Revert of Make SharedMemoryHandle a class on Mac.

base/memory/shared_memory_mac.cc

Index: base/memory/shared_memory_mac.cc
diff --git a/base/memory/shared_memory_mac.cc b/base/memory/shared_memory_mac.cc
deleted file mode 100644
index 0ec8b8544fa5c3abc19ea639868126cc3030c536..0000000000000000000000000000000000000000
--- a/base/memory/shared_memory_mac.cc
+++ /dev/null
@@ -1,464 +0,0 @@
-// 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/memory/shared_memory.h"
-
-#include <fcntl.h>
-#include <sys/mman.h>
-#include <sys/stat.h>
-#include <unistd.h>
-
-#include "base/files/file_util.h"
-#include "base/files/scoped_file.h"
-#include "base/logging.h"
-#include "base/posix/eintr_wrapper.h"
-#include "base/posix/safe_strerror.h"
-#include "base/process/process_metrics.h"
-#include "base/profiler/scoped_tracker.h"
-#include "base/scoped_generic.h"
-#include "base/strings/utf_string_conversions.h"
-
-#if defined(OS_MACOSX)
-#include "base/mac/foundation_util.h"
-#endif  // OS_MACOSX
-
-namespace base {
-
-namespace {
-
-struct ScopedPathUnlinkerTraits {
-  static FilePath* InvalidValue() { return nullptr; }
-
-  static void Free(FilePath* path) {
-    // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466437
-    // is fixed.
-    tracked_objects::ScopedTracker tracking_profile(
-        FROM_HERE_WITH_EXPLICIT_FUNCTION(
-            "466437 SharedMemory::Create::Unlink"));
-    if (unlink(path->value().c_str()))
-      PLOG(WARNING) << "unlink";
-  }
-};
-
-// Unlinks the FilePath when the object is destroyed.
-typedef ScopedGeneric<FilePath*, ScopedPathUnlinkerTraits> ScopedPathUnlinker;
-
-// Makes a temporary file, fdopens it, and then unlinks it. |fp| is populated
-// with the fdopened FILE. |readonly_fd| is populated with the opened fd if
-// options.share_read_only is true. |path| is populated with the location of
-// the file before it was unlinked.
-// Returns false if there's an unhandled failure.
-bool CreateAnonymousSharedMemory(const SharedMemoryCreateOptions& options,
-                                 ScopedFILE* fp,
-                                 ScopedFD* readonly_fd,
-                                 FilePath* path) {
-  // It doesn't make sense to have a open-existing private piece of shmem
-  DCHECK(!options.open_existing_deprecated);
-  // Q: Why not use the shm_open() etc. APIs?
-  // A: Because they're limited to 4mb on OS X.  FFFFFFFUUUUUUUUUUU
-  FilePath directory;
-  ScopedPathUnlinker path_unlinker;
-  if (GetShmemTempDir(options.executable, &directory)) {
-    // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466437
-    // is fixed.
-    tracked_objects::ScopedTracker tracking_profile(
-        FROM_HERE_WITH_EXPLICIT_FUNCTION(
-            "466437 SharedMemory::Create::OpenTemporaryFile"));
-    fp->reset(base::CreateAndOpenTemporaryFileInDir(directory, path));
-
-    // Deleting the file prevents anyone else from mapping it in (making it
-    // private), and prevents the need for cleanup (once the last fd is
-    // closed, it is truly freed).
-    if (*fp)
-      path_unlinker.reset(path);
-  }
-
-  if (*fp) {
-    if (options.share_read_only) {
-      // TODO(erikchen): Remove ScopedTracker below once
-      // http://crbug.com/466437 is fixed.
-      tracked_objects::ScopedTracker tracking_profile(
-          FROM_HERE_WITH_EXPLICIT_FUNCTION(
-              "466437 SharedMemory::Create::OpenReadonly"));
-      // Also open as readonly so that we can ShareReadOnlyToProcess.
