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/fileapi/file_system_file_util.h"
20#include "storage/browser/fileapi/file_system_url.h"
21#include "storage/browser/fileapi/sandbox_directory_database.h"
22#include "storage/browser/fileapi/sandbox_file_system_backend_delegate.h"
23#include "storage/browser/storage_browser_export.h"
24#include "storage/common/blob/shareable_file_reference.h"
25#include "storage/common/fileapi/file_system_types.h"
26
27namespace base {
28class SequencedTaskRunner;
29class TimeTicks;
30}
31
32namespace content {
33class ObfuscatedFileUtilTest;
34class QuotaBackendImplTest;
35}
36
37namespace storage {
38class SpecialStoragePolicy;
39}
40
41class GURL;
42
43namespace storage {
44
45class FileSystemOperationContext;
46class SandboxOriginDatabaseInterface;
47class 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.
72class 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  virtual ~ObfuscatedFileUtil();
112
113  // FileSystemFileUtil overrides.
114  virtual base::File CreateOrOpen(
115      FileSystemOperationContext* context,
116      const FileSystemURL& url,
117      int file_flags) OVERRIDE;
118  virtual base::File::Error EnsureFileExists(
119      FileSystemOperationContext* context,
120      const FileSystemURL& url, bool* created) OVERRIDE;
121  virtual base::File::Error CreateDirectory(
122      FileSystemOperationContext* context,
123      const FileSystemURL& url,
124      bool exclusive,
125      bool recursive) OVERRIDE;
126  virtual base::File::Error GetFileInfo(
127      FileSystemOperationContext* context,
128      const FileSystemURL& url,
129      base::File::Info* file_info,
130      base::FilePath* platform_file) OVERRIDE;
131  virtual scoped_ptr<AbstractFileEnumerator> CreateFileEnumerator(
132      FileSystemOperationContext* context,
133      const FileSystemURL& root_url) OVERRIDE;
134  virtual base::File::Error GetLocalFilePath(
135      FileSystemOperationContext* context,
136      const FileSystemURL& file_system_url,
137      base::FilePath* local_path) OVERRIDE;
138  virtual base::File::Error Touch(
139      FileSystemOperationContext* context,
140      const FileSystemURL& url,
141      const base::Time& last_access_time,
142      const base::Time& last_modified_time) OVERRIDE;
143  virtual base::File::Error Truncate(
144      FileSystemOperationContext* context,
145      const FileSystemURL& url,
146      int64 length) OVERRIDE;
147  virtual base::File::Error CopyOrMoveFile(
148      FileSystemOperationContext* context,
149      const FileSystemURL& src_url,
150      const FileSystemURL& dest_url,
151      CopyOrMoveOption option,
152      bool copy) OVERRIDE;
153  virtual base::File::Error CopyInForeignFile(
154        FileSystemOperationContext* context,
155        const base::FilePath& src_file_path,
156        const FileSystemURL& dest_url) OVERRIDE;
157  virtual base::File::Error DeleteFile(
158      FileSystemOperationContext* context,
159      const FileSystemURL& url) OVERRIDE;
160  virtual base::File::Error DeleteDirectory(
161      FileSystemOperationContext* context,
162      const FileSystemURL& url) OVERRIDE;
163  virtual storage::ScopedFile CreateSnapshotFile(
164      FileSystemOperationContext* context,
165      const FileSystemURL& url,
166      base::File::Error* error,
167      base::File::Info* file_info,
168      base::FilePath* platform_path) OVERRIDE;
169
170  // Same as the other CreateFileEnumerator, but with recursive support.
171  scoped_ptr<AbstractFileEnumerator> CreateFileEnumerator(
172      FileSystemOperationContext* context,
173      const FileSystemURL& root_url,
174      bool recursive);
175
176  // Returns true if the directory |url| is empty.
177  bool IsDirectoryEmpty(
178      FileSystemOperationContext* context,
179      const FileSystemURL& url);
180
181  // Gets the topmost directory specific to this origin and type.  This will
182  // contain both the directory database's files and all the backing file
183  // subdirectories.
184  // Returns the topmost origin directory if |type_string| is empty.
185  // Returns an empty path if the directory is undefined.
186  // If the directory is defined, it will be returned, even if
187  // there is a file system error (e.g. the directory doesn't exist on disk and
188  // |create| is false). Callers should always check |error_code| to make sure
189  // the returned path is usable.
190  base::FilePath GetDirectoryForOriginAndType(
191      const GURL& origin,
192      const std::string& type_string,
193      bool create,
194      base::File::Error* error_code);
195
196  // Deletes the topmost directory specific to this origin and type.  This will
197  // delete its directory database.
198  // Deletes the topmost origin directory if |type_string| is empty.
199  bool DeleteDirectoryForOriginAndType(
200      const GURL& origin,
201      const std::string& type_string);
202
203  // This method and all methods of its returned class must be called only on
204  // the FILE thread.  The caller is responsible for deleting the returned
205  // object.
206  AbstractOriginEnumerator* CreateOriginEnumerator();
207
208  // Deletes a directory database from the database list in the ObfuscatedFSFU
209  // and destroys the database on the disk.
210  bool DestroyDirectoryDatabase(const GURL& origin,
211                                const std::string& type_string);
212
213  // Computes a cost for storing a given file in the obfuscated FSFU.
214  // As the cost of a file is independent of the cost of its parent directories,
215  // this ignores all but the BaseName of the supplied path.  In order to
216  // compute the cost of adding a multi-segment directory recursively, call this
217  // on each path segment and add the results.
218  static int64 ComputeFilePathCost(const base::FilePath& path);
219
220  // Tries to prepopulate directory database for the given type strings.
