base/files/file_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/files/file.h"
   6
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <sys/stat.h>
  10 #include <unistd.h>
  11
  12 #include "base/files/file_path.h"
  13 #include "base/logging.h"
  14 #include "base/metrics/sparse_histogram.h"
  15 #include "base/posix/eintr_wrapper.h"
  16 #include "base/strings/utf_string_conversions.h"
  17 #include "base/threading/thread_restrictions.h"
  18
  19 #if defined(OS_ANDROID)
  20 #include "base/os_compat_android.h"
  21 #endif
  22
  23 namespace base {
  24
  25 // Make sure our Whence mappings match the system headers.
  26 COMPILE_ASSERT(File::FROM_BEGIN   == SEEK_SET &&
  27                File::FROM_CURRENT == SEEK_CUR &&
  28                File::FROM_END     == SEEK_END, whence_matches_system);
  29
  30 namespace {
  31
  32 #if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)
  33 static int CallFstat(int fd, stat_wrapper_t *sb) {
  34   base::ThreadRestrictions::AssertIOAllowed();
  35   return fstat(fd, sb);
  36 }
  37 #else
  38 static int CallFstat(int fd, stat_wrapper_t *sb) {
  39   base::ThreadRestrictions::AssertIOAllowed();
  40   return fstat64(fd, sb);
  41 }
  42 #endif
  43
  44 // NaCl doesn't provide the following system calls, so either simulate them or
  45 // wrap them in order to minimize the number of #ifdef's in this file.
  46 #if !defined(OS_NACL)
  47 static bool IsOpenAppend(PlatformFile file) {
  48   return (fcntl(file, F_GETFL) & O_APPEND) != 0;
  49 }
  50
  51 static int CallFtruncate(PlatformFile file, int64 length) {
  52   return HANDLE_EINTR(ftruncate(file, length));
  53 }
  54
  55 static int CallFsync(PlatformFile file) {
  56   return HANDLE_EINTR(fsync(file));
  57 }
  58
  59 static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
  60 #ifdef __USE_XOPEN2K8
  61   // futimens should be available, but futimes might not be
  62   // http://pubs.opengroup.org/onlinepubs/9699919799/
  63
  64   timespec ts_times[2];
  65   ts_times[0].tv_sec  = times[0].tv_sec;
  66   ts_times[0].tv_nsec = times[0].tv_usec * 1000;
  67   ts_times[1].tv_sec  = times[1].tv_sec;
  68   ts_times[1].tv_nsec = times[1].tv_usec * 1000;
  69
  70   return futimens(file, ts_times);
  71 #else
  72   return futimes(file, times);
  73 #endif
  74 }
  75
  76 static File::Error CallFctnlFlock(PlatformFile file, bool do_lock) {
  77   struct flock lock;
  78   lock.l_type = F_WRLCK;
  79   lock.l_whence = SEEK_SET;
  80   lock.l_start = 0;
  81   lock.l_len = 0;  // Lock entire file.
  82   if (HANDLE_EINTR(fcntl(file, do_lock ? F_SETLK : F_UNLCK, &lock)) == -1)
  83     return File::OSErrorToFileError(errno);
  84   return File::FILE_OK;
  85 }
  86 #else  // defined(OS_NACL)
  87
  88 static bool IsOpenAppend(PlatformFile file) {
  89   // NaCl doesn't implement fcntl. Since NaCl's write conforms to the POSIX
  90   // standard and always appends if the file is opened with O_APPEND, just
  91   // return false here.
  92   return false;
  93 }
  94
  95 static int CallFtruncate(PlatformFile file, int64 length) {
  96   NOTIMPLEMENTED();  // NaCl doesn't implement ftruncate.
  97   return 0;
  98 }
  99
 100 static int CallFsync(PlatformFile file) {
 101   NOTIMPLEMENTED();  // NaCl doesn't implement fsync.
 102   return 0;
 103 }
 104
 105 static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
 106   NOTIMPLEMENTED();  // NaCl doesn't implement futimes.
 107   return 0;
