vshdumpfile.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.
//
//  vshDumpFile.c
//

// This contains some useful functions written for the shell

#include <stdlib.h>
#include <errno.h>
#include <sys/api.h>
#include <sys/vsh.h>


_X_ int vshDumpFile(const char *fileName)
{
  // Desc: Print the contents of the file, specified by 'fileName', to standard output.  'fileName' must be an absolute pathname, beginning with '/'.

  int status = 0;
  unsigned count;
  file theFile;
  char *fileBuffer = NULL;

  // Make sure file name isn't NULL
  if (fileName == NULL)
    return (errno = ERR_NULLPARAMETER);
  
  for (count = 0; count < sizeof(file); count ++)
    ((char *) &theFile)[count] = NULL;

  // Call the "find file" routine to see if we can get the first file
  status = fileFind(fileName, &theFile);
  if (status < 0)
    return (errno = status);

  // Make sure the file isn't empty.  We don't want to try reading
  // data from a nonexistent place on the disk.
  if (theFile.size == 0)
    // It is empty, so just return
    return (status = 0);

  // The file exists and is non-empty.  That's all we care about (we don't 
  // care at this point, for example, whether it's a file or a directory.  
  // Read it into memory and print it on the screen.
  
  // Allocate a buffer to store the file contents in
  fileBuffer = malloc((theFile.blocks * theFile.blockSize) + 1);
  if (fileBuffer == NULL)
    return (errno = ERR_MEMORY);

  status = fileOpen(fileName, OPENMODE_READ, &theFile);
  if (status < 0)
    {
      free(fileBuffer);
      return (errno = status);
    }

  status = fileRead(&theFile, 0, theFile.blocks, fileBuffer);
  if (status < 0)
    {
      free(fileBuffer);
      return (errno = status);
    }

  // Print the file
  for (count = 0; count < theFile.size; count ++)
    {
      // Look out for tab characters
      if (fileBuffer[count] == (char) 9)
	textTab();

      // Look out for newline characters
      else if (fileBuffer[count] == (char) 10)
	textNewline();

      else
	textPutc(fileBuffer[count]);
    }

  // If the file did not end with a newline character...
  if (fileBuffer[count - 1] != '\n')
    textNewline();

  // Free the memory
  free(fileBuffer);

  return (status = 0);
}