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 <fnmatch.h>
  11 #include <libgen.h>
  12 #include <limits.h>
  13 #include <stdio.h>
  14 #include <stdlib.h>
  15 #include <string.h>
  16 #include <sys/errno.h>
  17 #include <sys/mman.h>
  18 #include <sys/param.h>
  19 #include <sys/stat.h>
  20 #include <sys/time.h>
  21 #include <sys/types.h>
  22 #include <time.h>
  23 #include <unistd.h>
  24
  25 #if defined(OS_MACOSX)
  26 #include <AvailabilityMacros.h>
  27 #include "base/mac/foundation_util.h"
  28 #elif !defined(OS_ANDROID)
  29 #include <glib.h>
  30 #endif
  31
  32 #include <fstream>
  33
  34 #include "base/basictypes.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/string_util.h"
  43 #include "base/stringprintf.h"
  44 #include "base/strings/sys_string_conversions.h"
  45 #include "base/threading/thread_restrictions.h"
  46 #include "base/time.h"
  47 #include "base/utf_string_conversions.h"
  48
  49 #if defined(OS_ANDROID)
  50 #include "base/os_compat_android.h"
  51 #endif
  52
  53 #if !defined(OS_IOS)
  54 #include <grp.h>
  55 #endif
  56
  57 #if defined(OS_CHROMEOS)
  58 #include "base/chromeos/chromeos_version.h"
  59 #endif
  60
  61 using base::FilePath;
  62 using base::MakeAbsoluteFilePath;
  63
  64 namespace base {
  65
  66 FilePath MakeAbsoluteFilePath(const FilePath& input) {
  67   base::ThreadRestrictions::AssertIOAllowed();
  68   char full_path[PATH_MAX];
  69   if (realpath(input.value().c_str(), full_path) == NULL)
  70     return FilePath();
  71   return FilePath(full_path);
  72 }
  73
  74 }  // namespace base
  75
  76 namespace file_util {
  77
  78 namespace {
  79
  80 #if defined(OS_BSD) || defined(OS_MACOSX)
  81 typedef struct stat stat_wrapper_t;
  82 static int CallStat(const char *path, stat_wrapper_t *sb) {
  83   base::ThreadRestrictions::AssertIOAllowed();
  84   return stat(path, sb);
  85 }
  86 static int CallLstat(const char *path, stat_wrapper_t *sb) {
  87   base::ThreadRestrictions::AssertIOAllowed();
  88   return lstat(path, sb);
  89 }
  90 #else
  91 typedef struct stat64 stat_wrapper_t;
  92 static int CallStat(const char *path, stat_wrapper_t *sb) {
  93   base::ThreadRestrictions::AssertIOAllowed();
  94   return stat64(path, sb);
  95 }
  96 static int CallLstat(const char *path, stat_wrapper_t *sb) {
  97   base::ThreadRestrictions::AssertIOAllowed();
  98   return lstat64(path, sb);
  99 }
 100 #endif
 101
 102 // Helper for NormalizeFilePath(), defined below.
 103 bool RealPath(const FilePath& path, FilePath* real_path) {
 104   base::ThreadRestrictions::AssertIOAllowed();  // For realpath().
 105   FilePath::CharType buf[PATH_MAX];
 106   if (!realpath(path.value().c_str(), buf))
 107     return false;
 108
 109   *real_path = FilePath(buf);
 110   return true;
 111 }
 112
 113 // Helper for VerifyPathControlledByUser.
 114 bool VerifySpecificPathControlledByUser(const FilePath& path,
 115                                         uid_t owner_uid,
 116                                         const std::set<gid_t>& group_gids) {
 117   stat_wrapper_t stat_info;
 118   if (CallLstat(path.value().c_str(), &stat_info) != 0) {
 119     DPLOG(ERROR) << "Failed to get information on path "
 120                  << path.value();
 121     return false;
 122   }
 123
 124   if (S_ISLNK(stat_info.st_mode)) {
 125     DLOG(ERROR) << "Path " << path.value()
 126                << " is a symbolic link.";
 127     return false;
 128   }
 129
 130   if (stat_info.st_uid != owner_uid) {
 131     DLOG(ERROR) << "Path " << path.value()
 132                 << " is owned by the wrong user.";
 133     return false;
 134   }
 135
 136   if ((stat_info.st_mode & S_IWGRP) &&
 137       !ContainsKey(group_gids, stat_info.st_gid)) {
 138     DLOG(ERROR) << "Path " << path.value()
 139                 << " is writable by an unprivileged group.";
 140     return false;
 141   }
 142
 143   if (stat_info.st_mode & S_IWOTH) {
 144     DLOG(ERROR) << "Path " << path.value()
 145                 << " is writable by any user.";
 146     return false;
 147   }
 148
 149   return true;
 150 }
 151
 152 }  // namespace
 153
 154 static std::string TempFileName() {
 155 #if defined(OS_MACOSX)
 156   return base::StringPrintf(".%s.XXXXXX", base::mac::BaseBundleID());
 157 #endif
 158
 159 #if defined(GOOGLE_CHROME_BUILD)
 160   return std::string(".com.google.Chrome.XXXXXX");
 161 #else
 162   return std::string(".org.chromium.Chromium.XXXXXX");
 163 #endif
 164 }
 165
 166 // TODO(erikkay): The Windows version of this accepts paths like "foo/bar/*"
 167 // which works both with and without the recursive flag.  I'm not sure we need
 168 // that functionality. If not, remove from file_util_win.cc, otherwise add it
 169 // here.
