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   DCHECK(to_path.value().find('*') == std::string::npos);
 264   DCHECK(from_path.value().find('*') == std::string::npos);
 265
 266   if (from_path.value().size() >= PATH_MAX) {
 267     return false;
 268   }
 269
 270   // This function does not properly handle destinations within the source
 271   FilePath real_to_path = to_path;
 272   if (PathExists(real_to_path)) {
 273     real_to_path = MakeAbsoluteFilePath(real_to_path);
 274     if (real_to_path.empty())
 275       return false;
 276   } else {
 277     real_to_path = MakeAbsoluteFilePath(real_to_path.DirName());
 278     if (real_to_path.empty())
 279       return false;
 280   }
 281   FilePath real_from_path = MakeAbsoluteFilePath(from_path);
 282   if (real_from_path.empty())
 283     return false;
 284   if (real_to_path.value().size() >= real_from_path.value().size() &&
 285       real_to_path.value().compare(0, real_from_path.value().size(),
 286                                    real_from_path.value()) == 0) {
 287     return false;
 288   }
 289
 290   int traverse_type = FileEnumerator::FILES | FileEnumerator::SHOW_SYM_LINKS;
 291   if (recursive)
 292     traverse_type |= FileEnumerator::DIRECTORIES;
 293   FileEnumerator traversal(from_path, recursive, traverse_type);
 294
 295   // We have to mimic windows behavior here. |to_path| may not exist yet,
 296   // start the loop with |to_path|.
 297   struct stat from_stat;
 298   FilePath current = from_path;
 299   if (stat(from_path.value().c_str(), &from_stat) < 0) {
 300     DLOG(ERROR) << "CopyDirectory() couldn't stat source directory: "
 301                 << from_path.value() << " errno = " << errno;
 302     return false;
 303   }
 304   struct stat to_path_stat;
 305   FilePath from_path_base = from_path;
 306   if (recursive && stat(to_path.value().c_str(), &to_path_stat) == 0 &&
 307       S_ISDIR(to_path_stat.st_mode)) {
 308     // If the destination already exists and is a directory, then the
 309     // top level of source needs to be copied.
 310     from_path_base = from_path.DirName();
 311   }
 312
 313   // The Windows version of this function assumes that non-recursive calls
 314   // will always have a directory for from_path.
 315   // TODO(maruel): This is not necessary anymore.
 316   DCHECK(recursive || S_ISDIR(from_stat.st_mode));
 317
 318   bool success = true;
 319   while (success && !current.empty()) {
 320     // current is the source path, including from_path, so append
 321     // the suffix after from_path to to_path to create the target_path.
 322     FilePath target_path(to_path);
 323     if (from_path_base != current) {
 324       if (!from_path_base.AppendRelativePath(current, &target_path)) {
 325         success = false;
 326         break;
 327       }
 328     }
 329
 330     if (S_ISDIR(from_stat.st_mode)) {
 331       if (mkdir(target_path.value().c_str(), from_stat.st_mode & 01777) != 0 &&
 332           errno != EEXIST) {
 333         DLOG(ERROR) << "CopyDirectory() couldn't create directory: "
 334                     << target_path.value() << " errno = " << errno;
 335         success = false;
 336       }
 337     } else if (S_ISREG(from_stat.st_mode)) {
 338       if (!CopyFile(current, target_path)) {
 339         DLOG(ERROR) << "CopyDirectory() couldn't create file: "
 340                     << target_path.value();
 341         success = false;
 342       }
 343     } else {
 344       DLOG(WARNING) << "CopyDirectory() skipping non-regular file: "
 345                     << current.value();
 346     }
 347
 348     current = traversal.Next();
 349     if (!current.empty())
 350       from_stat = traversal.GetInfo().stat();
