#Requires -Version 5.1
<#
    JbTecWiz Support Centre -- generated fix script

    Fault : HTTP 500.19 -- the configuration file cannot be read
    Fix   : Grant the app pool identity read access
    Source: https://jbtecwiz.com/support/srv-iis-500-19

    Run as     : Elevated PowerShell
    Expect     : 10 minutes
    Risk       : low
    Reversible : yes

    WHEN THIS IS THE RIGHT FIX
    0x80070005 -- access denied reading the config.

    HOW TO UNDO IT
    icacls with /remove for the identity you granted.

    This script walks the fix one step at a time and asks before each
    one. Steps with no command are things you do yourself -- it prints
    those and waits. Run with -DryRun to print without executing.

    --------------------------------------------------------------------
    NO WARRANTY - USE AT YOUR OWN RISK

    This script is provided by JbTecWiz as-is and with no warranty of any
    kind, express or implied. You run it entirely at your own risk.

    JbTecWiz accepts no liability for any loss or damage arising from its
    use, including but not limited to data loss, downtime, or configuration
    changes that turn out to be wrong for your system.

    You are responsible for reading this script before running it, for
    satisfying yourself that it suits the machine in front of you, and for
    having a working backup first. Some steps cannot be undone.
    --------------------------------------------------------------------
#>

[CmdletBinding()]
param(
    # Print every step and command without running anything.
    [switch]$DryRun,
    # Do not ask before each step. Read the script first if you use this.
    [switch]$Unattended
)

$ErrorActionPreference = 'Stop'
$script:Failed = 0

function Write-Rule { param([string]$Text)
    Write-Host ''
    Write-Host ('-' * 70) -ForegroundColor DarkGray
    if ($Text) { Write-Host $Text -ForegroundColor Cyan }
}

function Show-Prose { param([string]$Text, [string]$Colour = "Gray")
    if (-not $Text) { return }
    $words = $Text -split "\s+"; $line = "  "
    foreach ($w in $words) {
        if (($line.Length + $w.Length) -gt 74) { Write-Host $line -ForegroundColor $Colour; $line = "  " }
        $line += "$w "
    }
    if ($line.Trim()) { Write-Host $line -ForegroundColor $Colour }
}

function Invoke-Step {
    param(
        [int]$Number, [string]$Do, [string]$Why,
        [scriptblock]$Command, [switch]$Manual, [string]$Shell = "powershell"
    )
    Write-Rule "  Step $Number of 3"
    Show-Prose $Do "White"
    if ($Why) { Write-Host ""; Show-Prose $Why "DarkGray" }

    if ($Manual) {
        Write-Host ''
        Write-Host '  -> Do this yourself, then press Enter to carry on.' -ForegroundColor Yellow
        if (-not $Unattended -and -not $DryRun) { [void](Read-Host) }
        return
    }

    Write-Host ''
    foreach ($l in ($Command.ToString().Trim() -split "`n")) {
        Write-Host ("    " + $l.Trim()) -ForegroundColor Green
    }
    Write-Host ''

    if ($DryRun) { Write-Host "  (dry run -- not executed)" -ForegroundColor DarkGray; return }
    if (-not $Unattended) {
        $a = Read-Host "  Run this step? [Y]es / [S]kip / [Q]uit"
        if ($a -match "^[Qq]") { Write-Host "  Stopped at your request."; exit 0 }
        if ($a -match "^[Ss]") { Write-Host "  Skipped." -ForegroundColor DarkGray; return }
    }
    try { & $Command }
    catch {
        $script:Failed++
        Write-Host ("  Step $Number failed: " + $_.Exception.Message) -ForegroundColor Red
        Show-Prose "The rest of the fix may depend on this. Read the write-up before carrying on." "Red"
        if (-not $Unattended) {
            $c = Read-Host "  Carry on anyway? [y/N]"
            if ($c -notmatch "^[Yy]") { exit 1 }
        }
    }
}

Write-Rule
Write-Host '  HTTP 500.19 -- the configuration file cannot be read' -ForegroundColor White
Write-Host '  Grant the app pool identity read access' -ForegroundColor Cyan
Write-Host ''
Write-Host '  Risk: low   Reversible   10 minutes'
Write-Host ''
Show-Prose 'No warranty. Use at your own risk - JbTecWiz accepts no liability. Read it before you run it, and have a backup.' 'DarkYellow'
Write-Rule

if (-not $Unattended -and -not $DryRun) {
    $go = Read-Host '  Ready? [y/N]'
    if ($go -notmatch "^[Yy]") { Write-Host "  Nothing was changed."; exit 0 }
}

Invoke-Step -Number 1 -Do 'Find which pool the site uses and what identity it runs as.' -Command {
    Get-Website | Select-Object Name, ApplicationPool, PhysicalPath
    Get-ItemProperty 'IIS:\AppPools\DefaultAppPool' -Name processModel.identityType
}

Invoke-Step -Number 2 -Do 'Grant read to the pool''s virtual account.' -Why 'An app pool runs as IIS AppPool\<poolname>, a virtual account that exists only on this machine. Granting IUSR or Everyone is the usual wrong turn -- it works and it is far more access than needed.' -Command {
    cmd.exe /c 'icacls "C:\inetpub\wwwroot\site" /grant "IIS AppPool\DefaultAppPool:(OI)(CI)(RX)" /T'
}

Invoke-Step -Number 3 -Do 'Also grant read to IIS_IUSRS if the application needs it.' -Command {
    cmd.exe /c 'icacls "C:\inetpub\wwwroot\site" /grant "IIS_IUSRS:(OI)(CI)(RX)" /T'
}

Write-Rule "  Confirm it worked"
Show-Prose 'The site loads and the failed request trace shows no access denied.' 'White'

Write-Rule
if ($script:Failed -gt 0) {
    Write-Host ("  Finished with " + $script:Failed + " failed step(s).") -ForegroundColor Yellow
    Show-Prose 'Read the full write-up at https://jbtecwiz.com/support/srv-iis-500-19' 'Yellow'
} else {
    Write-Host '  Finished.' -ForegroundColor Green
}
Write-Host ''
Show-Prose 'To undo: icacls with /remove for the identity you granted.' 'DarkGray'
Write-Rule