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/Android.mk b/bootstat/Android.mk
new file mode 100644
index 0000000..348db88
--- /dev/null
+++ b/bootstat/Android.mk
@@ -0,0 +1,137 @@
+#
+# 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.
+#
+
+LOCAL_PATH := $(call my-dir)
+
+bootstat_c_includes := external/gtest/include
+
+bootstat_lib_src_files := \
+ boot_event_record_store.cpp \
+ event_log_list_builder.cpp
+
+bootstat_src_files := \
+ bootstat.cpp
+
+bootstat_test_src_files := \
+ boot_event_record_store_test.cpp \
+ event_log_list_builder_test.cpp \
+ testrunner.cpp
+
+bootstat_shared_libs := \
+ libbase \
+ liblog
+
+bootstat_cflags := \
+ -Wall \
+ -Wextra \
+ -Werror
+
+bootstat_cppflags := \
+ -Wno-non-virtual-dtor
+
+bootstat_debug_cflags := \
+ $(bootstat_cflags) \
+ -UNDEBUG
+
+# 524291 corresponds to sysui_histogram, from
+# frameworks/base/core/java/com/android/internal/logging/EventLogTags.logtags
+bootstat_cflags += -DHISTOGRAM_LOG_TAG=524291
+
+
+# bootstat static library
+# -----------------------------------------------------------------------------
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := libbootstat
+LOCAL_CFLAGS := $(bootstat_cflags)
+LOCAL_CPPFLAGS := $(bootstat_cppflags)
+LOCAL_C_INCLUDES := $(bootstat_c_includes)
+LOCAL_SHARED_LIBRARIES := $(bootstat_shared_libs)
+LOCAL_SRC_FILES := $(bootstat_lib_src_files)
+
+include $(BUILD_STATIC_LIBRARY)
+
+# bootstat static library, debug
+# -----------------------------------------------------------------------------
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := libbootstat_debug
+LOCAL_CFLAGS := $(bootstat_cflags)
+LOCAL_CPPFLAGS := $(bootstat_debug_cppflags)
+LOCAL_C_INCLUDES := $(bootstat_c_includes)
+LOCAL_SHARED_LIBRARIES := $(bootstat_shared_libs)
+LOCAL_SRC_FILES := $(bootstat_lib_src_files)
+
+include $(BUILD_STATIC_LIBRARY)
+
+# bootstat host static library, debug
+# -----------------------------------------------------------------------------
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := libbootstat_host_debug
+LOCAL_CFLAGS := $(bootstat_debug_cflags)
+LOCAL_CPPFLAGS := $(bootstat_cppflags)
+LOCAL_C_INCLUDES := $(bootstat_c_includes)
+LOCAL_SHARED_LIBRARIES := $(bootstat_shared_libs)
+LOCAL_SRC_FILES := $(bootstat_lib_src_files)
+
+include $(BUILD_HOST_STATIC_LIBRARY)
+
+# bootstat binary
+# -----------------------------------------------------------------------------
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := bootstat
+LOCAL_CFLAGS := $(bootstat_cflags)
+LOCAL_CPPFLAGS := $(bootstat_cppflags)
+LOCAL_C_INCLUDES := $(bootstat_c_includes)
+LOCAL_SHARED_LIBRARIES := $(bootstat_shared_libs)
+LOCAL_STATIC_LIBRARIES := libbootstat
+LOCAL_SRC_FILES := $(bootstat_src_files)
+
+include $(BUILD_EXECUTABLE)
+
+# Native tests
+# -----------------------------------------------------------------------------
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := bootstat_tests
+LOCAL_CFLAGS := $(bootstat_tests_cflags)
+LOCAL_CPPFLAGS := $(bootstat_cppflags)
+LOCAL_SHARED_LIBRARIES := $(bootstat_shared_libs)
+LOCAL_STATIC_LIBRARIES := libbootstat_debug libgmock
+LOCAL_SRC_FILES := $(bootstat_test_src_files)
+
+include $(BUILD_NATIVE_TEST)
+
+# Host native tests
+# -----------------------------------------------------------------------------
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := bootstat_tests
+LOCAL_CFLAGS := $(bootstat_tests_cflags)
+LOCAL_CPPFLAGS := $(bootstat_cppflags)
+LOCAL_SHARED_LIBRARIES := $(bootstat_shared_libs)
+LOCAL_STATIC_LIBRARIES := libbootstat_host_debug libgmock_host
+LOCAL_SRC_FILES := $(bootstat_test_src_files)
+
+include $(BUILD_HOST_NATIVE_TEST)
diff --git a/bootstat/README.md b/bootstat/README.md
new file mode 100644
index 0000000..b494951
--- /dev/null
+++ b/bootstat/README.md
@@ -0,0 +1,47 @@
+# bootstat #
+
+The bootstat command records boot events (e.g., `firmware_loaded`,
+`boot_complete`) and the relative time at which these events occurred. The
+command also aggregates boot event metrics locally and logs the metrics for
+analysis.
