exercise2.c

#include<linux/module.h>
#include<linux/kernel.h>
#include<linux/proc_fs.h>
#include<linux/sched.h>
#include<linux/uaccess.h>

#define STRINGLEN 1024

char global_buffer[STRINGLEN];
struct proc_dir_entry *example_dir,*zhang_file,*keke_file;

int proc_read_zhang(char *page,char **start,off_t off,int count,int *eof,void *data)
{
	int len;
	len=sprintf(page,"pid: %d\n",current->pid);
	return len;
}

int proc_read_keke(char *page,char **start,off_t off,int count,int *eof,void *data)
{
	int len;
	len=sprintf(page,"write: %s \n",global_buffer);
	return len;
}

int proc_write_keke(struct file *file,const char *buffer,unsigned long count,void *data)
{
	int len;
	if(count>=STRINGLEN)
		len=STRINGLEN-1;
	else
		len=count;
	copy_from_user(global_buffer,buffer,len);
	global_buffer[len]='\0';
	return len;
}

int init_module()
{
	example_dir=proc_mkdir("13081070",NULL);
	zhang_file=create_proc_read_entry("zhang",0644,example_dir,proc_read_zhang,NULL);
	keke_file=create_proc_entry("keke",0666,example_dir);
	strcpy(global_buffer,"keke");
	keke_file->read_proc=proc_read_keke;
	keke_file->write_proc=proc_write_keke;	
	return 0;
}

void cleanup_module()
{
	remove_proc_entry("zhang",example_dir);
	remove_proc_entry("keke",example_dir);
	remove_proc_entry("13081070",NULL);
}