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/bad_message.h"
  12 #include "content/browser/browser_main_loop.h"
  13 #include "content/browser/child_process_security_policy_impl.h"
  14 #include "content/browser/media/media_internals.h"
  15 #include "content/common/media/midi_messages.h"
  16 #include "content/public/browser/content_browser_client.h"
  17 #include "content/public/browser/media_observer.h"
  18 #include "content/public/browser/user_metrics.h"
  19 #include "media/midi/midi_manager.h"
  20 #include "media/midi/midi_message_queue.h"
  21 #include "media/midi/midi_message_util.h"
  22
  23 namespace content {
  24 namespace {
  25
  26 // The total number of bytes which we're allowed to send to the OS
  27 // before knowing that they have been successfully sent.
  28 const size_t kMaxInFlightBytes = 10 * 1024 * 1024;  // 10 MB.
  29
  30 // We keep track of the number of bytes successfully sent to
  31 // the hardware.  Every once in a while we report back to the renderer
  32 // the number of bytes sent since the last report. This threshold determines
  33 // how many bytes will be sent before reporting back to the renderer.
  34 const size_t kAcknowledgementThresholdBytes = 1024 * 1024;  // 1 MB.
  35
  36 bool IsDataByte(uint8 data) {
  37   return (data & 0x80) == 0;
  38 }
  39
  40 bool IsSystemRealTimeMessage(uint8 data) {
  41   return 0xf8 <= data && data <= 0xff;
  42 }
  43
  44 }  // namespace
  45
  46 using media::midi::kSysExByte;
  47 using media::midi::kEndOfSysExByte;
  48
  49 MidiHost::MidiHost(int renderer_process_id,
  50                    media::midi::MidiManager* midi_manager)
  51     : BrowserMessageFilter(MidiMsgStart),
  52       renderer_process_id_(renderer_process_id),
  53       has_sys_ex_permission_(false),
  54       is_session_requested_(false),
  55       midi_manager_(midi_manager),
  56       sent_bytes_in_flight_(0),
  57       bytes_sent_since_last_acknowledgement_(0),
  58       output_port_count_(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   {
  94     base::AutoLock auto_lock(output_port_count_lock_);
  95     if (output_port_count_ <= port) {
  96       bad_message::ReceivedBadMessage(this, bad_message::MH_INVALID_MIDI_PORT);
  97       return;
  98     }
  99   }
 100
 101   if (data.empty())
 102     return;
 103
 104   // Blink running in a renderer checks permission to raise a SecurityError
 105   // in JavaScript. The actual permission check for security purposes
 106   // happens here in the browser process.
 107   if (!has_sys_ex_permission_ &&
 108       std::find(data.begin(), data.end(), kSysExByte) != data.end()) {
 109     bad_message::ReceivedBadMessage(this, bad_message::MH_SYS_EX_PERMISSION);
 110     return;
 111   }
 112
 113   if (!IsValidWebMIDIData(data))
 114     return;
 115
 116   {
 117     base::AutoLock auto_lock(in_flight_lock_);
 118     // Sanity check that we won't send too much data.
 119     // TODO(yukawa): Consider to send an error event back to the renderer
 120     // after some future discussion in W3C.
 121     if (data.size() + sent_bytes_in_flight_ > kMaxInFlightBytes)
 122       return;
 123     sent_bytes_in_flight_ += data.size();
 124   }
 125   midi_manager_->DispatchSendMidiData(this, port, data, timestamp);
 126 }
 127
 128 void MidiHost::OnEndSession() {
 129   is_session_requested_ = false;
 130   midi_manager_->EndSession(this);
 131 }
 132
 133 void MidiHost::CompleteStartSession(media::midi::Result result) {
 134   DCHECK(is_session_requested_);
 135   if (result == media::midi::Result::OK) {
 136     // ChildSecurityPolicy is set just before OnStartSession by
 137     // MidiDispatcherHost. So we can safely cache the policy.
 138     has_sys_ex_permission_ = ChildProcessSecurityPolicyImpl::GetInstance()->
 139         CanSendMidiSysExMessage(renderer_process_id_);
 140   }
 141   Send(new MidiMsg_SessionStarted(result));
 142 }
 143
 144 void MidiHost::AddInputPort(const media::midi::MidiPortInfo& info) {
 145   base::AutoLock auto_lock(messages_queues_lock_);
 146   // MidiMessageQueue is created later in ReceiveMidiData().