-      readonly_fd->reset(HANDLE_EINTR(open(path->value().c_str(), O_RDONLY)));
-      if (!readonly_fd->is_valid()) {
-        DPLOG(ERROR) << "open(\"" << path->value() << "\", O_RDONLY) failed";
-        fp->reset();
-        return false;
-      }
-    }
-  }
-  return true;
-}
-}
-
-SharedMemory::SharedMemory()
-    : mapped_file_(-1),
-      readonly_mapped_file_(-1),
-      mapped_size_(0),
-      memory_(NULL),
-      read_only_(false),
-      requested_size_(0) {
-}
-
-SharedMemory::SharedMemory(const SharedMemoryHandle& handle, bool read_only)
-    : mapped_file_(GetFdFromSharedMemoryHandle(handle)),
-      readonly_mapped_file_(-1),
-      mapped_size_(0),
-      memory_(NULL),
-      read_only_(read_only),
-      requested_size_(0) {
-}
-
-SharedMemory::SharedMemory(const SharedMemoryHandle& handle,
-                           bool read_only,
-                           ProcessHandle process)
-    : mapped_file_(GetFdFromSharedMemoryHandle(handle)),
-      readonly_mapped_file_(-1),
-      mapped_size_(0),
-      memory_(NULL),
-      read_only_(read_only),
-      requested_size_(0) {
-  // We don't handle this case yet (note the ignored parameter); let's die if
-  // someone comes calling.
-  NOTREACHED();
-}
-
-SharedMemory::~SharedMemory() {
-  Unmap();
-  Close();
-}
-
-// static
-bool SharedMemory::IsHandleValid(const SharedMemoryHandle& handle) {
-  return handle.IsValid();
-}
-
-// static
-SharedMemoryHandle SharedMemory::NULLHandle() {
-  return SharedMemoryHandle();
-}
-
-// static
-void SharedMemory::CloseHandle(const SharedMemoryHandle& handle) {
-  DCHECK_GE(GetFdFromSharedMemoryHandle(handle), 0);
-  if (close(GetFdFromSharedMemoryHandle(handle)) < 0)
-    DPLOG(ERROR) << "close";
-}
-
-// static
-size_t SharedMemory::GetHandleLimit() {
-  return base::GetMaxFds();
-}
-
-// static
-SharedMemoryHandle SharedMemory::DuplicateHandle(
-    const SharedMemoryHandle& handle) {
-  return handle.Duplicate();
-}
-
-// static
-int SharedMemory::GetFdFromSharedMemoryHandle(
-    const SharedMemoryHandle& handle) {
-  return handle.GetFileDescriptor().fd;
-}
-
-bool SharedMemory::CreateAndMapAnonymous(size_t size) {
-  return CreateAnonymous(size) && Map(size);
-}
-
-// static
-int SharedMemory::GetSizeFromSharedMemoryHandle(
-    const SharedMemoryHandle& handle) {
-  struct stat st;
-  if (fstat(GetFdFromSharedMemoryHandle(handle), &st) != 0)
-    return -1;
-  return st.st_size;
-}
-
-// Chromium mostly only uses the unique/private shmem as specified by
-// "name == L"". The exception is in the StatsTable.
-// TODO(jrg): there is no way to "clean up" all unused named shmem if
-// we restart from a crash.  (That isn't a new problem, but it is a problem.)
-// In case we want to delete it later, it may be useful to save the value
-// of mem_filename after FilePathForMemoryName().
-bool SharedMemory::Create(const SharedMemoryCreateOptions& options) {
-  // TODO(erikchen): Remove ScopedTracker below once http://crbug.com/466437
-  // is fixed.
-  tracked_objects::ScopedTracker tracking_profile1(
-      FROM_HERE_WITH_EXPLICIT_FUNCTION(
-          "466437 SharedMemory::Create::Start"));
-  DCHECK_EQ(-1, mapped_file_);
-  if (options.size == 0) return false;
-
-  if (options.size > static_cast<size_t>(std::numeric_limits<int>::max()))
-    return false;
-
-  // This function theoretically can block on the disk, but realistically
-  // the temporary files we create will just go into the buffer cache
-  // and be deleted before they ever make it out to disk.
-  base::ThreadRestrictions::ScopedAllowIO allow_io;
-
-  ScopedFILE fp;
-  bool fix_size = true;
-  ScopedFD readonly_fd;
-
-  FilePath path;
-  if (options.name_deprecated == NULL || options.name_deprecated->empty()) {
-    bool result =
-        CreateAnonymousSharedMemory(options, &fp, &readonly_fd, &path);
-    if (!result)
-      return false;
-  } else {
-    if (!FilePathForMemoryName(*options.name_deprecated, &path))
-      return false;
-
-    // Make sure that the file is opened without any permission
-    // to other users on the system.
-    const mode_t kOwnerOnly = S_IRUSR | S_IWUSR;
-
-    // First, try to create the file.
