On Tue, Dec 22, 2020 at 05:53:12PM -0800, Chang S. Bae wrote:

+static int setup_altstack(void *start, unsigned long size)
+{
+	stack_t ss;
+
+	memset(&ss, 0, sizeof(ss));
+	ss.ss_size = size;
+	ss.ss_sp = start;
+
+	return sigaltstack(&ss, NULL);
+}
+
+static jmp_buf jmpbuf;
+
+static void sigsegv(int sig, siginfo_t *info, void *ctx_void)
+{
+	if (sigalrm_expected) {
+		printf("[FAIL]\tSIGSEGV signal delivery is wrong.\n");

			 	"Wrong signal delivered: SIGSEGV (expected SIGALRM)."

+		nerrs++;
+	} else {
+		printf("[OK]\tSIGSEGV signal is delivered.\n");

					s/is //

+	}
+
+	siglongjmp(jmpbuf, 1);
+}
+
+static void sigalrm(int sig, siginfo_t *info, void *ctx_void)
+{
+	if (!sigalrm_expected) {
+		printf("[FAIL]\tSIGALRM sigal delivery is wrong.\n");

See above.

+		nerrs++;
+	} else {
+		printf("[OK]\tSIGALRM signal is delivered.\n");

Ditto.

+	}
+}
+
+static void test_sigaltstack(void *altstack, unsigned long size)
+{
+	if (setup_altstack(altstack, size))
+		err(1, "sigaltstack()");
+
+	sigalrm_expected = (size > at_minstack_size) ? true : false;
+
+	sethandler(SIGSEGV, sigsegv, 0);
+	sethandler(SIGALRM, sigalrm, SA_ONSTACK);
+
+	if (sigsetjmp(jmpbuf, 1) == 0) {

	if (!sigsetjmp...)

+		printf("[RUN]\tTest an (%s) alternate signal stack\n",

			"Test an alternate signal stack of %ssufficient size.\n"

+		       sigalrm_expected ? "enough" : "too-small");

					 "" : "in");

+		printf("\tRaise SIGALRM. %s is expected to be delivered.\n",
+		       sigalrm_expected ? "It" : "But SIGSEGV");

					"It" : "SIGSEGV"

Drop "But".

Ask if something's not clear.

-- 
Regards/Gruss,
    Boris.

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