+
+ Usage: bootstat [options]
+ options include:
+ -d Dump the boot event records to the console.
+ -h Show this help.
+ -l Log all metrics to logstorage.
+ -r Record the relative time of a named boot event.
+
+## Relative time ##
+
+The timestamp recorded by bootstat is the uptime of the system, i.e., the
+number of seconds since the system booted.
+
+## Recording boot events ##
+
+To record the relative time of an event during the boot phase, call `bootstat`
+with the `-r` option and the name of the boot event.
+
+ $ bootstat -r boot_complete
+
+The relative time at which the command runs is recorded along with the name of
+the boot event to be persisted.
+
+## Logging boot events ##
+
+To log the persisted boot events, call `bootstat` with the `-l` option.
+
+ $ bootstat -l
+
+bootstat logs all boot events recorded using the `-r` option to the EventLog
+using the Tron histogram. On GMS devices these logs are uploaded via Clearcut
+for aggregation and analysis.
+
+## Printing boot events ##
+
+To print the set of persisted boot events, call `bootstat` with the `-p` option.
+
+ $ bootstat -p
+ Boot events:
+ ------------
+ boot_complete 71
\ No newline at end of file
diff --git a/bootstat/boot_event_record_store.cpp b/bootstat/boot_event_record_store.cpp
new file mode 100644
index 0000000..0133f5b
--- /dev/null
+++ b/bootstat/boot_event_record_store.cpp
@@ -0,0 +1,116 @@
+/*
+ * 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.
+ */
+
+#include "boot_event_record_store.h"
+
+#include <dirent.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <utime.h>
+#include <cstdlib>
+#include <base/file.h>
+#include <base/logging.h>
+
+namespace {
+
+const char BOOTSTAT_DATA_DIR[] = "/data/misc/bootstat/";
+
+// Given a boot even record file at |path|, extracts the event's relative time
+// from the record into |uptime|.
+bool ParseRecordEventTime(const std::string& path, int32_t* uptime) {
+ DCHECK_NE(static_cast<int32_t*>(nullptr), uptime);
+
+ struct stat file_stat;
+ if (stat(path.c_str(), &file_stat) == -1) {
+ PLOG(ERROR) << "Failed to read " << path;
+ return false;
+ }
+
+ *uptime = file_stat.st_mtime;
+ return true;
+}
+
+} // namespace
+
+BootEventRecordStore::BootEventRecordStore() {
+ SetStorePath(BOOTSTAT_DATA_DIR);
+}
+
+void BootEventRecordStore::AddBootEvent(const std::string& name) {
+ std::string uptime_str;
+ if (!android::base::ReadFileToString("/proc/uptime", &uptime_str)) {
+ LOG(ERROR) << "Failed to read /proc/uptime";
+ }
+
+ std::string record_path = GetBootEventPath(name);
+ if (creat(record_path.c_str(), S_IRUSR | S_IWUSR) == -1) {
+ PLOG(ERROR) << "Failed to create " << record_path;
+ }
+
+ struct stat file_stat;
+ if (stat(record_path.c_str(), &file_stat) == -1) {
+ PLOG(ERROR) << "Failed to read " << record_path;
+ }
+
+ // Cast intentionally rounds down.
