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/process/process.h"
  10 #include "base/trace_event/trace_event.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       output_port_count_(0) {
  60   CHECK(midi_manager_);
  61 }
  62
  63 MidiHost::~MidiHost() {
  64   // Close an open session, or abort opening a session.
  65   if (is_session_requested_)
  66     midi_manager_->EndSession(this);
  67 }
  68
  69 void MidiHost::OnDestruct() const {
  70   BrowserThread::DeleteOnIOThread::Destruct(this);
  71 }
  72
  73 // IPC Messages handler
  74 bool MidiHost::OnMessageReceived(const IPC::Message& message) {
  75   bool handled = true;
  76   IPC_BEGIN_MESSAGE_MAP(MidiHost, message)
  77     IPC_MESSAGE_HANDLER(MidiHostMsg_StartSession, OnStartSession)
  78     IPC_MESSAGE_HANDLER(MidiHostMsg_SendData, OnSendData)
  79     IPC_MESSAGE_HANDLER(MidiHostMsg_EndSession, OnEndSession)
  80     IPC_MESSAGE_UNHANDLED(handled = false)
  81   IPC_END_MESSAGE_MAP()
  82
  83   return handled;
  84 }
  85
  86 void MidiHost::OnStartSession() {
  87   is_session_requested_ = true;
  88   midi_manager_->StartSession(this);
  89 }
  90
  91 void MidiHost::OnSendData(uint32 port,
  92                           const std::vector<uint8>& data,
  93                           double timestamp) {
  94   {
  95     base::AutoLock auto_lock(output_port_count_lock_);
  96     if (output_port_count_ <= port) {
  97       RecordAction(base::UserMetricsAction("BadMessageTerminate_MIDIPort"));
  98       BadMessageReceived();
  99       return;
 100     }
 101   }
 102
 103   if (data.empty())
 104     return;
 105
 106   // Blink running in a renderer checks permission to raise a SecurityError
 107   // in JavaScript. The actual permission check for security purposes
 108   // happens here in the browser process.
 109   if (!has_sys_ex_permission_ &&
 110       std::find(data.begin(), data.end(), kSysExByte) != data.end()) {
 111     RecordAction(base::UserMetricsAction("BadMessageTerminate_MIDI"));
 112     BadMessageReceived();
 113     return;
 114   }
 115
 116   if (!IsValidWebMIDIData(data))
 117     return;
 118
 119   {
 120     base::AutoLock auto_lock(in_flight_lock_);
 121     // Sanity check that we won't send too much data.
 122     // TODO(yukawa): Consider to send an error event back to the renderer
 123     // after some future discussion in W3C.
 124     if (data.size() + sent_bytes_in_flight_ > kMaxInFlightBytes)
 125       return;
 126     sent_bytes_in_flight_ += data.size();
 127   }
 128   midi_manager_->DispatchSendMidiData(this, port, data, timestamp);
 129 }
 130
 131 void MidiHost::OnEndSession() {
 132   is_session_requested_ = false;
 133   midi_manager_->EndSession(this);
 134 }
 135
 136 void MidiHost::CompleteStartSession(media::MidiResult result) {
 137   DCHECK(is_session_requested_);
 138   if (result == media::MIDI_OK) {
 139     // ChildSecurityPolicy is set just before OnStartSession by
 140     // MidiDispatcherHost. So we can safely cache the policy.
 141     has_sys_ex_permission_ = ChildProcessSecurityPolicyImpl::GetInstance()->
 142         CanSendMidiSysExMessage(renderer_process_id_);
 143   }
 144   Send(new MidiMsg_SessionStarted(result));
 145 }
 146
 147 void MidiHost::AddInputPort(const media::MidiPortInfo& info) {
 148   base::AutoLock auto_lock(messages_queues_lock_);
 149   // MidiMessageQueue is created later in ReceiveMidiData().
