base/platform_file

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This source file includes following definitions.
CallFstat
CallFstat
IsOpenAppend
CallFtruncate
CallFsync
CallFutimes
CallFctnlFlock
IsOpenAppend
CallFtruncate
CallFsync
CallFutimes
CallFctnlFlock
CreatePlatformFileUnsafe
FdopenPlatformFile
ClosePlatformFile
SeekPlatformFile
ReadPlatformFile
ReadPlatformFileAtCurrentPos
ReadPlatformFileNoBestEffort
ReadPlatformFileCurPosNoBestEffort
WritePlatformFile
WritePlatformFileAtCurrentPos
WritePlatformFileCurPosNoBestEffort
TruncatePlatformFile
FlushPlatformFile
TouchPlatformFile
GetPlatformFileInfo
LockPlatformFile
UnlockPlatformFile
ErrnoToPlatformFileError
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "base/platform_file.h"

#include <fcntl.h>
#include <errno.h>
#include <sys/stat.h>
#include <unistd.h>

#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/metrics/sparse_histogram.h"
#include "base/posix/eintr_wrapper.h"
#include "base/strings/utf_string_conversions.h"
#include "base/threading/thread_restrictions.h"

#if defined(OS_ANDROID)
#include "base/os_compat_android.h"
#endif

namespace base {

// Make sure our Whence mappings match the system headers.
COMPILE_ASSERT(PLATFORM_FILE_FROM_BEGIN   == SEEK_SET &&
               PLATFORM_FILE_FROM_CURRENT == SEEK_CUR &&
               PLATFORM_FILE_FROM_END     == SEEK_END, whence_matches_system);

namespace {

#if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)
typedef struct stat stat_wrapper_t;
static int CallFstat(int fd, stat_wrapper_t *sb) {
  base::ThreadRestrictions::AssertIOAllowed();
  return fstat(fd, sb);
}
#else
typedef struct stat64 stat_wrapper_t;
static int CallFstat(int fd, stat_wrapper_t *sb) {
  base::ThreadRestrictions::AssertIOAllowed();
  return fstat64(fd, sb);
}
#endif

// NaCl doesn't provide the following system calls, so either simulate them or
// wrap them in order to minimize the number of #ifdef's in this file.
#if !defined(OS_NACL)
static bool IsOpenAppend(PlatformFile file) {
  return (fcntl(file, F_GETFL) & O_APPEND) != 0;
}

static int CallFtruncate(PlatformFile file, int64 length) {
  return HANDLE_EINTR(ftruncate(file, length));
}

static int CallFsync(PlatformFile file) {
  return HANDLE_EINTR(fsync(file));
}

static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
#ifdef __USE_XOPEN2K8
  // futimens should be available, but futimes might not be
  // http://pubs.opengroup.org/onlinepubs/9699919799/

  timespec ts_times[2];
  ts_times[0].tv_sec  = times[0].tv_sec;
  ts_times[0].tv_nsec = times[0].tv_usec * 1000;
  ts_times[1].tv_sec  = times[1].tv_sec;
  ts_times[1].tv_nsec = times[1].tv_usec * 1000;

  return futimens(file, ts_times);
#else
  return futimes(file, times);
#endif
}

static PlatformFileError CallFctnlFlock(PlatformFile file, bool do_lock) {
  struct flock lock;
  lock.l_type = F_WRLCK;
  lock.l_whence = SEEK_SET;
  lock.l_start = 0;
  lock.l_len = 0;  // Lock entire file.
  if (HANDLE_EINTR(fcntl(file, do_lock ? F_SETLK : F_UNLCK, &lock)) == -1)
    return ErrnoToPlatformFileError(errno);
  return PLATFORM_FILE_OK;
}
#else  // defined(OS_NACL)

static bool IsOpenAppend(PlatformFile file) {
  // NaCl doesn't implement fcntl. Since NaCl's write conforms to the POSIX
  // standard and always appends if the file is opened with O_APPEND, just
  // return false here.
  return false;
}

static int CallFtruncate(PlatformFile file, int64 length) {
  NOTIMPLEMENTED();  // NaCl doesn't implement ftruncate.
  return 0;
}

static int CallFsync(PlatformFile file) {
  NOTIMPLEMENTED();  // NaCl doesn't implement fsync.
  return 0;
}

static int CallFutimes(PlatformFile file, const struct timeval times[2]) {
  NOTIMPLEMENTED();  // NaCl doesn't implement futimes.
  return 0;
}

static PlatformFileError CallFctnlFlock(PlatformFile file, bool do_lock) {
  NOTIMPLEMENTED();  // NaCl doesn't implement flock struct.
  return PLATFORM_FILE_ERROR_INVALID_OPERATION;
}
#endif  // defined(OS_NACL)

