Unverified Commit 9d87b106 authored by Christian Brauner's avatar Christian Brauner
Browse files

selftests: add tests for mntns iteration 

Test that forward and backward iteration works correctly.

Link: https://lore.kernel.org/r/20241213-work-mount-rbtree-lockless-v3-8-6e3cdaf9b280@kernel.org


Reviewed-by: default avatarJeff Layton <jlayton@kernel.org>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent cae73d3b

tools/testing/selftests/filesystems/nsfs/.gitignore

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

owner

pidns

iterate_mntns

tools/testing/selftests/filesystems/nsfs/Makefile

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

TEST_GEN_PROGS := owner pidns

TEST_GEN_PROGS := owner pidns iterate_mntns



CFLAGS := -Wall -Werror

tools/testing/selftests/filesystems/nsfs/iterate_mntns.c

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// SPDX-License-Identifier: GPL-2.0-or-later

// Copyright (c) 2024 Christian Brauner <brauner@kernel.org>



#define _GNU_SOURCE

#include <fcntl.h>

#include <sched.h>

#include <stdio.h>

#include <string.h>

#include <sys/stat.h>

#include <sys/mount.h>

#include <unistd.h>



#include "../../kselftest_harness.h"



#define MNT_NS_COUNT 11

#define MNT_NS_LAST_INDEX 10



struct mnt_ns_info {

	__u32 size;

	__u32 nr_mounts;

	__u64 mnt_ns_id;

};



#define MNT_NS_INFO_SIZE_VER0 16 /* size of first published struct */



/* Get information about namespace. */

#define NS_MNT_GET_INFO _IOR(0xb7, 10, struct mnt_ns_info)

/* Get next namespace. */

#define NS_MNT_GET_NEXT _IOR(0xb7, 11, struct mnt_ns_info)

/* Get previous namespace. */

#define NS_MNT_GET_PREV _IOR(0xb7, 12, struct mnt_ns_info)



FIXTURE(iterate_mount_namespaces) {

	int fd_mnt_ns[MNT_NS_COUNT];

	__u64 mnt_ns_id[MNT_NS_COUNT];

};



FIXTURE_SETUP(iterate_mount_namespaces)

{

	for (int i = 0; i < MNT_NS_COUNT; i++)

		self->fd_mnt_ns[i] = -EBADF;



	/*

	 * Creating a new user namespace let's us guarantee that we only see

	 * mount namespaces that we did actually create.

	 */

	ASSERT_EQ(unshare(CLONE_NEWUSER), 0);



	for (int i = 0; i < MNT_NS_COUNT; i++) {

		struct mnt_ns_info info = {};



		ASSERT_EQ(unshare(CLONE_NEWNS), 0);

		self->fd_mnt_ns[i] = open("/proc/self/ns/mnt", O_RDONLY | O_CLOEXEC);

		ASSERT_GE(self->fd_mnt_ns[i], 0);

		ASSERT_EQ(ioctl(self->fd_mnt_ns[i], NS_MNT_GET_INFO, &info), 0);

		self->mnt_ns_id[i] = info.mnt_ns_id;

	}

}



FIXTURE_TEARDOWN(iterate_mount_namespaces)

{

	for (int i = 0; i < MNT_NS_COUNT; i++) {

		if (self->fd_mnt_ns[i] < 0)

			continue;

		ASSERT_EQ(close(self->fd_mnt_ns[i]), 0);

	}

}



TEST_F(iterate_mount_namespaces, iterate_all_forward)

{

	int fd_mnt_ns_cur, count = 0;



	fd_mnt_ns_cur = fcntl(self->fd_mnt_ns[0], F_DUPFD_CLOEXEC);

	ASSERT_GE(fd_mnt_ns_cur, 0);



	for (;; count++) {

		struct mnt_ns_info info = {};

		int fd_mnt_ns_next;



		fd_mnt_ns_next = ioctl(fd_mnt_ns_cur, NS_MNT_GET_NEXT, &info);

		if (fd_mnt_ns_next < 0 && errno == ENOENT)

			break;

		ASSERT_GE(fd_mnt_ns_next, 0);

		ASSERT_EQ(close(fd_mnt_ns_cur), 0);

		fd_mnt_ns_cur = fd_mnt_ns_next;

	}

	ASSERT_EQ(count, MNT_NS_LAST_INDEX);

}



TEST_F(iterate_mount_namespaces, iterate_all_backwards)

{

	int fd_mnt_ns_cur, count = 0;



	fd_mnt_ns_cur = fcntl(self->fd_mnt_ns[MNT_NS_LAST_INDEX], F_DUPFD_CLOEXEC);

	ASSERT_GE(fd_mnt_ns_cur, 0);



	for (;; count++) {

		struct mnt_ns_info info = {};

		int fd_mnt_ns_prev;



		fd_mnt_ns_prev = ioctl(fd_mnt_ns_cur, NS_MNT_GET_PREV, &info);

		if (fd_mnt_ns_prev < 0 && errno == ENOENT)

			break;

		ASSERT_GE(fd_mnt_ns_prev, 0);

		ASSERT_EQ(close(fd_mnt_ns_cur), 0);

		fd_mnt_ns_cur = fd_mnt_ns_prev;

	}

	ASSERT_EQ(count, MNT_NS_LAST_INDEX);

}



TEST_F(iterate_mount_namespaces, iterate_forward)

{

	int fd_mnt_ns_cur;



	ASSERT_EQ(setns(self->fd_mnt_ns[0], CLONE_NEWNS), 0);



	fd_mnt_ns_cur = self->fd_mnt_ns[0];

	for (int i = 1; i < MNT_NS_COUNT; i++) {

		struct mnt_ns_info info = {};

		int fd_mnt_ns_next;



		fd_mnt_ns_next = ioctl(fd_mnt_ns_cur, NS_MNT_GET_NEXT, &info);

		ASSERT_GE(fd_mnt_ns_next, 0);

		ASSERT_EQ(close(fd_mnt_ns_cur), 0);

		fd_mnt_ns_cur = fd_mnt_ns_next;

		ASSERT_EQ(info.mnt_ns_id, self->mnt_ns_id[i]);

	}

}



TEST_F(iterate_mount_namespaces, iterate_backward)

{

	int fd_mnt_ns_cur;



	ASSERT_EQ(setns(self->fd_mnt_ns[MNT_NS_LAST_INDEX], CLONE_NEWNS), 0);



	fd_mnt_ns_cur = self->fd_mnt_ns[MNT_NS_LAST_INDEX];

	for (int i = MNT_NS_LAST_INDEX - 1; i >= 0; i--) {

		struct mnt_ns_info info = {};

		int fd_mnt_ns_prev;



		fd_mnt_ns_prev = ioctl(fd_mnt_ns_cur, NS_MNT_GET_PREV, &info);

		ASSERT_GE(fd_mnt_ns_prev, 0);

		ASSERT_EQ(close(fd_mnt_ns_cur), 0);

		fd_mnt_ns_cur = fd_mnt_ns_prev;

		ASSERT_EQ(info.mnt_ns_id, self->mnt_ns_id[i]);

	}

}



TEST_HARNESS_MAIN