[LTP] [PATCH 7/8] Add setxattrat01 test

[Andrea Cervesato]

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

Test if setxattrat() syscall is correctly following symlink, setting
a xattr on a file.

Signed-off-by: Andrea Cervesato <andrea.cervesato@suse.com>
---
 testcases/kernel/syscalls/setxattrat/.gitignore    |   1 +
 testcases/kernel/syscalls/setxattrat/Makefile      |   8 ++
 .../kernel/syscalls/setxattrat/setxattrat01.c      | 151 +++++++++++++++++++++
 3 files changed, 160 insertions(+)

diff --git a/testcases/kernel/syscalls/setxattrat/.gitignore b/testcases/kernel/syscalls/setxattrat/.gitignore
new file mode 100644
index 0000000000000000000000000000000000000000..e636401d7ac3ed58c5f9a24ad31291f0dc1c9ae7
--- /dev/null
+++ b/testcases/kernel/syscalls/setxattrat/.gitignore
@@ -0,0 +1 @@
+setxattrat01
diff --git a/testcases/kernel/syscalls/setxattrat/Makefile b/testcases/kernel/syscalls/setxattrat/Makefile
new file mode 100644
index 0000000000000000000000000000000000000000..e582f727dd8719bf51685070d1e4a4c5f5fac61f
--- /dev/null
+++ b/testcases/kernel/syscalls/setxattrat/Makefile
@@ -0,0 +1,8 @@
+# SPDX-License-Identifier: GPL-2.0-or-later
+# Copyright (C) 2025 SUSE LLC
+
+top_srcdir		?= ../../../..
+
+include $(top_srcdir)/include/mk/testcases.mk
+
+include $(top_srcdir)/include/mk/generic_leaf_target.mk
diff --git a/testcases/kernel/syscalls/setxattrat/setxattrat01.c b/testcases/kernel/syscalls/setxattrat/setxattrat01.c
new file mode 100644
index 0000000000000000000000000000000000000000..ef0ab2b1137e800b2edee85bd42bdf6d34fe0adc
--- /dev/null
+++ b/testcases/kernel/syscalls/setxattrat/setxattrat01.c
@@ -0,0 +1,151 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2025 SUSE LLC Andrea Cervesato <andrea.cervesato@suse.com>
+ */
+
+/*\
+ * [Description]
+ *
+ * Test if setxattrat() syscall is correctly following symlink, setting a
+ * xattr on a file.
+ *
+ * [Algorithm]
+ *
+ * - create a file and the symlink pointing to it
+ * - run setxattrat() on the symlink following the pointing file
+ * - verify that file xattr has been set
+ * - verify that symlink xattr has not been set
+ * - run setxattrat() on the symlink with AT_SYMLINK_NOFOLLOW
+ * - verify that file xattr has not been set
+ * - verify that symlink xattr has been set
+ */
+
+#include <sys/xattr.h>
+
+#include "tst_test.h"
+#include "lapi/xattr.h"
+#include "lapi/fcntl.h"
+
+#define FNAME "ltp_file"
+#define SNAME "ltp_symbolic_file"
+#define XATTR_TEST_KEY "trusted.ltptestkey"
+#define XATTR_TEST_VALUE "ltprulez"
+#define XATTR_TEST_VALUE_SIZE 8
+
+static struct xattr_args *args;
+static int tmpdir_fd = -1;
+
+static struct tcase {
+	char *dst_set;
+	char *dst_noset;
+	int at_flags;
+} tcases[] = {
+	{
+		.dst_set = FNAME,
+		.dst_noset = SNAME,
+		.at_flags = 0,
+	},
+	{
+		.dst_set = SNAME,
+		.dst_noset = FNAME,
+		.at_flags = AT_SYMLINK_NOFOLLOW,
+	}
+};
+
+static void expect_xattr(const char *fname)
+{
+	int ret;
+	char buff[XATTR_TEST_VALUE_SIZE];
+
+	tst_res(TINFO, "Check if %s has xattr", fname);
+
+	memset(args, 0, sizeof(*args));
+	memset(buff, 0, XATTR_TEST_VALUE_SIZE);
+
+	args->value = buff;
+	args->size = XATTR_TEST_VALUE_SIZE;
+
+	ret = SAFE_GETXATTRAT(tmpdir_fd, fname, AT_SYMLINK_NOFOLLOW,
+		XATTR_TEST_KEY, args, sizeof(*args));
+
+	TST_EXP_EQ_LI(ret, XATTR_TEST_VALUE_SIZE);
+	TST_EXP_EQ_LI(args->size, XATTR_TEST_VALUE_SIZE);
+	TST_EXP_EQ_LI(args->flags, 0);
+	TST_EXP_EQ_STRN(args->value, XATTR_TEST_VALUE, XATTR_TEST_VALUE_SIZE);
+}
+
+static void expect_no_xattr(const char *fname)
+{
+	char buff[XATTR_TEST_VALUE_SIZE];
+
+	tst_res(TINFO, "Check if %s has no xattr", fname);
+
+	memset(args, 0, sizeof(*args));
+	memset(buff, 0, XATTR_TEST_VALUE_SIZE);
+
+	args->value = buff;
+	args->size = 0;
+
+	TST_EXP_FAIL(tst_syscall(__NR_getxattrat, tmpdir_fd, fname,
+		AT_SYMLINK_NOFOLLOW, XATTR_TEST_KEY, args, sizeof(*args)),
+		ENODATA);
+
+	TST_EXP_EQ_LI(args->size, 0);
+	TST_EXP_EQ_LI(args->flags, 0);
+	TST_EXP_EQ_STRN(args->value, "\0", 1);
+}
+
+static void run(unsigned int i)
+{
+	struct tcase *tc = &tcases[i];
+
+	args->value = XATTR_TEST_VALUE;
+	args->size = XATTR_TEST_VALUE_SIZE;
+	args->flags = XATTR_CREATE;
+
+	tst_res(TINFO, "Setting xattr '%s' in %s (flags=%s)",
+		XATTR_TEST_KEY, SNAME,
+		!tc->at_flags ? "0" : "AT_SYMLINK_NOFOLLOW");
+
+	SAFE_SETXATTRAT(tmpdir_fd, SNAME, tc->at_flags, XATTR_TEST_KEY,
+		 args, sizeof(*args));
+
+	expect_xattr(tc->dst_set);
+	expect_no_xattr(tc->dst_noset);
+
+	SAFE_REMOVEXATTRAT(tmpdir_fd, tc->dst_set, tc->at_flags,
+		XATTR_TEST_KEY);
+}
+
+static void setup(void)
+{
+	char *tmpdir;
+
+	tmpdir = tst_tmpdir_path();
+	tmpdir_fd = SAFE_OPEN(tmpdir, O_DIRECTORY);
+
+	SAFE_TOUCH(FNAME, 0777, NULL);
+	SAFE_SYMLINK(FNAME, SNAME);
+}
+
+static void cleanup(void)
+{
+	if (tmpdir_fd != -1)
+		SAFE_CLOSE(tmpdir_fd);
+
+	SAFE_UNLINK(SNAME);
+	SAFE_UNLINK(FNAME);
+}
+
+static struct tst_test test = {
+	.test = run,
+	.setup = setup,
+	.cleanup = cleanup,
+	.needs_tmpdir = 1,
+	.needs_root = 1,
+	.tcnt = ARRAY_SIZE(tcases),
+	.bufs = (struct tst_buffers []) {
+		{&args, .size = sizeof(struct xattr_args)},
+		{},
+	}
+};

-- 
2.43.0