 351   }
 352
 353   return success;
 354 }
 355
 356 bool PathExists(const FilePath& path) {
 357   ThreadRestrictions::AssertIOAllowed();
 358 #if defined(OS_ANDROID)
 359   if (path.IsContentUri()) {
 360     return ContentUriExists(path);
 361   }
 362 #endif
 363   return access(path.value().c_str(), F_OK) == 0;
 364 }
 365
 366 bool PathIsWritable(const FilePath& path) {
 367   ThreadRestrictions::AssertIOAllowed();
 368   return access(path.value().c_str(), W_OK) == 0;
 369 }
 370
 371 bool DirectoryExists(const FilePath& path) {
 372   ThreadRestrictions::AssertIOAllowed();
 373   stat_wrapper_t file_info;
 374   if (CallStat(path.value().c_str(), &file_info) == 0)
 375     return S_ISDIR(file_info.st_mode);
 376   return false;
 377 }
 378
 379 bool ReadFromFD(int fd, char* buffer, size_t bytes) {
 380   size_t total_read = 0;
 381   while (total_read < bytes) {
 382     ssize_t bytes_read =
 383         HANDLE_EINTR(read(fd, buffer + total_read, bytes - total_read));
 384     if (bytes_read <= 0)
 385       break;
 386     total_read += bytes_read;
 387   }
 388   return total_read == bytes;
 389 }
 390
 391 bool CreateSymbolicLink(const FilePath& target_path,
 392                         const FilePath& symlink_path) {
 393   DCHECK(!symlink_path.empty());
 394   DCHECK(!target_path.empty());
 395   return ::symlink(target_path.value().c_str(),
 396                    symlink_path.value().c_str()) != -1;
 397 }
 398
 399 bool ReadSymbolicLink(const FilePath& symlink_path, FilePath* target_path) {
 400   DCHECK(!symlink_path.empty());
 401   DCHECK(target_path);
 402   char buf[PATH_MAX];
 403   ssize_t count = ::readlink(symlink_path.value().c_str(), buf, arraysize(buf));
 404
 405   if (count <= 0) {
 406     target_path->clear();
 407     return false;
 408   }
 409
 410   *target_path = FilePath(FilePath::StringType(buf, count));
 411   return true;
 412 }
 413
 414 bool GetPosixFilePermissions(const FilePath& path, int* mode) {
 415   ThreadRestrictions::AssertIOAllowed();
 416   DCHECK(mode);
 417
 418   stat_wrapper_t file_info;
 419   // Uses stat(), because on symbolic link, lstat() does not return valid
 420   // permission bits in st_mode
 421   if (CallStat(path.value().c_str(), &file_info) != 0)
 422     return false;
 423
 424   *mode = file_info.st_mode & FILE_PERMISSION_MASK;
 425   return true;
 426 }
 427
 428 bool SetPosixFilePermissions(const FilePath& path,
 429                              int mode) {
 430   ThreadRestrictions::AssertIOAllowed();
 431   DCHECK((mode & ~FILE_PERMISSION_MASK) == 0);
 432
 433   // Calls stat() so that we can preserve the higher bits like S_ISGID.
 434   stat_wrapper_t stat_buf;
 435   if (CallStat(path.value().c_str(), &stat_buf) != 0)
 436     return false;
 437
 438   // Clears the existing permission bits, and adds the new ones.
 439   mode_t updated_mode_bits = stat_buf.st_mode & ~FILE_PERMISSION_MASK;
 440   updated_mode_bits |= mode & FILE_PERMISSION_MASK;
 441
 442   if (HANDLE_EINTR(chmod(path.value().c_str(), updated_mode_bits)) != 0)
 443     return false;
 444
 445   return true;
 446 }
 447
 448 #if !defined(OS_MACOSX)
 449 // This is implemented in file_util_mac.mm for Mac.
 450 bool GetTempDir(FilePath* path) {
 451   const char* tmp = getenv("TMPDIR");
 452   if (tmp) {
 453     *path = FilePath(tmp);
 454   } else {
 455 #if defined(OS_ANDROID)
 456     return PathService::Get(base::DIR_CACHE, path);
 457 #else
 458     *path = FilePath("/tmp");
 459 #endif
 460   }
 461   return true;
 462 }
 463 #endif  // !defined(OS_MACOSX)
 464
 465 #if !defined(OS_MACOSX) && !defined(OS_ANDROID)
 466 // This is implemented in file_util_mac.mm and file_util_android.cc for those
 467 // platforms.