 170 bool Delete(const FilePath& path, bool recursive) {
 171   base::ThreadRestrictions::AssertIOAllowed();
 172   const char* path_str = path.value().c_str();
 173   stat_wrapper_t file_info;
 174   int test = CallLstat(path_str, &file_info);
 175   if (test != 0) {
 176     // The Windows version defines this condition as success.
 177     bool ret = (errno == ENOENT || errno == ENOTDIR);
 178     return ret;
 179   }
 180   if (!S_ISDIR(file_info.st_mode))
 181     return (unlink(path_str) == 0);
 182   if (!recursive)
 183     return (rmdir(path_str) == 0);
 184
 185   bool success = true;
 186   std::stack<std::string> directories;
 187   directories.push(path.value());
 188   FileEnumerator traversal(path, true,
 189       FileEnumerator::FILES | FileEnumerator::DIRECTORIES |
 190       FileEnumerator::SHOW_SYM_LINKS);
 191   for (FilePath current = traversal.Next(); success && !current.empty();
 192        current = traversal.Next()) {
 193     FileEnumerator::FindInfo info;
 194     traversal.GetFindInfo(&info);
 195
 196     if (S_ISDIR(info.stat.st_mode))
 197       directories.push(current.value());
 198     else
 199       success = (unlink(current.value().c_str()) == 0);
 200   }
 201
 202   while (success && !directories.empty()) {
 203     FilePath dir = FilePath(directories.top());
 204     directories.pop();
 205     success = (rmdir(dir.value().c_str()) == 0);
 206   }
 207   return success;
 208 }
 209
 210 bool MoveUnsafe(const FilePath& from_path, const FilePath& to_path) {
 211   base::ThreadRestrictions::AssertIOAllowed();
 212   // Windows compatibility: if to_path exists, from_path and to_path
 213   // must be the same type, either both files, or both directories.
 214   stat_wrapper_t to_file_info;
 215   if (CallStat(to_path.value().c_str(), &to_file_info) == 0) {
 216     stat_wrapper_t from_file_info;
 217     if (CallStat(from_path.value().c_str(), &from_file_info) == 0) {
 218       if (S_ISDIR(to_file_info.st_mode) != S_ISDIR(from_file_info.st_mode))
 219         return false;
 220     } else {
 221       return false;
 222     }
 223   }
 224
 225   if (rename(from_path.value().c_str(), to_path.value().c_str()) == 0)
 226     return true;
 227
 228   if (!CopyDirectory(from_path, to_path, true))
 229     return false;
 230
 231   Delete(from_path, true);
 232   return true;
 233 }
 234
 235 bool ReplaceFile(const FilePath& from_path, const FilePath& to_path) {
 236   base::ThreadRestrictions::AssertIOAllowed();
 237   return (rename(from_path.value().c_str(), to_path.value().c_str()) == 0);
 238 }
 239
 240 bool CopyDirectory(const FilePath& from_path,
 241                    const FilePath& to_path,
 242                    bool recursive) {
 243   base::ThreadRestrictions::AssertIOAllowed();
 244   // Some old callers of CopyDirectory want it to support wildcards.
 245   // After some discussion, we decided to fix those callers.
 246   // Break loudly here if anyone tries to do this.
 247   // TODO(evanm): remove this once we're sure it's ok.
 248   DCHECK(to_path.value().find('*') == std::string::npos);
 249   DCHECK(from_path.value().find('*') == std::string::npos);
 250
 251   char top_dir[PATH_MAX];
 252   if (base::strlcpy(top_dir, from_path.value().c_str(),
 253                     arraysize(top_dir)) >= arraysize(top_dir)) {
 254     return false;
 255   }
 256
 257   // This function does not properly handle destinations within the source
 258   FilePath real_to_path = to_path;
 259   if (PathExists(real_to_path)) {
 260     real_to_path = MakeAbsoluteFilePath(real_to_path);
 261     if (real_to_path.empty())
 262       return false;
 263   } else {
 264     real_to_path = MakeAbsoluteFilePath(real_to_path.DirName());
 265     if (real_to_path.empty())
 266       return false;
 267   }
 268   FilePath real_from_path = MakeAbsoluteFilePath(from_path);
 269   if (real_from_path.empty())
 270     return false;
 271   if (real_to_path.value().size() >= real_from_path.value().size() &&
 272       real_to_path.value().compare(0, real_from_path.value().size(),
 273       real_from_path.value()) == 0)
 274     return false;
 275
 276   bool success = true;
 277   int traverse_type = FileEnumerator::FILES | FileEnumerator::SHOW_SYM_LINKS;
 278   if (recursive)
 279     traverse_type |= FileEnumerator::DIRECTORIES;
 280   FileEnumerator traversal(from_path, recursive, traverse_type);
 281
 282   // We have to mimic windows behavior here. |to_path| may not exist yet,
 283   // start the loop with |to_path|.
