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      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 "base/trace_event/trace_event_impl.h"
      6 
      7 #include <fcntl.h>
      8 #include <stddef.h>
      9 #include <stdint.h>
     10 
     11 #include "base/format_macros.h"
     12 #include "base/logging.h"
     13 #include "base/posix/eintr_wrapper.h"
     14 #include "base/strings/stringprintf.h"
     15 #include "base/synchronization/waitable_event.h"
     16 #include "base/trace_event/trace_event.h"
     17 
     18 namespace base {
     19 namespace trace_event {
     20 
     21 namespace {
     22 
     23 int g_atrace_fd = -1;
     24 const char kATraceMarkerFile[] = "/sys/kernel/debug/tracing/trace_marker";
     25 
     26 void WriteToATrace(int fd, const char* buffer, size_t size) {
     27   size_t total_written = 0;
     28   while (total_written < size) {
     29     ssize_t written = HANDLE_EINTR(write(
     30         fd, buffer + total_written, size - total_written));
     31     if (written <= 0)
     32       break;
     33     total_written += written;
     34   }
     35   if (total_written < size) {
     36     PLOG(WARNING) << "Failed to write buffer '" << std::string(buffer, size)
     37                   << "' to " << kATraceMarkerFile;
     38   }
     39 }
     40 
     41 void WriteEvent(
     42     char phase,
     43     const char* category_group,
     44     const char* name,
     45     unsigned long long id,
     46     const char** arg_names,
     47     const unsigned char* arg_types,
     48     const TraceEvent::TraceValue* arg_values,
     49     const std::unique_ptr<ConvertableToTraceFormat>* convertable_values,
     50     unsigned int flags) {
     51   std::string out = StringPrintf("%c|%d|%s", phase, getpid(), name);
     52   if (flags & TRACE_EVENT_FLAG_HAS_ID)
     53     StringAppendF(&out, "-%" PRIx64, static_cast<uint64_t>(id));
     54   out += '|';
     55 
     56   for (int i = 0; i < kTraceMaxNumArgs && arg_names[i];
     57        ++i) {
     58     if (i)
     59       out += ';';
     60     out += arg_names[i];
     61     out += '=';
     62     std::string::size_type value_start = out.length();
     63     if (arg_types[i] == TRACE_VALUE_TYPE_CONVERTABLE)
     64       convertable_values[i]->AppendAsTraceFormat(&out);
     65     else
     66       TraceEvent::AppendValueAsJSON(arg_types[i], arg_values[i], &out);
     67 
     68     // Remove the quotes which may confuse the atrace script.
     69     ReplaceSubstringsAfterOffset(&out, value_start, "\\\"", "'");
     70     ReplaceSubstringsAfterOffset(&out, value_start, "\"", "");
     71     // Replace chars used for separators with similar chars in the value.
     72     std::replace(out.begin() + value_start, out.end(), ';', ',');
     73     std::replace(out.begin() + value_start, out.end(), '|', '!');
     74   }
     75 
     76   out += '|';
     77   out += category_group;
     78   WriteToATrace(g_atrace_fd, out.c_str(), out.size());
     79 }
     80 
     81 void NoOpOutputCallback(WaitableEvent* complete_event,
     82                         const scoped_refptr<RefCountedString>&,
     83                         bool has_more_events) {
     84   if (!has_more_events)
     85     complete_event->Signal();
     86 }
     87 
     88 void EndChromeTracing(TraceLog* trace_log,
     89                       WaitableEvent* complete_event) {
     90   trace_log->SetDisabled();
     91   // Delete the buffered trace events as they have been sent to atrace.
     92   trace_log->Flush(Bind(&NoOpOutputCallback, complete_event));
     93 }
     94 
     95 }  // namespace
     96 
     97 // These functions support Android systrace.py when 'webview' category is
     98 // traced. With the new adb_profile_chrome, we may have two phases:
     99 // - before WebView is ready for combined tracing, we can use adb_profile_chrome
    100 //   to trace android categories other than 'webview' and chromium categories.
    101 //   In this way we can avoid the conflict between StartATrace/StopATrace and
    102 //   the intents.
    103 // - TODO(wangxianzhu): after WebView is ready for combined tracing, remove
    104 //   StartATrace, StopATrace and SendToATrace, and perhaps send Java traces
    105 //   directly to atrace in trace_event_binding.cc.
