[MFC] CreateProcess와 CreatePipe를 이용하여 ping command 실행 하고 결과 읽기

Visual Studio 2012

MFC에서 ping command 실행하여 값을 확인해보자.

1. 함수원형은 다음과 같다.

매개변수인 pCmdArg에 기존 명령프롬프트에서 사용하는 명령어를 넣으면 된다.

// ...
CString ExecCmd( LPCSTR pCmdArg);
//...

2. 소스코드

클래스이름에 본인이 작업할 클래스명을 적으면 된다.

Pipe를 통해서 CreateProcess로 만들어진 자식프로세스의 읽기나 쓰기가 가능하다

// ...
CString 클래스이름::ExecCmd( LPCSTR pCmdArg)
{
   //   Handle Inheritance - to pipe child's stdout via pipes to parent, handles must be inherited.
   //   SECURITY_ATTRIBUTES.bInheritHandle must be TRUE
   //   CreateProcess parameter bInheritHandles must be TRUE;
   //   STARTUPINFO.dwFlags must have STARTF_USESTDHANDLES set.
 
   CString strResult; // Contains result of cmdArg.
 
   HANDLE hChildStdoutRd; // Read-side, used in calls to ReadFile() to get child's stdout output.
   HANDLE hChildStdoutWr; // Write-side, given to child process using si struct.
 
   BOOL fSuccess;
 
   // Create security attributes to create pipe.
   SECURITY_ATTRIBUTES saAttr = {sizeof(SECURITY_ATTRIBUTES)} ;
   saAttr.bInheritHandle       = TRUE; // Set the bInheritHandle flag so pipe handles are inherited by child process. Required.
   saAttr.lpSecurityDescriptor = NULL;
 
   // Create a pipe to get results from child's stdout.
   // I'll create only 1 because I don't need to pipe to the child's stdin.
   if ( !CreatePipe(&hChildStdoutRd, &hChildStdoutWr, &saAttr, 0) )
   {
      return strResult;
   }
 
   STARTUPINFO si = { sizeof(STARTUPINFO) }; // specifies startup parameters for child process.
 
   si.dwFlags     = STARTF_USESHOWWINDOW | STARTF_USESTDHANDLES; // STARTF_USESTDHANDLES is Required.
   si.hStdOutput  = hChildStdoutWr; // Requires STARTF_USESTDHANDLES in dwFlags.
   si.hStdError   = hChildStdoutWr; // Requires STARTF_USESTDHANDLES in dwFlags.
   // si.hStdInput remains null.
   si.wShowWindow = SW_HIDE; // Prevents cmd window from flashing. Requires STARTF_USESHOWWINDOW in dwFlags.
 
   PROCESS_INFORMATION pi  = { 0 };
 
   // Create the child process.
   fSuccess = CreateProcess(
      NULL,
      (LPSTR)pCmdArg,     // command line
      NULL,               // process security attributes
      NULL,               // primary thread security attributes
      TRUE,               // TRUE=handles are inherited. Required.
      CREATE_NEW_CONSOLE, // creation flags
      NULL,               // use parent's environment
      NULL,               // use parent's current directory
      &si,                // __in, STARTUPINFO pointer
      &pi);               // __out, receives PROCESS_INFORMATION
 
   if (! fSuccess)
   {
      return strResult;
   }
 
   // Wait until child processes exit. Don't wait forever.
   WaitForSingleObject( pi.hProcess, 2000 );
   TerminateProcess( pi.hProcess, 0 ); // Kill process if it is still running. Tested using cmd "ping blah -n 99"
 
   // Close the write end of the pipe before reading from the read end of the pipe.
   if (!CloseHandle(hChildStdoutWr))
   {
      return strResult;
   }
 
   // Read output from the child process.
   for (;;)
   {
      DWORD dwRead;
      CHAR chBuf[4096];
 
      // Read from pipe that is the standard output for child process.
      bool done = !ReadFile( hChildStdoutRd, chBuf, 4096, &dwRead, NULL) || dwRead == 0;
      if( done )
      {
         break;
      }
 
      // Append result to string.
      strResult += CString( chBuf, dwRead) ;
   }
 
   // Close process and thread handles.
   CloseHandle( hChildStdoutRd );
 
   // CreateProcess docs specify that these must be closed. 
   CloseHandle( pi.hProcess );
   CloseHandle( pi.hThread );
 
   return strResult;
}
//...

3. 테스트 하기

자기 자신을 핑검색 한 후에 검색 내용을 메시지박스로 표현한다.

코드 실행은 다음과 같이 진행한다.

// ...
	CString strResult="";
	strResult = ExecCmd("ping 127.0.0.1");
	AfxMessageBox(strResult);
//...

끝