 284   FileEnumerator::FindInfo info;
 285   FilePath current = from_path;
 286   if (stat(from_path.value().c_str(), &info.stat) < 0) {
 287     DLOG(ERROR) << "CopyDirectory() couldn't stat source directory: "
 288                 << from_path.value() << " errno = " << errno;
 289     success = false;
 290   }
 291   struct stat to_path_stat;
 292   FilePath from_path_base = from_path;
 293   if (recursive && stat(to_path.value().c_str(), &to_path_stat) == 0 &&
 294       S_ISDIR(to_path_stat.st_mode)) {
 295     // If the destination already exists and is a directory, then the
 296     // top level of source needs to be copied.
 297     from_path_base = from_path.DirName();
 298   }
 299
 300   // The Windows version of this function assumes that non-recursive calls
 301   // will always have a directory for from_path.
 302   DCHECK(recursive || S_ISDIR(info.stat.st_mode));
 303
 304   while (success && !current.empty()) {
 305     // current is the source path, including from_path, so append
 306     // the suffix after from_path to to_path to create the target_path.
 307     FilePath target_path(to_path);
 308     if (from_path_base != current) {
 309       if (!from_path_base.AppendRelativePath(current, &target_path)) {
 310         success = false;
 311         break;
 312       }
 313     }
 314
 315     if (S_ISDIR(info.stat.st_mode)) {
 316       if (mkdir(target_path.value().c_str(), info.stat.st_mode & 01777) != 0 &&
 317           errno != EEXIST) {
 318         DLOG(ERROR) << "CopyDirectory() couldn't create directory: "
 319                     << target_path.value() << " errno = " << errno;
 320         success = false;
 321       }
 322     } else if (S_ISREG(info.stat.st_mode)) {
 323       if (!CopyFile(current, target_path)) {
 324         DLOG(ERROR) << "CopyDirectory() couldn't create file: "
 325                     << target_path.value();
 326         success = false;
 327       }
 328     } else {
 329       DLOG(WARNING) << "CopyDirectory() skipping non-regular file: "
 330                     << current.value();
 331     }
 332
 333     current = traversal.Next();
 334     traversal.GetFindInfo(&info);
 335   }
 336
 337   return success;
 338 }
 339
 340 bool PathExists(const FilePath& path) {
 341   base::ThreadRestrictions::AssertIOAllowed();
 342   return access(path.value().c_str(), F_OK) == 0;
 343 }
 344
 345 bool PathIsWritable(const FilePath& path) {
 346   base::ThreadRestrictions::AssertIOAllowed();
 347   return access(path.value().c_str(), W_OK) == 0;
 348 }
 349
 350 bool DirectoryExists(const FilePath& path) {
 351   base::ThreadRestrictions::AssertIOAllowed();
 352   stat_wrapper_t file_info;
 353   if (CallStat(path.value().c_str(), &file_info) == 0)
 354     return S_ISDIR(file_info.st_mode);
 355   return false;
 356 }
 357
 358 bool ReadFromFD(int fd, char* buffer, size_t bytes) {
 359   size_t total_read = 0;
 360   while (total_read < bytes) {
 361     ssize_t bytes_read =
 362         HANDLE_EINTR(read(fd, buffer + total_read, bytes - total_read));
 363     if (bytes_read <= 0)
 364       break;
 365     total_read += bytes_read;
 366   }
 367   return total_read == bytes;
 368 }
 369
 370 bool CreateSymbolicLink(const FilePath& target_path,
 371                         const FilePath& symlink_path) {
 372   DCHECK(!symlink_path.empty());
 373   DCHECK(!target_path.empty());
 374   return ::symlink(target_path.value().c_str(),
 375                    symlink_path.value().c_str()) != -1;
 376 }
 377
 378 bool ReadSymbolicLink(const FilePath& symlink_path,
 379                       FilePath* target_path) {
 380   DCHECK(!symlink_path.empty());
 381   DCHECK(target_path);
 382   char buf[PATH_MAX];
 383   ssize_t count = ::readlink(symlink_path.value().c_str(), buf, arraysize(buf));
 384
 385   if (count <= 0) {
 386     target_path->clear();
 387     return false;
 388   }
 389
 390   *target_path = FilePath(FilePath::StringType(buf, count));
 391   return true;
 392 }
 393
 394 bool GetPosixFilePermissions(const FilePath& path, int* mode) {
 395   base::ThreadRestrictions::AssertIOAllowed();
 396   DCHECK(mode);
 397
 398   stat_wrapper_t file_info;
 399   // Uses stat(), because on symbolic link, lstat() does not return valid
 400   // permission bits in st_mode
 401   if (CallStat(path.value().c_str(), &file_info) != 0)
 402     return false;
 403
 404   *mode = file_info.st_mode & FILE_PERMISSION_MASK;
 405   return true;
 406 }
 407
 408 bool SetPosixFilePermissions(const FilePath& path,
 409                              int mode) {
 410   base::ThreadRestrictions::AssertIOAllowed();
 411   DCHECK((mode & ~FILE_PERMISSION_MASK) == 0);
 412
 413   // Calls stat() so that we can preserve the higher bits like S_ISGID.
 414   stat_wrapper_t stat_buf;
 415   if (CallStat(path.value().c_str(), &stat_buf) != 0)
 416     return false;
 417
 418   // Clears the existing permission bits, and adds the new ones.
