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1 /*
2  * Copyright (C) 2016 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 #define LOG_TAG "HidlInternal"
18 
19 #include <hidl/HidlInternal.h>
20 
21 #include <android-base/logging.h>
22 #include <android-base/properties.h>
23 #include <android-base/stringprintf.h>
24 #include <cutils/properties.h>
25 
26 #ifdef LIBHIDL_TARGET_DEBUGGABLE
27 #include <dirent.h>
28 #include <dlfcn.h>
29 #include <link.h>
30 #include <utils/misc.h>
31 #include <regex>
32 
33 extern "C" __attribute__((weak)) void __sanitizer_cov_dump();
34 
35 const char kGcovPrefixEnvVar[] = "GCOV_PREFIX";
36 const char kGcovPrefixOverrideEnvVar[] = "GCOV_PREFIX_OVERRIDE";
37 const char kGcovPrefixPath[] = "/data/misc/trace/";
38 const char kSysPropHalCoverage[] = "hal.coverage.enable";
39 #if defined(__LP64__)
40 const char kSysPropInstrumentationPath[] = "hal.instrumentation.lib.path.64";
41 #else
42 const char kSysPropInstrumentationPath[] = "hal.instrumentation.lib.path.32";
43 #endif
44 #endif  // LIBHIDL_TARGET_DEBUGGABLE
45 
46 namespace android {
47 namespace hardware {
48 namespace details {
49 
logAlwaysFatal(const char * message)50 void logAlwaysFatal(const char* message) {
51     LOG(FATAL) << message;
52 }
53 
getVndkVersionStr()54 std::string getVndkVersionStr() {
55     static std::string vndkVersion("0");
56     // "0" means the vndkVersion must be initialized with the property value.
57     // Otherwise, return the value.
58     if (vndkVersion == "0") {
59         vndkVersion = android::base::GetProperty("ro.vndk.version", "");
60         if (vndkVersion != "" && vndkVersion != "current") {
61             vndkVersion = "-" + vndkVersion;
62         } else {
63             vndkVersion = "";
64         }
65     }
66     return vndkVersion;
67 }
68 
69 // ----------------------------------------------------------------------
70 // HidlInstrumentor implementation.
HidlInstrumentor(const std::string & package,const std::string & interface)71 HidlInstrumentor::HidlInstrumentor(const std::string& package, const std::string& interface)
72     : mEnableInstrumentation(false),
73       mInstrumentationLibPackage(package),
74       mInterfaceName(interface) {
75 #ifdef LIBHIDL_TARGET_DEBUGGABLE
76     configureInstrumentation(false);
77     if (__sanitizer_cov_dump != nullptr) {
78         ::android::add_sysprop_change_callback(
79             []() {
80                 bool enableCoverage = property_get_bool(kSysPropHalCoverage, false);
81                 if (enableCoverage) {
82                     __sanitizer_cov_dump();
83                 }
84             },
85             0);
86     }
87     if (property_get_bool("ro.vts.coverage", false)) {
88         const char* prefixOverride = getenv(kGcovPrefixOverrideEnvVar);
89         if (prefixOverride == nullptr || strcmp(prefixOverride, "true") != 0) {
90             const std::string gcovPath = kGcovPrefixPath + std::to_string(getpid());
91             setenv(kGcovPrefixEnvVar, gcovPath.c_str(), true /* overwrite */);
92         }
93         ::android::add_sysprop_change_callback(
94             []() {
95                 const bool enableCoverage = property_get_bool(kSysPropHalCoverage, false);
96                 if (enableCoverage) {
97                     dl_iterate_phdr(
98                         [](struct dl_phdr_info* info, size_t /* size */, void* /* data */) {
99                             if (strlen(info->dlpi_name) == 0) return 0;
100 
101                             void* handle = dlopen(info->dlpi_name, RTLD_LAZY);
102                             if (handle == nullptr) {
103                                 LOG(INFO) << "coverage dlopen failed: " << dlerror();
104                                 return 0;
105                             }
106                             void (*flush)() = (void (*)())dlsym(handle, "__gcov_flush");
107                             if (flush == nullptr) {
108                                 return 0;
109                             }
110                             flush();
111                             return 0;
112                         },
113                         nullptr /* data */);
114                 }
115             },
116             0 /* priority */);
117     }
118 #endif
119 }
120 
~HidlInstrumentor()121 HidlInstrumentor::~HidlInstrumentor() {}
122 
configureInstrumentation(bool log)123 void HidlInstrumentor::configureInstrumentation(bool log) {
