kselftest: alsa: Add test case for writing invalid values

Attempt to write various invalid values for control types we know about and
check that something sensible happens. The ABI isn't quite as clearly
defined as one might like, rather than generating an error when an invalid
value is written many devices will silently rewrite the value into one that
is valid for the control. The exact value chosen is not predictable so in
the case the write succeeds we just check that the value we read back is
one that is valid for the control.
Reviewed-by: Shuah Khan <skhan@linuxfoundation.org>
Signed-off-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20220125162824.3816659-1-broonie@kernel.orgSigned-off-by: Takashi Iwai <tiwai@suse.de>

tools/testing/selftests/alsa/mixer-test.c

@@ -13,6 +13,7 @@
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdbool.h>
+#include <limits.h>
 #include <string.h>
 #include <getopt.h>
 #include <stdarg.h>
@@ -26,7 +27,7 @@
 
 #include "../kselftest.h"
 
-#define TESTS_PER_CONTROL 3
+#define TESTS_PER_CONTROL 4
 
 struct card_data {
 	snd_ctl_t *handle;
@@ -679,6 +680,224 @@ void test_ctl_write_valid(struct ctl_data *ctl)
 			 ctl->card->card, ctl->elem);
 }
 
+bool test_ctl_write_invalid_value(struct ctl_data *ctl,
+				  snd_ctl_elem_value_t *val)
+{
+	int err;
+	long val_read;
+
+	/* Ideally this will fail... */
+	err = snd_ctl_elem_write(ctl->card->handle, val);
+	if (err < 0)
+		return false;
+
+	/* ...but some devices will clamp to an in range value */
+	err = snd_ctl_elem_read(ctl->card->handle, val);
+	if (err < 0) {
+		ksft_print_msg("%s failed to read: %s\n",
+			       ctl->name, snd_strerror(err));
+		return true;
+	}
+
+	return !ctl_value_valid(ctl, val);
+}
+
+bool test_ctl_write_invalid_boolean(struct ctl_data *ctl)
+{
+	int err, i;
+	long val_read;
+	bool fail = false;
+	snd_ctl_elem_value_t *val;
+	snd_ctl_elem_value_alloca(&val);
+
+	for (i = 0; i < snd_ctl_elem_info_get_count(ctl->info); i++) {
+		snd_ctl_elem_value_copy(val, ctl->def_val);
+		snd_ctl_elem_value_set_boolean(val, i, 2);
+
+		if (test_ctl_write_invalid_value(ctl, val))
+			fail = true;
+	}
+
+	return !fail;
+}
+
+bool test_ctl_write_invalid_integer(struct ctl_data *ctl)
+{
+	int i;
+	bool fail = false;
+	snd_ctl_elem_value_t *val;
+	snd_ctl_elem_value_alloca(&val);
+
+	for (i = 0; i < snd_ctl_elem_info_get_count(ctl->info); i++) {
+		if (snd_ctl_elem_info_get_min(ctl->info) != LONG_MIN) {
+			/* Just under range */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer(val, i,
+			       snd_ctl_elem_info_get_min(ctl->info) - 1);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+
+			/* Minimum representable value */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer(val, i, LONG_MIN);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+		}
+
+		if (snd_ctl_elem_info_get_max(ctl->info) != LONG_MAX) {
+			/* Just over range */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer(val, i,
+			       snd_ctl_elem_info_get_max(ctl->info) + 1);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+
+			/* Maximum representable value */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer(val, i, LONG_MAX);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+		}
+	}
+
+	return !fail;
+}
+
+bool test_ctl_write_invalid_integer64(struct ctl_data *ctl)
+{
+	int i;
+	bool fail = false;
+	snd_ctl_elem_value_t *val;
