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 (file_util::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 if (g_bug108724_debug) 111 LOG(WARNING) << "copying "; 112 wcscpy(double_terminated_path, path.value().c_str()); 113 114 SHFILEOPSTRUCT file_operation = {0}; 115 file_operation.wFunc = FO_DELETE; 116 file_operation.pFrom = double_terminated_path; 117 file_operation.fFlags = FOF_NOERRORUI | FOF_SILENT | FOF_NOCONFIRMATION; 118 if (!recursive) 119 file_operation.fFlags |= FOF_NORECURSION | FOF_FILESONLY; 120 if (g_bug108724_debug) 121 LOG(WARNING) << "Performing shell operation"; 122 int err = SHFileOperation(&file_operation); 123 if (g_bug108724_debug) 124 LOG(WARNING) << "Done: " << err; 125 126 // Since we're passing flags to the operation telling it to be silent, 127 // it's possible for the operation to be aborted/cancelled without err 128 // being set (although MSDN doesn't give any scenarios for how this can 129 // happen). See MSDN for SHFileOperation and SHFILEOPTSTRUCT. 130 if (file_operation.fAnyOperationsAborted) 131 return false; 132 133 // Some versions of Windows return ERROR_FILE_NOT_FOUND (0x2) when deleting 134 // an empty directory and some return 0x402 when they should be returning 135 // ERROR_FILE_NOT_FOUND. MSDN says Vista and up won't return 0x402. 136 return (err == 0 || err == ERROR_FILE_NOT_FOUND || err == 0x402); 137 } 138 139 bool DeleteFileAfterReboot(const FilePath& path) { 140 ThreadRestrictions::AssertIOAllowed(); 141 142 if (path.value().length() >= MAX_PATH) 143 return false; 144 145 return MoveFileEx(path.value().c_str(), NULL, 146 MOVEFILE_DELAY_UNTIL_REBOOT | 147 MOVEFILE_REPLACE_EXISTING) != FALSE; 148 } 149 150 bool ReplaceFile(const FilePath& from_path, 151 const FilePath& to_path, 152 PlatformFileError* error) { 153 ThreadRestrictions::AssertIOAllowed(); 154 // Try a simple move first. It will only succeed when |to_path| doesn't 155 // already exist. 156 if (::MoveFile(from_path.value().c_str(), to_path.value().c_str())) 157 return true; 158 // Try the full-blown replace if the move fails, as ReplaceFile will only 159 // succeed when |to_path| does exist. When writing to a network share, we may 160 // not be able to change the ACLs. Ignore ACL errors then 161 // (REPLACEFILE_IGNORE_MERGE_ERRORS). 162 if (::ReplaceFile(to_path.value().c_str(), from_path.value().c_str(), NULL, 163 REPLACEFILE_IGNORE_MERGE_ERRORS, NULL, NULL)) { 164 return true; 165 } 166 if (error) 167 *error = LastErrorToPlatformFileError(GetLastError()); 168 return false; 169 } 170 171 bool CopyDirectory(const FilePath& from_path, const FilePath& to_path, 172 bool recursive) { 173 ThreadRestrictions::AssertIOAllowed(); 174 175 if (recursive) 176 return ShellCopy(from_path, to_path, true); 177 178 // The following code assumes that from path is a directory. 179 DCHECK(DirectoryExists(from_path)); 180 181 // Instead of creating a new directory, we copy the old one to include the 182 // security information of the folder as part of the copy. 183 if (!PathExists(to_path)) { 184 // Except that Vista fails to do that, and instead do a recursive copy if 185 // the target directory doesn't exist. 186 if (base::win::GetVersion() >= base::win::VERSION_VISTA) 187 file_util::CreateDirectory(to_path); 188 else 189 ShellCopy(from_path, to_path, false); 190 } 191 192 FilePath directory = from_path.Append(L"*.