base/platform_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/platform_file.h"
   6
   7 #include <fcntl.h>
   8 #include <errno.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(PLATFORM_FILE_FROM_BEGIN   == SEEK_SET &&
  27                PLATFORM_FILE_FROM_CURRENT == SEEK_CUR &&
  28                PLATFORM_FILE_FROM_END     == SEEK_END, whence_matches_system);
  29
  30 namespace {
  31
  32 #if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)
  33 typedef struct stat stat_wrapper_t;
  34 static int CallFstat(int fd, stat_wrapper_t *sb) {
  35   base::ThreadRestrictions::AssertIOAllowed();
  36   return fstat(fd, sb);
  37 }
  38 #else
  39 typedef struct stat64 stat_wrapper_t;
  40 static int CallFstat(int fd, stat_wrapper_t *sb) {
  41   base::ThreadRestrictions::AssertIOAllowed();
  42   return fstat64(fd, sb);
  43 }
  44 #endif
  45
  46 // NaCl doesn't provide the following system calls, so either simulate them or
  47 // wrap them in order to minimize the number of #ifdef's in this file.
  48 #if !defined(OS_NACL)
  49 static bool IsOpenAppend(PlatformFile file) {
  50   return (fcntl(file, F_GETFL) & O_APPEND) != 0;
  51 }
  52
  53 static int CallFtruncate(PlatformFile file, int64 length) {
  54   return HANDLE_EINTR(ftruncate(file, length));
  55 }
  56
  57 static int CallFsync(PlatformFile file) {
  58   return HANDLE_EINTR(fsync(file));
  59 }
  60
  61 static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
  62 #ifdef __USE_XOPEN2K8
  63   // futimens should be available, but futimes might not be
  64   // http://pubs.opengroup.org/onlinepubs/9699919799/
  65
  66   timespec ts_times[2];
  67   ts_times[0].tv_sec  = times[0].tv_sec;
  68   ts_times[0].tv_nsec = times[0].tv_usec * 1000;
  69   ts_times[1].tv_sec  = times[1].tv_sec;
  70   ts_times[1].tv_nsec = times[1].tv_usec * 1000;
  71
  72   return futimens(file, ts_times);
  73 #else
  74   return futimes(file, times);
  75 #endif
  76 }
  77
  78 static PlatformFileError CallFctnlFlock(PlatformFile file, bool do_lock) {
  79   struct flock lock;
  80   lock.l_type = F_WRLCK;
  81   lock.l_whence = SEEK_SET;
  82   lock.l_start = 0;
  83   lock.l_len = 0;  // Lock entire file.
  84   if (HANDLE_EINTR(fcntl(file, do_lock ? F_SETLK : F_UNLCK, &lock)) == -1)
  85     return ErrnoToPlatformFileError(errno);
  86   return PLATFORM_FILE_OK;
  87 }
  88 #else  // defined(OS_NACL)
  89
  90 static bool IsOpenAppend(PlatformFile file) {
  91   // NaCl doesn't implement fcntl. Since NaCl's write conforms to the POSIX
  92   // standard and always appends if the file is opened with O_APPEND, just
  93   // return false here.
  94   return false;
  95 }
  96
  97 static int CallFtruncate(PlatformFile file, int64 length) {
  98   NOTIMPLEMENTED();  // NaCl doesn't implement ftruncate.
  99   return 0;
 100 }
 101
 102 static int CallFsync(PlatformFile file) {
 103   NOTIMPLEMENTED();  // NaCl doesn't implement fsync.
 104   return 0;
 105 }
 106
 107 static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
 108   NOTIMPLEMENTED();  // NaCl doesn't implement futimes.
 109   return 0;
 110 }
 111
 112 static PlatformFileError CallFctnlFlock(PlatformFile file, bool do_lock) {
 113   NOTIMPLEMENTED();  // NaCl doesn't implement flock struct.
 114   return PLATFORM_FILE_ERROR_INVALID_OPERATION;
 115 }
 116 #endif  // defined(OS_NACL)
 117
 118 }  // namespace
 119
 120 // NaCl doesn't implement system calls to open files directly.
 121 #if !defined(OS_NACL)
 122 // TODO(erikkay): does it make sense to support PLATFORM_FILE_EXCLUSIVE_* here?
