ModuleCache.cpp revision 360784 
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
24using namespace lldb;
25using namespace lldb_private;
26
27namespace {
28
29const char *kModulesSubdir = ".cache";
30const char *kLockDirName = ".lock";
31const char *kTempFileName = ".temp";
32const char *kTempSymFileName = ".symtemp";
33const char *kSymFileExtension = ".sym";
34const char *kFSIllegalChars = "\\/:*?\"<>|";
35
36std::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
49class ModuleLock {
50private:
51  FileUP m_file_up;
52  std::unique_ptr<lldb_private::LockFile> m_lock;
53  FileSpec m_file_spec;
54
55public:
56  ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid, Status &error);
57  void Delete();
58};
59
60static FileSpec JoinPath(const FileSpec &path1, const char *path2) {
61  FileSpec result_spec(path1);
62  result_spec.AppendPathComponent(path2);
63  return result_spec;
64}
65
66static 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
72FileSpec 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
77FileSpec GetSymbolFileSpec(const FileSpec &module_file_spec) {
78  return FileSpec(module_file_spec.GetPath() + kSymFileExtension);
79}
80
81void 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    LLDB_LOGF(log, "Failed to lock module %s: %s",
98              module_uuid.GetAsString().c_str(), error.AsCString());
99  }
100
101  namespace fs = llvm::sys::fs;
102  fs::file_status st;
103  if (status(sysroot_module_path_spec.GetPath(), st))
104    return;
105
106  if (st.getLinkCount() > 2) // module is referred by other hosts.
107    return;
108
109  const auto module_spec_dir = GetModuleDirectory(root_dir_spec, module_uuid);
110  llvm::sys::fs::remove_directories(module_spec_dir.GetPath());
111  lock.Delete();
112}
113
114void DecrementRefExistingModule(const FileSpec &root_dir_spec,
115                                const FileSpec &sysroot_module_path_spec) {
116  // Remove $platform/.cache/$uuid folder if nobody else references it.
117  DeleteExistingModule(root_dir_spec, sysroot_module_path_spec);
118
119  // Remove sysroot link.
120  llvm::sys::fs::remove(sysroot_module_path_spec.GetPath());
121
122  FileSpec symfile_spec = GetSymbolFileSpec(sysroot_module_path_spec);
123  llvm::sys::fs::remove(symfile_spec.GetPath());
124}
125
126Status CreateHostSysRootModuleLink(const FileSpec &root_dir_spec,
127                                   const char *hostname,
128                                   const FileSpec &platform_module_spec,
129                                   const FileSpec &local_module_spec,
130                                   bool delete_existing) {
131  const auto sysroot_module_path_spec =
132      JoinPath(JoinPath(root_dir_spec, hostname),
133               platform_module_spec.GetPath().c_str());
134  if (FileSystem::Instance().Exists(sysroot_module_path_spec)) {
135    if (!delete_existing)
136      return Status();
137
138    DecrementRefExistingModule(root_dir_spec, sysroot_module_path_spec);
139  }
140
141  const auto error = MakeDirectory(
142      FileSpec(sysroot_module_path_spec.GetDirectory().AsCString()));
143  if (error.Fail())
144    return error;
145
146  return llvm::sys::fs::create_hard_link(local_module_spec.GetPath(),
147                                         sysroot_module_path_spec.GetPath());
148}
149
150} // namespace
151
152ModuleLock::ModuleLock(const FileSpec &root_dir_spec, const UUID &uuid,
153                       Status &error) {
154  const auto lock_dir_spec = JoinPath(root_dir_spec, kLockDirName);
155  error = MakeDirectory(lock_dir_spec);
156  if (error.Fail())
157    return;
158
159  m_file_spec = JoinPath(lock_dir_spec, uuid.GetAsString().c_str());
160
161  auto file = FileSystem::Instance().Open(
162      m_file_spec, File::eOpenOptionWrite | File::eOpenOptionCanCreate |
163                       File::eOpenOptionCloseOnExec);
164  if (file)
165    m_file_up = std::move(file.get());
166  else {
167    m_file_up.reset();
168    error = Status(file.takeError());
169    return;
170  }
171
172  m_lock.reset(new lldb_private::LockFile(m_file_up->GetDescriptor()));
173  error = m_lock->WriteLock(0, 1);
174  if (error.Fail())
175    error.SetErrorStringWithFormat("Failed to lock file: %s",
176                                   error.AsCString());
177}
178
179void ModuleLock::Delete() {
180  if (!m_file_up)
181    return;
182
183  m_file_up->Close();
184  m_file_up.reset();
185  llvm::sys::fs::remove(m_file_spec.GetPath());
186}
187
188/////////////////////////////////////////////////////////////////////////
189
190Status ModuleCache::Put(const FileSpec &root_dir_spec, const char *hostname,
191                        const ModuleSpec &module_spec, const FileSpec &tmp_file,
192                        const FileSpec &target_file) {
193  const auto module_spec_dir =
194      GetModuleDirectory(root_dir_spec, module_spec.GetUUID());
195  const auto module_file_path =
196      JoinPath(module_spec_dir, target_file.GetFilename().AsCString());
197
198  const auto tmp_file_path = tmp_file.GetPath();
199  const auto err_code =
200      llvm::sys::fs::rename(tmp_file_path, module_file_path.GetPath());
201  if (err_code)
202    return Status("Failed to rename file %s to %s: %s", tmp_file_path.c_str(),
203                  module_file_path.GetPath().c_str(),
204                  err_code.message().c_str());
205
206  const auto error = CreateHostSysRootModuleLink(
207      root_dir_spec, hostname, target_file, module_file_path, true);
208  if (error.Fail())
209    return Status("Failed to create link to %s: %s",
210                  module_file_path.GetPath().c_str(), error.AsCString());
211  return Status();
212}
213
214Status ModuleCache::Get(const FileSpec &root_dir_spec, const char *hostname,
215                        const ModuleSpec &module_spec,
216                        ModuleSP &cached_module_sp, bool *did_create_ptr) {
217  const auto find_it =
218      m_loaded_modules.find(module_spec.GetUUID().GetAsString());
219  if (find_it != m_loaded_modules.end()) {
220    cached_module_sp = (*find_it).second.lock();
221    if (cached_module_sp)
222      return Status();
223    m_loaded_modules.erase(find_it);
224  }
225
226  const auto module_spec_dir =
227      GetModuleDirectory(root_dir_spec, module_spec.GetUUID());
228  const auto module_file_path = JoinPath(
229      module_spec_dir, module_spec.GetFileSpec().GetFilename().AsCString());
230
231  if (!FileSystem::Instance().Exists(module_file_path))
232    return Status("Module %s not found", module_file_path.GetPath().c_str());
233  if (FileSystem::Instance().GetByteSize(module_file_path) !=
234      module_spec.GetObjectSize())
235    return Status("Module %s has invalid file size",
236                  module_file_path.GetPath().c_str());
237
238  // We may have already cached module but downloaded from an another host - in
239  // this case let's create a link to it.