 468 bool GetShmemTempDir(bool executable, FilePath* path) {
 469 #if defined(OS_LINUX)
 470   bool use_dev_shm = true;
 471   if (executable) {
 472     static const bool s_dev_shm_executable = DetermineDevShmExecutable();
 473     use_dev_shm = s_dev_shm_executable;
 474   }
 475   if (use_dev_shm) {
 476     *path = FilePath("/dev/shm");
 477     return true;
 478   }
 479 #endif
 480   return GetTempDir(path);
 481 }
 482 #endif  // !defined(OS_MACOSX) && !defined(OS_ANDROID)
 483
 484 #if !defined(OS_MACOSX)
 485 FilePath GetHomeDir() {
 486 #if defined(OS_CHROMEOS)
 487   if (SysInfo::IsRunningOnChromeOS())
 488     return FilePath("/home/chronos/user");
 489 #endif
 490
 491   const char* home_dir = getenv("HOME");
 492   if (home_dir && home_dir[0])
 493     return FilePath(home_dir);
 494
 495 #if defined(OS_ANDROID)
 496   DLOG(WARNING) << "OS_ANDROID: Home directory lookup not yet implemented.";
 497 #elif defined(USE_GLIB) && !defined(OS_CHROMEOS)
 498   // g_get_home_dir calls getpwent, which can fall through to LDAP calls.
 499   ThreadRestrictions::AssertIOAllowed();
 500
 501   home_dir = g_get_home_dir();
 502   if (home_dir && home_dir[0])
 503     return FilePath(home_dir);
 504 #endif
 505
 506   FilePath rv;
 507   if (GetTempDir(&rv))
 508     return rv;
 509
 510   // Last resort.
 511   return FilePath("/tmp");
 512 }
 513 #endif  // !defined(OS_MACOSX)
 514
 515 bool CreateTemporaryFile(FilePath* path) {
 516   ThreadRestrictions::AssertIOAllowed();  // For call to close().
 517   FilePath directory;
 518   if (!GetTempDir(&directory))
 519     return false;
 520   int fd = CreateAndOpenFdForTemporaryFile(directory, path);
 521   if (fd < 0)
 522     return false;
 523   close(fd);
 524   return true;
 525 }
 526
 527 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
 528   FilePath directory;
 529   if (!GetShmemTempDir(executable, &directory))
 530     return NULL;
 531
 532   return CreateAndOpenTemporaryFileInDir(directory, path);
 533 }
 534
 535 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
 536   int fd = CreateAndOpenFdForTemporaryFile(dir, path);
 537   if (fd < 0)
 538     return NULL;
 539
 540   FILE* file = fdopen(fd, "a+");
 541   if (!file)
 542     close(fd);
 543   return file;
 544 }
 545
 546 bool CreateTemporaryFileInDir(const FilePath& dir, FilePath* temp_file) {
 547   ThreadRestrictions::AssertIOAllowed();  // For call to close().
 548   int fd = CreateAndOpenFdForTemporaryFile(dir, temp_file);
 549   return ((fd >= 0) && !IGNORE_EINTR(close(fd)));
 550 }
 551
 552 static bool CreateTemporaryDirInDirImpl(const FilePath& base_dir,
 553                                         const FilePath::StringType& name_tmpl,
