ko/kprobe_trace.c

#include <linux/kobject.h>
#include <linux/string.h>
#include <linux/sysfs.h>
#include <linux/module.h>
#include <linux/init.h>

struct test_struct {
	int val;
	int arr[3];
	int *parr;
	char name[8];
	char *pname;
};

void test_func1(struct test_struct *p);
void test_func2(struct test_struct p);

void test_func1(struct test_struct *p)
{
	printk("%d\n", p->val);
	printk("%s\n", p->name);
	printk("%s\n", p->pname);
	printk("%d\n", p->arr[1]);
	printk("%d\n", p->parr[1]);
}

void test_func2(struct test_struct p)
{
	printk("%d\n", p.val);
	printk("%s\n", p.name);
	printk("%s\n", p.pname);
	printk("%d\n", p.arr[1]);
	printk("%d\n", p.parr[1]);
}

static ssize_t foo_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
	struct test_struct a;

	a.val = 10;
	sprintf(a.name, "hwc");
	a.pname="njit";

	for (int i = 0; i < 3; i++)
		a.arr[i] = i;
	a.parr = a.arr;

	test_func1(&a);
	test_func2(a);

	return 0;
}

static struct kobj_attribute foo_attribute =
	__ATTR(foo, 0444, foo_show, NULL);

static struct attribute *attrs[] = {
	&foo_attribute.attr,
	NULL,
};

static struct attribute_group attr_group = {
	.attrs = attrs,
};

static struct kobject *example_kobj;
static int __init example_init(void)
{
	int retval;

	example_kobj = kobject_create_and_add("kprobe_ftrace", kernel_kobj);
	if (!example_kobj)
		return -ENOMEM;

	retval = sysfs_create_group(example_kobj, &attr_group);
	if (retval)
		kobject_put(example_kobj);

	return retval;
}
static void __exit example_exit(void)
{
	kobject_put(example_kobj);
}
module_init(example_init);
module_exit(example_exit);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Greg Kroah-Hartman <greg@kroah.com>");