Linux: refactor zygote support

http://code.google.com/p/chromium/wiki/LinuxZygote

  * Move Chrome specific bits out of base
  * Move away from the idea of reserved file descriptors (which don't really work
  with zygotes)
  * Load resources before forking renderers (means that we don't need
  communication between the zygote process and the renderers)
  * Make sure that gdb works against the browser again
  * Make sure that we have different ASLR between the renderers and the browser.

http://codereview.chromium.org/119335

(This is a reland. First landed in r18109, reverted in r18112.)


git-svn-id: svn://svn.chromium.org/chrome/trunk/src@18291 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 46 insertions, 0 deletions

diff --git a/base/global_descriptors_posix.cc b/base/global_descriptors_posix.cc
new file mode 100644
index 0000000..869d196
--- /dev/null
+++ b/base/global_descriptors_posix.cc
@@ -0,0 +1,46 @@
+// Copyright (c) 2009 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/global_descriptors_posix.h"
+
+#include <vector>
+#include <utility>
+
+#include "base/logging.h"
+
+namespace base {
+
+int GlobalDescriptors::MaybeGet(Key key) const {
+  for (Mapping::const_iterator
+       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
+    if (i->first == key)
+      return i->second;
+  }
+
+  // In order to make unittests pass, we define a default mapping from keys to
+  // descriptors by adding a fixed offset:
+  return kBaseDescriptor + key;
+}
+
+int GlobalDescriptors::Get(Key key) const {
+  const int ret = MaybeGet(key);
+
+  if (ret == -1)
+    LOG(FATAL) << "Unknown global descriptor: " << key;
+  return ret;
+}
+
+void GlobalDescriptors::Set(Key key, int fd) {
+  for (Mapping::iterator
+       i = descriptors_.begin(); i != descriptors_.end(); ++i) {
+    if (i->first == key) {
+      i->second = fd;
+      return;
+    }
+  }
+
+  descriptors_.push_back(std::make_pair(key, fd));
+}
+
+}  // namespace base