 419   mode_t updated_mode_bits = stat_buf.st_mode & ~FILE_PERMISSION_MASK;
 420   updated_mode_bits |= mode & FILE_PERMISSION_MASK;
 421
 422   if (HANDLE_EINTR(chmod(path.value().c_str(), updated_mode_bits)) != 0)
 423     return false;
 424
 425   return true;
 426 }
 427
 428 // Creates and opens a temporary file in |directory|, returning the
 429 // file descriptor. |path| is set to the temporary file path.
 430 // This function does NOT unlink() the file.
 431 int CreateAndOpenFdForTemporaryFile(FilePath directory, FilePath* path) {
 432   base::ThreadRestrictions::AssertIOAllowed();  // For call to mkstemp().
 433   *path = directory.Append(TempFileName());
 434   const std::string& tmpdir_string = path->value();
 435   // this should be OK since mkstemp just replaces characters in place
 436   char* buffer = const_cast<char*>(tmpdir_string.c_str());
 437
 438   return HANDLE_EINTR(mkstemp(buffer));
 439 }
 440
 441 bool CreateTemporaryFile(FilePath* path) {
 442   base::ThreadRestrictions::AssertIOAllowed();  // For call to close().
 443   FilePath directory;
 444   if (!GetTempDir(&directory))
 445     return false;
 446   int fd = CreateAndOpenFdForTemporaryFile(directory, path);
 447   if (fd < 0)
 448     return false;
 449   ignore_result(HANDLE_EINTR(close(fd)));
 450   return true;
 451 }
 452
 453 FILE* CreateAndOpenTemporaryShmemFile(FilePath* path, bool executable) {
 454   FilePath directory;
 455   if (!GetShmemTempDir(&directory, executable))
 456     return NULL;
 457
 458   return CreateAndOpenTemporaryFileInDir(directory, path);
 459 }
 460
 461 FILE* CreateAndOpenTemporaryFileInDir(const FilePath& dir, FilePath* path) {
 462   int fd = CreateAndOpenFdForTemporaryFile(dir, path);
 463   if (fd < 0)
 464     return NULL;
 465
 466   FILE* file = fdopen(fd, "a+");
 467   if (!file)
 468     ignore_result(HANDLE_EINTR(close(fd)));
 469   return file;
 470 }
 471
 472 bool CreateTemporaryFileInDir(const FilePath& dir, FilePath* temp_file) {
 473   base::ThreadRestrictions::AssertIOAllowed();  // For call to close().
 474   int fd = CreateAndOpenFdForTemporaryFile(dir, temp_file);
 475   return ((fd >= 0) && !HANDLE_EINTR(close(fd)));
 476 }
 477
 478 static bool CreateTemporaryDirInDirImpl(const FilePath& base_dir,
 479                                         const FilePath::StringType& name_tmpl,
 480                                         FilePath* new_dir) {
 481   base::ThreadRestrictions::AssertIOAllowed();  // For call to mkdtemp().
 482   DCHECK(name_tmpl.find("XXXXXX") != FilePath::StringType::npos)
 483       << "Directory name template must contain \"XXXXXX\".";
 484
 485   FilePath sub_dir = base_dir.Append(name_tmpl);
 486   std::string sub_dir_string = sub_dir.value();
 487
 488   // this should be OK since mkdtemp just replaces characters in place
 489   char* buffer = const_cast<char*>(sub_dir_string.c_str());
 490   char* dtemp = mkdtemp(buffer);
 491   if (!dtemp) {
 492     DPLOG(ERROR) << "mkdtemp";
 493     return false;
 494   }
 495   *new_dir = FilePath(dtemp);
 496   return true;
 497 }
 498
 499 bool CreateTemporaryDirInDir(const FilePath& base_dir,
 500                              const FilePath::StringType& prefix,
 501                              FilePath* new_dir) {
 502   FilePath::StringType mkdtemp_template = prefix;
 503   mkdtemp_template.append(FILE_PATH_LITERAL("XXXXXX"));
 504   return CreateTemporaryDirInDirImpl(base_dir, mkdtemp_template, new_dir);
 505 }
 506
 507 bool CreateNewTempDirectory(const FilePath::StringType& prefix,
 508                             FilePath* new_temp_path) {
 509   FilePath tmpdir;
 510   if (!GetTempDir(&tmpdir))
 511     return false;
 512
 513   return CreateTemporaryDirInDirImpl(tmpdir, TempFileName(), new_temp_path);
 514 }
 515
 516 bool CreateDirectory(const FilePath& full_path) {
 517   base::ThreadRestrictions::AssertIOAllowed();  // For call to mkdir().
 518   std::vector<FilePath> subpaths;
 519
 520   // Collect a list of all parent directories.
 521   FilePath last_path = full_path;
 522   subpaths.push_back(full_path);
 523   for (FilePath path = full_path.DirName();
 524        path.value() != last_path.value(); path = path.DirName()) {
 525     subpaths.push_back(path);
 526     last_path = path;
 527   }
 528
 529   // Iterate through the parents and create the missing ones.
 530   for (std::vector<FilePath>::reverse_iterator i = subpaths.rbegin();
 531        i != subpaths.rend(); ++i) {
 532     if (DirectoryExists(*i))
 533       continue;
 534     if (mkdir(i->value().c_str(), 0700) == 0)
 535       continue;
 536     // Mkdir failed, but it might have failed with EEXIST, or some other error
 537     // due to the the directory appearing out of thin air. This can occur if
 538     // two processes are trying to create the same file system tree at the same
 539     // time. Check to see if it exists and make sure it is a directory.
