Camera: Fix race between initialize() and statusCallback (take 2)

Cache the HAL status callback before provider initialization is
complete, and once initialization is complete, send all cached
callbacks.

Test: Camera CTS
Bug: 159201665
Change-Id: Ida86fe908f456832b9cba314d299bab056bc52a2
diff --git a/services/camera/libcameraservice/common/CameraProviderManager.cpp b/services/camera/libcameraservice/common/CameraProviderManager.cpp
index f115fd8..876d70d 100644
--- a/services/camera/libcameraservice/common/CameraProviderManager.cpp
+++ b/services/camera/libcameraservice/common/CameraProviderManager.cpp
@@ -1453,7 +1453,40 @@
     ALOGI("Camera provider %s ready with %zu camera devices",
             mProviderName.c_str(), mDevices.size());
 
-    mInitialized = true;
+    // Process cached status callbacks
+    std::unique_ptr<std::vector<CameraStatusInfoT>> cachedStatus =
+            std::make_unique<std::vector<CameraStatusInfoT>>();
+    {
+        std::lock_guard<std::mutex> lock(mInitLock);
+
+        for (auto& statusInfo : mCachedStatus) {
+            std::string id, physicalId;
+            status_t res = OK;
+            if (statusInfo.isPhysicalCameraStatus) {
+                res = physicalCameraDeviceStatusChangeLocked(&id, &physicalId,
+                    statusInfo.cameraId, statusInfo.physicalCameraId, statusInfo.status);
+            } else {
+                res = cameraDeviceStatusChangeLocked(&id, statusInfo.cameraId, statusInfo.status);
+            }
+            if (res == OK) {
+                cachedStatus->emplace_back(statusInfo.isPhysicalCameraStatus,
+                        id.c_str(), physicalId.c_str(), statusInfo.status);
+            }
+        }
+        mCachedStatus.clear();
+
+        mInitialized = true;
+    }
+
+    // The cached status change callbacks cannot be fired directly from this
+    // function, due to same-thread deadlock trying to acquire mInterfaceMutex
+    // twice.
+    if (listener != nullptr) {
+        mInitialStatusCallbackFuture = std::async(std::launch::async,
+                &CameraProviderManager::ProviderInfo::notifyInitialStatusChange, this,
+                listener, std::move(cachedStatus));
+    }
+
     return OK;
 }
 
@@ -1731,103 +1764,139 @@
         CameraDeviceStatus newStatus) {
     sp<StatusListener> listener;
     std::string id;
-    bool initialized = false;
+    std::lock_guard<std::mutex> lock(mInitLock);
+
+    if (!mInitialized) {
+        mCachedStatus.emplace_back(false /*isPhysicalCameraStatus*/,
+                cameraDeviceName.c_str(), std::string().c_str(), newStatus);
+        return hardware::Void();
+    }
+
     {
         std::lock_guard<std::mutex> lock(mLock);
-        bool known = false;
-        for (auto& deviceInfo : mDevices) {
-            if (deviceInfo->mName == cameraDeviceName) {
-                ALOGI("Camera device %s status is now %s, was %s", cameraDeviceName.c_str(),
-                        deviceStatusToString(newStatus), deviceStatusToString(deviceInfo->mStatus));
-                deviceInfo->mStatus = newStatus;
-                // TODO: Handle device removal (NOT_PRESENT)
-                id = deviceInfo->mId;
-                known = true;
-                break;
-            }
-        }
-        // Previously unseen device; status must not be NOT_PRESENT
-        if (!known) {
-            if (newStatus == CameraDeviceStatus::NOT_PRESENT) {
-                ALOGW("Camera provider %s says an unknown camera device %s is not present. Curious.",
-                    mProviderName.c_str(), cameraDeviceName.c_str());
-                return hardware::Void();
-            }
-            addDevice(cameraDeviceName, newStatus, &id);
-        } else if (newStatus == CameraDeviceStatus::NOT_PRESENT) {
-            removeDevice(id);
+        if (OK != cameraDeviceStatusChangeLocked(&id, cameraDeviceName, newStatus)) {
+            return hardware::Void();
         }
         listener = mManager->getStatusListener();
-        initialized = mInitialized;
-        if (reCacheConcurrentStreamingCameraIdsLocked() != OK) {
-            ALOGE("%s: CameraProvider %s could not re-cache concurrent streaming camera id list ",
-                      __FUNCTION__, mProviderName.c_str());
-        }
     }
+
     // Call without lock held to allow reentrancy into provider manager
-    // Don't send the callback if providerInfo hasn't been initialized.
-    // CameraService will initialize device status after provider is
-    // initialized
-    if (listener != nullptr && initialized) {
+    if (listener != nullptr) {
         listener->onDeviceStatusChanged(String8(id.c_str()), newStatus);
     }
+
     return hardware::Void();
 }
 
