Add rear fps virtual HAL.

Bug: 228638448
Test: atest FakeFingerprintEngineTest
Test: manual (see README.md)

Change-Id: Ifecf6b5667352eb2127f820bfde47c7d325ab1b2
diff --git a/biometrics/fingerprint/aidl/default/FakeFingerprintEngine.cpp b/biometrics/fingerprint/aidl/default/FakeFingerprintEngine.cpp
new file mode 100644
index 0000000..d1fe183
--- /dev/null
+++ b/biometrics/fingerprint/aidl/default/FakeFingerprintEngine.cpp
@@ -0,0 +1,263 @@
+/*
+ * Copyright (C) 2021 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "FakeFingerprintEngine.h"
+
+#include <fingerprint.sysprop.h>
+#include "CancellationSignal.h"
+
+#include <android-base/logging.h>
+#include <chrono>
+#include <regex>
+#include <thread>
+
+#define SLEEP_MS(x) \
+    if (x > 0) std::this_thread::sleep_for(std::chrono::milliseconds(x))
+#define BEGIN_OP(x)            \
+    do {                       \
+        LOG(INFO) << __func__; \
+        SLEEP_MS(x);           \
+    } while (0)
+#define IS_TRUE(x) ((x == "1") || (x == "true"))
+
+// This is for non-test situations, such as casual cuttlefish users, that don't
+// set an explicit value.
+// Some operations (i.e. enroll, authenticate) will be executed in tight loops
+// by parts of the UI or fail if there is no latency. For example, the
+// fingerprint settings page constantly runs auth and the enrollment UI uses a
+// cancel/restart cycle that requires some latency while the activities change.
+#define DEFAULT_LATENCY 2000
+
+using namespace ::android::fingerprint::virt;
+using namespace ::aidl::android::hardware::biometrics::fingerprint;
+
+int64_t getSystemNanoTime() {
+    timespec now;
+    clock_gettime(CLOCK_MONOTONIC, &now);
+    return now.tv_sec * 1000000000LL + now.tv_nsec;
+}
+
+bool hasElapsed(int64_t start, int64_t durationMillis) {
+    auto now = getSystemNanoTime();
+    if (now < start) return true;
+    if (durationMillis <= 0) return true;
+    return ((now - start) / 1000000LL) > durationMillis;
+}
+
+std::vector<std::string> split(const std::string& str, const std::string& sep) {
+    std::regex regex(sep);
+    std::vector<std::string> parts(std::sregex_token_iterator(str.begin(), str.end(), regex, -1),
+                                   std::sregex_token_iterator());
+    return parts;
+}
+
+namespace aidl::android::hardware::biometrics::fingerprint {
+
+void FakeFingerprintEngine::generateChallengeImpl(ISessionCallback* cb) {
+    BEGIN_OP(0);
+    std::uniform_int_distribution<int64_t> dist;
+    auto challenge = dist(mRandom);
+    FingerprintHalProperties::challenge(challenge);
+    cb->onChallengeGenerated(challenge);
+}
+
+void FakeFingerprintEngine::revokeChallengeImpl(ISessionCallback* cb, int64_t challenge) {
+    BEGIN_OP(0);
+    FingerprintHalProperties::challenge({});
+    cb->onChallengeRevoked(challenge);
+}
+
+void FakeFingerprintEngine::enrollImpl(ISessionCallback* cb,
+                                       const keymaster::HardwareAuthToken& hat,
+                                       const std::future<void>& cancel) {
+    BEGIN_OP(FingerprintHalProperties::operation_enroll_latency().value_or(DEFAULT_LATENCY));
+
+    // Do proper HAT verification in the real implementation.
+    if (hat.mac.empty()) {
+        LOG(ERROR) << "Fail: hat";
+        cb->onError(Error::UNABLE_TO_PROCESS, 0 /* vendorError */);
+        return;
+    }
+
+    if (FingerprintHalProperties::operation_enroll_fails().value_or(false)) {
+        LOG(ERROR) << "Fail: operation_enroll_fails";
+        cb->onError(Error::VENDOR, 0 /* vendorError */);
+        return;
+    }
+
+    // format is "<id>:<progress_ms>,<progress_ms>,...:<result>
+    auto nextEnroll = FingerprintHalProperties::next_enrollment().value_or("");
+    auto parts = split(nextEnroll, ":");
+    if (parts.size() != 3) {
+        LOG(ERROR) << "Fail: invalid next_enrollment";
+        cb->onError(Error::VENDOR, 0 /* vendorError */);
+        return;
+    }
+    auto enrollmentId = std::stoi(parts[0]);
+    auto progress = split(parts[1], ",");
+    for (size_t i = 0; i < progress.size(); i++) {
+        auto left = progress.size() - i - 1;
+        SLEEP_MS(std::stoi(progress[i]));
+
+        if (shouldCancel(cancel)) {
+            LOG(ERROR) << "Fail: cancel";
+            cb->onError(Error::CANCELED, 0 /* vendorCode */);
+            return;
+        }
+
+        cb->onAcquired(AcquiredInfo::GOOD, 0 /* vendorCode */);
+        if (left == 0 && !IS_TRUE(parts[2])) {  // end and failed
+            LOG(ERROR) << "Fail: requested by caller: " << nextEnroll;
+            FingerprintHalProperties::next_enrollment({});
+            cb->onError(Error::UNABLE_TO_PROCESS, 0 /* vendorCode */);
+        } else {  // progress and update props if last time
+            if (left == 0) {
+                auto enrollments = FingerprintHalProperties::enrollments();
+                enrollments.emplace_back(enrollmentId);
+                FingerprintHalProperties::enrollments(enrollments);