 540     if (!DirectoryExists(*i))
 541       return false;
 542   }
 543   return true;
 544 }
 545
 546 base::FilePath MakeUniqueDirectory(const base::FilePath& path) {
 547   const int kMaxAttempts = 20;
 548   for (int attempts = 0; attempts < kMaxAttempts; attempts++) {
 549     int uniquifier =
 550         GetUniquePathNumber(path, base::FilePath::StringType());
 551     if (uniquifier < 0)
 552       break;
 553     base::FilePath test_path = (uniquifier == 0) ? path :
 554         path.InsertBeforeExtensionASCII(
 555             base::StringPrintf(" (%d)", uniquifier));
 556     if (mkdir(test_path.value().c_str(), 0777) == 0)
 557       return test_path;
 558     else if (errno != EEXIST)
 559       break;
 560   }
 561   return base::FilePath();
 562 }
 563
 564 // TODO(rkc): Refactor GetFileInfo and FileEnumerator to handle symlinks
 565 // correctly. http://code.google.com/p/chromium-os/issues/detail?id=15948
 566 bool IsLink(const FilePath& file_path) {
 567   stat_wrapper_t st;
 568   // If we can't lstat the file, it's safe to assume that the file won't at
 569   // least be a 'followable' link.
 570   if (CallLstat(file_path.value().c_str(), &st) != 0)
 571     return false;
 572
 573   if (S_ISLNK(st.st_mode))
 574     return true;
 575   else
 576     return false;
 577 }
 578
 579 bool GetFileInfo(const FilePath& file_path, base::PlatformFileInfo* results) {
 580   stat_wrapper_t file_info;
 581   if (CallStat(file_path.value().c_str(), &file_info) != 0)
 582     return false;
 583   results->is_directory = S_ISDIR(file_info.st_mode);
 584   results->size = file_info.st_size;
 585   results->last_modified = base::Time::FromTimeT(file_info.st_mtime);
 586   results->last_accessed = base::Time::FromTimeT(file_info.st_atime);
 587   results->creation_time = base::Time::FromTimeT(file_info.st_ctime);
 588   return true;
 589 }
 590
 591 bool GetInode(const FilePath& path, ino_t* inode) {
 592   base::ThreadRestrictions::AssertIOAllowed();  // For call to stat().
 593   struct stat buffer;
 594   int result = stat(path.value().c_str(), &buffer);
 595   if (result < 0)
 596     return false;
 597
 598   *inode = buffer.st_ino;
 599   return true;
 600 }
 601
 602 FILE* OpenFile(const std::string& filename, const char* mode) {
 603   return OpenFile(FilePath(filename), mode);
 604 }
 605
 606 FILE* OpenFile(const FilePath& filename, const char* mode) {
 607   base::ThreadRestrictions::AssertIOAllowed();
 608   FILE* result = NULL;
 609   do {
 610     result = fopen(filename.value().c_str(), mode);
 611   } while (!result && errno == EINTR);
 612   return result;
 613 }
 614
 615 int ReadFile(const FilePath& filename, char* data, int size) {
 616   base::ThreadRestrictions::AssertIOAllowed();
 617   int fd = HANDLE_EINTR(open(filename.value().c_str(), O_RDONLY));
 618   if (fd < 0)
 619     return -1;
 620
 621   ssize_t bytes_read = HANDLE_EINTR(read(fd, data, size));
 622   if (int ret = HANDLE_EINTR(close(fd)) < 0)
 623     return ret;
 624   return bytes_read;
 625 }
 626
 627 int WriteFile(const FilePath& filename, const char* data, int size) {
 628   base::ThreadRestrictions::AssertIOAllowed();
 629   int fd = HANDLE_EINTR(creat(filename.value().c_str(), 0666));
 630   if (fd < 0)
 631     return -1;
 632
 633   int bytes_written = WriteFileDescriptor(fd, data, size);
 634   if (int ret = HANDLE_EINTR(close(fd)) < 0)
 635     return ret;
 636   return bytes_written;
 637 }
 638
 639 int WriteFileDescriptor(const int fd, const char* data, int size) {
 640   // Allow for partial writes.
 641   ssize_t bytes_written_total = 0;
 642   for (ssize_t bytes_written_partial = 0; bytes_written_total < size;
 643        bytes_written_total += bytes_written_partial) {
 644     bytes_written_partial =
 645         HANDLE_EINTR(write(fd, data + bytes_written_total,
 646                            size - bytes_written_total));
 647     if (bytes_written_partial < 0)
 648       return -1;
 649   }
 650
 651   return bytes_written_total;
 652 }
 653
 654 int AppendToFile(const FilePath& filename, const char* data, int size) {
 655   base::ThreadRestrictions::AssertIOAllowed();
 656   int fd = HANDLE_EINTR(open(filename.value().c_str(), O_WRONLY | O_APPEND));
 657   if (fd < 0)
 658     return -1;
 659
 660   int bytes_written = WriteFileDescriptor(fd, data, size);
 661   if (int ret = HANDLE_EINTR(close(fd)) < 0)
 662     return ret;
 663   return bytes_written;
 664 }
 665
 666 // Gets the current working directory for the process.
