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 "content/browser/histogram_message_filter.h"
6
7#include "base/command_line.h"
8#include "base/metrics/histogram.h"
9#include "base/metrics/statistics_recorder.h"
10#include "content/browser/histogram_controller.h"
11#include "content/browser/tcmalloc_internals_request_job.h"
12#include "content/common/child_process_messages.h"
13#include "content/public/common/content_switches.h"
14
15namespace content {
16
17HistogramMessageFilter::HistogramMessageFilter()
18    : BrowserMessageFilter(ChildProcessMsgStart) {}
19
20bool HistogramMessageFilter::OnMessageReceived(const IPC::Message& message) {
21  bool handled = true;
22  IPC_BEGIN_MESSAGE_MAP(HistogramMessageFilter, message)
23    IPC_MESSAGE_HANDLER(ChildProcessHostMsg_ChildHistogramData,
24                        OnChildHistogramData)
25    IPC_MESSAGE_HANDLER(ChildProcessHostMsg_GetBrowserHistogram,
26                        OnGetBrowserHistogram)
27    IPC_MESSAGE_UNHANDLED(handled = false)
28  IPC_END_MESSAGE_MAP()
29  return handled;
30}
31
32HistogramMessageFilter::~HistogramMessageFilter() {}
33
34void HistogramMessageFilter::OnChildHistogramData(
35    int sequence_number,
36    const std::vector<std::string>& pickled_histograms) {
37  HistogramController::GetInstance()->OnHistogramDataCollected(
38      sequence_number, pickled_histograms);
39}
40
41void HistogramMessageFilter::OnGetBrowserHistogram(
42    const std::string& name,
43    std::string* histogram_json) {
44  DCHECK(content::BrowserThread::CurrentlyOn(content::BrowserThread::IO));
45  // Security: Only allow access to browser histograms when running in the
46  // context of a test.
47  bool using_stats_collection_controller =
48      base::CommandLine::ForCurrentProcess()->HasSwitch(
49          switches::kStatsCollectionController);
50  if (!using_stats_collection_controller) {
51    LOG(ERROR) << "Attempt at reading browser histogram without specifying "
52               << "--" << switches::kStatsCollectionController << " switch.";
53    return;
54  }
55  base::HistogramBase* histogram =
56      base::StatisticsRecorder::FindHistogram(name);
57  if (!histogram) {
58    *histogram_json = "{}";
59  } else {
60    histogram->WriteJSON(histogram_json);
61  }
62}
63
64}  // namespace content
65