#include <iostream>
#include <string.h>
#include <signal.h>
#include <stdio.h>
#include <cstdlib>
#include <unistd.h>

// modified version of Kerrisk's code.

using namespace std;

void catcher(int sig) {
    static int count = 0;

    cout << "Caught a Signal " << sig << " (" << strsignal(sig) << ")" << endl;
    cout << "Call number " << count << endl;
    sleep(1); 

    if (count == 0) {
       count ++;
       cout << "Going to raise another sigusr1 in the call " << endl;
       raise(SIGUSR1);
    }

    cout <<"Done in signal handler " << count  << endl;
    cout << endl;
    return;
}

int main(int argc, char *argv[]) {
    int x, y;
    sigset_t blockSet, prevMask;
    bool blocking;
    struct sigaction sa;

    if (argc > 1 && strchr(argv[1], 'i') != NULL) {
        cout << "Ignoring SIGUSR1" << endl;

        // ok for an ignore
        if (signal(SIGUSR1, SIG_IGN) == SIG_ERR) {
            perror("signal");
	    exit(-1);
	}

    } else if (argc > 1 && strchr(argv[1], 'h') != NULL) {
        cout << "Catching SIGUSR1" << endl;

        sigemptyset(&sa.sa_mask);
        sa.sa_flags = SA_RESTART;
        sa.sa_handler = catcher;

        if (sigaction(SIGUSR1, &sa, NULL) == -1) {
            perror("sigaction");
	    exit (-1);
	}
    }

    blocking = argc > 1 && strchr(argv[1], 'b') != NULL;
    if (blocking) {
        cout << "Blocking SIGUSR1" << endl;

        sigemptyset(&blockSet);
        sigaddset(&blockSet, SIGUSR1);

        if (sigprocmask(SIG_BLOCK, &blockSet, &prevMask) == -1) {
            perror("sigprocmask");
	    exit(-1);
	}
    }

    cout << "About to generate SIGUSR1\n" << endl;
    raise(SIGUSR1);

    if (blocking) {
        cout << "Sleeping before unblocking" << endl;
        sleep(2);

        cout << "Unblocking SIG1PE" << endl;

        if (sigprocmask(SIG_SETMASK, &prevMask, NULL) == -1) {
            perror("sigprocmask");
	    exit(-1);
	}
    }

    cout << "All Done, Exiting " << endl;
    cout << endl;
    return 0;
}