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 bool ClosePlatformFile(PlatformFile file) {
 121   base::ThreadRestrictions::AssertIOAllowed();
 122   return !IGNORE_EINTR(close(file));
 123 }
 124
 125 int64 SeekPlatformFile(PlatformFile file,
 126                        PlatformFileWhence whence,
 127                        int64 offset) {
 128   base::ThreadRestrictions::AssertIOAllowed();
 129   if (file < 0 || offset < 0)
 130     return -1;
 131
 132   return lseek(file, static_cast<off_t>(offset), static_cast<int>(whence));
 133 }
 134
 135 int ReadPlatformFile(PlatformFile file, int64 offset, char* data, int size) {
 136   base::ThreadRestrictions::AssertIOAllowed();
 137   if (file < 0 || size < 0)
 138     return -1;
 139
 140   int bytes_read = 0;
 141   int rv;
 142   do {
 143     rv = HANDLE_EINTR(pread(file, data + bytes_read,
 144                             size - bytes_read, offset + bytes_read));
 145     if (rv <= 0)
 146       break;
 147
 148     bytes_read += rv;
 149   } while (bytes_read < size);
 150
 151   return bytes_read ? bytes_read : rv;
 152 }
 153
 154 int ReadPlatformFileAtCurrentPos(PlatformFile file, char* data, int size) {
 155   base::ThreadRestrictions::AssertIOAllowed();
 156   if (file < 0 || size < 0)
 157     return -1;
 158
 159   int bytes_read = 0;
 160   int rv;
 161   do {
 162     rv = HANDLE_EINTR(read(file, data + bytes_read, size - bytes_read));
 163     if (rv <= 0)
 164       break;
 165
 166     bytes_read += rv;
 167   } while (bytes_read < size);
 168
 169   return bytes_read ? bytes_read : rv;
 170 }
 171
 172 int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
 173                                  char* data, int size) {
 174   base::ThreadRestrictions::AssertIOAllowed();
 175   if (file < 0)
 176     return -1;
 177
 178   return HANDLE_EINTR(pread(file, data, size, offset));
 179 }
 180
 181 int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
 182                                        char* data, int size) {
 183   base::ThreadRestrictions::AssertIOAllowed();
 184   if (file < 0 || size < 0)
 185     return -1;
 186
 187   return HANDLE_EINTR(read(file, data, size));
 188 }
 189
 190 int WritePlatformFile(PlatformFile file, int64 offset,
 191                       const char* data, int size) {
 192   base::ThreadRestrictions::AssertIOAllowed();
 193
 194   if (IsOpenAppend(file))
 195     return WritePlatformFileAtCurrentPos(file, data, size);
 196
 197   if (file < 0 || size < 0)
 198     return -1;
 199
 200   int bytes_written = 0;
 201   int rv;
 202   do {
 203     rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
 204                              size - bytes_written, offset + bytes_written));
 205     if (rv <= 0)
 206       break;
 207
 208     bytes_written += rv;
 209   } while (bytes_written < size);
 210
 211   return bytes_written ? bytes_written : rv;
 212 }
 213
 214 int WritePlatformFileAtCurrentPos(PlatformFile file,
 215                                   const char* data, int size) {
 216   base::ThreadRestrictions::AssertIOAllowed();
 217   if (file < 0 || size < 0)
 218     return -1;
 219
 220   int bytes_written = 0;
 221   int rv;
 222   do {
 223     rv = HANDLE_EINTR(write(file, data + bytes_written, size - bytes_written));
 224     if (rv <= 0)
 225       break;
 226
 227     bytes_written += rv;
 228   } while (bytes_written < size);
 229
 230   return bytes_written ? bytes_written : rv;
 231 }
 232
 233 int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
 234                                         const char* data, int size) {
 235   base::ThreadRestrictions::AssertIOAllowed();
 236   if (file < 0 || size < 0)
 237     return -1;
 238
 239   return HANDLE_EINTR(write(file, data, size));
 240 }
 241
 242 bool TruncatePlatformFile(PlatformFile file, int64 length) {
 243   base::ThreadRestrictions::AssertIOAllowed();
 244   return ((file >= 0) && !CallFtruncate(file, length));
 245 }
 246
 247 bool FlushPlatformFile(PlatformFile file) {
 248   base::ThreadRestrictions::AssertIOAllowed();
 249   return !CallFsync(file);
 250 }
 251
 252 bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
 253                        const base::Time& last_modified_time) {
 254   base::ThreadRestrictions::AssertIOAllowed();
 255   if (file < 0)
 256     return false;
 257
 258   timeval times[2];
