#include <assert.h>
#include <signal.h>
#include <stdarg.h>
#include <stdio.h>
#include <sys/time.h>
#include <sys/wait.h>
#include <unistd.h>
sigset_t mkset(int n, ...) {
sigset_t s;
int res = 0;
res |= sigemptyset(&s);
va_list va;
va_start(va, n);
while (n--) {
res |= sigaddset(&s, va_arg(va, int));
}
va_end(va);
assert(!res);
return s;
}
sigset_t sigset_or(sigset_t first, sigset_t second) {
sigset_t out;
int res = sigorset(&out, &first, &second);
assert(!res);
return out;
}
sigset_t sigset_and(sigset_t first, sigset_t second) {
sigset_t out;
int res = sigandset(&out, &first, &second);
assert(!res);
return out;
}
int fork_and_signal(sigset_t s) {
if (pid_t pid = fork()) {
kill(pid, SIGUSR1);
kill(pid, SIGUSR2);
int child_stat;
wait(&child_stat);
return !WIFEXITED(child_stat);
} else {
int sig;
int res = sigwait(&s, &sig);
assert(!res);
fprintf(stderr, "died with sig %d\n", sig);
_exit(0);
}
}
void test_sigwait() {
sigset_t s = sigset_or(mkset(1, SIGUSR1), mkset(1, SIGUSR2));
sigprocmask(SIG_BLOCK, &s, 0);
int res;
res = fork_and_signal(s);
fprintf(stderr, "fork_and_signal with SIGUSR1,2: %d\n", res);
s = sigset_and(s, mkset(1, SIGUSR2));
res = fork_and_signal(s);
fprintf(stderr, "fork_and_signal with SIGUSR2: %d\n", res);
}
int main(void) {
test_sigwait();
return 0;
}