#include <fcntl.h>
#include <glob.h>
#include <termios.h>
#include <unistd.h>

#include <stdio.h>

int main() {
	glob_t globbuf;
	char ** ttyp;

	glob("/dev/tty*", GLOB_NOSORT, 0, &globbuf);
	ttyp = globbuf.gl_pathv;

	do {
		struct termios options;
		int fd = open(*ttyp, O_RDWR | O_NOCTTY | O_NDELAY);
		if (fd == -1) continue;
		tcgetattr(fd, &options);
		if (!(options.c_lflag & (ISIG | IEXTEN)))
			printf("%s\n", *ttyp);
		close(fd);
	} while (*++ttyp);

	globfree(&globbuf);
	return 0;
}