• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
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 // This file contains utility functions for dealing with the local
6 // filesystem.
7 
8 #ifndef BASE_FILE_UTIL_H_
9 #define BASE_FILE_UTIL_H_
10 
11 #include "build/build_config.h"
12 
13 #if defined(OS_WIN)
14 #include <windows.h>
15 #elif defined(OS_POSIX)
16 #include <sys/stat.h>
17 #include <unistd.h>
18 #endif
19 
20 #include <stdio.h>
21 
22 #include <set>
23 #include <string>
24 #include <vector>
25 
26 #include "base/base_export.h"
27 #include "base/basictypes.h"
28 #include "base/files/file_path.h"
29 #include "base/memory/scoped_ptr.h"
30 #include "base/platform_file.h"
31 #include "base/strings/string16.h"
32 
33 #if defined(OS_POSIX)
34 #include "base/file_descriptor_posix.h"
35 #include "base/logging.h"
36 #include "base/posix/eintr_wrapper.h"
37 #endif
38 
39 namespace base {
40 
41 class Time;
42 
43 //-----------------------------------------------------------------------------
44 // Functions that involve filesystem access or modification:
45 
46 // Returns an absolute version of a relative path. Returns an empty path on
47 // error. On POSIX, this function fails if the path does not exist. This
48 // function can result in I/O so it can be slow.
49 BASE_EXPORT FilePath MakeAbsoluteFilePath(const FilePath& input);
50 
51 // Returns the total number of bytes used by all the files under |root_path|.
52 // If the path does not exist the function returns 0.
53 //
54 // This function is implemented using the FileEnumerator class so it is not
55 // particularly speedy in any platform.
56 BASE_EXPORT int64 ComputeDirectorySize(const FilePath& root_path);
57 
58 // Deletes the given path, whether it's a file or a directory.
59 // If it's a directory, it's perfectly happy to delete all of the
60 // directory's contents.  Passing true to recursive deletes
61 // subdirectories and their contents as well.
62 // Returns true if successful, false otherwise. It is considered successful
63 // to attempt to delete a file that does not exist.
64 //
65 // In posix environment and if |path| is a symbolic link, this deletes only
66 // the symlink. (even if the symlink points to a non-existent file)
67 //
68 // WARNING: USING THIS WITH recursive==true IS EQUIVALENT
69 //          TO "rm -rf", SO USE WITH CAUTION.
70 BASE_EXPORT bool DeleteFile(const FilePath& path, bool recursive);
71 
72 #if defined(OS_WIN)
73 // Schedules to delete the given path, whether it's a file or a directory, until
74 // the operating system is restarted.
75 // Note:
76 // 1) The file/directory to be deleted should exist in a temp folder.
77 // 2) The directory to be deleted must be empty.
78 BASE_EXPORT bool DeleteFileAfterReboot(const FilePath& path);
79 #endif
80 
81 // Moves the given path, whether it's a file or a directory.
82 // If a simple rename is not possible, such as in the case where the paths are
83 // on different volumes, this will attempt to copy and delete. Returns
84 // true for success.
85 // This function fails if either path contains traversal components ('..').
86 BASE_EXPORT bool Move(const FilePath& from_path, const FilePath& to_path);
87 
88 // Renames file |from_path| to |to_path|. Both paths must be on the same
89 // volume, or the function will fail. Destination file will be created
90 // if it doesn't exist. Prefer this function over Move when dealing with
91 // temporary files. On Windows it preserves attributes of the target file.
92 // Returns true on success, leaving *error unchanged.
93 // Returns false on failure and sets *error appropriately, if it is non-NULL.
94 BASE_EXPORT bool ReplaceFile(const FilePath& from_path,
95                              const FilePath& to_path,
96                              PlatformFileError* error);
97 
98 // Copies a single file. Use CopyDirectory to copy directories.
99 // This function fails if either path contains traversal components ('..').
100 BASE_EXPORT bool CopyFile(const FilePath& from_path, const FilePath& to_path);
101 
102 // Copies the given path, and optionally all subdirectories and their contents
103 // as well.
104 //
105 // If there are files existing under to_path, always overwrite. Returns true
106 // if successful, false otherwise. Wildcards on the names are not supported.
107 //
108 // If you only need to copy a file use CopyFile, it's faster.