}  // namespace

// NaCl doesn't implement system calls to open files directly.
#if !defined(OS_NACL)
// TODO(erikkay): does it make sense to support PLATFORM_FILE_EXCLUSIVE_* here?
PlatformFile CreatePlatformFileUnsafe(const FilePath& name,
                                      int flags,
                                      bool* created,
                                      PlatformFileError* error) {
  base::ThreadRestrictions::AssertIOAllowed();

  int open_flags = 0;
  if (flags & PLATFORM_FILE_CREATE)
    open_flags = O_CREAT | O_EXCL;

  if (created)
    *created = false;

  if (flags & PLATFORM_FILE_CREATE_ALWAYS) {
    DCHECK(!open_flags);
    open_flags = O_CREAT | O_TRUNC;
  }

  if (flags & PLATFORM_FILE_OPEN_TRUNCATED) {
    DCHECK(!open_flags);
    DCHECK(flags & PLATFORM_FILE_WRITE);
    open_flags = O_TRUNC;
  }

  if (!open_flags && !(flags & PLATFORM_FILE_OPEN) &&
      !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
    NOTREACHED();
    errno = EOPNOTSUPP;
    if (error)
      *error = PLATFORM_FILE_ERROR_FAILED;
    return kInvalidPlatformFileValue;
  }

  if (flags & PLATFORM_FILE_WRITE && flags & PLATFORM_FILE_READ) {
    open_flags |= O_RDWR;
  } else if (flags & PLATFORM_FILE_WRITE) {
    open_flags |= O_WRONLY;
  } else if (!(flags & PLATFORM_FILE_READ) &&
             !(flags & PLATFORM_FILE_WRITE_ATTRIBUTES) &&
             !(flags & PLATFORM_FILE_APPEND) &&
             !(flags & PLATFORM_FILE_OPEN_ALWAYS)) {
    NOTREACHED();
  }

  if (flags & PLATFORM_FILE_TERMINAL_DEVICE)
    open_flags |= O_NOCTTY | O_NDELAY;

  if (flags & PLATFORM_FILE_APPEND && flags & PLATFORM_FILE_READ)
    open_flags |= O_APPEND | O_RDWR;
  else if (flags & PLATFORM_FILE_APPEND)
    open_flags |= O_APPEND | O_WRONLY;

  COMPILE_ASSERT(O_RDONLY == 0, O_RDONLY_must_equal_zero);

  int mode = S_IRUSR | S_IWUSR;
#if defined(OS_CHROMEOS)
  mode |= S_IRGRP | S_IROTH;
#endif

  int descriptor =
      HANDLE_EINTR(open(name.value().c_str(), open_flags, mode));

  if (flags & PLATFORM_FILE_OPEN_ALWAYS) {
    if (descriptor < 0) {
      open_flags |= O_CREAT;
      if (flags & PLATFORM_FILE_EXCLUSIVE_READ ||
          flags & PLATFORM_FILE_EXCLUSIVE_WRITE) {
        open_flags |= O_EXCL;   // together with O_CREAT implies O_NOFOLLOW
      }
      descriptor = HANDLE_EINTR(
          open(name.value().c_str(), open_flags, mode));
      if (created && descriptor >= 0)
        *created = true;
    }
  }

  if (created && (descriptor >= 0) &&
      (flags & (PLATFORM_FILE_CREATE_ALWAYS | PLATFORM_FILE_CREATE)))
    *created = true;

  if ((descriptor >= 0) && (flags & PLATFORM_FILE_DELETE_ON_CLOSE)) {
    unlink(name.value().c_str());
  }