+ time_t uptime = static_cast<time_t>(strtod(uptime_str.c_str(), NULL));
+ struct utimbuf times = {file_stat.st_atime, uptime};
+ if (utime(record_path.c_str(), ×) == -1) {
+ PLOG(ERROR) << "Failed to set mtime for " << record_path;
+ }
+}
+
+std::vector<BootEventRecordStore::BootEventRecord> BootEventRecordStore::
+ GetAllBootEvents() const {
+ std::vector<BootEventRecord> events;
+
+ std::unique_ptr<DIR, decltype(&closedir)> dir(opendir(store_path_.c_str()), closedir);
+
+ // This case could happen due to external manipulation of the filesystem,
+ // so crash out if the record store doesn't exist.
+ CHECK_NE(static_cast<DIR*>(nullptr), dir.get());
+
+ struct dirent* entry;
+ while ((entry = readdir(dir.get())) != NULL) {
+ // Only parse regular files.
+ if (entry->d_type != DT_REG) {
+ continue;
+ }
+
+ const std::string event = entry->d_name;
+ const std::string record_path = GetBootEventPath(event);
+ int32_t uptime;
+ if (!ParseRecordEventTime(record_path, &uptime)) {
+ LOG(ERROR) << "Failed to parse boot time record: " << record_path;
+ continue;
+ }
+
+ events.push_back(std::make_pair(event, uptime));
+ }
+
+ return events;
+}
+
+void BootEventRecordStore::SetStorePath(const std::string& path) {
+ DCHECK_EQ('/', path.back());
+ store_path_ = path;
+}
+
+std::string BootEventRecordStore::GetBootEventPath(
+ const std::string& event) const {
+ DCHECK_EQ('/', store_path_.back());
+ return store_path_ + event;
+}
diff --git a/bootstat/boot_event_record_store.h b/bootstat/boot_event_record_store.h
new file mode 100644
index 0000000..efe1e43
--- /dev/null
+++ b/bootstat/boot_event_record_store.h
@@ -0,0 +1,61 @@
+/*
+ * 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.
+ */
+
+#ifndef BOOT_EVENT_RECORD_STORE_H_
+#define BOOT_EVENT_RECORD_STORE_H_
+
+#include <cstdint>
+#include <string>
+#include <utility>
+#include <vector>
+#include <base/macros.h>
+#include <gtest/gtest_prod.h>
+
+// BootEventRecordStore manages the persistence of boot events to the record
+// store and the retrieval of all boot event records from the store.
+class BootEventRecordStore {
+ public:
+ // A BootEventRecord consists of the event name and the timestamp the event
+ // occurred.
+ typedef std::pair<std::string, int32_t> BootEventRecord;
+
+ BootEventRecordStore();
+
+ // Persists the boot event named |name| in the record store.
+ void AddBootEvent(const std::string& name);
+
+ // Returns a list of all of the boot events persisted in the record store.
+ std::vector<BootEventRecord> GetAllBootEvents() const;
+
+ private:
+ // The tests call SetStorePath to override the default store location with a
+ // more test-friendly path.
+ FRIEND_TEST(BootEventRecordStoreTest, AddSingleBootEvent);
+ FRIEND_TEST(BootEventRecordStoreTest, AddMultipleBootEvents);
+
+ // Sets the filesystem path of the record store.
+ void SetStorePath(const std::string& path);
+
+ // Constructs the full path of the given boot |event|.
