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 "base/file_util.h" 6 7 #include <windows.h> 8 #include <psapi.h> 9 #include <shellapi.h> 10 #include <shlobj.h> 11 #include <time.h> 12 13 #include <algorithm> 14 #include <limits> 15 #include <string> 16 17 #include "base/files/file_path.h" 18 #include "base/logging.h" 19 #include "base/metrics/histogram.h" 20 #include "base/process/process_handle.h" 21 #include "base/rand_util.h" 22 #include "base/strings/string_number_conversions.h" 23 #include "base/strings/string_util.h" 24 #include "base/strings/utf_string_conversions.h" 25 #include "base/threading/thread_restrictions.h" 26 #include "base/time/time.h" 27 #include "base/win/scoped_handle.h" 28 #include "base/win/windows_version.h" 29 30 namespace base { 31 32 namespace { 33 34 const DWORD kFileShareAll = 35 FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE; 36 37 bool ShellCopy(const FilePath& from_path, 38 const FilePath& to_path, 39 bool recursive) { 40 // WinXP SHFileOperation doesn't like trailing separators. 41 FilePath stripped_from = from_path.StripTrailingSeparators(); 42 FilePath stripped_to = to_path.StripTrailingSeparators(); 43 44 ThreadRestrictions::AssertIOAllowed(); 45 46 // NOTE: I suspect we could support longer paths, but that would involve 47 // analyzing all our usage of files. 48 if (stripped_from.value().length() >= MAX_PATH || 49 stripped_to.value().length() >= MAX_PATH) { 50 return false; 51 } 52 53 // SHFILEOPSTRUCT wants the path to be terminated with two NULLs, 54 // so we have to use wcscpy because wcscpy_s writes non-NULLs 55 // into the rest of the buffer. 56 wchar_t double_terminated_path_from[MAX_PATH + 1] = {0}; 57 wchar_t double_terminated_path_to[MAX_PATH + 1] = {0}; 58 #pragma warning(suppress:4996) // don't complain about wcscpy deprecation 59 wcscpy(double_terminated_path_from, stripped_from.value().c_str()); 60 #pragma warning(suppress:4996) // don't complain about wcscpy deprecation 61 wcscpy(double_terminated_path_to, stripped_to.value().c_str()); 62 63 SHFILEOPSTRUCT file_operation = {0}; 64 file_operation.wFunc = FO_COPY; 65 file_operation.pFrom = double_terminated_path_from; 66 file_operation.pTo = double_terminated_path_to; 67 file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION | 68 FOF_NOCONFIRMMKDIR; 69 if (!recursive) 70 file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY; 71 72 return (SHFileOperation(&file_operation) == 0); 73 } 74 75 } // namespace 76 77 FilePath MakeAbsoluteFilePath(const FilePath& input) { 78 ThreadRestrictions::AssertIOAllowed(); 79 wchar_t file_path[MAX_PATH]; 80 if (!_wfullpath(file_path, input.value().c_str(), MAX_PATH)) 81 return FilePath(); 82 return FilePath(file_path); 83 } 84 85 bool DeleteFile(const FilePath& path, bool recursive) { 86 ThreadRestrictions::AssertIOAllowed(); 87 88 if (path.value().length() >= MAX_PATH) 89 return false; 90 91 if (!recursive) { 92 // If not recursing, then first check to see if |path| is a directory. 93 // If it is, then remove it with RemoveDirectory. 94 PlatformFileInfo file_info; 95 if (GetFileInfo(path, &file_info) && file_info.is_directory) 96 return RemoveDirectory(path.value().c_str()) != 0; 97 98 // Otherwise, it's a file, wildcard or non-existant. Try DeleteFile first 99 // because it should be faster. If DeleteFile fails, then we fall through 100 // to SHFileOperation, which will do the right thing. 101 if (::DeleteFile(path.value().c_str()) != 0) 102 return true; 103 } 104 105 // SHFILEOPSTRUCT wants the path to be terminated with two NULLs, 106 // so we have to use wcscpy because wcscpy_s writes non-NULLs 107 // into the rest of the buffer. 