_system.c

来自「一个类似windows」· C语言 代码 · 共 115 行

/* $Id: _system.c 21262 2006-03-08 23:27:16Z audit $
 *
 * COPYRIGHT:   See COPYING in the top level directory
 * PROJECT:     ReactOS system libraries
 * FILE:        lib/msvcrt/process/system.c
 * PURPOSE:     Excutes a shell command
 * PROGRAMER:   Boudewijn Dekker
 * UPDATE HISTORY:
 *              04/03/99: Created
 */

#include <precomp.h>
#include <stdlib.h>
#include <string.h>
#include <process.h>

/*
 * @implemented
 */
int system(const char *command)
{
  char *szCmdLine = NULL;
  char *szComSpec = NULL;

  PROCESS_INFORMATION ProcessInformation;
  STARTUPINFOA StartupInfo;
  char *s;
  BOOL result;

  int nStatus;

  szComSpec = getenv("COMSPEC");

// system should return 0 if command is null and the shell is found

  if (command == NULL) {
      if (szComSpec == NULL)
	return 0;
      else
	return -1;
    }

// should return 127 or 0 ( MS ) if the shell is not found
// __set_errno(ENOENT);

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

  /* split the path from shell command */
  s = max(strrchr(szComSpec, '\\'), strrchr(szComSpec, '/'));
  if (s == NULL)
    s = szComSpec;
  else
    s++;

  szCmdLine = malloc(strlen(s) + 4 + strlen(command) + 1);
  if (szCmdLine == NULL)
  {
     __set_errno(ENOMEM);
     return -1;
  }

  strcpy(szCmdLine, s);
  s = strrchr(szCmdLine, '.');
  if (s)
    *s = 0;
  strcat(szCmdLine, " /C ");
  strcat(szCmdLine, command);

//command file has invalid format ENOEXEC

  memset (&StartupInfo, 0, sizeof(StartupInfo));
  StartupInfo.cb = sizeof(StartupInfo);
  StartupInfo.lpReserved= NULL;
  StartupInfo.dwFlags = STARTF_USESHOWWINDOW;
  StartupInfo.wShowWindow = SW_SHOWDEFAULT;
  StartupInfo.lpReserved2 = NULL;
  StartupInfo.cbReserved2 = 0;

// According to ansi standards the new process should ignore  SIGINT and SIGQUIT
// In order to disable ctr-c the process is created with CREATE_NEW_PROCESS_GROUP,
// thus SetConsoleCtrlHandler(NULL,TRUE) is made on behalf of the new process.


//SIGCHILD should be blocked aswell

  result = CreateProcessA(szComSpec,
	                  szCmdLine,
			  NULL,
			  NULL,
			  TRUE,
			  CREATE_NEW_PROCESS_GROUP,
			  NULL,
			  NULL,
			  &StartupInfo,
			  &ProcessInformation);
  free(szCmdLine);

  if (result == FALSE)
  {
	_dosmaperr(GetLastError());
     return -1;
  }

  CloseHandle(ProcessInformation.hThread);

// system should wait untill the calling process is finished
  _cwait(&nStatus,(int)ProcessInformation.hProcess,0);
  CloseHandle(ProcessInformation.hProcess);

  return nStatus;
}