*"); 193 return ShellCopy(directory, to_path, false); 194 } 195 196 bool PathExists(const FilePath& path) { 197 ThreadRestrictions::AssertIOAllowed(); 198 return (GetFileAttributes(path.value().c_str()) != INVALID_FILE_ATTRIBUTES); 199 } 200 201 bool PathIsWritable(const FilePath& path) { 202 ThreadRestrictions::AssertIOAllowed(); 203 HANDLE dir = 204 CreateFile(path.value().c_str(), FILE_ADD_FILE, kFileShareAll, 205 NULL, OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL); 206 207 if (dir == INVALID_HANDLE_VALUE) 208 return false; 209 210 CloseHandle(dir); 211 return true; 212 } 213 214 bool DirectoryExists(const FilePath& path) { 215 ThreadRestrictions::AssertIOAllowed(); 216 DWORD fileattr = GetFileAttributes(path.value().c_str()); 217 if (fileattr != INVALID_FILE_ATTRIBUTES) 218 return (fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0; 219 return false; 220 } 221 222 } // namespace base 223 224 // ----------------------------------------------------------------------------- 225 226 namespace file_util { 227 228 using base::DirectoryExists; 229 using base::FilePath; 230 using base::kFileShareAll; 231 232 bool GetTempDir(FilePath* path) { 233 base::ThreadRestrictions::AssertIOAllowed(); 234 235 wchar_t temp_path[MAX_PATH + 1]; 236 DWORD path_len = ::GetTempPath(MAX_PATH, temp_path); 237 if (path_len >= MAX_PATH || path_len <= 0) 238 return false; 239 // TODO(evanm): the old behavior of this function was to always strip the 240 // trailing slash. We duplicate this here, but it shouldn't be necessary 241 // when everyone is using the appropriate FilePath APIs. 242 *path = FilePath(temp_path).StripTrailingSeparators(); 243 return true; 244 } 245 246 bool GetShmemTempDir(FilePath* path, bool executable) { 247 return GetTempDir(path); 248 } 249 250 bool CreateTemporaryFile(FilePath* path) { 251 base::ThreadRestrictions::AssertIOAllowed(); 252 253 FilePath temp_file; 254 255 if (!GetTempDir(path)) 256 return false; 257 258 if (CreateTemporaryFileInDir(*path, &temp_file)) { 259 *path = temp_file; 260 return true; 261 } 262 263 return false; 264 } 265 266 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) { 267 base::ThreadRestrictions::AssertIOAllowed(); 268 return CreateAndOpenTemporaryFile(path); 269 } 270 271 // On POSIX we have semantics to create and open a temporary file 272 // atomically. 273 // TODO(jrg): is there equivalent call to use on Windows instead of 274 // going 2-step? 275 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) { 276 base::ThreadRestrictions::AssertIOAllowed(); 277 if (!CreateTemporaryFileInDir(dir, path)) { 278 return NULL; 279 } 280 // Open file in binary mode, to avoid problems with fwrite. On Windows 281 // it replaces \n's with \r\n's, which may surprise you. 282 // Reference: http://msdn.microsoft.com/en-us/library/h9t88zwz(VS.71).aspx 283 return OpenFile(*path, "wb+"); 284 } 285 286 bool CreateTemporaryFileInDir(const FilePath& dir, 287 FilePath* temp_file) { 288 base::ThreadRestrictions::AssertIOAllowed(); 289 290 wchar_t temp_name[MAX_PATH + 1]; 291 292 if (!GetTempFileName(dir.value().c_str(), L"", 0, temp_name)) { 293 DPLOG(WARNING) << "Failed to get temporary file name in " << dir.value(); 294 return false; 295 } 296 297 wchar_t long_temp_name[MAX_PATH + 1]; 298 DWORD long_name_len = GetLongPathName(temp_name, long_temp_name, MAX_PATH); 299 if (long_name_len > MAX_PATH || long_name_len == 0) { 300 // GetLongPathName() failed, but we still have a temporary file. 301 *temp_file = FilePath(temp_name); 302 return true; 303 } 304 305 FilePath::StringType long_temp_name_str; 306 long_temp_name_str.assign(long_temp_name, long_name_len); 307 *temp_file = FilePath(long_temp_name_str); 308 return true; 309 } 310 311 bool CreateTemporaryDirInDir(const FilePath& base_dir, 312 const FilePath::StringType& prefix, 313 FilePath* new_dir) { 314 base::ThreadRestrictions::AssertIOAllowed(); 315 316 FilePath path_to_create; 317 318 for (int count = 0; count < 50; ++count) { 319 // Try create a new temporary directory with random generated name. If 320 // the one exists, keep trying another path name until we reach some limit. 