content/browser/media/midi_host.cc

   1 // Copyright (c) 2013 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 "content/browser/media/midi_host.h"
   6
   7 #include "base/bind.h"
   8 #include "base/bind_helpers.h"
   9 #include "base/debug/trace_event.h"
  10 #include "base/process/process.h"
  11 #include "content/browser/browser_main_loop.h"
  12 #include "content/browser/child_process_security_policy_impl.h"
  13 #include "content/browser/media/media_internals.h"
  14 #include "content/common/media/midi_messages.h"
  15 #include "content/public/browser/content_browser_client.h"
  16 #include "content/public/browser/media_observer.h"
  17 #include "content/public/browser/user_metrics.h"
  18 #include "media/midi/midi_manager.h"
  19 #include "media/midi/midi_message_queue.h"
  20 #include "media/midi/midi_message_util.h"
  21
  22 using media::MidiManager;
  23 using media::MidiPortInfoList;
  24
  25 namespace content {
  26 namespace {
  27
  28 // The total number of bytes which we're allowed to send to the OS
  29 // before knowing that they have been successfully sent.
  30 const size_t kMaxInFlightBytes = 10 * 1024 * 1024;  // 10 MB.
  31
  32 // We keep track of the number of bytes successfully sent to
  33 // the hardware.  Every once in a while we report back to the renderer
  34 // the number of bytes sent since the last report. This threshold determines
  35 // how many bytes will be sent before reporting back to the renderer.
  36 const size_t kAcknowledgementThresholdBytes = 1024 * 1024;  // 1 MB.
  37
  38 bool IsDataByte(uint8 data) {
  39   return (data & 0x80) == 0;
  40 }
  41
  42 bool IsSystemRealTimeMessage(uint8 data) {
  43   return 0xf8 <= data && data <= 0xff;
  44 }
  45
  46 }  // namespace
  47
  48 using media::kSysExByte;
  49 using media::kEndOfSysExByte;
  50
  51 MidiHost::MidiHost(int renderer_process_id, media::MidiManager* midi_manager)
  52     : BrowserMessageFilter(MidiMsgStart),
  53       renderer_process_id_(renderer_process_id),
  54       has_sys_ex_permission_(false),
  55       is_session_requested_(false),
  56       midi_manager_(midi_manager),
  57       sent_bytes_in_flight_(0),
  58       bytes_sent_since_last_acknowledgement_(0) {
  59   CHECK(midi_manager_);
  60 }
  61
  62 MidiHost::~MidiHost() {
  63   // Close an open session, or abort opening a session.
  64   if (is_session_requested_)
  65     midi_manager_->EndSession(this);
  66 }
  67
  68 void MidiHost::OnDestruct() const {
  69   BrowserThread::DeleteOnIOThread::Destruct(this);
  70 }
  71
  72 // IPC Messages handler
  73 bool MidiHost::OnMessageReceived(const IPC::Message& message) {
  74   bool handled = true;
  75   IPC_BEGIN_MESSAGE_MAP(MidiHost, message)
  76     IPC_MESSAGE_HANDLER(MidiHostMsg_StartSession, OnStartSession)
  77     IPC_MESSAGE_HANDLER(MidiHostMsg_SendData, OnSendData)
  78     IPC_MESSAGE_HANDLER(MidiHostMsg_EndSession, OnEndSession)
  79     IPC_MESSAGE_UNHANDLED(handled = false)
  80   IPC_END_MESSAGE_MAP()
  81
  82   return handled;
  83 }
  84
  85 void MidiHost::OnStartSession() {
  86   is_session_requested_ = true;
  87   midi_manager_->StartSession(this);
  88 }
  89
  90 void MidiHost::OnSendData(uint32 port,
  91                           const std::vector<uint8>& data,
  92                           double timestamp) {
  93   if (data.empty())
  94     return;
  95
  96   // Blink running in a renderer checks permission to raise a SecurityError
  97   // in JavaScript. The actual permission check for security purposes
  98   // happens here in the browser process.
  99   if (!has_sys_ex_permission_ &&
 100       std::find(data.begin(), data.end(), kSysExByte) != data.end()) {
 101     RecordAction(base::UserMetricsAction("BadMessageTerminate_MIDI"));
 102     BadMessageReceived();
 103     return;
 104   }
 105
 106   if (!IsValidWebMIDIData(data))
 107     return;
 108
 109   {
 110     base::AutoLock auto_lock(in_flight_lock_);
 111     // Sanity check that we won't send too much data.
 112     // TODO(yukawa): Consider to send an error event back to the renderer
 113     // after some future discussion in W3C.
