1#include <linux/kernel.h>
2#include <linux/module.h>
3#include <linux/fs.h>
4#include <linux/uio.h>
5#include <linux/kprobes.h>
6
7/*
8 * Jumper probe for do_fork.
9 * Mirror principle enables access to arguments of the probed routine
10 * from the probe handler.
11 */
12
13/* Proxy routine having the same arguments as actual do_fork() routine */
14long jdo_fork(unsigned long clone_flags, unsigned long stack_start,
15	      struct pt_regs *regs, unsigned long stack_size,
16	      int __user * parent_tidptr, int __user * child_tidptr)
17{
18	printk("jprobe: clone_flags=0x%lx, stack_size=0x%lx, regs=%p\n",
19	       clone_flags, stack_size, regs);
20	/* Always end with a call to jprobe_return(). */
21	jprobe_return();
22
23	return 0;
24}
25
26static struct jprobe my_jprobe = {
27	.entry = jdo_fork
28};
29
30static int __init jprobe_init(void)
31{
32	int ret;
33	my_jprobe.kp.symbol_name = "do_fork";
34
35	if ((ret = register_jprobe(&my_jprobe)) < 0) {
36		printk("register_jprobe failed, returned %d\n", ret);
37		/* XXX: Exit code is wrong. */
38		return -1;
39	}
40	printk("Planted jprobe at %p, handler addr %p\n",
41	       my_jprobe.kp.addr, my_jprobe.entry);
42	return 0;
43}
44
45static void __exit jprobe_exit(void)
46{
47	unregister_jprobe(&my_jprobe);
48	printk("jprobe unregistered\n");
49}
50
51module_init(jprobe_init)
52    module_exit(jprobe_exit)
53    MODULE_LICENSE("GPL");
54