 147   received_messages_queues_.push_back(nullptr);
 148   Send(new MidiMsg_AddInputPort(info));
 149 }
 150
 151 void MidiHost::AddOutputPort(const media::midi::MidiPortInfo& info) {
 152   base::AutoLock auto_lock(output_port_count_lock_);
 153   output_port_count_++;
 154   Send(new MidiMsg_AddOutputPort(info));
 155 }
 156
 157 void MidiHost::SetInputPortState(uint32 port,
 158                                  media::midi::MidiPortState state) {
 159   Send(new MidiMsg_SetInputPortState(port, state));
 160 }
 161
 162 void MidiHost::SetOutputPortState(uint32 port,
 163                                   media::midi::MidiPortState state) {
 164   Send(new MidiMsg_SetOutputPortState(port, state));
 165 }
 166
 167 void MidiHost::ReceiveMidiData(
 168     uint32 port,
 169     const uint8* data,
 170     size_t length,
 171     double timestamp) {
 172   TRACE_EVENT0("midi", "MidiHost::ReceiveMidiData");
 173
 174   base::AutoLock auto_lock(messages_queues_lock_);
 175   if (received_messages_queues_.size() <= port)
 176     return;
 177
 178   // Lazy initialization
 179   if (received_messages_queues_[port] == nullptr)
 180     received_messages_queues_[port] = new media::midi::MidiMessageQueue(true);
 181
 182   received_messages_queues_[port]->Add(data, length);
 183   std::vector<uint8> message;
 184   while (true) {
 185     received_messages_queues_[port]->Get(&message);
 186     if (message.empty())
 187       break;
 188
 189     // MIDI devices may send a system exclusive messages even if the renderer
 190     // doesn't have a permission to receive it. Don't kill the renderer as
 191     // OnSendData() does.
 192     if (message[0] == kSysExByte && !has_sys_ex_permission_)
 193       continue;
 194
 195     // Send to the renderer.
 196     Send(new MidiMsg_DataReceived(port, message, timestamp));
 197   }
 198 }
 199
 200 void MidiHost::AccumulateMidiBytesSent(size_t n) {
 201   {
 202     base::AutoLock auto_lock(in_flight_lock_);
 203     if (n <= sent_bytes_in_flight_)
 204       sent_bytes_in_flight_ -= n;
 205   }
 206
 207   if (bytes_sent_since_last_acknowledgement_ + n >=
 208       bytes_sent_since_last_acknowledgement_)
 209     bytes_sent_since_last_acknowledgement_ += n;
 210
 211   if (bytes_sent_since_last_acknowledgement_ >=
 212       kAcknowledgementThresholdBytes) {
 213     Send(new MidiMsg_AcknowledgeSentData(
 214         bytes_sent_since_last_acknowledgement_));
 215     bytes_sent_since_last_acknowledgement_ = 0;
 216   }
 217 }
 218
 219 // static
 220 bool MidiHost::IsValidWebMIDIData(const std::vector<uint8>& data) {
 221   bool in_sysex = false;
 222   size_t waiting_data_length = 0;
 223   for (size_t i = 0; i < data.size(); ++i) {
 224     const uint8 current = data[i];
 225     if (IsSystemRealTimeMessage(current))
 226       continue;  // Real time message can be placed at any point.
 227     if (waiting_data_length > 0) {
 228       if (!IsDataByte(current))
 229         return false;  // Error: |current| should have been data byte.
 230       --waiting_data_length;
 231       continue;  // Found data byte as expected.
 232     }
 233     if (in_sysex) {
 234       if (data[i] == kEndOfSysExByte)
 235         in_sysex = false;
 236       else if (!IsDataByte(current))
 237         return false;  // Error: |current| should have been data byte.
 238       continue;  // Found data byte as expected.
 239     }
 240     if (current == kSysExByte) {
 241       in_sysex = true;
 242       continue;  // Found SysEX
 243     }
 244     waiting_data_length = media::midi::GetMidiMessageLength(current);
 245     if (waiting_data_length == 0)
 246       return false;  // Error: |current| should have been a valid status byte.
 247     --waiting_data_length;  // Found status byte
 248   }
 249   return waiting_data_length == 0 && !in_sysex;
 250 }
 251
 252 }  // namespace content