base/files/file

/* [<][>][^][v][top][bottom][index][help] */
This source file includes following definitions.
CallFstat
CallFstat
IsOpenAppend
CallFtruncate
CallFsync
CallFutimes
CallFctnlFlock
IsOpenAppend
CallFtruncate
CallFsync
CallFutimes
CallFctnlFlock
FromStat
InitializeUnsafe
IsValid
GetPlatformFile
TakePlatformFile
Close
Seek
Read
ReadAtCurrentPos
ReadNoBestEffort
ReadAtCurrentPosNoBestEffort
Write
WriteAtCurrentPos
WriteAtCurrentPosNoBestEffort
GetLength
SetLength
Flush
SetTimes
GetInfo
Lock
Unlock
OSErrorToFileError
SetPlatformFile
// 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/files/file.h"

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

#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/metrics/sparse_histogram.h"
// TODO(rvargas): remove this (needed for kInvalidPlatformFileValue).
#include "base/platform_file.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(File::FROM_BEGIN   == SEEK_SET &&
               File::FROM_CURRENT == SEEK_CUR &&
               File::FROM_END     == SEEK_END, whence_matches_system);

namespace {

#if defined(OS_BSD) || defined(OS_MACOSX) || defined(OS_NACL)
static int CallFstat(int fd, stat_wrapper_t *sb) {
  base::ThreadRestrictions::AssertIOAllowed();
  return fstat(fd, sb);
}
#else
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 File::Error 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 File::OSErrorToFileError(errno);
  return File::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 File::Error CallFctnlFlock(PlatformFile file, bool do_lock) {
  NOTIMPLEMENTED();  // NaCl doesn't implement flock struct.
  return File::FILE_ERROR_INVALID_OPERATION;
}
#endif  // defined(OS_NACL)

}  // namespace

void File::Info::FromStat(const stat_wrapper_t& stat_info) {
  is_directory = S_ISDIR(stat_info.st_mode);
  is_symbolic_link = S_ISLNK(stat_info.st_mode);
  size = stat_info.st_size;

#if defined(OS_LINUX)
  time_t last_modified_sec = stat_info.st_mtim.tv_sec;
  int64 last_modified_nsec = stat_info.st_mtim.tv_nsec;
  time_t last_accessed_sec = stat_info.st_atim.tv_sec;
  int64 last_accessed_nsec = stat_info.st_atim.tv_nsec;
  time_t creation_time_sec = stat_info.st_ctim.tv_sec;
  int64 creation_time_nsec = stat_info.st_ctim.tv_nsec;
#elif defined(OS_ANDROID)
  time_t last_modified_sec = stat_info.st_mtime;
  int64 last_modified_nsec = stat_info.st_mtime_nsec;
  time_t last_accessed_sec = stat_info.st_atime;
  int64 last_accessed_nsec = stat_info.st_atime_nsec;
  time_t creation_time_sec = stat_info.st_ctime;
  int64 creation_time_nsec = stat_info.st_ctime_nsec;
#elif defined(OS_MACOSX) || defined(OS_IOS) || defined(OS_BSD)
  time_t last_modified_sec = stat_info.st_mtimespec.tv_sec;
  int64 last_modified_nsec = stat_info.st_mtimespec.tv_nsec;
  time_t last_accessed_sec = stat_info.st_atimespec.tv_sec;
  int64 last_accessed_nsec = stat_info.st_atimespec.tv_nsec;
  time_t creation_time_sec = stat_info.st_ctimespec.tv_sec;
  int64 creation_time_nsec = stat_info.st_ctimespec.tv_nsec;
#else
  time_t last_modified_sec = stat_info.st_mtime;
  int64 last_modified_nsec = 0;
  time_t last_accessed_sec = stat_info.st_atime;
  int64 last_accessed_nsec = 0;
  time_t creation_time_sec = stat_info.st_ctime;
  int64 creation_time_nsec = 0;
#endif

  last_modified =
      Time::FromTimeT(last_modified_sec) +
      TimeDelta::FromMicroseconds(last_modified_nsec /
                                  Time::kNanosecondsPerMicrosecond);

  last_accessed =
      Time::FromTimeT(last_accessed_sec) +
      TimeDelta::FromMicroseconds(last_accessed_nsec /
                                  Time::kNanosecondsPerMicrosecond);

  creation_time =
      Time::FromTimeT(creation_time_sec) +
      TimeDelta::FromMicroseconds(creation_time_nsec /
                                  Time::kNanosecondsPerMicrosecond);
}

// NaCl doesn't implement system calls to open files directly.
#if !defined(OS_NACL)
// TODO(erikkay): does it make sense to support FLAG_EXCLUSIVE_* here?
void File::InitializeUnsafe(const FilePath& name, uint32 flags) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(!IsValid());

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

  created_ = false;

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

  if (flags & FLAG_OPEN_TRUNCATED) {
    DCHECK(!open_flags);
    DCHECK(flags & FLAG_WRITE);
    open_flags = O_TRUNC;
  }

  if (!open_flags && !(flags & FLAG_OPEN) && !(flags & FLAG_OPEN_ALWAYS)) {
    NOTREACHED();
    errno = EOPNOTSUPP;
    error_details_ = FILE_ERROR_FAILED;
    return;
  }

  if (flags & FLAG_WRITE && flags & FLAG_READ) {
    open_flags |= O_RDWR;
  } else if (flags & FLAG_WRITE) {
    open_flags |= O_WRONLY;
  } else if (!(flags & FLAG_READ) &&
             !(flags & FLAG_WRITE_ATTRIBUTES) &&
             !(flags & FLAG_APPEND) &&
             !(flags & FLAG_OPEN_ALWAYS)) {
    NOTREACHED();
  }