 554                                         FilePath* new_dir) {
 555   ThreadRestrictions::AssertIOAllowed();  // For call to mkdtemp().
 556   DCHECK(name_tmpl.find("XXXXXX") != FilePath::StringType::npos)
 557       << "Directory name template must contain \"XXXXXX\".";
 558
 559   FilePath sub_dir = base_dir.Append(name_tmpl);
 560   std::string sub_dir_string = sub_dir.value();
 561
 562   // this should be OK since mkdtemp just replaces characters in place
 563   char* buffer = const_cast<char*>(sub_dir_string.c_str());
 564   char* dtemp = mkdtemp(buffer);
 565   if (!dtemp) {
 566     DPLOG(ERROR) << "mkdtemp";
 567     return false;
 568   }
 569   *new_dir = FilePath(dtemp);
 570   return true;
 571 }
 572
 573 bool CreateTemporaryDirInDir(const FilePath& base_dir,
 574                              const FilePath::StringType& prefix,
 575                              FilePath* new_dir) {
 576   FilePath::StringType mkdtemp_template = prefix;
 577   mkdtemp_template.append(FILE_PATH_LITERAL("XXXXXX"));
 578   return CreateTemporaryDirInDirImpl(base_dir, mkdtemp_template, new_dir);
 579 }
 580
 581 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 582                             FilePath* new_temp_path) {
 583   FilePath tmpdir;
 584   if (!GetTempDir(&tmpdir))
 585     return false;
 586
 587   return CreateTemporaryDirInDirImpl(tmpdir, TempFileName(), new_temp_path);
 588 }
 589
 590 bool CreateDirectoryAndGetError(const FilePath& full_path,
 591                                 File::Error* error) {
 592   ThreadRestrictions::AssertIOAllowed();  // For call to mkdir().
 593   std::vector<FilePath> subpaths;
 594
 595   // Collect a list of all parent directories.
 596   FilePath last_path = full_path;
 597   subpaths.push_back(full_path);
 598   for (FilePath path = full_path.DirName();
 599        path.value() != last_path.value(); path = path.DirName()) {
 600     subpaths.push_back(path);
 601     last_path = path;
 602   }
 603
 604   // Iterate through the parents and create the missing ones.
 605   for (std::vector<FilePath>::reverse_iterator i = subpaths.rbegin();
 606        i != subpaths.rend(); ++i) {
 607     if (DirectoryExists(*i))
 608       continue;
 609     if (mkdir(i->value().c_str(), 0700) == 0)
 610       continue;
 611     // Mkdir failed, but it might have failed with EEXIST, or some other error
 612     // due to the the directory appearing out of thin air. This can occur if
 613     // two processes are trying to create the same file system tree at the same
 614     // time. Check to see if it exists and make sure it is a directory.
 615     int saved_errno = errno;
 616     if (!DirectoryExists(*i)) {
 617       if (error)
 618         *error = File::OSErrorToFileError(saved_errno);
 619       return false;
 620     }
 621   }
 622   return true;
 623 }
 624
 625 bool NormalizeFilePath(const FilePath& path, FilePath* normalized_path) {
 626   FilePath real_path_result;
 627   if (!RealPath(path, &real_path_result))
 628     return false;
 629
 630   // To be consistant with windows, fail if |real_path_result| is a
 631   // directory.
 632   stat_wrapper_t file_info;
 633   if (CallStat(real_path_result.value().c_str(), &file_info) != 0 ||
 634       S_ISDIR(file_info.st_mode))
 635     return false;
 636
 637   *normalized_path = real_path_result;
 638   return true;
 639 }
 640
 641 // TODO(rkc): Refactor GetFileInfo and FileEnumerator to handle symlinks
 642 // correctly. http://code.google.com/p/chromium-os/issues/detail?id=15948
 643 bool IsLink(const FilePath& file_path) {
 644   stat_wrapper_t st;
 645   // If we can't lstat the file, it's safe to assume that the file won't at
 646   // least be a 'followable' link.
