[LTP] [PATCH v3 04/11] Add listmount01 test

[Andrea Cervesato]

From: Andrea Cervesato <andrea.cervesato@suse.com>

This test verifies that listmount() is properly recognizing a mounted
root directory using LSMT_ROOT flag.
---
 runtest/syscalls                                  |  2 +
 testcases/kernel/syscalls/listmount/.gitignore    |  1 +
 testcases/kernel/syscalls/listmount/Makefile      |  7 +++
 testcases/kernel/syscalls/listmount/listmount.h   | 26 +++++++++
 testcases/kernel/syscalls/listmount/listmount01.c | 66 +++++++++++++++++++++++
 5 files changed, 102 insertions(+)

diff --git a/runtest/syscalls b/runtest/syscalls
index cf06ee563..bce04c0cf 100644
--- a/runtest/syscalls
+++ b/runtest/syscalls
@@ -706,6 +706,8 @@ linkat02 linkat02
 
 listen01 listen01
 
+listmount01 listmount01
+
 listxattr01 listxattr01
 listxattr02 listxattr02
 listxattr03 listxattr03
diff --git a/testcases/kernel/syscalls/listmount/.gitignore b/testcases/kernel/syscalls/listmount/.gitignore
new file mode 100644
index 000000000..5257b298c
--- /dev/null
+++ b/testcases/kernel/syscalls/listmount/.gitignore
@@ -0,0 +1 @@
+listmount01
diff --git a/testcases/kernel/syscalls/listmount/Makefile b/testcases/kernel/syscalls/listmount/Makefile
new file mode 100644
index 000000000..8cf1b9024
--- /dev/null
+++ b/testcases/kernel/syscalls/listmount/Makefile
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2024 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+
+top_srcdir		?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/listmount/listmount.h b/testcases/kernel/syscalls/listmount/listmount.h
new file mode 100644
index 000000000..93766cd33
--- /dev/null
+++ b/testcases/kernel/syscalls/listmount/listmount.h
@@ -0,0 +1,26 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2024 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+#ifndef LISTMOUNT_H
+
+#define _GNU_SOURCE
+
+#include "tst_test.h"
+#include "lapi/mount.h"
+#include "lapi/syscalls.h"
+
+static inline ssize_t listmount(uint64_t mnt_id, uint64_t last_mnt_id,
+			 uint64_t list[], size_t num, unsigned int flags)
+{
+	struct mnt_id_req req = {
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.mnt_id = mnt_id,
+		.param = last_mnt_id,
+	};
+
+	return tst_syscall(__NR_listmount, &req, list, num, flags);
+}
+
+#endif
diff --git a/testcases/kernel/syscalls/listmount/listmount01.c b/testcases/kernel/syscalls/listmount/listmount01.c
new file mode 100644
index 000000000..e586c3ab3
--- /dev/null
+++ b/testcases/kernel/syscalls/listmount/listmount01.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * This test verifies that listmount() is properly recognizing a mounted
+ * root directory using LSMT_ROOT flag.
+ *
+ * [Algorithm]
+ *
+ * * move into a new unshared namespace
+ * * mount() a root inside temporary folder and get its mount ID
+ * * get list of mounted IDs using listmount(LSMT_ROOT, ..)
+ * * verify that the root mount ID is the only mount ID present inside the list
+ */
+
+#include "listmount.h"
+#include "lapi/stat.h"
+#include "lapi/sched.h"
+
+#define MNTPOINT "mntpoint"
+#define LISTSIZE 32
+
+static uint64_t root_id;
+
+static void run(void)
+{
+	uint64_t list[LISTSIZE];
+
+	TST_EXP_POSITIVE(listmount(LSMT_ROOT, 0, list, LISTSIZE, 0));
+	if (TST_RET == -1)
+		return;
+
+	TST_EXP_EQ_LI(TST_RET, 1);
+	TST_EXP_EQ_LI(list[0], root_id);
+}
+
+static void setup(void)
+{
+	struct statx sx;
+
+	SAFE_UNSHARE(CLONE_NEWNS);
+
+	SAFE_CHROOT(MNTPOINT);
+	SAFE_MOUNT("", "/", NULL, MS_REC | MS_PRIVATE, NULL);
+	SAFE_STATX(AT_FDCWD, "/", 0, STATX_MNT_ID_UNIQUE, &sx);
+
+	root_id = sx.stx_mnt_id;
+}
+
+static struct tst_test test = {
+	.test_all = run,
+	.setup = setup,
+	.forks_child = 1,
+	.min_kver = "6.8",
+	.mount_device = 1,
+	.mntpoint = MNTPOINT,
+	.all_filesystems = 1,
+	.skip_filesystems = (const char *const []) {
+		"fuse",
+		NULL
+	},
+};

-- 
2.35.3