system/core: Add initial implementation of the bootstat command.

The bootstat command enables the measurement and logging of boot time
metrics
for GMS devices.

BUG:21724738
Change-Id: I331456dd38a60fb4ef24a4d5320909dbad30db66
diff --git a/bootstat/bootstat.cpp b/bootstat/bootstat.cpp
new file mode 100644
index 0000000..a4cbf4e
--- /dev/null
+++ b/bootstat/bootstat.cpp
@@ -0,0 +1,144 @@
+/*
+ * Copyright (C) 2016 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+// The bootstat command provides options to persist boot events with the current
+// timestamp, dump the persisted events, and log all events to EventLog to be
+// uploaded to Android log storage via Tron.
+
+//#define LOG_TAG "bootstat"
+
+#include <unistd.h>
+#include <cstddef>
+#include <cstdio>
+#include <memory>
+#include <string>
+#include <base/logging.h>
+#include <log/log.h>
+#include "boot_event_record_store.h"
+#include "event_log_list_builder.h"
+
+namespace {
+
+// Builds an EventLog buffer named |event| containing |data| and writes
+// the log into the Tron histogram logs.
+void LogBootEvent(const std::string& event, int32_t data) {
+  LOG(INFO) << "Logging boot time: " << event << " " << data;
+
+  EventLogListBuilder log_builder;
+  log_builder.Append(event);
+  log_builder.Append(data);
+
+  std::unique_ptr<uint8_t[]> log;
+  size_t size;
+  log_builder.Release(&log, &size);
+
+  android_bWriteLog(HISTOGRAM_LOG_TAG, log.get(), size);
+}
+
+// Scans the boot event record store for record files and logs each boot event
+// via EventLog.
+void LogBootEvents() {
+  BootEventRecordStore boot_event_store;
+
+  auto events = boot_event_store.GetAllBootEvents();
+  for (auto i = events.cbegin(); i != events.cend(); ++i) {
+    LogBootEvent(i->first, i->second);
+  }
+}
+
+void PrintBootEvents() {
+  printf("Boot events:\n");
+  printf("------------\n");
+
+  BootEventRecordStore boot_event_store;
+  auto events = boot_event_store.GetAllBootEvents();
+  for (auto i = events.cbegin(); i != events.cend(); ++i) {
+    printf("%s\t%d\n", i->first.c_str(), i->second);
+  }
+}
+
+void ShowHelp(const char *cmd) {
+  fprintf(stderr, "Usage: %s [options]\n", cmd);
+  fprintf(stderr,
+          "options include:\n"
+          "  -d              Dump the boot event records to the console.\n"
+          "  -h              Show this help.\n"
+          "  -l              Log all metrics to logstorage.\n"
+          "  -r              Record the timestamp of a named boot event.\n");
+}
+
+// Constructs a readable, printable string from the givencommand line
+// arguments.
+std::string GetCommandLine(int argc, char **argv) {
+  std::string cmd;
+  for (int i = 0; i < argc; ++i) {
+    cmd += argv[i];
+    cmd += " ";
+  }
+
+  return cmd;
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  android::base::InitLogging(argv);
+
+  const std::string cmd_line = GetCommandLine(argc, argv);
+  LOG(INFO) << "Service started: " << cmd_line;
+
+  int opt = 0;
+  while ((opt = getopt(argc, argv, "hlpr:")) != -1) {
+    switch (opt) {
+      case 'h': {
+        ShowHelp(argv[0]);
+        break;
+      }
+
+      case 'l': {
+        LogBootEvents();
+        break;
+      }
+
+      case 'p': {
+        PrintBootEvents();
+        break;
+      }
+
+      case 'r': {
+        // |optarg| is an external variable set by getopt representing
+        // the option argument.
+        const char* event = optarg;
+
+        BootEventRecordStore boot_event_store;
+        boot_event_store.AddBootEvent(event);
+        break;
+      }
+
+      default: {
+        DCHECK_EQ(opt, '?');
+
+        // |optopt| is an external variable set by getopt representing
+        // the value of the invalid option.
+        LOG(ERROR) << "Invalid option: " << optopt;
+        ShowHelp(argv[0]);
+        return EXIT_FAILURE;
+      }
+    }
+  }
+
+  return 0;
+}