 123 PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
 124                                       int flags,
 125                                       bool* created,
 126                                       PlatformFileError* error) {
 127   base::ThreadRestrictions::AssertIOAllowed();
 128
 129   int open_flags = 0;
 130   if (flags & PLATFORM_FILE_CREATE)
 131     open_flags = O_CREAT | O_EXCL;
 132
 133   if (created)
 134     *created = false;
 135
 136   if (flags & PLATFORM_FILE_CREATE_ALWAYS) {
 137     DCHECK(!open_flags);
 138     open_flags = O_CREAT | O_TRUNC;
 139   }
 140
 141   if (flags & PLATFORM_FILE_OPEN_TRUNCATED) {
 142     DCHECK(!open_flags);
 143     DCHECK(flags & PLATFORM_FILE_WRITE);
 144     open_flags = O_TRUNC;
 145   }
 146
 147   if (!open_flags && !(flags & PLATFORM_FILE_OPEN) &&
 148       !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
 149     NOTREACHED();
 150     errno = EOPNOTSUPP;
 151     if (error)
 152       *error = PLATFORM_FILE_ERROR_FAILED;
 153     return kInvalidPlatformFileValue;
 154   }
 155
 156   if (flags & PLATFORM_FILE_WRITE && flags & PLATFORM_FILE_READ) {
 157     open_flags |= O_RDWR;
 158   } else if (flags & PLATFORM_FILE_WRITE) {
 159     open_flags |= O_WRONLY;
 160   } else if (!(flags & PLATFORM_FILE_READ) &&
 161              !(flags & PLATFORM_FILE_WRITE_ATTRIBUTES) &&
 162              !(flags & PLATFORM_FILE_APPEND) &&
 163              !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
 164     NOTREACHED();
 165   }
 166
 167   if (flags & PLATFORM_FILE_TERMINAL_DEVICE)
 168     open_flags |= O_NOCTTY | O_NDELAY;
 169
 170   if (flags & PLATFORM_FILE_APPEND && flags & PLATFORM_FILE_READ)
 171     open_flags |= O_APPEND | O_RDWR;
 172   else if (flags & PLATFORM_FILE_APPEND)
 173     open_flags |= O_APPEND | O_WRONLY;
 174
 175   COMPILE_ASSERT(O_RDONLY == 0, O_RDONLY_must_equal_zero);
 176
 177   int mode = S_IRUSR | S_IWUSR;
 178 #if defined(OS_CHROMEOS)
 179   mode |= S_IRGRP | S_IROTH;
 180 #endif
 181
 182   int descriptor =
 183       HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));
 184
 185   if (flags & PLATFORM_FILE_OPEN_ALWAYS) {
 186     if (descriptor < 0) {
 187       open_flags |= O_CREAT;
 188       if (flags & PLATFORM_FILE_EXCLUSIVE_READ ||
 189           flags & PLATFORM_FILE_EXCLUSIVE_WRITE) {
 190         open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW
 191       }
 192       descriptor = HANDLE_EINTR(
 193           open(name.value().c_str(), open_flags, mode));
 194       if (created && descriptor >= 0)
 195         *created = true;
 196     }
 197   }
 198
 199   if (created && (descriptor >= 0) &&
 200       (flags & (PLATFORM_FILE_CREATE_ALWAYS | PLATFORM_FILE_CREATE)))
 201     *created = true;
 202
 203   if ((descriptor >= 0) && (flags & PLATFORM_FILE_DELETE_ON_CLOSE)) {
 204     unlink(name.value().c_str());
 205   }
 206
 207   if (error) {
 208     if (descriptor >= 0)
 209       *error = PLATFORM_FILE_OK;
 210     else
 211       *error = ErrnoToPlatformFileError(errno);
 212   }
 213
 214   return descriptor;
 215 }
 216
 217 FILE* FdopenPlatformFile(PlatformFile file, const char* mode) {
 218   return fdopen(file, mode);
 219 }
 220 #endif  // !defined(OS_NACL)
 221
 222 bool ClosePlatformFile(PlatformFile file) {
 223   base::ThreadRestrictions::AssertIOAllowed();
 224   return !IGNORE_EINTR(close(file));
 225 }
 226
 227 int64 SeekPlatformFile(PlatformFile file,
 228                        PlatformFileWhence whence,
 229                        int64 offset) {
 230   base::ThreadRestrictions::AssertIOAllowed();
 231   if (file < 0 || offset < 0)
 232     return -1;
 233
 234   return lseek(file, static_cast<off_t>(offset), static_cast<int>(whence));
 235 }
 236
 237 int ReadPlatformFile(PlatformFile file, int64 offset, char* data, int size) {
 238   base::ThreadRestrictions::AssertIOAllowed();
 239   if (file < 0 || size < 0)
 240     return -1;
 241