108 wchar_t double_terminated_path[MAX_PATH + 1] = {0}; 109 #pragma warning(suppress:4996) // don't complain about wcscpy deprecation 110 wcscpy(double_terminated_path, path.value().c_str()); 111 112 SHFILEOPSTRUCT file_operation = {0}; 113 file_operation.wFunc = FO_DELETE; 114 file_operation.pFrom = double_terminated_path; 115 file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION; 116 if (!recursive) 117 file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY; 118 int err = SHFileOperation(&file_operation); 119 120 // Since we're passing flags to the operation telling it to be silent, 121 // it's possible for the operation to be aborted/cancelled without err 122 // being set (although MSDN doesn't give any scenarios for how this can 123 // happen). See MSDN for SHFileOperation and SHFILEOPTSTRUCT. 124 if (file_operation.fAnyOperationsAborted) 125 return false; 126 127 // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting 128 // an empty directory and some return 0x402 when they should be returning 129 // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402. 130 return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402); 131 } 132 133 bool DeleteFileAfterReboot(const FilePath& path) { 134 ThreadRestrictions::AssertIOAllowed(); 135 136 if (path.value().length() >= MAX_PATH) 137 return false; 138 139 return MoveFileEx(path.value().c_str(), NULL, 140 MOVEFILE_DELAY_UNTIL_REBOOT | 141 MOVEFILE_REPLACE_EXISTING) != FALSE; 142 } 143 144 bool ReplaceFile(const FilePath& from_path, 145 const FilePath& to_path, 146 PlatformFileError* error) { 147 ThreadRestrictions::AssertIOAllowed(); 148 // Try a simple move first. It will only succeed when |to_path| doesn't 149 // already exist. 150 if (::MoveFile(from_path.value().c_str(), to_path.value().c_str())) 151 return true; 152 // Try the full-blown replace if the move fails, as ReplaceFile will only 153 // succeed when |to_path| does exist. When writing to a network share, we may 154 // not be able to change the ACLs. Ignore ACL errors then 155 // (REPLACEFILE_IGNORE_MERGE_ERRORS). 156 if (::ReplaceFile(to_path.value().c_str(), from_path.value().c_str(), NULL, 157 REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL)) { 158 return true; 159 } 160 if (error) 161 *error = LastErrorToPlatformFileError(GetLastError()); 162 return false; 163 } 164 165 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path, 166 bool recursive) { 167 ThreadRestrictions::AssertIOAllowed(); 168 169 if (recursive) 170 return ShellCopy(from_path, to_path, true); 171 172 // The following code assumes that from path is a directory. 173 DCHECK(DirectoryExists(from_path)); 174 175 // Instead of creating a new directory, we copy the old one to include the 176 // security information of the folder as part of the copy. 177 if (!PathExists(to_path)) { 178 // Except that Vista fails to do that, and instead do a recursive copy if 179 // the target directory doesn't exist. 180 if (base::win::GetVersion() >= base::win::VERSION_VISTA) 181 CreateDirectory(to_path); 182 else 183 ShellCopy(from_path, to_path, false); 184 } 185 186 FilePath directory = from_path.Append(L"*.*"); 187 return ShellCopy(directory, to_path, false); 188 } 189 190 bool PathExists(const FilePath& path) { 191 ThreadRestrictions::AssertIOAllowed(); 192 return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES); 193 } 194 195 bool PathIsWritable(const FilePath& path) { 196 ThreadRestrictions::AssertIOAllowed(); 197 HANDLE dir = 198 CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll, 199 NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL); 200 201 if (dir == INVALID_HANDLE_VALUE) 202 return false; 203 204 CloseHandle(dir); 205 return true; 206 } 207 208 bool