321 string16 new_dir_name; 322 new_dir_name.assign(prefix); 323 new_dir_name.append(base::IntToString16(::base::GetCurrentProcId())); 324 new_dir_name.push_back('_'); 325 new_dir_name.append(base::IntToString16(base::RandInt(0, kint16max))); 326 327 path_to_create = base_dir.Append(new_dir_name); 328 if (::CreateDirectory(path_to_create.value().c_str(), NULL)) { 329 *new_dir = path_to_create; 330 return true; 331 } 332 } 333 334 return false; 335 } 336 337 bool CreateNewTempDirectory(const FilePath::StringType& prefix, 338 FilePath* new_temp_path) { 339 base::ThreadRestrictions::AssertIOAllowed(); 340 341 FilePath system_temp_dir; 342 if (!GetTempDir(&system_temp_dir)) 343 return false; 344 345 return CreateTemporaryDirInDir(system_temp_dir, prefix, new_temp_path); 346 } 347 348 bool CreateDirectoryAndGetError(const FilePath& full_path, 349 base::PlatformFileError* error) { 350 base::ThreadRestrictions::AssertIOAllowed(); 351 352 // If the path exists, we've succeeded if it's a directory, failed otherwise. 353 const wchar_t* full_path_str = full_path.value().c_str(); 354 DWORD fileattr = ::GetFileAttributes(full_path_str); 355 if (fileattr != INVALID_FILE_ATTRIBUTES) { 356 if ((fileattr & FILE_ATTRIBUTE_DIRECTORY) != 0) { 357 DVLOG(1) << "CreateDirectory(" << full_path_str << "), " 358 << "directory already exists."; 359 return true; 360 } 361 DLOG(WARNING) << "CreateDirectory(" << full_path_str << "), " 362 << "conflicts with existing file."; 363 if (error) { 364 *error = base::PLATFORM_FILE_ERROR_NOT_A_DIRECTORY; 365 } 366 return false; 367 } 368 369 // Invariant: Path does not exist as file or directory. 370 371 // Attempt to create the parent recursively. This will immediately return 372 // true if it already exists, otherwise will create all required parent 373 // directories starting with the highest-level missing parent. 374 FilePath parent_path(full_path.DirName()); 375 if (parent_path.value() == full_path.value()) { 376 if (error) { 377 *error = base::PLATFORM_FILE_ERROR_NOT_FOUND; 378 } 379 return false; 380 } 381 if (!CreateDirectoryAndGetError(parent_path, error)) { 382 DLOG(WARNING) << "Failed to create one of the parent directories."; 383 if (error) { 384 DCHECK(*error != base::PLATFORM_FILE_OK); 385 } 386 return false; 387 } 388 389 if (!::CreateDirectory(full_path_str, NULL)) { 390 DWORD error_code = ::GetLastError(); 391 if (error_code == ERROR_ALREADY_EXISTS && DirectoryExists(full_path)) { 392 // This error code ERROR_ALREADY_EXISTS doesn't indicate whether we 393 // were racing with someone creating the same directory, or a file 394 // with the same path. If DirectoryExists() returns true, we lost the 395 // race to create the same directory. 396 return true; 397 } else { 398 if (error) 399 *error = base::LastErrorToPlatformFileError(error_code); 400 DLOG(WARNING) << "Failed to create directory " << full_path_str 401 << ", last error is " << error_code << "."; 402 return false; 403 } 404 } else { 405 return true; 406 } 407 } 408 409 // TODO(rkc): Work out if we want to handle NTFS junctions here or not, handle 410 // them if we do decide to. 411 bool IsLink(const FilePath& file_path) { 412 return false; 413 } 414 415 bool GetFileInfo(const FilePath& file_path, base::PlatformFileInfo* results) { 416 base::ThreadRestrictions::AssertIOAllowed(); 417 418 WIN32_FILE_ATTRIBUTE_DATA attr; 419 if (!GetFileAttributesEx(file_path.value().c_str(), 420 GetFileExInfoStandard, &attr)) { 421 return false; 422 } 423 424 ULARGE_INTEGER size; 425 size.HighPart = attr.nFileSizeHigh; 426 size.LowPart = attr.nFileSizeLow; 427 results->size = size.QuadPart; 428 429 results->is_directory = 430 (attr.