Commit 73a3cde9 authored by Thomas Weißschuh's avatar Thomas Weißschuh Committed by Thomas Weißschuh
Browse files

selftests: harness: Implement test timeouts through pidfd 



Make the kselftest harness compatible with nolibc which does not implement
signals by replacing the signal logic with pidfds.
The code also becomes simpler.

Signed-off-by: default avatarThomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: default avatarShuah Khan <skhan@linuxfoundation.org>
Link: https://lore.kernel.org/r/20250505-nolibc-kselftest-harness-v4-7-ee4dd5257135@linutronix.de


Signed-off-by: default avatarThomas Weißschuh <linux@weissschuh.net>
parent 67ee5261

tools/testing/selftests/kselftest_harness.h

+25 −47
Original line number Diff line number Diff line
@@ -56,6 +56,8 @@ 
#include <asm/types.h>

#include <ctype.h>

#include <errno.h>

#include <linux/unistd.h>

#include <poll.h>

#include <stdbool.h>

#include <stdint.h>

#include <stdio.h>
@@ -914,7 +916,6 @@ struct __test_metadata { 
	int exit_code;

	int trigger; /* extra handler after the evaluation */

	int timeout;	/* seconds to wait for test timeout */

	bool timed_out;	/* did this test timeout instead of exiting? */

	bool aborted;	/* stopped test due to failed ASSERT */

	bool setup_completed; /* did setup finish? */

	jmp_buf env;	/* for exiting out of test early */
@@ -964,75 +965,52 @@ static inline void __test_check_assert(struct __test_metadata *t) 
		abort();

}



struct __test_metadata *__active_test;

static void __timeout_handler(int sig, siginfo_t *info, void *ucontext)

{

	struct __test_metadata *t = __active_test;



	/* Sanity check handler execution environment. */

	if (!t) {

		fprintf(TH_LOG_STREAM,

			"# no active test in SIGALRM handler!?\n");

		abort();

	}

	if (sig != SIGALRM || sig != info->si_signo) {

		fprintf(TH_LOG_STREAM,

			"# %s: SIGALRM handler caught signal %d!?\n",

			t->name, sig != SIGALRM ? sig : info->si_signo);

		abort();

	}



	t->timed_out = true;

	/* signal process group */

	kill(-(t->pid), SIGKILL);

}



static void __wait_for_test(struct __test_metadata *t)

{

	struct sigaction action = {

		.sa_sigaction = __timeout_handler,

		.sa_flags = SA_SIGINFO,

	};

	struct sigaction saved_action;

	/*

	 * Sets status so that WIFEXITED(status) returns true and

	 * WEXITSTATUS(status) returns KSFT_FAIL.  This safe default value

	 * should never be evaluated because of the waitpid(2) check and

	 * SIGALRM handling.

	 * timeout handling.

	 */

	int status = KSFT_FAIL << 8;

	int child;

	struct pollfd poll_child;

	int ret, child, childfd;

	bool timed_out = false;



	if (sigaction(SIGALRM, &action, &saved_action)) {

	childfd = syscall(__NR_pidfd_open, t->pid, 0);

	if (childfd == -1) {

		t->exit_code = KSFT_FAIL;

		fprintf(TH_LOG_STREAM,

			"# %s: unable to install SIGALRM handler\n",

			"# %s: unable to open pidfd\n",

			t->name);

		return;

	}

	__active_test = t;

	t->timed_out = false;

	alarm(t->timeout);

	child = waitpid(t->pid, &status, 0);

	if (child == -1 && errno != EINTR) {



	poll_child.fd = childfd;

	poll_child.events = POLLIN;

	ret = poll(&poll_child, 1, t->timeout * 1000);

	if (ret == -1) {

		t->exit_code = KSFT_FAIL;

		fprintf(TH_LOG_STREAM,

			"# %s: Failed to wait for PID %d (errno: %d)\n",

			t->name, t->pid, errno);

			"# %s: unable to wait on child pidfd\n",

			t->name);

		return;

	} else if (ret == 0) {

		timed_out = true;

		/* signal process group */

		kill(-(t->pid), SIGKILL);

	}



	alarm(0);

	if (sigaction(SIGALRM, &saved_action, NULL)) {

	child = waitpid(t->pid, &status, WNOHANG);

	if (child == -1 && errno != EINTR) {

		t->exit_code = KSFT_FAIL;

		fprintf(TH_LOG_STREAM,

			"# %s: unable to uninstall SIGALRM handler\n",

			t->name);

			"# %s: Failed to wait for PID %d (errno: %d)\n",

			t->name, t->pid, errno);

		return;

	}

	__active_test = NULL;



	if (t->timed_out) {

	if (timed_out) {

		t->exit_code = KSFT_FAIL;

		fprintf(TH_LOG_STREAM,

			"# %s: Test terminated by timeout\n", t->name);