base/file_util_posix.cc

   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 <dirent.h>
   8 #include <errno.h>
   9 #include <fcntl.h>
  10 #include <libgen.h>
  11 #include <limits.h>
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <sys/errno.h>
  16 #include <sys/mman.h>
  17 #include <sys/param.h>
  18 #include <sys/stat.h>
  19 #include <sys/time.h>
  20 #include <sys/types.h>
  21 #include <time.h>
  22 #include <unistd.h>
  23
  24 #if defined(OS_MACOSX)
  25 #include <AvailabilityMacros.h>
  26 #include "base/mac/foundation_util.h"
  27 #elif !defined(OS_CHROMEOS) && defined(USE_GLIB)
  28 #include <glib.h>  // for g_get_home_dir()
  29 #endif
  30
  31 #include <fstream>
  32
  33 #include "base/basictypes.h"
  34 #include "base/files/file_enumerator.h"
  35 #include "base/files/file_path.h"
  36 #include "base/logging.h"
  37 #include "base/memory/scoped_ptr.h"
  38 #include "base/memory/singleton.h"
  39 #include "base/path_service.h"
  40 #include "base/posix/eintr_wrapper.h"
  41 #include "base/stl_util.h"
  42 #include "base/strings/string_util.h"
  43 #include "base/strings/stringprintf.h"
  44 #include "base/strings/sys_string_conversions.h"
  45 #include "base/strings/utf_string_conversions.h"
  46 #include "base/sys_info.h"
  47 #include "base/threading/thread_restrictions.h"
  48 #include "base/time/time.h"
  49
  50 #if defined(OS_ANDROID)
  51 #include "base/android/content_uri_utils.h"
  52 #include "base/os_compat_android.h"
  53 #endif
  54
  55 #if !defined(OS_IOS)
  56 #include <grp.h>
  57 #endif
  58
  59 namespace base {
  60
  61 namespace {
  62
  63 #if defined(OS_BSD) || defined(OS_MACOSX)
  64 typedef struct stat stat_wrapper_t;
  65 static int CallStat(const char *path, stat_wrapper_t *sb) {
  66   ThreadRestrictions::AssertIOAllowed();
  67   return stat(path, sb);
  68 }
  69 static int CallLstat(const char *path, stat_wrapper_t *sb) {
  70   ThreadRestrictions::AssertIOAllowed();
  71   return lstat(path, sb);
  72 }
  73 #else
  74 typedef struct stat64 stat_wrapper_t;
  75 static int CallStat(const char *path, stat_wrapper_t *sb) {
  76   ThreadRestrictions::AssertIOAllowed();
  77   return stat64(path, sb);
  78 }
  79 static int CallLstat(const char *path, stat_wrapper_t *sb) {
  80   ThreadRestrictions::AssertIOAllowed();
  81   return lstat64(path, sb);
  82 }
  83 #if defined(OS_ANDROID)
  84 static int CallFstat(int fd, stat_wrapper_t *sb) {
  85   ThreadRestrictions::AssertIOAllowed();
  86   return fstat64(fd, sb);
  87 }
  88 #endif
  89 #endif
  90
  91 // Helper for NormalizeFilePath(), defined below.
  92 bool RealPath(const FilePath& path, FilePath* real_path) {
  93   ThreadRestrictions::AssertIOAllowed();  // For realpath().
  94   FilePath::CharType buf[PATH_MAX];
  95   if (!realpath(path.value().c_str(), buf))
  96     return false;
  97
  98   *real_path = FilePath(buf);
  99   return true;
 100 }
 101
 102 // Helper for VerifyPathControlledByUser.
 103 bool VerifySpecificPathControlledByUser(const FilePath& path,
 104                                         uid_t owner_uid,
 105                                         const std::set<gid_t>& group_gids) {
 106   stat_wrapper_t stat_info;
 107   if (CallLstat(path.value().c_str(), &stat_info) != 0) {
 108     DPLOG(ERROR) << "Failed to get information on path "
 109                  << path.value();
 110     return false;
 111   }
 112
 113   if (S_ISLNK(stat_info.st_mode)) {
 114     DLOG(ERROR) << "Path " << path.value()
 115                << " is a symbolic link.";
 116     return false;
 117   }
 118
 119   if (stat_info.st_uid != owner_uid) {
 120     DLOG(ERROR) << "Path " << path.value()
 121                 << " is owned by the wrong user.";
 122     return false;
 123   }
 124
 125   if ((stat_info.st_mode & S_IWGRP) &&
 126       !ContainsKey(group_gids, stat_info.st_gid)) {
 127     DLOG(ERROR) << "Path " << path.value()
 128                 << " is writable by an unprivileged group.";
 129     return false;
 130   }
 131
 132   if (stat_info.st_mode & S_IWOTH) {
 133     DLOG(ERROR) << "Path " << path.value()
 134                 << " is writable by any user.";
 135     return false;
 136   }
 137
 138   return true;
 139 }
 140
 141 std::string TempFileName() {
 142 #if defined(OS_MACOSX)
 143   return StringPrintf(".%s.XXXXXX", base::mac::BaseBundleID());
 144 #endif
 145
 146 #if defined(GOOGLE_CHROME_BUILD)
 147   return std::string(".com.google.Chrome.XXXXXX");
 148 #else
 149   return std::string(".org.chromium.Chromium.XXXXXX");
 150 #endif
 151 }
 152
 153 // Creates and opens a temporary file in |directory|, returning the
 154 // file descriptor. |path| is set to the temporary file path.