109 BASE_EXPORT bool CopyDirectory(const FilePath& from_path,
110                                const FilePath& to_path,
111                                bool recursive);
112 
113 // Returns true if the given path exists on the local filesystem,
114 // false otherwise.
115 BASE_EXPORT bool PathExists(const FilePath& path);
116 
117 // Returns true if the given path is writable by the user, false otherwise.
118 BASE_EXPORT bool PathIsWritable(const FilePath& path);
119 
120 // Returns true if the given path exists and is a directory, false otherwise.
121 BASE_EXPORT bool DirectoryExists(const FilePath& path);
122 
123 // Returns true if the contents of the two files given are equal, false
124 // otherwise.  If either file can't be read, returns false.
125 BASE_EXPORT bool ContentsEqual(const FilePath& filename1,
126                                const FilePath& filename2);
127 
128 // Returns true if the contents of the two text files given are equal, false
129 // otherwise.  This routine treats "\r\n" and "\n" as equivalent.
130 BASE_EXPORT bool TextContentsEqual(const FilePath& filename1,
131                                    const FilePath& filename2);
132 
133 // Read the file at |path| into |contents|, returning true on success.
134 // This function fails if the |path| contains path traversal components ('..').
135 // |contents| may be NULL, in which case this function is useful for its
136 // side effect of priming the disk cache.
137 // Useful for unit tests.
138 BASE_EXPORT bool ReadFileToString(const FilePath& path, std::string* contents);
139 
140 #if defined(OS_POSIX)
141 
142 // Read exactly |bytes| bytes from file descriptor |fd|, storing the result
143 // in |buffer|. This function is protected against EINTR and partial reads.
144 // Returns true iff |bytes| bytes have been successfully read from |fd|.
145 BASE_EXPORT bool ReadFromFD(int fd, char* buffer, size_t bytes);
146 
147 // Creates a symbolic link at |symlink| pointing to |target|.  Returns
148 // false on failure.
149 BASE_EXPORT bool CreateSymbolicLink(const FilePath& target,
150                                     const FilePath& symlink);
151 
152 // Reads the given |symlink| and returns where it points to in |target|.
153 // Returns false upon failure.
154 BASE_EXPORT bool ReadSymbolicLink(const FilePath& symlink, FilePath* target);
155 
156 // Bits ans masks of the file permission.
157 enum FilePermissionBits {
158   FILE_PERMISSION_MASK              = S_IRWXU | S_IRWXG | S_IRWXO,
159   FILE_PERMISSION_USER_MASK         = S_IRWXU,
160   FILE_PERMISSION_GROUP_MASK        = S_IRWXG,
161   FILE_PERMISSION_OTHERS_MASK       = S_IRWXO,
162 
163   FILE_PERMISSION_READ_BY_USER      = S_IRUSR,
164   FILE_PERMISSION_WRITE_BY_USER     = S_IWUSR,
165   FILE_PERMISSION_EXECUTE_BY_USER   = S_IXUSR,
166   FILE_PERMISSION_READ_BY_GROUP     = S_IRGRP,
167   FILE_PERMISSION_WRITE_BY_GROUP    = S_IWGRP,
168   FILE_PERMISSION_EXECUTE_BY_GROUP  = S_IXGRP,
169   FILE_PERMISSION_READ_BY_OTHERS    = S_IROTH,
170   FILE_PERMISSION_WRITE_BY_OTHERS   = S_IWOTH,
171   FILE_PERMISSION_EXECUTE_BY_OTHERS = S_IXOTH,
172 };
173 
174 // Reads the permission of the given |path|, storing the file permission
175 // bits in |mode|. If |path| is symbolic link, |mode| is the permission of
176 // a file which the symlink points to.
177 BASE_EXPORT bool GetPosixFilePermissions(const FilePath& path, int* mode);
178 // Sets the permission of the given |path|. If |path| is symbolic link, sets
179 // the permission of a file which the symlink points to.
180 BASE_EXPORT bool SetPosixFilePermissions(const FilePath& path, int mode);
181 
182 #endif  // OS_POSIX
183 
184 // Returns true if the given directory is empty
185 BASE_EXPORT bool IsDirectoryEmpty(const FilePath& dir_path);
186 
187 // Get the temporary directory provided by the system.
