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// Copyright 2017 The Crashpad Authors. All rights reserved.
//
// 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 "util/linux/proc_stat_reader.h"
#include <stdio.h>
#include <time.h>
#include <unistd.h>
#include "base/files/file_path.h"
#include "base/logging.h"
#include "base/stl_util.h"
#include "util/file/file_io.h"
#include "util/misc/lexing.h"
#include "util/misc/time.h"
namespace crashpad {
namespace {
long GetClockTicksPerSecond() {
long clock_ticks_per_s = sysconf(_SC_CLK_TCK);
if (clock_ticks_per_s <= 0) {
PLOG(ERROR) << "sysconf";
}
return clock_ticks_per_s;
}
} // namespace
ProcStatReader::ProcStatReader()
: contents_(), third_column_position_(0), initialized_() {}
ProcStatReader::~ProcStatReader() {}
bool ProcStatReader::Initialize(PtraceConnection* connection, pid_t tid) {
INITIALIZATION_STATE_SET_INITIALIZING(initialized_);
char path[32];
snprintf(path, base::size(path), "/proc/%d/stat", tid);
if (!connection->ReadFileContents(base::FilePath(path), &contents_)) {
return false;
}
// The first column is process ID and the second column is the executable name
// in parentheses. This class only cares about columns after the second, so
// find the start of the third here and save it for later.
// The executable name may have parentheses itself, so find the end of the
// second column by working backwards to find the last closing parens.
size_t stat_pos = contents_.rfind(')');
if (stat_pos == std::string::npos) {
LOG(ERROR) << "format error";
return false;
}
third_column_position_ = contents_.find(' ', stat_pos);
if (third_column_position_ == std::string::npos ||
++third_column_position_ >= contents_.size()) {
LOG(ERROR) << "format error";
return false;
}
INITIALIZATION_STATE_SET_VALID(initialized_);
return true;
}
bool ProcStatReader::UserCPUTime(timeval* user_time) const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
return ReadTimeAtIndex(13, user_time);
}
bool ProcStatReader::SystemCPUTime(timeval* system_time) const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
return ReadTimeAtIndex(14, system_time);
}
bool ProcStatReader::StartTime(const timeval& boot_time,
timeval* start_time) const {
INITIALIZATION_STATE_DCHECK_VALID(initialized_);
timeval time_after_boot;
if (!ReadTimeAtIndex(21, &time_after_boot)) {
return false;
}
timeradd(&boot_time, &time_after_boot, start_time);
return true;
}
bool ProcStatReader::FindColumn(int col_index, const char** column) const {
size_t position = third_column_position_;
for (int index = 2; index < col_index; ++index) {
position = contents_.find(' ', position);
if (position == std::string::npos) {
break;
}
++position;
}
if (position >= contents_.size()) {
LOG(ERROR) << "format error";
return false;
}
*column = &contents_[position];
return true;
}
bool ProcStatReader::ReadTimeAtIndex(int index, timeval* time_val) const {
const char* ticks_ptr;
if (!FindColumn(index, &ticks_ptr)) {
return false;
}
uint64_t ticks;
if (!AdvancePastNumber<uint64_t>(&ticks_ptr, &ticks)) {
LOG(ERROR) << "format error";
return false;
}
static long clock_ticks_per_s = GetClockTicksPerSecond();
if (clock_ticks_per_s <= 0) {
return false;
}
time_val->tv_sec = ticks / clock_ticks_per_s;
time_val->tv_usec = (ticks % clock_ticks_per_s) *
(static_cast<long>(1E6) / clock_ticks_per_s);
return true;
}
} // namespace crashpad