DirectoryExists(const FilePath& path) { 209 ThreadRestrictions::AssertIOAllowed(); 210 DWORD fileattr = GetFileAttributes(path.value().c_str()); 211 if (fileattr != INVALID_FILE_ATTRIBUTES) 212 return (fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0; 213 return false; 214 } 215 216 bool GetTempDir(FilePath* path) { 217 wchar_t temp_path[MAX_PATH + 1]; 218 DWORD path_len = ::GetTempPath(MAX_PATH, temp_path); 219 if (path_len >= MAX_PATH || path_len <= 0) 220 return false; 221 // TODO(evanm): the old behavior of this function was to always strip the 222 // trailing slash. We duplicate this here, but it shouldn't be necessary 223 // when everyone is using the appropriate FilePath APIs. 224 *path = FilePath(temp_path).StripTrailingSeparators(); 225 return true; 226 } 227 228 bool GetShmemTempDir(bool executable, FilePath* path) { 229 return GetTempDir(path); 230 } 231 232 bool CreateTemporaryFile(FilePath* path) { 233 ThreadRestrictions::AssertIOAllowed(); 234 235 FilePath temp_file; 236 237 if (!GetTempDir(path)) 238 return false; 239 240 if (CreateTemporaryFileInDir(*path, &temp_file)) { 241 *path = temp_file; 242 return true; 243 } 244 245 return false; 246 } 247 248 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) { 249 ThreadRestrictions::AssertIOAllowed(); 250 return CreateAndOpenTemporaryFile(path); 251 } 252 253 // On POSIX we have semantics to create and open a temporary file 254 // atomically. 255 // TODO(jrg): is there equivalent call to use on Windows instead of 256 // going 2-step? 257 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) { 258 ThreadRestrictions::AssertIOAllowed(); 259 if (!CreateTemporaryFileInDir(dir, path)) { 260 return NULL; 261 } 262 // Open file in binary mode, to avoid problems with fwrite. On Windows 263 // it replaces \n's with \r\n's, which may surprise you. 264 // Reference: http://msdn.microsoft.com/en-us/library/h9t88zwz(VS.71).aspx 265 return OpenFile(*path, "wb+"); 266 } 267 268 bool CreateTemporaryFileInDir(const FilePath& dir, FilePath* temp_file) { 269 ThreadRestrictions::AssertIOAllowed(); 270 271 wchar_t temp_name[MAX_PATH + 1]; 272 273 if (!GetTempFileName(dir.value().c_str(), L"", 0, temp_name)) { 274 DPLOG(WARNING) << "Failed to get temporary file name in " 275 << UTF16ToUTF8(dir.value()); 276 return false; 277 } 278 279 wchar_t long_temp_name[MAX_PATH + 1]; 280 DWORD long_name_len = GetLongPathName(temp_name, long_temp_name, MAX_PATH); 281 if (long_name_len > MAX_PATH || long_name_len == 0) { 282 // GetLongPathName() failed, but we still have a temporary file. 283 *temp_file = FilePath(temp_name); 284 return true; 285 } 286 287 FilePath::StringType long_temp_name_str; 288 long_temp_name_str.assign(long_temp_name, long_name_len); 289 *temp_file = FilePath(long_temp_name_str); 290 return true; 291 } 292 293 bool CreateTemporaryDirInDir(const FilePath& base_dir, 294 const FilePath::StringType& prefix, 295 FilePath* new_dir) { 296 ThreadRestrictions::AssertIOAllowed(); 297 298 FilePath path_to_create; 299 300 for (int count = 0; count < 50; ++count) { 301 // Try create a new temporary directory with random generated name. If 302 // the one exists, keep trying another path name until we reach some limit. 