[PATCH v4 01/10] string: provide strends()

Bartosz Golaszewski
2025-11-12T13:55:42Z

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

Implement a function for checking if a string ends with a different
string and add its kunit test cases.

Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
include/linux/string.h | 18 ++++++++++++++++++
lib/tests/string_kunit.c | 13 +++++++++++++
2 files changed, 31 insertions(+)

diff --git a/include/linux/string.h b/include/linux/string.h
index fdd3442c6bcbd786e177b6e87358e1065a0ffafc..929d05d1247c76eb9011fe34250b487834b2d3c9 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -562,4 +562,22 @@ static inline bool strstarts(const char *str, const char *prefix)
return strncmp(str, prefix, strlen(prefix)) == 0;
}

+/**
+ * strends - Check if a string ends with another string.
+ * @str - NULL-terminated string to check against @suffix
+ * @suffix - NULL-terminated string defining the suffix to look for in @str
+ *
+ * Returns:
+ * True if @str ends with @suffix. False in all other cases.
+ */
+static inline bool strends(const char *str, const char *suffix)
+{
+ unsigned int str_len = strlen(str), suffix_len = strlen(suffix);
+
+ if (str_len < suffix_len)
+ return false;
+
+ return !(strcmp(str + str_len - suffix_len, suffix));
+}
+
#endif /* _LINUX_STRING_H_ */
diff --git a/lib/tests/string_kunit.c b/lib/tests/string_kunit.c
index 0ed7448a26d3aa0fe9e2a6a894d4c49c2c0b86e0..f9a8e557ba7734c9848d58ff986407d8000f52ee 100644
--- a/lib/tests/string_kunit.c
+++ b/lib/tests/string_kunit.c
@@ -602,6 +602,18 @@ static void string_test_memtostr(struct kunit *test)
KUNIT_EXPECT_EQ(test, dest[7], '\0');
}

+static void string_test_strends(struct kunit *test)
+{
+ KUNIT_EXPECT_TRUE(test, strends("foo-bar", "bar"));
+ KUNIT_EXPECT_TRUE(test, strends("foo-bar", "-bar"));
+ KUNIT_EXPECT_TRUE(test, strends("foobar", "foobar"));
+ KUNIT_EXPECT_TRUE(test, strends("foobar", ""));
+ KUNIT_EXPECT_FALSE(test, strends("bar", "foobar"));
+ KUNIT_EXPECT_FALSE(test, strends("", "foo"));
+ KUNIT_EXPECT_FALSE(test, strends("foobar", "ba"));
+ KUNIT_EXPECT_TRUE(test, strends("", ""));
+}
+
static struct kunit_case string_test_cases[] = {
KUNIT_CASE(string_test_memset16),
KUNIT_CASE(string_test_memset32),
@@ -623,6 +635,7 @@ static struct kunit_case string_test_cases[] = {
KUNIT_CASE(string_test_strlcat),
KUNIT_CASE(string_test_strtomem),
KUNIT_CASE(string_test_memtostr),
+ KUNIT_CASE(string_test_strends),
{}
};

--
2.51.0