chrome/browser/extensions/external_pref_loader.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "chrome/browser/extensions/external_pref_loader.h"
   6
   7 #include "base/bind.h"
   8 #include "base/file_util.h"
   9 #include "base/files/file_enumerator.h"
  10 #include "base/files/file_path.h"
  11 #include "base/json/json_file_value_serializer.h"
  12 #include "base/json/json_string_value_serializer.h"
  13 #include "base/logging.h"
  14 #include "base/metrics/histogram.h"
  15 #include "base/path_service.h"
  16 #include "base/strings/string_util.h"
  17 #include "base/strings/utf_string_conversions.h"
  18 #include "chrome/common/chrome_paths.h"
  19 #include "content/public/browser/browser_thread.h"
  20
  21 using content::BrowserThread;
  22
  23 namespace {
  24
  25 base::FilePath::CharType kExternalExtensionJson[] =
  26     FILE_PATH_LITERAL("external_extensions.json");
  27
  28 std::set<base::FilePath> GetPrefsCandidateFilesFromFolder(
  29       const base::FilePath& external_extension_search_path) {
  30   CHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
  31
  32   std::set<base::FilePath> external_extension_paths;
  33
  34   if (!base::PathExists(external_extension_search_path)) {
  35     // Does not have to exist.
  36     return external_extension_paths;
  37   }
  38
  39   base::FileEnumerator json_files(
  40       external_extension_search_path,
  41       false,  // Recursive.
  42       base::FileEnumerator::FILES);
  43 #if defined(OS_WIN)
  44   base::FilePath::StringType extension = UTF8ToWide(std::string(".json"));
  45 #elif defined(OS_POSIX)
  46   base::FilePath::StringType extension(".json");
  47 #endif
  48   do {
  49     base::FilePath file = json_files.Next();
  50     if (file.BaseName().value() == kExternalExtensionJson)
  51       continue;  // Already taken care of elsewhere.
  52     if (file.empty())
  53       break;
  54     if (file.MatchesExtension(extension)) {
  55       external_extension_paths.insert(file.BaseName());
  56     } else {
  57       DVLOG(1) << "Not considering: " << file.LossyDisplayName()
  58                << " (does not have a .json extension)";
  59     }
  60   } while (true);
  61
  62   return external_extension_paths;
  63 }
  64
  65 // Extracts extension information from a json file serialized by |serializer|.
  66 // |path| is only used for informational purposes (outputted when an error
  67 // occurs). An empty dictionary is returned in case of failure (e.g. invalid
  68 // path or json content).
  69 // Caller takes ownership of the returned dictionary.
  70 DictionaryValue* ExtractExtensionPrefs(base::ValueSerializer* serializer,
  71                                        const base::FilePath& path) {
  72   std::string error_msg;
  73   Value* extensions = serializer->Deserialize(NULL, &error_msg);
  74   if (!extensions) {
  75     LOG(WARNING) << "Unable to deserialize json data: " << error_msg
  76                  << " in file " << path.value() << ".";
  77     return new DictionaryValue;
  78   }
  79
  80   DictionaryValue* ext_dictionary = NULL;
  81   if (extensions->GetAsDictionary(&ext_dictionary))
  82     return ext_dictionary;
  83
  84   LOG(WARNING) << "Expected a JSON dictionary in file "
  85                << path.value() << ".";
  86   return new DictionaryValue;
  87 }
  88
  89 }  // namespace
  90
  91 namespace extensions {
  92
  93 ExternalPrefLoader::ExternalPrefLoader(int base_path_id, Options options)
  94     : base_path_id_(base_path_id), options_(options) {
  95   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
  96 }
  97
  98 const base::FilePath ExternalPrefLoader::GetBaseCrxFilePath() {
  99   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 100
 101   // |base_path_| was set in LoadOnFileThread().
 102   return base_path_;
 103 }
 104
 105 void ExternalPrefLoader::StartLoading() {
 106   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 107   BrowserThread::PostTask(
 108       BrowserThread::FILE, FROM_HERE,
 109       base::Bind(&ExternalPrefLoader::LoadOnFileThread, this));
 110 }
 111
 112 void ExternalPrefLoader::LoadOnFileThread() {
 113   CHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 114
 115   scoped_ptr<DictionaryValue> prefs(new DictionaryValue);
 116
 117   // TODO(skerner): Some values of base_path_id_ will cause
 118   // PathService::Get() to return false, because the path does
 119   // not exist.  Find and fix the build/install scripts so that
 120   // this can become a CHECK().  Known examples include chrome
 121   // OS developer builds and linux install packages.
 122   // Tracked as crbug.com/70402 .
