ppapi/proxy/host_dispatcher.cc

   1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "ppapi/proxy/host_dispatcher.h"
   6
   7 #include "base/debug/trace_event.h"
   8 #include "base/logging.h"
   9 #include "ppapi/c/private/ppb_proxy_private.h"
  10 #include "ppapi/c/ppb_var.h"
  11 #include "ppapi/proxy/host_var_serialization_rules.h"
  12 #include "ppapi/proxy/interface_list.h"
  13 #include "ppapi/proxy/ppapi_messages.h"
  14 #include "ppapi/proxy/resource_creation_proxy.h"
  15 #include "ppapi/shared_impl/ppapi_globals.h"
  16
  17 namespace ppapi {
  18 namespace proxy {
  19
  20 namespace {
  21
  22 typedef std::map<PP_Instance, HostDispatcher*> InstanceToDispatcherMap;
  23 InstanceToDispatcherMap* g_instance_to_dispatcher = NULL;
  24
  25 typedef std::map<PP_Module, HostDispatcher*> ModuleToDispatcherMap;
  26 ModuleToDispatcherMap* g_module_to_dispatcher = NULL;
  27
  28 PP_Bool ReserveInstanceID(PP_Module module, PP_Instance instance) {
  29   // Default to returning true (usable) failure. Otherwise, if there's some
  30   // kind of communication error or the plugin just crashed, we'll get into an
  31   // infinite loop generating new instnace IDs since we think they're all in
  32   // use.
  33   ModuleToDispatcherMap::const_iterator found =
  34       g_module_to_dispatcher->find(module);
  35   if (found == g_module_to_dispatcher->end()) {
  36     NOTREACHED();
  37     return PP_TRUE;
  38   }
  39
  40   bool usable = true;
  41   if (!found->second->Send(new PpapiMsg_ReserveInstanceId(instance, &usable)))
  42     return PP_TRUE;
  43   return PP_FromBool(usable);
  44 }
  45
  46 // Saves the state of the given bool and puts it back when it goes out of
  47 // scope.
  48 class BoolRestorer {
  49  public:
  50   BoolRestorer(bool* var) : var_(var), old_value_(*var) {
  51   }
  52   ~BoolRestorer() {
  53     *var_ = old_value_;
  54   }
  55  private:
  56   bool* var_;
  57   bool old_value_;
  58 };
  59
  60 }  // namespace
  61
  62 HostDispatcher::HostDispatcher(PP_Module module,
  63                                PP_GetInterface_Func local_get_interface,
  64                                const PpapiPermissions& permissions)
  65     : Dispatcher(local_get_interface, permissions),
  66       pp_module_(module),
  67       ppb_proxy_(NULL),
  68       allow_plugin_reentrancy_(false),
  69       weak_ptr_factory_(this) {
  70   if (!g_module_to_dispatcher)
  71     g_module_to_dispatcher = new ModuleToDispatcherMap;
  72   (*g_module_to_dispatcher)[pp_module_] = this;
  73
  74   SetSerializationRules(new HostVarSerializationRules);
  75
  76   ppb_proxy_ = reinterpret_cast<const PPB_Proxy_Private*>(
  77       local_get_interface(PPB_PROXY_PRIVATE_INTERFACE));
  78   DCHECK(ppb_proxy_) << "The proxy interface should always be supported.";
  79
  80   ppb_proxy_->SetReserveInstanceIDCallback(pp_module_, &ReserveInstanceID);
  81 }
  82
  83 HostDispatcher::~HostDispatcher() {
  84   g_module_to_dispatcher->erase(pp_module_);
  85 }
  86
  87 bool HostDispatcher::InitHostWithChannel(
  88     Delegate* delegate,
  89     base::ProcessId peer_pid,
  90     const IPC::ChannelHandle& channel_handle,
  91     bool is_client,
  92     const ppapi::Preferences& preferences) {
  93   if (!Dispatcher::InitWithChannel(delegate, peer_pid, channel_handle,
  94                                    is_client))
  95     return false;
  96   Send(new PpapiMsg_SetPreferences(preferences));
  97   return true;
  98 }
  99
 100 // static
 101 HostDispatcher* HostDispatcher::GetForInstance(PP_Instance instance) {
 102   if (!g_instance_to_dispatcher)
 103     return NULL;
 104   InstanceToDispatcherMap::iterator found = g_instance_to_dispatcher->find(
 105       instance);