188 //
189 // WARNING: In general, you should use CreateTemporaryFile variants below
190 // instead of this function. Those variants will ensure that the proper
191 // permissions are set so that other users on the system can't edit them while
192 // they're open (which can lead to security issues).
193 BASE_EXPORT bool GetTempDir(FilePath* path);
194 
195 // Get a temporary directory for shared memory files. The directory may depend
196 // on whether the destination is intended for executable files, which in turn
197 // depends on how /dev/shmem was mounted. As a result, you must supply whether
198 // you intend to create executable shmem segments so this function can find
199 // an appropriate location.
200 //
201 // Only useful on POSIX; redirects to GetTempDir() on Windows.
202 BASE_EXPORT bool GetShmemTempDir(bool executable, FilePath* path);
203 
204 #if defined(OS_POSIX)
205 // Get the home directory.  This is more complicated than just getenv("HOME")
206 // as it knows to fall back on getpwent() etc.
207 //
208 // This function is not currently implemented on Windows or Mac because we
209 // don't use it. Generally you would use one of PathService's APP_DATA
210 // directories on those platforms. If we need it, this could be implemented
211 // there to return the appropriate directory.
212 BASE_EXPORT FilePath GetHomeDir();
213 #endif  // OS_POSIX
214 
215 // Creates a temporary file. The full path is placed in |path|, and the
216 // function returns true if was successful in creating the file. The file will
217 // be empty and all handles closed after this function returns.
218 BASE_EXPORT bool CreateTemporaryFile(FilePath* path);
219 
220 // Same as CreateTemporaryFile but the file is created in |dir|.
221 BASE_EXPORT bool CreateTemporaryFileInDir(const FilePath& dir,
222                                           FilePath* temp_file);
223 
224 // Create and open a temporary file.  File is opened for read/write.
225 // The full path is placed in |path|.
226 // Returns a handle to the opened file or NULL if an error occurred.
227 BASE_EXPORT FILE* CreateAndOpenTemporaryFile(FilePath* path);
228 
229 // Like above but for shmem files.  Only useful for POSIX.
230 // The executable flag says the file needs to support using
231 // mprotect with PROT_EXEC after mapping.
232 BASE_EXPORT FILE* CreateAndOpenTemporaryShmemFile(FilePath* path,
233                                                   bool executable);
234 
235 // Similar to CreateAndOpenTemporaryFile, but the file is created in |dir|.
236 BASE_EXPORT FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir,
237                                                   FilePath* path);
238 
239 // Create a new directory. If prefix is provided, the new directory name is in
240 // the format of prefixyyyy.
241 // NOTE: prefix is ignored in the POSIX implementation.
242 // If success, return true and output the full path of the directory created.
243 BASE_EXPORT bool CreateNewTempDirectory(const FilePath::StringType& prefix,
244                                         FilePath* new_temp_path);
245 
246 // Create a directory within another directory.
247 // Extra characters will be appended to |prefix| to ensure that the
248 // new directory does not have the same name as an existing directory.
249 BASE_EXPORT bool CreateTemporaryDirInDir(const FilePath& base_dir,
250                                          const FilePath::StringType& prefix,
251                                          FilePath* new_dir);
252 
253 // Creates a directory, as well as creating any parent directories, if they
254 // don't exist. Returns 'true' on successful creation, or if the directory
255 // already exists.  The directory is only readable by the current user.
256 // Returns true on success, leaving *error unchanged.
257 // Returns false on failure and sets *error appropriately, if it is non-NULL.
258 BASE_EXPORT bool CreateDirectoryAndGetError(const FilePath& full_path,
259                                             PlatformFileError* error);
260 
261 // Backward-compatible convenience method for the above.
262 BASE_EXPORT bool CreateDirectory(const FilePath& full_path);
263 
264 // Returns the file size. Returns true on success.
265 BASE_EXPORT bool GetFileSize(const FilePath& file_path, int64* file_size);
266 
267 // Sets |real_path| to |path| with symbolic links and junctions expanded.
268 // On windows, make sure the path starts with a lettered drive.
269 // |path| must reference a file.  Function will fail if |path| points to
270 // a directory or to a nonexistent path.  On windows, this function will
271 // fail if |path| is a junction or symlink that points to an empty file,
272 // or if |real_path| would be longer than MAX_PATH characters.