+ std::string GetBootEventPath(const std::string& event) const;
+
+ // The filesystem path of the record store.
+ std::string store_path_;
+
+ DISALLOW_COPY_AND_ASSIGN(BootEventRecordStore);
+};
+
+#endif // BOOT_EVENT_RECORD_STORE_H_
\ No newline at end of file
diff --git a/bootstat/boot_event_record_store_test.cpp b/bootstat/boot_event_record_store_test.cpp
new file mode 100644
index 0000000..56af0a6
--- /dev/null
+++ b/bootstat/boot_event_record_store_test.cpp
@@ -0,0 +1,156 @@
+/*
+ * 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.
+ */
+
+#include "boot_event_record_store.h"
+
+#include <dirent.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <cstdint>
+#include <cstdlib>
+#include <base/file.h>
+#include <base/test_utils.h>
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+
+using testing::UnorderedElementsAreArray;
+
+namespace {
+
+// Returns true if the time difference between |a| and |b| is no larger
+// than 10 seconds. This allow for a relatively large fuzz when comparing
+// two timestamps taken back-to-back.
+bool FuzzUptimeEquals(int32_t a, int32_t b) {
+ const int32_t FUZZ_SECONDS = 10;
+ return (abs(a - b) <= FUZZ_SECONDS);
+}
+
+// Returns the uptime as read from /proc/uptime, rounded down to an integer.
+int32_t ReadUptime() {
+ std::string uptime_str;
+ if (!android::base::ReadFileToString("/proc/uptime", &uptime_str)) {
+ return -1;
+ }
+
+ // Cast to int to round down.
+ return static_cast<int32_t>(strtod(uptime_str.c_str(), NULL));
+}
+
+// Recursively deletes the directory at |path|.
+void DeleteDirectory(const std::string& path) {
+ typedef std::unique_ptr<DIR, decltype(&closedir)> ScopedDIR;
+ ScopedDIR dir(opendir(path.c_str()), closedir);
+ ASSERT_NE(nullptr, dir.get());
+
+ struct dirent* entry;
+ while ((entry = readdir(dir.get())) != NULL) {
+ const std::string entry_name(entry->d_name);
+ if (entry_name == "." || entry_name == "..") {
+ continue;
+ }
+
+ const std::string entry_path = path + "/" + entry_name;
+ if (entry->d_type == DT_DIR) {
+ DeleteDirectory(entry_path);
+ } else {
+ unlink(entry_path.c_str());
+ }
+ }
+
+ rmdir(path.c_str());
+}
+
+class BootEventRecordStoreTest : public ::testing::Test {
+ public:
+ BootEventRecordStoreTest() {
+ store_path_ = std::string(store_dir_.path) + "/";
+ }
+
+ const std::string& GetStorePathForTesting() const {
+ return store_path_;
+ }
+
+ private:
+ void TearDown() {
+ // This removes the record store temporary directory even though
+ // TemporaryDir should already take care of it, but this method cleans up
+ // the test files added to the directory which prevent TemporaryDir from
+ // being able to remove the directory.
+ DeleteDirectory(store_path_);
+ }
+
+ // A scoped temporary directory. Using this abstraction provides creation of
+ // the directory and the path to the directory, which is stored in
+ // |store_path_|.
+ TemporaryDir store_dir_;
+
+ // The path to the temporary directory used by the BootEventRecordStore to
+ // persist records. The directory is created and destroyed for each test.