 108 }
 109
 110 static File::Error CallFctnlFlock(PlatformFile file, bool do_lock) {
 111   NOTIMPLEMENTED();  // NaCl doesn't implement flock struct.
 112   return File::FILE_ERROR_INVALID_OPERATION;
 113 }
 114 #endif  // defined(OS_NACL)
 115
 116 }  // namespace
 117
 118 void File::Info::FromStat(const stat_wrapper_t& stat_info) {
 119   is_directory = S_ISDIR(stat_info.st_mode);
 120   is_symbolic_link = S_ISLNK(stat_info.st_mode);
 121   size = stat_info.st_size;
 122
 123 #if defined(OS_LINUX)
 124   time_t last_modified_sec = stat_info.st_mtim.tv_sec;
 125   int64 last_modified_nsec = stat_info.st_mtim.tv_nsec;
 126   time_t last_accessed_sec = stat_info.st_atim.tv_sec;
 127   int64 last_accessed_nsec = stat_info.st_atim.tv_nsec;
 128   time_t creation_time_sec = stat_info.st_ctim.tv_sec;
 129   int64 creation_time_nsec = stat_info.st_ctim.tv_nsec;
 130 #elif defined(OS_ANDROID)
 131   time_t last_modified_sec = stat_info.st_mtime;
 132   int64 last_modified_nsec = stat_info.st_mtime_nsec;
 133   time_t last_accessed_sec = stat_info.st_atime;
 134   int64 last_accessed_nsec = stat_info.st_atime_nsec;
 135   time_t creation_time_sec = stat_info.st_ctime;
 136   int64 creation_time_nsec = stat_info.st_ctime_nsec;
 137 #elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)
 138   time_t last_modified_sec = stat_info.st_mtimespec.tv_sec;
 139   int64 last_modified_nsec = stat_info.st_mtimespec.tv_nsec;
 140   time_t last_accessed_sec = stat_info.st_atimespec.tv_sec;
 141   int64 last_accessed_nsec = stat_info.st_atimespec.tv_nsec;
 142   time_t creation_time_sec = stat_info.st_ctimespec.tv_sec;
 143   int64 creation_time_nsec = stat_info.st_ctimespec.tv_nsec;
 144 #else
 145   time_t last_modified_sec = stat_info.st_mtime;
 146   int64 last_modified_nsec = 0;
 147   time_t last_accessed_sec = stat_info.st_atime;
 148   int64 last_accessed_nsec = 0;
 149   time_t creation_time_sec = stat_info.st_ctime;
 150   int64 creation_time_nsec = 0;
 151 #endif
 152
 153   last_modified =
 154       Time::FromTimeT(last_modified_sec) +
 155       TimeDelta::FromMicroseconds(last_modified_nsec /
 156                                   Time::kNanosecondsPerMicrosecond);
 157
 158   last_accessed =
 159       Time::FromTimeT(last_accessed_sec) +
 160       TimeDelta::FromMicroseconds(last_accessed_nsec /
 161                                   Time::kNanosecondsPerMicrosecond);
 162
 163   creation_time =
 164       Time::FromTimeT(creation_time_sec) +
 165       TimeDelta::FromMicroseconds(creation_time_nsec /
 166                                   Time::kNanosecondsPerMicrosecond);
 167 }
 168
 169 // NaCl doesn't implement system calls to open files directly.
 170 #if !defined(OS_NACL)
 171 // TODO(erikkay): does it make sense to support FLAG_EXCLUSIVE_* here?
 172 void File::InitializeUnsafe(const FilePath& name, uint32 flags) {
 173   base::ThreadRestrictions::AssertIOAllowed();
 174   DCHECK(!IsValid());
 175
 176   int open_flags = 0;
 177   if (flags & FLAG_CREATE)
 178     open_flags = O_CREAT | O_EXCL;
 179
 180   created_ = false;
 181
 182   if (flags & FLAG_CREATE_ALWAYS) {
 183     DCHECK(!open_flags);
 184     DCHECK(flags & FLAG_WRITE);
 185     open_flags = O_CREAT | O_TRUNC;
 186   }
 187
 188   if (flags & FLAG_OPEN_TRUNCATED) {
 189     DCHECK(!open_flags);
 190     DCHECK(flags & FLAG_WRITE);
 191     open_flags = O_TRUNC;
 192   }
 193
 194   if (!open_flags && !(flags & FLAG_OPEN) && !(flags & FLAG_OPEN_ALWAYS)) {
 195     NOTREACHED();
 196     errno = EOPNOTSUPP;
 197     error_details_ = FILE_ERROR_FAILED;
 198     return;
 199   }
 200
 201   if (flags & FLAG_WRITE && flags & FLAG_READ) {
 202     open_flags |= O_RDWR;
 203   } else if (flags & FLAG_WRITE) {
 204     open_flags |= O_WRONLY;
 205   } else if (!(flags & FLAG_READ) &&
 206              !(flags & FLAG_WRITE_ATTRIBUTES) &&
 207              !(flags & FLAG_APPEND) &&
 208              !(flags & FLAG_OPEN_ALWAYS)) {
 209     NOTREACHED();