 155 // This function does NOT unlink() the file.
 156 int CreateAndOpenFdForTemporaryFile(FilePath directory, FilePath* path) {
 157   ThreadRestrictions::AssertIOAllowed();  // For call to mkstemp().
 158   *path = directory.Append(base::TempFileName());
 159   const std::string& tmpdir_string = path->value();
 160   // this should be OK since mkstemp just replaces characters in place
 161   char* buffer = const_cast<char*>(tmpdir_string.c_str());
 162
 163   return HANDLE_EINTR(mkstemp(buffer));
 164 }
 165
 166 #if defined(OS_LINUX)
 167 // Determine if /dev/shm files can be mapped and then mprotect'd PROT_EXEC.
 168 // This depends on the mount options used for /dev/shm, which vary among
 169 // different Linux distributions and possibly local configuration.  It also
 170 // depends on details of kernel--ChromeOS uses the noexec option for /dev/shm
 171 // but its kernel allows mprotect with PROT_EXEC anyway.
 172 bool DetermineDevShmExecutable() {
 173   bool result = false;
 174   FilePath path;
 175   int fd = CreateAndOpenFdForTemporaryFile(FilePath("/dev/shm"), &path);
 176   if (fd >= 0) {
 177     file_util::ScopedFD shm_fd_closer(&fd);
 178     DeleteFile(path, false);
 179     long sysconf_result = sysconf(_SC_PAGESIZE);
 180     CHECK_GE(sysconf_result, 0);
 181     size_t pagesize = static_cast<size_t>(sysconf_result);
 182     CHECK_GE(sizeof(pagesize), sizeof(sysconf_result));
 183     void *mapping = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, fd, 0);
 184     if (mapping != MAP_FAILED) {
 185       if (mprotect(mapping, pagesize, PROT_READ | PROT_EXEC) == 0)
 186         result = true;
 187       munmap(mapping, pagesize);
 188     }
 189   }
 190   return result;
 191 }
 192 #endif  // defined(OS_LINUX)
 193
 194 }  // namespace
 195
 196 FilePath MakeAbsoluteFilePath(const FilePath& input) {
 197   ThreadRestrictions::AssertIOAllowed();
 198   char full_path[PATH_MAX];
 199   if (realpath(input.value().c_str(), full_path) == NULL)
 200     return FilePath();
 201   return FilePath(full_path);
 202 }
 203
 204 // TODO(erikkay): The Windows version of this accepts paths like "foo/bar/*"
 205 // which works both with and without the recursive flag.  I'm not sure we need
 206 // that functionality. If not, remove from file_util_win.cc, otherwise add it
 207 // here.
 208 bool DeleteFile(const FilePath& path, bool recursive) {
 209   ThreadRestrictions::AssertIOAllowed();
 210   const char* path_str = path.value().c_str();
 211   stat_wrapper_t file_info;
 212   int test = CallLstat(path_str, &file_info);
 213   if (test != 0) {
 214     // The Windows version defines this condition as success.
 215     bool ret = (errno == ENOENT || errno == ENOTDIR);
 216     return ret;
 217   }
 218   if (!S_ISDIR(file_info.st_mode))
 219     return (unlink(path_str) == 0);
 220   if (!recursive)
 221     return (rmdir(path_str) == 0);
 222
 223   bool success = true;
 224   std::stack<std::string> directories;
 225   directories.push(path.value());
 226   FileEnumerator traversal(path, true,
 227       FileEnumerator::FILES | FileEnumerator::DIRECTORIES |
 228       FileEnumerator::SHOW_SYM_LINKS);
 229   for (FilePath current = traversal.Next(); success && !current.empty();
 230        current = traversal.Next()) {
 231     if (traversal.GetInfo().IsDirectory())
 232       directories.push(current.value());
 233     else
 234       success = (unlink(current.value().c_str()) == 0);
 235   }
 236
 237   while (success && !directories.empty()) {
 238     FilePath dir = FilePath(directories.top());
 239     directories.pop();
 240     success = (rmdir(dir.value().c_str()) == 0);
 241   }
 242   return success;
 243 }
 244
 245 bool ReplaceFile(const FilePath& from_path,
 246                  const FilePath& to_path,
 247                  File::Error* error) {
 248   ThreadRestrictions::AssertIOAllowed();
 249   if (rename(from_path.value().c_str(), to_path.value().c_str()) == 0)
 250     return true;
 251   if (error)
 252     *error = File::OSErrorToFileError(errno);
 253   return false;
 254 }
 255
 256 bool CopyDirectory(const FilePath& from_path,
 257                    const FilePath& to_path,
 258                    bool recursive) {
 259   ThreadRestrictions::AssertIOAllowed();
 260   // Some old callers of CopyDirectory want it to support wildcards.
