Message-Id: <20250910-work-namespace-v1-31-4dd56e7359d8@kernel.org>
Date: Wed, 10 Sep 2025 16:37:16 +0200
From: Christian Brauner <brauner@...nel.org>
To: Jan Kara <jack@...e.cz>, Amir Goldstein <amir73il@...il.com>, 
 linux-fsdevel@...r.kernel.org
Cc: Josef Bacik <josef@...icpanda.com>, Jeff Layton <jlayton@...nel.org>, 
 Mike Yuan <me@...dnzj.com>, 
 Zbigniew Jędrzejewski-Szmek <zbyszek@...waw.pl>, 
 Lennart Poettering <mzxreary@...inter.de>, 
 Daan De Meyer <daan.j.demeyer@...il.com>, Aleksa Sarai <cyphar@...har.com>, 
 Alexander Viro <viro@...iv.linux.org.uk>, Jens Axboe <axboe@...nel.dk>, 
 Tejun Heo <tj@...nel.org>, Johannes Weiner <hannes@...xchg.org>, 
 Michal Koutný <mkoutny@...e.com>, 
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, 
 Paolo Abeni <pabeni@...hat.com>, Simon Horman <horms@...nel.org>, 
 Chuck Lever <chuck.lever@...cle.com>, linux-nfs@...r.kernel.org, 
 linux-kselftest@...r.kernel.org, linux-block@...r.kernel.org, 
 linux-kernel@...r.kernel.org, cgroups@...r.kernel.org, 
 netdev@...r.kernel.org, Christian Brauner <brauner@...nel.org>
Subject: [PATCH 31/32] selftests/namespaces: add identifier selftests

Add a bunch of selftests for the identifier retrieval ioctls.

Signed-off-by: Christian Brauner <brauner@...nel.org>
---
 tools/testing/selftests/namespaces/.gitignore  |   1 +
 tools/testing/selftests/namespaces/Makefile    |   7 +
 tools/testing/selftests/namespaces/config      |   7 +
 tools/testing/selftests/namespaces/nsid_test.c | 986 +++++++++++++++++++++++++
 4 files changed, 1001 insertions(+)

diff --git a/tools/testing/selftests/namespaces/.gitignore b/tools/testing/selftests/namespaces/.gitignore
new file mode 100644
index 000000000000..c1e8d634dd21
--- /dev/null
+++ b/tools/testing/selftests/namespaces/.gitignore
@@ -0,0 +1 @@
+nsid_test
diff --git a/tools/testing/selftests/namespaces/Makefile b/tools/testing/selftests/namespaces/Makefile
new file mode 100644
index 000000000000..9280c703533e
--- /dev/null
+++ b/tools/testing/selftests/namespaces/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-only
+CFLAGS += -Wall -O0 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
+
+TEST_GEN_PROGS := nsid_test
+
+include ../lib.mk
+
diff --git a/tools/testing/selftests/namespaces/config b/tools/testing/selftests/namespaces/config
new file mode 100644
index 000000000000..d09836260262
--- /dev/null
+++ b/tools/testing/selftests/namespaces/config
@@ -0,0 +1,7 @@
+CONFIG_UTS_NS=y
+CONFIG_TIME_NS=y
+CONFIG_IPC_NS=y
+CONFIG_USER_NS=y
+CONFIG_PID_NS=y
+CONFIG_NET_NS=y
+CONFIG_CGROUPS=y
diff --git a/tools/testing/selftests/namespaces/nsid_test.c b/tools/testing/selftests/namespaces/nsid_test.c
new file mode 100644
index 000000000000..280dde9b71dc
--- /dev/null
+++ b/tools/testing/selftests/namespaces/nsid_test.c
@@ -0,0 +1,986 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <assert.h>
+#include <fcntl.h>
+#include <inttypes.h>
+#include <libgen.h>
+#include <limits.h>
+#include <pthread.h>
+#include <string.h>
+#include <sys/mount.h>
+#include <poll.h>
+#include <sys/epoll.h>
+#include <sys/resource.h>
+#include <sys/stat.h>
+#include <sys/socket.h>
+#include <sys/un.h>
+#include <unistd.h>
+#include <linux/fs.h>
+#include <linux/limits.h>
+#include <linux/nsfs.h>
+#include "../kselftest_harness.h"
+
+TEST(nsid_mntns_basic)
+{
+	__u64 mnt_ns_id = 0;
+	int fd_mntns;
+	int ret;
+
+	/* Open the current mount namespace */
+	fd_mntns = open("/proc/self/ns/mnt", O_RDONLY);
+	ASSERT_GE(fd_mntns, 0);
+
+	/* Get the mount namespace ID */
+	ret = ioctl(fd_mntns, NS_GET_MNTNS_ID, &mnt_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(mnt_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 mnt_ns_id2 = 0;
+	ret = ioctl(fd_mntns, NS_GET_MNTNS_ID, &mnt_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(mnt_ns_id, mnt_ns_id2);
+
+	close(fd_mntns);
+}
+
+TEST(nsid_mntns_separate)
+{
+	__u64 parent_mnt_ns_id = 0;
