Test that forward and backward iteration works correctly. Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> --- .../testing/selftests/filesystems/nsfs/.gitignore | 1 + tools/testing/selftests/filesystems/nsfs/Makefile | 2 +- .../selftests/filesystems/nsfs/iterate_mntns.c | 149 +++++++++++++++++++++ 3 files changed, 151 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/filesystems/nsfs/.gitignore b/tools/testing/selftests/filesystems/nsfs/.gitignore index ed79ebdf286e4d945cfbbf80fb072ba3e05c9112..92a8249006d1e0817800df0057183a94ef0f939d 100644 --- a/tools/testing/selftests/filesystems/nsfs/.gitignore +++ b/tools/testing/selftests/filesystems/nsfs/.gitignore @@ -1,3 +1,4 @@ # SPDX-License-Identifier: GPL-2.0-only owner pidns +iterate_mntns diff --git a/tools/testing/selftests/filesystems/nsfs/Makefile b/tools/testing/selftests/filesystems/nsfs/Makefile index c2f3ca6e488e9ddb49514e1b8e93909d5594259b..231aaa7dfd95c638c23e0a8e5a1d4f7f16f00f7b 100644 --- a/tools/testing/selftests/filesystems/nsfs/Makefile +++ b/tools/testing/selftests/filesystems/nsfs/Makefile @@ -1,5 +1,5 @@ # SPDX-License-Identifier: GPL-2.0-only -TEST_GEN_PROGS := owner pidns +TEST_GEN_PROGS := owner pidns iterate_mntns CFLAGS := -Wall -Werror diff --git a/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c b/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c new file mode 100644 index 0000000000000000000000000000000000000000..457cf76f3c5f368872292714b44c037968de4ad3 --- /dev/null +++ b/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c @@ -0,0 +1,149 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +// Copyright (c) 2024 Christian Brauner <brauner@xxxxxxxxxx> + +#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 -- 2.45.2