303 string16 new_dir_name; 304 new_dir_name.assign(prefix); 305 new_dir_name.append(IntToString16(GetCurrentProcId())); 306 new_dir_name.push_back('_'); 307 new_dir_name.append(IntToString16(RandInt(0, kint16max))); 308 309 path_to_create = base_dir.Append(new_dir_name); 310 if (::CreateDirectory(path_to_create.value().c_str(), NULL)) { 311 *new_dir = path_to_create; 312 return true; 313 } 314 } 315 316 return false; 317 } 318 319 bool CreateNewTempDirectory(const FilePath::StringType& prefix, 320 FilePath* new_temp_path) { 321 ThreadRestrictions::AssertIOAllowed(); 322 323 FilePath system_temp_dir; 324 if (!GetTempDir(&system_temp_dir)) 325 return false; 326 327 return CreateTemporaryDirInDir(system_temp_dir, prefix, new_temp_path); 328 } 329 330 bool CreateDirectoryAndGetError(const FilePath& full_path, 331 PlatformFileError* error) { 332 ThreadRestrictions::AssertIOAllowed(); 333 334 // If the path exists, we've succeeded if it's a directory, failed otherwise. 335 const wchar_t* full_path_str = full_path.value().c_str(); 336 DWORD fileattr = ::GetFileAttributes(full_path_str); 337 if (fileattr != INVALID_FILE_ATTRIBUTES) { 338 if ((fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0) { 339 DVLOG(1) << "CreateDirectory(" << full_path_str << "), " 340 << "directory already exists."; 341 return true; 342 } 343 DLOG(WARNING) << "CreateDirectory(" << full_path_str << "), " 344 << "conflicts with existing file."; 345 if (error) { 346 *error = PLATFORM_FILE_ERROR_NOT_A_DIRECTORY; 347 } 348 return false; 349 } 350 351 // Invariant: Path does not exist as file or directory. 352 353 // Attempt to create the parent recursively. This will immediately return 354 // true if it already exists, otherwise will create all required parent 355 // directories starting with the highest-level missing parent. 356 FilePath parent_path(full_path.DirName()); 357 if (parent_path.value() == full_path.value()) { 358 if (error) { 359 *error = PLATFORM_FILE_ERROR_NOT_FOUND; 360 } 361 return false; 362 } 363 if (!CreateDirectoryAndGetError(parent_path, error)) { 364 DLOG(WARNING) << "Failed to create one of the parent directories."; 365 if (error) { 366 DCHECK(*error != PLATFORM_FILE_OK); 367 } 368 return false; 369 } 370 371 if (!::CreateDirectory(full_path_str, NULL)) { 372 DWORD error_code = ::GetLastError(); 373 if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) { 374 // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we 375 // were racing with someone creating the same directory, or a file 376 // with the same path. If DirectoryExists() returns true, we lost the 377 // race to create the same directory. 378 return true; 379 } else { 380 if (error) 381 *error = LastErrorToPlatformFileError(error_code); 382 DLOG(WARNING) << "Failed to create directory " << full_path_str 383 << ", last error is " << error_code << "."; 384 return false; 385 } 386 } else { 387 return true; 388 } 389 } 390 391 bool NormalizeFilePath(const FilePath& path, FilePath* real_path) { 392 ThreadRestrictions::AssertIOAllowed(); 393 FilePath mapped_file; 394 if (!NormalizeToNativeFilePath(path, &mapped_file)) 395 return false; 396 // NormalizeToNativeFilePath() will return a path that starts with 397 // "\Device\Harddisk...". Helper DevicePathToDriveLetterPath() 398 // will find a drive letter which maps to the path's device, so 399 // that we return a path starting with a drive letter. 400 return DevicePathToDriveLetterPath(mapped_file, real_path); 401 } 402 403 bool DevicePathToDriveLetterPath(const FilePath& nt_device_path, 404 FilePath* out_drive_letter_path) { 405 ThreadRestrictions::AssertIOAllowed(); 406 407 // Get the mapping of drive letters to device paths. 408 const int kDriveMappingSize = 1024; 409 wchar_t drive_mapping[kDriveMappingSize] = {'\0'}; 410 if (!::GetLogicalDriveStrings(kDriveMappingSize - 1, drive_mapping)) { 411 DLOG(ERROR) << "Failed to get drive mapping."; 412 return false; 413 } 414 415 // The drive mapping is a sequence of null terminated strings. 416 // The last string is empty. 