1 //===--------------------- ModuleCache.cpp ----------------------*- C++ -*-===// 2 // 3 // The LLVM Compiler Infrastructure 4 // 5 // This file is distributed under the University of Illinois Open Source 6 // License. See LICENSE.TXT for details. 7 // 8 //===----------------------------------------------------------------------===// 9 10 #include "lldb/Target/ModuleCache.h" 11 12 #include "lldb/Core/Module.h" 13 #include "lldb/Core/ModuleList.h" 14 #include "lldb/Core/ModuleSpec.h" 15 #include "lldb/Host/File.h" 16 #include "lldb/Host/FileSystem.h" 17 #include "lldb/Host/LockFile.h" 18 #include "lldb/Utility/Log.h" 19 #include "llvm/Support/FileSystem.h" 20 #include "llvm/Support/FileUtilities.h" 21 22 #include <assert.h> 23 24 #include <cstdio> 25 26 using namespace lldb; 27 using namespace lldb_private; 28 29 namespace { 30 31 const char *kModulesSubdir = ".cache"; 32 const char *kLockDirName = ".lock"; 33 const char *kTempFileName = ".temp"; 34 const char *kTempSymFileName = ".symtemp"; 35 const char *kSymFileExtension = ".sym"; 36 const char *kFSIllegalChars = "\\/:*?\"<>|"; 37 38 std::string GetEscapedHostname(const char *hostname) { 39 if (hostname == nullptr) 40 hostname = "unknown"; 41 std::string result(hostname); 42 size_t size = result.size(); 43 for (size_t i = 0; i < size; ++i) { 44 if ((result[i] >= 1 && result[i] <= 31) || 45 strchr(kFSIllegalChars, result[i]) != nullptr) 46 result[i] = '_'; 47 } 48 return result; 49 } 50 51 class ModuleLock { 52 private: 53 File m_file; 54 std::unique_ptr<lldb_private::LockFile> m_lock; 55 FileSpec m_file_spec; 56 57 public: 58 ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid, Error &error); 59 void Delete(); 60 }; 61 62 static FileSpec JoinPath(const FileSpec &path1, const char *path2) { 63 FileSpec result_spec(path1); 64 result_spec.AppendPathComponent(path2); 65 return result_spec; 66 } 67 68 static Error MakeDirectory(const FileSpec &dir_path) { 69 namespace fs = llvm::sys::fs; 70 71 return fs::create_directories(dir_path.GetPath(), true, fs::perms::owner_all); 72 } 73 74 FileSpec GetModuleDirectory(const FileSpec &root_dir_spec, const UUID &uuid) { 75 const auto modules_dir_spec = JoinPath(root_dir_spec, kModulesSubdir); 76 return JoinPath(modules_dir_spec, uuid.GetAsString().c_str()); 77 } 78 79 FileSpec GetSymbolFileSpec(const FileSpec &module_file_spec) { 80 return FileSpec(module_file_spec.GetPath() + kSymFileExtension, false); 81 } 82 83 void DeleteExistingModule(const FileSpec &root_dir_spec, 84 const FileSpec &sysroot_module_path_spec) { 85 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES)); 86 UUID module_uuid; 87 { 88 auto module_sp = 89 std::make_shared<Module>(ModuleSpec(sysroot_module_path_spec)); 90 module_uuid = module_sp->GetUUID(); 91 } 92 93 if (!module_uuid.IsValid()) 94 return; 95 96 Error error; 97 ModuleLock lock(root_dir_spec, module_uuid, error); 98 if (error.Fail()) { 99 if (log) 100 log->Printf("Failed to lock module %s: %s", 101 module_uuid.GetAsString().c_str(), error.AsCString()); 102 } 103 104 auto link_count = FileSystem::GetHardlinkCount(sysroot_module_path_spec); 105 if (link_count == -1) 106 return; 107 108 if (link_count > 2) // module is referred by other hosts. 109 return; 110 111 const auto module_spec_dir = GetModuleDirectory(root_dir_spec, module_uuid); 112 llvm::sys::fs::remove_directories(module_spec_dir.GetPath()); 113 lock.Delete(); 114 } 115 116 void DecrementRefExistingModule(const FileSpec &root_dir_spec, 117 const FileSpec &sysroot_module_path_spec) { 118 // Remove $platform/.cache/$uuid folder if nobody else references it. 119 DeleteExistingModule(root_dir_spec, sysroot_module_path_spec); 120 121 // Remove sysroot link. 122 FileSystem::Unlink(sysroot_module_path_spec); 123 124 FileSpec symfile_spec = GetSymbolFileSpec(sysroot_module_path_spec); 125 if (symfile_spec.Exists()) // delete module's symbol file if exists. 