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY) != 0; 431 results->last_modified = base::Time::FromFileTime(attr.ftLastWriteTime); 432 results->last_accessed = base::Time::FromFileTime(attr.ftLastAccessTime); 433 results->creation_time = base::Time::FromFileTime(attr.ftCreationTime); 434 435 return true; 436 } 437 438 FILE* OpenFile(const FilePath& filename, const char* mode) { 439 base::ThreadRestrictions::AssertIOAllowed(); 440 std::wstring w_mode = ASCIIToWide(std::string(mode)); 441 return _wfsopen(filename.value().c_str(), w_mode.c_str(), _SH_DENYNO); 442 } 443 444 FILE* OpenFile(const std::string& filename, const char* mode) { 445 base::ThreadRestrictions::AssertIOAllowed(); 446 return _fsopen(filename.c_str(), mode, _SH_DENYNO); 447 } 448 449 int ReadFile(const FilePath& filename, char* data, int size) { 450 base::ThreadRestrictions::AssertIOAllowed(); 451 base::win::ScopedHandle file(CreateFile(filename.value().c_str(), 452 GENERIC_READ, 453 FILE_SHARE_READ | FILE_SHARE_WRITE, 454 NULL, 455 OPEN_EXISTING, 456 FILE_FLAG_SEQUENTIAL_SCAN, 457 NULL)); 458 if (!file) 459 return -1; 460 461 DWORD read; 462 if (::ReadFile(file, data, size, &read, NULL) && 463 static_cast<int>(read) == size) 464 return read; 465 return -1; 466 } 467 468 int WriteFile(const FilePath& filename, const char* data, int size) { 469 base::ThreadRestrictions::AssertIOAllowed(); 470 base::win::ScopedHandle file(CreateFile(filename.value().c_str(), 471 GENERIC_WRITE, 472 0, 473 NULL, 474 CREATE_ALWAYS, 475 0, 476 NULL)); 477 if (!file) { 478 DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path " 479 << filename.value(); 480 return -1; 481 } 482 483 DWORD written; 484 BOOL result = ::WriteFile(file, data, size, &written, NULL); 485 if (result && static_cast<int>(written) == size) 486 return written; 487 488 if (!result) { 489 // WriteFile failed. 490 DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value() 491 << " failed"; 492 } else { 493 // Didn't write all the bytes. 494 DLOG(WARNING) << "wrote" << written << " bytes to " 495 << filename.value() << " expected " << size; 496 } 497 return -1; 498 } 499 500 int AppendToFile(const FilePath& filename, const char* data, int size) { 501 base::ThreadRestrictions::AssertIOAllowed(); 502 base::win::ScopedHandle file(CreateFile(filename.value().c_str(), 503 FILE_APPEND_DATA, 504 0, 505 NULL, 506 OPEN_EXISTING, 507 0, 508 NULL)); 509 if (!file) { 510 DLOG_GETLASTERROR(WARNING) << "CreateFile failed for path " 511 << filename.value(); 512 return -1; 513 } 514 515 DWORD written; 516 BOOL result = ::WriteFile(file, data, size, &written, NULL); 517 if (result && static_cast<int>(written) == size) 518 return written; 519 520 if (!result) { 521 // WriteFile failed. 522 DLOG_GETLASTERROR(WARNING) << "writing file " << filename.value() 523 << " failed"; 524 } else { 525 // Didn't write all the bytes. 526 DLOG(WARNING) << "wrote" << written << " bytes to " 527 << filename.value() << " expected " << size; 528 } 529 return -1; 530 } 531 532 // Gets the current working directory for the process. 533 bool GetCurrentDirectory(FilePath* dir) { 534 base::ThreadRestrictions::AssertIOAllowed(); 535 536 wchar_t system_buffer[MAX_PATH]; 537 system_buffer[0] = 0; 538 DWORD len = ::GetCurrentDirectory(MAX_PATH, system_buffer); 539 if (len == 0 || len > MAX_PATH) 540 return false; 541 // TODO(evanm): the old behavior of this function was to always strip the 542 // trailing slash. We duplicate this here, but it shouldn't be necessary 543 // when everyone is using the appropriate FilePath APIs. 544 std::wstring dir_str(system_buffer); 545 *dir = FilePath(dir_str).StripTrailingSeparators(); 546 return true; 547 } 548 549 // Sets the current working directory for the process. 