 261   // After some discussion, we decided to fix those callers.
 262   // Break loudly here if anyone tries to do this.
 263   // TODO(evanm): remove this once we're sure it's ok.
 264   DCHECK(to_path.value().find('*') == std::string::npos);
 265   DCHECK(from_path.value().find('*') == std::string::npos);
 266
 267   char top_dir[PATH_MAX];
 268   if (strlcpy(top_dir, from_path.value().c_str(),
 269               arraysize(top_dir)) >= arraysize(top_dir)) {
 270     return false;
 271   }
 272
 273   // This function does not properly handle destinations within the source
 274   FilePath real_to_path = to_path;
 275   if (PathExists(real_to_path)) {
 276     real_to_path = MakeAbsoluteFilePath(real_to_path);
 277     if (real_to_path.empty())
 278       return false;
 279   } else {
 280     real_to_path = MakeAbsoluteFilePath(real_to_path.DirName());
 281     if (real_to_path.empty())
 282       return false;
 283   }
 284   FilePath real_from_path = MakeAbsoluteFilePath(from_path);
 285   if (real_from_path.empty())
 286     return false;
 287   if (real_to_path.value().size() >= real_from_path.value().size() &&
 288       real_to_path.value().compare(0, real_from_path.value().size(),
 289       real_from_path.value()) == 0)
 290     return false;
 291
 292   bool success = true;
 293   int traverse_type = FileEnumerator::FILES | FileEnumerator::SHOW_SYM_LINKS;
 294   if (recursive)
 295     traverse_type |= FileEnumerator::DIRECTORIES;
 296   FileEnumerator traversal(from_path, recursive, traverse_type);
 297
 298   // We have to mimic windows behavior here. |to_path| may not exist yet,
 299   // start the loop with |to_path|.
 300   struct stat from_stat;
 301   FilePath current = from_path;
 302   if (stat(from_path.value().c_str(), &from_stat) < 0) {
 303     DLOG(ERROR) << "CopyDirectory() couldn't stat source directory: "
 304                 << from_path.value() << " errno = " << errno;
 305     success = false;
 306   }
 307   struct stat to_path_stat;
 308   FilePath from_path_base = from_path;
 309   if (recursive && stat(to_path.value().c_str(), &to_path_stat) == 0 &&
 310       S_ISDIR(to_path_stat.st_mode)) {
 311     // If the destination already exists and is a directory, then the
 312     // top level of source needs to be copied.
 313     from_path_base = from_path.DirName();
 314   }
 315
 316   // The Windows version of this function assumes that non-recursive calls
 317   // will always have a directory for from_path.
 318   DCHECK(recursive || S_ISDIR(from_stat.st_mode));
 319
 320   while (success && !current.empty()) {
 321     // current is the source path, including from_path, so append
 322     // the suffix after from_path to to_path to create the target_path.