 667 bool GetCurrentDirectory(FilePath* dir) {
 668   // getcwd can return ENOENT, which implies it checks against the disk.
 669   base::ThreadRestrictions::AssertIOAllowed();
 670
 671   char system_buffer[PATH_MAX] = "";
 672   if (!getcwd(system_buffer, sizeof(system_buffer))) {
 673     NOTREACHED();
 674     return false;
 675   }
 676   *dir = FilePath(system_buffer);
 677   return true;
 678 }
 679
 680 // Sets the current working directory for the process.
 681 bool SetCurrentDirectory(const FilePath& path) {
 682   base::ThreadRestrictions::AssertIOAllowed();
 683   int ret = chdir(path.value().c_str());
 684   return !ret;
 685 }
 686
 687 ///////////////////////////////////////////////
 688 // FileEnumerator
 689
 690 FileEnumerator::FileEnumerator(const FilePath& root_path,
 691                                bool recursive,
 692                                int file_type)
 693     : current_directory_entry_(0),
 694       root_path_(root_path),
 695       recursive_(recursive),
 696       file_type_(file_type) {
 697   // INCLUDE_DOT_DOT must not be specified if recursive.
 698   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 699   pending_paths_.push(root_path);
 700 }
 701
 702 FileEnumerator::FileEnumerator(const FilePath& root_path,
 703                                bool recursive,
 704                                int file_type,
 705                                const FilePath::StringType& pattern)
 706     : current_directory_entry_(0),
 707       root_path_(root_path),
 708       recursive_(recursive),
 709       file_type_(file_type),
 710       pattern_(root_path.Append(pattern).value()) {
 711   // INCLUDE_DOT_DOT must not be specified if recursive.
 712   DCHECK(!(recursive && (INCLUDE_DOT_DOT & file_type_)));
 713   // The Windows version of this code appends the pattern to the root_path,
 714   // potentially only matching against items in the top-most directory.
 715   // Do the same here.
 716   if (pattern.empty())
 717     pattern_ = FilePath::StringType();
 718   pending_paths_.push(root_path);
 719 }
 720
 721 FileEnumerator::~FileEnumerator() {
 722 }
 723
 724 FilePath FileEnumerator::Next() {
 725   ++current_directory_entry_;
 726
 727   // While we've exhausted the entries in the current directory, do the next
 728   while (current_directory_entry_ >= directory_entries_.size()) {
 729     if (pending_paths_.empty())
 730       return FilePath();
 731
 732     root_path_ = pending_paths_.top();
 733     root_path_ = root_path_.StripTrailingSeparators();
 734     pending_paths_.pop();
 735
 736     std::vector<DirectoryEntryInfo> entries;
 737     if (!ReadDirectory(&entries, root_path_, file_type_ & SHOW_SYM_LINKS))
 738       continue;
 739
 740     directory_entries_.clear();
 741     current_directory_entry_ = 0;
 742     for (std::vector<DirectoryEntryInfo>::const_iterator
 743         i = entries.begin(); i != entries.end(); ++i) {
 744       FilePath full_path = root_path_.Append(i->filename);
 745       if (ShouldSkip(full_path))
 746         continue;
 747
 748       if (pattern_.size() &&
 749           fnmatch(pattern_.c_str(), full_path.value().c_str(), FNM_NOESCAPE))
 750         continue;
 751
 752       if (recursive_ && S_ISDIR(i->stat.st_mode))
 753         pending_paths_.push(full_path);
 754
 755       if ((S_ISDIR(i->stat.st_mode) && (file_type_ & DIRECTORIES)) ||
 756           (!S_ISDIR(i->stat.st_mode) && (file_type_ & FILES)))
 757         directory_entries_.push_back(*i);
 758     }
 759   }
 760
 761   return root_path_.Append(directory_entries_[current_directory_entry_
 762       ].filename);
 763 }
 764
 765 void FileEnumerator::GetFindInfo(FindInfo* info) {
 766   DCHECK(info);
 767
 768   if (current_directory_entry_ >= directory_entries_.size())
 769     return;
 770
 771   DirectoryEntryInfo* cur_entry = &directory_entries_[current_directory_entry_];
 772   memcpy(&(info->stat), &(cur_entry->stat), sizeof(info->stat));
 773   info->filename.assign(cur_entry->filename.value());
 774 }
 775
 776 // static
 777 bool FileEnumerator::IsDirectory(const FindInfo& info) {
 778   return S_ISDIR(info.stat.st_mode);
 779 }
 780
 781 // static
 782 FilePath FileEnumerator::GetFilename(const FindInfo& find_info) {
 783   return FilePath(find_info.filename);
 784 }
 785
 786 // static
 787 int64 FileEnumerator::GetFilesize(const FindInfo& find_info) {
 788   return find_info.stat.st_size;
 789 }
 790
 791 // static
 792 base::Time FileEnumerator::GetLastModifiedTime(const FindInfo& find_info) {
 793   return base::Time::FromTimeT(find_info.stat.st_mtime);
 794 }
 795
 796 bool FileEnumerator::ReadDirectory(std::vector<DirectoryEntryInfo>* entries,
 797                                    const FilePath& source, bool show_links) {
 798   base::ThreadRestrictions::AssertIOAllowed();
 799   DIR* dir = opendir(source.value().c_str());
 800   if (!dir)
 801     return false;
 802
 803 #if !defined(OS_LINUX) && !defined(OS_MACOSX) && !defined(OS_BSD) && \
 804     !defined(OS_SOLARIS) && !defined(OS_ANDROID)
 805   #error Port warning: depending on the definition of struct dirent, \
 806          additional space for pathname may be needed
 807 #endif
 808
 809   struct dirent dent_buf;
 810   struct dirent* dent;
 811   while (readdir_r(dir, &dent_buf, &dent) == 0 && dent) {
 812     DirectoryEntryInfo info;
 813     info.filename = FilePath(dent->d_name);
 814
 815     FilePath full_name = source.Append(dent->d_name);
 816     int ret;
 817     if (show_links)
 818       ret = lstat(full_name.value().c_str(), &info.stat);
 819     else
 820       ret = stat(full_name.value().c_str(), &info.stat);
 821     if (ret < 0) {
 822       // Print the stat() error message unless it was ENOENT and we're
 823       // following symlinks.
