1 files changed, 273 insertions, 0 deletions
diff --git a/remoting/host/policy_hack/nat_policy_linux.cc b/remoting/host/policy_hack/nat_policy_linux.cc
new file mode 100644
index 0000000..6037ddc
--- /dev/null
+++ b/remoting/host/policy_hack/nat_policy_linux.cc
@@ -0,0 +1,273 @@
+// 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.
+
+// Most of this code is copied from various classes in
+// src/chrome/browser/policy. In particular, look at
+//
+//   file_based_policy_loader.{h,cc}
+//   config_dir_policy_provider.{h,cc}
+//
+// This is a reduction of the functionality in those classes.
+
+#include <set>
+
+#include "remoting/host/policy_hack/nat_policy.h"
+
+#include "base/bind.h"
+#include "base/compiler_specific.h"
+#include "base/file_path.h"
+#include "base/file_util.h"
+#include "base/files/file_path_watcher.h"
+#include "base/json/json_value_serializer.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/memory/weak_ptr.h"
+#include "base/message_loop_proxy.h"
+#include "base/synchronization/waitable_event.h"
+#include "base/time.h"
+#include "base/values.h"
+
+namespace remoting {
+namespace policy_hack {
+
+namespace {
+
+const FilePath::CharType kPolicyDir[] =
+    FILE_PATH_LITERAL("/etc/opt/chrome/policies/managed");
+
+// Amount of time we wait for the files on disk to settle before trying to load
+// them. This alleviates the problem of reading partially written files and
+// makes it possible to batch quasi-simultaneous changes.
+const int kSettleIntervalSeconds = 5;
+
+}  // namespace
+
+class NatPolicyLinux : public NatPolicy {
+ public:
+  NatPolicyLinux(base::MessageLoopProxy* message_loop_proxy,
+                 const FilePath& config_dir)
+      : NatPolicy(message_loop_proxy),
+        config_dir_(config_dir),
+        ALLOW_THIS_IN_INITIALIZER_LIST(weak_factory_(this)) {
+    // Detach the factory because we ensure that only the policy thread ever
+    // calls methods on this. Also, the API contract of having to call
+    // StopWatching() (which signals completion) after StartWatching()
+    // before this object can be destructed ensures there are no users of
+    // this object before it is destructed.
+    weak_factory_.DetachFromThread();
+  }
+
+  virtual ~NatPolicyLinux() {}
+
+ protected:
+  virtual void StartWatchingInternal() OVERRIDE {
+    DCHECK(OnPolicyThread());
+    watcher_.reset(new base::files::FilePathWatcher());
+
+    if (!config_dir_.empty() &&
+        !watcher_->Watch(
+            config_dir_,
+            new FilePathWatcherDelegate(weak_factory_.GetWeakPtr()))) {
+      OnFilePathError(config_dir_);
+    }
+
+    // There might have been changes to the directory in the time between
+    // construction of the loader and initialization of the watcher. Call reload
+    // to detect if that is the case.
+    Reload();
+
+    ScheduleFallbackReloadTask();
+  }
+
+  virtual void StopWatchingInternal() OVERRIDE {
+    DCHECK(OnPolicyThread());
+    // Cancel any inflight requests.
+    watcher_.reset();
+  }
+
+  // Called by FilePathWatcherDelegate.
+  virtual void OnFilePathError(const FilePath& path) {
+    LOG(ERROR) << "NatPolicyLinux on " << path.value()
+               << " failed.";
+  }
+
+  // Called by FilePathWatcherDelegate.
+  virtual void OnFilePathChanged(const FilePath& path) {
+    DCHECK(OnPolicyThread());
+
+    Reload();
+  }
+
+ private:
+  // Needed to avoid refcounting NatPolicyLinux.
+  class FilePathWatcherDelegate :
+    public base::files::FilePathWatcher::Delegate {
+   public:
+    FilePathWatcherDelegate(base::WeakPtr<NatPolicyLinux> policy_watcher)
+        : policy_watcher_(policy_watcher) {
+    }
+
+    virtual void OnFilePathError(const FilePath& path) {
+      if (policy_watcher_) {
+        policy_watcher_->OnFilePathError(path);
+      }
+    }
+
+    virtual void OnFilePathChanged(const FilePath& path) {
+      if (policy_watcher_) {
+        policy_watcher_->OnFilePathChanged(path);
+      }
+    }
+
+   private:
+    base::WeakPtr<NatPolicyLinux> policy_watcher_;
+  };
+
+  base::Time GetLastModification() {
+    DCHECK(OnPolicyThread());
+    base::Time last_modification = base::Time();
+    base::PlatformFileInfo file_info;
+
+    // If the path does not exist or points to a directory, it's safe to load.
+    if (!file_util::GetFileInfo(config_dir_, &file_info) ||
+        !file_info.is_directory) {
+      return last_modification;
+    }
+
+    // Enumerate the files and find the most recent modification timestamp.
