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

Source file repositories/reference/linux-study-clean/tools/testing/selftests/filesystems/nsfs/iterate_mntns.c

File Facts

System
Linux kernel
Corpus path
tools/testing/selftests/filesystems/nsfs/iterate_mntns.c
Extension
.c
Size
4220 bytes
Lines
169
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: implementation source
Status
source implementation candidate

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

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];
};

static inline bool mntns_in_list(__u64 *mnt_ns_id, struct mnt_ns_info *info)
{
	for (int i = 0; i < MNT_NS_COUNT; i++) {
		if (mnt_ns_id[i] == info->mnt_ns_id)
			return true;
	}
	return false;
}

FIXTURE_SETUP(iterate_mount_namespaces)
{
	for (int i = 0; i < MNT_NS_COUNT; i++)
		self->fd_mnt_ns[i] = -EBADF;

	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 (;;) {
		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;
		if (mntns_in_list(self->mnt_ns_id, &info))
			count++;
		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 (;;) {
		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)

Annotation

Implementation Notes