417 wchar_t* drive_map_ptr = drive_mapping; 418 wchar_t device_path_as_string[MAX_PATH]; 419 wchar_t drive[] = L" :"; 420 421 // For each string in the drive mapping, get the junction that links 422 // to it. If that junction is a prefix of |device_path|, then we 423 // know that |drive| is the real path prefix. 424 while (*drive_map_ptr) { 425 drive[0] = drive_map_ptr[0]; // Copy the drive letter. 426 427 if (QueryDosDevice(drive, device_path_as_string, MAX_PATH)) { 428 FilePath device_path(device_path_as_string); 429 if (device_path == nt_device_path || 430 device_path.IsParent(nt_device_path)) { 431 *out_drive_letter_path = FilePath(drive + 432 nt_device_path.value().substr(wcslen(device_path_as_string))); 433 return true; 434 } 435 } 436 // Move to the next drive letter string, which starts one 437 // increment after the '\0' that terminates the current string. 438 while (*drive_map_ptr++); 439 } 440 441 // No drive matched. The path does not start with a device junction 442 // that is mounted as a drive letter. This means there is no drive 443 // letter path to the volume that holds |device_path|, so fail. 444 return false; 445 } 446 447 bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path) { 448 ThreadRestrictions::AssertIOAllowed(); 449 // In Vista, GetFinalPathNameByHandle() would give us the real path 450 // from a file handle. If we ever deprecate XP, consider changing the 451 // code below to a call to GetFinalPathNameByHandle(). The method this 452 // function uses is explained in the following msdn article: 453 // http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx 454 base::win::ScopedHandle file_handle( 455 ::CreateFile(path.value().c_str(), 456 GENERIC_READ, 457 kFileShareAll, 458 NULL, 459 OPEN_EXISTING, 460 FILE_ATTRIBUTE_NORMAL, 461 NULL)); 462 if (!file_handle) 463 return false; 464 465 // Create a file mapping object. Can't easily use MemoryMappedFile, because 466 // we only map the first byte, and need direct access to the handle. You can 467 // not map an empty file, this call fails in that case. 468 base::win::ScopedHandle file_map_handle( 469 ::CreateFileMapping(file_handle.Get(), 470 NULL, 471 PAGE_READONLY, 472 0, 473 1, // Just one byte. No need to look at the data. 474 NULL)); 475 if (!file_map_handle) 476 return false; 477 478 // Use a view of the file to get the path to the file. 479 void* file_view = MapViewOfFile(file_map_handle.Get(), 480 FILE_MAP_READ, 0, 0, 1); 481 if (!file_view) 482 return false; 483 484 // The expansion of |path| into a full path may make it longer. 485 // GetMappedFileName() will fail if the result is longer than MAX_PATH. 486 // Pad a bit to be safe. If kMaxPathLength is ever changed to be less 487 // than MAX_PATH, it would be nessisary to test that GetMappedFileName() 488 // not return kMaxPathLength. This would mean that only part of the 489 // path fit in |mapped_file_path|. 490 const int kMaxPathLength = MAX_PATH + 10; 491 wchar_t mapped_file_path[kMaxPathLength]; 492 bool success = false; 493 HANDLE cp = GetCurrentProcess(); 494 if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) { 495 *nt_path = FilePath(mapped_file_path); 496 success = true; 497 } 498 ::UnmapViewOfFile(file_view); 499 return success; 500 } 501 502 // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle 503 // them if we do decide to. 504 bool IsLink(const FilePath& file_path) { 505 return false; 506 } 507 508 bool GetFileInfo(const FilePath& file_path, PlatformFileInfo* results) { 509 ThreadRestrictions::AssertIOAllowed(); 510 511 WIN32_FILE_ATTRIBUTE_DATA attr; 512 if (!GetFileAttributesEx(file_path.value().c_str(), 513 GetFileExInfoStandard, &attr)) { 514 return false; 515 } 516 517 ULARGE_INTEGER size; 518 size.HighPart = attr.nFileSizeHigh; 519 size.LowPart = attr.nFileSizeLow; 520 results->size = size.QuadPart; 521 522 results->is_directory = 523 (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0; 524 results->last_modified = Time::FromFileTime(attr.ftLastWriteTime); 525 results->last_accessed = Time::FromFileTime(attr.ftLastAccessTime); 526 results->creation_time = Time::FromFileTime(attr.ftCreationTime); 527 528 return true; 529 } 530 531 FILE* OpenFile(const FilePath& filename, const char* mode) { 532 ThreadRestrictions::AssertIOAllowed(); 533 std::wstring w_mode = ASCIIToWide(std::string(mode)); 534 return _wfsopen(filename.value().c_str(), w_mode.c_str(), _SH_DENYNO); 535 } 536 537 int ReadFile(const FilePath& filename, char* data, int size) { 538 ThreadRestrictions::AssertIOAllowed(); 539 base::win::ScopedHandle file(CreateFile(filename.value().c_str(), 540 GENERIC_READ, 541 FILE_SHARE_READ | FILE_SHARE_WRITE, 542 NULL, 543 OPEN_EXISTING, 544 FILE_FLAG_SEQUENTIAL_SCAN, 545 NULL)); 546 if (!file) 547 return -1; 548 549 DWORD read; 550 if (::ReadFile(file, data, size, &read, NULL) && 551 static_cast<int>(read) == size) 552 return read; 553 return -1; 554 } 555 556 } // namespace base 557 558 // ----------------------------------------------------------------------------- 559 560 namespace file_util { 561 562 using base::DirectoryExists; 563 using base::FilePath; 564 using base::kFileShareAll; 565 566 FILE* OpenFile(const std::string& filename, const char* mode) { 567 base::ThreadRestrictions::AssertIOAllowed(); 568 return _fsopen(filename.c_str(), mode, _SH_DENYNO); 569 } 570 571 int WriteFile(const FilePath& filename, const char* data, int size) { 572 base::ThreadRestrictions::AssertIOAllowed(); 573 base::win::ScopedHandle file(CreateFile(filename.value().c_str(), 574 GENERIC_WRITE, 575 0, 576 NULL, 577 CREATE_ALWAYS, 578 0, 579 NULL)); 580 if (!file) { 581 DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path " 582 << filename.value(); 583 return -1; 584 } 585 586 DWORD written; 587 BOOL result = ::WriteFile(file, data, size, &written, NULL); 588 if (result && static_cast<int>(written) == size) 589 return written; 590 591 if (!result) { 592 // WriteFile failed. 593 DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value() 594 << " failed"; 595 } else { 596 // Didn't write all the bytes. 597 DLOG(WARNING) << "wrote" << written << " bytes to " 598 << filename.value() << " expected " << size; 599 } 600 return -1; 601 } 602 603 int AppendToFile(const FilePath& filename, const char* data, int size) { 604 base::ThreadRestrictions::AssertIOAllowed(); 605 base::win::ScopedHandle file(CreateFile(filename.value().c_str(), 606 FILE_APPEND_DATA, 607 0, 608 NULL, 609 OPEN_EXISTING, 610 0, 611 NULL)); 612 if (!file) { 613 DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path " 614 << filename.value(); 615 return -1; 616 } 617 618 DWORD written; 619 BOOL result = ::WriteFile(file, data, size, &written, NULL); 620 if (result && static_cast<int>(written) == size) 621 return written; 622 623 if (!result) { 624 // WriteFile failed. 625 DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value() 626 << " failed"; 627 } else { 628 // Didn't write all the bytes. 629 DLOG(WARNING) << "wrote" << written << " bytes to " 630 << filename.value() << " expected " << size; 631 } 632 return -1; 633 } 634 635 // Gets the current working directory for the process. 636 bool GetCurrentDirectory(FilePath* dir) { 637 base::ThreadRestrictions::AssertIOAllowed(); 638 639 wchar_t system_buffer[MAX_PATH]; 640 system_buffer[0] = 0; 641 DWORD len = ::GetCurrentDirectory(MAX_PATH, system_buffer); 642 if (len == 0 || len > MAX_PATH) 643 return false; 644 // TODO(evanm): the old behavior of this function was to always strip the 645 // trailing slash. We duplicate this here, but it shouldn't be necessary 646 // when everyone is using the appropriate FilePath APIs. 647 std::wstring dir_str(system_buffer); 648 *dir = FilePath(dir_str).StripTrailingSeparators(); 649 return true; 650 } 651 652 // Sets the current working directory for the process. 