+status_t CameraProviderManager::ProviderInfo::cameraDeviceStatusChangeLocked(
+        std::string* id, const hardware::hidl_string& cameraDeviceName,
+        CameraDeviceStatus newStatus) {
+    bool known = false;
+    std::string cameraId;
+    for (auto& deviceInfo : mDevices) {
+        if (deviceInfo->mName == cameraDeviceName) {
+            ALOGI("Camera device %s status is now %s, was %s", cameraDeviceName.c_str(),
+                    deviceStatusToString(newStatus), deviceStatusToString(deviceInfo->mStatus));
+            deviceInfo->mStatus = newStatus;
+            // TODO: Handle device removal (NOT_PRESENT)
+            cameraId = deviceInfo->mId;
+            known = true;
+            break;
+        }
+    }
+    // Previously unseen device; status must not be NOT_PRESENT
+    if (!known) {
+        if (newStatus == CameraDeviceStatus::NOT_PRESENT) {
+            ALOGW("Camera provider %s says an unknown camera device %s is not present. Curious.",
+                mProviderName.c_str(), cameraDeviceName.c_str());
+            return BAD_VALUE;
+        }
+        addDevice(cameraDeviceName, newStatus, &cameraId);
+    } else if (newStatus == CameraDeviceStatus::NOT_PRESENT) {
+        removeDevice(cameraId);
+    }
+    if (reCacheConcurrentStreamingCameraIdsLocked() != OK) {
+        ALOGE("%s: CameraProvider %s could not re-cache concurrent streaming camera id list ",
+                  __FUNCTION__, mProviderName.c_str());
+    }
+    *id = cameraId;
+    return OK;
+}
+
 hardware::Return<void> CameraProviderManager::ProviderInfo::physicalCameraDeviceStatusChange(
         const hardware::hidl_string& cameraDeviceName,
         const hardware::hidl_string& physicalCameraDeviceName,
         CameraDeviceStatus newStatus) {
     sp<StatusListener> listener;
     std::string id;
+    std::string physicalId;
+    std::lock_guard<std::mutex> lock(mInitLock);
+
+    if (!mInitialized) {
+        mCachedStatus.emplace_back(true /*isPhysicalCameraStatus*/, cameraDeviceName,
+                physicalCameraDeviceName, newStatus);
+        return hardware::Void();
+    }
+
     {
         std::lock_guard<std::mutex> lock(mLock);
-        if (!mInitialized) return hardware::Void();
 