 106   if (found == g_instance_to_dispatcher->end())
 107     return NULL;
 108   return found->second;
 109 }
 110
 111 // static
 112 void HostDispatcher::SetForInstance(PP_Instance instance,
 113                                     HostDispatcher* dispatcher) {
 114   if (!g_instance_to_dispatcher)
 115     g_instance_to_dispatcher = new InstanceToDispatcherMap;
 116   (*g_instance_to_dispatcher)[instance] = dispatcher;
 117 }
 118
 119 // static
 120 void HostDispatcher::RemoveForInstance(PP_Instance instance) {
 121   if (!g_instance_to_dispatcher)
 122     return;
 123   InstanceToDispatcherMap::iterator found = g_instance_to_dispatcher->find(
 124       instance);
 125   if (found != g_instance_to_dispatcher->end())
 126     g_instance_to_dispatcher->erase(found);
 127 }
 128
 129 bool HostDispatcher::IsPlugin() const {
 130   return false;
 131 }
 132
 133 bool HostDispatcher::Send(IPC::Message* msg) {
 134   TRACE_EVENT2("ppapi proxy", "HostDispatcher::Send",
 135                "Class", IPC_MESSAGE_ID_CLASS(msg->type()),
 136                "Line", IPC_MESSAGE_ID_LINE(msg->type()));
 137
 138   // Normal sync messages are set to unblock, which would normally cause the
 139   // plugin to be reentered to process them. We only want to do this when we
 140   // know the plugin is in a state to accept reentrancy. Since the plugin side
 141   // never clears this flag on messages it sends, we can't get deadlock, but we
 142   // may still get reentrancy in the host as a result.
 143   if (!allow_plugin_reentrancy_)
 144     msg->set_unblock(false);
 145
 146   if (msg->is_sync()) {
 147     // Don't allow sending sync messages during module shutdown. Seee the "else"
 148     // block below for why.
 149     CHECK(!PP_ToBool(ppb_proxy()->IsInModuleDestructor(pp_module())));
 150
 151     // Prevent the dispatcher from going away during sync calls. Scenarios
 152     // where this could happen include a Send for a sync message which while
 153     // waiting for the reply, dispatches an incoming ExecuteScript call which
 154     // destroys the plugin module and in turn the dispatcher.
 155     ScopedModuleReference scoped_ref(this);
 156
 157     FOR_EACH_OBSERVER(SyncMessageStatusObserver, sync_status_observer_list_,
 158                       BeginBlockOnSyncMessage());
 159     bool result = Dispatcher::Send(msg);
 160     FOR_EACH_OBSERVER(SyncMessageStatusObserver, sync_status_observer_list_,
 161                       EndBlockOnSyncMessage());
 162
 163     return result;
 164   } else {
 165     // We don't want to have a scoped ref for async message cases since since
 166     // async messages are sent during module desruction. In this case, the
 167     // module will have a 0 refcount and addrefing and releasing it will
 168     // reenter the destructor and it will crash.
 169     return Dispatcher::Send(msg);
 170   }
 171 }
 172
 173 bool HostDispatcher::OnMessageReceived(const IPC::Message& msg) {
 174   // Prevent the dispatcher from going away during a message handler. This must
 175   // be at the outermost scope so it's released last.
 176   ScopedModuleReference death_grip(this);
 177
 178   TRACE_EVENT2("ppapi proxy", "HostDispatcher::OnMessageReceived",
 179                "Class", IPC_MESSAGE_ID_CLASS(msg.type()),
 180                "Line", IPC_MESSAGE_ID_LINE(msg.type()));
 181
 182   // We only want to allow reentrancy when the most recent message from the
 183   // plugin was a scripting message. We save the old state of the flag on the
 184   // stack in case we're (we are the host) being reentered ourselves. The flag
 185   // is set to false here for all messages, and then the scripting API will
 186   // explicitly set it to true during processing of those messages that can be
 187   // reentered.