 323     FilePath target_path(to_path);
 324     if (from_path_base != current) {
 325       if (!from_path_base.AppendRelativePath(current, &target_path)) {
 326         success = false;
 327         break;
 328       }
 329     }
 330
 331     if (S_ISDIR(from_stat.st_mode)) {
 332       if (mkdir(target_path.value().c_str(), from_stat.st_mode & 01777) != 0 &&
 333           errno != EEXIST) {
 334         DLOG(ERROR) << "CopyDirectory() couldn't create directory: "
 335                     << target_path.value() << " errno = " << errno;
 336         success = false;
 337       }
 338     } else if (S_ISREG(from_stat.st_mode)) {
 339       if (!CopyFile(current, target_path)) {
 340         DLOG(ERROR) << "CopyDirectory() couldn't create file: "
 341                     << target_path.value();
 342         success = false;
 343       }
 344     } else {
 345       DLOG(WARNING) << "CopyDirectory() skipping non-regular file: "
 346                     << current.value();
 347     }
 348
 349     current = traversal.Next();
 350     if (!current.empty())
 351       from_stat = traversal.GetInfo().stat();
 352   }
 353
 354   return success;
 355 }
 356
 357 bool PathExists(const FilePath& path) {
 358   ThreadRestrictions::AssertIOAllowed();
 359 #if defined(OS_ANDROID)
 360   if (path.IsContentUri()) {
 361     return ContentUriExists(path);
 362   }
 363 #endif
 364   return access(path.value().c_str(), F_OK) == 0;
 365 }
 366
 367 bool PathIsWritable(const FilePath& path) {
 368   ThreadRestrictions::AssertIOAllowed();
 369   return access(path.value().c_str(), W_OK) == 0;
 370 }
 371
 372 bool DirectoryExists(const FilePath& path) {
 373   ThreadRestrictions::AssertIOAllowed();
 374   stat_wrapper_t file_info;
 375   if (CallStat(path.value().c_str(), &file_info) == 0)
 376     return S_ISDIR(file_info.st_mode);
 377   return false;
 378 }
 379
 380 bool ReadFromFD(int fd, char* buffer, size_t bytes) {
 381   size_t total_read = 0;
 382   while (total_read < bytes) {
 383     ssize_t bytes_read =
 384         HANDLE_EINTR(read(fd, buffer + total_read, bytes - total_read));
 385     if (bytes_read <= 0)
 386       break;
 387     total_read += bytes_read;
 388   }
 389   return total_read == bytes;
 390 }
 391
 392 bool CreateSymbolicLink(const FilePath& target_path,
 393                         const FilePath& symlink_path) {
 394   DCHECK(!symlink_path.empty());
 395   DCHECK(!target_path.empty());
 396   return ::symlink(target_path.value().c_str(),
 397                    symlink_path.value().c_str()) != -1;
 398 }
 399
 400 bool ReadSymbolicLink(const FilePath& symlink_path, FilePath* target_path) {
 401   DCHECK(!symlink_path.empty());
 402   DCHECK(target_path);
 403   char buf[PATH_MAX];
 404   ssize_t count = ::readlink(symlink_path.value().c_str(), buf, arraysize(buf));
 405
 406   if (count <= 0) {
 407     target_path->clear();
 408     return false;
 409   }
 410
 411   *target_path = FilePath(FilePath::StringType(buf, count));
 412   return true;
 413 }
 414
 415 bool GetPosixFilePermissions(const FilePath& path, int* mode) {
 416   ThreadRestrictions::AssertIOAllowed();
 417   DCHECK(mode);
 418
 419   stat_wrapper_t file_info;
 420   // Uses stat(), because on symbolic link, lstat() does not return valid
 421   // permission bits in st_mode
 422   if (CallStat(path.value().c_str(), &file_info) != 0)
 423     return false;
 424
 425   *mode = file_info.st_mode & FILE_PERMISSION_MASK;
 426   return true;
 427 }
 428
 429 bool SetPosixFilePermissions(const FilePath& path,
 430                              int mode) {
 431   ThreadRestrictions::AssertIOAllowed();
 432   DCHECK((mode & ~FILE_PERMISSION_MASK) == 0);
 433
 434   // Calls stat() so that we can preserve the higher bits like S_ISGID.
 435   stat_wrapper_t stat_buf;
 436   if (CallStat(path.value().c_str(), &stat_buf) != 0)
 437     return false;
 438
 439   // Clears the existing permission bits, and adds the new ones.
 440   mode_t updated_mode_bits = stat_buf.st_mode & ~FILE_PERMISSION_MASK;
 441   updated_mode_bits |= mode & FILE_PERMISSION_MASK;
 442
 443   if (HANDLE_EINTR(chmod(path.value().c_str(), updated_mode_bits)) != 0)
 444     return false;
 445
 446   return true;
 447 }
 448
 449 #if !defined(OS_MACOSX)
 450 // This is implemented in file_util_mac.mm for Mac.
 451 bool GetTempDir(FilePath* path) {
 452   const char* tmp = getenv("TMPDIR");
 453   if (tmp) {
 454     *path = FilePath(tmp);
 455   } else {
 456 #if defined(OS_ANDROID)
 457     return PathService::Get(base::DIR_CACHE, path);
 458 #else
 459     *path = FilePath("/tmp");
 460 #endif
 461   }
 462   return true;
 463 }
 464 #endif  // !defined(OS_MACOSX)
 465
 466 #if !defined(OS_MACOSX) && !defined(OS_ANDROID)
 467 // This is implemented in file_util_mac.mm and file_util_android.cc for those
 468 // platforms.