126 FileSystem::Unlink(symfile_spec); 127 } 128 129 Error CreateHostSysRootModuleLink(const FileSpec &root_dir_spec, 130 const char *hostname, 131 const FileSpec &platform_module_spec, 132 const FileSpec &local_module_spec, 133 bool delete_existing) { 134 const auto sysroot_module_path_spec = 135 JoinPath(JoinPath(root_dir_spec, hostname), 136 platform_module_spec.GetPath().c_str()); 137 if (sysroot_module_path_spec.Exists()) { 138 if (!delete_existing) 139 return Error(); 140 141 DecrementRefExistingModule(root_dir_spec, sysroot_module_path_spec); 142 } 143 144 const auto error = MakeDirectory( 145 FileSpec(sysroot_module_path_spec.GetDirectory().AsCString(), false)); 146 if (error.Fail()) 147 return error; 148 149 return FileSystem::Hardlink(sysroot_module_path_spec, local_module_spec); 150 } 151 152 } // namespace 153 154 ModuleLock::ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid, 155 Error &error) { 156 const auto lock_dir_spec = JoinPath(root_dir_spec, kLockDirName); 157 error = MakeDirectory(lock_dir_spec); 158 if (error.Fail()) 159 return; 160 161 m_file_spec = JoinPath(lock_dir_spec, uuid.GetAsString().c_str()); 162 m_file.Open(m_file_spec.GetCString(), File::eOpenOptionWrite | 163 File::eOpenOptionCanCreate | 164 File::eOpenOptionCloseOnExec); 165 if (!m_file) { 166 error.SetErrorToErrno(); 167 return; 168 } 169 170 m_lock.reset(new lldb_private::LockFile(m_file.GetDescriptor())); 171 error = m_lock->WriteLock(0, 1); 172 if (error.Fail()) 173 error.SetErrorStringWithFormat("Failed to lock file: %s", 174 error.AsCString()); 175 } 176 177 void ModuleLock::Delete() { 178 if (!m_file) 179 return; 180 181 m_file.Close(); 182 FileSystem::Unlink(m_file_spec); 183 } 184 185 ///////////////////////////////////////////////////////////////////////// 186 187 Error ModuleCache::Put(const FileSpec &root_dir_spec, const char *hostname, 188 const ModuleSpec &module_spec, const FileSpec &tmp_file, 189 const FileSpec &target_file) { 190 const auto module_spec_dir = 191 GetModuleDirectory(root_dir_spec, module_spec.GetUUID()); 192 const auto module_file_path = 193 JoinPath(module_spec_dir, target_file.GetFilename().AsCString()); 194 195 const auto tmp_file_path = tmp_file.GetPath(); 196 const auto err_code = 197 llvm::sys::fs::rename(tmp_file_path, module_file_path.GetPath()); 198 if (err_code) 199 return Error("Failed to rename file %s to %s: %s", tmp_file_path.c_str(), 200 module_file_path.GetPath().c_str(), 201 err_code.message().c_str()); 202 203 const auto error = CreateHostSysRootModuleLink( 204 root_dir_spec, hostname, target_file, module_file_path, true); 205 if (error.Fail()) 206 return Error("Failed to create link to %s: %s", 207 module_file_path.GetPath().c_str(), error.AsCString()); 208 return Error(); 209 } 210 211 Error ModuleCache::Get(const FileSpec &root_dir_spec, const char *hostname, 212 const ModuleSpec &module_spec, 213 ModuleSP &cached_module_sp, bool *did_create_ptr) { 214 const auto find_it = 215 m_loaded_modules.find(module_spec.GetUUID().GetAsString()); 216 if (find_it != m_loaded_modules.end()) { 217 cached_module_sp = (*find_it).second.lock(); 218 if (cached_module_sp) 219 return Error(); 220 m_loaded_modules.erase(find_it); 221 } 222 223 const auto module_spec_dir = 224 GetModuleDirectory(root_dir_spec, module_spec.GetUUID()); 225 const auto module_file_path = JoinPath( 226 module_spec_dir, module_spec.GetFileSpec().GetFilename().AsCString()); 227 228 if (!module_file_path.Exists()) 229 return Error("Module %s not found", module_file_path.GetPath().c_str()); 230 if (module_file_path.GetByteSize() != module_spec.GetObjectSize()) 231 return Error("Module %s has invalid file size", 232 module_file_path.GetPath().c_str()); 233 234 // We may have already cached module but