Split the IPC code into ipc/

This splits the ipc code from the common project.  The 'common' project pulls in
all of webkit, the v8 bindings, skia, googleurl, and a number of other projects
which makes it very difficult to deal with especially for external projects
wanting just to use some of Chromium's infrastructure.  This puts the ipc code
into its top-level ipc/ directory with a dependency only on base.  The common
project depends on the new ipc/ipc.gyp:ipc target so that all projects currently
pulling common in to get the IPC code still have it available.  This mostly
follows agl's pre-gyp attempt to do this which was r13062.

Known issues:
- Currently a number of projects depend on chrome/chrome.gyp:common in order to
use the IPC infrastructure.  Rather than fixing all of these dependencies I have
made common depend on ipc/ipc.gyp:ipc and added "ipc" to the include_rules
section of DEPS so that checkdeps.py doesn't complain.  Over time projects that
need IPC should depend on the IPC project themselves and dependencies on common
removed, although I don't think many projects that need IPC will be able to get
away without common currently.
- ipc/ipc_message_macros.h still has #include "chrome/common/..." inside of a
ipc/ should not refer to files in chrome/... now.  I'm not sure how to resolve
this since it's really an IDE bug
- the named pipe name (windows+linux) and the logging event name (all) + env
variable (posix) refer explicitly to 'Chrome' which somewhat hurts the illusion
of ipc/ being an independent library.  I think this should be examined in a
subsequent, much smaller patch.
- I've eliminated the IPC.SendMsgCount counter since it was implemented in a way
to create a dependency from ipc/ to chrome/common/chrome_counters. This is the
same approach that r13062 took.

http://codereview.chromium.org/155905

(Patch from James Robinson)


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@21342 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 119 insertions, 0 deletions

diff --git a/ipc/file_descriptor_set_posix.cc b/ipc/file_descriptor_set_posix.cc
new file mode 100644
index 0000000..519e6e7
--- /dev/null
+++ b/ipc/file_descriptor_set_posix.cc
@@ -0,0 +1,119 @@
+// 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 "ipc/file_descriptor_set_posix.h"
+
+#include "base/eintr_wrapper.h"
+#include "base/logging.h"
+
+FileDescriptorSet::FileDescriptorSet()
+    : consumed_descriptor_highwater_(0) {
+}
+
+FileDescriptorSet::~FileDescriptorSet() {
+  if (consumed_descriptor_highwater_ == descriptors_.size())
+    return;
+
+  LOG(WARNING) << "FileDescriptorSet 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 rogue renderer) then all
+  // the descriptors have their close flag set and we free all the extra
+  // kernel resources.
+  for (unsigned i = consumed_descriptor_highwater_;
+       i < descriptors_.size(); ++i) {
+    if (descriptors_[i].auto_close)
+      HANDLE_EINTR(close(descriptors_[i].fd));
+  }
+}
+
+bool FileDescriptorSet::Add(int fd) {
+  if (descriptors_.size() == MAX_DESCRIPTORS_PER_MESSAGE)
+    return false;
+
+  struct base::FileDescriptor sd;
+  sd.fd = fd;
+  sd.auto_close = false;
+  descriptors_.push_back(sd);
+  return true;
+}
+
+bool FileDescriptorSet::AddAndAutoClose(int fd) {
+  if (descriptors_.size() == MAX_DESCRIPTORS_PER_MESSAGE)
+    return false;
+
+  struct base::FileDescriptor sd;
+  sd.fd = fd;
+  sd.auto_close = true;
+  descriptors_.push_back(sd);
+  DCHECK(descriptors_.size() <= MAX_DESCRIPTORS_PER_MESSAGE);
+  return true;
+}
+
+int FileDescriptorSet::GetDescriptorAt(unsigned index) const {
+  if (index >= descriptors_.size())
+    return -1;
+
+  // We should always walk the descriptors in order, so it's reasonable to
+  // enforce this. Consider the case where a compromised renderer sends us
+  // the following message:
+  //
+  //   ExampleMsg:
+  //     num_fds:2 msg:FD(index = 1) control:SCM_RIGHTS {n, m}
+  //
+  // Here the renderer sent us a message which should have a descriptor, but
+  // actually sent two in an attempt to fill our fd table and kill us. By
+  // setting the index of the descriptor in the message to 1 (it should be
+  // 0), we would record a highwater of 1 and then consider all the
+  // descriptors to have been used.
+  //
+  // So we can either track of the use of each descriptor in a bitset, or we
+  // can enforce that we walk the indexes strictly in order.
+  //
+  // There's one more wrinkle: When logging messages, we may reparse them. So
+  // we have an exception: When the consumed_descriptor_highwater_ is at the
+  // end of the array and index 0 is requested, we reset the highwater value.
+  if (index == 0 && consumed_descriptor_highwater_ == descriptors_.size())
+    consumed_descriptor_highwater_ = 0;
+
+  if (index != consumed_descriptor_highwater_)
+    return -1;
+
+  consumed_descriptor_highwater_ = index + 1;
+  return descriptors_[index].fd;
+}
+
+void FileDescriptorSet::GetDescriptors(int* buffer) const {
+  for (std::vector<base::FileDescriptor>::const_iterator
+       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
+    *(buffer++) = i->fd;
+  }
+}
+
+void FileDescriptorSet::CommitAll() {
+  for (std::vector<base::FileDescriptor>::iterator
+       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
+    if (i->auto_close)
+      HANDLE_EINTR(close(i->fd));
+  }
+  descriptors_.clear();
+  consumed_descriptor_highwater_ = 0;
+}
+
+void FileDescriptorSet::SetDescriptors(const int* buffer, unsigned count) {
+  DCHECK_LE(count, MAX_DESCRIPTORS_PER_MESSAGE);
+  DCHECK_EQ(descriptors_.size(), 0u);
+  DCHECK_EQ(consumed_descriptor_highwater_, 0u);
+
+  descriptors_.reserve(count);
+  for (unsigned i = 0; i < count; ++i) {
+    struct base::FileDescriptor sd;
+    sd.fd = buffer[i];
+    sd.auto_close = true;
+    descriptors_.push_back(sd);
+  }
+}