tools/testing/selftests/signal/sas.c

Source file repositories/reference/linux-study-clean/tools/testing/selftests/signal/sas.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/signal/sas.c
Extension
.c
Size
4839 bytes
Lines
198
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

struct stk_data {
	char msg[128];
	int flag;
};

void my_usr1(int sig, siginfo_t *si, void *u)
{
	char *aa;
	int err;
	stack_t stk;
	struct stk_data *p;

	if (sp < (unsigned long)sstack ||
			sp >= (unsigned long)sstack + stack_size) {
		ksft_exit_fail_msg("SP is not on sigaltstack\n");
	}
	/* put some data on stack. other sighandler will try to overwrite it */
	aa = alloca(1024);
	assert(aa);
	p = (struct stk_data *)(aa + 512);
	strcpy(p->msg, msg);
	p->flag = 1;
	ksft_print_msg("[RUN]\tsignal USR1\n");
	err = sigaltstack(NULL, &stk);
	if (err) {
		ksft_exit_fail_msg("sigaltstack() - %s\n", strerror(errno));
		exit(EXIT_FAILURE);
	}
	if (stk.ss_flags != SS_DISABLE)
		ksft_test_result_fail("tss_flags=%x, should be SS_DISABLE\n",
				stk.ss_flags);
	else
		ksft_test_result_pass(
				"sigaltstack is disabled in sighandler\n");
	swapcontext(&sc, &uc);
	ksft_print_msg("%s\n", p->msg);
	if (!p->flag) {
		ksft_exit_fail_msg("[RUN]\tAborting\n");
		exit(EXIT_FAILURE);
	}
}

void my_usr2(int sig, siginfo_t *si, void *u)
{
	char *aa;
	struct stk_data *p;

	ksft_print_msg("[RUN]\tsignal USR2\n");
	aa = alloca(1024);
	/* dont run valgrind on this */
	/* try to find the data stored by previous sighandler */
	p = memmem(aa, 1024, msg, strlen(msg));
	if (p) {
		ksft_test_result_fail("sigaltstack re-used\n");
		/* corrupt the data */
		strcpy(p->msg, msg2);
		/* tell other sighandler that his data is corrupted */
		p->flag = 0;
	}
}

static void switch_fn(void)
{
	ksft_print_msg("[RUN]\tswitched to user ctx\n");
	raise(SIGUSR2);
	setcontext(&sc);
}

int main(void)
{
	struct sigaction act;
	stack_t stk;
	int err;

	/* Make sure more than the required minimum. */
	stack_size = getauxval(AT_MINSIGSTKSZ) + SIGSTKSZ;
	ksft_print_msg("[NOTE]\tthe stack size is %u\n", stack_size);

	ksft_print_header();
	ksft_set_plan(3);

	sigemptyset(&act.sa_mask);
	act.sa_flags = SA_ONSTACK | SA_SIGINFO;
	act.sa_sigaction = my_usr1;
	sigaction(SIGUSR1, &act, NULL);
	act.sa_sigaction = my_usr2;
	sigaction(SIGUSR2, &act, NULL);
	sstack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE,
		      MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, -1, 0);
	if (sstack == MAP_FAILED) {

Annotation

Implementation Notes