+	__u64 child_mnt_ns_id = 0;
+	int fd_parent_mntns, fd_child_mntns;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's mount namespace ID */
+	fd_parent_mntns = open("/proc/self/ns/mnt", O_RDONLY);
+	ASSERT_GE(fd_parent_mntns, 0);
+	ret = ioctl(fd_parent_mntns, NS_GET_MNTNS_ID, &parent_mnt_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_mnt_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new mount namespace */
+		ret = unshare(CLONE_NEWNS);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Signal success */
+		write(pipefd[1], "Y", 1);
+		close(pipefd[1]);
+
+		/* Keep namespace alive */
+		pause();
+		_exit(0);
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+	close(pipefd[0]);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_mntns);
+		SKIP(return, "No permission to create mount namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	/* Open child's mount namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/mnt", pid);
+	fd_child_mntns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_mntns, 0);
+
+	/* Get child's mount namespace ID */
+	ret = ioctl(fd_child_mntns, NS_GET_MNTNS_ID, &child_mnt_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_mnt_ns_id, 0);
+
+	/* Parent and child should have different mount namespace IDs */
+	ASSERT_NE(parent_mnt_ns_id, child_mnt_ns_id);
+
+	close(fd_parent_mntns);
+	close(fd_child_mntns);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_cgroupns_basic)
+{
+	__u64 cgroup_ns_id = 0;
+	int fd_cgroupns;
+	int ret;
+
+	/* Open the current cgroup namespace */
+	fd_cgroupns = open("/proc/self/ns/cgroup", O_RDONLY);
+	ASSERT_GE(fd_cgroupns, 0);
+
+	/* Get the cgroup namespace ID */
+	ret = ioctl(fd_cgroupns, NS_GET_CGROUPNS_ID, &cgroup_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(cgroup_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 cgroup_ns_id2 = 0;
+	ret = ioctl(fd_cgroupns, NS_GET_CGROUPNS_ID, &cgroup_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(cgroup_ns_id, cgroup_ns_id2);
+
+	close(fd_cgroupns);
+}
+
+TEST(nsid_cgroupns_separate)
+{
+	__u64 parent_cgroup_ns_id = 0;
+	__u64 child_cgroup_ns_id = 0;
+	int fd_parent_cgroupns, fd_child_cgroupns;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's cgroup namespace ID */
+	fd_parent_cgroupns = open("/proc/self/ns/cgroup", O_RDONLY);
+	ASSERT_GE(fd_parent_cgroupns, 0);
+	ret = ioctl(fd_parent_cgroupns, NS_GET_CGROUPNS_ID, &parent_cgroup_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_cgroup_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new cgroup namespace */
+		ret = unshare(CLONE_NEWCGROUP);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Signal success */
+		write(pipefd[1], "Y", 1);
+		close(pipefd[1]);
+
+		/* Keep namespace alive */
+		pause();
+		_exit(0);
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+	close(pipefd[0]);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_cgroupns);
+		SKIP(return, "No permission to create cgroup namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	/* Open child's cgroup namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/cgroup", pid);
+	fd_child_cgroupns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_cgroupns, 0);
+
+	/* Get child's cgroup namespace ID */
+	ret = ioctl(fd_child_cgroupns, NS_GET_CGROUPNS_ID, &child_cgroup_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_cgroup_ns_id, 0);
+
+	/* Parent and child should have different cgroup namespace IDs */
+	ASSERT_NE(parent_cgroup_ns_id, child_cgroup_ns_id);
+
+	close(fd_parent_cgroupns);
+	close(fd_child_cgroupns);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_ipcns_basic)
+{
+	__u64 ipc_ns_id = 0;
+	int fd_ipcns;
+	int ret;
+
+	/* Open the current IPC namespace */
+	fd_ipcns = open("/proc/self/ns/ipc", O_RDONLY);
+	ASSERT_GE(fd_ipcns, 0);
+
+	/* Get the IPC namespace ID */
