silo5
3rd April 2009 17:37 UTC

nsExec hangs (reproducible)
  Script compiled with v2.44 running on WinXP SP3 hangs executing nsExec::ExecToStack (and ExeDos).
Necessary conditions include:
- custom page
- ExecToStack is executed in the custom page show function
- the executed program broadcasts a windows SetNonClientMetrics message.

Below you can find two scripts that reproduce this problem.
The second script is written in AutoIt3, it just broadcasts the message.
The first script is NSIS, it execs once in .onInit, which demonstrates that there is no failure (because it's outside the custom page). Then it execs in the custom page show function where it hangs.
You should be seeing exactly four message boxes, but you will actually see only three, one before and one after exec in .onInit, and one before exec in the show function. Then you need to kill _prog.exe which hangs in the background.

_bug.nsi

!include "MUI2.nsh"


>AutoCloseWindow false

WindowIcon on

XPSTYLE on


Name "_bug"

>OutFile "_bug.exe"

>Caption "_bug"


>VIProductVersion "1.0"

>Var program


Page custom Show Leave ""


>!insertmacro MUI_LANGUAGE "English"


>!macro _RunProgram

    MessageBox mb_ok "in function ${__FUNCTION__} line ${__LINE__}..."

   nsExec::ExecToStack $program

    Pop$0

    MessageBox mb_ok "in function ${__FUNCTION__} line ${__LINE__} exec status was $0"

>!macroend

>!define RunProgram `!insertmacro _RunProgram`


Function Show

 ${RunProgram}

>FunctionEnd


>Function Leave

FunctionEnd


>Function .onInit

  InitPluginsDir

  strcpy $program "$EXEDIR\\_prog.exe"

   ${RunProgram}

>FunctionEnd


Section

SectionEnd 

>

_prog.au3

0x1A

>Global Const $HWND_BROADCAST = 0xFFFF

>Global Const $SPI_SETNONCLIENTMETRICS = 42


DllCall("user32.dll", "int", "SendMessage", _

   "hwnd", $HWND_BROADCAST, _

   "uint", $WM_SETTINGCHANGE, _

   "wparam", $SPI_SETNONCLIENTMETRICS, _

   "str", "WindowMetrics" _

>) 

Anders
3rd April 2009 17:57 UTC

*SendMessage is a built-in nsis command, why not just use that?

*you might want to try '"$EXEDIR\_prog.exe"'

*Can AutoIt even produce console programs?

silo5
3rd April 2009 19:59 UTC

The point of my post was to provide some sure way to reproduce this problem, which might even be an NSIS bug. I say might -- only the NSIS developers could say more.

After trimming down all the fat to make the example crispy, it looks obviously artificial, but I can assure you that it is a real problem.

I read other postings where people were reporting obscure issues with nsExec, but no clear ways to reproduce them. Maybe reproduce this problem could lead to solving other people's problems?

Using SendMessage in my installer isn't the point. I've just tried to categorize one type of application which fails with nsExec.

I don't know how to answer your question about AutoIt3. I don't know AutoIt3. This is the first time I use it. Does it matter?

Anders
3rd April 2009 22:09 UTC

I can't reproduce this problem, I get all 4 message boxes (NSIS 2.44, random autoit3 version)

You need to come up with a better example, a SendMessage broadcast can lock up if there is a window in your system that is not processing messages

silo5
4th April 2009 07:45 UTC

Thanks for testing it! Are you on XP, which version? This example locks on two different XP boxes here. I want to test it again in a VM, so I can pair down running processes.

Takhir
4th April 2009 15:07 UTC

Tested on Vista Home Premium SP1, both nsExec and ExecDos worked correct. IMHO ping is simple test CLI application

strcpy $program "ping -n 2 localhost"

should give one second delay. Also might be good to test your sample with ExecWait/Exec first - may be something happens in CLI window. autoit3 might just hang (as Anders already wrote). Or might wait for user input. Earlier we had reports about nsExec hangs only.

Anders
4th April 2009 15:55 UTC

Originally posted by silo5
Thanks for testing it! Are you on XP, which version?

XP SP2

AaronLS
5th April 2009 01:36 UTC

@silo, What options are you using when you compile your AutoIt script?

silo5
6th April 2009 19:33 UTC

AaronLLS, I let SciTE compile it, using whatever are the default compiler options in the standard Scite4AutoIt distribution. I'll be happy to be more precise if you tell me where to look. I really don't know AutoIt. Thanks.