/* Placed in the public domain by Todd C. Miller on April 30, 2002 */

#include <stdio.h>
#include <stdlib.h>
#include <signal.h>
#include <unistd.h>

void check_oflow(void);
void check_div0(int);
void timedout(int);
void div0_handler(int);
__dead void usage(void);

/*
 * Check signal(SIGFPE, SIG_IGN) for overflow and divide by zero.
 */
int
main(int argc, char **argv)
{
        int ch, oflag, zflag;

        oflag = zflag = 0;
        while ((ch = getopt(argc, argv, "oz")) != -1) {
                switch (ch) {
                case 'o':
                        oflag = 1;
                        break;
                case 'z':
                        zflag = 1;
                        break;
                }
        }

        if (oflag && zflag)
                usage();

        signal(SIGFPE, div0_handler);
        signal(SIGALRM, timedout);

        if (oflag)
                check_oflow();
        else
                check_div0(0);

        exit(0);
}

void
check_oflow(void)
{
        double d, od;

        od = 0;
        d = 256;
        do {
                od = d;
                alarm(10);
                d *= d;
                alarm(0);
        } while (d != od);
}

void
check_div0(int zero)
{
        int i;

        alarm(10);
        i = 1 / zero;
        alarm(0);
}

void
timedout(int sig)
{
        _exit(1);
}

void
div0_handler(int sig)
{
        _exit(0);
}

__dead void
usage(void)
{
        extern char *__progname;

        (void)fprintf(stderr, "usage: %s -o | -z\n", __progname);
        exit(1);
}