 259   times[0] = last_access_time.ToTimeVal();
 260   times[1] = last_modified_time.ToTimeVal();
 261
 262   return !CallFutimes(file, times);
 263 }
 264
 265 bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info) {
 266   if (!info)
 267     return false;
 268
 269   stat_wrapper_t file_info;
 270   if (CallFstat(file, &file_info))
 271     return false;
 272
 273   info->is_directory = S_ISDIR(file_info.st_mode);
 274   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
 275   info->size = file_info.st_size;
 276
 277 #if defined(OS_LINUX)
 278   const time_t last_modified_sec = file_info.st_mtim.tv_sec;
 279   const int64 last_modified_nsec = file_info.st_mtim.tv_nsec;
 280   const time_t last_accessed_sec = file_info.st_atim.tv_sec;
 281   const int64 last_accessed_nsec = file_info.st_atim.tv_nsec;
 282   const time_t creation_time_sec = file_info.st_ctim.tv_sec;
 283   const int64 creation_time_nsec = file_info.st_ctim.tv_nsec;
 284 #elif defined(OS_ANDROID)
 285   const time_t last_modified_sec = file_info.st_mtime;
 286   const int64 last_modified_nsec = file_info.st_mtime_nsec;
 287   const time_t last_accessed_sec = file_info.st_atime;
 288   const int64 last_accessed_nsec = file_info.st_atime_nsec;
 289   const time_t creation_time_sec = file_info.st_ctime;
 290   const int64 creation_time_nsec = file_info.st_ctime_nsec;
 291 #elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)
 292   const time_t last_modified_sec = file_info.st_mtimespec.tv_sec;
 293   const int64 last_modified_nsec = file_info.st_mtimespec.tv_nsec;
 294   const time_t last_accessed_sec = file_info.st_atimespec.tv_sec;
 295   const int64 last_accessed_nsec = file_info.st_atimespec.tv_nsec;
 296   const time_t creation_time_sec = file_info.st_ctimespec.tv_sec;
 297   const int64 creation_time_nsec = file_info.st_ctimespec.tv_nsec;
 298 #else
 299   // TODO(gavinp): Investigate a good high resolution option for OS_NACL.
 300   const time_t last_modified_sec = file_info.st_mtime;
 301   const int64 last_modified_nsec = 0;
 302   const time_t last_accessed_sec = file_info.st_atime;
 303   const int64 last_accessed_nsec = 0;
 304   const time_t creation_time_sec = file_info.st_ctime;
 305   const int64 creation_time_nsec = 0;
 306 #endif
 307
 308   info->last_modified =
 309       base::Time::FromTimeT(last_modified_sec) +
 310       base::TimeDelta::FromMicroseconds(last_modified_nsec /
 311                                         base::Time::kNanosecondsPerMicrosecond);
 312   info->last_accessed =
 313       base::Time::FromTimeT(last_accessed_sec) +
 314       base::TimeDelta::FromMicroseconds(last_accessed_nsec /
 315                                         base::Time::kNanosecondsPerMicrosecond);
 316   info->creation_time =
 317       base::Time::FromTimeT(creation_time_sec) +
 318       base::TimeDelta::FromMicroseconds(creation_time_nsec /
 319                                         base::Time::kNanosecondsPerMicrosecond);
 320   return true;
 321 }
 322
 323 PlatformFileError LockPlatformFile(PlatformFile file) {
 324   return CallFctnlFlock(file, true);
 325 }
 326
 327 PlatformFileError UnlockPlatformFile(PlatformFile file) {
 328   return CallFctnlFlock(file, false);
 329 }
 330
 331 PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
 332   switch (saved_errno) {
 333     case EACCES:
 334     case EISDIR:
 335     case EROFS:
 336     case EPERM:
 337       return PLATFORM_FILE_ERROR_ACCESS_DENIED;
 338 #if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
 339     case ETXTBSY:
 340       return PLATFORM_FILE_ERROR_IN_USE;
 341 #endif
 342     case EEXIST:
 343       return PLATFORM_FILE_ERROR_EXISTS;
 344     case ENOENT:
 345       return PLATFORM_FILE_ERROR_NOT_FOUND;
 346     case EMFILE:
 347       return PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
 348     case ENOMEM:
 349       return PLATFORM_FILE_ERROR_NO_MEMORY;
 350     case ENOSPC:
 351       return PLATFORM_FILE_ERROR_NO_SPACE;
 352     case ENOTDIR:
 353       return PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
 354     default:
 355 #if !defined(OS_NACL)  // NaCl build has no metrics code.
 356       UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Posix",
 357                                   saved_errno);
 358 #endif
 359       return PLATFORM_FILE_ERROR_FAILED;
 360   }
 361 }
 362
 363 }  // namespace base