-    int fd = HANDLE_EINTR(
-        open(path.value().c_str(), O_RDWR | O_CREAT | O_EXCL, kOwnerOnly));
-    if (fd == -1 && options.open_existing_deprecated) {
-      // If this doesn't work, try and open an existing file in append mode.
-      // Opening an existing file in a world writable directory has two main
-      // security implications:
-      // - Attackers could plant a file under their control, so ownership of
-      //   the file is checked below.
-      // - Attackers could plant a symbolic link so that an unexpected file
-      //   is opened, so O_NOFOLLOW is passed to open().
-      fd = HANDLE_EINTR(
-          open(path.value().c_str(), O_RDWR | O_APPEND | O_NOFOLLOW));
-
-      // Check that the current user owns the file.
-      // If uid != euid, then a more complex permission model is used and this
-      // API is not appropriate.
-      const uid_t real_uid = getuid();
-      const uid_t effective_uid = geteuid();
-      struct stat sb;
-      if (fd >= 0 &&
-          (fstat(fd, &sb) != 0 || sb.st_uid != real_uid ||
-           sb.st_uid != effective_uid)) {
-        LOG(ERROR) <<
-            "Invalid owner when opening existing shared memory file.";
-        close(fd);
-        return false;
-      }
-
-      // An existing file was opened, so its size should not be fixed.
-      fix_size = false;
-    }
-
-    if (options.share_read_only) {
-      // Also open as readonly so that we can ShareReadOnlyToProcess.
-      readonly_fd.reset(HANDLE_EINTR(open(path.value().c_str(), O_RDONLY)));
-      if (!readonly_fd.is_valid()) {
-        DPLOG(ERROR) << "open(\"" << path.value() << "\", O_RDONLY) failed";
-        close(fd);
-        fd = -1;
-        return false;
-      }
-    }
-    if (fd >= 0) {
-      // "a+" is always appropriate: if it's a new file, a+ is similar to w+.
-      fp.reset(fdopen(fd, "a+"));
-    }
-  }
-  if (fp && fix_size) {
-    // Get current size.
-    struct stat stat;
-    if (fstat(fileno(fp.get()), &stat) != 0)
-      return false;
-    const size_t current_size = stat.st_size;
-    if (current_size != options.size) {
-      if (HANDLE_EINTR(ftruncate(fileno(fp.get()), options.size)) != 0)
-        return false;
-    }
-    requested_size_ = options.size;
-  }
-  if (fp == NULL) {
-    PLOG(ERROR) << "Creating shared memory in " << path.value() << " failed";
-    return false;
-  }
-
-  return PrepareMapFile(fp.Pass(), readonly_fd.Pass());
-}
-
-// Our current implementation of shmem is with mmap()ing of files.
-// These files need to be deleted explicitly.
-// In practice this call is only needed for unit tests.
-bool SharedMemory::Delete(const std::string& name) {
-  FilePath path;
-  if (!FilePathForMemoryName(name, &path))
-    return false;
-
-  if (PathExists(path))
-    return base::DeleteFile(path, false);
-
-  // Doesn't exist, so success.
-  return true;
-}
-
-bool SharedMemory::Open(const std::string& name, bool read_only) {
-  FilePath path;
-  if (!FilePathForMemoryName(name, &path))
-    return false;
-
-  read_only_ = read_only;
-
-  const char *mode = read_only ? "r" : "r+";
-  ScopedFILE fp(base::OpenFile(path, mode));
-  ScopedFD readonly_fd(HANDLE_EINTR(open(path.value().c_str(), O_RDONLY)));
-  if (!readonly_fd.is_valid()) {
-    DPLOG(ERROR) << "open(\"" << path.value() << "\", O_RDONLY) failed";
-    return false;
-  }
-  return PrepareMapFile(fp.Pass(), readonly_fd.Pass());
-}
-
-bool SharedMemory::MapAt(off_t offset, size_t bytes) {
-  if (mapped_file_ == -1)
-    return false;
-
-  if (bytes > static_cast<size_t>(std::numeric_limits<int>::max()))
-    return false;
-
-  if (memory_)
-    return false;
-
-  memory_ = mmap(NULL, bytes, PROT_READ | (read_only_ ? 0 : PROT_WRITE),
-                 MAP_SHARED, mapped_file_, offset);
-
