Installs the given hotfix via powershell

Install-Hotfix.ps1

<#
.Synopsis
    Installs the given hotfix
#>
function Install-Hotfix
{
    param(
        [Parameter(Mandatory=$true)]
            [string] $Url,
        [Parameter(Mandatory=$true)]
            [string] $HotfixId
    )

    $downloadedFile = Download -Url $Url

    $logFile = $downloadedFile + ".log"
    function InvokeWusa {
        Write-Log "Installing $downloadedFile..."

        $process = [System.Diagnostics.Process]::Start('wusa.exe', "/quiet /norestart /log:$logFile $downloadedFile")

        if (!$process.WaitForExit(30 * 60 * 1000)) { # wait for 30 min
            throw "Installing $HotfixId timed out; exiting..."
        }

        Write-Log "Install completed (wusa.exe exit code: $($process.ExitCode))"

        return $process
    }

    $process = InvokeWusa

    #
    # 0x8024800c ("The data store section could not be locked within the allotted time") may indicate a conflict with
    # Windows Update, so we stop the service and try one more time.
    #
    $windowsUpdate = 'Windows Update'

    if ($process.ExitCode -eq 0x8024800c -and ((Get-Service $windowsUpdate).Status -eq 'Running')) {
        Write-Log 'Install had a conflict with Windows Update; will retry.'
        Write-Log 'Stopping Windows Update service...'
        Stop-Service $windowsUpdate -Force -Verbose
        try {
            InvokeWusa > $null
        }
        finally {
            Write-Log 'Restarting Windows Update service...'
            Start-Service $windowsUpdate -ErrorAction Continue -Verbose
        }
    }
}

<#
.Synopsis
   Tests whether the given hotfix is installed
#>
function Test-Hotfix
{
    [CmdletBinding()]
    [OutputType([bool])]
    param(
        [Parameter(Mandatory=$true,Position = 0)]
            [string] $HotfixId
    )

    [bool](Get-Hotfix -Id $HotfixId -ErrorAction SilentlyContinue)
}


<#
.Synopsis

    Returns the download info for WMF, which is a hashtable with these items:

        HotfixId - Name of the WMF hotfix 
        Url      - Url of the WMF hotfix 
#>
function Get-WmfDownloadInfo
{
    param(
        [parameter(mandatory=$true)]
        [string] $WmfVersion
    )

    $osVersion = GetOSVersion
    
    Write-Log 'Retrieving WMF download information...'
    Write-Log "    WMF Version: $WmfVersion"
    Write-Log "    OS Version : $($osVersion.Version)"
    Write-Log "    Server OS  : $($osVersion.IsServer)"
    Write-Log "    64-bit OS  : $($osVersion.IsX64)"

    if ($osVersion.IsX64) {
        $arch = 'x64'
    } else {
        $arch = 'x86'
    }

    $key = 'WMF_{0}-Windows_{1}-{2}' -f $WmfVersion, $osVersion.Version, $arch

    $downloadInfo = $script:wmfDownloadInfo[$key]

    if (!$downloadInfo)
    {
        throw New-HandlerTerminatingError $DSC_Status.OsVersionNotSupported
    }

    $downloadInfo
}

#
# Downloads the given URL to a local file and outputs the path to the file
#
function Download
{
    param([Parameter(Mandatory=$true)][string] $Url)

    $webClient = $null

    try 
    {
        $uri = [URI] $url

        $update = $uri.Segments[$uri.Segments.Count - 1]
        
        $localFile = '{0}\{1}' -f $DSC_MainWorkingFolder, $update

        if (Test-Path $localFile) {
            throw New-HandlerTerminatingError `
                -Code $DSC_Status.WmfInstallError.Code `
                -Message ($DSC_Status.WmfInstallError.Message -f $update, (GetLogDirectory))
        }

        Write-Log "Downloading $Url ..."
    
        $webClient = New-Object System.Net.WebClient

        $webClient.DownloadFile($Url, $localFile)

        $localFile

    }
    finally
    {
        if ($webClient) {
            $webClient.Dispose()
        }
    }
}