#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <pthread.h>
#include <signal.h>
#include <unistd.h>
#include <sys/ucontext.h>
#include <malloc.h>
#include <errno.h>

#define SCP_FROM_UCONTEXT(uc) \
    ((struct sigcontext *) &((struct ucontext *)(uc))->uc_mcontext)

static int _traceback_signal = -1;
static pthread_t pid1 = 0;
static pthread_t pid2 = 0;
static pthread_t pidmain = 0;

extern int __libc_allocate_rtsig(int high);

static void tb_sig_handler(int sig, siginfo_t *info, void *ucontext)
{
	struct sigcontext *scp;
	int ret, i;

	printf("\n%s entered\n", __func__);
	printf("thread 0x%lx context\n", pthread_self());
	scp = SCP_FROM_UCONTEXT(ucontext);

	printf("rIP: %16.16lx\n", scp->rip);
	printf("rSP: %16.16lx\n", scp->rsp);
	printf("rBP: %16.16lx\n", scp->rbp);

	printf("\n");
}

void * test_thread1(void *arg)
{
	while(1) {
		sleep(2);
	};
	return NULL;
}

void * test_thread2(void *arg)
{
	while(1) {
		sleep(2);
	};
	return NULL;
}

int main()
{
	struct sigaction act;
	int ret = 0;
	
	_traceback_signal = __libc_allocate_rtsig(1);
	act.sa_sigaction = tb_sig_handler;
	sigemptyset(&act.sa_mask);
	act.sa_flags = SA_RESTART | SA_SIGINFO;
	sigaction(_traceback_signal, &act, NULL);

	ret = pthread_create(&pid1, NULL, test_thread1, NULL);
	if(ret < 0) {
		fprintf(stderr, "thread 1 creation failed\n");
		return -1;
	}
	printf("Thread 1 (0x%lx) created\n", pid1);

	ret = pthread_create(&pid2, NULL, test_thread2, NULL);
	if(ret < 0) {
		fprintf(stderr, "thread 2 creation failed\n");
		return -1;
	}
	printf("Thread 2 (0x%lx) created\n", pid2);

	pidmain = pthread_self();

	printf("Main pid: 0x%lx\n", pidmain);
	
	ret = pthread_kill(pid1, _traceback_signal);
	if(ret >= 0) {
		printf("pid1[0x%lx] signaled\n", pid1);
	}

	sleep(1);
	
	ret = pthread_kill(pid2, _traceback_signal);
	if(ret >= 0) {
		printf("pid2[0x%lx] signaled\n", pid2);
	}

	sleep(1);

#if 0
	ret = pthread_kill(pidmain, _traceback_signal);
	if(ret >= 0) {
		printf("pidmain[0x%lx] signaled\n", pidmain);
	}
#endif

	return 0;
}