POSIX: Transfer network data using shared memory

chrome/common/file_descriptor_posix.cc

-// Copyright (c) 2006-2008 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 "chrome/common/file_descriptor_posix.h"
-
-#include "base/logging.h"
-
-DescriptorSet::DescriptorSet()
-    : next_descriptor_(0) {
-}
-
-DescriptorSet::~DescriptorSet() {
-  if (next_descriptor_ == descriptors_.size())
-    return;
-
-  LOG(WARNING) << "DescriptorSet destroyed with unconsumed descriptors";
-  // We close all the descriptors where the close flag is set. If this
-  // message should have been transmitted, then closing those with close
-  // flags set mirrors the expected behaviour.
-  //
-  // If this message was received with more descriptors than expected
-  // (which could a DOS against the browser by a rouge renderer) then all
-  // the descriptors have their close flag set and we free all the extra
-  // kernel resources.
-  for (unsigned i = next_descriptor_; i < descriptors_.size(); ++i) {
-    if (descriptors_[i].auto_close)
-      close(descriptors_[i].fd);
-  }
-}
-
-void DescriptorSet::Add(int fd) {
-  struct FileDescriptor sd;
-  sd.fd = fd;
-  sd.auto_close = false;
-  descriptors_.push_back(sd);
-  DCHECK(descriptors_.size() <= MAX_DESCRIPTORS_PER_MESSAGE);
-}
-
-void DescriptorSet::AddAndAutoClose(int fd) {
-  struct FileDescriptor sd;
-  sd.fd = fd;
-  sd.auto_close = true;
-  descriptors_.push_back(sd);
-  DCHECK(descriptors_.size() <= MAX_DESCRIPTORS_PER_MESSAGE);
-}
-
-int DescriptorSet::NextDescriptor() {
-  if (next_descriptor_ == descriptors_.size())
-    return -1;
-
-  return descriptors_[next_descriptor_++].fd;
-}
-
-void DescriptorSet::GetDescriptors(int* buffer) const {
-  for (std::vector<FileDescriptor>::const_iterator
-       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
-    *(buffer++) = i->fd;
-  }
-}
-
-void DescriptorSet::CommitAll() {
-  for (std::vector<FileDescriptor>::iterator
-       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
-    if (i->auto_close)
-      close(i->fd);
-  }
-  descriptors_.clear();
-}
-
-void DescriptorSet::SetDescriptors(const int* buffer, unsigned count) {
-  DCHECK(count <= MAX_DESCRIPTORS_PER_MESSAGE);
-  DCHECK(descriptors_.size() == 0);
-
-  descriptors_.reserve(count);
-  for (unsigned i = 0; i < count; ++i) {
-    struct FileDescriptor sd;
-    sd.fd = buffer[i];
-    sd.auto_close = true;
-    descriptors_.push_back(sd);
-  }
-}
-
-void DescriptorSet::TakeFrom(DescriptorSet* other) {
-  DCHECK(descriptors_.size() == 0);
-
-  descriptors_.swap(other->descriptors_);
-  next_descriptor_ = other->next_descriptor_;
-  other->next_descriptor_ = 0;
-}