+    file_util::FileEnumerator file_enumerator(config_dir_,
+                                              false,
+                                              file_util::FileEnumerator::FILES);
+    for (FilePath config_file = file_enumerator.Next();
+         !config_file.empty();
+         config_file = file_enumerator.Next()) {
+      if (file_util::GetFileInfo(config_file, &file_info) &&
+          !file_info.is_directory) {
+        last_modification = std::max(last_modification,
+                                     file_info.last_modified);
+      }
+    }
+
+    return last_modification;
+  }
+
+  // Caller owns the value.
+  DictionaryValue* Load() {
+    DCHECK(OnPolicyThread());
+    // Enumerate the files and sort them lexicographically.
+    std::set<FilePath> files;
+    file_util::FileEnumerator file_enumerator(config_dir_, false,
+                                              file_util::FileEnumerator::FILES);
+    for (FilePath config_file_path = file_enumerator.Next();
+         !config_file_path.empty(); config_file_path = file_enumerator.Next())
+      files.insert(config_file_path);
+
+    // Start with an empty dictionary and merge the files' contents.
+    DictionaryValue* policy = new DictionaryValue();
+    for (std::set<FilePath>::iterator config_file_iter = files.begin();
+         config_file_iter != files.end(); ++config_file_iter) {
+      JSONFileValueSerializer deserializer(*config_file_iter);
+      int error_code = 0;
+      std::string error_msg;
+      scoped_ptr<Value> value(
+          deserializer.Deserialize(&error_code, &error_msg));
+      if (!value.get()) {
+        LOG(WARNING) << "Failed to read configuration file "
+                     << config_file_iter->value() << ": " << error_msg;
+        continue;
+      }
+      if (!value->IsType(Value::TYPE_DICTIONARY)) {
+        LOG(WARNING) << "Expected JSON dictionary in configuration file "
+                     << config_file_iter->value();
+        continue;
+      }
+      policy->MergeDictionary(static_cast<DictionaryValue*>(value.get()));
+    }
+
+    return policy;
+  }
+
+  void Reload() {
+    DCHECK(OnPolicyThread());
+    // Check the directory time in order to see whether a reload is required.
+    base::TimeDelta delay;
+    base::Time now = base::Time::Now();
+    if (!IsSafeToReloadPolicy(now, &delay)) {
+      ScheduleReloadTask(delay);
+      return;
+    }
+
+    // Check again in case the directory has changed while reading it.
+    if (!IsSafeToReloadPolicy(now, &delay)) {
+      ScheduleReloadTask(delay);
+      return;
+    }
+
+    // Load the policy definitions.
+    scoped_ptr<DictionaryValue> new_policy(Load());
+    UpdateNatPolicy(new_policy.get());
+
+    ScheduleFallbackReloadTask();
+  }
+
+  bool IsSafeToReloadPolicy(const base::Time& now, base::TimeDelta* delay) {
+    DCHECK(OnPolicyThread());
+    DCHECK(delay);
+    const base::TimeDelta kSettleInterval =
+        base::TimeDelta::FromSeconds(kSettleIntervalSeconds);
+
+    base::Time last_modification = GetLastModification();
+    if (last_modification.is_null())
+      return true;
+
+    if (last_modification_file_.is_null())
+      last_modification_file_ = last_modification;
+
+    // If there was a change since the last recorded modification, wait some
+    // more.
+    if (last_modification != last_modification_file_) {
+      last_modification_file_ = last_modification;
+      last_modification_clock_ = now;
+      *delay = kSettleInterval;
+      return false;
+    }
+
+    // Check whether the settle interval has elapsed.
+    base::TimeDelta age = now - last_modification_clock_;
+    if (age < kSettleInterval) {
+      *delay = kSettleInterval - age;
+      return false;
+    }
+
+    return true;
+  }
+
+  // Managed with a scoped_ptr rather than being declared as an inline member to
+  // decouple the watcher's life cycle from the NatPolicyLinux. This decoupling
+  // makes it possible to destroy the watcher before the loader's destructor is
+  // called (e.g. during Stop), since |watcher_| internally holds a reference to
+  // the loader and keeps it alive.
+  scoped_ptr<base::files::FilePathWatcher> watcher_;
+
+  // Records last known modification timestamp of |config_dir_|.
+  base::Time last_modification_file_;
+
+  // The wall clock time at which the last modification timestamp was
+  // recorded.  It's better to not assume the file notification time and the
+  // wall clock times come from the same source, just in case there is some
+  // non-local filesystem involved.
+  base::Time last_modification_clock_;
+
+  const FilePath config_dir_;
+
+  // Allows us to cancel any inflight FileWatcher events or scheduled reloads.
+  base::WeakPtrFactory<NatPolicyLinux> weak_factory_;
+};
+
+NatPolicy* NatPolicy::Create(base::MessageLoopProxy* message_loop_proxy) {
+  FilePath policy_dir(kPolicyDir);
+  return new NatPolicyLinux(message_loop_proxy, policy_dir);
+}
+
+}  // namespace policy_hack
+}  // namespace remoting