+	ret = ioctl(fd_ipcns, NS_GET_IPCNS_ID, &ipc_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(ipc_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 ipc_ns_id2 = 0;
+	ret = ioctl(fd_ipcns, NS_GET_IPCNS_ID, &ipc_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(ipc_ns_id, ipc_ns_id2);
+
+	close(fd_ipcns);
+}
+
+TEST(nsid_ipcns_separate)
+{
+	__u64 parent_ipc_ns_id = 0;
+	__u64 child_ipc_ns_id = 0;
+	int fd_parent_ipcns, fd_child_ipcns;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's IPC namespace ID */
+	fd_parent_ipcns = open("/proc/self/ns/ipc", O_RDONLY);
+	ASSERT_GE(fd_parent_ipcns, 0);
+	ret = ioctl(fd_parent_ipcns, NS_GET_IPCNS_ID, &parent_ipc_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_ipc_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new IPC namespace */
+		ret = unshare(CLONE_NEWIPC);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Signal success */
+		write(pipefd[1], "Y", 1);
+		close(pipefd[1]);
+
+		/* Keep namespace alive */
+		pause();
+		_exit(0);
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+	close(pipefd[0]);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_ipcns);
+		SKIP(return, "No permission to create IPC namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	/* Open child's IPC namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/ipc", pid);
+	fd_child_ipcns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_ipcns, 0);
+
+	/* Get child's IPC namespace ID */
+	ret = ioctl(fd_child_ipcns, NS_GET_IPCNS_ID, &child_ipc_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_ipc_ns_id, 0);
+
+	/* Parent and child should have different IPC namespace IDs */
+	ASSERT_NE(parent_ipc_ns_id, child_ipc_ns_id);
+
+	close(fd_parent_ipcns);
+	close(fd_child_ipcns);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_utsns_basic)
+{
+	__u64 uts_ns_id = 0;
+	int fd_utsns;
+	int ret;
+
+	/* Open the current UTS namespace */
+	fd_utsns = open("/proc/self/ns/uts", O_RDONLY);
+	ASSERT_GE(fd_utsns, 0);
+
+	/* Get the UTS namespace ID */
+	ret = ioctl(fd_utsns, NS_GET_UTSNS_ID, &uts_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(uts_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 uts_ns_id2 = 0;
+	ret = ioctl(fd_utsns, NS_GET_UTSNS_ID, &uts_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(uts_ns_id, uts_ns_id2);
+
+	close(fd_utsns);
+}
+
+TEST(nsid_utsns_separate)
+{
+	__u64 parent_uts_ns_id = 0;
+	__u64 child_uts_ns_id = 0;
+	int fd_parent_utsns, fd_child_utsns;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's UTS namespace ID */
+	fd_parent_utsns = open("/proc/self/ns/uts", O_RDONLY);
+	ASSERT_GE(fd_parent_utsns, 0);
+	ret = ioctl(fd_parent_utsns, NS_GET_UTSNS_ID, &parent_uts_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_uts_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new UTS namespace */
+		ret = unshare(CLONE_NEWUTS);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Signal success */
+		write(pipefd[1], "Y", 1);
+		close(pipefd[1]);
+
+		/* Keep namespace alive */
+		pause();
+		_exit(0);
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+	close(pipefd[0]);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_utsns);
+		SKIP(return, "No permission to create UTS namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	/* Open child's UTS namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/uts", pid);
+	fd_child_utsns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_utsns, 0);
+
+	/* Get child's UTS namespace ID */
+	ret = ioctl(fd_child_utsns, NS_GET_UTSNS_ID, &child_uts_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_uts_ns_id, 0);
+
+	/* Parent and child should have different UTS namespace IDs */
+	ASSERT_NE(parent_uts_ns_id, child_uts_ns_id);
+
+	close(fd_parent_utsns);
+	close(fd_child_utsns);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_userns_basic)
+{
+	__u64 user_ns_id = 0;
+	int fd_userns;
+	int ret;
+
+	/* Open the current user namespace */
