1 files changed, 190 insertions, 0 deletions
diff --git a/libstats/pull_lazy/libstatspull_lazy.cpp b/libstats/pull_lazy/libstatspull_lazy.cpp
new file mode 100644
index 000000000..b11fceec1
--- /dev/null
+++ b/libstats/pull_lazy/libstatspull_lazy.cpp
@@ -0,0 +1,190 @@
+/*
+ * 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 "libstatspull_lazy.h"
+
+#include <mutex>
+
+#include <dlfcn.h>
+#include <stdatomic.h>
+
+#include "log/log.h"
+
+#include "stats_pull_atom_callback.h"
+
+// This file provides a lazy interface to libstatspull.so to address early boot dependencies.
+// Specifically bootanimation, surfaceflinger, and lmkd run before the statsd APEX is loaded and
+// libstatspull.so is in the statsd APEX.
+
+// Method pointers to libstatspull methods are held in an array which simplifies checking
+// all pointers are initialized.
+enum MethodIndex {
+    // PullAtomMetadata APIs in stats_pull_atom_callback.h.
+    k_AStatsManager_PullAtomMetadata_obtain,
+    k_AStatsManager_PullAtomMetadata_release,
+    k_AStatsManager_PullAtomMetadata_setCoolDownMillis,
+    k_AStatsManager_PullAtomMetadata_getCoolDownMillis,
+    k_AStatsManager_PullAtomMetadata_setTimeoutMillis,
+    k_AStatsManager_PullAtomMetadata_getTimeoutMillis,
+    k_AStatsManager_PullAtomMetadata_setAdditiveFields,
+    k_AStatsManager_PullAtomMetadata_getNumAdditiveFields,
+    k_AStatsManager_PullAtomMetadata_getAdditiveFields,
+
+    // AStatsEventList APIs in stats_pull_atom_callback.h
+    k_AStatsEventList_addStatsEvent,
+
+    // PullAtomCallback APIs in stats_pull_atom_callback.h
+    k_AStatsManager_setPullAtomCallback,
+    k_AStatsManager_clearPullAtomCallback,
+
+    // Marker for count of methods
+    k_MethodCount
+};
+
+// Table of methods pointers in libstatspull APIs.
+static void* g_Methods[k_MethodCount];
+
+//
+// Libstatspull lazy loading.
+//
+
+static atomic_bool gPreventLibstatspullLoading = false;  // Allows tests to block loading.
+
+void PreventLibstatspullLazyLoadingForTests() {
+    gPreventLibstatspullLoading.store(true);
+}
+
+static void* LoadLibstatspull(int dlopen_flags) {
+    if (gPreventLibstatspullLoading.load()) {
+        return nullptr;
+    }
+    return dlopen("libstatspull.so", dlopen_flags);
+}
+
+//
+// Initialization and symbol binding.
+
+static void BindSymbol(void* handle, const char* name, enum MethodIndex index) {
+    void* symbol = dlsym(handle, name);
+    LOG_ALWAYS_FATAL_IF(symbol == nullptr, "Failed to find symbol '%s' in libstatspull.so: %s",
+                        name, dlerror());
+    g_Methods[index] = symbol;
+}
+
+static void InitializeOnce() {
+    void* handle = LoadLibstatspull(RTLD_NOW);
+    LOG_ALWAYS_FATAL_IF(handle == nullptr, "Failed to load libstatspull.so: %s", dlerror());
+
+#undef BIND_SYMBOL
+#define BIND_SYMBOL(name) BindSymbol(handle, #name, k_##name);
+    // PullAtomMetadata APIs in stats_pull_atom_callback.h.