 150   received_messages_queues_.push_back(nullptr);
 151   Send(new MidiMsg_AddInputPort(info));
 152 }
 153
 154 void MidiHost::AddOutputPort(const media::MidiPortInfo& info) {
 155   base::AutoLock auto_lock(output_port_count_lock_);
 156   output_port_count_++;
 157   Send(new MidiMsg_AddOutputPort(info));
 158 }
 159
 160 void MidiHost::SetInputPortState(uint32 port, media::MidiPortState state) {
 161   Send(new MidiMsg_SetInputPortState(port, state));
 162 }
 163
 164 void MidiHost::SetOutputPortState(uint32 port, media::MidiPortState state) {
 165   Send(new MidiMsg_SetOutputPortState(port, state));
 166 }
 167
 168 void MidiHost::ReceiveMidiData(
 169     uint32 port,
 170     const uint8* data,
 171     size_t length,
 172     double timestamp) {
 173   TRACE_EVENT0("midi", "MidiHost::ReceiveMidiData");
 174
 175   base::AutoLock auto_lock(messages_queues_lock_);
 176   if (received_messages_queues_.size() <= port)
 177     return;
 178
 179   // Lazy initialization
 180   if (received_messages_queues_[port] == nullptr)
 181     received_messages_queues_[port] = new media::MidiMessageQueue(true);
 182
 183   received_messages_queues_[port]->Add(data, length);
 184   std::vector<uint8> message;
 185   while (true) {
 186     received_messages_queues_[port]->Get(&message);
 187     if (message.empty())
 188       break;
 189
 190     // MIDI devices may send a system exclusive messages even if the renderer
 191     // doesn't have a permission to receive it. Don't kill the renderer as
 192     // OnSendData() does.
 193     if (message[0] == kSysExByte && !has_sys_ex_permission_)
 194       continue;
 195
 196     // Send to the renderer.
 197     Send(new MidiMsg_DataReceived(port, message, timestamp));
 198   }
 199 }
 200
 201 void MidiHost::AccumulateMidiBytesSent(size_t n) {
 202   {
 203     base::AutoLock auto_lock(in_flight_lock_);
 204     if (n <= sent_bytes_in_flight_)
 205       sent_bytes_in_flight_ -= n;
 206   }
 207
 208   if (bytes_sent_since_last_acknowledgement_ + n >=
 209       bytes_sent_since_last_acknowledgement_)
 210     bytes_sent_since_last_acknowledgement_ += n;
 211
 212   if (bytes_sent_since_last_acknowledgement_ >=
 213       kAcknowledgementThresholdBytes) {
 214     Send(new MidiMsg_AcknowledgeSentData(
 215         bytes_sent_since_last_acknowledgement_));
 216     bytes_sent_since_last_acknowledgement_ = 0;
 217   }
 218 }
 219
 220 // static
 221 bool MidiHost::IsValidWebMIDIData(const std::vector<uint8>& data) {
 222   bool in_sysex = false;
 223   size_t waiting_data_length = 0;
 224   for (size_t i = 0; i < data.size(); ++i) {
 225     const uint8 current = data[i];
 226     if (IsSystemRealTimeMessage(current))
 227       continue;  // Real time message can be placed at any point.
 228     if (waiting_data_length > 0) {
 229       if (!IsDataByte(current))
 230         return false;  // Error: |current| should have been data byte.
 231       --waiting_data_length;
 232       continue;  // Found data byte as expected.
 233     }
 234     if (in_sysex) {
 235       if (data[i] == kEndOfSysExByte)
 236         in_sysex = false;
 237       else if (!IsDataByte(current))
 238         return false;  // Error: |current| should have been data byte.
 239       continue;  // Found data byte as expected.
 240     }
 241     if (current == kSysExByte) {
 242       in_sysex = true;
 243       continue;  // Found SysEX
 244     }
 245     waiting_data_length = media::GetMidiMessageLength(current);
 246     if (waiting_data_length == 0)
 247       return false;  // Error: |current| should have been a valid status byte.
 248     --waiting_data_length;  // Found status byte
 249   }
 250   return waiting_data_length == 0 && !in_sysex;
 251 }
 252
 253 }  // namespace content