+	fd_userns = open("/proc/self/ns/user", O_RDONLY);
+	ASSERT_GE(fd_userns, 0);
+
+	/* Get the user namespace ID */
+	ret = ioctl(fd_userns, NS_GET_USERNS_ID, &user_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(user_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 user_ns_id2 = 0;
+	ret = ioctl(fd_userns, NS_GET_USERNS_ID, &user_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(user_ns_id, user_ns_id2);
+
+	close(fd_userns);
+}
+
+TEST(nsid_userns_separate)
+{
+	__u64 parent_user_ns_id = 0;
+	__u64 child_user_ns_id = 0;
+	int fd_parent_userns, fd_child_userns;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's user namespace ID */
+	fd_parent_userns = open("/proc/self/ns/user", O_RDONLY);
+	ASSERT_GE(fd_parent_userns, 0);
+	ret = ioctl(fd_parent_userns, NS_GET_USERNS_ID, &parent_user_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_user_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new user namespace */
+		ret = unshare(CLONE_NEWUSER);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Signal success */
+		write(pipefd[1], "Y", 1);
+		close(pipefd[1]);
+
+		/* Keep namespace alive */
+		pause();
+		_exit(0);
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+	close(pipefd[0]);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_userns);
+		SKIP(return, "No permission to create user namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	/* Open child's user namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/user", pid);
+	fd_child_userns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_userns, 0);
+
+	/* Get child's user namespace ID */
+	ret = ioctl(fd_child_userns, NS_GET_USERNS_ID, &child_user_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_user_ns_id, 0);
+
+	/* Parent and child should have different user namespace IDs */
+	ASSERT_NE(parent_user_ns_id, child_user_ns_id);
+
+	close(fd_parent_userns);
+	close(fd_child_userns);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_timens_basic)
+{
+	__u64 time_ns_id = 0;
+	int fd_timens;
+	int ret;
+
+	/* Open the current time namespace */
+	fd_timens = open("/proc/self/ns/time", O_RDONLY);
+	if (fd_timens < 0) {
+		SKIP(return, "Time namespaces not supported");
+	}
+
+	/* Get the time namespace ID */
+	ret = ioctl(fd_timens, NS_GET_TIMENS_ID, &time_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(time_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 time_ns_id2 = 0;
+	ret = ioctl(fd_timens, NS_GET_TIMENS_ID, &time_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(time_ns_id, time_ns_id2);
+
+	close(fd_timens);
+}
+
+TEST(nsid_timens_separate)
+{
+	__u64 parent_time_ns_id = 0;
+	__u64 child_time_ns_id = 0;
+	int fd_parent_timens, fd_child_timens;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Open the current time namespace */
+	fd_parent_timens = open("/proc/self/ns/time", O_RDONLY);
+	if (fd_parent_timens < 0) {
+		SKIP(return, "Time namespaces not supported");
+	}
+
+	/* Get parent's time namespace ID */
+	ret = ioctl(fd_parent_timens, NS_GET_TIMENS_ID, &parent_time_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_time_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new time namespace */
+		ret = unshare(CLONE_NEWTIME);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES || errno == EINVAL) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Fork a grandchild to actually enter the new namespace */
+		pid_t grandchild = fork();
+		if (grandchild == 0) {
+			/* Grandchild is in the new namespace */
+			write(pipefd[1], "Y", 1);
+			close(pipefd[1]);
+			pause();
+			_exit(0);
+		} else if (grandchild > 0) {
+			/* Child writes grandchild PID and waits */
+			write(pipefd[1], "Y", 1);
+			write(pipefd[1], &grandchild, sizeof(grandchild));
+			close(pipefd[1]);
+			pause(); /* Keep the parent alive to maintain the grandchild */
+			_exit(0);
+		} else {
+			_exit(1);
+		}
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_timens);