-        bool known = false;
-        for (auto& deviceInfo : mDevices) {
-            if (deviceInfo->mName == cameraDeviceName) {
-                id = deviceInfo->mId;
-
-                if (!deviceInfo->mIsLogicalCamera) {
-                    ALOGE("%s: Invalid combination of camera id %s, physical id %s",
-                            __FUNCTION__, id.c_str(), physicalCameraDeviceName.c_str());
-                    return hardware::Void();
-                }
-                if (std::find(deviceInfo->mPhysicalIds.begin(), deviceInfo->mPhysicalIds.end(),
-                        physicalCameraDeviceName) == deviceInfo->mPhysicalIds.end()) {
-                    ALOGE("%s: Invalid combination of camera id %s, physical id %s",
-                            __FUNCTION__, id.c_str(), physicalCameraDeviceName.c_str());
-                    return hardware::Void();
-                }
-                ALOGI("Camera device %s physical device %s status is now %s",
-                        cameraDeviceName.c_str(), physicalCameraDeviceName.c_str(),
-                        deviceStatusToString(newStatus));
-                known = true;
-                break;
-            }
-        }
-        // Previously unseen device; status must not be NOT_PRESENT
-        if (!known) {
-            ALOGW("Camera provider %s says an unknown camera device %s-%s is not present. Curious.",
-                    mProviderName.c_str(), cameraDeviceName.c_str(),
-                    physicalCameraDeviceName.c_str());
+        if (OK != physicalCameraDeviceStatusChangeLocked(&id, &physicalId, cameraDeviceName,
+                physicalCameraDeviceName, newStatus)) {
             return hardware::Void();
         }
+
         listener = mManager->getStatusListener();
     }
     // Call without lock held to allow reentrancy into provider manager
-    // Don't send the callback if providerInfo hasn't been initialized.
-    // CameraService will initialize device status after provider is
-    // initialized
     if (listener != nullptr) {
-        String8 physicalId(physicalCameraDeviceName.c_str());
         listener->onDeviceStatusChanged(String8(id.c_str()),
-                physicalId, newStatus);
+                String8(physicalId.c_str()), newStatus);
     }
     return hardware::Void();
 }
 
+status_t CameraProviderManager::ProviderInfo::physicalCameraDeviceStatusChangeLocked(
+            std::string* id, std::string* physicalId,
+            const hardware::hidl_string& cameraDeviceName,
+            const hardware::hidl_string& physicalCameraDeviceName,
+            CameraDeviceStatus newStatus) {
+    bool known = false;
+    std::string cameraId;
+    for (auto& deviceInfo : mDevices) {
+        if (deviceInfo->mName == cameraDeviceName) {
+            cameraId = deviceInfo->mId;
+            if (!deviceInfo->mIsLogicalCamera) {
+                ALOGE("%s: Invalid combination of camera id %s, physical id %s",
+                        __FUNCTION__, cameraId.c_str(), physicalCameraDeviceName.c_str());
+                return BAD_VALUE;
+            }
+            if (std::find(deviceInfo->mPhysicalIds.begin(), deviceInfo->mPhysicalIds.end(),
+                    physicalCameraDeviceName) == deviceInfo->mPhysicalIds.end()) {
+                ALOGE("%s: Invalid combination of camera id %s, physical id %s",
+                        __FUNCTION__, cameraId.c_str(), physicalCameraDeviceName.c_str());
+                return BAD_VALUE;
+            }
+            ALOGI("Camera device %s physical device %s status is now %s",
+                    cameraDeviceName.c_str(), physicalCameraDeviceName.c_str(),
+                    deviceStatusToString(newStatus));
+            known = true;
+            break;
+        }
+    }
+    // Previously unseen device; status must not be NOT_PRESENT
+    if (!known) {
+        ALOGW("Camera provider %s says an unknown camera device %s-%s is not present. Curious.",
+                mProviderName.c_str(), cameraDeviceName.c_str(),
+                physicalCameraDeviceName.c_str());
+        return BAD_VALUE;
+    }
+
+    *id = cameraId;
+    *physicalId = physicalCameraDeviceName.c_str();
+    return OK;
+}
+
 hardware::Return<void> CameraProviderManager::ProviderInfo::torchModeStatusChange(
         const hardware::hidl_string& cameraDeviceName,
         TorchModeStatus newStatus) {
@@ -1982,6 +2051,20 @@
     return INVALID_OPERATION;
 }
 