273 BASE_EXPORT bool NormalizeFilePath(const FilePath& path, FilePath* real_path);
274 
275 #if defined(OS_WIN)
276 
277 // Given a path in NT native form ("\Device\HarddiskVolumeXX\..."),
278 // return in |drive_letter_path| the equivalent path that starts with
279 // a drive letter ("C:\...").  Return false if no such path exists.
280 BASE_EXPORT bool DevicePathToDriveLetterPath(const FilePath& device_path,
281                                              FilePath* drive_letter_path);
282 
283 // Given an existing file in |path|, set |real_path| to the path
284 // in native NT format, of the form "\Device\HarddiskVolumeXX\..".
285 // Returns false if the path can not be found. Empty files cannot
286 // be resolved with this function.
287 BASE_EXPORT bool NormalizeToNativeFilePath(const FilePath& path,
288                                            FilePath* nt_path);
289 #endif
290 
291 // This function will return if the given file is a symlink or not.
292 BASE_EXPORT bool IsLink(const FilePath& file_path);
293 
294 // Returns information about the given file path.
295 BASE_EXPORT bool GetFileInfo(const FilePath& file_path, PlatformFileInfo* info);
296 
297 // Sets the time of the last access and the time of the last modification.
298 BASE_EXPORT bool TouchFile(const FilePath& path,
299                            const Time& last_accessed,
300                            const Time& last_modified);
301 
302 // Wrapper for fopen-like calls. Returns non-NULL FILE* on success.
303 BASE_EXPORT FILE* OpenFile(const FilePath& filename, const char* mode);
304 
305 // Closes file opened by OpenFile. Returns true on success.
306 BASE_EXPORT bool CloseFile(FILE* file);
307 
308 // Truncates an open file to end at the location of the current file pointer.
309 // This is a cross-platform analog to Windows' SetEndOfFile() function.
310 BASE_EXPORT bool TruncateFile(FILE* file);
311 
312 // Reads the given number of bytes from the file into the buffer.  Returns
313 // the number of read bytes, or -1 on error.
314 BASE_EXPORT int ReadFile(const base::FilePath& filename, char* data, int size);
315 
316 }  // namespace base
317 
318 // -----------------------------------------------------------------------------
319 
320 namespace file_util {
321 
322 // Writes the given buffer into the file, overwriting any data that was
323 // previously there.  Returns the number of bytes written, or -1 on error.
324 BASE_EXPORT int WriteFile(const base::FilePath& filename, const char* data,
325                           int size);
326 #if defined(OS_POSIX)
327 // Append the data to |fd|. Does not close |fd| when done.
328 BASE_EXPORT int WriteFileDescriptor(const int fd, const char* data, int size);
329 #endif
330 // Append the given buffer into the file. Returns the number of bytes written,
331 // or -1 on error.
332 BASE_EXPORT int AppendToFile(const base::FilePath& filename,
333                              const char* data, int size);
334 
335 // Gets the current working directory for the process.
336 BASE_EXPORT bool GetCurrentDirectory(base::FilePath* path);
337 
338 // Sets the current working directory for the process.
339 BASE_EXPORT bool SetCurrentDirectory(const base::FilePath& path);
340 
341 // Attempts to find a number that can be appended to the |path| to make it
342 // unique. If |path| does not exist, 0 is returned.  If it fails to find such
343 // a number, -1 is returned. If |suffix| is not empty, also checks the
344 // existence of it with the given suffix.
345 BASE_EXPORT int GetUniquePathNumber(const base::FilePath& path,
346                                     const base::FilePath::StringType& suffix);
347 
348 #if defined(OS_POSIX)
349 // Creates a directory with a guaranteed unique name based on |path|, returning
350 // the pathname if successful, or an empty path if there was an error creating
351 // the directory. Does not create parent directories.
352 BASE_EXPORT base::FilePath MakeUniqueDirectory(const base::FilePath& path);
353 #endif
354 
355 #if defined(OS_POSIX)
356 // Test that |path| can only be changed by a given user and members of
357 // a given set of groups.
358 // Specifically, test that all parts of |path| under (and including) |base|:
359 // * Exist.
360 // * Are owned by a specific user.
361 // * Are not writable by all users.
362 // * Are owned by a member of a given set of groups, or are not writable by
363 //   their group.
