#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/init.h>
#include <asm/uaccess.h>

static long lib_addr;
module_param(lib_addr, long, 0);
MODULE_PARM_DESC(lib_addr, "lib_addr");



static unsigned long parse_elf64(unsigned long start_loc)
{
	Elf64_Ehdr * ehdr;
	int ret = 0;

	ehdr = kmalloc(sizeof(Elf64_Ehdr), GFP_KERNEL);
	if (copy_from_user((void *)ehdr, (void *) start_loc, sizeof(Elf64_Ehdr))) {
		printk("cannot get Elf64_Ehdr from "
		       "start_loc %lx\n", start_loc);
			goto out;
	}
	if (ehdr->e_ident[EI_CLASS] != ELFCLASS64) {
		printk("EI_CLASS of Elf64_Hdr is incorrect! %d\n",
		       ehdr->e_ident[EI_CLASS]);
		goto out;
	}
	if (ehdr->e_type != ET_DYN) {
		printk(KERN_INFO "LPA: "
		       "%s, line %d: Unexpected e_type %u parsing ELF\n",
		       __FUNCTION__, __LINE__, ehdr->e_type);
		goto out;
	}
	ret = ehdr->e_ident[EI_CLASS];
	printk(KERN_INFO "Elf class from Ehdr is %d\n", ret);
 out:
	return ret;
}

static unsigned long parse_elf32(unsigned long start_loc)
{
	Elf32_Ehdr ehdr;
	int ret = 0;

	if (copy_from_user(&ehdr, (void *) start_loc, sizeof (ehdr)))
		goto out;
	if (ehdr.e_ident[EI_CLASS] != ELFCLASS32)
		goto out;
	if (ehdr.e_type != ET_DYN) {
		printk(KERN_INFO
		       "%s, line %d: Unexpected e_type %u parsing ELF\n",
		       __FUNCTION__, __LINE__, ehdr.e_type);
		goto out;
	}
	ret = ehdr.e_ident[EI_CLASS];
	printk(KERN_INFO "Elf class from Ehdr is %d\n", ret);
 out:
	return ret;

}

int find_ehdr(unsigned long start_loc)
{
	int ret = 0;
	if (!(ret = parse_elf32(start_loc)))
		ret = parse_elf64(start_loc);
	return ret;
}



int __init init_module(void)
{
	if (!(find_ehdr(lib_addr))) {
		printk(KERN_INFO "uaccess test failed\n");
		return -1;
	}
	    printk(KERN_INFO "uaccess test succeeded\n");
        return 0;
}

void __exit cleanup_module(void)
{
}
MODULE_LICENSE("GPL");