221  // This tries from the first one in the given type_strings and stops
222  // once it succeeds to do so for one database (i.e. it prepopulates
223  // at most one database).
224  void MaybePrepopulateDatabase(
225      const std::vector<std::string>& type_strings_to_prepopulate);
226
227 private:
228  typedef SandboxDirectoryDatabase::FileId FileId;
229  typedef SandboxDirectoryDatabase::FileInfo FileInfo;
230
231  friend class ObfuscatedFileEnumerator;
232  friend class content::ObfuscatedFileUtilTest;
233  friend class content::QuotaBackendImplTest;
234
235  // Helper method to create an obfuscated file util for regular
236  // (temporary, persistent) file systems. Used only for testing.
237  // Note: this is implemented in sandbox_file_system_backend_delegate.cc.
238  static ObfuscatedFileUtil* CreateForTesting(
239      storage::SpecialStoragePolicy* special_storage_policy,
240      const base::FilePath& file_system_directory,
241      leveldb::Env* env_override,
242      base::SequencedTaskRunner* file_task_runner);
243
244  base::FilePath GetDirectoryForURL(
245      const FileSystemURL& url,
246      bool create,
247      base::File::Error* error_code);
248
249  // This just calls get_type_string_for_url_ callback that is given in ctor.
250  std::string CallGetTypeStringForURL(const FileSystemURL& url);
251
252  base::File::Error GetFileInfoInternal(
253      SandboxDirectoryDatabase* db,
254      FileSystemOperationContext* context,
255      const FileSystemURL& url,
256      FileId file_id,
257      FileInfo* local_info,
258      base::File::Info* file_info,
259      base::FilePath* platform_file_path);
260
261  // Creates a new file, both the underlying backing file and the entry in the
262  // database.  |dest_file_info| is an in-out parameter.  Supply the name and
263  // parent_id; data_path is ignored.  On success, data_path will
264  // always be set to the relative path [from the root of the type-specific
265  // filesystem directory] of a NEW backing file.  Returns the new file.
266  base::File CreateAndOpenFile(
267      FileSystemOperationContext* context,
268      const FileSystemURL& dest_url,
269      FileInfo* dest_file_info,
270      int file_flags);
271
272  // The same as CreateAndOpenFile except that a file is not returned and if a
273  // path is provided in |source_path|, it will be used as a source from which
274  // to COPY data.
275  base::File::Error CreateFile(
276      FileSystemOperationContext* context,
277      const base::FilePath& source_file_path,
278      const FileSystemURL& dest_url,
279      FileInfo* dest_file_info);
280
281  // Updates |db| and |dest_file_info| at the end of creating a new file.
282  base::File::Error CommitCreateFile(
283    const base::FilePath& root,
284    const base::FilePath& local_path,
285    SandboxDirectoryDatabase* db,
286    FileInfo* dest_file_info);
287
288  // This converts from a relative path [as is stored in the FileInfo.data_path
289  // field] to an absolute platform path that can be given to the native
290  // filesystem.
291  base::FilePath DataPathToLocalPath(
292      const FileSystemURL& url,
293      const base::FilePath& data_file_path);
294
295  std::string GetDirectoryDatabaseKey(const GURL& origin,
296                                      const std::string& type_string);
297
298  // This returns NULL if |create| flag is false and a filesystem does not
299  // exist for the given |url|.
300  // For read operations |create| should be false.
301  SandboxDirectoryDatabase* GetDirectoryDatabase(const FileSystemURL& url,
302                                                 bool create);
303
304  // Gets the topmost directory specific to this origin.  This will
305  // contain both the filesystem type subdirectories.
306  base::FilePath GetDirectoryForOrigin(const GURL& origin,
307                                       bool create,
308                                       base::File::Error* error_code);
309
310  void InvalidateUsageCache(FileSystemOperationContext* context,
311                            const GURL& origin,
312                            FileSystemType type);
313
314  void MarkUsed();
315  void DropDatabases();
316
317  // Initializes the origin database. |origin_hint| may be used as a hint
318  // for initializing database if it's not empty.
319  bool InitOriginDatabase(const GURL& origin_hint, bool create);
320
321  base::File::Error GenerateNewLocalPath(
322      SandboxDirectoryDatabase* db,
323      FileSystemOperationContext* context,
324      const FileSystemURL& url,
325      base::FilePath* root,
326      base::FilePath* local_path);
327
328  base::File CreateOrOpenInternal(
329      FileSystemOperationContext* context,
330      const FileSystemURL& url,
331      int file_flags);
332
333  bool HasIsolatedStorage(const GURL& origin);
334
335  typedef std::map<std::string, SandboxDirectoryDatabase*> DirectoryMap;
336  DirectoryMap directories_;
337  scoped_ptr<SandboxOriginDatabaseInterface> origin_database_;
338  scoped_refptr<storage::SpecialStoragePolicy> special_storage_policy_;
339  base::FilePath file_system_directory_;
340  leveldb::Env* env_override_;
341
342  // Used to delete database after a certain period of inactivity.
343  int64 db_flush_delay_seconds_;
344
345  scoped_refptr<base::SequencedTaskRunner> file_task_runner_;
346  scoped_ptr<TimedTaskHelper> timer_;
347
348  GetTypeStringForURLCallback get_type_string_for_url_;
349  std::set<std::string> known_type_strings_;
350
351  // Not owned.
352  SandboxFileSystemBackendDelegate* sandbox_delegate_;
353
354  DISALLOW_COPY_AND_ASSIGN(ObfuscatedFileUtil);
355};
356
357}  // namespace storage
358
359#endif  // STORAGE_BROWSER_FILEAPI_OBFUSCATED_FILE_UTIL_H_
360