+#include <lunaix/lunistd.h>
+#include <lunaix/proc.h>
+#include <lunaix/signal.h>
+#include <lunaix/spike.h>
+#include <lunaix/syslog.h>
+#include <lunaix/types.h>
+
+LOG_MODULE("SIGDEMO")
+
+void __USER__
+sigchild_handler(int signum)
+{
+ kprintf(KINFO "SIGCHLD received\n");
+}
+
+void __USER__
+sigsegv_handler(int signum)
+{
+ pid_t pid = getpid();
+ kprintf(KWARN "SIGSEGV received on process %d\n", pid);
+ _exit(signum);
+}
+
+void __USER__
+sigalrm_handler(int signum)
+{
+ pid_t pid = getpid();
+ kprintf(KWARN "I, pid %d, have received an alarm!\n", pid);
+}
+
+void __USER__
+_signal_demo_main()
+{
+ signal(_SIGCHLD, sigchild_handler);
+ signal(_SIGSEGV, sigsegv_handler);
+ signal(_SIGALRM, sigalrm_handler);
+
+ alarm(5);
+
+ int status;
+ pid_t p = 0;
+
+ kprintf(KINFO "Child sleep 3s, parent pause.\n");
+ if (!fork()) {
+ sleep(3);
+ _exit(0);
+ }
+
+ pause();
+
+ kprintf("Parent resumed on SIGCHILD\n");
+
+ for (int i = 0; i < 5; i++) {
+ pid_t pid = 0;
+ if (!(pid = fork())) {
+ signal(_SIGSEGV, sigsegv_handler);
+ sleep(i);
+ if (i == 3) {
+ i = *(int*)0xdeadc0de; // seg fault!
+ }
+ kprintf(KINFO "%d\n", i);
+ _exit(0);
+ }
+ kprintf(KINFO "Forked %d\n", pid);
+ }
+
+ while ((p = wait(&status)) >= 0) {
+ short code = WEXITSTATUS(status);
+ if (WIFSIGNALED(status)) {
+ kprintf(KINFO "Process %d terminated by signal, exit_code: %d\n",
+ p,
+ code);
+ } else if (WIFEXITED(status)) {
+ kprintf(KINFO "Process %d exited with code %d\n", p, code);
+ } else {
+ kprintf(KWARN "Process %d aborted with code %d\n", p, code);
+ }
+ }
+
+ kprintf("done\n");
+
+ spin();
+}
\ No newline at end of file