 114     if (data.size() + sent_bytes_in_flight_ > kMaxInFlightBytes)
 115       return;
 116     sent_bytes_in_flight_ += data.size();
 117   }
 118   midi_manager_->DispatchSendMidiData(this, port, data, timestamp);
 119 }
 120
 121 void MidiHost::OnEndSession() {
 122   is_session_requested_ = false;
 123   midi_manager_->EndSession(this);
 124 }
 125
 126 void MidiHost::CompleteStartSession(media::MidiResult result) {
 127   DCHECK(is_session_requested_);
 128   if (result == media::MIDI_OK) {
 129     // ChildSecurityPolicy is set just before OnStartSession by
 130     // MidiDispatcherHost. So we can safely cache the policy.
 131     has_sys_ex_permission_ = ChildProcessSecurityPolicyImpl::GetInstance()->
 132         CanSendMidiSysExMessage(renderer_process_id_);
 133   }
 134   Send(new MidiMsg_SessionStarted(result));
 135 }
 136
 137 void MidiHost::AddInputPort(const media::MidiPortInfo& info) {
 138   base::AutoLock auto_lock(messages_queues_lock_);
 139   // MidiMessageQueue is created later in ReceiveMidiData().
 140   received_messages_queues_.push_back(nullptr);
 141   Send(new MidiMsg_AddInputPort(info));
 142 }
 143
 144 void MidiHost::AddOutputPort(const media::MidiPortInfo& info) {
 145   Send(new MidiMsg_AddOutputPort(info));
 146 }
 147
 148 void MidiHost::ReceiveMidiData(
 149     uint32 port,
 150     const uint8* data,
 151     size_t length,
 152     double timestamp) {
 153   TRACE_EVENT0("midi", "MidiHost::ReceiveMidiData");
 154
 155   base::AutoLock auto_lock(messages_queues_lock_);
 156   if (received_messages_queues_.size() <= port)
 157     return;
 158
 159   // Lazy initialization
 160   if (received_messages_queues_[port] == nullptr)
 161     received_messages_queues_[port] = new media::MidiMessageQueue(true);
 162
 163   received_messages_queues_[port]->Add(data, length);
 164   std::vector<uint8> message;
 165   while (true) {
 166     received_messages_queues_[port]->Get(&message);
 167     if (message.empty())
 168       break;
 169
 170     // MIDI devices may send a system exclusive messages even if the renderer
 171     // doesn't have a permission to receive it. Don't kill the renderer as
 172     // OnSendData() does.
 173     if (message[0] == kSysExByte && !has_sys_ex_permission_)
 174       continue;
 175
 176     // Send to the renderer.
 177     Send(new MidiMsg_DataReceived(port, message, timestamp));
 178   }
 179 }
 180
 181 void MidiHost::AccumulateMidiBytesSent(size_t n) {
 182   {
 183     base::AutoLock auto_lock(in_flight_lock_);
 184     if (n <= sent_bytes_in_flight_)
 185       sent_bytes_in_flight_ -= n;
 186   }
 187
 188   if (bytes_sent_since_last_acknowledgement_ + n >=
 189       bytes_sent_since_last_acknowledgement_)
 190     bytes_sent_since_last_acknowledgement_ += n;
 191
 192   if (bytes_sent_since_last_acknowledgement_ >=
 193       kAcknowledgementThresholdBytes) {
 194     Send(new MidiMsg_AcknowledgeSentData(
 195         bytes_sent_since_last_acknowledgement_));
 196     bytes_sent_since_last_acknowledgement_ = 0;
 197   }
 198 }
 199
 200 // static
 201 bool MidiHost::IsValidWebMIDIData(const std::vector<uint8>& data) {
 202   bool in_sysex = false;
 203   size_t waiting_data_length = 0;
 204   for (size_t i = 0; i < data.size(); ++i) {
 205     const uint8 current = data[i];
 206     if (IsSystemRealTimeMessage(current))
 207       continue;  // Real time message can be placed at any point.
 208     if (waiting_data_length > 0) {
 209       if (!IsDataByte(current))
 210         return false;  // Error: |current| should have been data byte.
 211       --waiting_data_length;
 212       continue;  // Found data byte as expected.
 213     }
 214     if (in_sysex) {
 215       if (data[i] == kEndOfSysExByte)
 216         in_sysex = false;
 217       else if (!IsDataByte(current))
 218         return false;  // Error: |current| should have been data byte.
 219       continue;  // Found data byte as expected.
 220     }
 221     if (current == kSysExByte) {
 222       in_sysex = true;
 223       continue;  // Found SysEX
 224     }
 225     waiting_data_length = media::GetMidiMessageLength(current);
 226     if (waiting_data_length == 0)
 227       return false;  // Error: |current| should have been a valid status byte.
 228     --waiting_data_length;  // Found status byte
 229   }
 230   return waiting_data_length == 0 && !in_sysex;
 231 }
 232
 233 }  // namespace content