 647   if (CallLstat(file_path.value().c_str(), &st) != 0)
 648     return false;
 649
 650   if (S_ISLNK(st.st_mode))
 651     return true;
 652   else
 653     return false;
 654 }
 655
 656 bool GetFileInfo(const FilePath& file_path, File::Info* results) {
 657   stat_wrapper_t file_info;
 658 #if defined(OS_ANDROID)
 659   if (file_path.IsContentUri()) {
 660     int fd = OpenContentUriForRead(file_path);
 661     if (fd < 0)
 662       return false;
 663     file_util::ScopedFD scoped_fd(&fd);
 664     if (CallFstat(fd, &file_info) != 0)
 665       return false;
 666   } else {
 667 #endif  // defined(OS_ANDROID)
 668     if (CallStat(file_path.value().c_str(), &file_info) != 0)
 669       return false;
 670 #if defined(OS_ANDROID)
 671   }
 672 #endif  // defined(OS_ANDROID)
 673   results->is_directory = S_ISDIR(file_info.st_mode);
 674   results->size = file_info.st_size;
 675 #if defined(OS_MACOSX)
 676   results->last_modified = Time::FromTimeSpec(file_info.st_mtimespec);
 677   results->last_accessed = Time::FromTimeSpec(file_info.st_atimespec);
 678   results->creation_time = Time::FromTimeSpec(file_info.st_ctimespec);
 679 #elif defined(OS_ANDROID)
 680   results->last_modified = Time::FromTimeT(file_info.st_mtime);
 681   results->last_accessed = Time::FromTimeT(file_info.st_atime);
 682   results->creation_time = Time::FromTimeT(file_info.st_ctime);
 683 #else
 684   results->last_modified = Time::FromTimeSpec(file_info.st_mtim);
 685   results->last_accessed = Time::FromTimeSpec(file_info.st_atim);
 686   results->creation_time = Time::FromTimeSpec(file_info.st_ctim);
 687 #endif
 688   return true;
 689 }
 690
 691 FILE* OpenFile(const FilePath& filename, const char* mode) {
 692   ThreadRestrictions::AssertIOAllowed();
 693   FILE* result = NULL;
 694   do {
 695     result = fopen(filename.value().c_str(), mode);
 696   } while (!result && errno == EINTR);
 697   return result;
 698 }
 699
 700 int ReadFile(const FilePath& filename, char* data, int size) {
 701   ThreadRestrictions::AssertIOAllowed();
 702   int fd = HANDLE_EINTR(open(filename.value().c_str(), O_RDONLY));
 703   if (fd < 0)
 704     return -1;
 705
 706   ssize_t bytes_read = HANDLE_EINTR(read(fd, data, size));
 707   if (int ret = IGNORE_EINTR(close(fd)) < 0)
 708     return ret;
 709   return bytes_read;
 710 }
 711
 712 }  // namespace base
 713
 714 // -----------------------------------------------------------------------------
 715
 716 namespace file_util {
 717
 718 using base::stat_wrapper_t;
 719 using base::CallStat;
 720 using base::CallLstat;
 721 using base::CreateAndOpenFdForTemporaryFile;
 722 using base::DirectoryExists;
 723 using base::FileEnumerator;
 724 using base::FilePath;
 725 using base::MakeAbsoluteFilePath;
 726 using base::VerifySpecificPathControlledByUser;
 727
 728 base::FilePath MakeUniqueDirectory(const base::FilePath& path) {
 729   const int kMaxAttempts = 20;
 730   for (int attempts = 0; attempts < kMaxAttempts; attempts++) {
 731     int uniquifier =
 732         GetUniquePathNumber(path, base::FilePath::StringType());
 733     if (uniquifier < 0)
 734       break;
 735     base::FilePath test_path = (uniquifier == 0) ? path :
 736         path.InsertBeforeExtensionASCII(
 737             base::StringPrintf(" (%d)", uniquifier));
 738     if (mkdir(test_path.value().c_str(), 0777) == 0)
 739       return test_path;
 740     else if (errno != EEXIST)
 741       break;
 742   }
 743   return base::FilePath();
 744 }
 745
 746 FILE* OpenFile(const std::string& filename, const char* mode) {
 747   return OpenFile(FilePath(filename), mode);
 748 }
 749
 750 int WriteFile(const FilePath& filename, const char* data, int size) {
 751   base::ThreadRestrictions::AssertIOAllowed();
 752   int fd = HANDLE_EINTR(creat(filename.value().c_str(), 0666));
 753   if (fd < 0)
 754     return -1;
 755
 756   int bytes_written = WriteFileDescriptor(fd, data, size);
 757   if (int ret = IGNORE_EINTR(close(fd)) < 0)
 758     return ret;
 759   return bytes_written;
 760 }
 761
 762 int WriteFileDescriptor(const int fd, const char* data, int size) {
 763   // Allow for partial writes.