  if (error) {
    if (descriptor >= 0)
      *error = PLATFORM_FILE_OK;
    else
      *error = ErrnoToPlatformFileError(errno);
  }

  return descriptor;
}

FILE* FdopenPlatformFile(PlatformFile file, const char* mode) {
  return fdopen(file, mode);
}
#endif  // !defined(OS_NACL)

bool ClosePlatformFile(PlatformFile file) {
  base::ThreadRestrictions::AssertIOAllowed();
  return !IGNORE_EINTR(close(file));
}

int64 SeekPlatformFile(PlatformFile file,
                       PlatformFileWhence whence,
                       int64 offset) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0 || offset < 0)
    return -1;

  return lseek(file, static_cast<off_t>(offset), static_cast<int>(whence));
}

int ReadPlatformFile(PlatformFile file, int64 offset, char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0 || size < 0)
    return -1;

  int bytes_read = 0;
  int rv;
  do {
    rv = HANDLE_EINTR(pread(file, data + bytes_read,
                            size - bytes_read, offset + bytes_read));
    if (rv <= 0)
      break;

    bytes_read += rv;
  } while (bytes_read < size);

  return bytes_read ? bytes_read : rv;
}

int ReadPlatformFileAtCurrentPos(PlatformFile file, char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0 || size < 0)
    return -1;

  int bytes_read = 0;
  int rv;
  do {
    rv = HANDLE_EINTR(read(file, data + bytes_read, size - bytes_read));
    if (rv <= 0)
      break;

    bytes_read += rv;
  } while (bytes_read < size);

  return bytes_read ? bytes_read : rv;
}

int ReadPlatformFileNoBestEffort(PlatformFile file, int64 offset,
                                 char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0)
    return -1;

  return HANDLE_EINTR(pread(file, data, size, offset));
}

int ReadPlatformFileCurPosNoBestEffort(PlatformFile file,
                                       char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0 || size < 0)
    return -1;

  return HANDLE_EINTR(read(file, data, size));
}

int WritePlatformFile(PlatformFile file, int64 offset,
                      const char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();

  if (IsOpenAppend(file))
    return WritePlatformFileAtCurrentPos(file, data, size);

  if (file < 0 || size < 0)
    return -1;

  int bytes_written = 0;
  int rv;
  do {
    rv = HANDLE_EINTR(pwrite(file, data + bytes_written,
                             size - bytes_written, offset + bytes_written));
    if (rv <= 0)
      break;

    bytes_written += rv;
  } while (bytes_written < size);

  return bytes_written ? bytes_written : rv;
}

int WritePlatformFileAtCurrentPos(PlatformFile file,
                                  const char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0 || size < 0)
    return -1;

  int bytes_written = 0;
  int rv;
  do {
    rv = HANDLE_EINTR(write(file, data + bytes_written, size - bytes_written));
    if (rv <= 0)
      break;

    bytes_written += rv;
  } while (bytes_written < size);

  return bytes_written ? bytes_written : rv;
}

int WritePlatformFileCurPosNoBestEffort(PlatformFile file,
                                        const char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0 || size < 0)
    return -1;

  return HANDLE_EINTR(write(file, data, size));
}

bool TruncatePlatformFile(PlatformFile file, int64 length) {
  base::ThreadRestrictions::AssertIOAllowed();
  return ((file >= 0) && !CallFtruncate(file, length));
}

bool FlushPlatformFile(PlatformFile file) {
  base::ThreadRestrictions::AssertIOAllowed();
  return !CallFsync(file);
}

bool TouchPlatformFile(PlatformFile file, const base::Time& last_access_time,
                       const base::Time& last_modified_time) {
  base::ThreadRestrictions::AssertIOAllowed();
  if (file < 0)
    return false;

  timeval times[2];
  times[0] = last_access_time.ToTimeVal();
  times[1] = last_modified_time.ToTimeVal();

  return !CallFutimes(file, times);
}

bool GetPlatformFileInfo(PlatformFile file, PlatformFileInfo* info) {
  if (!info)
    return false;

  stat_wrapper_t file_info;
  if (CallFstat(file, &file_info))
    return false;

  info->is_directory = S_ISDIR(file_info.st_mode);
  info->is_symbolic_link = S_ISLNK(file_info.st_mode);
  info->size = file_info.st_size;

