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libcutils: Use strnlen for default property values

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Add unit tests to test the corner cases.

Test: unit tests pass before and after the change.
Change-Id: Idafeb8354cd6c7db2a68cd398dafe153453a3940
This commit is contained in:
Myles Watson 2016-12-22 09:05:18 -08:00
parent 22c0962ab9
commit e67abec514
2 changed files with 53 additions and 7 deletions
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5
libcutils/properties.c
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@ -119,10 +119,7 @@ int property_get(const char *key, char *value, const char *default_value) {
return len; return len;
} }
if (default_value) { if (default_value) {
len = strlen(default_value); len = strnlen(default_value, PROPERTY_VALUE_MAX - 1);
if (len >= PROPERTY_VALUE_MAX) {
len = PROPERTY_VALUE_MAX - 1;
}
memcpy(value, default_value, len); memcpy(value, default_value, len);
value[len] = '\0'; value[len] = '\0';
} }

55
libcutils/tests/PropertiesTest.cpp
View file

@ -159,19 +159,68 @@ TEST_F(PropertiesTest, SetString) {
TEST_F(PropertiesTest, GetString) { TEST_F(PropertiesTest, GetString) {
// Try to use a default value that's too long => set fails // Try to use a default value that's too long => get truncates the value
{ {
ASSERT_OK(property_set(PROPERTY_TEST_KEY, "")); ASSERT_OK(property_set(PROPERTY_TEST_KEY, ""));
std::string maxLengthString = std::string(PROPERTY_VALUE_MAX-1, 'a'); std::string maxLengthString = std::string(PROPERTY_VALUE_MAX - 1, 'a');
std::string oneLongerString = std::string(PROPERTY_VALUE_MAX, 'a'); std::string oneLongerString = std::string(PROPERTY_VALUE_MAX, 'a');
// Expect that the value is truncated since it's too long (by 1) // Expect that the value is truncated since it's too long (by 1)
int len = property_get(PROPERTY_TEST_KEY, mValue, oneLongerString.c_str()); int len = property_get(PROPERTY_TEST_KEY, mValue, oneLongerString.c_str());
EXPECT_EQ(PROPERTY_VALUE_MAX-1, len); EXPECT_EQ(PROPERTY_VALUE_MAX - 1, len);
EXPECT_STREQ(maxLengthString.c_str(), mValue); EXPECT_STREQ(maxLengthString.c_str(), mValue);
ResetValue(); ResetValue();
} }
// Try to use a default value that's the max length => get succeeds
{
ASSERT_OK(property_set(PROPERTY_TEST_KEY, ""));
std::string maxLengthString = std::string(PROPERTY_VALUE_MAX - 1, 'b');
// Expect that the value matches maxLengthString
int len = property_get(PROPERTY_TEST_KEY, mValue, maxLengthString.c_str());
EXPECT_EQ(PROPERTY_VALUE_MAX - 1, len);
EXPECT_STREQ(maxLengthString.c_str(), mValue);
ResetValue();
}
// Try to use a default value of length one => get succeeds
{
ASSERT_OK(property_set(PROPERTY_TEST_KEY, ""));
std::string oneCharString = std::string(1, 'c');
// Expect that the value matches oneCharString
int len = property_get(PROPERTY_TEST_KEY, mValue, oneCharString.c_str());
EXPECT_EQ(1, len);
EXPECT_STREQ(oneCharString.c_str(), mValue);
ResetValue();
}
// Try to use a default value of length zero => get succeeds
{
ASSERT_OK(property_set(PROPERTY_TEST_KEY, ""));
std::string zeroCharString = std::string(0, 'd');
// Expect that the value matches oneCharString
int len = property_get(PROPERTY_TEST_KEY, mValue, zeroCharString.c_str());
EXPECT_EQ(0, len);
EXPECT_STREQ(zeroCharString.c_str(), mValue);
ResetValue();
}
// Try to use a NULL default value => get returns 0
{
ASSERT_OK(property_set(PROPERTY_TEST_KEY, ""));
// Expect a return value of 0
int len = property_get(PROPERTY_TEST_KEY, mValue, NULL);
EXPECT_EQ(0, len);
ResetValue();
}
} }
TEST_F(PropertiesTest, GetBool) { TEST_F(PropertiesTest, GetBool) {