+void CameraProviderManager::ProviderInfo::notifyInitialStatusChange(
+        sp<StatusListener> listener,
+        std::unique_ptr<std::vector<CameraStatusInfoT>> cachedStatus) {
+    for (auto& statusInfo : *cachedStatus) {
+        if (statusInfo.isPhysicalCameraStatus) {
+            listener->onDeviceStatusChanged(String8(statusInfo.cameraId.c_str()),
+                    String8(statusInfo.physicalCameraId.c_str()), statusInfo.status);
+        } else {
+            listener->onDeviceStatusChanged(
+                    String8(statusInfo.cameraId.c_str()), statusInfo.status);
+        }
+    }
+}
+
 template<class DeviceInfoT>
 std::unique_ptr<CameraProviderManager::ProviderInfo::DeviceInfo>
     CameraProviderManager::ProviderInfo::initializeDeviceInfo(
@@ -2685,9 +2768,11 @@
 
 
 CameraProviderManager::ProviderInfo::~ProviderInfo() {
+    if (mInitialStatusCallbackFuture.valid()) {
+        mInitialStatusCallbackFuture.wait();
+    }
     // Destruction of ProviderInfo is only supposed to happen when the respective
     // CameraProvider interface dies, so do not unregister callbacks.
-
 }
 
 status_t CameraProviderManager::mapToStatusT(const Status& s)  {
diff --git a/services/camera/libcameraservice/common/CameraProviderManager.h b/services/camera/libcameraservice/common/CameraProviderManager.h
index 281cb3d..a0e5f8f 100644
--- a/services/camera/libcameraservice/common/CameraProviderManager.h
+++ b/services/camera/libcameraservice/common/CameraProviderManager.h
@@ -22,6 +22,7 @@
 #include <unordered_set>
 #include <string>
 #include <mutex>
+#include <future>
 
 #include <camera/camera2/ConcurrentCamera.h>
 #include <camera/CameraParameters2.h>
@@ -403,6 +404,15 @@
                 const hardware::hidl_string& physicalCameraDeviceName,
                 hardware::camera::common::V1_0::CameraDeviceStatus newStatus) override;
 
+        status_t cameraDeviceStatusChangeLocked(
+                std::string* id, const hardware::hidl_string& cameraDeviceName,
+                hardware::camera::common::V1_0::CameraDeviceStatus newStatus);
+        status_t physicalCameraDeviceStatusChangeLocked(
+                std::string* id, std::string* physicalId,
+                const hardware::hidl_string& cameraDeviceName,
+                const hardware::hidl_string& physicalCameraDeviceName,
+                hardware::camera::common::V1_0::CameraDeviceStatus newStatus);
+
         // hidl_death_recipient interface - this locks the parent mInterfaceMutex
         virtual void serviceDied(uint64_t cookie, const wp<hidl::base::V1_0::IBase>& who) override;
 
@@ -598,7 +608,27 @@
 
         CameraProviderManager *mManager;
 
+        struct CameraStatusInfoT {
+            bool isPhysicalCameraStatus = false;
+            hardware::hidl_string cameraId;
+            hardware::hidl_string physicalCameraId;
+            hardware::camera::common::V1_0::CameraDeviceStatus status;
+            CameraStatusInfoT(bool isForPhysicalCamera, const hardware::hidl_string& id,
+                    const hardware::hidl_string& physicalId,
+                    hardware::camera::common::V1_0::CameraDeviceStatus s) :
+                    isPhysicalCameraStatus(isForPhysicalCamera), cameraId(id),
+                    physicalCameraId(physicalId), status(s) {}
+        };
+
+        // Lock to synchronize between initialize() and camera status callbacks
+        std::mutex mInitLock;
         bool mInitialized = false;
+        std::vector<CameraStatusInfoT> mCachedStatus;
+        // End of scope for mInitLock
+
+        std::future<void> mInitialStatusCallbackFuture;
+        void notifyInitialStatusChange(sp<StatusListener> listener,
+                std::unique_ptr<std::vector<CameraStatusInfoT>> cachedStatus);
 
         std::vector<std::unordered_set<std::string>> mConcurrentCameraIdCombinations;