popen.c

ReactOS是一些高手根据Windows XP的内核编写出的类XP。内核实现机理和API函数调用几乎相同。甚至可以兼容XP的程序。喜欢研究系统内核的人可以看一看。

/*
 * COPYRIGHT:   See COPYING in the top level directory
 * PROJECT:     ReactOS system libraries
 * FILE:        lib/crt/??????
 * PURPOSE:     Unknown
 * PROGRAMER:   Unknown
 * UPDATE HISTORY:
 *              25/11/05: Created
 */

#include <precomp.h>
#include <tchar.h>

#define NDEBUG
#include <internal/debug.h>


/*
 * @implemented
 */
FILE *_tpopen (const _TCHAR *cm, const _TCHAR *md) /* program name, pipe mode */
{
  _TCHAR *szCmdLine=NULL;
  _TCHAR *szComSpec=NULL;
  _TCHAR *s;
  FILE *pf;
  HANDLE hReadPipe, hWritePipe;
  BOOL result;
  STARTUPINFO StartupInfo;
  PROCESS_INFORMATION ProcessInformation;
  SECURITY_ATTRIBUTES sa = {sizeof(SECURITY_ATTRIBUTES), NULL, TRUE};

  TRACE(MK_STR(_tpopen)"('%"sT"', '%"sT"')\n", cm, md);

  if (cm == NULL)
    return( NULL );

  szComSpec = _tgetenv(_T("COMSPEC"));
  if (szComSpec == NULL)
  {
    szComSpec = _T("cmd.exe");
  }

  s = max(_tcsrchr(szComSpec, '\\'), _tcsrchr(szComSpec, '/'));
  if (s == NULL)
    s = szComSpec;
  else
    s++;

  szCmdLine = malloc((_tcslen(s) + 4 + _tcslen(cm) + 1) * sizeof(_TCHAR));
  if (szCmdLine == NULL)
  {
    return NULL;
  }

  _tcscpy(szCmdLine, s);
  s = _tcsrchr(szCmdLine, '.');
  if (s)
    *s = 0;
  _tcscat(szCmdLine, _T(" /C "));
  _tcscat(szCmdLine, cm);

  if ( !CreatePipe(&hReadPipe,&hWritePipe,&sa,1024))
  {
    free (szCmdLine);
    return NULL;
  }

  memset(&StartupInfo, 0, sizeof(STARTUPINFO));
  StartupInfo.cb = sizeof(STARTUPINFO);

  if (*md == 'r' ) {
	StartupInfo.hStdOutput = hWritePipe;
	StartupInfo.dwFlags |= STARTF_USESTDHANDLES;
  }
  else if ( *md == 'w' ) {
	StartupInfo.hStdInput = hReadPipe;
	StartupInfo.dwFlags |= STARTF_USESTDHANDLES;
  }

  result = CreateProcess(szComSpec,
	                  szCmdLine,
			  NULL,
			  NULL,
			  TRUE,
			  0,
			  NULL,
			  NULL,
			  &StartupInfo,
			  &ProcessInformation);
  free (szCmdLine);

  if (result == FALSE)
  {
    CloseHandle(hReadPipe);
    CloseHandle(hWritePipe);
    return NULL;
  }

  CloseHandle(ProcessInformation.hThread);

  if ( *md == 'r' )
    {
      pf = _tfdopen(alloc_fd(hReadPipe,  split_oflags(_fmode)) , _T("r"));
      CloseHandle(hWritePipe);
    }
  else
    {
      pf = _tfdopen( alloc_fd(hWritePipe, split_oflags(_fmode)) , _T("w"));
      CloseHandle(hReadPipe);
    }

  pf->_tmpfname = ProcessInformation.hProcess;

  return( pf );
}

#ifndef _UNICODE

/*
 * @implemented
 */
int _pclose (FILE *pp)
{
  TRACE("_pclose(%x)",pp);

  fclose(pp);
  if (!TerminateProcess(pp->_tmpfname ,0))
    return( -1 );
  return( 0 );
}

#endif