 824       if (!(errno == ENOENT && !show_links)) {
 825         DPLOG(ERROR) << "Couldn't stat "
 826                      << source.Append(dent->d_name).value();
 827       }
 828       memset(&info.stat, 0, sizeof(info.stat));
 829     }
 830     entries->push_back(info);
 831   }
 832
 833   closedir(dir);
 834   return true;
 835 }
 836
 837 bool NormalizeFilePath(const FilePath& path, FilePath* normalized_path) {
 838   FilePath real_path_result;
 839   if (!RealPath(path, &real_path_result))
 840     return false;
 841
 842   // To be consistant with windows, fail if |real_path_result| is a
 843   // directory.
 844   stat_wrapper_t file_info;
 845   if (CallStat(real_path_result.value().c_str(), &file_info) != 0 ||
 846       S_ISDIR(file_info.st_mode))
 847     return false;
 848
 849   *normalized_path = real_path_result;
 850   return true;
 851 }
 852
 853 #if !defined(OS_MACOSX)
 854 bool GetTempDir(FilePath* path) {
 855   const char* tmp = getenv("TMPDIR");
 856   if (tmp)
 857     *path = FilePath(tmp);
 858   else
 859 #if defined(OS_ANDROID)
 860     return PathService::Get(base::DIR_CACHE, path);
 861 #else
 862     *path = FilePath("/tmp");
 863 #endif
 864   return true;
 865 }
 866
 867 #if !defined(OS_ANDROID)
 868
 869 #if defined(OS_LINUX)
 870 // Determine if /dev/shm files can be mapped and then mprotect'd PROT_EXEC.
 871 // This depends on the mount options used for /dev/shm, which vary among
 872 // different Linux distributions and possibly local configuration.  It also
 873 // depends on details of kernel--ChromeOS uses the noexec option for /dev/shm
 874 // but its kernel allows mprotect with PROT_EXEC anyway.
 875
 876 namespace {
 877
 878 bool DetermineDevShmExecutable() {
 879   bool result = false;
 880   FilePath path;
 881   int fd = CreateAndOpenFdForTemporaryFile(FilePath("/dev/shm"), &path);
 882   if (fd >= 0) {
 883     ScopedFD shm_fd_closer(&fd);
 884     Delete(path, false);
 885     long sysconf_result = sysconf(_SC_PAGESIZE);
 886     CHECK_GE(sysconf_result, 0);
 887     size_t pagesize = static_cast<size_t>(sysconf_result);
 888     CHECK_GE(sizeof(pagesize), sizeof(sysconf_result));
 889     void *mapping = mmap(NULL, pagesize, PROT_READ, MAP_SHARED, fd, 0);
 890     if (mapping != MAP_FAILED) {
 891       if (mprotect(mapping, pagesize, PROT_READ | PROT_EXEC) == 0)
 892         result = true;
 893       munmap(mapping, pagesize);
 894     }
 895   }
 896   return result;
 897 }
 898
 899 };  // namespace
 900 #endif  // defined(OS_LINUX)
 901
 902 bool GetShmemTempDir(FilePath* path, bool executable) {
 903 #if defined(OS_LINUX)
 904   bool use_dev_shm = true;
 905   if (executable) {
 906     static const bool s_dev_shm_executable = DetermineDevShmExecutable();
 907     use_dev_shm = s_dev_shm_executable;
 908   }
 909   if (use_dev_shm) {
 910     *path = FilePath("/dev/shm");
 911     return true;
 912   }
 913 #endif
 914   return GetTempDir(path);
 915 }
 916 #endif  // !defined(OS_ANDROID)
 917
 918 FilePath GetHomeDir() {
 919 #if defined(OS_CHROMEOS)
 920   if (base::chromeos::IsRunningOnChromeOS())
 921     return FilePath("/home/chronos/user");
 922 #endif
 923
 924   const char* home_dir = getenv("HOME");
 925   if (home_dir && home_dir[0])
 926     return FilePath(home_dir);
 927
 928 #if defined(OS_ANDROID)
 929   DLOG(WARNING) << "OS_ANDROID: Home directory lookup not yet implemented.";
 930 #else
 931   // g_get_home_dir calls getpwent, which can fall through to LDAP calls.
