches any character except . zero or more times.")
DOS_QM (>) - Matches any single character or, upon encountering a period or end of name string, advances the expression to the end of the set of contiguous DOS_QMs. (Source code comment: "A DOS_DOT can match either a period, or zero characters beyond the end of name.")
DOS_DOT (") - Matches either a period or zero characters beyond the name string. (Source code comment: "DOS_QM is the most complicated. If the name is finished, we can match zero characters. If this name is a '.', we don't match, but look at the next expression. Otherwise, we match a single character.")

When this setting is enabled (default), the component translates them to * and ?, but such a translation is not able to fully represent all the logic behind DOS_* wildcard characters; however, this translation is usually sufficient for end-user needs.

If your application needs to perform exact matching, disable this setting and implement handling of DOS_* wildcard characters in your application. Further explanation about the characters can be found in the MSDN article. The RtlIsNameInExpression function of Windows API may be used to perform such a matching. Note: as the explanation states, "When you do a case-insensitive search and don't provide a translation table, the name is converted to uppercase."

In FUSE on Linux, this setting is not used.

WindowsVolumeLabel: A human-readable label for the volume in Windows.

This Windows-only configuration setting makes it possible for an application to specify the text label, displayed for the volume by Explorer and some other applications.

The length of the label must not exceed 32 characters, which is the maximum length supported by the OS.

On Linux, this setting is not used.

WorkerInitialStackSize: The initial stack size to create worker threads with.

(CBFS and FUSE components on Windows only) This setting specifies the initial size of the stack each worker thread is created with. The system rounds this value to the nearest page.

By default, this setting is set to 0, and the driver uses a default stack size (currently, 1 MB).

Note: This setting cannot be changed when Active is true, and it cannot be changed within events.

Base Config Settings

BuildInfo: Information about the product's build.

When queried, this setting will return a string containing information about the product's build.

LicenseInfo: Information about the current license.

When queried, this setting will return a string containing information about the license this instance of a component is using. It will return the following information:

Product: The product the license is for.
Product Key: The key the license was generated from.
License Source: Where the license was found (e.g., RuntimeLicense, License File).
License Type: The type of license installed (e.g., Royalty Free, Single Server).

Trappable Errors (FUSE Component)

The component uses Unix/Linux system error codes during operation, as necessary. Please refer to the Error Handling topic for more information.