Got “The system cannot find the file specified” when I run NETSH from CreateProcess but it works ok on Command Prompt?

Question

I have an NT service that calls a console program written in Delphi 7, let's call it failover.exe that in turn calls NETSH using a procedure I found:

procedure ExecConsoleApp(CommandLine: ansistring; Output, Errors: TStringList); 

Note: ExecConsoleApp uses CreateProcess, see the following link for full code: http://www.delphisources.ru/pages/faq/base/createprocess_console.html

I would pass the following to CommandLine before calling ExecConsoleApp:

cmd.exe /c "C:\Windows\system32\netsh.exe interface delete address "Wireless Network Connection" 192.168.0.36" 

ExecConsoleApp will return an error:

The system cannot find the file specified

But if I were to run it in Command Prompt, it runs perfectly.

The strange thing is that I remembered it working on the first attempt on that 2003 Server, but after that, it failed regardless of the number of times I tried. In one of the attempt, I've also tried assigning logon as administrator user to the service but to no avail. Neither does fiddling with file security help.

I don't have a Win 2003 server to test with in office, but I have tested it on XP and Win7 and ExecConsoleApp works perfectly, although on XP, I had to amend ExecConsoleApp to execute from system32\wbem in order for it work work:

 Res := CreateProcess(nil, PChar(CommandLine), nil, nil, True,
  // **** Attention: Amended by to point current directory to system32\wbem, this is to solve an error returned by netsh.exe if not done otherwise.
 //   CREATE_NEW_CONSOLE or NORMAL_PRIORITY_CLASS, @env, nil, si, pi);
   CREATE_NEW_CONSOLE or NORMAL_PRIORITY_CLASS, @env, pchar(GetSystemPath(WindRoot) + 'system32\wbem'), si, pi);

I've researched for a day but no clues, hope someone can help. Thanks.

Additional remarks -

1. Server is 32 bit Win2k3.

2. Tried domain administrator, doesn't work.

3. Code snippets:

   Procedure ExecConsoleApp(CommandLine: ansistring; Output, Errors: TStringList);
     var
       sa: TSECURITYATTRIBUTES;
       si: TSTARTUPINFO;
       pi: TPROCESSINFORMATION;
       hPipeOutputRead: THANDLE;
       hPipeOutputWrite: THANDLE;
       hPipeErrorsRead: THANDLE;
       hPipeErrorsWrite: THANDLE;
       Res, bTest: boolean;
       env: array[0..100] of char;
       szBuffer: array[0..256] of char;
       dwNumberOfBytesRead: DWORD;
       Stream: TMemoryStream;
     begin
       sa.nLength := sizeof(sa);
       sa.bInheritHandle := True;
       sa.lpSecurityDescriptor := nil;
       CreatePipe(hPipeOutputRead, hPipeOutputWrite, @sa, 0);
       CreatePipe(hPipeErrorsRead, hPipeErrorsWrite, @sa, 0);
       ZeroMemory(@env, SizeOf(env));
       ZeroMemory(@si, SizeOf(si));
       ZeroMemory(@pi, SizeOf(pi));
       si.cb := SizeOf(si);
       si.dwFlags := STARTF_USESHOWWINDOW or STARTF_USESTDHANDLES;
       si.wShowWindow := SW_HIDE;
       si.hStdInput := 0;
       si.hStdOutput := hPipeOutputWrite;
       si.hStdError := hPipeErrorsWrite;
   
     (* Remember that if you want to execute an app with no parameters you nil the
        second parameter and use the first, you can also leave it as is with no
        problems.                                                                 *)
       Res := CreateProcess(nil, PChar(CommandLine), nil, nil, True,
       CREATE_NEW_CONSOLE or NORMAL_PRIORITY_CLASS, @env, nil, si, pi);
   
   
       // Procedure will exit if CreateProcess fail
       if not Res then
       begin
         CloseHandle(hPipeOutputRead);
         CloseHandle(hPipeOutputWrite);
         CloseHandle(hPipeErrorsRead);
         CloseHandle(hPipeErrorsWrite);
         Exit;
       end;
       CloseHandle(hPipeOutputWrite);
       CloseHandle(hPipeErrorsWrite);
   
