/* timing diagnostic for DF-2949 rig alignment */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <fcntl.h>
#include <string.h>
#include <signal.h>
#include <sys/ioctl.h>
#include <sys/types.h>
#include <sys/wait.h>
#include <sys/time.h>

static int gopipe[2];

static double
now(void)
{
	struct timeval tv;
	gettimeofday(&tv, NULL);
	return (tv.tv_sec + tv.tv_usec / 1e6);
}

static void
victim(int id)
{
	char c;
	unsigned int seed = getpid() * 2654435761u;
	int fd;
	double tgo, t0, t1;

	signal(SIGHUP, SIG_IGN);
	fd = open("/dev/tty", O_RDWR);
	read(gopipe[0], &c, 1);
	tgo = now();
	usleep(rand_r(&seed) % 4000);
	t0 = now();
	if (fd >= 0)
		close(fd);
	t1 = now();
	{
		char buf[128];
		int n = snprintf(buf, sizeof(buf),
				 "V%d go=%.6f start=%.6f end=%.6f fd=%d\n",
				 id, tgo, t0, t1, fd);
		int df = open("/tmp/diag.log", O_WRONLY | O_APPEND | O_CREAT, 0644);
		if (df >= 0) { write(df, buf, n); close(df); }
	}
	_exit(0);
}

int
main(int argc, char **argv)
{
	long iters = (argc > 1) ? atol(argv[1]) : 200;
	long k;

	pipe(gopipe);
	unlink("/tmp/diag.log");
	for (k = 0; k < iters; k++) {
		pid_t l = fork();
		if (l == 0) {
			char sname[128];
			if (setsid() < 0) _exit(1);
			int m = posix_openpt(O_RDWR | O_NOCTTY);
			if (m < 0) _exit(1);
			char *s = ptsname(m);
			if (s == NULL) _exit(1);
			snprintf(sname, sizeof(sname), "%s", s);
			int sl = open(sname, O_RDWR | O_NOCTTY);
			if (sl < 0) _exit(1);
			if (ioctl(sl, TIOCSCTTY, 0) < 0) _exit(1);
			for (int v = 0; v < 2; v++) {
				pid_t p = fork();
				if (p == 0)
					victim(v);
			}
			char c;
			read(gopipe[0], &c, 1);
			double tg = now();
			_exit(0);		/* leader exit */
		}
		double tg = now();
		write(gopipe[1], "ggg", 3);
		int st;
		double t0 = now();
		waitpid(l, &st, 0);
		double t1 = now();
		if (k < 20)
			fprintf(stderr, "L go->reap %.6f -> %.6f = %.6f s\n",
				tg, t1, t1 - tg);
	}
	system("cat /tmp/diag.log | tail -8");
	return (0);
}