 188   BoolRestorer restorer(&allow_plugin_reentrancy_);
 189   allow_plugin_reentrancy_ = false;
 190
 191   for (size_t i = 0; i < filters_.size(); i++) {
 192     if (filters_[i]->OnMessageReceived(msg))
 193       return true;
 194   }
 195
 196   bool handled = true;
 197   IPC_BEGIN_MESSAGE_MAP(HostDispatcher, msg)
 198     IPC_MESSAGE_HANDLER(PpapiHostMsg_LogWithSource, OnHostMsgLogWithSource)
 199     IPC_MESSAGE_UNHANDLED(handled = false)
 200   IPC_END_MESSAGE_MAP()
 201
 202   if (handled)
 203     return true;
 204   return Dispatcher::OnMessageReceived(msg);
 205
 206   // Note: |this| may be deleted once the death_grip goes out of scope!
 207 }
 208
 209 void HostDispatcher::OnChannelError() {
 210   Dispatcher::OnChannelError();  // Stop using the channel.
 211
 212   // Tell the host about the crash so it can clean up and display notification.
 213   ppb_proxy_->PluginCrashed(pp_module());
 214 }
 215
 216 const void* HostDispatcher::GetProxiedInterface(const std::string& iface_name) {
 217   const void* proxied_interface =
 218       InterfaceList::GetInstance()->GetInterfaceForPPP(iface_name);
 219   if (!proxied_interface)
 220     return NULL;  // Don't have a proxy for this interface, don't query further.
 221
 222   PluginSupportedMap::iterator iter(plugin_supported_.find(iface_name));
 223   if (iter == plugin_supported_.end()) {
 224     // Need to query. Cache the result so we only do this once.
 225     bool supported = false;
 226
 227     bool previous_reentrancy_value = allow_plugin_reentrancy_;
 228     allow_plugin_reentrancy_ = true;
 229     Send(new PpapiMsg_SupportsInterface(iface_name, &supported));
 230     allow_plugin_reentrancy_ = previous_reentrancy_value;
 231
 232     std::pair<PluginSupportedMap::iterator, bool> iter_success_pair;
 233     iter_success_pair = plugin_supported_.insert(
 234         PluginSupportedMap::value_type(iface_name, supported));
 235     iter = iter_success_pair.first;
 236   }
 237   if (iter->second)
 238     return proxied_interface;
 239   return NULL;
 240 }
 241
 242 base::Closure HostDispatcher::AddSyncMessageStatusObserver(
 243     SyncMessageStatusObserver* obs) {
 244   sync_status_observer_list_.AddObserver(obs);
 245   return base::Bind(&HostDispatcher::RemoveSyncMessageStatusObserver,
 246                     weak_ptr_factory_.GetWeakPtr(),
 247                     obs);
 248 }
 249
 250 void HostDispatcher::RemoveSyncMessageStatusObserver(
 251     SyncMessageStatusObserver* obs) {
 252   sync_status_observer_list_.RemoveObserver(obs);
 253 }
 254
 255 void HostDispatcher::AddFilter(IPC::Listener* listener) {
 256   filters_.push_back(listener);
 257 }
 258
 259 void HostDispatcher::OnInvalidMessageReceived() {
 260   // TODO(brettw) bug 95345 kill the plugin when an invalid message is
 261   // received.
 262 }
 263
 264 void HostDispatcher::OnHostMsgLogWithSource(PP_Instance instance,
 265                                             int int_log_level,
 266                                             const std::string& source,
 267                                             const std::string& value) {
 268   PP_LogLevel level = static_cast<PP_LogLevel>(int_log_level);
 269   if (instance) {
 270     PpapiGlobals::Get()->LogWithSource(instance, level, source, value);
 271   } else {
 272     PpapiGlobals::Get()->BroadcastLogWithSource(pp_module_, level,
 273                                                 source, value);
 274   }
 275 }
 276
 277 // ScopedModuleReference -------------------------------------------------------
 278
 279 ScopedModuleReference::ScopedModuleReference(Dispatcher* dispatcher)
 280     : dispatcher_(NULL) {
 281   if (!dispatcher->IsPlugin()) {
 282     dispatcher_ = static_cast<HostDispatcher*>(dispatcher);
 283     dispatcher_->ppb_proxy()->AddRefModule(dispatcher_->pp_module());
 284   }
 285 }
 286
 287 ScopedModuleReference::~ScopedModuleReference() {
 288   if (dispatcher_)
 289     dispatcher_->ppb_proxy()->ReleaseModule(dispatcher_->pp_module());
 290 }
 291
 292 }  // namespace proxy
 293 }  // namespace ppapi