+		close(pipefd[0]);
+		SKIP(return, "Cannot create time namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	pid_t grandchild_pid;
+	ASSERT_EQ(read(pipefd[0], &grandchild_pid, sizeof(grandchild_pid)), sizeof(grandchild_pid));
+	close(pipefd[0]);
+
+	/* Open grandchild's time namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/time", grandchild_pid);
+	fd_child_timens = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_timens, 0);
+
+	/* Get child's time namespace ID */
+	ret = ioctl(fd_child_timens, NS_GET_TIMENS_ID, &child_time_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_time_ns_id, 0);
+
+	/* Parent and child should have different time namespace IDs */
+	ASSERT_NE(parent_time_ns_id, child_time_ns_id);
+
+	close(fd_parent_timens);
+	close(fd_child_timens);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_pidns_basic)
+{
+	__u64 pid_ns_id = 0;
+	int fd_pidns;
+	int ret;
+
+	/* Open the current PID namespace */
+	fd_pidns = open("/proc/self/ns/pid", O_RDONLY);
+	ASSERT_GE(fd_pidns, 0);
+
+	/* Get the PID namespace ID */
+	ret = ioctl(fd_pidns, NS_GET_PIDNS_ID, &pid_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(pid_ns_id, 0);
+
+	/* Verify we can get the same ID again */
+	__u64 pid_ns_id2 = 0;
+	ret = ioctl(fd_pidns, NS_GET_PIDNS_ID, &pid_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(pid_ns_id, pid_ns_id2);
+
+	close(fd_pidns);
+}
+
+TEST(nsid_pidns_separate)
+{
+	__u64 parent_pid_ns_id = 0;
+	__u64 child_pid_ns_id = 0;
+	int fd_parent_pidns, fd_child_pidns;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's PID namespace ID */
+	fd_parent_pidns = open("/proc/self/ns/pid", O_RDONLY);
+	ASSERT_GE(fd_parent_pidns, 0);
+	ret = ioctl(fd_parent_pidns, NS_GET_PIDNS_ID, &parent_pid_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_pid_ns_id, 0);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new PID namespace */
+		ret = unshare(CLONE_NEWPID);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Fork a grandchild to actually enter the new namespace */
+		pid_t grandchild = fork();
+		if (grandchild == 0) {
+			/* Grandchild is in the new namespace */
+			write(pipefd[1], "Y", 1);
+			close(pipefd[1]);
+			pause();
+			_exit(0);
+		} else if (grandchild > 0) {
+			/* Child writes grandchild PID and waits */
+			write(pipefd[1], "Y", 1);
+			write(pipefd[1], &grandchild, sizeof(grandchild));
+			close(pipefd[1]);
+			pause(); /* Keep the parent alive to maintain the grandchild */
+			_exit(0);
+		} else {
+			_exit(1);
+		}
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_pidns);
+		close(pipefd[0]);
+		SKIP(return, "No permission to create PID namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	pid_t grandchild_pid;
+	ASSERT_EQ(read(pipefd[0], &grandchild_pid, sizeof(grandchild_pid)), sizeof(grandchild_pid));
+	close(pipefd[0]);
+
+	/* Open grandchild's PID namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/pid", grandchild_pid);
+	fd_child_pidns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_pidns, 0);
+
+	/* Get child's PID namespace ID */
+	ret = ioctl(fd_child_pidns, NS_GET_PIDNS_ID, &child_pid_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_pid_ns_id, 0);
+
+	/* Parent and child should have different PID namespace IDs */
+	ASSERT_NE(parent_pid_ns_id, child_pid_ns_id);
+
+	close(fd_parent_pidns);
+	close(fd_child_pidns);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST(nsid_netns_basic)
+{
+	__u64 net_ns_id = 0;
+	__u64 netns_cookie = 0;
+	int fd_netns;
+	int sock;
+	socklen_t optlen;
+	int ret;
+
+	/* Open the current network namespace */
+	fd_netns = open("/proc/self/ns/net", O_RDONLY);
+	ASSERT_GE(fd_netns, 0);
+
+	/* Get the network namespace ID via ioctl */
+	ret = ioctl(fd_netns, NS_GET_NETNS_ID, &net_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(net_ns_id, 0);
+
+	/* Create a socket to get the SO_NETNS_COOKIE */
