main.cpp

telnet客户端编程

///////////////////////////////////////////////////////////////////////////////
//
// File:
//        main.cpp
// 
// Purpose:
//        This file provdes the main entry point for the project, and all the
//        global scope support routines.
//
// Notes:
//        This file expects to be linked without the C-Runtime. If compiling,
//        please force the entry point symbol to be "main", and do not link in
//        the default librarys.
//        This means that no c-runtime functions can be used anywhere in the
//        project. I expect this will also exclude any MFC based additions.
//
///////////////////////////////////////////////////////////////////////////////

#include <windows.h>
#include <winsock.h>
#include <process.h>

#include "telnet.h"

///////////////////////////////////////////////////////////////////////////////

//
// Our simple replacement for the c-runtime includes getting the stdin,
// stdout & stderr handles, and providing new and delete operators, that work
// with the win32 heap functions.
//

//
// standard handles needed for CRT emulation
//
HANDLE hHeap;
HANDLE stdin;
HANDLE stdout;
HANDLE stderr;

//
// new will use the win32 heap functions.
//
void* operator new(unsigned int nSize)
{
  return HeapAlloc(hHeap,0,nSize);
}

//
// delete operator provides all memory de-allocation.
// HeapFree doesn't accept NULL.
//
void operator delete(void* pMem)
{
  if(pMem) HeapFree(hHeap,0,pMem);
}

//DWORD NumberOfBytes;
//#define print(s) WriteFile(stdout, s, lstrlen(s), &NumberOfBytes,NULL)
//#define input(s) ReadFile(stdin, s, 255, &NumberOfBytes, NULL)

///////////////////////////////////////////////////////////////////////////////

void err(char const* s,...)
{
  char buf[1024];
  wvsprintf(buf,s,(char*)(s+sizeof(int)));
  DWORD nout;
  WriteFile(stderr,"Error: ",7,&nout,NULL);
  WriteFile(stderr,buf,lstrlen(buf),&nout,NULL);
  WriteFile(stderr,"\r\n\r\n",4,&nout,NULL);
#ifdef _DEBUG
  OutputDebugString(buf);
  OutputDebugString("\n");
#endif
  ExitProcess(0);
}

////////////////////////////////////////////

void main()
{

///////////////////////////////////////
// CRT emulation init
  // Get the IO handles
  stdin = GetStdHandle(STD_INPUT_HANDLE);
  stdout = GetStdHandle(STD_OUTPUT_HANDLE);
  stderr = GetStdHandle(STD_ERROR_HANDLE);

  // Get the heap 
  hHeap = GetProcessHeap();

// Explicitly force the console into a good mode (actually all we are doing is turning
// mouse input off.
  SetConsoleMode(stdin,ENABLE_LINE_INPUT | ENABLE_ECHO_INPUT | ENABLE_PROCESSED_INPUT);

///////////////////////////////////////
// Init winsock
  WSADATA wd;
  int errn;
  if(errn = WSAStartup(0x0101,&wd))
    err(sockmsg(errn));

  LPTSTR pszCommandLine = GetCommandLine();
  char name[256];
  int port = IPPORT_TELNET;

  // Strip out the exe name
  while( *pszCommandLine && (*pszCommandLine != ' '))
    pszCommandLine++;

  // And any spaces after it.
  while( *pszCommandLine && (*pszCommandLine == ' '))
    pszCommandLine++;

  // No parameter given: Abort with error
  if(!*pszCommandLine)
    err("syntax: telnet <hostname> [<port>]");
  
  //Get the remote host name
  char* tmp = name;
  while(*pszCommandLine && (*pszCommandLine != ' '))
    *tmp++ = *pszCommandLine++;
  *tmp = 0;
    
  // Strip excess spaces. (again)
  while( *pszCommandLine && (*pszCommandLine == ' '))
    pszCommandLine++;

  //Get the port number if present.
  if(*pszCommandLine)
  if(*pszCommandLine >= '0' && *pszCommandLine < '9')
  {
    port = 0;
    while(*pszCommandLine && (*pszCommandLine != ' '))
      port = port*10 + *pszCommandLine++ -48;
  }
  else
  {
    _tag_well_known_port_numbers* wkpn = well_known_port_numbers;
    while(wkpn->port && lstrcmpi(wkpn->keyword,pszCommandLine))wkpn++;
    port = wkpn->port;
  }

  if(!port)
    err("Invalid port specified");

  // Give ourselves a neato title.
  char title[256];
  wsprintf(title,"connecting to %s:%i",name,port);
  SetConsoleTitle(title);

  // guess what this does.
  telnet(name,port);

  //Bye bye...
  WSACleanup();

  //Exit process terminates any waiting threads.
  // (Its the CRT that makes a process close when the main thread exits.
  // The WinAPI will leave the process as is for as long as it has a 
  // thread any thread.
  ExitProcess(0);
}