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_obtain);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_release);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_setCoolDownMillis);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_getCoolDownMillis);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_setTimeoutMillis);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_getTimeoutMillis);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_setAdditiveFields);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_getNumAdditiveFields);
+    BIND_SYMBOL(AStatsManager_PullAtomMetadata_getAdditiveFields);
+
+    // AStatsEventList APIs in stats_pull_atom_callback.h
+    BIND_SYMBOL(AStatsEventList_addStatsEvent);
+
+    // PullAtomCallback APIs in stats_pull_atom_callback.h
+    BIND_SYMBOL(AStatsManager_setPullAtomCallback);
+    BIND_SYMBOL(AStatsManager_clearPullAtomCallback);
+
+#undef BIND_SYMBOL
+
+    // Check every symbol is bound.
+    for (int i = 0; i < k_MethodCount; ++i) {
+        LOG_ALWAYS_FATAL_IF(g_Methods[i] == nullptr,
+                            "Uninitialized method in libstatspull_lazy at index: %d", i);
+    }
+}
+
+static void EnsureInitialized() {
+    static std::once_flag initialize_flag;
+    std::call_once(initialize_flag, InitializeOnce);
+}
+
+#define INVOKE_METHOD(name, args...)                            \
+    do {                                                        \
+        EnsureInitialized();                                    \
+        void* method = g_Methods[k_##name];                     \
+        return reinterpret_cast<decltype(&name)>(method)(args); \
+    } while (0)
+
+//
+// Forwarding for methods in stats_pull_atom_callback.h.
+//
+
+AStatsManager_PullAtomMetadata* AStatsManager_PullAtomMetadata_obtain() {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_obtain);
+}
+
+void AStatsManager_PullAtomMetadata_release(AStatsManager_PullAtomMetadata* metadata) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_release, metadata);
+}
+
+void AStatsManager_PullAtomMetadata_setCoolDownMillis(AStatsManager_PullAtomMetadata* metadata,
+                                                      int64_t cool_down_millis) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_setCoolDownMillis, metadata, cool_down_millis);
+}
+
+int64_t AStatsManager_PullAtomMetadata_getCoolDownMillis(AStatsManager_PullAtomMetadata* metadata) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_getCoolDownMillis, metadata);
+}
+
+void AStatsManager_PullAtomMetadata_setTimeoutMillis(AStatsManager_PullAtomMetadata* metadata,
+                                                     int64_t timeout_millis) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_setTimeoutMillis, metadata, timeout_millis);
+}
+
+int64_t AStatsManager_PullAtomMetadata_getTimeoutMillis(AStatsManager_PullAtomMetadata* metadata) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_getTimeoutMillis, metadata);
+}
+
+void AStatsManager_PullAtomMetadata_setAdditiveFields(AStatsManager_PullAtomMetadata* metadata,
+                                                      int32_t* additive_fields,
+                                                      int32_t num_fields) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_setAdditiveFields, metadata, additive_fields,
+                  num_fields);
+}
+
+int32_t AStatsManager_PullAtomMetadata_getNumAdditiveFields(
+        AStatsManager_PullAtomMetadata* metadata) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_getNumAdditiveFields, metadata);
+}
+
+void AStatsManager_PullAtomMetadata_getAdditiveFields(AStatsManager_PullAtomMetadata* metadata,
+                                                      int32_t* fields) {
+    INVOKE_METHOD(AStatsManager_PullAtomMetadata_getAdditiveFields, metadata, fields);
+}
+
+AStatsEvent* AStatsEventList_addStatsEvent(AStatsEventList* pull_data) {
+    INVOKE_METHOD(AStatsEventList_addStatsEvent, pull_data);
+}
+
+void AStatsManager_setPullAtomCallback(int32_t atom_tag, AStatsManager_PullAtomMetadata* metadata,
+                                       AStatsManager_PullAtomCallback callback, void* cookie) {
+    INVOKE_METHOD(AStatsManager_setPullAtomCallback, atom_tag, metadata, callback, cookie);
+}
+
+void AStatsManager_clearPullAtomCallback(int32_t atom_tag) {
+    INVOKE_METHOD(AStatsManager_clearPullAtomCallback, atom_tag);
+}