[PATCH 6.1.y 1/2] lib/tests: extend cmdline KUnit with next_arg() tests

[Sasha Levin <sashal@kernel.org>]

From: Shuvam Pandey <shuvampandey1@gmail.com>

[ Upstream commit dcc8a57815534e3844f342b28ecfb6e626a816a0 ]

The cmdline KUnit suite covers get_option() and get_options(), but it
does not exercise next_arg().

Extend the suite with one test for a quoted value containing spaces and
one regression test for a bare quote token after a normal parameter.

The regression test covers the bare quote token path fixed by commit
9847f21225c4 ("lib/cmdline: avoid page fault in next_arg").

[shuvampandey1@gmail.com: extend cmdline next_arg() coverage with mixed tokens]
  Link: https://lore.kernel.org/20260316211249.88601-1-shuvampandey1@gmail.com
Link: https://lore.kernel.org/20260316101227.15807-1-shuvampandey1@gmail.com
Signed-off-by: Shuvam Pandey <shuvampandey1@gmail.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Cc: Neel Natu <neelnatu@google.com>
Cc: Dmitry Antipov <dmantipov@yandex.ru>
Cc: "Darrick J. Wong" <djwong@kernel.org>
Cc: Kees Cook <kees@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stable-dep-of: 5d72266218b1 ("lib/cmdline: fix get_options() count and overflow with large ranges")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 lib/cmdline_kunit.c | 62 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 62 insertions(+)

diff --git a/lib/cmdline_kunit.c b/lib/cmdline_kunit.c
index 705b82736be08..20d525aa23eda 100644
--- a/lib/cmdline_kunit.c
+++ b/lib/cmdline_kunit.c
@@ -139,11 +139,73 @@ static void cmdline_test_range(struct kunit *test)
 	} while (++i < ARRAY_SIZE(cmdline_test_range_strings));
 }
 
+static void cmdline_test_next_arg_quoted_value(struct kunit *test)
+{
+	char in[] = "foo=\"bar baz\" qux=1";
+	char *next, *param, *val;
+
+	next = next_arg(in, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "foo");
+	KUNIT_ASSERT_NOT_NULL(test, val);
+	KUNIT_EXPECT_STREQ(test, val, "bar baz");
+	KUNIT_EXPECT_STREQ(test, next, "qux=1");
+
+	next = next_arg(next, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "qux");
+	KUNIT_ASSERT_NOT_NULL(test, val);
+	KUNIT_EXPECT_STREQ(test, val, "1");
+	KUNIT_EXPECT_STREQ(test, next, "");
+}
+
+static void cmdline_test_next_arg_bare_quote_regression(struct kunit *test)
+{
+	char in[] = "foo=bar \"";
+	char *next, *param, *val;
+
+	next = next_arg(in, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "foo");
+	KUNIT_ASSERT_NOT_NULL(test, val);
+	KUNIT_EXPECT_STREQ(test, val, "bar");
+	KUNIT_EXPECT_STREQ(test, next, "\"");
+
+	/* This hits the i == 0 quoted-token case fixed by 9847f21225c4. */
+	next = next_arg(next, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "");
+	KUNIT_EXPECT_PTR_EQ(test, val, NULL);
+	KUNIT_EXPECT_STREQ(test, next, "");
+}
+
+static void cmdline_test_next_arg_mixed_tokens(struct kunit *test)
+{
+	char in[] = "bbb= jjj kkk=\"a=b\"";
+	char *next, *param, *val;
+
+	next = next_arg(in, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "bbb");
+	KUNIT_ASSERT_NOT_NULL(test, val);
+	KUNIT_EXPECT_STREQ(test, val, "");
+	KUNIT_EXPECT_STREQ(test, next, "jjj kkk=\"a=b\"");
+
+	next = next_arg(next, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "jjj");
+	KUNIT_EXPECT_NULL(test, val);
+	KUNIT_EXPECT_STREQ(test, next, "kkk=\"a=b\"");
+
+	next = next_arg(next, &param, &val);
+	KUNIT_EXPECT_STREQ(test, param, "kkk");
+	KUNIT_ASSERT_NOT_NULL(test, val);
+	KUNIT_EXPECT_STREQ(test, val, "a=b");
+	KUNIT_EXPECT_STREQ(test, next, "");
+}
+
 static struct kunit_case cmdline_test_cases[] = {
 	KUNIT_CASE(cmdline_test_noint),
 	KUNIT_CASE(cmdline_test_lead_int),
 	KUNIT_CASE(cmdline_test_tail_int),
 	KUNIT_CASE(cmdline_test_range),
+	KUNIT_CASE(cmdline_test_next_arg_quoted_value),
+	KUNIT_CASE(cmdline_test_next_arg_bare_quote_regression),
+	KUNIT_CASE(cmdline_test_next_arg_mixed_tokens),
 	{}
 };
 
-- 
2.53.0