 469 bool GetShmemTempDir(bool executable, FilePath* path) {
 470 #if defined(OS_LINUX)
 471   bool use_dev_shm = true;
 472   if (executable) {
 473     static const bool s_dev_shm_executable = DetermineDevShmExecutable();
 474     use_dev_shm = s_dev_shm_executable;
 475   }
 476   if (use_dev_shm) {
 477     *path = FilePath("/dev/shm");
 478     return true;
 479   }
 480 #endif
 481   return GetTempDir(path);
 482 }
 483 #endif  // !defined(OS_MACOSX) && !defined(OS_ANDROID)
 484
 485 #if !defined(OS_MACOSX)
 486 FilePath GetHomeDir() {
 487 #if defined(OS_CHROMEOS)
 488   if (SysInfo::IsRunningOnChromeOS())
 489     return FilePath("/home/chronos/user");
 490 #endif
 491
 492   const char* home_dir = getenv("HOME");
 493   if (home_dir && home_dir[0])
 494     return FilePath(home_dir);
 495
 496 #if defined(OS_ANDROID)
 497   DLOG(WARNING) << "OS_ANDROID: Home directory lookup not yet implemented.";
 498 #elif defined(USE_GLIB) && !defined(OS_CHROMEOS)
 499   // g_get_home_dir calls getpwent, which can fall through to LDAP calls.
 500   ThreadRestrictions::AssertIOAllowed();
 501
 502   home_dir = g_get_home_dir();
 503   if (home_dir && home_dir[0])
 504     return FilePath(home_dir);
 505 #endif
 506
 507   FilePath rv;
 508   if (GetTempDir(&rv))
 509     return rv;
 510
 511   // Last resort.
 512   return FilePath("/tmp");
 513 }
 514 #endif  // !defined(OS_MACOSX)
 515
 516 bool CreateTemporaryFile(FilePath* path) {
 517   ThreadRestrictions::AssertIOAllowed();  // For call to close().
 518   FilePath directory;
 519   if (!GetTempDir(&directory))
 520     return false;
 521   int fd = CreateAndOpenFdForTemporaryFile(directory, path);
 522   if (fd < 0)
 523     return false;
 524   close(fd);
 525   return true;
 526 }
 527
 528 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
 529   FilePath directory;
 530   if (!GetShmemTempDir(executable, &directory))
 531     return NULL;
 532
 533   return CreateAndOpenTemporaryFileInDir(directory, path);
 534 }
 535
 536 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
 537   int fd = CreateAndOpenFdForTemporaryFile(dir, path);
 538   if (fd < 0)
 539     return NULL;
 540
 541   FILE* file = fdopen(fd, "a+");
 542   if (!file)
 543     close(fd);
 544   return file;
 545 }
 546
 547 bool CreateTemporaryFileInDir(const FilePath& dir, FilePath* temp_file) {
 548   ThreadRestrictions::AssertIOAllowed();  // For call to close().
 549   int fd = CreateAndOpenFdForTemporaryFile(dir, temp_file);
 550   return ((fd >= 0) && !IGNORE_EINTR(close(fd)));
 551 }
 552
 553 static bool CreateTemporaryDirInDirImpl(const FilePath& base_dir,
 554                                         const FilePath::StringType& name_tmpl,
 555                                         FilePath* new_dir) {
 556   ThreadRestrictions::AssertIOAllowed();  // For call to mkdtemp().
 557   DCHECK(name_tmpl.find("XXXXXX") != FilePath::StringType::npos)
 558       << "Directory name template must contain \"XXXXXX\".";
 559
 560   FilePath sub_dir = base_dir.Append(name_tmpl);
 561   std::string sub_dir_string = sub_dir.value();
 562
 563   // this should be OK since mkdtemp just replaces characters in place
 564   char* buffer = const_cast<char*>(sub_dir_string.c_str());
 565   char* dtemp = mkdtemp(buffer);
 566   if (!dtemp) {
 567     DPLOG(ERROR) << "mkdtemp";
 568     return false;
 569   }
 570   *new_dir = FilePath(dtemp);
 571   return true;
 572 }
 573
 574 bool CreateTemporaryDirInDir(const FilePath& base_dir,
 575                              const FilePath::StringType& prefix,
 576                              FilePath* new_dir) {
 577   FilePath::StringType mkdtemp_template = prefix;
 578   mkdtemp_template.append(FILE_PATH_LITERAL("XXXXXX"));
 579   return CreateTemporaryDirInDirImpl(base_dir, mkdtemp_template, new_dir);
 580 }
 581
 582 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 583                             FilePath* new_temp_path) {
 584   FilePath tmpdir;
 585   if (!GetTempDir(&tmpdir))
 586     return false;
 587
 588   return CreateTemporaryDirInDirImpl(tmpdir, TempFileName(), new_temp_path);
 589 }
 590
 591 bool CreateDirectoryAndGetError(const FilePath& full_path,
 592                                 File::Error* error) {
 593   ThreadRestrictions::AssertIOAllowed();  // For call to mkdir().
 594   std::vector<FilePath> subpaths;
 595
 596   // Collect a list of all parent directories.
 597   FilePath last_path = full_path;
 598   subpaths.push_back(full_path);
 599   for (FilePath path = full_path.DirName();
 600        path.value() != last_path.value(); path = path.DirName()) {
 601     subpaths.push_back(path);
 602     last_path = path;
 603   }
 604
 605   // Iterate through the parents and create the missing ones.