 242   int bytes_read = 0;
 243   int rv;
 244   do {
 245     rv = HANDLE_EINTR(pread(file, data + bytes_read,
 246                             size - bytes_read, offset + bytes_read));
 247     if (rv <= 0)
 248       break;
 249
 250     bytes_read += rv;
 251   } while (bytes_read < size);
 252
 253   return bytes_read ? bytes_read : rv;
 254 }
 255
 256 int ReadPlatformFileAtCurrentPos(PlatformFile file, char* data, int size) {
 257   base::ThreadRestrictions::AssertIOAllowed();
 258   if (file < 0 || size < 0)
 259     return -1;
 260
 261   int bytes_read = 0;
 262   int rv;
 263   do {
 264     rv = HANDLE_EINTR(read(file, data, size));
 265     if (rv <= 0)
 266       break;
 267
 268     bytes_read += rv;
 269   } while (bytes_read < size);
 270
 271   return bytes_read ? bytes_read : rv;
 272 }
 273
 274 int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
 275                                  char* data, int size) {
 276   base::ThreadRestrictions::AssertIOAllowed();
 277   if (file < 0)
 278     return -1;
 279
 280   return HANDLE_EINTR(pread(file, data, size, offset));
 281 }
 282
 283 int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
 284                                        char* data, int size) {
 285   base::ThreadRestrictions::AssertIOAllowed();
 286   if (file < 0 || size < 0)
 287     return -1;
 288
 289   return HANDLE_EINTR(read(file, data, size));
 290 }
 291
 292 int WritePlatformFile(PlatformFile file, int64 offset,
 293                       const char* data, int size) {
 294   base::ThreadRestrictions::AssertIOAllowed();
 295
 296   if (IsOpenAppend(file))
 297     return WritePlatformFileAtCurrentPos(file, data, size);
 298
 299   if (file < 0 || size < 0)
 300     return -1;
 301
 302   int bytes_written = 0;
 303   int rv;
 304   do {
 305     rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
 306                              size - bytes_written, offset + bytes_written));
 307     if (rv <= 0)
 308       break;
 309
 310     bytes_written += rv;
 311   } while (bytes_written < size);
 312
 313   return bytes_written ? bytes_written : rv;
 314 }
 315
 316 int WritePlatformFileAtCurrentPos(PlatformFile file,
 317                                   const char* data, int size) {
 318   base::ThreadRestrictions::AssertIOAllowed();
 319   if (file < 0 || size < 0)
 320     return -1;
 321
 322   int bytes_written = 0;
 323   int rv;
 324   do {
 325     rv = HANDLE_EINTR(write(file, data, size));
 326     if (rv <= 0)
 327       break;
 328
 329     bytes_written += rv;
 330   } while (bytes_written < size);
 331
 332   return bytes_written ? bytes_written : rv;
 333 }
 334
 335 int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
 336                                         const char* data, int size) {
 337   base::ThreadRestrictions::AssertIOAllowed();
 338   if (file < 0 || size < 0)
 339     return -1;
 340
 341   return HANDLE_EINTR(write(file, data, size));
 342 }
 343
 344 bool TruncatePlatformFile(PlatformFile file, int64 length) {
 345   base::ThreadRestrictions::AssertIOAllowed();
 346   return ((file >= 0) && !CallFtruncate(file, length));
 347 }
 348
 349 bool FlushPlatformFile(PlatformFile file) {
 350   base::ThreadRestrictions::AssertIOAllowed();
 351   return !CallFsync(file);
 352 }
 353
 354 bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
 355                        const base::Time& last_modified_time) {
 356   base::ThreadRestrictions::AssertIOAllowed();
 357   if (file < 0)
 358     return false;
 359
 360   timeval times[2];
 361   times[0] = last_access_time.ToTimeVal();
 362   times[1] = last_modified_time.ToTimeVal();
 363
 364   return !CallFutimes(file, times);
 365 }
 366
 367 bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info) {
 368   if (!info)
 369     return false;
 370
 371   stat_wrapper_t file_info;
 372   if (CallFstat(file, &file_info))
 373     return false;
 374
 375   info->is_directory = S_ISDIR(file_info.st_mode);
