samples/bpf: run cleanup routines when receiving SIGTERM

Shahid Habib noticed that when xdp1 was killed from a different console the xdp
program was not cleaned-up properly in the kernel and it continued to forward
traffic.

Most of the applications in samples/bpf cleanup properly, but only when getting
SIGINT.  Since kill defaults to using SIGTERM, add support to cleanup when the
application receives either SIGINT or SIGTERM.
Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Reported-by: Shahid Habib <shahid.habib@broadcom.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

samples/bpf/cookie_uid_helper_example.c

@@ -306,7 +306,9 @@ int main(int argc, char *argv[])
 	prog_attach_iptables(argv[2]);
 	if (cfg_test_traffic) {
 		if (signal(SIGINT, finish) == SIG_ERR)
-			error(1, errno, "register handler failed");
+			error(1, errno, "register SIGINT handler failed");
+		if (signal(SIGTERM, finish) == SIG_ERR)
+			error(1, errno, "register SIGTERM handler failed");
 		while (!test_finish) {
 			print_table();
 			printf("\n");

samples/bpf/offwaketime_user.c

@@ -100,6 +100,7 @@ int main(int argc, char **argv)
 	setrlimit(RLIMIT_MEMLOCK, &r);
 
 	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
 
 	if (load_kallsyms()) {
 		printf("failed to process /proc/kallsyms\n");

samples/bpf/sampleip_user.c

@@ -180,6 +180,7 @@ int main(int argc, char **argv)
 		return 1;
 	}
 	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
 
 	/* do sampling */
 	printf("Sampling at %d Hertz for %d seconds. Ctrl-C also ends.\n",

samples/bpf/trace_event_user.c

@@ -192,6 +192,7 @@ int main(int argc, char **argv)
 	setrlimit(RLIMIT_MEMLOCK, &r);
 
 	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
 
 	if (load_kallsyms()) {
 		printf("failed to process /proc/kallsyms\n");

samples/bpf/tracex2_user.c

@@ -127,6 +127,7 @@ int main(int ac, char **argv)
 	}
 
 	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
 
 	/* start 'ping' in the background to have some kfree_skb events */
 	f = popen("ping -c5 localhost", "r");

samples/bpf/xdp1_user.c

@@ -106,6 +106,7 @@ int main(int argc, char **argv)
 	}
 
 	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
 
 	if (set_link_xdp_fd(ifindex, prog_fd[0], xdp_flags) < 0) {
 		printf("link set xdp fd failed\n");

samples/bpf/xdp_tx_iptunnel_user.c

@@ -244,6 +244,7 @@ int main(int argc, char **argv)
 	}
 
 	signal(SIGINT, int_exit);
+	signal(SIGTERM, int_exit);
 
 	while (min_port <= max_port) {
 		vip.dport = htons(min_port++);