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/threading/thread_restrictions.h"
  17 #include "base/utf_string_conversions.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 #if defined(OS_BSD) || defined(OS_MACOSX)
  31 typedef struct stat stat_wrapper_t;
  32 static int CallFstat(int fd, stat_wrapper_t *sb) {
  33   base::ThreadRestrictions::AssertIOAllowed();
  34   return fstat(fd, sb);
  35 }
  36 #else
  37 typedef struct stat64 stat_wrapper_t;
  38 static int CallFstat(int fd, stat_wrapper_t *sb) {
  39   base::ThreadRestrictions::AssertIOAllowed();
  40   return fstat64(fd, sb);
  41 }
  42 #endif
  43
  44 // TODO(erikkay): does it make sense to support PLATFORM_FILE_EXCLUSIVE_* here?
  45 PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
  46                                       int flags,
  47                                       bool* created,
  48                                       PlatformFileError* error) {
  49   base::ThreadRestrictions::AssertIOAllowed();
  50
  51   int open_flags = 0;
  52   if (flags & PLATFORM_FILE_CREATE)
  53     open_flags = O_CREAT | O_EXCL;
  54
  55   if (created)
  56     *created = false;
  57
  58   if (flags & PLATFORM_FILE_CREATE_ALWAYS) {
  59     DCHECK(!open_flags);
  60     open_flags = O_CREAT | O_TRUNC;
  61   }
  62
  63   if (flags & PLATFORM_FILE_OPEN_TRUNCATED) {
  64     DCHECK(!open_flags);
  65     DCHECK(flags & PLATFORM_FILE_WRITE);
  66     open_flags = O_TRUNC;
  67   }
  68
  69   if (!open_flags && !(flags & PLATFORM_FILE_OPEN) &&
  70       !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
  71     NOTREACHED();
  72     errno = EOPNOTSUPP;
  73     if (error)
  74       *error = PLATFORM_FILE_ERROR_FAILED;
  75     return kInvalidPlatformFileValue;
  76   }
  77
  78   if (flags & PLATFORM_FILE_WRITE && flags & PLATFORM_FILE_READ) {
  79     open_flags |= O_RDWR;
  80   } else if (flags & PLATFORM_FILE_WRITE) {
  81     open_flags |= O_WRONLY;
  82   } else if (!(flags & PLATFORM_FILE_READ) &&
  83              !(flags & PLATFORM_FILE_WRITE_ATTRIBUTES) &&
  84              !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
  85     NOTREACHED();
  86   }
  87
  88   if (flags & PLATFORM_FILE_TERMINAL_DEVICE)
  89     open_flags |= O_NOCTTY | O_NDELAY;
  90
  91   COMPILE_ASSERT(O_RDONLY == 0, O_RDONLY_must_equal_zero);
  92
  93   int mode = S_IRUSR | S_IWUSR;
  94 #if defined(OS_CHROMEOS)
  95   mode |= S_IRGRP | S_IROTH;
  96 #endif
  97
  98   int descriptor =
  99       HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));
 100
 101   if (flags & PLATFORM_FILE_OPEN_ALWAYS) {
 102     if (descriptor < 0) {
 103       open_flags |= O_CREAT;
 104       if (flags & PLATFORM_FILE_EXCLUSIVE_READ ||
 105           flags & PLATFORM_FILE_EXCLUSIVE_WRITE) {
 106         open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW
 107       }
 108       descriptor = HANDLE_EINTR(
 109           open(name.value().c_str(), open_flags, mode));
 110       if (created && descriptor >= 0)
 111         *created = true;
 112     }
 113   }
 114
 115   if (created && (descriptor >= 0) &&
 116       (flags & (PLATFORM_FILE_CREATE_ALWAYS | PLATFORM_FILE_CREATE)))
 117     *created = true;
 118
 119   if ((descriptor >= 0) && (flags & PLATFORM_FILE_DELETE_ON_CLOSE)) {
 120     unlink(name.value().c_str());
 121   }
 122
 123   if (error) {
 124     if (descriptor >= 0)
 125       *error = PLATFORM_FILE_OK;
 126     else
 127       *error = ErrnoToPlatformFileError(errno);
 128   }
 129
 130   return descriptor;
 131 }
 132
 133 FILE* FdopenPlatformFile(PlatformFile file, const char* mode) {
 134   return fdopen(file, mode);
 135 }
 136
 137 bool ClosePlatformFile(PlatformFile file) {
 138   base::ThreadRestrictions::AssertIOAllowed();
 139   return !HANDLE_EINTR(close(file));
 140 }
 141
 142 int64 SeekPlatformFile(PlatformFile file,
 143                        PlatformFileWhence whence,
 144                        int64 offset) {
 145   base::ThreadRestrictions::AssertIOAllowed();
 146   if (file < 0 || offset < 0)
 147     return -1;
 148
 149   return lseek(file, static_cast<off_t>(offset), static_cast<int>(whence));
 150 }
 151
 152 int ReadPlatformFile(PlatformFile file, int64 offset, char* data, int size) {
 153   base::ThreadRestrictions::AssertIOAllowed();
 154   if (file < 0 || size < 0)
 155     return -1;
 156
 157   int bytes_read = 0;
 158   int rv;
 159   do {
 160     rv = HANDLE_EINTR(pread(file, data + bytes_read,
 161                             size - bytes_read, offset + bytes_read));
 162     if (rv <= 0)
 163       break;
 164
 165     bytes_read += rv;
 166   } while (bytes_read < size);
 167
 168   return bytes_read ? bytes_read : rv;
 169 }
 170
 171 int ReadPlatformFileAtCurrentPos(PlatformFile file, char* data, int size) {
 172   base::ThreadRestrictions::AssertIOAllowed();
 173   if (file < 0 || size < 0)
 174     return -1;
 175
 176   int bytes_read = 0;
 177   int rv;
 178   do {
 179     rv = HANDLE_EINTR(read(file, data, size));
 180     if (rv <= 0)
 181       break;
 182
