Limit the number of simultaneous event logs.

webrtc/logging/rtc_event_log/rtc_event_log.cc

 /*
  *  Copyright (c) 2015 The WebRTC project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 
 #include "webrtc/logging/rtc_event_log/rtc_event_log.h"
 
 #include <limits>
 #include <vector>
 
+#include "webrtc/base/atomicops.h"
 #include "webrtc/base/checks.h"
 #include "webrtc/base/constructormagic.h"
 #include "webrtc/base/event.h"
 #include "webrtc/base/logging.h"
 #include "webrtc/base/protobuf_utils.h"
 #include "webrtc/base/swap_queue.h"
 #include "webrtc/base/thread_checker.h"
 #include "webrtc/base/timeutils.h"
 #include "webrtc/logging/rtc_event_log/rtc_event_log_helper_thread.h"
 #include "webrtc/modules/audio_coding/audio_network_adaptor/include/audio_network_adaptor.h"
@@ skipping 19 matching lines @@
 #else
 #include "webrtc/logging/rtc_event_log/rtc_event_log.pb.h"
 #endif
 #endif
 
 namespace webrtc {
 
 #ifdef ENABLE_RTC_EVENT_LOG
 
 class RtcEventLogImpl final : public RtcEventLog {
+  friend std::unique_ptr<RtcEventLog> RtcEventLog::Create();
+
  public:
-  RtcEventLogImpl();
   ~RtcEventLogImpl() override;
 
   bool StartLogging(const std::string& file_name,
                     int64_t max_size_bytes) override;
   bool StartLogging(rtc::PlatformFile platform_file,
                     int64_t max_size_bytes) override;
   void StopLogging() override;
   void LogVideoReceiveStreamConfig(const rtclog::StreamConfig& config) override;
   void LogVideoSendStreamConfig(const rtclog::StreamConfig& config) override;
   void LogAudioReceiveStreamConfig(const rtclog::StreamConfig& config) override;
@@ skipping 18 matching lines @@
       const AudioEncoderRuntimeConfig& config) override;
   void LogProbeClusterCreated(int id,
                               int bitrate_bps,
                               int min_probes,
                               int min_bytes) override;
   void LogProbeResultSuccess(int id, int bitrate_bps) override;
   void LogProbeResultFailure(int id,
                              ProbeFailureReason failure_reason) override;
 
  private:
+  // Private constructor to ensure that creation is done by RtcEventLog::Create.
+  RtcEventLogImpl();
+
   void StoreEvent(std::unique_ptr<rtclog::Event>* event);
   void LogProbeResult(int id,
                       rtclog::BweProbeResult::ResultType result,
                       int bitrate_bps);
 
+  static volatile int log_count_;
+
   // Message queue for passing control messages to the logging thread.
   SwapQueue<RtcEventLogHelperThread::ControlMessage> message_queue_;
 
   // Message queue for passing events to the logging thread.
   SwapQueue<std::unique_ptr<rtclog::Event> > event_queue_;
 
   RtcEventLogHelperThread helper_thread_;
   rtc::ThreadChecker thread_checker_;
 
   RTC_DISALLOW_COPY_AND_ASSIGN(RtcEventLogImpl);
@@ skipping 45 matching lines @@
   RTC_NOTREACHED();
   return rtclog::BweProbeResult::SUCCESS;
 }
 
 // The RTP and RTCP buffers reserve space for twice the expected number of
 // sent packets because they also contain received packets.
 static const int kEventsPerSecond = 1000;
 static const int kControlMessagesPerSecond = 10;
 }  // namespace
 
+volatile int RtcEventLogImpl::log_count_ = 0;
+
 // RtcEventLogImpl member functions.
 RtcEventLogImpl::RtcEventLogImpl()
     // Allocate buffers for roughly one second of history.
     : message_queue_(kControlMessagesPerSecond),
       event_queue_(kEventsPerSecond),
       helper_thread_(&message_queue_, &event_queue_),
       thread_checker_() {
   thread_checker_.DetachFromThread();
 }
 
 RtcEventLogImpl::~RtcEventLogImpl() {
   // The RtcEventLogHelperThread destructor closes the file
   // and waits for the thread to terminate.
+  int count = rtc::AtomicOps::Decrement(&RtcEventLogImpl::log_count_);
+  RTC_DCHECK_GE(count, 0);
 }
 
 bool RtcEventLogImpl::StartLogging(const std::string& file_name,
                                    int64_t max_size_bytes) {
   RTC_DCHECK(thread_checker_.CalledOnValidThread());
   RtcEventLogHelperThread::ControlMessage message;
   message.message_type = RtcEventLogHelperThread::ControlMessage::START_FILE;
   message.max_size_bytes = max_size_bytes <= 0
                                ? std::numeric_limits<int64_t>::max()
                                : max_size_bytes;
@@ skipping 388 matching lines @@
   }
   dump_file->CloseFile();
   return result->ParseFromString(dump_buffer);
 }
 
 #endif  // ENABLE_RTC_EVENT_LOG
 
 // RtcEventLog member functions.
 std::unique_ptr<RtcEventLog> RtcEventLog::Create() {
 #ifdef ENABLE_RTC_EVENT_LOG
+  constexpr int kMaxLogCount = 5;
+  int count = rtc::AtomicOps::Increment(&RtcEventLogImpl::log_count_);
+  if (count > kMaxLogCount) {
+    LOG(LS_WARNING) << "Denied creation of additional WebRTC event logs. "
+                    << count - 1 << " logs open already.";
+    rtc::AtomicOps::Decrement(&RtcEventLogImpl::log_count_);
+    return std::unique_ptr<RtcEventLog>(new RtcEventLogNullImpl());
+  }
   return std::unique_ptr<RtcEventLog>(new RtcEventLogImpl());
 #else
   return std::unique_ptr<RtcEventLog>(new RtcEventLogNullImpl());
 #endif  // ENABLE_RTC_EVENT_LOG
 }
 
 std::unique_ptr<RtcEventLog> RtcEventLog::CreateNull() {
   return std::unique_ptr<RtcEventLog>(new RtcEventLogNullImpl());
 }
 
 }  // namespace webrtc