+ std::string store_path_;
+
+ DISALLOW_COPY_AND_ASSIGN(BootEventRecordStoreTest);
+};
+
+} // namespace
+
+TEST_F(BootEventRecordStoreTest, AddSingleBootEvent) {
+ BootEventRecordStore store;
+ store.SetStorePath(GetStorePathForTesting());
+
+ int32_t uptime = ReadUptime();
+ ASSERT_NE(-1, uptime);
+
+ store.AddBootEvent("cenozoic");
+
+ auto events = store.GetAllBootEvents();
+ ASSERT_EQ(1U, events.size());
+ EXPECT_EQ("cenozoic", events[0].first);
+ EXPECT_TRUE(FuzzUptimeEquals(uptime, events[0].second));
+}
+
+TEST_F(BootEventRecordStoreTest, AddMultipleBootEvents) {
+ BootEventRecordStore store;
+ store.SetStorePath(GetStorePathForTesting());
+
+ int32_t uptime = ReadUptime();
+ ASSERT_NE(-1, uptime);
+
+ store.AddBootEvent("cretaceous");
+ store.AddBootEvent("jurassic");
+ store.AddBootEvent("triassic");
+
+ const std::string EXPECTED_NAMES[] = {
+ "cretaceous",
+ "jurassic",
+ "triassic",
+ };
+
+ auto events = store.GetAllBootEvents();
+ ASSERT_EQ(3U, events.size());
+
+ std::vector<std::string> names;
+ std::vector<int32_t> timestamps;
+ for (auto i = events.begin(); i != events.end(); ++i) {
+ names.push_back(i->first);
+ timestamps.push_back(i->second);
+ }
+
+ EXPECT_THAT(names, UnorderedElementsAreArray(EXPECTED_NAMES));
+
+ for (auto i = timestamps.cbegin(); i != timestamps.cend(); ++i) {
+ EXPECT_TRUE(FuzzUptimeEquals(uptime, *i));
+ }
+}
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;
+}
diff --git a/bootstat/event_log_list_builder.cpp b/bootstat/event_log_list_builder.cpp
new file mode 100644
index 0000000..017a7c5
--- /dev/null
+++ b/bootstat/event_log_list_builder.cpp
@@ -0,0 +1,106 @@
+/*
+ * 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.
+ */
+
+#include "event_log_list_builder.h"
+
+#include <cinttypes>
+#include <string>
+#include <base/logging.h>
+#include <log/log.h>
+
+namespace {
+
+const size_t MAX_EVENT_PAYLOAD_SIZE = 512 - 1; // Leave room for final '\n'.
+const size_t EVENT_TYPE_SIZE = 1; // Size in bytes of the event type marker.
+
+} // namespace
+
+EventLogListBuilder::EventLogListBuilder()
+ : payload_count_(0),
+ payload_size_(0),
+ payload_(std::make_unique<uint8_t[]>(MAX_EVENT_PAYLOAD_SIZE)) {
+ memset(payload_.get(), 0, MAX_EVENT_PAYLOAD_SIZE);
+
+ // Set up the top-level EventLog data type.
+ AppendByte(EVENT_TYPE_LIST);
+
+ // Skip over the byte prepresenting the number of items in the list. This
+ // value is set in Release().
+ payload_size_++;
+}
+
+bool EventLogListBuilder::Append(int value) {
+ DCHECK_NE(static_cast<uint8_t*>(nullptr), payload_.get());
+
+ if (!IsSpaceAvailable(sizeof(value) + EVENT_TYPE_SIZE)) {
+ return false;
+ }
+
+ AppendByte(EVENT_TYPE_INT);
+ AppendData(&value, sizeof(value));
+
+ payload_count_++;
+ return true;
+}
+
+bool EventLogListBuilder::Append(const std::string& value) {
+ DCHECK_NE(static_cast<uint8_t*>(nullptr), payload_.get());
+
+ int len = value.length();
+ if (!IsSpaceAvailable(sizeof(len) + len)) {
+ return false;
+ }
+
+ AppendByte(EVENT_TYPE_STRING);
+ AppendData(&len, sizeof(len));
+ AppendData(value.c_str(), len);
+
+ payload_count_++;
+ return true;
+}
+
+void EventLogListBuilder::Release(std::unique_ptr<uint8_t[]>* log,
+ size_t* size) {
+ // Finalize the log payload.
