storage/browser/fileapi/obfuscated_file_util.h

   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 #ifndef STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_
   6 #define STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_
   7
   8 #include <map>
   9 #include <set>
  10 #include <string>
  11 #include <vector>
  12
  13 #include "base/callback_forward.h"
  14 #include "base/files/file.h"
  15 #include "base/files/file_path.h"
  16 #include "base/files/file_util_proxy.h"
  17 #include "base/gtest_prod_util.h"
  18 #include "base/memory/scoped_ptr.h"
  19 #include "storage/browser/blob/shareable_file_reference.h"
  20 #include "storage/browser/fileapi/file_system_file_util.h"
  21 #include "storage/browser/fileapi/file_system_url.h"
  22 #include "storage/browser/fileapi/sandbox_directory_database.h"
  23 #include "storage/browser/fileapi/sandbox_file_system_backend_delegate.h"
  24 #include "storage/browser/storage_browser_export.h"
  25 #include "storage/common/fileapi/file_system_types.h"
  26
  27 namespace base {
  28 class SequencedTaskRunner;
  29 class TimeTicks;
  30 }
  31
  32 namespace content {
  33 class ObfuscatedFileUtilTest;
  34 class QuotaBackendImplTest;
  35 }
  36
  37 namespace storage {
  38 class SpecialStoragePolicy;
  39 }
  40
  41 class GURL;
  42
  43 namespace storage {
  44
  45 class FileSystemOperationContext;
  46 class SandboxOriginDatabaseInterface;
  47 class TimedTaskHelper;
  48
  49 // This file util stores directory information in LevelDB to obfuscate
  50 // and to neutralize virtual file paths given by arbitrary apps.
  51 // Files are stored with two-level isolation: per-origin and per-type.
  52 // The isolation is done by storing data in separate directory partitions.
  53 // For example, a file in Temporary file system for origin 'www.example.com'
  54 // is stored in a different partition for a file in Persistent file system
  55 // for the same origin, or for Temporary file system for another origin.
  56 //
  57 // * Per-origin directory name information is stored in a separate LevelDB,
  58 //   which is maintained by SandboxOriginDatabase.
  59 // * Per-type directory name information is given by
  60 //   GetTypeStringForURLCallback that is given in CTOR.
  61 //   We use a small static mapping (e.g. 't' for Temporary type) for
  62 //   regular sandbox filesystems.
  63 //
  64 // The overall implementation philosophy of this class is that partial failures
  65 // should leave us with an intact database; we'd prefer to leak the occasional
  66 // backing file than have a database entry whose backing file is missing.  When
  67 // doing FSCK operations, if you find a loose backing file with no reference,
  68 // you may safely delete it.
  69 //
  70 // This class must be deleted on the FILE thread, because that's where
  71 // DropDatabases needs to be called.
  72 class STORAGE_EXPORT_PRIVATE ObfuscatedFileUtil
  73     : public FileSystemFileUtil {
  74  public:
  75   // Origin enumerator interface.
  76   // An instance of this interface is assumed to be called on the file thread.
  77   class AbstractOriginEnumerator {
  78    public:
  79     virtual ~AbstractOriginEnumerator() {}
  80
  81     // Returns the next origin.  Returns empty if there are no more origins.
  82     virtual GURL Next() = 0;
  83
  84     // Returns the current origin's information.
  85     // |type_string| must be ascii string.
  86     virtual bool HasTypeDirectory(const std::string& type_string) const = 0;
  87   };
  88
  89   typedef base::Callback<std::string(const FileSystemURL&)>
  90       GetTypeStringForURLCallback;
  91
  92   // |get_type_string_for_url| is user-defined callback that should return
  93   // a type string for the given FileSystemURL.  The type string is used
  94   // to provide per-type isolation in the sandboxed filesystem directory.
  95   // Note that this method is called on file_task_runner.
