1 /*
2 * Copyright (C) 2021 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "libstatssocket_lazy.h"
18
19 #include <mutex>
20
21 #include <dlfcn.h>
22 #include <stdatomic.h>
23
24 #include "log/log.h"
25
26 #include "stats_event.h"
27 #include "stats_socket.h"
28
29 // This file provides a lazy interface to libstatssocket.so to address early boot dependencies.
30 // Specifically bootanimation, surfaceflinger, and lmkd run before the statsd APEX is loaded and
31 // libstatssocket.so is in the statsd APEX.
32
33 // Method pointers to libstatssocket methods are held in an array which simplifies checking
34 // all pointers are initialized.
35 enum MethodIndex {
36 // Stats Event APIs in stats_event.h.
37 k_AStatsEvent_obtain,
38 k_AStatsEvent_build,
39 k_AStatsEvent_write,
40 k_AStatsEvent_release,
41 k_AStatsEvent_setAtomId,
42 k_AStatsEvent_writeInt32,
43 k_AStatsEvent_writeInt64,
44 k_AStatsEvent_writeFloat,
45 k_AStatsEvent_writeBool,
46 k_AStatsEvent_writeByteArray,
47 k_AStatsEvent_writeString,
48 k_AStatsEvent_writeAttributionChain,
49 k_AStatsEvent_addBoolAnnotation,
50 k_AStatsEvent_addInt32Annotation,
51
52 // Stats Socket APIs in stats_socket.h.
53 k_AStatsSocket_close,
54
55 // Marker for count of methods
56 k_MethodCount
57 };
58
59 // Table of methods pointers in libstatssocket APIs.
60 static void* g_Methods[k_MethodCount];
61
62 //
63 // Libstatssocket lazy loading.
64 //
65
66 static atomic_bool gPreventLibstatssocketLoading = false; // Allows tests to block loading.
67
PreventLibstatssocketLazyLoadingForTests()68 void PreventLibstatssocketLazyLoadingForTests() {
69 gPreventLibstatssocketLoading.store(true);
70 }
71
LoadLibstatssocket(int dlopen_flags)72 static void* LoadLibstatssocket(int dlopen_flags) {
73 if (gPreventLibstatssocketLoading.load()) {
74 return nullptr;
75 }
76 return dlopen("libstatssocket.so", dlopen_flags);
77 }
78
79 //
80 // Initialization and symbol binding.
81
BindSymbol(void * handle,const char * name,enum MethodIndex index)82 static void BindSymbol(void* handle, const char* name, enum MethodIndex index) {
83 void* symbol = dlsym(handle, name);
84 LOG_ALWAYS_FATAL_IF(symbol == nullptr, "Failed to find symbol '%s' in libstatssocket.so: %s",
85 name, dlerror());
86 g_Methods[index] = symbol;
87 }
88
InitializeOnce()89 static void InitializeOnce() {
90 void* handle = LoadLibstatssocket(RTLD_NOW);
91 LOG_ALWAYS_FATAL_IF(handle == nullptr, "Failed to load libstatssocket.so: %s", dlerror());
92
93 #undef BIND_SYMBOL
94 #define BIND_SYMBOL(name) BindSymbol(handle, #name, k_##name);
95 // Methods in stats_event.h.
96 BIND_SYMBOL(AStatsEvent_obtain);
97 BIND_SYMBOL(AStatsEvent_build);
98 BIND_SYMBOL(AStatsEvent_write);
99 BIND_SYMBOL(AStatsEvent_release);
100 BIND_SYMBOL(AStatsEvent_setAtomId);
101 BIND_SYMBOL(AStatsEvent_writeInt32);
102 BIND_SYMBOL(AStatsEvent_writeInt64);
103 BIND_SYMBOL(AStatsEvent_writeFloat);
104 BIND_SYMBOL(AStatsEvent_writeBool);
105 BIND_SYMBOL(AStatsEvent_writeByteArray);
106 BIND_SYMBOL(AStatsEvent_writeString);
107 BIND_SYMBOL(AStatsEvent_writeAttributionChain);
108 BIND_SYMBOL(AStatsEvent_addBoolAnnotation);
109 BIND_SYMBOL(AStatsEvent_addInt32Annotation);
110
111 // Methods in stats_socket.h.
112 BIND_SYMBOL(AStatsSocket_close);
113 #undef BIND_SYMBOL
114
115 // Check every symbol is bound.
