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                                SyncMessageStatusReceiver* sync_status,
  65                                const PpapiPermissions& permissions)
  66     : Dispatcher(local_get_interface, permissions),
  67       sync_status_(sync_status),
  68       pp_module_(module),
  69       ppb_proxy_(NULL),
  70       allow_plugin_reentrancy_(false) {
  71   if (!g_module_to_dispatcher)
  72     g_module_to_dispatcher = new ModuleToDispatcherMap;
  73   (*g_module_to_dispatcher)[pp_module_] = this;
  74
  75   SetSerializationRules(new HostVarSerializationRules);
  76
  77   ppb_proxy_ = reinterpret_cast<const PPB_Proxy_Private*>(
  78       local_get_interface(PPB_PROXY_PRIVATE_INTERFACE));
  79   DCHECK(ppb_proxy_) << "The proxy interface should always be supported.";
  80
  81   ppb_proxy_->SetReserveInstanceIDCallback(pp_module_, &ReserveInstanceID);
  82 }
  83
  84 HostDispatcher::~HostDispatcher() {
  85   g_module_to_dispatcher->erase(pp_module_);
  86 }
  87
  88 bool HostDispatcher::InitHostWithChannel(
  89     Delegate* delegate,
  90     base::ProcessId peer_pid,
  91     const IPC::ChannelHandle& channel_handle,
  92     bool is_client,
  93     const ppapi::Preferences& preferences) {
  94   if (!Dispatcher::InitWithChannel(delegate, peer_pid, channel_handle,
  95                                    is_client))
  96     return false;
  97   AddIOThreadMessageFilter(sync_status_.get());
  98
  99   Send(new PpapiMsg_SetPreferences(preferences));
 100   return true;
 101 }
 102
 103 // static
 104 HostDispatcher* HostDispatcher::GetForInstance(PP_Instance instance) {
 105   if (!g_instance_to_dispatcher)
 106     return NULL;
 107   InstanceToDispatcherMap::iterator found = g_instance_to_dispatcher->find(
 108       instance);
 109   if (found == g_instance_to_dispatcher->end())
 110     return NULL;
 111   return found->second;
 112 }
 113
 114 // static
 115 void HostDispatcher::SetForInstance(PP_Instance instance,
 116                                     HostDispatcher* dispatcher) {
 117   if (!g_instance_to_dispatcher)
 118     g_instance_to_dispatcher = new InstanceToDispatcherMap;
 119   (*g_instance_to_dispatcher)[instance] = dispatcher;
 120 }
 121
 122 // static
 123 void HostDispatcher::RemoveForInstance(PP_Instance instance) {
 124   if (!g_instance_to_dispatcher)
 125     return;
 126   InstanceToDispatcherMap::iterator found = g_instance_to_dispatcher->find(
 127       instance);
 128   if (found != g_instance_to_dispatcher->end())
 129     g_instance_to_dispatcher->erase(found);
 130 }
 131
 132 bool HostDispatcher::IsPlugin() const {
 133   return false;
 134 }
 135
 136 bool HostDispatcher::Send(IPC::Message* msg) {
 137   TRACE_EVENT2("ppapi proxy", "HostDispatcher::Send",
 138                "Class", IPC_MESSAGE_ID_CLASS(msg->type()),
 139                "Line", IPC_MESSAGE_ID_LINE(msg->type()));
 140
 141   // Normal sync messages are set to unblock, which would normally cause the
 142   // plugin to be reentered to process them. We only want to do this when we
 143   // know the plugin is in a state to accept reentrancy. Since the plugin side
 144   // never clears this flag on messages it sends, we can't get deadlock, but we
 145   // may still get reentrancy in the host as a result.
 146   if (!allow_plugin_reentrancy_)
 147     msg->set_unblock(false);
 148
 149   if (msg->is_sync()) {
 150     // Don't allow sending sync messages during module shutdown. Seee the "else"
 151     // block below for why.
 152     CHECK(!PP_ToBool(ppb_proxy()->IsInModuleDestructor(pp_module())));
 153
 154     // Prevent the dispatcher from going away during sync calls. Scenarios
 155     // where this could happen include a Send for a sync message which while
 156     // waiting for the reply, dispatches an incoming ExecuteScript call which
 157     // destroys the plugin module and in turn the dispatcher.
 158     ScopedModuleReference scoped_ref(this);
 159
 160     sync_status_->BeginBlockOnSyncMessage();
 161     bool result = Dispatcher::Send(msg);
 162     sync_status_->EndBlockOnSyncMessage();
 163
 164     return result;
 165   } else {
 166     // We don't want to have a scoped ref for async message cases since since
 167     // async messages are sent during module desruction. In this case, the
 168     // module will have a 0 refcount and addrefing and releasing it will
 169     // reenter the destructor and it will crash.