-  bool mmap_succeeded = memory_ != (void*)-1 && memory_ != NULL;
-  if (mmap_succeeded) {
-    mapped_size_ = bytes;
-    DCHECK_EQ(0U, reinterpret_cast<uintptr_t>(memory_) &
-        (SharedMemory::MAP_MINIMUM_ALIGNMENT - 1));
-  } else {
-    memory_ = NULL;
-  }
-
-  return mmap_succeeded;
-}
-
-bool SharedMemory::Unmap() {
-  if (memory_ == NULL)
-    return false;
-
-  munmap(memory_, mapped_size_);
-  memory_ = NULL;
-  mapped_size_ = 0;
-  return true;
-}
-
-SharedMemoryHandle SharedMemory::handle() const {
-  return SharedMemoryHandle(mapped_file_, false);
-}
-
-void SharedMemory::Close() {
-  if (mapped_file_ > 0) {
-    if (close(mapped_file_) < 0)
-      PLOG(ERROR) << "close";
-    mapped_file_ = -1;
-  }
-  if (readonly_mapped_file_ > 0) {
-    if (close(readonly_mapped_file_) < 0)
-      PLOG(ERROR) << "close";
-    readonly_mapped_file_ = -1;
-  }
-}
-
-bool SharedMemory::PrepareMapFile(ScopedFILE fp, ScopedFD readonly_fd) {
-  DCHECK_EQ(-1, mapped_file_);
-  DCHECK_EQ(-1, readonly_mapped_file_);
-  if (fp == NULL)
-    return false;
-
-  // This function theoretically can block on the disk, but realistically
-  // the temporary files we create will just go into the buffer cache
-  // and be deleted before they ever make it out to disk.
-  base::ThreadRestrictions::ScopedAllowIO allow_io;
-
-  struct stat st = {};
-  if (fstat(fileno(fp.get()), &st))
-    NOTREACHED();
-  if (readonly_fd.is_valid()) {
-    struct stat readonly_st = {};
-    if (fstat(readonly_fd.get(), &readonly_st))
-      NOTREACHED();
-    if (st.st_dev != readonly_st.st_dev || st.st_ino != readonly_st.st_ino) {
-      LOG(ERROR) << "writable and read-only inodes don't match; bailing";
-      return false;
-    }
-  }
-
-  mapped_file_ = HANDLE_EINTR(dup(fileno(fp.get())));
-  if (mapped_file_ == -1) {
-    if (errno == EMFILE) {
-      LOG(WARNING) << "Shared memory creation failed; out of file descriptors";
-      return false;
-    } else {
-      NOTREACHED() << "Call to dup failed, errno=" << errno;
-    }
-  }
-  readonly_mapped_file_ = readonly_fd.release();
-
-  return true;
-}
-
-// For the given shmem named |mem_name|, return a filename to mmap()
-// (and possibly create).  Modifies |filename|.  Return false on
-// error, or true of we are happy.
-bool SharedMemory::FilePathForMemoryName(const std::string& mem_name,
-                                         FilePath* path) {
-  // mem_name will be used for a filename; make sure it doesn't
-  // contain anything which will confuse us.
-  DCHECK_EQ(std::string::npos, mem_name.find('/'));
-  DCHECK_EQ(std::string::npos, mem_name.find('\0'));
-
-  FilePath temp_dir;
-  if (!GetShmemTempDir(false, &temp_dir))
-    return false;
-
-  std::string name_base = std::string(base::mac::BaseBundleID());
-  *path = temp_dir.AppendASCII(name_base + ".shmem." + mem_name);
-  return true;
-}
-
-bool SharedMemory::ShareToProcessCommon(ProcessHandle process,
-                                        SharedMemoryHandle* new_handle,
-                                        bool close_self,
-                                        ShareMode share_mode) {
-  int handle_to_dup = -1;
-  switch(share_mode) {
-    case SHARE_CURRENT_MODE:
-      handle_to_dup = mapped_file_;
-      break;
-    case SHARE_READONLY:
-      // We could imagine re-opening the file from /dev/fd, but that can't make
-      // it readonly on Mac: https://codereview.chromium.org/27265002/#msg10
-      CHECK_GE(readonly_mapped_file_, 0);
-      handle_to_dup = readonly_mapped_file_;
-      break;
-  }
-
-  const int new_fd = HANDLE_EINTR(dup(handle_to_dup));
-  if (new_fd < 0) {
-    DPLOG(ERROR) << "dup() failed.";
-    return false;
-  }
-
-  new_handle->SetFileHandle(new_fd, true);
-
-  if (close_self) {
-    Unmap();
-    Close();
-  }
-
-  return true;
-}
-
-}  // namespace base