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/*
* 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 <string>
#include <utility>
#include <android-base/file.h>
#include <android-base/logging.h>
#include "histogram_logger.h"
#include "uptime_parser.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;
// The following code (till function exit) is a debug test to ensure the
// validity of the file mtime value, i.e., to check that the record file
// mtime values are not changed once set.
// TODO(jhawkins): Remove this code.
std::string content;
if (!android::base::ReadFileToString(path, &content)) {
PLOG(ERROR) << "Failed to read " << path;
return false;
}
// Ignore existing bootstat records (which do not contain file content).
if (!content.empty()) {
int32_t value = std::stoi(content);
bootstat::LogHistogram("bootstat_mtime_matches_content", value == *uptime);
}
return true;
}
} // namespace
BootEventRecordStore::BootEventRecordStore() {
SetStorePath(BOOTSTAT_DATA_DIR);
}
void BootEventRecordStore::AddBootEvent(const std::string& event) {
AddBootEventWithValue(event, bootstat::ParseUptime());
}
// The implementation of AddBootEventValue makes use of the mtime file
// attribute to store the value associated with a boot event in order to
// optimize on-disk size requirements and small-file thrashing.
void BootEventRecordStore::AddBootEventWithValue(
const std::string& event, int32_t value) {
std::string record_path = GetBootEventPath(event);
int record_fd = creat(record_path.c_str(), S_IRUSR | S_IWUSR);
if (record_fd == -1) {
PLOG(ERROR) << "Failed to create " << record_path;
return;
}
// Writing the value as content in the record file is a debug measure to
// ensure the validity of the file mtime value, i.e., to check that the record
// file mtime values are not changed once set.
// TODO(jhawkins): Remove this block.
if (!android::base::WriteStringToFd(std::to_string(value), record_fd)) {
PLOG(ERROR) << "Failed to write value to " << record_path;
close(record_fd);
return;
}
// Fill out the stat structure for |record_path| in order to get the atime to
// set in the utime() call.
struct stat file_stat;
if (stat(record_path.c_str(), &file_stat) == -1) {
PLOG(ERROR) << "Failed to read " << record_path;
close(record_fd);
return;
}
// Set the |modtime| of the file to store the value of the boot event while
// preserving the |actime| (as read by stat).
struct utimbuf times = {/* actime */ file_stat.st_atime, /* modtime */ value};
if (utime(record_path.c_str(), ×) == -1) {
PLOG(ERROR) << "Failed to set mtime for " << record_path;
close(record_fd);
return;
}
close(record_fd);
}
bool BootEventRecordStore::GetBootEvent(
const std::string& event, BootEventRecord* record) const {
CHECK_NE(static_cast<BootEventRecord*>(nullptr), record);
CHECK(!event.empty());
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;
return false;
}
*record = std::make_pair(event, uptime);
return true;
}
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;
BootEventRecord record;
if (!GetBootEvent(event, &record)) {
LOG(ERROR) << "Failed to parse boot time event: " << event;
continue;
}
events.push_back(record);
}
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;
}
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