UWF_Volume (Industry 8.1)
7/8/2014
Review the syntax, members, and examples of the UWF_Volume WMI provider class for Windows Embedded 8.1 Industry (Industry 8.1).
This class manages a volume protected by Unified Write Filter (UWF).
Syntax
class UWF_Volume {
[key, Read] boolean CurrentSession;
[key, Read] string DriveLetter;
[key, Read] string VolumeName;
[Read, Write] boolean BindByDriveLetter;
[Read] boolean CommitPending;
[Read, Write] boolean Protected;
UInt32 CommitFile([in] string FileFullPath);
UInt32 CommitFileDeletion(string FileName);
UInt32 Protect();
UInt32 Unprotect();
UInt32 SetBindByDriveLetter(boolean bBindByVolumeName);
UInt32 AddExclusion(string FileName);
UInt32 RemoveExclusion(string FileName);
UInt32 RemoveAllExclusions();
UInt32 FindExclusion([in] string FileName, [out] bFound);
UInt32 GetExclusions([out, EmbeddedInstance("UWF_ExcludedFile")] string ExcludedFiles[]);
};
Members
The following tables list the methods and properties that belong to this class.
Methods
Method |
Description |
|---|---|
Adds a file or folder to the file exclusion list for a volume protected byUWF. |
|
Commits changes from the overlay to the physical volume for a specified file on a volume protected by Unified Write Filter (UWF). |
|
Deletes a protected file from the volume, and commits the deletion to the physical volume. |
|
Determines whether a specific file or folder is in the exclusion list for a volume protected byUWF. |
|
Retrieves a list of all file exclusions for a volume protected byUWF. |
|
Protects the volume after the next system restart, if UWF is enabled after the restart. |
|
Removes all files and folders from the file exclusion list for a volume protected byUWF. |
|
Removes a specific file or folder from the file exclusion list for a volume protected byUWF. |
|
Sets the BindByDriveLetter property, which indicates whether the UWF volume is bound to the physical volume by drive letter or by volume name. |
|
Disables UWF protection of the volume after the next system restart. |
Properties
Property |
Data type |
Qualifiers |
Description |
|---|---|---|---|
BindByDriveLetter |
Boolean |
[read, write] |
Indicates the type of binding that the volume uses. Set to True to bind the volume by DriveLetter(loose binding); set to False to bind the volume by VolumeName (tight binding). |
CommitPending |
Boolean |
[read] |
Reserved for Microsoft use. |
CurrentSession |
Boolean |
[key, read] |
Indicates which session the object contains settings for. True if settings are for the current session; False if settings are for the next session that follows a restart. |
DriveLetter |
string |
[key, read] |
The drive letter of the volume. If the volume does not have a drive letter, this value is NULL. |
Protected |
Boolean |
[read, write] |
If CurrentSession is true, indicates whether the volume is currently protected by UWF. If CurrentSession is false, indicates whether the volume is protected in the next session after the device restarts. |
VolumeName |
string |
[key, read] |
The unique identifier of the volume on the current system. The VolumeName is the same as the DeviceID property of the Win32_Volume class for the volume. |
Remarks
You must use an administrator account to change any properties or call any methods that change the configuration settings.
Example
The following example demonstrates how to protect or unprotect a volume with UWF by using the Windows Management Instrumentation (WMI) provider in a Windows PowerShell script.
The Windows PowerShell script creates a function, Set-ProtectVolume, that turns UWF protection on or off for a volume. The script then demonstrates how to use the function.
$COMPUTER = "localhost"
$NAMESPACE = "root\standardcimv2\embedded"
# Define common parameters
$CommonParams = @{"namespace"=$NAMESPACE; "computer"=$COMPUTER}
# Create a function to protect or unprotect a volume based on the drive letter of the volume
function Set-ProtectVolume($driveLetter, [bool] $enabled) {
# Each volume has two entries in UWF_Volume, one for the current session and one for the next session after a restart
# You can only change the protection status of a drive for the next session
$nextConfig = Get-WMIObject -class UWF_Volume @CommonParams |
where {
$_.DriveLetter -eq "$driveLetter" -and $_.CurrentSession -eq $false
};
# If a volume entry is found for the drive letter, enable or disable protection based on the $enabled parameter
if ($nextConfig) {
Write-Host "Setting drive protection on $driveLetter to $enabled"
if ($Enabled -eq $true) {
$nextConfig.Protect() | Out-Null;
} else {
$nextConfig.Unprotect() | Out-Null;
}
}
# If the drive letter does not match a volume, create a new UWF_volume instance
else {
Write-Host "Error: Could not find $driveLetter. Protection is not enabled."
}
}
# The following sample commands demonstrate how to use the Set-ProtectVolume function
# to protect and unprotect volumes
Set-ProtectVolume "C:" $true
Set-ProtectVolume "D:" $true
Set-ProtectVolume "C:" $false
Example
The following example demonstrates how to manage UWF file and folder exclusions by using the WMI provider in a Windows PowerShell script. The Windows PowerShell script creates four functions, and then demonstrates how to use them.