 932   base::ThreadRestrictions::AssertIOAllowed();
 933
 934   home_dir = g_get_home_dir();
 935   if (home_dir && home_dir[0])
 936     return FilePath(home_dir);
 937 #endif
 938
 939   FilePath rv;
 940   if (file_util::GetTempDir(&rv))
 941     return rv;
 942
 943   // Last resort.
 944   return FilePath("/tmp");
 945 }
 946
 947 bool CopyFileUnsafe(const FilePath& from_path, const FilePath& to_path) {
 948   base::ThreadRestrictions::AssertIOAllowed();
 949   int infile = HANDLE_EINTR(open(from_path.value().c_str(), O_RDONLY));
 950   if (infile < 0)
 951     return false;
 952
 953   int outfile = HANDLE_EINTR(creat(to_path.value().c_str(), 0666));
 954   if (outfile < 0) {
 955     ignore_result(HANDLE_EINTR(close(infile)));
 956     return false;
 957   }
 958
 959   const size_t kBufferSize = 32768;
 960   std::vector<char> buffer(kBufferSize);
 961   bool result = true;
 962
 963   while (result) {
 964     ssize_t bytes_read = HANDLE_EINTR(read(infile, &buffer[0], buffer.size()));
 965     if (bytes_read < 0) {
 966       result = false;
 967       break;
 968     }
 969     if (bytes_read == 0)
 970       break;
 971     // Allow for partial writes
 972     ssize_t bytes_written_per_read = 0;
 973     do {
 974       ssize_t bytes_written_partial = HANDLE_EINTR(write(
 975           outfile,
 976           &buffer[bytes_written_per_read],
 977           bytes_read - bytes_written_per_read));
 978       if (bytes_written_partial < 0) {
 979         result = false;
 980         break;
 981       }
 982       bytes_written_per_read += bytes_written_partial;
 983     } while (bytes_written_per_read < bytes_read);
 984   }
 985
 986   if (HANDLE_EINTR(close(infile)) < 0)
 987     result = false;
 988   if (HANDLE_EINTR(close(outfile)) < 0)
 989     result = false;
 990
 991   return result;
 992 }
 993 #endif  // !defined(OS_MACOSX)
 994
 995 bool VerifyPathControlledByUser(const FilePath& base,
 996                                 const FilePath& path,
 997                                 uid_t owner_uid,
 998                                 const std::set<gid_t>& group_gids) {
 999   if (base != path && !base.IsParent(path)) {
1000      DLOG(ERROR) << "|base| must be a subdirectory of |path|.  base = \""
1001                  << base.value() << "\", path = \"" << path.value() << "\"";
1002      return false;
1003   }
1004
1005   std::vector<FilePath::StringType> base_components;
1006   std::vector<FilePath::StringType> path_components;
1007
1008   base.GetComponents(&base_components);
1009   path.GetComponents(&path_components);
1010
1011   std::vector<FilePath::StringType>::const_iterator ib, ip;
1012   for (ib = base_components.begin(), ip = path_components.begin();
1013        ib != base_components.end(); ++ib, ++ip) {
1014     // |base| must be a subpath of |path|, so all components should match.
1015     // If these CHECKs fail, look at the test that base is a parent of
1016     // path at the top of this function.
1017     DCHECK(ip != path_components.end());
1018     DCHECK(*ip == *ib);
1019   }
1020
1021   FilePath current_path = base;
1022   if (!VerifySpecificPathControlledByUser(current_path, owner_uid, group_gids))
1023     return false;
1024
1025   for (; ip != path_components.end(); ++ip) {
1026     current_path = current_path.Append(*ip);
1027     if (!VerifySpecificPathControlledByUser(
1028             current_path, owner_uid, group_gids))
1029       return false;
1030   }
1031   return true;
1032 }
1033
1034 #if defined(OS_MACOSX) && !defined(OS_IOS)
1035 bool VerifyPathControlledByAdmin(const FilePath& path) {
1036   const unsigned kRootUid = 0;
1037   const FilePath kFileSystemRoot("/");
1038
1039   // The name of the administrator group on mac os.
1040   const char* const kAdminGroupNames[] = {
1041     "admin",
1042     "wheel"
1043   };
1044
1045   // Reading the groups database may touch the file system.
1046   base::ThreadRestrictions::AssertIOAllowed();
1047
1048   std::set<gid_t> allowed_group_ids;
1049   for (int i = 0, ie = arraysize(kAdminGroupNames); i < ie; ++i) {
1050     struct group *group_record = getgrnam(kAdminGroupNames[i]);
1051     if (!group_record) {
1052       DPLOG(ERROR) << "Could not get the group ID of group \""
1053                    << kAdminGroupNames[i] << "\".";
1054       continue;
1055     }
1056
1057     allowed_group_ids.insert(group_record->gr_gid);
1058   }
1059
1060   return VerifyPathControlledByUser(
1061       kFileSystemRoot, path, kRootUid, allowed_group_ids);
1062 }
1063 #endif  // defined(OS_MACOSX) && !defined(OS_IOS)
1064
1065 int GetMaximumPathComponentLength(const FilePath& path) {
1066   base::ThreadRestrictions::AssertIOAllowed();
1067   return pathconf(path.value().c_str(), _PC_NAME_MAX);
1068 }
1069
1070 }  // namespace file_util