/* $Id: tidminusone.c,v 1.6 2012/09/21 12:38:40 kostik Exp $ */

#include <sys/param.h>
#include <sys/thr.h>
#include <err.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

static long tid;
static volatile int terminate;

static void
siginfo_handler(int signo __unused)
{
}

static void *
dummy(void *arg __unused)
{
	long id;

	if (thr_self(&id) == -1)
		err(1, "thr_self");
	if ((int)id == -1)
		errx(1, "tid == -1");
	tid = id;
	return (NULL);
}

static void *
worker(void *arg __unused)
{
	pthread_t thr;
	void *res;
	int error;

	for (; !terminate;) {
		error = pthread_create(&thr, NULL, dummy, NULL);
		if (error != 0)
			errc(1, error, "pthread_create");
		error = pthread_join(thr, &res);
		if (error != 0)
			errc(1, error, "pthread_join");
	}

	return (NULL);
}

static void
usage(void)
{

	fprintf(stderr, "usage: tidminusone [-n <num of threads>]\n");
	exit(2);
}

int
main(int argc, char *argv[])
{
	pthread_t *pthrs;
	sigset_t sigs;
	struct sigaction sa;
	int ch, error, i, nthreads, sig;

	nthreads = 1;
	while ((ch = getopt(argc, argv, "n:")) != -1) {
		switch (ch) {
		case 'n':
			nthreads = atoi(optarg);
			printf("Using %d threads\n", nthreads);
			break;
		case '?':
		default:
			usage();
		}
	}

	bzero(&sa, sizeof(sa));
	sa.sa_handler = siginfo_handler;
	if (sigaction(SIGINFO, &sa, NULL) == -1)
		err(1, "sigaction");
	sigemptyset(&sigs);
	sigaddset(&sigs, SIGINFO);
	sigaddset(&sigs, SIGTERM);
	sigaddset(&sigs, SIGINT);
	error = pthread_sigmask(SIG_BLOCK, &sigs, NULL);
	if (error != 0)
		errc(1, error, "pthread_sigmask");

	pthrs = calloc(nthreads, sizeof(pthread_t));
	for (i = 0; i < nthreads; i++) {
		error = pthread_create(&pthrs[i], NULL, worker, NULL);
		if (error != 0)
			errc(1, error, "pthread_create");
	}

	for (; !terminate;) {
		error = sigwait(&sigs, &sig);
		if (error != 0)
			errc(1, error, "sigwait");
		switch (sig) {
		case SIGINFO:
			printf("Tid 0x%lx\n", tid);
			break;
		default:
			terminate = 1;
			break;
		}
	}

	for (i = 0; i < nthreads; i++) {
		error = pthread_join(pthrs[i], NULL);
		if (error != 0)
			errc(1, error, "pthread_join");
	}
	return (0);
}