    106 
    107 void TraceLog::StartATrace() {
    108   if (g_atrace_fd != -1)
    109     return;
    110 
    111   g_atrace_fd = HANDLE_EINTR(open(kATraceMarkerFile, O_WRONLY));
    112   if (g_atrace_fd == -1) {
    113     PLOG(WARNING) << "Couldn't open " << kATraceMarkerFile;
    114     return;
    115   }
    116   TraceConfig trace_config;
    117   trace_config.SetTraceRecordMode(RECORD_CONTINUOUSLY);
    118   SetEnabled(trace_config, TraceLog::RECORDING_MODE);
    119 }
    120 
    121 void TraceLog::StopATrace() {
    122   if (g_atrace_fd == -1)
    123     return;
    124 
    125   close(g_atrace_fd);
    126   g_atrace_fd = -1;
    127 
    128   // TraceLog::Flush() requires the current thread to have a message loop, but
    129   // this thread called from Java may not have one, so flush in another thread.
    130   Thread end_chrome_tracing_thread("end_chrome_tracing");
    131   WaitableEvent complete_event(WaitableEvent::ResetPolicy::AUTOMATIC,
    132                                WaitableEvent::InitialState::NOT_SIGNALED);
    133   end_chrome_tracing_thread.Start();
    134   end_chrome_tracing_thread.task_runner()->PostTask(
    135       FROM_HERE, base::Bind(&EndChromeTracing, Unretained(this),
    136                             Unretained(&complete_event)));
    137   complete_event.Wait();
    138 }
    139 
    140 void TraceEvent::SendToATrace() {
    141   if (g_atrace_fd == -1)
    142     return;
    143 
    144   const char* category_group =
    145       TraceLog::GetCategoryGroupName(category_group_enabled_);
    146 
    147   switch (phase_) {
    148     case TRACE_EVENT_PHASE_BEGIN:
    149       WriteEvent('B', category_group, name_, id_,
    150                  arg_names_, arg_types_, arg_values_, convertable_values_,
    151                  flags_);
    152       break;
    153 
    154     case TRACE_EVENT_PHASE_COMPLETE:
    155       WriteEvent(duration_.ToInternalValue() == -1 ? 'B' : 'E',
    156                  category_group, name_, id_,
    157                  arg_names_, arg_types_, arg_values_, convertable_values_,
    158                  flags_);
    159       break;
    160 
    161     case TRACE_EVENT_PHASE_END:
    162       // Though a single 'E' is enough, here append pid, name and
    163       // category_group etc. So that unpaired events can be found easily.
    164       WriteEvent('E', category_group, name_, id_,
    165                  arg_names_, arg_types_, arg_values_, convertable_values_,
    166                  flags_);
    167       break;
    168 
    169     case TRACE_EVENT_PHASE_INSTANT:
    170       // Simulate an instance event with a pair of begin/end events.
    171       WriteEvent('B', category_group, name_, id_,
    172                  arg_names_, arg_types_, arg_values_, convertable_values_,
    173                  flags_);
    174       WriteToATrace(g_atrace_fd, "E", 1);
    175       break;
    176 
    177     case TRACE_EVENT_PHASE_COUNTER:
    178       for (int i = 0; i < kTraceMaxNumArgs && arg_names_[i]; ++i) {
    179         DCHECK(arg_types_[i] == TRACE_VALUE_TYPE_INT);
    180         std::string out = base::StringPrintf(
    181             "C|%d|%s-%s", getpid(), name_, arg_names_[i]);
    182         if (flags_ & TRACE_EVENT_FLAG_HAS_ID)
    183           StringAppendF(&out, "-%" PRIx64, static_cast<uint64_t>(id_));
    184         StringAppendF(&out, "|%d|%s",
    185                       static_cast<int>(arg_values_[i].as_int), category_group);
    186         WriteToATrace(g_atrace_fd, out.c_str(), out.size());
    187       }
    188       break;
    189 
    190     default:
    191       // Do nothing.
    192       break;
    193   }
    194 }
    195 
    196 void TraceLog::AddClockSyncMetadataEvent() {
    197   int atrace_fd = HANDLE_EINTR(open(kATraceMarkerFile, O_WRONLY | O_APPEND));
    198   if (atrace_fd == -1) {
    199     PLOG(WARNING) << "Couldn't open " << kATraceMarkerFile;
    200     return;
    201   }
    202 
    203   // Android's kernel trace system has a trace_marker feature: this is a file on
    204   // debugfs that takes the written data and pushes it onto the trace
    205   // buffer. So, to establish clock sync, we write our monotonic clock into that
    206   // trace buffer.
    207   double now_in_seconds = (TimeTicks::Now() - TimeTicks()).InSecondsF();
    208   std::string marker = StringPrintf(
    209       "trace_event_clock_sync: parent_ts=%f\n", now_in_seconds);
    210   WriteToATrace(atrace_fd, marker.c_str(), marker.size());
    211   close(atrace_fd);
    212 }
    213 
    214 }  // namespace trace_event
    215 }  // namespace base
    216