Unverified Commit de528723 authored by Christian Brauner's avatar Christian Brauner
Browse files

tests: test CLONE_CLEAR_SIGHAND 



Test that CLONE_CLEAR_SIGHAND resets signal handlers to SIG_DFL for the
child process and that CLONE_CLEAR_SIGHAND and CLONE_SIGHAND are
mutually exclusive.

Cc: Florian Weimer <fweimer@redhat.com>
Cc: libc-alpha@sourceware.org
Cc: linux-api@vger.kernel.org
Signed-off-by: default avatarChristian Brauner <christian.brauner@ubuntu.com>
Link: https://lore.kernel.org/r/20191014104538.3096-2-christian.brauner@ubuntu.com
parent b612e5df

MAINTAINERS

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@@ -12826,6 +12826,7 @@ S: Maintained 
T:	git git://git.kernel.org/pub/scm/linux/kernel/git/brauner/linux.git

F:	samples/pidfd/

F:	tools/testing/selftests/pidfd/

F:	tools/testing/selftests/clone3/

K:	(?i)pidfd

K:	(?i)clone3

K:	\b(clone_args|kernel_clone_args)\b

tools/testing/selftests/Makefile

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@@ -4,6 +4,7 @@ TARGETS += bpf 
TARGETS += breakpoints

TARGETS += capabilities

TARGETS += cgroup

TARGETS += clone3

TARGETS += cpufreq

TARGETS += cpu-hotplug

TARGETS += drivers/dma-buf

tools/testing/selftests/clone3/.gitignore

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clone3_clear_sighand

tools/testing/selftests/clone3/Makefile

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# SPDX-License-Identifier: GPL-2.0-only

CFLAGS += -g -I../../../../usr/include/



TEST_GEN_PROGS := clone3_clear_sighand



include ../lib.mk

tools/testing/selftests/clone3/clone3_clear_sighand.c

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/* SPDX-License-Identifier: GPL-2.0 */



#define _GNU_SOURCE

#include <errno.h>

#include <sched.h>

#include <signal.h>

#include <stdio.h>

#include <stdlib.h>

#include <string.h>

#include <unistd.h>

#include <linux/sched.h>

#include <linux/types.h>

#include <sys/syscall.h>

#include <sys/wait.h>



#include "../kselftest.h"



#ifndef CLONE_CLEAR_SIGHAND

#define CLONE_CLEAR_SIGHAND 0x100000000ULL

#endif



#ifndef __NR_clone3

#define __NR_clone3 -1

struct clone_args {

	__aligned_u64 flags;

	__aligned_u64 pidfd;

	__aligned_u64 child_tid;

	__aligned_u64 parent_tid;

	__aligned_u64 exit_signal;

	__aligned_u64 stack;

	__aligned_u64 stack_size;

	__aligned_u64 tls;

};

#endif



static pid_t sys_clone3(struct clone_args *args, size_t size)

{

	return syscall(__NR_clone3, args, size);

}



static void test_clone3_supported(void)

{

	pid_t pid;

	struct clone_args args = {};



	if (__NR_clone3 < 0)

		ksft_exit_skip("clone3() syscall is not supported\n");



	/* Set to something that will always cause EINVAL. */

	args.exit_signal = -1;

	pid = sys_clone3(&args, sizeof(args));

	if (!pid)

		exit(EXIT_SUCCESS);



	if (pid > 0) {

		wait(NULL);

		ksft_exit_fail_msg(

			"Managed to create child process with invalid exit_signal\n");

	}



	if (errno == ENOSYS)

		ksft_exit_skip("clone3() syscall is not supported\n");



	ksft_print_msg("clone3() syscall supported\n");

}



static void nop_handler(int signo)

{

}



static int wait_for_pid(pid_t pid)

{

	int status, ret;



again:

	ret = waitpid(pid, &status, 0);

	if (ret == -1) {

		if (errno == EINTR)

			goto again;



		return -1;

	}



	if (!WIFEXITED(status))

		return -1;



	return WEXITSTATUS(status);

}



static void test_clone3_clear_sighand(void)

{

	int ret;

	pid_t pid;

	struct clone_args args = {};

	struct sigaction act;



	/*

	 * Check that CLONE_CLEAR_SIGHAND and CLONE_SIGHAND are mutually

	 * exclusive.

	 */

	args.flags |= CLONE_CLEAR_SIGHAND | CLONE_SIGHAND;

	args.exit_signal = SIGCHLD;

	pid = sys_clone3(&args, sizeof(args));

	if (pid > 0)

		ksft_exit_fail_msg(

			"clone3(CLONE_CLEAR_SIGHAND | CLONE_SIGHAND) succeeded\n");



	act.sa_handler = nop_handler;

	ret = sigemptyset(&act.sa_mask);

	if (ret < 0)

		ksft_exit_fail_msg("%s - sigemptyset() failed\n",

				   strerror(errno));



	act.sa_flags = 0;



	/* Register signal handler for SIGUSR1 */

	ret = sigaction(SIGUSR1, &act, NULL);

	if (ret < 0)

		ksft_exit_fail_msg(

			"%s - sigaction(SIGUSR1, &act, NULL) failed\n",

			strerror(errno));



	/* Register signal handler for SIGUSR2 */

	ret = sigaction(SIGUSR2, &act, NULL);

	if (ret < 0)

		ksft_exit_fail_msg(

			"%s - sigaction(SIGUSR2, &act, NULL) failed\n",

			strerror(errno));



	/* Check that CLONE_CLEAR_SIGHAND works. */

	args.flags = CLONE_CLEAR_SIGHAND;

	pid = sys_clone3(&args, sizeof(args));

	if (pid < 0)

		ksft_exit_fail_msg("%s - clone3(CLONE_CLEAR_SIGHAND) failed\n",

				   strerror(errno));



	if (pid == 0) {

		ret = sigaction(SIGUSR1, NULL, &act);

		if (ret < 0)

			exit(EXIT_FAILURE);



		if (act.sa_handler != SIG_DFL)

			exit(EXIT_FAILURE);



		ret = sigaction(SIGUSR2, NULL, &act);

		if (ret < 0)

			exit(EXIT_FAILURE);



		if (act.sa_handler != SIG_DFL)

			exit(EXIT_FAILURE);



		exit(EXIT_SUCCESS);

	}



	ret = wait_for_pid(pid);

	if (ret)

		ksft_exit_fail_msg(

			"Failed to clear signal handler for child process\n");



	ksft_test_result_pass("Cleared signal handlers for child process\n");

}



int main(int argc, char **argv)

{

	ksft_print_header();

	ksft_set_plan(1);



	test_clone3_supported();

	test_clone3_clear_sighand();



	return ksft_exit_pass();

}