364 // * Are not symbolic links.
365 // This is useful for checking that a config file is administrator-controlled.
366 // |base| must contain |path|.
367 BASE_EXPORT bool VerifyPathControlledByUser(const base::FilePath& base,
368                                             const base::FilePath& path,
369                                             uid_t owner_uid,
370                                             const std::set<gid_t>& group_gids);
371 #endif  // defined(OS_POSIX)
372 
373 #if defined(OS_MACOSX) && !defined(OS_IOS)
374 // Is |path| writable only by a user with administrator privileges?
375 // This function uses Mac OS conventions.  The super user is assumed to have
376 // uid 0, and the administrator group is assumed to be named "admin".
377 // Testing that |path|, and every parent directory including the root of
378 // the filesystem, are owned by the superuser, controlled by the group
379 // "admin", are not writable by all users, and contain no symbolic links.
380 // Will return false if |path| does not exist.
381 BASE_EXPORT bool VerifyPathControlledByAdmin(const base::FilePath& path);
382 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
383 
384 // Returns the maximum length of path component on the volume containing
385 // the directory |path|, in the number of FilePath::CharType, or -1 on failure.
386 BASE_EXPORT int GetMaximumPathComponentLength(const base::FilePath& path);
387 
388 // A class to handle auto-closing of FILE*'s.
389 class ScopedFILEClose {
390  public:
operator()391   inline void operator()(FILE* x) const {
392     if (x) {
393       fclose(x);
394     }
395   }
396 };
397 
398 typedef scoped_ptr_malloc<FILE, ScopedFILEClose> ScopedFILE;
399 
400 #if defined(OS_POSIX)
401 // A class to handle auto-closing of FDs.
402 class ScopedFDClose {
403  public:
operator()404   inline void operator()(int* x) const {
405     if (x && *x >= 0) {
406       if (IGNORE_EINTR(close(*x)) < 0)
407         DPLOG(ERROR) << "close";
408     }
409   }
410 };
411 
412 typedef scoped_ptr_malloc<int, ScopedFDClose> ScopedFD;
413 #endif  // OS_POSIX
414 
415 #if defined(OS_LINUX)
416 // Broad categories of file systems as returned by statfs() on Linux.
417 enum FileSystemType {
418   FILE_SYSTEM_UNKNOWN,  // statfs failed.
419   FILE_SYSTEM_0,        // statfs.f_type == 0 means unknown, may indicate AFS.
420   FILE_SYSTEM_ORDINARY,       // on-disk filesystem like ext2
421   FILE_SYSTEM_NFS,
422   FILE_SYSTEM_SMB,
423   FILE_SYSTEM_CODA,
424   FILE_SYSTEM_MEMORY,         // in-memory file system
425   FILE_SYSTEM_CGROUP,         // cgroup control.
426   FILE_SYSTEM_OTHER,          // any other value.
427   FILE_SYSTEM_TYPE_COUNT
428 };
429 
430 // Attempts determine the FileSystemType for |path|.
431 // Returns false if |path| doesn't exist.
432 BASE_EXPORT bool GetFileSystemType(const base::FilePath& path,
433                                    FileSystemType* type);
434 #endif
435 
436 }  // namespace file_util
437 
438 // Internal --------------------------------------------------------------------
439 
440 namespace base {
441 namespace internal {
442 
443 // Same as Move but allows paths with traversal components.
444 // Use only with extreme care.
445 BASE_EXPORT bool MoveUnsafe(const FilePath& from_path,
446                             const FilePath& to_path);
447 
448 // Same as CopyFile but allows paths with traversal components.
449 // Use only with extreme care.
450 BASE_EXPORT bool CopyFileUnsafe(const FilePath& from_path,
451                                 const FilePath& to_path);
452 
453 #if defined(OS_WIN)
454 // Copy from_path to to_path recursively and then delete from_path recursively.
455 // Returns true if all operations succeed.
456 // This function simulates Move(), but unlike Move() it works across volumes.
457 // This function is not transactional.
458 BASE_EXPORT bool CopyAndDeleteDirectory(const FilePath& from_path,
459                                         const FilePath& to_path);
460 #endif  // defined(OS_WIN)
461 
462 }  // namespace internal
463 }  // namespace base
464 
465 #endif  // BASE_FILE_UTIL_H_
466