+	snd_ctl_elem_value_alloca(&val);
+
+	for (i = 0; i < snd_ctl_elem_info_get_count(ctl->info); i++) {
+		if (snd_ctl_elem_info_get_min64(ctl->info) != LLONG_MIN) {
+			/* Just under range */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer64(val, i,
+				snd_ctl_elem_info_get_min64(ctl->info) - 1);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+
+			/* Minimum representable value */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer64(val, i, LLONG_MIN);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+		}
+
+		if (snd_ctl_elem_info_get_max64(ctl->info) != LLONG_MAX) {
+			/* Just over range */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer64(val, i,
+				snd_ctl_elem_info_get_max64(ctl->info) + 1);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+
+			/* Maximum representable value */
+			snd_ctl_elem_value_copy(val, ctl->def_val);
+			snd_ctl_elem_value_set_integer64(val, i, LLONG_MAX);
+
+			if (test_ctl_write_invalid_value(ctl, val))
+				fail = true;
+		}
+	}
+
+	return !fail;
+}
+
+bool test_ctl_write_invalid_enumerated(struct ctl_data *ctl)
+{
+	int err, i;
+	unsigned int val_read;
+	bool fail = false;
+	snd_ctl_elem_value_t *val;
+	snd_ctl_elem_value_alloca(&val);
+
+	snd_ctl_elem_value_set_id(val, ctl->id);
+
+	for (i = 0; i < snd_ctl_elem_info_get_count(ctl->info); i++) {
+		/* One beyond maximum */
+		snd_ctl_elem_value_copy(val, ctl->def_val);
+		snd_ctl_elem_value_set_enumerated(val, i,
+				  snd_ctl_elem_info_get_items(ctl->info));
+
+		if (test_ctl_write_invalid_value(ctl, val))
+			fail = true;
+
+		/* Maximum representable value */
+		snd_ctl_elem_value_copy(val, ctl->def_val);
+		snd_ctl_elem_value_set_enumerated(val, i, UINT_MAX);
+
+		if (test_ctl_write_invalid_value(ctl, val))
+			fail = true;
+
+	}
+
+	return !fail;
+}
+
+
+void test_ctl_write_invalid(struct ctl_data *ctl)
+{
+	bool pass;
+	int err;
+
+	/* If the control is turned off let's be polite */
+	if (snd_ctl_elem_info_is_inactive(ctl->info)) {
+		ksft_print_msg("%s is inactive\n", ctl->name);
+		ksft_test_result_skip("write_invalid.%d.%d\n",
+				      ctl->card->card, ctl->elem);
+		return;
+	}
+
+	if (!snd_ctl_elem_info_is_writable(ctl->info)) {
+		ksft_print_msg("%s is not writeable\n", ctl->name);
+		ksft_test_result_skip("write_invalid.%d.%d\n",
+				      ctl->card->card, ctl->elem);
+		return;
+	}
+
+	switch (snd_ctl_elem_info_get_type(ctl->info)) {
+	case SND_CTL_ELEM_TYPE_BOOLEAN:
+		pass = test_ctl_write_invalid_boolean(ctl);
+		break;
+
+	case SND_CTL_ELEM_TYPE_INTEGER:
+		pass = test_ctl_write_invalid_integer(ctl);
+		break;
+
+	case SND_CTL_ELEM_TYPE_INTEGER64:
+		pass = test_ctl_write_invalid_integer64(ctl);
+		break;
+
+	case SND_CTL_ELEM_TYPE_ENUMERATED:
+		pass = test_ctl_write_invalid_enumerated(ctl);
+		break;
+
+	default:
+		/* No tests for this yet */
+		ksft_test_result_skip("write_invalid.%d.%d\n",
+				      ctl->card->card, ctl->elem);
+		return;
+	}
+
+	/* Restore the default value to minimise disruption */
+	err = write_and_verify(ctl, ctl->def_val, NULL);
+	if (err < 0)
+		pass = false;
+
+	ksft_test_result(pass, "write_invalid.%d.%d\n",
+			 ctl->card->card, ctl->elem);
+}
+
 int main(void)
 {
 	struct ctl_data *ctl;
@@ -697,6 +916,7 @@ int main(void)
 		test_ctl_get_value(ctl);
 		test_ctl_write_default(ctl);
 		test_ctl_write_valid(ctl);
+		test_ctl_write_invalid(ctl);
 	}
 
 	ksft_exit_pass();