vshpasswordprompt.c

上一个上传的有问题,这个是好的。visopsys包括系统内核和GUI的全部SOURCE code ,还包括一些基本的docs文档。里面src子目录对应所有SOURCE code.对于想研究操作系统的朋

// 
//  Visopsys
//  Copyright (C) 1998-2007 J. Andrew McLaughlin
//  
//  This library is free software; you can redistribute it and/or modify it
//  under the terms of the GNU Lesser General Public License as published by
//  the Free Software Foundation; either version 2.1 of the License, or (at
//  your option) any later version.
//
//  This library is distributed in the hope that it will be useful, but
//  WITHOUT ANY WARRANTY; without even the implied warranty of
//  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
//  General Public License for more details.
//
//  You should have received a copy of the GNU Lesser General Public License
//  along with this library; if not, write to the Free Software Foundation,
//  Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
//
//  vshPasswordPrompt.c
//

// This contains some useful functions written for the shell

#include <sys/vsh.h>
#include <sys/api.h>
#include <stdio.h>


_X_ void vshPasswordPrompt(const char *prompt, char *buffer)
{
  // Desc: Produces a text-mode prompt for the user to enter a password.  The prompt message is the first parameter, and a buffer to contain the result is the second parameter.

  int count = 0;
  int okay = 0;
  
  // Turn keyboard echo off
  textInputSetEcho(0);
  
  while (!okay)
    {
      printf(prompt);
      
      // This loop grabs characters
      for (count = 0; count < 17; count ++)
	{
	  buffer[count] = getchar();
	  
	  if (buffer[count] == (unsigned char) 10)
	    {
	      buffer[count] = '\0';
	      printf("\n");
	      okay = 1;
	      break;
	    }
	  
	  else if (count >= 16)
	    {
	      printf("\nThat password is too long.\n");
	      buffer[0] = '\0';
	      break;
	    }
	  
	  else if (buffer[count] == (unsigned char) 8)
	    {
	      buffer[count] = '\0';
	      if (count > 0)
		{
		  textBackSpace();
		  count -= 2;
		}
	      else
		count -= 1;
	      continue;
	    }
	 
	  else
	    printf("*");
	}
    }

  // Echo back on
  textInputSetEcho(1);

  buffer[16] = '\0';
  return;
}