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

  if (flags & FLAG_APPEND && flags & FLAG_READ)
    open_flags |= O_APPEND | O_RDWR;
  else if (flags & FLAG_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 & FLAG_OPEN_ALWAYS) {
    if (descriptor < 0) {
      open_flags |= O_CREAT;
      if (flags & FLAG_EXCLUSIVE_READ || flags & FLAG_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 (descriptor >= 0)
        created_ = true;
    }
  }

  if (descriptor < 0) {
    error_details_ = File::OSErrorToFileError(errno);
    return;
  }

  if (flags & (FLAG_CREATE_ALWAYS | FLAG_CREATE))
    created_ = true;

  if (flags & FLAG_DELETE_ON_CLOSE)
    unlink(name.value().c_str());

  async_ = ((flags & FLAG_ASYNC) == FLAG_ASYNC);
  error_details_ = FILE_OK;
  file_.reset(descriptor);
}
#endif  // !defined(OS_NACL)

bool File::IsValid() const {
  return file_.is_valid();
}

PlatformFile File::GetPlatformFile() const {
  return file_.get();
}

PlatformFile File::TakePlatformFile() {
  return file_.release();
}

void File::Close() {
  if (!IsValid())
    return;

  base::ThreadRestrictions::AssertIOAllowed();
  file_.reset();
}

int64 File::Seek(Whence whence, int64 offset) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  if (offset < 0)
    return -1;

  return lseek(file_.get(), static_cast<off_t>(offset),
               static_cast<int>(whence));
}

int File::Read(int64 offset, char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  if (size < 0)
    return -1;

  int bytes_read = 0;
  int rv;
  do {
    rv = HANDLE_EINTR(pread(file_.get(), 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 File::ReadAtCurrentPos(char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  if (size < 0)
    return -1;

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

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

  return bytes_read ? bytes_read : rv;
}

int File::ReadNoBestEffort(int64 offset, char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());

  return HANDLE_EINTR(pread(file_.get(), data, size, offset));
}

int File::ReadAtCurrentPosNoBestEffort(char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  if (size < 0)
    return -1;

  return HANDLE_EINTR(read(file_.get(), data, size));
}

int File::Write(int64 offset, const char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();

  if (IsOpenAppend(file_.get()))
    return WriteAtCurrentPos(data, size);

  DCHECK(IsValid());
  if (size < 0)
    return -1;

  int bytes_written = 0;
  int rv;
  do {
    rv = HANDLE_EINTR(pwrite(file_.get(), 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 File::WriteAtCurrentPos(const char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  if (size < 0)
    return -1;

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

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

  return bytes_written ? bytes_written : rv;
}

int File::WriteAtCurrentPosNoBestEffort(const char* data, int size) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  if (size < 0)
    return -1;

  return HANDLE_EINTR(write(file_.get(), data, size));
}

int64 File::GetLength() {
  DCHECK(IsValid());

  stat_wrapper_t file_info;
  if (CallFstat(file_.get(), &file_info))
    return false;

  return file_info.st_size;
}

bool File::SetLength(int64 length) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  return !CallFtruncate(file_.get(), length);
}

bool File::Flush() {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());
  return !CallFsync(file_.get());
}

bool File::SetTimes(Time last_access_time, Time last_modified_time) {
  base::ThreadRestrictions::AssertIOAllowed();
  DCHECK(IsValid());

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

  return !CallFutimes(file_.get(), times);
}

bool File::GetInfo(Info* info) {
  DCHECK(IsValid());

  stat_wrapper_t file_info;
  if (CallFstat(file_.get(), &file_info))
    return false;

  info->FromStat(file_info);
  return true;
}

File::Error File::Lock() {
  return CallFctnlFlock(file_.get(), true);
}

File::Error File::Unlock() {
  return CallFctnlFlock(file_.get(), false);
}

// Static.
File::Error File::OSErrorToFileError(int saved_errno) {
  switch (saved_errno) {
    case EACCES:
    case EISDIR:
    case EROFS:
    case EPERM:
      return FILE_ERROR_ACCESS_DENIED;
#if !defined(OS_NACL)  // ETXTBSY not defined by NaCl.
    case ETXTBSY:
      return FILE_ERROR_IN_USE;
#endif
    case EEXIST:
      return FILE_ERROR_EXISTS;
    case ENOENT:
      return FILE_ERROR_NOT_FOUND;
    case EMFILE:
      return FILE_ERROR_TOO_MANY_OPENED;
    case ENOMEM:
      return FILE_ERROR_NO_MEMORY;
    case ENOSPC:
      return FILE_ERROR_NO_SPACE;
    case ENOTDIR:
      return 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 FILE_ERROR_FAILED;
  }
}

void File::SetPlatformFile(PlatformFile file) {
  DCHECK(!file_.is_valid());
  file_.reset(file);
}

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

DEFINITIONS
