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| 1 /* | |
| 2 * Copyright 2004 The WebRTC Project Authors. All rights reserved. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license | |
| 5 * that can be found in the LICENSE file in the root of the source | |
| 6 * tree. An additional intellectual property rights grant can be found | |
| 7 * in the file PATENTS. All contributing project authors may | |
| 8 * be found in the AUTHORS file in the root of the source tree. | |
| 9 */ | |
| 10 | |
| 11 #include "webrtc/base/latebindingsymboltable.h" | |
| 12 | |
| 13 #if defined(WEBRTC_POSIX) | |
| 14 #include <dlfcn.h> | |
| 15 #endif | |
| 16 | |
| 17 #include "webrtc/base/logging.h" | |
| 18 | |
| 19 namespace rtc { | |
| 20 | |
| 21 #if defined(WEBRTC_POSIX) | |
| 22 static const DllHandle kInvalidDllHandle = NULL; | |
| 23 #else | |
| 24 #error Not implemented | |
| 25 #endif | |
| 26 | |
| 27 static const char *GetDllError() { | |
| 28 #if defined(WEBRTC_POSIX) | |
| 29 const char *err = dlerror(); | |
| 30 if (err) { | |
| 31 return err; | |
| 32 } else { | |
| 33 return "No error"; | |
| 34 } | |
| 35 #else | |
| 36 #error Not implemented | |
| 37 #endif | |
| 38 } | |
| 39 | |
| 40 static bool LoadSymbol(DllHandle handle, | |
| 41 const char *symbol_name, | |
| 42 void **symbol) { | |
| 43 #if defined(WEBRTC_POSIX) | |
| 44 *symbol = dlsym(handle, symbol_name); | |
| 45 const char *err = dlerror(); | |
| 46 if (err) { | |
| 47 LOG(LS_ERROR) << "Error loading symbol " << symbol_name << ": " << err; | |
| 48 return false; | |
| 49 } else if (!*symbol) { | |
| 50 // ELF allows for symbols to be NULL, but that should never happen for our | |
| 51 // usage. | |
| 52 LOG(LS_ERROR) << "Symbol " << symbol_name << " is NULL"; | |
| 53 return false; | |
| 54 } | |
| 55 return true; | |
| 56 #else | |
| 57 #error Not implemented | |
| 58 #endif | |
| 59 } | |
| 60 | |
| 61 LateBindingSymbolTable::LateBindingSymbolTable(const TableInfo *info, | |
| 62 void **table) | |
| 63 : info_(info), | |
| 64 table_(table), | |
| 65 handle_(kInvalidDllHandle), | |
| 66 undefined_symbols_(false) { | |
| 67 ClearSymbols(); | |
| 68 } | |
| 69 | |
| 70 LateBindingSymbolTable::~LateBindingSymbolTable() { | |
| 71 Unload(); | |
| 72 } | |
| 73 | |
| 74 bool LateBindingSymbolTable::IsLoaded() const { | |
| 75 return handle_ != kInvalidDllHandle; | |
| 76 } | |
| 77 | |
| 78 bool LateBindingSymbolTable::Load() { | |
| 79 ASSERT(info_->dll_name != NULL); | |
| 80 return LoadFromPath(info_->dll_name); | |
| 81 } | |
| 82 | |
| 83 bool LateBindingSymbolTable::LoadFromPath(const char *dll_path) { | |
| 84 if (IsLoaded()) { | |
| 85 return true; | |
| 86 } | |
| 87 if (undefined_symbols_) { | |
| 88 // We do not attempt to load again because repeated attempts are not | |
| 89 // likely to succeed and DLL loading is costly. | |
| 90 LOG(LS_ERROR) << "We know there are undefined symbols"; | |
| 91 return false; | |
| 92 } | |
| 93 | |
| 94 #if defined(WEBRTC_POSIX) | |
| 95 handle_ = dlopen(dll_path, | |
| 96 // RTLD_NOW front-loads symbol resolution so that errors are | |
| 97 // caught early instead of causing a process abort later. | |
| 98 // RTLD_LOCAL prevents other modules from automatically | |
| 99 // seeing symbol definitions in the newly-loaded tree. This | |
| 100 // is necessary for same-named symbols in different ABI | |
| 101 // versions of the same library to not explode. | |
| 102 RTLD_NOW|RTLD_LOCAL | |
| 103 #if defined(WEBRTC_LINUX) && !defined(WEBRTC_ANDROID) && defined(RTLD_DEEPBIND) | |
| 104 // RTLD_DEEPBIND makes symbol dependencies in the | |
| 105 // newly-loaded tree prefer to resolve to definitions within | |
| 106 // that tree (the default on OS X). This is necessary for | |
| 107 // same-named symbols in different ABI versions of the same | |
| 108 // library to not explode. | |
| 109 |RTLD_DEEPBIND | |
| 110 #endif | |
| 111 ); // NOLINT | |
| 112 #else | |
| 113 #error Not implemented | |
| 114 #endif | |
| 115 | |
| 116 if (handle_ == kInvalidDllHandle) { | |
| 117 LOG(LS_WARNING) << "Can't load " << dll_path << ": " | |
| 118 << GetDllError(); | |
| 119 return false; | |
| 120 } | |
| 121 #if defined(WEBRTC_POSIX) | |
| 122 // Clear any old errors. | |
| 123 dlerror(); | |
| 124 #endif | |
| 125 for (int i = 0; i < info_->num_symbols; ++i) { | |
| 126 if (!LoadSymbol(handle_, info_->symbol_names[i], &table_[i])) { | |
| 127 undefined_symbols_ = true; | |
| 128 Unload(); | |
| 129 return false; | |
| 130 } | |
| 131 } | |
| 132 return true; | |
| 133 } | |
| 134 | |
| 135 void LateBindingSymbolTable::Unload() { | |
| 136 if (!IsLoaded()) { | |
| 137 return; | |
| 138 } | |
| 139 | |
| 140 #if defined(WEBRTC_POSIX) | |
| 141 if (dlclose(handle_) != 0) { | |
| 142 LOG(LS_ERROR) << GetDllError(); | |
| 143 } | |
| 144 #else | |
| 145 #error Not implemented | |
| 146 #endif | |
| 147 | |
| 148 handle_ = kInvalidDllHandle; | |
| 149 ClearSymbols(); | |
| 150 } | |
| 151 | |
| 152 void LateBindingSymbolTable::ClearSymbols() { | |
| 153 memset(table_, 0, sizeof(void *) * info_->num_symbols); | |
| 154 } | |
| 155 | |
| 156 } // namespace rtc | |
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Chromium Code Reviews
Issue 2534593002:
Get rid of webrtc/base/latebindingsymboltable* (Closed)
