Execute actions before reboot

[TrifonovS]

Hi,
I have a strange issue and I cannot find a solution. My installer calls an external installer (included in it), but sometimes this external installer reboots the PC. I want my installer to execute some actions before the reboot. How it can handle this?

[Anders]

I don't see how you can, ExecWait does not return until the process has completed. Is this a MSI based external installer?

[TrifonovS]

Yes, it is MSI based installer. I know that I cannot do anything inside my installer, but I'm thinking that I can register somewhere another small application (before to call this external installer) that will be called when Windows tries to reboot and it can do the job.But I don't really know how to do it...

[Nutzzz]

MSI installers take the /norestart command line parameter, and return 3010 if install was successful but requires a reboot.

If the installer didn't take a command line parameter, I could think of some wacky hacks like adding a logoff script and then removing it once the script runs, or just removing it without running it if the installer didn't reboot.

[TrifonovS]

Thank you Nutzzz, but ca you explain a little bit the idea of the logoff script. I didn't get it...

[Nutzzz]

Well, since the former method should work for you, that's by far the better solution.

The hacky method I mention is to replicate the method that the group policy editor uses to assign a shutdown script to the machine (or a logoff script for the current user) by using a .reg file with "regedit.exe /s regfile.reg" (and/or a group of WriteRegStr/WriteRegDWORD NSIS commands). See this page for an example .reg file for a startup script.

Your script would be a .bat/.cmd or .vbs file that runs your actions and then applies another .reg file that deletes the registry entries so the shutdown script doesn't run next time around. If you want/need to use NSIS for your actions, you could create another installer or even leverage your uninstaller by calling it with a command line parameter that uses an otherwise unused routine and then immediately quits before the regular uninstall routines begin.

If a reboot isn't performed and execution returns to your installer, then delete the registry entries so that they're never used.

FYI, to delete registry values using a .reg file, assign it an unquoted hyphen (-), e.g.:

code:
[HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\Group Policy\State\Machine\Scripts\Shutdown\0\0]

"Script"=-

"Parameters"=-

"ExecTime"=-

[TrifonovS]

Hi again Nutzzz,
Thanks a lot. This is exactly what I'm searching for.

[TrifonovS]

Hi again!
This doesn't work. When the PC is connected to the network, the group policy is changed by the network server. The problem still occurs. Isn't there another way to catch the reboot without hacks?

[TrifonovS]

One additional question. I found somewhere in Internet that NSIS handles WM_QUERYENDSESSION message and returns FALSE, so it must prevent rebooting from another application. Is there any possibility to execute a function from the script when thos message is received?

[Anders]

One additional question. I found somewhere in Internet that NSIS handles WM_QUERYENDSESSION message and returns FALSE, so it must prevent rebooting from another application. Is there any possibility to execute a function from the script when thos message is received?

Only if you write a custom plug-in. You don't know if Windows is really restarting at that point though.

See also:

https://blogs.msdn.microsoft.com/oldnewthing/20170329-00/?p=95855

[TrifonovS]

Thank you Anders. I want to avoid writing a plug-in, because my knowledge is not enough. However, is it possible to use code like this:

  !include SysFunc.nsh
  !include WinMessages.nsh

  ...
  StrCpy $5 $hwndParent
  ; Create MSG struct
  System::Call "*${stMSG} (_) p.R9"
  ; Get message
  System::Call "${sysGetMessage} (R9, r5,_) .s"
  !insertmacro SINGLE_CALLBACK 1 $R8 1 ShutDownRequest

  ...
  Function ShutDownRequest
    MessageBox MB_OK "NSIS: Shutdown request detected!!!"
  FunctionEnd 

I tried this code, but the installer hangs-up somewhere in these lines. My problem is that this is ready code and I don't understand it completely. Maybe there is an error that I cannot see...

[Anders]

You can't use the system plug-in to do this. I wrote a WndSubClass plug-in a long time ago, it might work.

[TrifonovS]

Hi Anders,
I'm following you advice. I installed the WndSubclass plug-in and also executed the example that comes with it. It works fine, but I still can't understand how to use it for my needs. Sorry for that, but can you give me a next hint?

[TrifonovS]

One more question. I cannot understand from the example why the message is in $2:

  ${If} $2 = ${WM_NCHITTEST}
    ; ...
  ${ElseIf} $2 = ${WM_TIMER}
    ; ...
  ${ElseIf} $2 = ${WM_LBUTTONUP}
    ; ...
  ${EndIf} 

Where it comes the value in $2?

[Anders]

The plug-in uses $1, $2, $3 and $4 so you don't have to pop IIRC.