116 for (int i = 0; i < k_MethodCount; ++i) {
117 LOG_ALWAYS_FATAL_IF(g_Methods[i] == nullptr,
118 "Uninitialized method in libstatssocket_lazy at index: %d", i);
119 }
120 }
121
EnsureInitialized()122 static void EnsureInitialized() {
123 static std::once_flag initialize_flag;
124 std::call_once(initialize_flag, InitializeOnce);
125 }
126
127 #define INVOKE_METHOD(name, args...) \
128 do { \
129 EnsureInitialized(); \
130 void* method = g_Methods[k_##name]; \
131 return reinterpret_cast<decltype(&name)>(method)(args); \
132 } while (0)
133
134 //
135 // Forwarding for methods in stats_event.h.
136 //
137
AStatsEvent_obtain()138 AStatsEvent* AStatsEvent_obtain() {
139 INVOKE_METHOD(AStatsEvent_obtain);
140 }
141
AStatsEvent_build(AStatsEvent * event)142 void AStatsEvent_build(AStatsEvent* event) {
143 INVOKE_METHOD(AStatsEvent_build, event);
144 }
145
AStatsEvent_write(AStatsEvent * event)146 int AStatsEvent_write(AStatsEvent* event) {
147 INVOKE_METHOD(AStatsEvent_write, event);
148 }
149
AStatsEvent_release(AStatsEvent * event)150 void AStatsEvent_release(AStatsEvent* event) {
151 INVOKE_METHOD(AStatsEvent_release, event);
152 }
153
AStatsEvent_setAtomId(AStatsEvent * event,uint32_t atomId)154 void AStatsEvent_setAtomId(AStatsEvent* event, uint32_t atomId) {
155 INVOKE_METHOD(AStatsEvent_setAtomId, event, atomId);
156 }
157
AStatsEvent_writeInt32(AStatsEvent * event,int32_t value)158 void AStatsEvent_writeInt32(AStatsEvent* event, int32_t value) {
159 INVOKE_METHOD(AStatsEvent_writeInt32, event, value);
160 }
161
AStatsEvent_writeInt64(AStatsEvent * event,int64_t value)162 void AStatsEvent_writeInt64(AStatsEvent* event, int64_t value) {
163 INVOKE_METHOD(AStatsEvent_writeInt64, event, value);
164 }
165
AStatsEvent_writeFloat(AStatsEvent * event,float value)166 void AStatsEvent_writeFloat(AStatsEvent* event, float value) {
167 INVOKE_METHOD(AStatsEvent_writeFloat, event, value);
168 }
169
AStatsEvent_writeBool(AStatsEvent * event,bool value)170 void AStatsEvent_writeBool(AStatsEvent* event, bool value) {
171 INVOKE_METHOD(AStatsEvent_writeBool, event, value);
172 }
173
AStatsEvent_writeByteArray(AStatsEvent * event,const uint8_t * buf,size_t numBytes)174 void AStatsEvent_writeByteArray(AStatsEvent* event, const uint8_t* buf, size_t numBytes) {
175 INVOKE_METHOD(AStatsEvent_writeByteArray, event, buf, numBytes);
176 }
177
AStatsEvent_writeString(AStatsEvent * event,const char * value)178 void AStatsEvent_writeString(AStatsEvent* event, const char* value) {
179 INVOKE_METHOD(AStatsEvent_writeString, event, value);
180 }
181
AStatsEvent_writeAttributionChain(AStatsEvent * event,const uint32_t * uids,const char * const * tags,uint8_t numNodes)182 void AStatsEvent_writeAttributionChain(AStatsEvent* event, const uint32_t* uids,
183 const char* const* tags, uint8_t numNodes) {
184 INVOKE_METHOD(AStatsEvent_writeAttributionChain, event, uids, tags, numNodes);
185 }
186
AStatsEvent_addBoolAnnotation(AStatsEvent * event,uint8_t annotationId,bool value)187 void AStatsEvent_addBoolAnnotation(AStatsEvent* event, uint8_t annotationId, bool value) {
188 INVOKE_METHOD(AStatsEvent_addBoolAnnotation, event, annotationId, value);
189 }
190
AStatsEvent_addInt32Annotation(AStatsEvent * event,uint8_t annotationId,int32_t value)191 void AStatsEvent_addInt32Annotation(AStatsEvent* event, uint8_t annotationId, int32_t value) {
192 INVOKE_METHOD(AStatsEvent_addInt32Annotation, event, annotationId, value);
193 }
194
195 //
196 // Forwarding for methods in stats_socket.h.
197 //
198
AStatsSocket_close()199 void AStatsSocket_close() {
200 INVOKE_METHOD(AStatsSocket_close);
201 }