124     mEnableInstrumentation = property_get_bool("hal.instrumentation.enable", false);
125     if (mEnableInstrumentation) {
126         if (log) {
127             LOG(INFO) << "Enable instrumentation.";
128         }
129         mInstrumentationCallbacks.clear();
130         registerInstrumentationCallbacks(&mInstrumentationCallbacks);
131     } else {
132         if (log) {
133             LOG(INFO) << "Disable instrumentation.";
134         }
135         mInstrumentationCallbacks.clear();
136     }
137 }
138 
registerInstrumentationCallbacks(std::vector<InstrumentationCallback> * instrumentationCallbacks)139 void HidlInstrumentor::registerInstrumentationCallbacks(
140         std::vector<InstrumentationCallback> *instrumentationCallbacks) {
141 #ifdef LIBHIDL_TARGET_DEBUGGABLE
142     std::vector<std::string> instrumentationLibPaths;
143     char instrumentationLibPath[PROPERTY_VALUE_MAX];
144     if (property_get(kSysPropInstrumentationPath, instrumentationLibPath, "") > 0) {
145         instrumentationLibPaths.push_back(instrumentationLibPath);
146     } else {
147         static std::string halLibPathVndkSp = android::base::StringPrintf(
148             HAL_LIBRARY_PATH_VNDK_SP_FOR_VERSION, getVndkVersionStr().c_str());
149 #ifndef __ANDROID_VNDK__
150         instrumentationLibPaths.push_back(HAL_LIBRARY_PATH_SYSTEM);
151 #endif
152         instrumentationLibPaths.push_back(halLibPathVndkSp);
153         instrumentationLibPaths.push_back(HAL_LIBRARY_PATH_VENDOR);
154         instrumentationLibPaths.push_back(HAL_LIBRARY_PATH_ODM);
155     }
156 
157     for (const auto& path : instrumentationLibPaths) {
158         DIR *dir = opendir(path.c_str());
159         if (dir == nullptr) {
160             LOG(WARNING) << path << " does not exist. ";
161             return;
162         }
163 
164         struct dirent *file;
165         while ((file = readdir(dir)) != nullptr) {
166             if (!isInstrumentationLib(file))
167                 continue;
168 
169             void *handle = dlopen((path + file->d_name).c_str(), RTLD_NOW);
170             char *error;
171             if (handle == nullptr) {
172                 LOG(WARNING) << "couldn't load file: " << file->d_name
173                     << " error: " << dlerror();
174                 continue;
175             }
176 
177             dlerror(); /* Clear any existing error */
178 
179             using cbFun = void (*)(
180                     const InstrumentationEvent,
181                     const char *,
182                     const char *,
183                     const char *,
184                     const char *,
185                     std::vector<void *> *);
186             std::string package = mInstrumentationLibPackage;
187             for (size_t i = 0; i < package.size(); i++) {
188                 if (package[i] == '.') {
189                     package[i] = '_';
190                     continue;
191                 }
192 
193                 if (package[i] == '@') {
194                     package[i] = '_';
195                     package.insert(i + 1, "V");
196                     continue;
197                 }
198             }
199             auto cb = (cbFun)dlsym(handle, ("HIDL_INSTRUMENTATION_FUNCTION_"
200                         + package + "_" + mInterfaceName).c_str());
201             if ((error = dlerror()) != nullptr) {
202                 LOG(WARNING)
203                     << "couldn't find symbol: HIDL_INSTRUMENTATION_FUNCTION_"
204                     << package << "_" << mInterfaceName << ", error: " << error;
205                 continue;
206             }
207             instrumentationCallbacks->push_back(cb);
208             LOG(INFO) << "Register instrumentation callback from "
209                 << file->d_name;
210         }
211         closedir(dir);
212     }
213 #else
214     // No-op for user builds.
215     (void) instrumentationCallbacks;
216     return;
217 #endif
218 }
219 
isInstrumentationLib(const dirent * file)220 bool HidlInstrumentor::isInstrumentationLib(const dirent *file) {
221 #ifdef LIBHIDL_TARGET_DEBUGGABLE
222     if (file->d_type != DT_REG) return false;
223     std::cmatch cm;
224     std::regex e("^" + mInstrumentationLibPackage + "(.*).profiler.so$");
225     if (std::regex_match(file->d_name, cm, e)) return true;
226 #else
227     (void) file;
228 #endif
229     return false;
230 }
231 
232 }  // namespace details
233 }  // namespace hardware
234 }  // namespace android
235