  96   //
  97   // |known_type_strings| are known type string names that this file system
  98   // should care about.
  99   // This info is used to determine whether we could delete the entire
 100   // origin directory or not in DeleteDirectoryForOriginAndType. If no directory
 101   // for any known type exists the origin directory may get deleted when
 102   // one origin/type pair is deleted.
 103   //
 104   ObfuscatedFileUtil(storage::SpecialStoragePolicy* special_storage_policy,
 105                      const base::FilePath& file_system_directory,
 106                      leveldb::Env* env_override,
 107                      base::SequencedTaskRunner* file_task_runner,
 108                      const GetTypeStringForURLCallback& get_type_string_for_url,
 109                      const std::set<std::string>& known_type_strings,
 110                      SandboxFileSystemBackendDelegate* sandbox_delegate);
 111   ~ObfuscatedFileUtil() override;
 112
 113   // FileSystemFileUtil overrides.
 114   base::File CreateOrOpen(FileSystemOperationContext* context,
 115                           const FileSystemURL& url,
 116                           int file_flags) override;
 117   base::File::Error EnsureFileExists(FileSystemOperationContext* context,
 118                                      const FileSystemURL& url,
 119                                      bool* created) override;
 120   base::File::Error CreateDirectory(FileSystemOperationContext* context,
 121                                     const FileSystemURL& url,
 122                                     bool exclusive,
 123                                     bool recursive) override;
 124   base::File::Error GetFileInfo(FileSystemOperationContext* context,
 125                                 const FileSystemURL& url,
 126                                 base::File::Info* file_info,
 127                                 base::FilePath* platform_file) override;
 128   scoped_ptr<AbstractFileEnumerator> CreateFileEnumerator(
 129       FileSystemOperationContext* context,
 130       const FileSystemURL& root_url) override;
 131   base::File::Error GetLocalFilePath(FileSystemOperationContext* context,
 132                                      const FileSystemURL& file_system_url,
 133                                      base::FilePath* local_path) override;
 134   base::File::Error Touch(FileSystemOperationContext* context,
 135                           const FileSystemURL& url,
 136                           const base::Time& last_access_time,
 137                           const base::Time& last_modified_time) override;
 138   base::File::Error Truncate(FileSystemOperationContext* context,
 139                              const FileSystemURL& url,
 140                              int64 length) override;
 141   base::File::Error CopyOrMoveFile(FileSystemOperationContext* context,
 142                                    const FileSystemURL& src_url,
 143                                    const FileSystemURL& dest_url,
 144                                    CopyOrMoveOption option,
 145                                    bool copy) override;
 146   base::File::Error CopyInForeignFile(FileSystemOperationContext* context,
 147                                       const base::FilePath& src_file_path,
 148                                       const FileSystemURL& dest_url) override;
 149   base::File::Error DeleteFile(FileSystemOperationContext* context,
 150                                const FileSystemURL& url) override;
 151   base::File::Error DeleteDirectory(FileSystemOperationContext* context,
 152                                     const FileSystemURL& url) override;
 153   storage::ScopedFile CreateSnapshotFile(
 154       FileSystemOperationContext* context,
 155       const FileSystemURL& url,
 156       base::File::Error* error,
 157       base::File::Info* file_info,
 158       base::FilePath* platform_path) override;
 159
 160   // Same as the other CreateFileEnumerator, but with recursive support.
 161   scoped_ptr<AbstractFileEnumerator> CreateFileEnumerator(
 162       FileSystemOperationContext* context,
 163       const FileSystemURL& root_url,
 164       bool recursive);
 165
 166   // Returns true if the directory |url| is empty.
 167   bool IsDirectoryEmpty(
 168       FileSystemOperationContext* context,
 169       const FileSystemURL& url);
 170
 171   // Gets the topmost directory specific to this origin and type.  This will
 172   // contain both the directory database's files and all the backing file
 173   // subdirectories.
 174   // Returns the topmost origin directory if |type_string| is empty.