653 bool SetCurrentDirectory(const FilePath& directory) { 654 base::ThreadRestrictions::AssertIOAllowed(); 655 BOOL ret = ::SetCurrentDirectory(directory.value().c_str()); 656 return ret != 0; 657 } 658 659 int GetMaximumPathComponentLength(const FilePath& path) { 660 base::ThreadRestrictions::AssertIOAllowed(); 661 662 wchar_t volume_path[MAX_PATH]; 663 if (!GetVolumePathNameW(path.NormalizePathSeparators().value().c_str(), 664 volume_path, 665 arraysize(volume_path))) { 666 return -1; 667 } 668 669 DWORD max_length = 0; 670 if (!GetVolumeInformationW(volume_path, NULL, 0, NULL, &max_length, NULL, 671 NULL, 0)) { 672 return -1; 673 } 674 675 // Length of |path| with path separator appended. 676 size_t prefix = path.StripTrailingSeparators().value().size() + 1; 677 // The whole path string must be shorter than MAX_PATH. That is, it must be 678 // prefix + component_length < MAX_PATH (or equivalently, <= MAX_PATH - 1). 679 int whole_path_limit = std::max(0, MAX_PATH - 1 - static_cast<int>(prefix)); 680 return std::min(whole_path_limit, static_cast<int>(max_length)); 681 } 682 683 } // namespace file_util 684 685 namespace base { 686 namespace internal { 687 688 bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) { 689 ThreadRestrictions::AssertIOAllowed(); 690 691 // NOTE: I suspect we could support longer paths, but that would involve 692 // analyzing all our usage of files. 693 if (from_path.value().length() >= MAX_PATH || 694 to_path.value().length() >= MAX_PATH) { 695 return false; 696 } 697 if (MoveFileEx(from_path.value().c_str(), to_path.value().c_str(), 698 MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING) != 0) 699 return true; 700 701 // Keep the last error value from MoveFileEx around in case the below 702 // fails. 703 bool ret = false; 704 DWORD last_error = ::GetLastError(); 705 706 if (DirectoryExists(from_path)) { 707 // MoveFileEx fails if moving directory across volumes. We will simulate 708 // the move by using Copy and Delete. Ideally we could check whether 709 // from_path and to_path are indeed in different volumes. 710 ret = internal::CopyAndDeleteDirectory(from_path, to_path); 711 } 712 713 if (!ret) { 714 // Leave a clue about what went wrong so that it can be (at least) picked 715 // up by a PLOG entry. 716 ::SetLastError(last_error); 717 } 718 719 return ret; 720 } 721 722 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) { 723 ThreadRestrictions::AssertIOAllowed(); 724 725 // NOTE: I suspect we could support longer paths, but that would involve 726 // analyzing all our usage of files. 727 if (from_path.value().length() >= MAX_PATH || 728 to_path.value().length() >= MAX_PATH) { 729 return false; 730 } 731 return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(), 732 false) != 0); 733 } 734 735 bool CopyAndDeleteDirectory(const FilePath& from_path, 736 const FilePath& to_path) { 737 ThreadRestrictions::AssertIOAllowed(); 738 if (CopyDirectory(from_path, to_path, true)) { 739 if (DeleteFile(from_path, true)) 740 return true; 741 742 // Like Move, this function is not transactional, so we just 743 // leave the copied bits behind if deleting from_path fails. 744 // If to_path exists previously then we have already overwritten 745 // it by now, we don't get better off by deleting the new bits. 746 } 747 return false; 748 } 749 750 } // namespace internal 751 } // namespace base 752
