New batch script to fix messed up installations

Related issues: nmap/nmap#998, nmap/nmap#1216, nmap/nmap#1095

installer/FixInstall.bat

@@ -0,0 +1,94 @@
+@echo off
+rem Start type auto will start the Npcap service at boot. Set this to "demand" for demand start instead.
+set START_TYPE=auto
+
+setlocal ENABLEEXTENSIONS
+
+rem Get the installed configuration
+set KEY_NAME=HKLM\SYSTEM\CurrentControlSet\Services\npcap\Parameters
+for /F "usebackq tokens=1,2*" %%A IN (`reg query "%KEY_NAME%" /v "Dot11Support" 2^>nul ^| find "Dot11Support"`) do (
+	set Dot11Support=%%C
+)
+echo Dot11Support = %Dot11Support%
+for /F "usebackq tokens=1,2*" %%A IN (`reg query "%KEY_NAME%" /v "LoopbackSupport" 2^>nul ^| find "LoopbackSupport"`) do (
+	set LoopbackSupport=%%C
+)
+echo LoopbackSupport = %LoopbackSupport%
+for /F "usebackq tokens=1,2*" %%A IN (`reg query "%KEY_NAME%" /v "WinPcapCompatible" 2^>nul ^| find "WinPcapCompatible"`) do (
+	set WinPcapCompatible=%%C
+)
+echo WinPcapCompatible = %WinPcapCompatible%
+
+rem Make sure we can find where Npcap is installed
+set KEY_NAME=HKLM\Software\WOW6432Node\Npcap
+for /F "usebackq tokens=1,2*" %%A IN (`reg query "%KEY_NAME%" /ve 2^>nul ^| find "(Default)"`) do (
+	set NPCAP_DIR=%%C
+)
+if defined NPCAP_DIR (goto DO_FIX)
+set KEY_NAME=HKLM\Software\Npcap
+for /F "usebackq tokens=1,2*" %%A IN (`reg query "%KEY_NAME%" /ve 2^>nul ^| find "(Default)"`) do (
+	set NPCAP_DIR=%%C
+)
+if defined NPCAP_DIR (goto DO_FIX) else (goto ABORT)
+
+:DO_FIX
+echo NPCAP_DIR = "%NPCAP_DIR%"
+rem Stop the services and set their start types properly
+net stop npcap
+sc.exe config npcap start= %START_TYPE%
+if %Dot11Support% == 0x1 (
+	net stop npcap_wifi
+	rem *_wifi service is disabled at install
+	sc.exe config npcap_wifi start= disabled
+)
+if %WinPcapCompatible% == 0x1 (
+	net stop npf
+	sc.exe config npf start= %START_TYPE%
+	if %Dot11Support% == 0x1 (
+		net stop npf_wifi
+		sc.exe config npf_wifi start= disabled
+	)
+)
+
+rem Remove and reinstall loopback adapters
+if %LoopbackSupport% == 0x1 (
+"%NPCAP_DIR%\NPFInstall.exe" -ul
+)
+rem TODO Remove any leftover adapters in any case
+netsh interface show interface | find "Npcap Loopback Adapter"
+if NOT ERRORLEVEL 1 (
+	echo Some Npcap Loopback Adapter was not removed. Remove it manually:
+	echo 1. In the Device Manager, open 'Network adapters'
+	echo 2. Right-click any 'Npcap Loopback Adapter' and choose 'Uninstall device'
+	echo 3. Repeat until all Npcap Loopback Adapters are removed
+	start devmgmt.msc
+	pause
+)
+
+if %LoopbackSupport% == 0x1 (
+"%NPCAP_DIR%\NPFInstall.exe" -il
+)
+
+rem Restart the services
+net start npcap
+if %WinPcapCompatible% == 0x1 (
+	net start npf
+)
+
+rem Rebind the filters to all adapters
+if %Dot11Support% == 0x1 (
+	"%NPCAP_DIR%\NPFInstall.exe" -r2
+) else (
+	"%NPCAP_DIR%\NPFInstall.exe" -r
+)
+if %WinPcapCompatible% == 0x1 (
+	"%NPCAP_DIR%\NPFInstall2.exe" -r
+)
+
+rem Done!
+goto EOF
+
+:ABORT
+echo "Unable to find or fix your installation"
+
+:EOF