1 //===--------------------- ModuleCache.cpp ----------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #include "lldb/Target/ModuleCache.h" 10 11 #include "lldb/Core/Module.h" 12 #include "lldb/Core/ModuleList.h" 13 #include "lldb/Core/ModuleSpec.h" 14 #include "lldb/Host/File.h" 15 #include "lldb/Host/LockFile.h" 16 #include "lldb/Utility/Log.h" 17 #include "llvm/Support/FileSystem.h" 18 #include "llvm/Support/FileUtilities.h" 19 20 #include <assert.h> 21 22 #include <cstdio> 23 24 using namespace lldb; 25 using namespace lldb_private; 26 27 namespace { 28 29 const char *kModulesSubdir = ".cache"; 30 const char *kLockDirName = ".lock"; 31 const char *kTempFileName = ".temp"; 32 const char *kTempSymFileName = ".symtemp"; 33 const char *kSymFileExtension = ".sym"; 34 const char *kFSIllegalChars = "\\/:*?\"<>|"; 35 36 std::string GetEscapedHostname(const char *hostname) { 37 if (hostname == nullptr) 38 hostname = "unknown"; 39 std::string result(hostname); 40 size_t size = result.size(); 41 for (size_t i = 0; i < size; ++i) { 42 if ((result[i] >= 1 && result[i] <= 31) || 43 strchr(kFSIllegalChars, result[i]) != nullptr) 44 result[i] = '_'; 45 } 46 return result; 47 } 48 49 class ModuleLock { 50 private: 51 File m_file; 52 std::unique_ptr<lldb_private::LockFile> m_lock; 53 FileSpec m_file_spec; 54 55 public: 56 ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid, Status &error); 57 void Delete(); 58 }; 59 60 static FileSpec JoinPath(const FileSpec &path1, const char *path2) { 61 FileSpec result_spec(path1); 62 result_spec.AppendPathComponent(path2); 63 return result_spec; 64 } 65 66 static Status MakeDirectory(const FileSpec &dir_path) { 67 namespace fs = llvm::sys::fs; 68 69 return fs::create_directories(dir_path.GetPath(), true, fs::perms::owner_all); 70 } 71 72 FileSpec GetModuleDirectory(const FileSpec &root_dir_spec, const UUID &uuid) { 73 const auto modules_dir_spec = JoinPath(root_dir_spec, kModulesSubdir); 74 return JoinPath(modules_dir_spec, uuid.GetAsString().c_str()); 75 } 76 77 FileSpec GetSymbolFileSpec(const FileSpec &module_file_spec) { 78 return FileSpec(module_file_spec.GetPath() + kSymFileExtension); 79 } 80 81 void DeleteExistingModule(const FileSpec &root_dir_spec, 82 const FileSpec &sysroot_module_path_spec) { 83 Log *log(GetLogIfAllCategoriesSet(LIBLLDB_LOG_MODULES)); 84 UUID module_uuid; 85 { 86 auto module_sp = 87 std::make_shared<Module>(ModuleSpec(sysroot_module_path_spec)); 88 module_uuid = module_sp->GetUUID(); 89 } 90 91 if (!module_uuid.IsValid()) 92 return; 93 94 Status error; 95 ModuleLock lock(root_dir_spec, module_uuid, error); 96 if (error.Fail()) { 97 if (log) 98 log->Printf("Failed to lock module %s: %s", 99 module_uuid.GetAsString().c_str(), error.AsCString()); 100 } 101 102 namespace fs = llvm::sys::fs; 103 fs::file_status st; 104 if (status(sysroot_module_path_spec.GetPath(), st)) 105 return; 106 107 if (st.getLinkCount() > 2) // module is referred by other hosts. 108 return; 109 110 const auto module_spec_dir = GetModuleDirectory(root_dir_spec, module_uuid); 111 llvm::sys::fs::remove_directories(module_spec_dir.GetPath()); 112 lock.Delete(); 113 } 114 115 void DecrementRefExistingModule(const FileSpec &root_dir_spec, 116 const FileSpec &sysroot_module_path_spec) { 117 // Remove $platform/.cache/$uuid folder if nobody else references it. 118 DeleteExistingModule(root_dir_spec, sysroot_module_path_spec); 119 120 // Remove sysroot link. 121 llvm::sys::fs::remove(sysroot_module_path_spec.GetPath()); 122 123 FileSpec symfile_spec = GetSymbolFileSpec(sysroot_module_path_spec); 124 llvm::sys::fs::remove(symfile_spec.GetPath()); 125 } 126 127 Status CreateHostSysRootModuleLink(const FileSpec &root_dir_spec, 128 const char *hostname, 129 const FileSpec &platform_module_spec, 130 const FileSpec &local_module_spec, 131 bool delete_existing) { 132 const auto sysroot_module_path_spec = 133 JoinPath(JoinPath(root_dir_spec, hostname), 134 platform_module_spec.GetPath().c_str()); 135 if (FileSystem::Instance().Exists(sysroot_module_path_spec)) { 136 if (!delete_existing) 137 return Status(); 138 139 DecrementRefExistingModule(root_dir_spec, sysroot_module_path_spec); 140 } 141 142 const auto error = MakeDirectory( 143 FileSpec(sysroot_module_path_spec.GetDirectory().AsCString())); 144 if (error.Fail()) 145 return error; 146 147 return llvm::sys::fs::create_hard_link(local_module_spec.GetPath(), 148 sysroot_module_path_spec.GetPath()); 149 } 150 151 } // namespace 152 153 ModuleLock::ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid, 154 Status &error) { 155 const auto lock_dir_spec = JoinPath(root_dir_spec, kLockDirName); 156 error = MakeDirectory(lock_dir_spec); 157 if (error.Fail()) 158 return; 159 160 m_file_spec = JoinPath(lock_dir_spec, uuid.GetAsString().c_str()); 161 FileSystem::Instance().Open(m_file, m_file_spec, 162 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 llvm::sys::fs::remove(m_file_spec.GetPath()); 183 } 184 185 ///////////////////////////////////////////////////////////////////////// 186 187 Status 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 Status("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 Status("Failed to create link to %s: %s", 207 module_file_path.GetPath().c_str(), error.AsCString()); 208 return Status(); 209 } 210 211 Status 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 Status(); 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 (!FileSystem::Instance().Exists(module_file_path)) 229 return Status("Module %s not found", module_file_path.GetPath().c_str()); 230 if (FileSystem::Instance().GetByteSize(module_file_path) != 231 module_spec.GetObjectSize()) 232 return Status("Module %s has invalid file size", 233 module_file_path.GetPath().c_str()); 234 235 // We may have already cached module but downloaded from an another host - in 236 // this case let's create a link to it. 237 auto error = CreateHostSysRootModuleLink(root_dir_spec, hostname, 238 module_spec.GetFileSpec(), 239 module_file_path, false); 240 if (error.Fail()) 241 return Status("Failed to create link to %s: %s", 242 module_file_path.GetPath().c_str(), error.AsCString()); 243 244 auto cached_module_spec(module_spec); 245 cached_module_spec.GetUUID().Clear(); // Clear UUID since it may contain md5 246 // content hash instead of real UUID. 247 cached_module_spec.GetFileSpec() = module_file_path; 248 cached_module_spec.GetPlatformFileSpec() = module_spec.GetFileSpec(); 249 250 error = ModuleList::GetSharedModule(cached_module_spec, cached_module_sp, 251 nullptr, nullptr, did_create_ptr, false); 252 if (error.Fail()) 253 return error; 254 255 FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec()); 256 if (FileSystem::Instance().Exists(symfile_spec)) 257 cached_module_sp->SetSymbolFileFileSpec(symfile_spec); 258 259 m_loaded_modules.insert( 260 std::make_pair(module_spec.GetUUID().GetAsString(), cached_module_sp)); 261 262 return Status(); 263 } 264 265 Status ModuleCache::GetAndPut(const FileSpec &root_dir_spec, 266 const char *hostname, 267 const ModuleSpec &module_spec, 268 const ModuleDownloader &module_downloader, 269 const SymfileDownloader &symfile_downloader, 270 lldb::ModuleSP &cached_module_sp, 271 bool *did_create_ptr) { 272 const auto module_spec_dir = 273 GetModuleDirectory(root_dir_spec, module_spec.GetUUID()); 274 auto error = MakeDirectory(module_spec_dir); 275 if (error.Fail()) 276 return error; 277 278 ModuleLock lock(root_dir_spec, module_spec.GetUUID(), error); 279 if (error.Fail()) 280 return Status("Failed to lock module %s: %s", 281 module_spec.GetUUID().GetAsString().c_str(), 282 error.AsCString()); 283 284 const auto escaped_hostname(GetEscapedHostname(hostname)); 285 // Check local cache for a module. 286 error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec, 287 cached_module_sp, did_create_ptr); 288 if (error.Success()) 289 return error; 290 291 const auto tmp_download_file_spec = JoinPath(module_spec_dir, kTempFileName); 292 error = module_downloader(module_spec, tmp_download_file_spec); 293 llvm::FileRemover tmp_file_remover(tmp_download_file_spec.GetPath()); 294 if (error.Fail()) 295 return Status("Failed to download module: %s", error.AsCString()); 296 297 // Put downloaded file into local module cache. 298 error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec, 299 tmp_download_file_spec, module_spec.GetFileSpec()); 300 if (error.Fail()) 301 return Status("Failed to put module into cache: %s", error.AsCString()); 302 303 tmp_file_remover.releaseFile(); 304 error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec, 305 cached_module_sp, did_create_ptr); 306 if (error.Fail()) 307 return error; 308 309 // Fetching a symbol file for the module 310 const auto tmp_download_sym_file_spec = 311 JoinPath(module_spec_dir, kTempSymFileName); 312 error = symfile_downloader(cached_module_sp, tmp_download_sym_file_spec); 313 llvm::FileRemover tmp_symfile_remover(tmp_download_sym_file_spec.GetPath()); 314 if (error.Fail()) 315 // Failed to download a symfile but fetching the module was successful. The 316 // module might contain the necessary symbols and the debugging is also 317 // possible without a symfile. 318 return Status(); 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 Status("Failed to put symbol file into cache: %s", 325 error.AsCString()); 326 327 tmp_symfile_remover.releaseFile(); 328 329 FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec()); 330 cached_module_sp->SetSymbolFileFileSpec(symfile_spec); 331 return Status(); 332 } 333