+ payload_[1] = payload_count_;
+
+ // Return the log payload.
+ *size = payload_size_;
+ *log = std::move(payload_);
+}
+
+void EventLogListBuilder::AppendData(const void* data, size_t size) {
+ DCHECK_LT(payload_size_ + size, MAX_EVENT_PAYLOAD_SIZE);
+ memcpy(&payload_[payload_size_], data, size);
+ payload_size_ += size;
+}
+
+void EventLogListBuilder::AppendByte(uint8_t byte) {
+ DCHECK_LT(payload_size_ + sizeof(byte), MAX_EVENT_PAYLOAD_SIZE);
+ payload_[payload_size_++] = byte;
+}
+
+bool EventLogListBuilder::IsSpaceAvailable(size_t value_size) {
+ size_t space_needed = value_size + EVENT_TYPE_SIZE;
+ if (payload_size_ + space_needed > MAX_EVENT_PAYLOAD_SIZE) {
+ size_t remaining = MAX_EVENT_PAYLOAD_SIZE - payload_size_;
+ LOG(WARNING) << "Not enough space for value. remain=" <<
+ remaining << "; needed=" << space_needed;
+ return false;
+ }
+
+ return true;
+}
diff --git a/bootstat/event_log_list_builder.h b/bootstat/event_log_list_builder.h
new file mode 100644
index 0000000..52d623f
--- /dev/null
+++ b/bootstat/event_log_list_builder.h
@@ -0,0 +1,70 @@
+/*
+ * 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.
+ */
+
+#ifndef EVENT_LOG_LIST_BUILDER_H_
+#define EVENT_LOG_LIST_BUILDER_H_
+
+#include <cstdint>
+#include <memory>
+
+#include <base/macros.h>
+
+// EventLogListBuilder provides a mechanism to build an EventLog list
+// consisting of int and string EventLog values.
+//
+// NOTE: This class does not provide the ability to append an embedded list,
+// i.e., a list containing a list.
+class EventLogListBuilder {
+ public:
+ EventLogListBuilder();
+
+ // Append a single value of a specified type.
+ bool Append(int value);
+ bool Append(const std::string& value);
+
+ // Finalizes construction of the EventLog list and releases the data
+ // to the caller. Caller takes ownership of the payload. No further calls
+ // to append* may be made once the payload is acquired by the caller.
+ void Release(std::unique_ptr<uint8_t[]>* log, size_t* size);
+
+ private:
+ // Appends |data| of the given |size| to the payload.
+ void AppendData(const void* data, size_t size);
+
+ // Appends a single byte to the payload.
+ void AppendByte(uint8_t byte);
+
+ // Returns true iff the remaining capacity in |payload_| is large enough to
+ // accommodate |value_size| bytes. The space required to log the event type
+ // is included in the internal calculation so must not be passed in to
+ // |value_size|.
+ bool IsSpaceAvailable(size_t value_size);
+
+ // The number of items in the EventLog list.
+ size_t payload_count_;
+
+ // The size of the data stored in |payload_|. Used to track where to insert
+ // new data.
+ size_t payload_size_;
+
+ // The payload constructed by calls to log*. The payload may only contain
+ // MAX_EVENT_PAYLOAD (512) bytes.
+ std::unique_ptr<uint8_t[]> payload_;
+
+ DISALLOW_COPY_AND_ASSIGN(EventLogListBuilder);
+};
+
+ #endif // EVENT_LOG_LIST_BUILDER_H_
diff --git a/bootstat/event_log_list_builder_test.cpp b/bootstat/event_log_list_builder_test.cpp
new file mode 100644
index 0000000..affb4bf
--- /dev/null
+++ b/bootstat/event_log_list_builder_test.cpp
@@ -0,0 +1,113 @@
+/*
+ * 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.