550 bool SetCurrentDirectory(const FilePath& directory) { 551 base::ThreadRestrictions::AssertIOAllowed(); 552 BOOL ret = ::SetCurrentDirectory(directory.value().c_str()); 553 return ret != 0; 554 } 555 556 bool NormalizeFilePath(const FilePath& path, FilePath* real_path) { 557 base::ThreadRestrictions::AssertIOAllowed(); 558 FilePath mapped_file; 559 if (!NormalizeToNativeFilePath(path, &mapped_file)) 560 return false; 561 // NormalizeToNativeFilePath() will return a path that starts with 562 // "\Device\Harddisk...". Helper DevicePathToDriveLetterPath() 563 // will find a drive letter which maps to the path's device, so 564 // that we return a path starting with a drive letter. 565 return DevicePathToDriveLetterPath(mapped_file, real_path); 566 } 567 568 bool DevicePathToDriveLetterPath(const FilePath& nt_device_path, 569 FilePath* out_drive_letter_path) { 570 base::ThreadRestrictions::AssertIOAllowed(); 571 572 // Get the mapping of drive letters to device paths. 573 const int kDriveMappingSize = 1024; 574 wchar_t drive_mapping[kDriveMappingSize] = {'\0'}; 575 if (!::GetLogicalDriveStrings(kDriveMappingSize - 1, drive_mapping)) { 576 DLOG(ERROR) << "Failed to get drive mapping."; 577 return false; 578 } 579 580 // The drive mapping is a sequence of null terminated strings. 581 // The last string is empty. 582 wchar_t* drive_map_ptr = drive_mapping; 583 wchar_t device_path_as_string[MAX_PATH]; 584 wchar_t drive[] = L" :"; 585 586 // For each string in the drive mapping, get the junction that links 587 // to it. If that junction is a prefix of |device_path|, then we 588 // know that |drive| is the real path prefix. 589 while (*drive_map_ptr) { 590 drive[0] = drive_map_ptr[0]; // Copy the drive letter. 591 592 if (QueryDosDevice(drive, device_path_as_string, MAX_PATH)) { 593 FilePath device_path(device_path_as_string); 594 if (device_path == nt_device_path || 595 device_path.IsParent(nt_device_path)) { 596 *out_drive_letter_path = FilePath(drive + 597 nt_device_path.value().substr(wcslen(device_path_as_string))); 598 return true; 599 } 600 } 601 // Move to the next drive letter string, which starts one 602 // increment after the '\0' that terminates the current string. 603 while (*drive_map_ptr++); 604 } 605 606 // No drive matched. The path does not start with a device junction 607 // that is mounted as a drive letter. This means there is no drive 608 // letter path to the volume that holds |device_path|, so fail. 609 return false; 610 } 611 612 bool NormalizeToNativeFilePath(const FilePath& path, FilePath* nt_path) { 613 base::ThreadRestrictions::AssertIOAllowed(); 614 // In Vista, GetFinalPathNameByHandle() would give us the real path 615 // from a file handle. If we ever deprecate XP, consider changing the 616 // code below to a call to GetFinalPathNameByHandle(). The method this 617 // function uses is explained in the following msdn article: 618 // http://msdn.microsoft.com/en-us/library/aa366789(VS.85).aspx 619 base::win::ScopedHandle file_handle( 620 ::CreateFile(path.value().c_str(), 621 GENERIC_READ, 622 kFileShareAll, 623 NULL, 624 OPEN_EXISTING, 625 FILE_ATTRIBUTE_NORMAL, 626 NULL)); 627 if (!file_handle) 628 return false; 629 630 // Create a file mapping object. Can't easily use MemoryMappedFile, because 631 // we only map the first byte, and need direct access to the handle. You can 632 // not map an empty file, this call fails in that case. 633 base::win::ScopedHandle file_map_handle( 634 ::CreateFileMapping(file_handle.Get(), 635 NULL, 636 PAGE_READONLY, 637 0, 638 1, // Just one byte. No need to look at the data. 639 NULL)); 640 if (!file_map_handle) 641 return false; 642 643 // Use a view of the file to get the path to the file. 644 void* file_view = MapViewOfFile(file_map_handle.Get(), 645 FILE_MAP_READ, 0, 0, 1); 646 if (!file_view) 647 return false; 648 649 // The expansion of |path| into a full path may make it longer. 