       //Read output pipe
       Stream := TMemoryStream.Create;
       try
         while True do
         begin
           bTest := ReadFile(hPipeOutputRead, szBuffer, 256, dwNumberOfBytesRead, nil);
           if not bTest then
           begin
             break;
           end;
           OemToAnsi(szBuffer, szBuffer);
           Stream.Write(szBuffer, dwNumberOfBytesRead);
         end;
         Stream.Position := 0;
         Output.LoadFromStream(Stream);
       finally
         Stream.Free;
       end;
   
       //Read error pipe
       Stream := TMemoryStream.Create;
       try
         while True do
         begin
           bTest := ReadFile(hPipeErrorsRead, szBuffer, 256, dwNumberOfBytesRead, nil);
           if not bTest then
           begin
             break;
           end;
           OemToAnsi(szBuffer, szBuffer);
           Stream.Write(szBuffer, dwNumberOfBytesRead);
         end;
         Stream.Position := 0;
         Errors.LoadFromStream(Stream);
       finally
         Stream.Free;
       end;
   
       WaitForSingleObject(pi.hProcess, INFINITE);
       CloseHandle(pi.hProcess);
       CloseHandle(hPipeOutputRead);
       CloseHandle(hPipeErrorsRead);
     end;
   
   
     cmdstring :=
       'cmd.exe /c "' + GetSystemPath(WindRoot) + 'system32\netsh.exe interface ' +
       ip + ' delete address "' + NetworkInterfaceName + '" ' + VirtualFailoverIPAddress + '"';
   
     logstr('cmdstring: ' + cmdstring);
     ExecConsoleApp(cmdstring, OutP, ErrorP);
   
     if OutP.Text <> '' then
     begin
       logstr('Delete IP Result: ' + OutP.Text);
     end
     else
     begin
       logstr('Delete IP Error: ' + ErrorP.Text);
     end;
   

4. Tried running netsh.exe directly instead of "cmd.exe /c C:\Windows\system32\netsh.exe...", and got the same "The system cannot find the file specified." error. I also accidentally discovered that if I were to issue a wrong netsh command, netsh will actually return an error, e.g.

netsh interface ip delete address "LocalArea Connection" 10.40.201.65

Invalid interface LocalArea Connection specified.

The following is returned if i correct the typo "LocalArea" to "Local Area". netsh interface ip delete address "Local Area Connection" 10.40.201.65

The system cannot find the file specified.

Again, I must repeat that the same command works perfectly fine if I issue it via Command Prompt instead of from my application.

Answer 1

Have you tried this?

if not CreateProcess(PChar('C:\Windows\system32\netsh.exe'), PChar(Arguments), ...) then
begin
  // Do somehting with `GetLastError`
end;

Of course it would be better to detect the path of C:\Windows\system32 at runtime as this could be on another driver or in another directory.

When you run it this way you can get an error message from Windows using the GetLastError call right after CreateProcess.

The ExecConsoleApp procedure is flawed, because it doesn't return the GetLastError or even any indication that CreateProcess failed.

You should fix this first. Maybe add raise EExecConsoleAppCreateProcessFailed.Create(SysErrorMessage(GetLastError)) before Exit to the code.

You shouldn't use cmd.exe /c as a prefix. It's redundant and it makes error diagnostics more difficult. GetLastError might not reflect the correct error code, because you're delegating the creation of the acutal netsh.exe process to cmd.

Answer 2

The "cannot find the file specified" error may also occur if an implicitly loaded DLL required by the executable is not available. In this situation, that is the most likely cause - some essential DLL is not being found when netsh.exe is being run in a non-interactive context.

Use Process Monitor (available for download from Microsoft's web site) to record the file system operations that are taking place during the attempt. Look for file not found errors either in the context of your service process or in the context of the netsh.exe process.