 170     return Dispatcher::Send(msg);
 171   }
 172 }
 173
 174 bool HostDispatcher::OnMessageReceived(const IPC::Message& msg) {
 175   // Prevent the dispatcher from going away during a message handler. This must
 176   // be at the outermost scope so it's released last.
 177   ScopedModuleReference death_grip(this);
 178
 179   TRACE_EVENT2("ppapi proxy", "HostDispatcher::OnMessageReceived",
 180                "Class", IPC_MESSAGE_ID_CLASS(msg.type()),
 181                "Line", IPC_MESSAGE_ID_LINE(msg.type()));
 182
 183   // We only want to allow reentrancy when the most recent message from the
 184   // plugin was a scripting message. We save the old state of the flag on the
 185   // stack in case we're (we are the host) being reentered ourselves. The flag
 186   // is set to false here for all messages, and then the scripting API will
 187   // explicitly set it to true during processing of those messages that can be
 188   // reentered.
 189   BoolRestorer restorer(&allow_plugin_reentrancy_);
 190   allow_plugin_reentrancy_ = false;
 191
 192   for (size_t i = 0; i < filters_.size(); i++) {
 193     if (filters_[i]->OnMessageReceived(msg))
 194       return true;
 195   }
 196
 197   bool handled = true;
 198   IPC_BEGIN_MESSAGE_MAP(HostDispatcher, msg)
 199     IPC_MESSAGE_HANDLER(PpapiHostMsg_LogWithSource, OnHostMsgLogWithSource)
 200     IPC_MESSAGE_UNHANDLED(handled = false)
 201   IPC_END_MESSAGE_MAP()
 202
 203   if (handled)
 204     return true;
 205   return Dispatcher::OnMessageReceived(msg);
 206
 207   // Note: |this| may be deleted once the death_grip goes out of scope!
 208 }
 209
 210 void HostDispatcher::OnChannelError() {
 211   Dispatcher::OnChannelError();  // Stop using the channel.
 212
 213   // Tell the host about the crash so it can clean up and display notification.
 214   ppb_proxy_->PluginCrashed(pp_module());
 215 }
 216
 217 const void* HostDispatcher::GetProxiedInterface(const std::string& iface_name) {
 218   const void* proxied_interface =
 219       InterfaceList::GetInstance()->GetInterfaceForPPP(iface_name);
 220   if (!proxied_interface)
 221     return NULL;  // Don't have a proxy for this interface, don't query further.
 222
 223   PluginSupportedMap::iterator iter(plugin_supported_.find(iface_name));
 224   if (iter == plugin_supported_.end()) {
 225     // Need to query. Cache the result so we only do this once.
 226     bool supported = false;
 227
 228     bool previous_reentrancy_value = allow_plugin_reentrancy_;
 229     allow_plugin_reentrancy_ = true;
 230     Send(new PpapiMsg_SupportsInterface(iface_name, &supported));
 231     allow_plugin_reentrancy_ = previous_reentrancy_value;
 232
 233     std::pair<PluginSupportedMap::iterator, bool> iter_success_pair;
 234     iter_success_pair = plugin_supported_.insert(
 235         PluginSupportedMap::value_type(iface_name, supported));
 236     iter = iter_success_pair.first;
 237   }
 238   if (iter->second)
 239     return proxied_interface;
 240   return NULL;
 241 }
 242
 243 void HostDispatcher::OnInvalidMessageReceived() {
 244   // TODO(brettw) bug 95345 kill the plugin when an invalid message is
 245   // received.
 246 }
 247
 248 void HostDispatcher::OnHostMsgLogWithSource(PP_Instance instance,
 249                                             int int_log_level,
 250                                             const std::string& source,
 251                                             const std::string& value) {
 252   PP_LogLevel level = static_cast<PP_LogLevel>(int_log_level);
 253   if (instance) {
 254     PpapiGlobals::Get()->LogWithSource(instance, level, source, value);
 255   } else {
 256     PpapiGlobals::Get()->BroadcastLogWithSource(pp_module_, level,
 257                                                 source, value);
 258   }
 259 }
 260
 261 // ScopedModuleReference -------------------------------------------------------
 262
 263 ScopedModuleReference::ScopedModuleReference(Dispatcher* dispatcher)
 264     : dispatcher_(NULL) {
 265   if (!dispatcher->IsPlugin()) {
 266     dispatcher_ = static_cast<HostDispatcher*>(dispatcher);
 267     dispatcher_->ppb_proxy()->AddRefModule(dispatcher_->pp_module());
 268   }
 269 }
 270
 271 ScopedModuleReference::~ScopedModuleReference() {
 272   if (dispatcher_)
 273     dispatcher_->ppb_proxy()->ReleaseModule(dispatcher_->pp_module());
 274 }
 275
 276 }  // namespace proxy
 277 }  // namespace ppapi