 764   ssize_t bytes_written_total = 0;
 765   for (ssize_t bytes_written_partial = 0; bytes_written_total < size;
 766        bytes_written_total += bytes_written_partial) {
 767     bytes_written_partial =
 768         HANDLE_EINTR(write(fd, data + bytes_written_total,
 769                            size - bytes_written_total));
 770     if (bytes_written_partial < 0)
 771       return -1;
 772   }
 773
 774   return bytes_written_total;
 775 }
 776
 777 int AppendToFile(const FilePath& filename, const char* data, int size) {
 778   base::ThreadRestrictions::AssertIOAllowed();
 779   int fd = HANDLE_EINTR(open(filename.value().c_str(), O_WRONLY | O_APPEND));
 780   if (fd < 0)
 781     return -1;
 782
 783   int bytes_written = WriteFileDescriptor(fd, data, size);
 784   if (int ret = IGNORE_EINTR(close(fd)) < 0)
 785     return ret;
 786   return bytes_written;
 787 }
 788
 789 // Gets the current working directory for the process.
 790 bool GetCurrentDirectory(FilePath* dir) {
 791   // getcwd can return ENOENT, which implies it checks against the disk.
 792   base::ThreadRestrictions::AssertIOAllowed();
 793
 794   char system_buffer[PATH_MAX] = "";
 795   if (!getcwd(system_buffer, sizeof(system_buffer))) {
 796     NOTREACHED();
 797     return false;
 798   }
 799   *dir = FilePath(system_buffer);
 800   return true;
 801 }
 802
 803 // Sets the current working directory for the process.
 804 bool SetCurrentDirectory(const FilePath& path) {
 805   base::ThreadRestrictions::AssertIOAllowed();
 806   int ret = chdir(path.value().c_str());
 807   return !ret;
 808 }
 809
 810 bool VerifyPathControlledByUser(const FilePath& base,
 811                                 const FilePath& path,
 812                                 uid_t owner_uid,
 813                                 const std::set<gid_t>& group_gids) {
 814   if (base != path && !base.IsParent(path)) {
 815      DLOG(ERROR) << "|base| must be a subdirectory of |path|.  base = \""
 816                  << base.value() << "\", path = \"" << path.value() << "\"";
 817      return false;
 818   }
 819
 820   std::vector<FilePath::StringType> base_components;
 821   std::vector<FilePath::StringType> path_components;
 822
 823   base.GetComponents(&base_components);
 824   path.GetComponents(&path_components);
 825
 826   std::vector<FilePath::StringType>::const_iterator ib, ip;
 827   for (ib = base_components.begin(), ip = path_components.begin();
 828        ib != base_components.end(); ++ib, ++ip) {
 829     // |base| must be a subpath of |path|, so all components should match.
 830     // If these CHECKs fail, look at the test that base is a parent of
 831     // path at the top of this function.
 832     DCHECK(ip != path_components.end());
 833     DCHECK(*ip == *ib);
 834   }
 835
 836   FilePath current_path = base;
 837   if (!VerifySpecificPathControlledByUser(current_path, owner_uid, group_gids))
 838     return false;
 839
 840   for (; ip != path_components.end(); ++ip) {
 841     current_path = current_path.Append(*ip);
 842     if (!VerifySpecificPathControlledByUser(
 843             current_path, owner_uid, group_gids))
 844       return false;
 845   }
 846   return true;
 847 }
 848
 849 #if defined(OS_MACOSX) && !defined(OS_IOS)
 850 bool VerifyPathControlledByAdmin(const FilePath& path) {
 851   const unsigned kRootUid = 0;
 852   const FilePath kFileSystemRoot("/");
 853
 854   // The name of the administrator group on mac os.