 123   if (PathService::Get(base_path_id_, &base_path_)) {
 124     ReadExternalExtensionPrefFile(prefs.get());
 125
 126     if (!prefs->empty())
 127       LOG(WARNING) << "You are using an old-style extension deployment method "
 128                       "(external_extensions.json), which will soon be "
 129                       "deprecated. (see http://code.google.com/chrome/"
 130                       "extensions/external_extensions.html )";
 131
 132     ReadStandaloneExtensionPrefFiles(prefs.get());
 133   }
 134
 135   prefs_.swap(prefs);
 136
 137   if (base_path_id_ == chrome::DIR_EXTERNAL_EXTENSIONS) {
 138     UMA_HISTOGRAM_COUNTS_100("Extensions.ExternalJsonCount",
 139                              prefs_->size());
 140   }
 141
 142   // If we have any records to process, then we must have
 143   // read at least one .json file.  If so, then we should have
 144   // set |base_path_|.
 145   if (!prefs_->empty())
 146     CHECK(!base_path_.empty());
 147
 148   BrowserThread::PostTask(
 149       BrowserThread::UI, FROM_HERE,
 150       base::Bind(&ExternalPrefLoader::LoadFinished, this));
 151 }
 152
 153 void ExternalPrefLoader::ReadExternalExtensionPrefFile(DictionaryValue* prefs) {
 154   CHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 155   CHECK(NULL != prefs);
 156
 157   base::FilePath json_file = base_path_.Append(kExternalExtensionJson);
 158
 159   if (!base::PathExists(json_file)) {
 160     // This is not an error.  The file does not exist by default.
 161     return;
 162   }
 163
 164   if (IsOptionSet(ENSURE_PATH_CONTROLLED_BY_ADMIN)) {
 165 #if defined(OS_MACOSX)
 166     if (!file_util::VerifyPathControlledByAdmin(json_file)) {
 167       LOG(ERROR) << "Can not read external extensions source.  The file "
 168                  << json_file.value() << " and every directory in its path, "
 169                  << "must be owned by root, have group \"admin\", and not be "
 170                  << "writable by all users. These restrictions prevent "
 171                  << "unprivleged users from making chrome install extensions "
 172                  << "on other users' accounts.";
 173       return;
 174     }
 175 #else
 176     // The only platform that uses this check is Mac OS.  If you add one,
 177     // you need to implement file_util::VerifyPathControlledByAdmin() for
 178     // that platform.
 179     NOTREACHED();
 180 #endif  // defined(OS_MACOSX)
 181   }
 182
 183   JSONFileValueSerializer serializer(json_file);
 184   scoped_ptr<DictionaryValue> ext_prefs(
 185       ExtractExtensionPrefs(&serializer, json_file));
 186   if (ext_prefs)
 187     prefs->MergeDictionary(ext_prefs.get());
 188 }
 189
 190 void ExternalPrefLoader::ReadStandaloneExtensionPrefFiles(
 191     DictionaryValue* prefs) {
 192   CHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE));
 193   CHECK(NULL != prefs);
 194
 195   // First list the potential .json candidates.
 196   std::set<base::FilePath>
 197       candidates = GetPrefsCandidateFilesFromFolder(base_path_);
 198   if (candidates.empty()) {
 199     DVLOG(1) << "Extension candidates list empty";
 200     return;
 201   }
 202
 203   // For each file read the json description & build the proper
 204   // associated prefs.
 205   for (std::set<base::FilePath>::const_iterator it = candidates.begin();
 206        it != candidates.end();
 207        ++it) {
 208     base::FilePath extension_candidate_path = base_path_.Append(*it);
 209
 210     std::string id =
 211 #if defined(OS_WIN)
 212         WideToASCII(
 213             extension_candidate_path.RemoveExtension().BaseName().value());
 214 #elif defined(OS_POSIX)
 215         extension_candidate_path.RemoveExtension().BaseName().value().c_str();
 216 #endif
 217
 218     DVLOG(1) << "Reading json file: "
 219              << extension_candidate_path.LossyDisplayName().c_str();
 220
 221     JSONFileValueSerializer serializer(extension_candidate_path);
 222     scoped_ptr<DictionaryValue> ext_prefs(
 223         ExtractExtensionPrefs(&serializer, extension_candidate_path));
 224     if (ext_prefs) {
 225       DVLOG(1) << "Adding extension with id: " << id;
 226       prefs->Set(id, ext_prefs.release());
 227     }
 228   }
 229 }
 230
 231 ExternalTestingLoader::ExternalTestingLoader(
 232     const std::string& json_data,
 233     const base::FilePath& fake_base_path)
 234     : fake_base_path_(fake_base_path) {
 235   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 236   JSONStringValueSerializer serializer(json_data);
 237   base::FilePath fake_json_path = fake_base_path.AppendASCII("fake.json");
 238   testing_prefs_.reset(ExtractExtensionPrefs(&serializer, fake_json_path));
 239 }
 240
 241 void ExternalTestingLoader::StartLoading() {
 242   CHECK(BrowserThread::CurrentlyOn(BrowserThread::UI));
 243   prefs_.reset(testing_prefs_->DeepCopy());
 244   LoadFinished();
 245 }
 246
 247 ExternalTestingLoader::~ExternalTestingLoader() {}
 248
 249 const base::FilePath ExternalTestingLoader::GetBaseCrxFilePath() {
 250   return fake_base_path_;
 251 }
 252
 253 }  // extensions