+	sock = socket(AF_UNIX, SOCK_STREAM, 0);
+	ASSERT_GE(sock, 0);
+
+	/* Get the network namespace cookie via socket option */
+	optlen = sizeof(netns_cookie);
+	ret = getsockopt(sock, SOL_SOCKET, SO_NETNS_COOKIE, &netns_cookie, &optlen);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(optlen, sizeof(netns_cookie));
+
+	/* The namespace ID and cookie should be identical */
+	ASSERT_EQ(net_ns_id, netns_cookie);
+
+	/* Verify we can get the same ID again */
+	__u64 net_ns_id2 = 0;
+	ret = ioctl(fd_netns, NS_GET_NETNS_ID, &net_ns_id2);
+	ASSERT_EQ(ret, 0);
+	ASSERT_EQ(net_ns_id, net_ns_id2);
+
+	close(sock);
+	close(fd_netns);
+}
+
+TEST(nsid_netns_separate)
+{
+	__u64 parent_net_ns_id = 0;
+	__u64 parent_netns_cookie = 0;
+	__u64 child_net_ns_id = 0;
+	__u64 child_netns_cookie = 0;
+	int fd_parent_netns, fd_child_netns;
+	int parent_sock, child_sock;
+	socklen_t optlen;
+	int ret;
+	pid_t pid;
+	int pipefd[2];
+
+	/* Get parent's network namespace ID */
+	fd_parent_netns = open("/proc/self/ns/net", O_RDONLY);
+	ASSERT_GE(fd_parent_netns, 0);
+	ret = ioctl(fd_parent_netns, NS_GET_NETNS_ID, &parent_net_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(parent_net_ns_id, 0);
+
+	/* Get parent's network namespace cookie */
+	parent_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+	ASSERT_GE(parent_sock, 0);
+	optlen = sizeof(parent_netns_cookie);
+	ret = getsockopt(parent_sock, SOL_SOCKET, SO_NETNS_COOKIE, &parent_netns_cookie, &optlen);
+	ASSERT_EQ(ret, 0);
+
+	/* Verify parent's ID and cookie match */
+	ASSERT_EQ(parent_net_ns_id, parent_netns_cookie);
+
+	/* Create a pipe for synchronization */
+	ASSERT_EQ(pipe(pipefd), 0);
+
+	pid = fork();
+	ASSERT_GE(pid, 0);
+
+	if (pid == 0) {
+		/* Child process */
+		close(pipefd[0]);
+
+		/* Create new network namespace */
+		ret = unshare(CLONE_NEWNET);
+		if (ret != 0) {
+			/* Skip test if we don't have permission */
+			if (errno == EPERM || errno == EACCES) {
+				write(pipefd[1], "S", 1); /* Signal skip */
+				_exit(0);
+			}
+			_exit(1);
+		}
+
+		/* Signal success */
+		write(pipefd[1], "Y", 1);
+		close(pipefd[1]);
+
+		/* Keep namespace alive */
+		pause();
+		_exit(0);
+	}
+
+	/* Parent process */
+	close(pipefd[1]);
+
+	char buf;
+	ASSERT_EQ(read(pipefd[0], &buf, 1), 1);
+	close(pipefd[0]);
+
+	if (buf == 'S') {
+		/* Child couldn't create namespace, skip test */
+		kill(pid, SIGTERM);
+		waitpid(pid, NULL, 0);
+		close(fd_parent_netns);
+		close(parent_sock);
+		SKIP(return, "No permission to create network namespace");
+	}
+
+	ASSERT_EQ(buf, 'Y');
+
+	/* Open child's network namespace */
+	char path[256];
+	snprintf(path, sizeof(path), "/proc/%d/ns/net", pid);
+	fd_child_netns = open(path, O_RDONLY);
+	ASSERT_GE(fd_child_netns, 0);
+
+	/* Get child's network namespace ID */
+	ret = ioctl(fd_child_netns, NS_GET_NETNS_ID, &child_net_ns_id);
+	ASSERT_EQ(ret, 0);
+	ASSERT_NE(child_net_ns_id, 0);
+
+	/* Create socket in child's namespace to get cookie */
+	ret = setns(fd_child_netns, CLONE_NEWNET);
+	if (ret == 0) {
+		child_sock = socket(AF_UNIX, SOCK_STREAM, 0);
+		ASSERT_GE(child_sock, 0);
+
+		optlen = sizeof(child_netns_cookie);
+		ret = getsockopt(child_sock, SOL_SOCKET, SO_NETNS_COOKIE, &child_netns_cookie, &optlen);
+		ASSERT_EQ(ret, 0);
+
+		/* Verify child's ID and cookie match */
+		ASSERT_EQ(child_net_ns_id, child_netns_cookie);
+
+		close(child_sock);
+
+		/* Return to parent namespace */
+		setns(fd_parent_netns, CLONE_NEWNET);
+	}
+
+	/* Parent and child should have different network namespace IDs */
+	ASSERT_NE(parent_net_ns_id, child_net_ns_id);
+	if (child_netns_cookie != 0) {
+		ASSERT_NE(parent_netns_cookie, child_netns_cookie);
+	}
+
+	close(fd_parent_netns);
+	close(fd_child_netns);
+	close(parent_sock);
+
+	/* Clean up child process */
+	kill(pid, SIGTERM);
+	waitpid(pid, NULL, 0);
+}
+
+TEST_HARNESS_MAIN

-- 
2.47.3

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