 606   for (std::vector<FilePath>::reverse_iterator i = subpaths.rbegin();
 607        i != subpaths.rend(); ++i) {
 608     if (DirectoryExists(*i))
 609       continue;
 610     if (mkdir(i->value().c_str(), 0700) == 0)
 611       continue;
 612     // Mkdir failed, but it might have failed with EEXIST, or some other error
 613     // due to the the directory appearing out of thin air. This can occur if
 614     // two processes are trying to create the same file system tree at the same
 615     // time. Check to see if it exists and make sure it is a directory.
 616     int saved_errno = errno;
 617     if (!DirectoryExists(*i)) {
 618       if (error)
 619         *error = File::OSErrorToFileError(saved_errno);
 620       return false;
 621     }
 622   }
 623   return true;
 624 }
 625
 626 bool NormalizeFilePath(const FilePath& path, FilePath* normalized_path) {
 627   FilePath real_path_result;
 628   if (!RealPath(path, &real_path_result))
 629     return false;
 630
 631   // To be consistant with windows, fail if |real_path_result| is a
 632   // directory.
 633   stat_wrapper_t file_info;
 634   if (CallStat(real_path_result.value().c_str(), &file_info) != 0 ||
 635       S_ISDIR(file_info.st_mode))
 636     return false;
 637
 638   *normalized_path = real_path_result;
 639   return true;
 640 }
 641
 642 // TODO(rkc): Refactor GetFileInfo and FileEnumerator to handle symlinks
 643 // correctly. http://code.google.com/p/chromium-os/issues/detail?id=15948
 644 bool IsLink(const FilePath& file_path) {
 645   stat_wrapper_t st;
 646   // If we can't lstat the file, it's safe to assume that the file won't at
 647   // least be a 'followable' link.
 648   if (CallLstat(file_path.value().c_str(), &st) != 0)
 649     return false;
 650
 651   if (S_ISLNK(st.st_mode))
 652     return true;
 653   else
 654     return false;
 655 }
 656
 657 bool GetFileInfo(const FilePath& file_path, File::Info* results) {
 658   stat_wrapper_t file_info;
 659 #if defined(OS_ANDROID)
 660   if (file_path.IsContentUri()) {
 661     int fd = OpenContentUriForRead(file_path);
 662     if (fd < 0)
 663       return false;
 664     file_util::ScopedFD scoped_fd(&fd);
 665     if (CallFstat(fd, &file_info) != 0)
 666       return false;
 667   } else {
 668 #endif  // defined(OS_ANDROID)
 669     if (CallStat(file_path.value().c_str(), &file_info) != 0)
 670       return false;
 671 #if defined(OS_ANDROID)
 672   }
 673 #endif  // defined(OS_ANDROID)
 674   results->is_directory = S_ISDIR(file_info.st_mode);
 675   results->size = file_info.st_size;
 676 #if defined(OS_MACOSX)
 677   results->last_modified = Time::FromTimeSpec(file_info.st_mtimespec);
 678   results->last_accessed = Time::FromTimeSpec(file_info.st_atimespec);
 679   results->creation_time = Time::FromTimeSpec(file_info.st_ctimespec);
 680 #elif defined(OS_ANDROID)
 681   results->last_modified = Time::FromTimeT(file_info.st_mtime);
 682   results->last_accessed = Time::FromTimeT(file_info.st_atime);
 683   results->creation_time = Time::FromTimeT(file_info.st_ctime);
 684 #else
 685   results->last_modified = Time::FromTimeSpec(file_info.st_mtim);
 686   results->last_accessed = Time::FromTimeSpec(file_info.st_atim);
 687   results->creation_time = Time::FromTimeSpec(file_info.st_ctim);
 688 #endif
 689   return true;
 690 }
 691
 692 FILE* OpenFile(const FilePath& filename, const char* mode) {
 693   ThreadRestrictions::AssertIOAllowed();
 694   FILE* result = NULL;
 695   do {
 696     result = fopen(filename.value().c_str(), mode);
 697   } while (!result && errno == EINTR);
 698   return result;
 699 }
 700
 701 int ReadFile(const FilePath& filename, char* data, int size) {
 702   ThreadRestrictions::AssertIOAllowed();
 703   int fd = HANDLE_EINTR(open(filename.value().c_str(), O_RDONLY));
 704   if (fd < 0)
 705     return -1;
 706
 707   ssize_t bytes_read = HANDLE_EINTR(read(fd, data, size));
 708   if (int ret = IGNORE_EINTR(close(fd)) < 0)
 709     return ret;
 710   return bytes_read;
 711 }
 712
 713 }  // namespace base
 714
 715 // -----------------------------------------------------------------------------
 716
 717 namespace file_util {
 718
 719 using base::stat_wrapper_t;
 720 using base::CallStat;
 721 using base::CallLstat;