#if defined(OS_LINUX)
  const time_t last_modified_sec = file_info.st_mtim.tv_sec;
  const int64 last_modified_nsec = file_info.st_mtim.tv_nsec;
  const time_t last_accessed_sec = file_info.st_atim.tv_sec;
  const int64 last_accessed_nsec = file_info.st_atim.tv_nsec;
  const time_t creation_time_sec = file_info.st_ctim.tv_sec;
  const int64 creation_time_nsec = file_info.st_ctim.tv_nsec;
#elif defined(OS_ANDROID)
  const time_t last_modified_sec = file_info.st_mtime;
  const int64 last_modified_nsec = file_info.st_mtime_nsec;
  const time_t last_accessed_sec = file_info.st_atime;
  const int64 last_accessed_nsec = file_info.st_atime_nsec;
  const time_t creation_time_sec = file_info.st_ctime;
  const int64 creation_time_nsec = file_info.st_ctime_nsec;
#elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)
  const time_t last_modified_sec = file_info.st_mtimespec.tv_sec;
  const int64 last_modified_nsec = file_info.st_mtimespec.tv_nsec;
  const time_t last_accessed_sec = file_info.st_atimespec.tv_sec;
  const int64 last_accessed_nsec = file_info.st_atimespec.tv_nsec;
  const time_t creation_time_sec = file_info.st_ctimespec.tv_sec;
  const int64 creation_time_nsec = file_info.st_ctimespec.tv_nsec;
#else
  // TODO(gavinp): Investigate a good high resolution option for OS_NACL.
  const time_t last_modified_sec = file_info.st_mtime;
  const int64 last_modified_nsec = 0;
  const time_t last_accessed_sec = file_info.st_atime;
  const int64 last_accessed_nsec = 0;
  const time_t creation_time_sec = file_info.st_ctime;
  const int64 creation_time_nsec = 0;
#endif

  info->last_modified =
      base::Time::FromTimeT(last_modified_sec) +
      base::TimeDelta::FromMicroseconds(last_modified_nsec /
                                        base::Time::kNanosecondsPerMicrosecond);
  info->last_accessed =
      base::Time::FromTimeT(last_accessed_sec) +
      base::TimeDelta::FromMicroseconds(last_accessed_nsec /
                                        base::Time::kNanosecondsPerMicrosecond);
  info->creation_time =
      base::Time::FromTimeT(creation_time_sec) +
      base::TimeDelta::FromMicroseconds(creation_time_nsec /
                                        base::Time::kNanosecondsPerMicrosecond);
  return true;
}

PlatformFileError LockPlatformFile(PlatformFile file) {
  return CallFctnlFlock(file, true);
}

PlatformFileError UnlockPlatformFile(PlatformFile file) {
  return CallFctnlFlock(file, false);
}

PlatformFileError ErrnoToPlatformFileError(int saved_errno) {
  switch (saved_errno) {
    case EACCES:
    case EISDIR:
    case EROFS:
    case EPERM:
      return PLATFORM_FILE_ERROR_ACCESS_DENIED;
#if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
    case ETXTBSY:
      return PLATFORM_FILE_ERROR_IN_USE;
#endif
    case EEXIST:
      return PLATFORM_FILE_ERROR_EXISTS;
    case ENOENT:
      return PLATFORM_FILE_ERROR_NOT_FOUND;
    case EMFILE:
      return PLATFORM_FILE_ERROR_TOO_MANY_OPENED;
    case ENOMEM:
      return PLATFORM_FILE_ERROR_NO_MEMORY;
    case ENOSPC:
      return PLATFORM_FILE_ERROR_NO_SPACE;
    case ENOTDIR:
      return PLATFORM_FILE_ERROR_NOT_A_DIRECTORY;
    default:
#if !defined(OS_NACL)  // NaCl build has no metrics code.
      UMA_HISTOGRAM_SPARSE_SLOWLY("PlatformFile.UnknownErrors.Posix",
                                  saved_errno);
#endif
      return PLATFORM_FILE_ERROR_FAILED;
  }
}

}  // namespace base
/* [<][>][^][v][top][bottom][index][help] */
root/base/platform_file_posix.cc

DEFINITIONS