 210   }
 211
 212   if (flags & FLAG_TERMINAL_DEVICE)
 213     open_flags |= O_NOCTTY | O_NDELAY;
 214
 215   if (flags & FLAG_APPEND && flags & FLAG_READ)
 216     open_flags |= O_APPEND | O_RDWR;
 217   else if (flags & FLAG_APPEND)
 218     open_flags |= O_APPEND | O_WRONLY;
 219
 220   COMPILE_ASSERT(O_RDONLY == 0, O_RDONLY_must_equal_zero);
 221
 222   int mode = S_IRUSR | S_IWUSR;
 223 #if defined(OS_CHROMEOS)
 224   mode |= S_IRGRP | S_IROTH;
 225 #endif
 226
 227   int descriptor = HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));
 228
 229   if (flags & FLAG_OPEN_ALWAYS) {
 230     if (descriptor < 0) {
 231       open_flags |= O_CREAT;
 232       if (flags & FLAG_EXCLUSIVE_READ || flags & FLAG_EXCLUSIVE_WRITE)
 233         open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW
 234
 235       descriptor = HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));
 236       if (descriptor >= 0)
 237         created_ = true;
 238     }
 239   }
 240
 241   if (descriptor < 0) {
 242     error_details_ = File::OSErrorToFileError(errno);
 243     return;
 244   }
 245
 246   if (flags & (FLAG_CREATE_ALWAYS | FLAG_CREATE))
 247     created_ = true;
 248
 249   if (flags & FLAG_DELETE_ON_CLOSE)
 250     unlink(name.value().c_str());
 251
 252   async_ = ((flags & FLAG_ASYNC) == FLAG_ASYNC);
 253   error_details_ = FILE_OK;
 254   file_.reset(descriptor);
 255 }
 256 #endif  // !defined(OS_NACL)
 257
 258 bool File::IsValid() const {
 259   return file_.is_valid();
 260 }
 261
 262 PlatformFile File::GetPlatformFile() const {
 263   return file_.get();
 264 }
 265
 266 PlatformFile File::TakePlatformFile() {
 267   return file_.release();
 268 }
 269
 270 void File::Close() {
 271   if (!IsValid())
 272     return;
 273
 274   base::ThreadRestrictions::AssertIOAllowed();
 275   file_.reset();
 276 }
 277
 278 int64 File::Seek(Whence whence, int64 offset) {
 279   base::ThreadRestrictions::AssertIOAllowed();
 280   DCHECK(IsValid());
 281
 282 #if defined(OS_ANDROID)
 283   COMPILE_ASSERT(sizeof(int64) == sizeof(off64_t), off64_t_64_bit);
 284   return lseek64(file_.get(), static_cast<off64_t>(offset),
 285                  static_cast<int>(whence));
 286 #else
 287   COMPILE_ASSERT(sizeof(int64) == sizeof(off_t), off_t_64_bit);
 288   return lseek(file_.get(), static_cast<off_t>(offset),
 289                static_cast<int>(whence));
 290 #endif
 291 }
 292
 293 int File::Read(int64 offset, char* data, int size) {
 294   base::ThreadRestrictions::AssertIOAllowed();
 295   DCHECK(IsValid());
 296   if (size < 0)
 297     return -1;
 298
 299   int bytes_read = 0;
 300   int rv;
 301   do {
 302     rv = HANDLE_EINTR(pread(file_.get(), data + bytes_read,
 303                             size - bytes_read, offset + bytes_read));
 304     if (rv <= 0)
 305       break;
 306
 307     bytes_read += rv;
 308   } while (bytes_read < size);
 309
 310   return bytes_read ? bytes_read : rv;
 311 }
 312
 313 int File::ReadAtCurrentPos(char* data, int size) {
 314   base::ThreadRestrictions::AssertIOAllowed();
 315   DCHECK(IsValid());
 316   if (size < 0)
 317     return -1;
 318
 319   int bytes_read = 0;
 320   int rv;
 321   do {
 322     rv = HANDLE_EINTR(read(file_.get(), data + bytes_read, size - bytes_read));
 323     if (rv <= 0)
 324       break;
 325
 326     bytes_read += rv;
 327   } while (bytes_read < size);
 328
 329   return bytes_read ? bytes_read : rv;
 330 }
 331
 332 int File::ReadNoBestEffort(int64 offset, char* data, int size) {
 333   base::ThreadRestrictions::AssertIOAllowed();
 334   DCHECK(IsValid());
 335
 336   return HANDLE_EINTR(pread(file_.get(), data, size, offset));
 337 }
 338
 339 int File::ReadAtCurrentPosNoBestEffort(char* data, int size) {
 340   base::ThreadRestrictions::AssertIOAllowed();
 341   DCHECK(IsValid());
 342   if (size < 0)
 343     return -1;
 344
 345   return HANDLE_EINTR(read(file_.get(), data, size));
 346 }
 347