 855   const char* const kAdminGroupNames[] = {
 856     "admin",
 857     "wheel"
 858   };
 859
 860   // Reading the groups database may touch the file system.
 861   base::ThreadRestrictions::AssertIOAllowed();
 862
 863   std::set<gid_t> allowed_group_ids;
 864   for (int i = 0, ie = arraysize(kAdminGroupNames); i < ie; ++i) {
 865     struct group *group_record = getgrnam(kAdminGroupNames[i]);
 866     if (!group_record) {
 867       DPLOG(ERROR) << "Could not get the group ID of group \""
 868                    << kAdminGroupNames[i] << "\".";
 869       continue;
 870     }
 871
 872     allowed_group_ids.insert(group_record->gr_gid);
 873   }
 874
 875   return VerifyPathControlledByUser(
 876       kFileSystemRoot, path, kRootUid, allowed_group_ids);
 877 }
 878 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
 879
 880 int GetMaximumPathComponentLength(const FilePath& path) {
 881   base::ThreadRestrictions::AssertIOAllowed();
 882   return pathconf(path.value().c_str(), _PC_NAME_MAX);
 883 }
 884
 885 }  // namespace file_util
 886
 887 namespace base {
 888 namespace internal {
 889
 890 bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) {
 891   ThreadRestrictions::AssertIOAllowed();
 892   // Windows compatibility: if to_path exists, from_path and to_path
 893   // must be the same type, either both files, or both directories.
 894   stat_wrapper_t to_file_info;
 895   if (CallStat(to_path.value().c_str(), &to_file_info) == 0) {
 896     stat_wrapper_t from_file_info;
 897     if (CallStat(from_path.value().c_str(), &from_file_info) == 0) {
 898       if (S_ISDIR(to_file_info.st_mode) != S_ISDIR(from_file_info.st_mode))
 899         return false;
 900     } else {
 901       return false;
 902     }
 903   }
 904
 905   if (rename(from_path.value().c_str(), to_path.value().c_str()) == 0)
 906     return true;
 907
 908   if (!CopyDirectory(from_path, to_path, true))
 909     return false;
 910
 911   DeleteFile(from_path, true);
 912   return true;
 913 }
 914
 915 #if !defined(OS_MACOSX)
 916 // Mac has its own implementation, this is for all other Posix systems.
 917 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
 918   ThreadRestrictions::AssertIOAllowed();
 919   int infile = HANDLE_EINTR(open(from_path.value().c_str(), O_RDONLY));
 920   if (infile < 0)
 921     return false;
 922
 923   int outfile = HANDLE_EINTR(creat(to_path.value().c_str(), 0666));
 924   if (outfile < 0) {
 925     close(infile);
 926     return false;
 927   }
 928
 929   const size_t kBufferSize = 32768;
 930   std::vector<char> buffer(kBufferSize);
 931   bool result = true;
 932
 933   while (result) {
 934     ssize_t bytes_read = HANDLE_EINTR(read(infile, &buffer[0], buffer.size()));
 935     if (bytes_read < 0) {
 936       result = false;
 937       break;
 938     }
 939     if (bytes_read == 0)
 940       break;
 941     // Allow for partial writes
 942     ssize_t bytes_written_per_read = 0;
 943     do {
 944       ssize_t bytes_written_partial = HANDLE_EINTR(write(
 945           outfile,
 946           &buffer[bytes_written_per_read],
 947           bytes_read - bytes_written_per_read));
 948       if (bytes_written_partial < 0) {
 949         result = false;
 950         break;
 951       }
 952       bytes_written_per_read += bytes_written_partial;
 953     } while (bytes_written_per_read < bytes_read);
 954   }
 955
 956   if (IGNORE_EINTR(close(infile)) < 0)
 957     result = false;
 958   if (IGNORE_EINTR(close(outfile)) < 0)
 959     result = false;
 960
 961   return result;
 962 }
 963 #endif  // !defined(OS_MACOSX)
 964
 965 }  // namespace internal
 966 }  // namespace base