 183     bytes_read += rv;
 184   } while (bytes_read < size);
 185
 186   return bytes_read ? bytes_read : rv;
 187 }
 188
 189 int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
 190                                  char* data, int size) {
 191   base::ThreadRestrictions::AssertIOAllowed();
 192   if (file < 0)
 193     return -1;
 194
 195   return HANDLE_EINTR(pread(file, data, size, offset));
 196 }
 197
 198 int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
 199                                        char* data, int size) {
 200   base::ThreadRestrictions::AssertIOAllowed();
 201   if (file < 0 || size < 0)
 202     return -1;
 203
 204   return HANDLE_EINTR(read(file, data, size));
 205 }
 206
 207 int WritePlatformFile(PlatformFile file, int64 offset,
 208                       const char* data, int size) {
 209   base::ThreadRestrictions::AssertIOAllowed();
 210   if (file < 0 || size < 0)
 211     return -1;
 212
 213   int bytes_written = 0;
 214   int rv;
 215   do {
 216     rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
 217                              size - bytes_written, offset + bytes_written));
 218     if (rv <= 0)
 219       break;
 220
 221     bytes_written += rv;
 222   } while (bytes_written < size);
 223
 224   return bytes_written ? bytes_written : rv;
 225 }
 226
 227 int WritePlatformFileAtCurrentPos(PlatformFile file,
 228                                   const char* data, int size) {
 229   base::ThreadRestrictions::AssertIOAllowed();
 230   if (file < 0 || size < 0)
 231     return -1;
 232
 233   int bytes_written = 0;
 234   int rv;
 235   do {
 236     rv = HANDLE_EINTR(write(file, data, size));
 237     if (rv <= 0)
 238       break;
 239
 240     bytes_written += rv;
 241   } while (bytes_written < size);
 242
 243   return bytes_written ? bytes_written : rv;
 244 }
 245
 246 int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
 247                                         const char* data, int size) {
 248   base::ThreadRestrictions::AssertIOAllowed();
 249   if (file < 0 || size < 0)
 250     return -1;
 251
 252   return HANDLE_EINTR(write(file, data, size));
 253 }
 254
 255 bool TruncatePlatformFile(PlatformFile file, int64 length) {
 256   base::ThreadRestrictions::AssertIOAllowed();
 257   return ((file >= 0) && !HANDLE_EINTR(ftruncate(file, length)));
 258 }
 259
 260 bool FlushPlatformFile(PlatformFile file) {
 261   base::ThreadRestrictions::AssertIOAllowed();
 262   return !HANDLE_EINTR(fsync(file));
 263 }
 264
 265 bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
 266                        const base::Time& last_modified_time) {
 267   base::ThreadRestrictions::AssertIOAllowed();
 268   if (file < 0)
 269     return false;
 270
 271   timeval times[2];
 272   times[0] = last_access_time.ToTimeVal();
 273   times[1] = last_modified_time.ToTimeVal();
 274
 275 #ifdef __USE_XOPEN2K8
 276   // futimens should be available, but futimes might not be
 277   // http://pubs.opengroup.org/onlinepubs/9699919799/
 278
 279   timespec ts_times[2];
 280   ts_times[0].tv_sec  = times[0].tv_sec;
 281   ts_times[0].tv_nsec = times[0].tv_usec * 1000;
 282   ts_times[1].tv_sec  = times[1].tv_sec;
 283   ts_times[1].tv_nsec = times[1].tv_usec * 1000;
 284
 285   return !futimens(file, ts_times);
 286 #else
 287   return !futimes(file, times);
 288 #endif
 289 }
 290
 291 bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info) {
 292   if (!info)
 293     return false;
 294
 295   stat_wrapper_t file_info;
 296   if (CallFstat(file, &file_info))
 297     return false;
 298
 299   info->is_directory = S_ISDIR(file_info.st_mode);
 300   info->is_symbolic_link = S_ISLNK(file_info.st_mode);
 301   info->size = file_info.st_size;
 302   info->last_modified = base::Time::FromTimeT(file_info.st_mtime);
 303   info->last_accessed = base::Time::FromTimeT(file_info.st_atime);
 304   info->creation_time = base::Time::FromTimeT(file_info.st_ctime);
 305   return true;
 306 }
 307
 308 PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
 309   switch (saved_errno) {
 310     case EACCES:
 311     case EISDIR:
 312     case EROFS:
 313     case EPERM:
 314       return PLATFORM_FILE_ERROR_ACCESS_DENIED;
 315     case ETXTBSY:
 316       return PLATFORM_FILE_ERROR_IN_USE;
 317     case EEXIST:
 318       return PLATFORM_FILE_ERROR_EXISTS;
 319     case ENOENT:
 320       return PLATFORM_FILE_ERROR_NOT_FOUND;
 321     case EMFILE:
 322       return PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
 323     case ENOMEM:
 324       return PLATFORM_FILE_ERROR_NO_MEMORY;
 325     case ENOSPC:
 326       return PLATFORM_FILE_ERROR_NO_SPACE;
 327     case ENOTDIR:
 328       return PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
 329     default:
 330 #if !defined(OS_NACL)  // NaCl build has no metrics code.
 331       UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Posix",
 332                                   saved_errno);
 333 #endif
 334       return PLATFORM_FILE_ERROR_FAILED;
 335   }
 336 }
 337
 338 }  // namespace base