Talk:ExecDos plug-in

Use after free

https://sourceforge.net/p/nsis/bugs/1266/

GlobalFree(ptp);

Possible stack corruption

I believe there is a problem with ExecDos corrupting the stack, or corrupting global variables:

Function DatabaseScriptExecuted
	; Stack: <Script.sql> <MyDB> <localhost> <C:\CMDSQL.EXE>
	
	MessageBox MB_OK "$0   $1   $2   $3   $4   $5"
	; Displays: "1422944   0001_TableExists.sql   True   0   1"
	
	Exch $3 ; Database script filename
	; Stack: <Old_$3> <MyDB> <localhost> <C:\CMDSQL.EXE>
	
	Exch
	; Stack: <MyDB> <Old_$3> <localhost> <C:\CMDSQL.EXE>

	Exch $2 ; Database name
	; Stack: <Old_$2> <Old_$3> <localhost> <C:\CMDSQL.EXE>

	Exch 2
	; Stack: <localhost> <Old_$3> <Old_$2> <C:\CMDSQL.EXE>

	Exch $1 ; Database host
	; Stack: <Old_$1> <Old_$3> <Old_$2> <C:\CMDSQL.EXE>

	Exch 3
	; Stack: <C:\CMDSQL.EXE> <Old_$3> <Old_$2> <Old_$1>

	Exch $0 ; SQLCMD.EXE path
	; Stack: <Old_$0> <Old_$3> <Old_$2> <Old_$1>

	Push $4
	; Stack: <Old_$4> <Old_$0> <Old_$3> <Old_$2> <Old_$1>

	Push $5
	; Stack: <Old_$5> <Old_$4> <Old_$0> <Old_$3> <Old_$2> <Old_$1>
	
	ExecDos::exec /DETAILED /TIMEOUT=20000 '"$0" -S $1 -d $2 -Q "select count(*) from dbo.DatabaseScript where ScriptFilename = $\'$3$\'" -o "$PLUGINSDIR\DatabaseScriptExecuted.out"' '' ''
	Pop $4 ; Pop the result off the stack first, before popping rest of saved global variables
	Pop $5
	Pop $4
	Pop $0
	Pop $3
	Pop $2
	Pop $1
	MessageBox MB_OK "$0   $1   $2   $3   $4   $5"
	; Displays: "0   True   0   1422944   1"

Note that if I move the block of script that pops my saved global variables and the message box to BEFORE the call to ExecDos::exec, the global variables are the same as when the function was entered.

It's also interesting to note that nsExec::exec also appears to have this problem.

visualcsharpcoder "at" hotmail dawt com if you want to email me about this problem.

Stack issues: confirmed

Corruption is a strong word: it looks like ExecDos::exec /DETAILED just pushes an extra empty value on the stack:

Name "Test"
OutFile "Test.exe"

Section "Foo"
  Dumpstate::debug
  ; Stack: empty
  ExecDos::exec "c:\windows\system32\ping.exe 127.0.0.1" "" ""
  Dumpstate::debug
  ; Stack: "0"
  ExecDos::exec /DETAILED "c:\windows\system32\ping.exe 127.0.0.1" "" ""
  Dumpstate::debug
  ; Stack: "0", "", "0"
  ; Expected: "0", "0"
SectionEnd

Workaround: When using /DETAILED, Pop to check the exit code, then Pop again to clear out the extra value. I have not checked the behavior of /DETAILED /ASYNC.

I do not see this same behavior using any of the nsExec functions.

66.150.169.146 21:30, 6 November 2008 (UTC)

Takhir: This is feature, not bug. Last parameter is optional, for 'to window' it defines target window handle and not required if window specified by /DETAILED option. Another words - use ExecDos::exec /DETAILED "c:\windows\system32\ping.exe 127.0.0.1" ""

---

Timeouts

TIMEOUT TOTAL execution time, milliseconds, for example /TIMEOUT=10000. Default is big enough. Short timeouts may cause app to

be terminated.

---

And how this Default big is?

Takhir: WINBASE.H(758):#define INFINITE 0xFFFFFFFF // Infinite timeout

An example showing how to redirect the output to the main log window would be great!

Takhir: If we are talking about Detailed window, just use /DETAILED option. Otherwise you should supply window handle. BTW would be better to send requests to NSIS forum. I found these messages today (Febr. 23, 2009) only.

Newbie trying to install ExecDos.dll

• Hi, i been searching for details on this. I read somewhere that i just put the ExecDos.dll into the plugin of NSIS which i did, but to no avail. Compiling my nsi keep returning Invalid command ExecDos::exec. Will appreciate some pointers. Rgds. - Red1

False alarm! I put it in the wrong plugin folder. :D - Red1