02. copy_to_user 寫入資料

02. copy_to_user 寫入資料

    char *memory_buffer;
    ssize_t memory_read(struct file *filp, char *buf, 
                        size_t count, loff_t *f_pos) { 
     
      /* Transfering data to user space */ 
      if(memory_buffer==null){
          memory_buffer = kmalloc(1, GFP_KERNEL);
      }
      copy_to_user(buf,memory_buffer,1);
    
      /* Changing reading position as best suits */ 
      if (*f_pos == 0) { 
        *f_pos+=1; 
        return 1; 
      } else { 
        return 0; 
      }
    }