int main(int argc,char *argv[])
{
struct sigaction sa;
print_sigmask(stdout,"Signal mask at startup: \n");
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
sa.sa_handler = handler;
if (sigaction(SIGINT,&sa,NULL) == -1) {
perror("sigaction failed");
exit(-1);
}
#ifdef USE_SIGSETJMP
printf("Calling sigsetjmp to set a jump-point\n");
if (sigsetjmp(senv,1) == 0) {
#else
printf("Calling setjmp to set a jump-point\n");
if (setjmp(env) == 0) {
#endif
canJump = 1;
} else {
print_sigmask(stdout,"After jump from handler,signal mask is: \n");
}
for (;;)
pause();
}
int
main(int argc, char *argv[])
{
int sleep_time;
struct sigaction sa;
sigset_t block_mask;
sleep_time = (argc > 1) ? atoi(argv[1]) : 5;
if (sleep_time <= 0) {
fprintf(stderr, "sleep-time %s > 0\n", argv[1]);
exit(EXIT_FAILURE);
}
sa.sa_handler = handler;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGCONT, &sa, NULL) == -1) {
perror("sigaction");
exit(EXIT_FAILURE);
}
sigemptyset(&block_mask);
sigaddset(&block_mask, SIGCONT);
if (sigprocmask(SIG_BLOCK, &block_mask, NULL) == -1) {
perror("sigprocmask");
exit(EXIT_FAILURE);
}
printf("set signal mask SIGCONT\n");
print_sigmask(stdout, "SIGNAL MASK:\n");
printf("sleep %ds.\n", sleep_time);
printf("type <Ctrl-Z>. Then, type 'kill -CONT %ld\n", (long) getpid());
sleep(sleep_time);
printf("sleep finished.\n");
print_sigmask(stdout, "SIGNAL MASK:\n");
print_pending_sigs(stdout, "PENDINGS:\n");
printf("unset signal mask SIGCONT\n");
if (sigprocmask(SIG_UNBLOCK, &block_mask, NULL) == -1) {
perror("sigprocmask");
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}
static void handler(int sig)
{
printf("Received signal %d (%s)\n", sig, strsignal(sig));
printf("signal mask is:\n");
print_sigmask(stdout,NULL);
if (!canJump) {
printf("'env' buffer not yet set,doing a simple return");
return;
}
#ifdef USE_SIGSETJMP
siglongjmp(senv,1);
#else
longjmp(env,1);
#endif
}
static void
handler(int sig)
{
/* UNSAFE: This handler uses non-async-signal-safe functions
* (printf(), strsignal(), print_sigmask(); see section 21.1.2) */
printf("Received signal %d (%s), signal mask is:\n",
sig, strsignal(sig));
print_sigmask(stdout, NULL);
if (!can_jump) {
printf("'env' buffer not yet set, doing a simple return\n");
return;
}
#ifdef USE_SIGSETJMP
siglongjmp(senv, 1);
#else
longjmp(env, 1);
#endif
}