downloaded from an another host - in 235 // this case let's create a link to it. 236 auto error = CreateHostSysRootModuleLink(root_dir_spec, hostname, 237 module_spec.GetFileSpec(), 238 module_file_path, false); 239 if (error.Fail()) 240 return Error("Failed to create link to %s: %s", 241 module_file_path.GetPath().c_str(), error.AsCString()); 242 243 auto cached_module_spec(module_spec); 244 cached_module_spec.GetUUID().Clear(); // Clear UUID since it may contain md5 245 // content hash instead of real UUID. 246 cached_module_spec.GetFileSpec() = module_file_path; 247 cached_module_spec.GetPlatformFileSpec() = module_spec.GetFileSpec(); 248 249 error = ModuleList::GetSharedModule(cached_module_spec, cached_module_sp, 250 nullptr, nullptr, did_create_ptr, false); 251 if (error.Fail()) 252 return error; 253 254 FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec()); 255 if (symfile_spec.Exists()) 256 cached_module_sp->SetSymbolFileFileSpec(symfile_spec); 257 258 m_loaded_modules.insert( 259 std::make_pair(module_spec.GetUUID().GetAsString(), cached_module_sp)); 260 261 return Error(); 262 } 263 264 Error ModuleCache::GetAndPut(const FileSpec &root_dir_spec, 265 const char *hostname, 266 const ModuleSpec &module_spec, 267 const ModuleDownloader &module_downloader, 268 const SymfileDownloader &symfile_downloader, 269 lldb::ModuleSP &cached_module_sp, 270 bool *did_create_ptr) { 271 const auto module_spec_dir = 272 GetModuleDirectory(root_dir_spec, module_spec.GetUUID()); 273 auto error = MakeDirectory(module_spec_dir); 274 if (error.Fail()) 275 return error; 276 277 ModuleLock lock(root_dir_spec, module_spec.GetUUID(), error); 278 if (error.Fail()) 279 return Error("Failed to lock module %s: %s", 280 module_spec.GetUUID().GetAsString().c_str(), 281 error.AsCString()); 282 283 const auto escaped_hostname(GetEscapedHostname(hostname)); 284 // Check local cache for a module. 285 error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec, 286 cached_module_sp, did_create_ptr); 287 if (error.Success()) 288 return error; 289 290 const auto tmp_download_file_spec = JoinPath(module_spec_dir, kTempFileName); 291 error = module_downloader(module_spec, tmp_download_file_spec); 292 llvm::FileRemover tmp_file_remover(tmp_download_file_spec.GetPath()); 293 if (error.Fail()) 294 return Error("Failed to download module: %s", error.AsCString()); 295 296 // Put downloaded file into local module cache. 297 error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec, 298 tmp_download_file_spec, module_spec.GetFileSpec()); 299 if (error.Fail()) 300 return Error("Failed to put module into cache: %s", error.AsCString()); 301 302 tmp_file_remover.releaseFile(); 303 error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec, 304 cached_module_sp, did_create_ptr); 305 if (error.Fail()) 306 return error; 307 308 // Fetching a symbol file for the module 309 const auto tmp_download_sym_file_spec = 310 JoinPath(module_spec_dir, kTempSymFileName); 311 error = symfile_downloader(cached_module_sp, tmp_download_sym_file_spec); 312 llvm::FileRemover tmp_symfile_remover(tmp_download_sym_file_spec.GetPath()); 313 if (error.Fail()) 314 // Failed to download a symfile but fetching the module was successful. The 315 // module might 316 // contain the necessary symbols and the debugging is also possible without 317 // a symfile. 318 return Error(); 319 320 error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec, 321 tmp_download_sym_file_spec, 322 GetSymbolFileSpec(module_spec.GetFileSpec())); 323 if (error.Fail()) 324 return Error("Failed to put symbol file into cache: %s", error.AsCString()); 325 326 tmp_symfile_remover.releaseFile(); 327 328 FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec()); 329 cached_module_sp->SetSymbolFileFileSpec(symfile_spec); 330 return Error(); 331 } 332