tools/testing/selftests/core/close_range_test.c

// SPDX-License-Identifier: GPL-2.0

#define _GNU_SOURCE
#include <errno.h>
#include <fcntl.h>
#include <linux/kernel.h>
#include <limits.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <syscall.h>
#include <unistd.h>

#include "../kselftest_harness.h"
#include "../clone3/clone3_selftests.h"

#ifndef __NR_close_range
#define __NR_close_range -1
#endif

#ifndef CLOSE_RANGE_UNSHARE
#define CLOSE_RANGE_UNSHARE	(1U << 1)
#endif

static inline int sys_close_range(unsigned int fd, unsigned int max_fd,
				  unsigned int flags)
{
	return syscall(__NR_close_range, fd, max_fd, flags);
}

#ifndef ARRAY_SIZE
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#endif

TEST(close_range)
{
	int i, ret;
	int open_fds[101];

	for (i = 0; i < ARRAY_SIZE(open_fds); i++) {
		int fd;

		fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
		ASSERT_GE(fd, 0) {
			if (errno == ENOENT)
				SKIP(return, "Skipping test since /dev/null does not exist");
		}

		open_fds[i] = fd;
	}

	EXPECT_EQ(-1, sys_close_range(open_fds[0], open_fds[100], -1)) {
		if (errno == ENOSYS)
			SKIP(return, "close_range() syscall not supported");
	}

	EXPECT_EQ(0, sys_close_range(open_fds[0], open_fds[50], 0));

	for (i = 0; i <= 50; i++)
		EXPECT_EQ(-1, fcntl(open_fds[i], F_GETFL));

	for (i = 51; i <= 100; i++)
		EXPECT_GT(fcntl(open_fds[i], F_GETFL), -1);

	/* create a couple of gaps */
	close(57);
	close(78);
	close(81);
	close(82);
	close(84);
	close(90);

	EXPECT_EQ(0, sys_close_range(open_fds[51], open_fds[92], 0));

	for (i = 51; i <= 92; i++)
		EXPECT_EQ(-1, fcntl(open_fds[i], F_GETFL));

	for (i = 93; i <= 100; i++)
		EXPECT_GT(fcntl(open_fds[i], F_GETFL), -1);

	/* test that the kernel caps and still closes all fds */
	EXPECT_EQ(0, sys_close_range(open_fds[93], open_fds[99], 0));

	for (i = 93; i <= 99; i++)
		EXPECT_EQ(-1, fcntl(open_fds[i], F_GETFL));

	EXPECT_GT(fcntl(open_fds[i], F_GETFL), -1);

	EXPECT_EQ(0, sys_close_range(open_fds[100], open_fds[100], 0));

	EXPECT_EQ(-1, fcntl(open_fds[100], F_GETFL));
}

TEST(close_range_unshare)
{
	int i, ret, status;
	pid_t pid;
	int open_fds[101];
	struct clone_args args = {
		.flags = CLONE_FILES,
		.exit_signal = SIGCHLD,
	};

	for (i = 0; i < ARRAY_SIZE(open_fds); i++) {
		int fd;

		fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
		ASSERT_GE(fd, 0) {
			if (errno == ENOENT)
				SKIP(return, "Skipping test since /dev/null does not exist");
		}

		open_fds[i] = fd;
	}

	pid = sys_clone3(&args, sizeof(args));
	ASSERT_GE(pid, 0);

	if (pid == 0) {
		ret = sys_close_range(open_fds[0], open_fds[50],
				      CLOSE_RANGE_UNSHARE);
		if (ret)
			exit(EXIT_FAILURE);

		for (i = 0; i <= 50; i++)
			if (fcntl(open_fds[i], F_GETFL) != -1)
				exit(EXIT_FAILURE);

		for (i = 51; i <= 100; i++)
			if (fcntl(open_fds[i], F_GETFL) == -1)
				exit(EXIT_FAILURE);

		/* create a couple of gaps */
		close(57);
		close(78);
		close(81);
		close(82);
		close(84);
		close(90);

		ret = sys_close_range(open_fds[51], open_fds[92],
				      CLOSE_RANGE_UNSHARE);
		if (ret)
			exit(EXIT_FAILURE);

		for (i = 51; i <= 92; i++)
			if (fcntl(open_fds[i], F_GETFL) != -1)
				exit(EXIT_FAILURE);

		for (i = 93; i <= 100; i++)
			if (fcntl(open_fds[i], F_GETFL) == -1)
				exit(EXIT_FAILURE);

		/* test that the kernel caps and still closes all fds */
		ret = sys_close_range(open_fds[93], open_fds[99],
				      CLOSE_RANGE_UNSHARE);
		if (ret)
			exit(EXIT_FAILURE);

		for (i = 93; i <= 99; i++)
			if (fcntl(open_fds[i], F_GETFL) != -1)
				exit(EXIT_FAILURE);

		if (fcntl(open_fds[100], F_GETFL) == -1)
			exit(EXIT_FAILURE);

		ret = sys_close_range(open_fds[100], open_fds[100],
				      CLOSE_RANGE_UNSHARE);
		if (ret)
			exit(EXIT_FAILURE);

		if (fcntl(open_fds[100], F_GETFL) != -1)
			exit(EXIT_FAILURE);

		exit(EXIT_SUCCESS);
	}

	EXPECT_EQ(waitpid(pid, &status, 0), pid);
	EXPECT_EQ(true, WIFEXITED(status));
	EXPECT_EQ(0, WEXITSTATUS(status));
}

TEST(close_range_unshare_capped)
{
	int i, ret, status;
	pid_t pid;
	int open_fds[101];
	struct clone_args args = {
		.flags = CLONE_FILES,
		.exit_signal = SIGCHLD,
	};

	for (i = 0; i < ARRAY_SIZE(open_fds); i++) {
		int fd;

		fd = open("/dev/null", O_RDONLY | O_CLOEXEC);
		ASSERT_GE(fd, 0) {
			if (errno == ENOENT)
				SKIP(return, "Skipping test since /dev/null does not exist");
		}

		open_fds[i] = fd;
	}

	pid = sys_clone3(&args, sizeof(args));
	ASSERT_GE(pid, 0);

	if (pid == 0) {
		ret = sys_close_range(open_fds[0], UINT_MAX,
				      CLOSE_RANGE_UNSHARE);
		if (ret)
			exit(EXIT_FAILURE);

		for (i = 0; i <= 100; i++)
			if (fcntl(open_fds[i], F_GETFL) != -1)
				exit(EXIT_FAILURE);

		exit(EXIT_SUCCESS);
	}

	EXPECT_EQ(waitpid(pid, &status, 0), pid);
	EXPECT_EQ(true, WIFEXITED(status));
	EXPECT_EQ(0, WEXITSTATUS(status));
}

TEST_HARNESS_MAIN