Add listmount04 test

Verify that listmount() raises the correct errors according with
invalid data:

- EFAULT: req or mnt_id are unaccessible memories
- EINVAL: invalid flags or mnt_id request
- ENOENT: non-existent mount point

Reviewed-by: Cyril Hrubis <[email protected]>
Signed-off-by: Andrea Cervesato <[email protected]>

runtest/syscalls

@@ -734,6 +734,7 @@ listen01 listen01
 listmount01 listmount01
 listmount02 listmount02
 listmount03 listmount03
+listmount04 listmount04
 
 listxattr01 listxattr01
 listxattr02 listxattr02

testcases/kernel/syscalls/listmount/.gitignore

@@ -1,3 +1,4 @@
 listmount01
 listmount02
 listmount03
+listmount04

testcases/kernel/syscalls/listmount/listmount04.c

@@ -0,0 +1,143 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 SUSE LLC Andrea Cervesato <[email protected]>
+ */
+
+/*\
+ * [Description]
+ *
+ * Verify that listmount() raises the correct errors according with
+ * invalid data:
+ *
+ * - EFAULT: req or mnt_id are unaccessible memories
+ * - EINVAL: invalid flags or mnt_id request
+ * - ENOENT: non-existent mount point
+ */
+
+#define _GNU_SOURCE
+
+#include "tst_test.h"
+#include "lapi/mount.h"
+#include "lapi/syscalls.h"
+
+#define MNT_SIZE 32
+
+static struct mnt_id_req *request;
+static uint64_t mnt_ids[MNT_SIZE];
+
+static struct tcase {
+	int req_usage;
+	uint32_t size;
+	uint32_t spare;
+	uint64_t mnt_id;
+	uint64_t param;
+	uint64_t *mnt_ids;
+	size_t nr_mnt_ids;
+	uint64_t flags;
+	int exp_errno;
+	char *msg;
+} tcases[] = {
+	{
+		.req_usage = 0,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = EFAULT,
+		.msg = "request points to unaccessible memory",
+	},
+	{
+		.req_usage = 1,
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.mnt_id = LSMT_ROOT,
+		.mnt_ids = NULL,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = EFAULT,
+		.msg = "mnt_ids points to unaccessible memory",
+	},
+	{
+		.req_usage = 1,
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.mnt_id = LSMT_ROOT,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.flags = -1,
+		.exp_errno = EINVAL,
+		.msg = "invalid flags",
+	},
+	{
+		.req_usage = 1,
+		.size = 0,
+		.mnt_id = LSMT_ROOT,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = EINVAL,
+		.msg = "insufficient mnt_id_req.size",
+	},
+	{
+		.req_usage = 1,
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.spare = -1,
+		.mnt_id = LSMT_ROOT,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = EINVAL,
+		.msg = "invalid mnt_id_req.spare",
+	},
+	{
+		.req_usage = 1,
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.mnt_id = LSMT_ROOT,
+		.param = STATMOUNT_PROPAGATE_FROM + 1,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = EINVAL,
+		.msg = "invalid mnt_id_req.param",
+	},
+	{
+		.req_usage = 1,
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.mnt_id = 0,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = EINVAL,
+		.msg = "invalid mnt_id_req.mnt_id",
+	},
+	{
+		.req_usage = 1,
+		.size = MNT_ID_REQ_SIZE_VER0,
+		.mnt_id = LSMT_ROOT - 1,
+		.mnt_ids = mnt_ids,
+		.nr_mnt_ids = MNT_SIZE,
+		.exp_errno = ENOENT,
+		.msg = "non-existant mnt_id",
+	},
+};
+
+static void run(unsigned int n)
+{
+	struct tcase *tc = &tcases[n];
+	struct mnt_id_req *req = NULL;
+
+	memset(mnt_ids, 0, sizeof(mnt_ids));
+
+	if (tc->req_usage) {
+		req = request;
+		req->mnt_id = tc->mnt_id;
+		req->param = tc->param;
+		req->size = tc->size;
+		req->spare = tc->spare;
+	}
+
+	TST_EXP_FAIL(tst_syscall(__NR_listmount, req, tc->mnt_ids,
+		tc->nr_mnt_ids, tc->flags), tc->exp_errno,
+		"%s", tc->msg);
+}
+
+static struct tst_test test = {
+	.test = run,
+	.tcnt = ARRAY_SIZE(tcases),
+	.min_kver = "6.8",
+	.bufs = (struct tst_buffers []) {
+		{ &request, .size = sizeof(struct mnt_id_req) },
+		{},
+	},
+};