selftests/namespaces: verify initial namespace inode numbers

Make sure that all works correctly.

Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/tools/testing/selftests/namespaces/.gitignore b/tools/testing/selftests/namespaces/.gitignore
index 7639dbf58bbf873b39a3fd74fd8f7b6d9c92b020..ccfb40837a7333feb6717381f34759261a3c61ad 100644 (file)
--- a/tools/testing/selftests/namespaces/.gitignore
+++ b/tools/testing/selftests/namespaces/.gitignore
@@ -1,2 +1,3 @@
 nsid_test
 file_handle_test
+init_ino_test

diff --git a/tools/testing/selftests/namespaces/Makefile b/tools/testing/selftests/namespaces/Makefile
index f6c117ce2c2b8095c1660e0ab2317736871414dd..5fe4b3dc07d3edfa0bdacdc4378a04f0559be9f8 100644 (file)
--- a/tools/testing/selftests/namespaces/Makefile
+++ b/tools/testing/selftests/namespaces/Makefile
@@ -1,7 +1,7 @@
 # SPDX-License-Identifier: GPL-2.0-only
 CFLAGS += -Wall -O0 -g $(KHDR_INCLUDES) $(TOOLS_INCLUDES)
 
-TEST_GEN_PROGS := nsid_test file_handle_test
+TEST_GEN_PROGS := nsid_test file_handle_test init_ino_test
 
 include ../lib.mk
 

diff --git a/tools/testing/selftests/namespaces/init_ino_test.c b/tools/testing/selftests/namespaces/init_ino_test.c
new file mode 100644 (file)
index 0000000..5b6993c
--- /dev/null
+++ b/tools/testing/selftests/namespaces/init_ino_test.c
@@ -0,0 +1,61 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+// Copyright (c) 2025 Christian Brauner <brauner@kernel.org>
+
+#define _GNU_SOURCE
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include <linux/nsfs.h>
+
+#include "../kselftest_harness.h"
+
+struct ns_info {
+       const char *name;
+       const char *proc_path;
+       unsigned int expected_ino;
+};
+
+static struct ns_info namespaces[] = {
+       { "ipc", "/proc/1/ns/ipc", IPC_NS_INIT_INO },
+       { "uts", "/proc/1/ns/uts", UTS_NS_INIT_INO },
+       { "user", "/proc/1/ns/user", USER_NS_INIT_INO },
+       { "pid", "/proc/1/ns/pid", PID_NS_INIT_INO },
+       { "cgroup", "/proc/1/ns/cgroup", CGROUP_NS_INIT_INO },
+       { "time", "/proc/1/ns/time", TIME_NS_INIT_INO },
+       { "net", "/proc/1/ns/net", NET_NS_INIT_INO },
+       { "mnt", "/proc/1/ns/mnt", MNT_NS_INIT_INO },
+};
+
+TEST(init_namespace_inodes)
+{
+       struct stat st;
+
+       for (int i = 0; i < sizeof(namespaces) / sizeof(namespaces[0]); i++) {
+               int ret = stat(namespaces[i].proc_path, &st);
+
+               /* Some namespaces might not be available (e.g., time namespace on older kernels) */
+               if (ret < 0) {
+                       if (errno == ENOENT) {
+                               ksft_test_result_skip("%s namespace not available\n",
+                                                     namespaces[i].name);
+                               continue;
+                       }
+                       ASSERT_GE(ret, 0)
+                       TH_LOG("Failed to stat %s: %s",
+                              namespaces[i].proc_path, strerror(errno));
+               }
+
+               ASSERT_EQ(st.st_ino, namespaces[i].expected_ino)
+                       TH_LOG("Namespace %s has inode 0x%lx, expected 0x%x",
+                              namespaces[i].name, st.st_ino, namespaces[i].expected_ino);
+
+               ksft_print_msg("Namespace %s: inode 0x%lx matches expected 0x%x\n",
+                              namespaces[i].name, st.st_ino, namespaces[i].expected_ino);
+       }
+}
+
+TEST_HARNESS_MAIN