+                FingerprintHalProperties::next_enrollment({});
+                LOG(INFO) << "Enrolled: " << enrollmentId;
+            }
+            cb->onEnrollmentProgress(enrollmentId, left);
+        }
+    }
+}
+
+void FakeFingerprintEngine::authenticateImpl(ISessionCallback* cb, int64_t /* operationId */,
+                                             const std::future<void>& cancel) {
+    BEGIN_OP(FingerprintHalProperties::operation_authenticate_latency().value_or(DEFAULT_LATENCY));
+
+    auto now = getSystemNanoTime();
+    int64_t duration = FingerprintHalProperties::operation_authenticate_duration().value_or(0);
+    do {
+        if (FingerprintHalProperties::operation_authenticate_fails().value_or(false)) {
+            LOG(ERROR) << "Fail: operation_authenticate_fails";
+            cb->onError(Error::VENDOR, 0 /* vendorError */);
+            return;
+        }
+
+        if (FingerprintHalProperties::lockout().value_or(false)) {
+            LOG(ERROR) << "Fail: lockout";
+            cb->onLockoutPermanent();
+            cb->onError(Error::HW_UNAVAILABLE, 0 /* vendorError */);
+            return;
+        }
+
+        if (shouldCancel(cancel)) {
+            LOG(ERROR) << "Fail: cancel";
+            cb->onError(Error::CANCELED, 0 /* vendorCode */);
+            return;
+        }
+
+        auto id = FingerprintHalProperties::enrollment_hit().value_or(0);
+        auto enrolls = FingerprintHalProperties::enrollments();
+        auto isEnrolled = std::find(enrolls.begin(), enrolls.end(), id) != enrolls.end();
+        if (id > 0 && isEnrolled) {
+            cb->onAuthenticationSucceeded(id, {} /* hat */);
+            return;
+        }
+
+        SLEEP_MS(100);
+    } while (!hasElapsed(now, duration));
+
+    LOG(ERROR) << "Fail: not enrolled";
+    cb->onAuthenticationFailed();
+    cb->onError(Error::UNABLE_TO_PROCESS, 0 /* vendorError */);
+}
+
+void FakeFingerprintEngine::detectInteractionImpl(ISessionCallback* cb,
+                                                  const std::future<void>& cancel) {
+    BEGIN_OP(FingerprintHalProperties::operation_detect_interaction_latency().value_or(
+            DEFAULT_LATENCY));
+
+    if (FingerprintHalProperties::operation_detect_interaction_fails().value_or(false)) {
+        LOG(ERROR) << "Fail: operation_detect_interaction_fails";
+        cb->onError(Error::VENDOR, 0 /* vendorError */);
+        return;
+    }
+
+    if (shouldCancel(cancel)) {
+        LOG(ERROR) << "Fail: cancel";
+        cb->onError(Error::CANCELED, 0 /* vendorCode */);
+        return;
+    }
+
+    auto id = FingerprintHalProperties::enrollment_hit().value_or(0);
+    auto enrolls = FingerprintHalProperties::enrollments();
+    auto isEnrolled = std::find(enrolls.begin(), enrolls.end(), id) != enrolls.end();
+    if (id <= 0 || !isEnrolled) {
+        LOG(ERROR) << "Fail: not enrolled";
+        cb->onError(Error::UNABLE_TO_PROCESS, 0 /* vendorError */);
+        return;
+    }
+
+    cb->onInteractionDetected();
+}
+
+void FakeFingerprintEngine::enumerateEnrollmentsImpl(ISessionCallback* cb) {
+    BEGIN_OP(0);
+
+    std::vector<int32_t> ids;
+    for (auto& enrollment : FingerprintHalProperties::enrollments()) {
+        auto id = enrollment.value_or(0);
+        if (id > 0) {
+            ids.push_back(id);
+        }
+    }
+
+    cb->onEnrollmentsEnumerated(ids);
+}
+
+void FakeFingerprintEngine::removeEnrollmentsImpl(ISessionCallback* cb,
+                                                  const std::vector<int32_t>& enrollmentIds) {
+    BEGIN_OP(0);
+
+    std::vector<std::optional<int32_t>> newEnrollments;
+    std::vector<int32_t> removed;
+    for (auto& enrollment : FingerprintHalProperties::enrollments()) {
+        auto id = enrollment.value_or(0);
+        if (std::find(enrollmentIds.begin(), enrollmentIds.end(), id) != enrollmentIds.end()) {
+            removed.push_back(id);
+        } else if (id > 0) {
+            newEnrollments.emplace_back(id);
+        }
+    }
+    FingerprintHalProperties::enrollments(newEnrollments);
+
+    cb->onEnrollmentsRemoved(enrollmentIds);
+}
+
+void FakeFingerprintEngine::getAuthenticatorIdImpl(ISessionCallback* cb) {
+    BEGIN_OP(0);
+    cb->onAuthenticatorIdRetrieved(FingerprintHalProperties::authenticator_id().value_or(0));
+}
+
+void FakeFingerprintEngine::invalidateAuthenticatorIdImpl(ISessionCallback* cb) {
+    BEGIN_OP(0);
+    auto id = FingerprintHalProperties::authenticator_id().value_or(0);
+    auto newId = id + 1;
+    FingerprintHalProperties::authenticator_id(newId);
+    cb->onAuthenticatorIdInvalidated(newId);
+}
+
+void FakeFingerprintEngine::resetLockoutImpl(ISessionCallback* cb,
+                                             const keymaster::HardwareAuthToken& /*hat*/) {
+    BEGIN_OP(0);
+    FingerprintHalProperties::lockout(false);
+    cb->onLockoutCleared();
+}
+
+}  // namespace aidl::android::hardware::biometrics::fingerprint