mydev.c

在Linux下实现文件的拷贝

#ifndef __KERNEL__
#define __KERNEL__ 
#endif

#ifndef MODULE
#define MODULE     
#endif

#include </home/zhangjian/ostask/linux-2.6.18/include/asm/module.h>
#include <linux/init.h>
#include <linux/fs.h>
#include <linux/kernel.h>
#include <asm/uaccess.h>

#define CHAR_MAJOR_NUM 300	
char msgbuf[256];

static int test_major= 0;
static int dev_open(struct inode *, struct file *);
static int dev_release(struct inode *, struct file *);
static ssize_t dev_read(struct file *, char *, size_t, loff_t *);
static ssize_t dev_write(struct file *, const char *, size_t, loff_t *);

struct file_operations dev_fops =
{
	 open: dev_open,
	 release: dev_release,
  	 read: dev_read,
    write: dev_write,
};

static int dev_init()
{
  
	int result;
      	result=register_chrdev(CHAR_MAJOR_NUM, "mydev", &dev_fops);
 
       	if (result<0)
{
		printk("mydev register failure!");
return result;
}
    if(result==0)
{
		printk("mydev register success!");
test_major=result;
}
	return 0;

}

static void dev_exit()
{
       	unregister_chrdev(CHAR_MAJOR_NUM, "mydev");
}

static int dev_open(struct inode *node, struct file *f)
{                             
       	return 0;
}

static ssize_t dev_release(struct inode *node, struct file *f)
{        
       	return 0;
}

static ssize_t dev_read(struct file *f, char *buf, size_t len, loff_t *off)
{      
	int i;
   for(i=0;i<len;i++)      
      {
      if(__put_user(msgbuf[i],buf++))
        return -EFAULT;
      }
   return len;

}

static ssize_t dev_write(struct file *f, const char *buf,
size_t len, loff_t *off)
{
   int i;
   unsigned char uc;
   printk("Data below is from user.\n");
   for(i=0;i<len;i++)
     { 
     if(!get_user(msgbuf[i],buf++))
        printk("%02x",uc);
    }
   return len;
   }

module_init(dev_init);
module_exit(dev_exit);