 376   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
 377   info->size = file_info.st_size;
 378
 379 #if defined(OS_LINUX)
 380   const time_t last_modified_sec = file_info.st_mtim.tv_sec;
 381   const int64 last_modified_nsec = file_info.st_mtim.tv_nsec;
 382   const time_t last_accessed_sec = file_info.st_atim.tv_sec;
 383   const int64 last_accessed_nsec = file_info.st_atim.tv_nsec;
 384   const time_t creation_time_sec = file_info.st_ctim.tv_sec;
 385   const int64 creation_time_nsec = file_info.st_ctim.tv_nsec;
 386 #elif defined(OS_ANDROID)
 387   const time_t last_modified_sec = file_info.st_mtime;
 388   const int64 last_modified_nsec = file_info.st_mtime_nsec;
 389   const time_t last_accessed_sec = file_info.st_atime;
 390   const int64 last_accessed_nsec = file_info.st_atime_nsec;
 391   const time_t creation_time_sec = file_info.st_ctime;
 392   const int64 creation_time_nsec = file_info.st_ctime_nsec;
 393 #elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)
 394   const time_t last_modified_sec = file_info.st_mtimespec.tv_sec;
 395   const int64 last_modified_nsec = file_info.st_mtimespec.tv_nsec;
 396   const time_t last_accessed_sec = file_info.st_atimespec.tv_sec;
 397   const int64 last_accessed_nsec = file_info.st_atimespec.tv_nsec;
 398   const time_t creation_time_sec = file_info.st_ctimespec.tv_sec;
 399   const int64 creation_time_nsec = file_info.st_ctimespec.tv_nsec;
 400 #else
 401   // TODO(gavinp): Investigate a good high resolution option for OS_NACL.
 402   const time_t last_modified_sec = file_info.st_mtime;
 403   const int64 last_modified_nsec = 0;
 404   const time_t last_accessed_sec = file_info.st_atime;
 405   const int64 last_accessed_nsec = 0;
 406   const time_t creation_time_sec = file_info.st_ctime;
 407   const int64 creation_time_nsec = 0;
 408 #endif
 409
 410   info->last_modified =
 411       base::Time::FromTimeT(last_modified_sec) +
 412       base::TimeDelta::FromMicroseconds(last_modified_nsec /
 413                                         base::Time::kNanosecondsPerMicrosecond);
 414   info->last_accessed =
 415       base::Time::FromTimeT(last_accessed_sec) +
 416       base::TimeDelta::FromMicroseconds(last_accessed_nsec /
 417                                         base::Time::kNanosecondsPerMicrosecond);
 418   info->creation_time =
 419       base::Time::FromTimeT(creation_time_sec) +
 420       base::TimeDelta::FromMicroseconds(creation_time_nsec /
 421                                         base::Time::kNanosecondsPerMicrosecond);
 422   return true;
 423 }
 424
 425 PlatformFileError LockPlatformFile(PlatformFile file) {
 426   return CallFctnlFlock(file, true);
 427 }
 428
 429 PlatformFileError UnlockPlatformFile(PlatformFile file) {
 430   return CallFctnlFlock(file, false);
 431 }
 432
 433 PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
 434   switch (saved_errno) {
 435     case EACCES:
 436     case EISDIR:
 437     case EROFS:
 438     case EPERM:
 439       return PLATFORM_FILE_ERROR_ACCESS_DENIED;
 440 #if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
 441     case ETXTBSY:
 442       return PLATFORM_FILE_ERROR_IN_USE;
 443 #endif
 444     case EEXIST:
 445       return PLATFORM_FILE_ERROR_EXISTS;
 446     case ENOENT:
 447       return PLATFORM_FILE_ERROR_NOT_FOUND;
 448     case EMFILE:
 449       return PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
 450     case ENOMEM:
 451       return PLATFORM_FILE_ERROR_NO_MEMORY;
 452     case ENOSPC:
 453       return PLATFORM_FILE_ERROR_NO_SPACE;
 454     case ENOTDIR:
 455       return PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
 456     default:
 457 #if !defined(OS_NACL)  // NaCl build has no metrics code.
 458       UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Posix",
 459                                   saved_errno);
 460 #endif
 461       return PLATFORM_FILE_ERROR_FAILED;
 462   }
 463 }
 464
 465 }  // namespace base