The first function, Get-FileExclusions, displays a list of UWF file exclusions that exist on a volume. Exclusions for both the current session and the next session that follows a restart are displayed.
The second function, Add-FileExclusion, adds a file or folder to the UWF exclusion list for a given volume. The exclusion is added for the next session that follows a restart.
The third function, Remove-FileExclusion, removes a file or folder from the UWF exclusion list for a given volume. The exclusion is removed for the next session that follows a restart.
The fourth function, Clear-FileExclusions, removes all UWF file and folder exclusions from a given volume. The exclusions are removed for the next session that follows a restart.
$COMPUTER = "localhost"
$NAMESPACE = "root\standardcimv2\embedded"
# Define common parameters
$CommonParams = @{"namespace"=$NAMESPACE; "computer"=$COMPUTER}
function Get-FileExclusions($driveLetter) {
# This function lists the UWF file exclusions for a volume, both
# for the current session as well as the next session after a restart
# $driveLetter is the drive letter of the volume
# Get the UWF_Volume configuration for the current session
$currentConfig = Get-WMIObject -class UWF_Volume @CommonParams |
where {
$_.DriveLetter -eq "$driveLetter" -and $_.CurrentSession -eq $true
};
# Get the UWF_Volume configuration for the next session after a restart
$nextConfig = Get-WMIObject -class UWF_Volume @CommonParams |
where {
$_.DriveLetter -eq "$driveLetter" -and $_.CurrentSession -eq $false
};
# Display file exclusions for the current session
if ($currentConfig) {
Write-Host "The following files and folders are currently excluded from UWF filtering for $driveLetter";
$currentExcludedList = $currentConfig.GetExclusions()
if ($currentExcludedList) {
foreach ($fileExclusion in $currentExcludedList.ExcludedFiles) {
Write-Host " " $fileExclusion.FileName
}
} else {
Write-Host " None"
}
} else {
Write-Error "Could not find drive $driveLetter";
}
# Display file exclusions for the next session after a restart
if ($nextConfig) {
Write-Host ""
Write-Host "The following files and folders will be excluded from UWF filtering for $driveLetter after the next restart:";
$nextExcludedList = $nextConfig.GetExclusions()
if ($nextExcludedList) {
foreach ($fileExclusion in $nextExcludedList.ExcludedFiles) {
Write-Host " " $fileExclusion.FileName
}
} else {
Write-Host " None"
}
Write-Host ""
}
}
function Add-FileExclusion($driveLetter, $exclusion) {
# This function adds a new UWF file exclusion to a volume
# The new file exclusion takes effect the next time the device is restarted and UWF is enabled
# $driveLetter is the drive letter of the volume
# $exclusion is the path and filename of the file or folder exclusion
# Get the configuration for the next session for the volume
$nextConfig = Get-WMIObject -class UWF_Volume @CommonParams |
where {
$_.DriveLetter -eq "$driveLetter" -and $_.CurrentSession -eq $false
};
# Add the exclusion
if ($nextConfig) {
$nextConfig.AddExclusion($exclusion) | Out-Null;
Write-Host "Added exclusion $exclusion for $driveLetter";
} else {
Write-Error "Could not find drive $driveLetter";
}
}
function Remove-FileExclusion($driveLetter, $exclusion) {
# This function removes a UWF file exclusion from a volume
# The file exclusion is removed the next time the device is restarted
# $driveLetter is the drive letter of the volume
# $exclusion is the path and filename of the file or folder exclusion
# Get the configuration for the next session for the volume
$nextConfig = Get-WMIObject -class UWF_Volume @CommonParams |
where {
$_.DriveLetter -eq "$driveLetter" -and $_.CurrentSession -eq $false
};
# Try to remove the exclusion
if ($nextConfig) {
try {
$nextConfig.RemoveExclusion($exclusion) | Out-Null;
Write-Host "Removed exclusion $exclusion for $driveLetter";
} catch {
Write-Host "Could not remove exclusion $exclusion on drive $driveLetter"
}
} else {
Write-Error "Could not find drive $driveLetter";
}
}
function Clear-FileExclusions($driveLetter) {
# This function removes all UWF file exclusions on a volume
# The file exclusions are removed the next time the device is restarted
# $driveLetter is the drive letter of the volume
# Get the configuration for the next session for the volume
$nextConfig = Get-WMIObject -class UWF_Volume @CommonParams |
where {
$_.DriveLetter -eq "$driveLetter" -and $_.CurrentSession -eq $false
};
# Remove all file and folder exclusions
if ($nextConfig) {
$nextConfig.RemoveAllExclusions() | Out-Null;
Write-Host "Cleared all exclusions for $driveLetter";
} else {
Write-Error "Could not clear exclusions for drive $driveLetter";
}
}
# Some examples of using the functions
Clear-FileExclusions "C:"
Add-FileExclusion "C:" "\Users\Public\Public Documents"
Add-FileExclusion "C:" "\myfolder\myfile.txt"
Get-FileExclusions "C:"
Remove-FileExclusion "C:" "\myfolder\myfile.txt"
Get-FileExclusions "C:"
See Also
Reference
Unified Write Filter WMI provider reference