 175   // Returns an empty path if the directory is undefined.
 176   // If the directory is defined, it will be returned, even if
 177   // there is a file system error (e.g. the directory doesn't exist on disk and
 178   // |create| is false). Callers should always check |error_code| to make sure
 179   // the returned path is usable.
 180   base::FilePath GetDirectoryForOriginAndType(
 181       const GURL& origin,
 182       const std::string& type_string,
 183       bool create,
 184       base::File::Error* error_code);
 185
 186   // Deletes the topmost directory specific to this origin and type.  This will
 187   // delete its directory database.
 188   // Deletes the topmost origin directory if |type_string| is empty.
 189   bool DeleteDirectoryForOriginAndType(
 190       const GURL& origin,
 191       const std::string& type_string);
 192
 193   // Frees resources used by an origin's filesystem.
 194   void CloseFileSystemForOriginAndType(const GURL& origin,
 195                                        const std::string& type_string);
 196
 197   // This method and all methods of its returned class must be called only on
 198   // the FILE thread.  The caller is responsible for deleting the returned
 199   // object.
 200   AbstractOriginEnumerator* CreateOriginEnumerator();
 201
 202   // Deletes a directory database from the database list in the ObfuscatedFSFU
 203   // and destroys the database on the disk.
 204   void DestroyDirectoryDatabase(const GURL& origin,
 205                                 const std::string& type_string);
 206
 207   // Computes a cost for storing a given file in the obfuscated FSFU.
 208   // As the cost of a file is independent of the cost of its parent directories,
 209   // this ignores all but the BaseName of the supplied path.  In order to
 210   // compute the cost of adding a multi-segment directory recursively, call this
 211   // on each path segment and add the results.
 212   static int64 ComputeFilePathCost(const base::FilePath& path);
 213
 214   // Tries to prepopulate directory database for the given type strings.
 215   // This tries from the first one in the given type_strings and stops
 216   // once it succeeds to do so for one database (i.e. it prepopulates
 217   // at most one database).
 218   void MaybePrepopulateDatabase(
 219       const std::vector<std::string>& type_strings_to_prepopulate);
 220
 221  private:
 222   typedef SandboxDirectoryDatabase::FileId FileId;
 223   typedef SandboxDirectoryDatabase::FileInfo FileInfo;
 224
 225   friend class ObfuscatedFileEnumerator;
 226   friend class content::ObfuscatedFileUtilTest;
 227   friend class content::QuotaBackendImplTest;
 228
 229   // Helper method to create an obfuscated file util for regular
 230   // (temporary, persistent) file systems. Used only for testing.
 231   // Note: this is implemented in sandbox_file_system_backend_delegate.cc.
 232   static ObfuscatedFileUtil* CreateForTesting(
 233       storage::SpecialStoragePolicy* special_storage_policy,
 234       const base::FilePath& file_system_directory,
 235       leveldb::Env* env_override,
 236       base::SequencedTaskRunner* file_task_runner);
 237
 238   base::FilePath GetDirectoryForURL(
 239       const FileSystemURL& url,
 240       bool create,
 241       base::File::Error* error_code);
 242
 243   // This just calls get_type_string_for_url_ callback that is given in ctor.
 244   std::string CallGetTypeStringForURL(const FileSystemURL& url);
 245
 246   base::File::Error GetFileInfoInternal(
 247       SandboxDirectoryDatabase* db,
 248       FileSystemOperationContext* context,
 249       const FileSystemURL& url,
 250       FileId file_id,
 251       FileInfo* local_info,
 252       base::File::Info* file_info,
 253       base::FilePath* platform_file_path);
 254
 255   // Creates a new file, both the underlying backing file and the entry in the
 256   // database.  |dest_file_info| is an in-out parameter.  Supply the name and
 257   // parent_id; data_path is ignored.  On success, data_path will
 258   // always be set to the relative path [from the root of the type-specific
 259   // filesystem directory] of a NEW backing file.  Returns the new file.