650 // GetMappedFileName() will fail if the result is longer than MAX_PATH. 651 // Pad a bit to be safe. If kMaxPathLength is ever changed to be less 652 // than MAX_PATH, it would be nessisary to test that GetMappedFileName() 653 // not return kMaxPathLength. This would mean that only part of the 654 // path fit in |mapped_file_path|. 655 const int kMaxPathLength = MAX_PATH + 10; 656 wchar_t mapped_file_path[kMaxPathLength]; 657 bool success = false; 658 HANDLE cp = GetCurrentProcess(); 659 if (::GetMappedFileNameW(cp, file_view, mapped_file_path, kMaxPathLength)) { 660 *nt_path = FilePath(mapped_file_path); 661 success = true; 662 } 663 ::UnmapViewOfFile(file_view); 664 return success; 665 } 666 667 int GetMaximumPathComponentLength(const FilePath& path) { 668 base::ThreadRestrictions::AssertIOAllowed(); 669 670 wchar_t volume_path[MAX_PATH]; 671 if (!GetVolumePathNameW(path.NormalizePathSeparators().value().c_str(), 672 volume_path, 673 arraysize(volume_path))) { 674 return -1; 675 } 676 677 DWORD max_length = 0; 678 if (!GetVolumeInformationW(volume_path, NULL, 0, NULL, &max_length, NULL, 679 NULL, 0)) { 680 return -1; 681 } 682 683 // Length of |path| with path separator appended. 684 size_t prefix = path.StripTrailingSeparators().value().size() + 1; 685 // The whole path string must be shorter than MAX_PATH. That is, it must be 686 // prefix + component_length < MAX_PATH (or equivalently, <= MAX_PATH - 1). 687 int whole_path_limit = std::max(0, MAX_PATH - 1 - static_cast<int>(prefix)); 688 return std::min(whole_path_limit, static_cast<int>(max_length)); 689 } 690 691 } // namespace file_util 692 693 namespace base { 694 namespace internal { 695 696 bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) { 697 ThreadRestrictions::AssertIOAllowed(); 698 699 // NOTE: I suspect we could support longer paths, but that would involve 700 // analyzing all our usage of files. 701 if (from_path.value().length() >= MAX_PATH || 702 to_path.value().length() >= MAX_PATH) { 703 return false; 704 } 705 if (MoveFileEx(from_path.value().c_str(), to_path.value().c_str(), 706 MOVEFILE_COPY_ALLOWED | MOVEFILE_REPLACE_EXISTING) != 0) 707 return true; 708 709 // Keep the last error value from MoveFileEx around in case the below 710 // fails. 711 bool ret = false; 712 DWORD last_error = ::GetLastError(); 713 714 if (DirectoryExists(from_path)) { 715 // MoveFileEx fails if moving directory across volumes. We will simulate 716 // the move by using Copy and Delete. Ideally we could check whether 717 // from_path and to_path are indeed in different volumes. 718 ret = internal::CopyAndDeleteDirectory(from_path, to_path); 719 } 720 721 if (!ret) { 722 // Leave a clue about what went wrong so that it can be (at least) picked 723 // up by a PLOG entry. 724 ::SetLastError(last_error); 725 } 726 727 return ret; 728 } 729 730 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) { 731 ThreadRestrictions::AssertIOAllowed(); 732 733 // NOTE: I suspect we could support longer paths, but that would involve 734 // analyzing all our usage of files. 735 if (from_path.value().length() >= MAX_PATH || 736 to_path.value().length() >= MAX_PATH) { 737 return false; 738 } 739 return (::CopyFile(from_path.value().c_str(), to_path.value().c_str(), 740 false) != 0); 741 } 742 743 bool CopyAndDeleteDirectory(const FilePath& from_path, 744 const FilePath& to_path) { 745 ThreadRestrictions::AssertIOAllowed(); 746 if (CopyDirectory(from_path, to_path, true)) { 747 if (DeleteFile(from_path, true)) 748 return true; 749 750 // Like Move, this function is not transactional, so we just 751 // leave the copied bits behind if deleting from_path fails. 752 // If to_path exists previously then we have already overwritten 753 // it by now, we don't get better off by deleting the new bits. 754 } 755 return false; 756 } 757 758 } // namespace internal 759 } // namespace base 760
