#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <unistd.h>
#include <string.h>


int do_poll_proc(int pid)
{
	char path[64];
	char bufa[2][256] = { };
	int count;

	sprintf(path, "/proc/%d/stat", pid);

	for (count=0; count<10000; count++) {
		int procfd = open(path, O_RDONLY);

		if (procfd >= 0) {
			char *buf = bufa[count % 2];

			read(procfd, buf, 255);
			close(procfd);
			if (memcmp(bufa[0], bufa[1], 255))
				printf("%02d: %s", count, buf);
		} else {
			perror("open proc");
			break;
		}
	}
	return 0;
}


int main(int argc, char *argv[])
{
	int ttyfd;
	int pid, cpid;
	int pdelay = 100;

	if (argc > 1)
		pdelay = atoi(argv[1]);

	pid = getpid();
	cpid = fork();

	switch (cpid) {
	    case -1:
		perror("fork");
		break;

	    case 0:	/* child */
		do_poll_proc(pid);
		exit(0);

	    default:	/* parent */
		usleep(pdelay);
		break;
	}

	ttyfd = open("/dev/tty", O_RDWR);
	if (ttyfd >= 0) {
		int ret = ioctl(ttyfd, TIOCNOTTY, (char *)0);
		if (ret)
			perror("ioctl");
		printf("all is fine ...\n");
		close(ttyfd);
		usleep(1000);
		exit(0);
	}
	exit(1);
}