+ */
+
+#include "event_log_list_builder.h"
+
+#include <inttypes.h>
+#include <gtest/gtest.h>
+#include <gmock/gmock.h>
+#include <log/log.h>
+
+using testing::ElementsAreArray;
+
+TEST(EventLogListBuilder, Empty) {
+ EventLogListBuilder builder;
+
+ const uint8_t EXPECTED_LOG[] = {
+ EVENT_TYPE_LIST,
+ 0, // Number of items in the list.
+ };
+
+ std::unique_ptr<uint8_t[]> log;
+ size_t size;
+ builder.Release(&log, &size);
+ EXPECT_EQ(2U, size);
+
+ uint8_t* log_data = log.get();
+ EXPECT_THAT(std::vector<uint8_t>(log_data, log_data + size),
+ ElementsAreArray(EXPECTED_LOG));
+}
+
+TEST(EventLogListBuilder, SingleInt) {
+ EventLogListBuilder builder;
+
+ const uint8_t EXPECTED_LOG[] = {
+ EVENT_TYPE_LIST,
+ 1, // Number of items in the list.
+ EVENT_TYPE_INT,
+ 42, 0, 0, 0, // 4 byte integer value.
+ };
+
+ builder.Append(42);
+
+ std::unique_ptr<uint8_t[]> log;
+ size_t size;
+ builder.Release(&log, &size);
+ EXPECT_EQ(7U, size);
+
+ uint8_t* log_data = log.get();
+ EXPECT_THAT(std::vector<uint8_t>(log_data, log_data + size),
+ ElementsAreArray(EXPECTED_LOG));
+}
+
+TEST(EventLogListBuilder, SingleString) {
+ EventLogListBuilder builder;
+
+ const uint8_t EXPECTED_LOG[] = {
+ EVENT_TYPE_LIST,
+ 1, // Number of items in the list.
+ EVENT_TYPE_STRING,
+ 5, 0, 0, 0, // 4 byte length of the string.
+ 'D', 'r', 'o', 'i', 'd',
+ };
+
+ builder.Append("Droid");
+
+ std::unique_ptr<uint8_t[]> log;
+ size_t size;
+ builder.Release(&log, &size);
+ EXPECT_EQ(12U, size);
+
+ uint8_t* log_data = log.get();
+ EXPECT_THAT(std::vector<uint8_t>(log_data, log_data + size),
+ ElementsAreArray(EXPECTED_LOG));
+}
+
+TEST(EventLogListBuilder, IntThenString) {
+ EventLogListBuilder builder;
+
+ const uint8_t EXPECTED_LOG[] = {
+ EVENT_TYPE_LIST,
+ 2, // Number of items in the list.
+ EVENT_TYPE_INT,
+ 42, 0, 0, 0, // 4 byte integer value.
+ EVENT_TYPE_STRING,
+ 5, 0, 0, 0, // 4 byte length of the string.
+ 'D', 'r', 'o', 'i', 'd',
+ };
+
+ builder.Append(42);
+ builder.Append("Droid");
+
+ std::unique_ptr<uint8_t[]> log;
+ size_t size;
+ builder.Release(&log, &size);
+ EXPECT_EQ(17U, size);
+
+ uint8_t* log_data = log.get();
+ EXPECT_THAT(std::vector<uint8_t>(log_data, log_data + size),
+ ElementsAreArray(EXPECTED_LOG));
+}
diff --git a/bootstat/testrunner.cpp b/bootstat/testrunner.cpp
new file mode 100644
index 0000000..ff8611e
--- /dev/null
+++ b/bootstat/testrunner.cpp
@@ -0,0 +1,24 @@
+/*
+ * 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.
+ */
+
+#include <base/logging.h>
+#include <gtest/gtest.h>
+
+int main(int argc, char** argv) {
+ ::testing::InitGoogleTest(&argc, argv);
+ android::base::InitLogging(argv, android::base::StderrLogger);
+ return RUN_ALL_TESTS();
+}