240  auto error = CreateHostSysRootModuleLink(root_dir_spec, hostname,
241                                           module_spec.GetFileSpec(),
242                                           module_file_path, false);
243  if (error.Fail())
244    return Status("Failed to create link to %s: %s",
245                  module_file_path.GetPath().c_str(), error.AsCString());
246
247  auto cached_module_spec(module_spec);
248  cached_module_spec.GetUUID().Clear(); // Clear UUID since it may contain md5
249                                        // content hash instead of real UUID.
250  cached_module_spec.GetFileSpec() = module_file_path;
251  cached_module_spec.GetPlatformFileSpec() = module_spec.GetFileSpec();
252
253  error = ModuleList::GetSharedModule(cached_module_spec, cached_module_sp,
254                                      nullptr, nullptr, did_create_ptr, false);
255  if (error.Fail())
256    return error;
257
258  FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec());
259  if (FileSystem::Instance().Exists(symfile_spec))
260    cached_module_sp->SetSymbolFileFileSpec(symfile_spec);
261
262  m_loaded_modules.insert(
263      std::make_pair(module_spec.GetUUID().GetAsString(), cached_module_sp));
264
265  return Status();
266}
267
268Status ModuleCache::GetAndPut(const FileSpec &root_dir_spec,
269                              const char *hostname,
270                              const ModuleSpec &module_spec,
271                              const ModuleDownloader &module_downloader,
272                              const SymfileDownloader &symfile_downloader,
273                              lldb::ModuleSP &cached_module_sp,
274                              bool *did_create_ptr) {
275  const auto module_spec_dir =
276      GetModuleDirectory(root_dir_spec, module_spec.GetUUID());
277  auto error = MakeDirectory(module_spec_dir);
278  if (error.Fail())
279    return error;
280
281  ModuleLock lock(root_dir_spec, module_spec.GetUUID(), error);
282  if (error.Fail())
283    return Status("Failed to lock module %s: %s",
284                  module_spec.GetUUID().GetAsString().c_str(),
285                  error.AsCString());
286
287  const auto escaped_hostname(GetEscapedHostname(hostname));
288  // Check local cache for a module.
289  error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec,
290              cached_module_sp, did_create_ptr);
291  if (error.Success())
292    return error;
293
294  const auto tmp_download_file_spec = JoinPath(module_spec_dir, kTempFileName);
295  error = module_downloader(module_spec, tmp_download_file_spec);
296  llvm::FileRemover tmp_file_remover(tmp_download_file_spec.GetPath());
297  if (error.Fail())
298    return Status("Failed to download module: %s", error.AsCString());
299
300  // Put downloaded file into local module cache.
301  error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec,
302              tmp_download_file_spec, module_spec.GetFileSpec());
303  if (error.Fail())
304    return Status("Failed to put module into cache: %s", error.AsCString());
305
306  tmp_file_remover.releaseFile();
307  error = Get(root_dir_spec, escaped_hostname.c_str(), module_spec,
308              cached_module_sp, did_create_ptr);
309  if (error.Fail())
310    return error;
311
312  // Fetching a symbol file for the module
313  const auto tmp_download_sym_file_spec =
314      JoinPath(module_spec_dir, kTempSymFileName);
315  error = symfile_downloader(cached_module_sp, tmp_download_sym_file_spec);
316  llvm::FileRemover tmp_symfile_remover(tmp_download_sym_file_spec.GetPath());
317  if (error.Fail())
318    // Failed to download a symfile but fetching the module was successful. The
319    // module might contain the necessary symbols and the debugging is also
320    // possible without a symfile.
321    return Status();
322
323  error = Put(root_dir_spec, escaped_hostname.c_str(), module_spec,
324              tmp_download_sym_file_spec,
325              GetSymbolFileSpec(module_spec.GetFileSpec()));
326  if (error.Fail())
327    return Status("Failed to put symbol file into cache: %s",
328                  error.AsCString());
329
330  tmp_symfile_remover.releaseFile();
331
332  FileSpec symfile_spec = GetSymbolFileSpec(cached_module_sp->GetFileSpec());
333  cached_module_sp->SetSymbolFileFileSpec(symfile_spec);
334  return Status();
335}
336