 722 using base::CreateAndOpenFdForTemporaryFile;
 723 using base::DirectoryExists;
 724 using base::FileEnumerator;
 725 using base::FilePath;
 726 using base::MakeAbsoluteFilePath;
 727 using base::VerifySpecificPathControlledByUser;
 728
 729 base::FilePath MakeUniqueDirectory(const base::FilePath& path) {
 730   const int kMaxAttempts = 20;
 731   for (int attempts = 0; attempts < kMaxAttempts; attempts++) {
 732     int uniquifier =
 733         GetUniquePathNumber(path, base::FilePath::StringType());
 734     if (uniquifier < 0)
 735       break;
 736     base::FilePath test_path = (uniquifier == 0) ? path :
 737         path.InsertBeforeExtensionASCII(
 738             base::StringPrintf(" (%d)", uniquifier));
 739     if (mkdir(test_path.value().c_str(), 0777) == 0)
 740       return test_path;
 741     else if (errno != EEXIST)
 742       break;
 743   }
 744   return base::FilePath();
 745 }
 746
 747 FILE* OpenFile(const std::string& filename, const char* mode) {
 748   return OpenFile(FilePath(filename), mode);
 749 }
 750
 751 int WriteFile(const FilePath& filename, const char* data, int size) {
 752   base::ThreadRestrictions::AssertIOAllowed();
 753   int fd = HANDLE_EINTR(creat(filename.value().c_str(), 0666));
 754   if (fd < 0)
 755     return -1;
 756
 757   int bytes_written = WriteFileDescriptor(fd, data, size);
 758   if (int ret = IGNORE_EINTR(close(fd)) < 0)
 759     return ret;
 760   return bytes_written;
 761 }
 762
 763 int WriteFileDescriptor(const int fd, const char* data, int size) {
 764   // Allow for partial writes.
 765   ssize_t bytes_written_total = 0;
 766   for (ssize_t bytes_written_partial = 0; bytes_written_total < size;
 767        bytes_written_total += bytes_written_partial) {
 768     bytes_written_partial =
 769         HANDLE_EINTR(write(fd, data + bytes_written_total,
 770                            size - bytes_written_total));
 771     if (bytes_written_partial < 0)
 772       return -1;
 773   }
 774
 775   return bytes_written_total;
 776 }
 777
 778 int AppendToFile(const FilePath& filename, const char* data, int size) {
 779   base::ThreadRestrictions::AssertIOAllowed();
 780   int fd = HANDLE_EINTR(open(filename.value().c_str(), O_WRONLY | O_APPEND));
 781   if (fd < 0)
 782     return -1;
 783
 784   int bytes_written = WriteFileDescriptor(fd, data, size);
 785   if (int ret = IGNORE_EINTR(close(fd)) < 0)
 786     return ret;
 787   return bytes_written;
 788 }
 789
 790 // Gets the current working directory for the process.
 791 bool GetCurrentDirectory(FilePath* dir) {
 792   // getcwd can return ENOENT, which implies it checks against the disk.
 793   base::ThreadRestrictions::AssertIOAllowed();
 794
 795   char system_buffer[PATH_MAX] = "";
 796   if (!getcwd(system_buffer, sizeof(system_buffer))) {
 797     NOTREACHED();
 798     return false;
 799   }
 800   *dir = FilePath(system_buffer);
 801   return true;
 802 }
 803
 804 // Sets the current working directory for the process.
 805 bool SetCurrentDirectory(const FilePath& path) {
 806   base::ThreadRestrictions::AssertIOAllowed();
 807   int ret = chdir(path.value().c_str());
 808   return !ret;
 809 }
 810
 811 bool VerifyPathControlledByUser(const FilePath& base,
 812                                 const FilePath& path,
 813                                 uid_t owner_uid,
 814                                 const std::set<gid_t>& group_gids) {
 815   if (base != path && !base.IsParent(path)) {
 816      DLOG(ERROR) << "|base| must be a subdirectory of |path|.  base = \""
 817                  << base.value() << "\", path = \"" << path.value() << "\"";
 818      return false;
 819   }
 820
 821   std::vector<FilePath::StringType> base_components;
 822   std::vector<FilePath::StringType> path_components;
 823
 824   base.GetComponents(&base_components);
 825   path.GetComponents(&path_components);
 826
 827   std::vector<FilePath::StringType>::const_iterator ib, ip;
 828   for (ib = base_components.begin(), ip = path_components.begin();
 829        ib != base_components.end(); ++ib, ++ip) {
 830     // |base| must be a subpath of |path|, so all components should match.
 831     // If these CHECKs fail, look at the test that base is a parent of
 832     // path at the top of this function.