 348 int File::Write(int64 offset, const char* data, int size) {
 349   base::ThreadRestrictions::AssertIOAllowed();
 350
 351   if (IsOpenAppend(file_.get()))
 352     return WriteAtCurrentPos(data, size);
 353
 354   DCHECK(IsValid());
 355   if (size < 0)
 356     return -1;
 357
 358   int bytes_written = 0;
 359   int rv;
 360   do {
 361     rv = HANDLE_EINTR(pwrite(file_.get(), data + bytes_written,
 362                              size - bytes_written, offset + bytes_written));
 363     if (rv <= 0)
 364       break;
 365
 366     bytes_written += rv;
 367   } while (bytes_written < size);
 368
 369   return bytes_written ? bytes_written : rv;
 370 }
 371
 372 int File::WriteAtCurrentPos(const char* data, int size) {
 373   base::ThreadRestrictions::AssertIOAllowed();
 374   DCHECK(IsValid());
 375   if (size < 0)
 376     return -1;
 377
 378   int bytes_written = 0;
 379   int rv;
 380   do {
 381     rv = HANDLE_EINTR(write(file_.get(), data + bytes_written,
 382                             size - bytes_written));
 383     if (rv <= 0)
 384       break;
 385
 386     bytes_written += rv;
 387   } while (bytes_written < size);
 388
 389   return bytes_written ? bytes_written : rv;
 390 }
 391
 392 int File::WriteAtCurrentPosNoBestEffort(const char* data, int size) {
 393   base::ThreadRestrictions::AssertIOAllowed();
 394   DCHECK(IsValid());
 395   if (size < 0)
 396     return -1;
 397
 398   return HANDLE_EINTR(write(file_.get(), data, size));
 399 }
 400
 401 int64 File::GetLength() {
 402   DCHECK(IsValid());
 403
 404   stat_wrapper_t file_info;
 405   if (CallFstat(file_.get(), &file_info))
 406     return false;
 407
 408   return file_info.st_size;
 409 }
 410
 411 bool File::SetLength(int64 length) {
 412   base::ThreadRestrictions::AssertIOAllowed();
 413   DCHECK(IsValid());
 414   return !CallFtruncate(file_.get(), length);
 415 }
 416
 417 bool File::Flush() {
 418   base::ThreadRestrictions::AssertIOAllowed();
 419   DCHECK(IsValid());
 420   return !CallFsync(file_.get());
 421 }
 422
 423 bool File::SetTimes(Time last_access_time, Time last_modified_time) {
 424   base::ThreadRestrictions::AssertIOAllowed();
 425   DCHECK(IsValid());
 426
 427   timeval times[2];
 428   times[0] = last_access_time.ToTimeVal();
 429   times[1] = last_modified_time.ToTimeVal();
 430
 431   return !CallFutimes(file_.get(), times);
 432 }
 433
 434 bool File::GetInfo(Info* info) {
 435   DCHECK(IsValid());
 436
 437   stat_wrapper_t file_info;
 438   if (CallFstat(file_.get(), &file_info))
 439     return false;
 440
 441   info->FromStat(file_info);
 442   return true;
 443 }
 444
 445 File::Error File::Lock() {
 446   return CallFctnlFlock(file_.get(), true);
 447 }
 448
 449 File::Error File::Unlock() {
 450   return CallFctnlFlock(file_.get(), false);
 451 }
 452
 453 // Static.
 454 File::Error File::OSErrorToFileError(int saved_errno) {
 455   switch (saved_errno) {
 456     case EACCES:
 457     case EISDIR:
 458     case EROFS:
 459     case EPERM:
 460       return FILE_ERROR_ACCESS_DENIED;
 461 #if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
 462     case ETXTBSY:
 463       return FILE_ERROR_IN_USE;
 464 #endif
 465     case EEXIST:
 466       return FILE_ERROR_EXISTS;
 467     case ENOENT:
 468       return FILE_ERROR_NOT_FOUND;
 469     case EMFILE:
 470       return FILE_ERROR_TOO_MANY_OPENED;
 471     case ENOMEM:
 472       return FILE_ERROR_NO_MEMORY;
 473     case ENOSPC:
 474       return FILE_ERROR_NO_SPACE;
 475     case ENOTDIR:
 476       return FILE_ERROR_NOT_A_DIRECTORY;
 477     default:
 478 #if !defined(OS_NACL)  // NaCl build has no metrics code.
 479       UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Posix",
 480                                   saved_errno);
 481 #endif
 482       return FILE_ERROR_FAILED;
 483   }
 484 }
 485
 486 void File::SetPlatformFile(PlatformFile file) {
 487   DCHECK(!file_.is_valid());
 488   file_.reset(file);
 489 }
 490
 491 }  // namespace base