#include <stdio.h>
#include <libunwind.h>

void show_stack_by_direct_access(long * stack_p, int num) {
	long * cur_stack_p;
	int i;
	cur_stack_p = stack_p;
	for(i = 0; i < num; i++) {
		printf("0x%lx ", *cur_stack_p);
		cur_stack_p = cur_stack_p - 1;
	}
}

int third_function(int num, int num2) {

        unw_cursor_t cursor;
        unw_context_t context;
        unw_proc_info_t proc_info;

	int reg_ip_ok, reg_sp_ok, proc_name_ok;

        size_t name_size = 255;
        char name[255];

	unw_word_t ip, sp;
	unw_word_t greg;

	printf("... the last parameters should be %i and %i.\n", num, num2);

	printf("Back tracing...\n\n");	
	
	unw_tdep_getcontext(&context);
	unw_init_local(&cursor, &context);

	do {
		proc_name_ok = unw_get_proc_name(&cursor, (char *)&name, name_size, NULL);
		if(proc_name_ok == 0) {
			printf("function %s(...)\n", name);
			reg_ip_ok = unw_get_reg(&cursor, UNW_REG_IP, &ip);
			reg_sp_ok = unw_get_reg(&cursor, UNW_REG_SP, &sp);
			if(reg_ip_ok == 0 && reg_sp_ok == 0) {
				printf("ip = 0x%lx, sp = 0x%lx\n",  
				(long) ip, (long) sp);
			}
			else {
				printf("Error getting IP and/or SP register(s).");
			}
			printf("stack: "); 
			show_stack_by_direct_access((long *)sp, 8);
			printf(" ...\n\n");
		}
        } while (unw_step(&cursor) > 0); 

	printf("backtrace finished.\n\n");	
}

int second_function(int num, int num2) {
	third_function(num + 1, num2 * 2);
}

int first_function(int num) {
	second_function(num * 2, num + 1);
}

int main(int argc, char ** argv) {

	int pid;
	printf("Testing basic features of libunwind.\n");
	first_function(2);
	return 0;
}