 260   base::File CreateAndOpenFile(
 261       FileSystemOperationContext* context,
 262       const FileSystemURL& dest_url,
 263       FileInfo* dest_file_info,
 264       int file_flags);
 265
 266   // The same as CreateAndOpenFile except that a file is not returned and if a
 267   // path is provided in |source_path|, it will be used as a source from which
 268   // to COPY data.
 269   base::File::Error CreateFile(
 270       FileSystemOperationContext* context,
 271       const base::FilePath& source_file_path,
 272       const FileSystemURL& dest_url,
 273       FileInfo* dest_file_info);
 274
 275   // Updates |db| and |dest_file_info| at the end of creating a new file.
 276   base::File::Error CommitCreateFile(
 277     const base::FilePath& root,
 278     const base::FilePath& local_path,
 279     SandboxDirectoryDatabase* db,
 280     FileInfo* dest_file_info);
 281
 282   // This converts from a relative path [as is stored in the FileInfo.data_path
 283   // field] to an absolute platform path that can be given to the native
 284   // filesystem.
 285   base::FilePath DataPathToLocalPath(
 286       const FileSystemURL& url,
 287       const base::FilePath& data_file_path);
 288
 289   std::string GetDirectoryDatabaseKey(const GURL& origin,
 290                                       const std::string& type_string);
 291
 292   // This returns NULL if |create| flag is false and a filesystem does not
 293   // exist for the given |url|.
 294   // For read operations |create| should be false.
 295   SandboxDirectoryDatabase* GetDirectoryDatabase(const FileSystemURL& url,
 296                                                  bool create);
 297
 298   // Gets the topmost directory specific to this origin.  This will
 299   // contain both the filesystem type subdirectories.
 300   base::FilePath GetDirectoryForOrigin(const GURL& origin,
 301                                        bool create,
 302                                        base::File::Error* error_code);
 303
 304   void InvalidateUsageCache(FileSystemOperationContext* context,
 305                             const GURL& origin,
 306                             FileSystemType type);
 307
 308   void MarkUsed();
 309   void DropDatabases();
 310
 311   // Initializes the origin database. |origin_hint| may be used as a hint
 312   // for initializing database if it's not empty.
 313   bool InitOriginDatabase(const GURL& origin_hint, bool create);
 314
 315   base::File::Error GenerateNewLocalPath(
 316       SandboxDirectoryDatabase* db,
 317       FileSystemOperationContext* context,
 318       const FileSystemURL& url,
 319       base::FilePath* root,
 320       base::FilePath* local_path);
 321
 322   base::File CreateOrOpenInternal(
 323       FileSystemOperationContext* context,
 324       const FileSystemURL& url,
 325       int file_flags);
 326
 327   bool HasIsolatedStorage(const GURL& origin);
 328
 329   typedef std::map<std::string, SandboxDirectoryDatabase*> DirectoryMap;
 330   DirectoryMap directories_;
 331   scoped_ptr<SandboxOriginDatabaseInterface> origin_database_;
 332   scoped_refptr<storage::SpecialStoragePolicy> special_storage_policy_;
 333   base::FilePath file_system_directory_;
 334   leveldb::Env* env_override_;
 335
 336   // Used to delete database after a certain period of inactivity.
 337   int64 db_flush_delay_seconds_;
 338
 339   scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
 340   scoped_ptr<TimedTaskHelper> timer_;
 341
 342   GetTypeStringForURLCallback get_type_string_for_url_;
 343   std::set<std::string> known_type_strings_;
 344
 345   // Not owned.
 346   SandboxFileSystemBackendDelegate* sandbox_delegate_;
 347
 348   DISALLOW_COPY_AND_ASSIGN(ObfuscatedFileUtil);
 349 };
 350
 351 }  // namespace storage
 352
 353 #endif  // STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_