 833     DCHECK(ip != path_components.end());
 834     DCHECK(*ip == *ib);
 835   }
 836
 837   FilePath current_path = base;
 838   if (!VerifySpecificPathControlledByUser(current_path, owner_uid, group_gids))
 839     return false;
 840
 841   for (; ip != path_components.end(); ++ip) {
 842     current_path = current_path.Append(*ip);
 843     if (!VerifySpecificPathControlledByUser(
 844             current_path, owner_uid, group_gids))
 845       return false;
 846   }
 847   return true;
 848 }
 849
 850 #if defined(OS_MACOSX) && !defined(OS_IOS)
 851 bool VerifyPathControlledByAdmin(const FilePath& path) {
 852   const unsigned kRootUid = 0;
 853   const FilePath kFileSystemRoot("/");
 854
 855   // The name of the administrator group on mac os.
 856   const char* const kAdminGroupNames[] = {
 857     "admin",
 858     "wheel"
 859   };
 860
 861   // Reading the groups database may touch the file system.
 862   base::ThreadRestrictions::AssertIOAllowed();
 863
 864   std::set<gid_t> allowed_group_ids;
 865   for (int i = 0, ie = arraysize(kAdminGroupNames); i < ie; ++i) {
 866     struct group *group_record = getgrnam(kAdminGroupNames[i]);
 867     if (!group_record) {
 868       DPLOG(ERROR) << "Could not get the group ID of group \""
 869                    << kAdminGroupNames[i] << "\".";
 870       continue;
 871     }
 872
 873     allowed_group_ids.insert(group_record->gr_gid);
 874   }
 875
 876   return VerifyPathControlledByUser(
 877       kFileSystemRoot, path, kRootUid, allowed_group_ids);
 878 }
 879 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 880
 881 int GetMaximumPathComponentLength(const FilePath& path) {
 882   base::ThreadRestrictions::AssertIOAllowed();
 883   return pathconf(path.value().c_str(), _PC_NAME_MAX);
 884 }
 885
 886 }  // namespace file_util
 887
 888 namespace base {
 889 namespace internal {
 890
 891 bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) {
 892   ThreadRestrictions::AssertIOAllowed();
 893   // Windows compatibility: if to_path exists, from_path and to_path
 894   // must be the same type, either both files, or both directories.
 895   stat_wrapper_t to_file_info;
 896   if (CallStat(to_path.value().c_str(), &to_file_info) == 0) {
 897     stat_wrapper_t from_file_info;
 898     if (CallStat(from_path.value().c_str(), &from_file_info) == 0) {
 899       if (S_ISDIR(to_file_info.st_mode) != S_ISDIR(from_file_info.st_mode))
 900         return false;
 901     } else {
 902       return false;
 903     }
 904   }
 905
 906   if (rename(from_path.value().c_str(), to_path.value().c_str()) == 0)
 907     return true;
 908
 909   if (!CopyDirectory(from_path, to_path, true))
 910     return false;
 911
 912   DeleteFile(from_path, true);
 913   return true;
 914 }
 915
 916 #if !defined(OS_MACOSX)
 917 // Mac has its own implementation, this is for all other Posix systems.
 918 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
 919   ThreadRestrictions::AssertIOAllowed();
 920   int infile = HANDLE_EINTR(open(from_path.value().c_str(), O_RDONLY));
 921   if (infile < 0)
 922     return false;
 923
 924   int outfile = HANDLE_EINTR(creat(to_path.value().c_str(), 0666));
 925   if (outfile < 0) {
 926     close(infile);
 927     return false;
 928   }
 929
 930   const size_t kBufferSize = 32768;
 931   std::vector<char> buffer(kBufferSize);
 932   bool result = true;
 933
 934   while (result) {
 935     ssize_t bytes_read = HANDLE_EINTR(read(infile, &buffer[0], buffer.size()));
 936     if (bytes_read < 0) {
 937       result = false;
 938       break;
 939     }
 940     if (bytes_read == 0)
 941       break;
 942     // Allow for partial writes
 943     ssize_t bytes_written_per_read = 0;
 944     do {
 945       ssize_t bytes_written_partial = HANDLE_EINTR(write(
 946           outfile,
 947           &buffer[bytes_written_per_read],
 948           bytes_read - bytes_written_per_read));
 949       if (bytes_written_partial < 0) {
 950         result = false;
 951         break;
 952       }
 953       bytes_written_per_read += bytes_written_partial;
 954     } while (bytes_written_per_read < bytes_read);
 955   }
 956
 957   if (IGNORE_EINTR(close(infile)) < 0)
 958     result = false;
 959   if (IGNORE_EINTR(close(outfile)) < 0)
 960     result = false;
 961
 962   return result;
 963 }
 964 #endif  // !defined(OS_MACOSX)
 965
 966 }  // namespace internal
 967 }  // namespace base