/*kprobe_example.c*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/kprobes.h>
#include <linux/kallsyms.h>
#include <linux/sched.h>

#define PROBE_FILENAME	"/root/test/uprobe"
#define TEXT_START 	0x8048150
#define TEXT_OFFSET 	0x150
#define PROBE_POS	0x8048304
/*For each probe you need to allocate a kprobe structure*/
struct uprobe  uprobe_ex;

/*kprobe pre_handler: called just before the probed instruction is executed*/
int handler_pre(struct kprobe *p, struct pt_regs *regs)
{
        printk("passed: prehandler executed \n");

        return 0;
}

/*kprobe post_handler: called after the probed instruction is executed*/
void handler_post(struct kprobe *p, struct pt_regs *regs, unsigned long flags)
{
	printk("passed: post handler executed \n");
}

/* fault_handler: this is called if an exception is generated for any
 * instruction within the pre- or post-handler, or when Kprobes
 * single-steps the probed instruction.
 */
int handler_fault(struct kprobe *p, struct pt_regs *regs, int trapnr)
{
        printk("passed: page fault executed \n");
        return 0;
}

int init_module(void)
{
        int ret;
	char *pname = PROBE_FILENAME;

	uprobe_ex.kp.pre_handler = handler_pre;
        uprobe_ex.kp.post_handler = handler_post;
        uprobe_ex.kp.fault_handler = handler_fault;
	//uprobe_ex.kp.opcode = 0;

        uprobe_ex.kp.addr = (kprobe_opcode_t*)PROBE_POS;
	uprobe_ex.offset = (PROBE_POS - TEXT_START + TEXT_OFFSET);
	uprobe_ex.pathname = pname;

        if ((ret = register_uprobe(&uprobe_ex) < 0)) {
                printk("register_uprobe failed, returned %d\n", ret);
                return -1;
        }
        printk("uprobe registered\n");
        return 0;
}

void cleanup_module(void)
{
        unregister_uprobe(&uprobe_ex);
        printk("uprobe unregistered\n");
}

MODULE_LICENSE("GPL");