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// Copyright 2014 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/chromeos/power/freezer_cgroup_process_manager.h"
#include <string>
#include "base/bind.h"
#include "base/bind_helpers.h"
#include "base/files/file_util.h"
#include "base/logging.h"
#include "base/macros.h"
#include "base/sequenced_task_runner.h"
#include "base/strings/string_number_conversions.h"
#include "content/public/browser/browser_thread.h"
namespace chromeos {
namespace {
const char kFreezerPath[] = "/sys/fs/cgroup/freezer/chrome_renderers";
const char kToBeFrozen[] = "to_be_frozen";
const char kFreezerState[] = "freezer.state";
const char kCgroupProcs[] = "cgroup.procs";
const char kFreezeCommand[] = "FROZEN";
const char kThawCommand[] = "THAWED";
} // namespace
class FreezerCgroupProcessManager::FileWorker {
public:
// Called on UI thread.
explicit FileWorker(scoped_refptr<base::SequencedTaskRunner> file_thread)
: ui_thread_(content::BrowserThread::GetMessageLoopProxyForThread(
content::BrowserThread::UI)),
file_thread_(file_thread) {
DCHECK(ui_thread_->RunsTasksOnCurrentThread());
}
// Called on FILE thread.
virtual ~FileWorker() { DCHECK(file_thread_->RunsTasksOnCurrentThread()); }
void Start() {
DCHECK(file_thread_->RunsTasksOnCurrentThread());
default_control_path_ = base::FilePath(kFreezerPath).Append(kCgroupProcs);
to_be_frozen_control_path_ = base::FilePath(kFreezerPath)
.AppendASCII(kToBeFrozen)
.AppendASCII(kCgroupProcs);
to_be_frozen_state_path_ = base::FilePath(kFreezerPath)
.AppendASCII(kToBeFrozen)
.AppendASCII(kFreezerState);
enabled_ = base::PathIsWritable(default_control_path_) &&
base::PathIsWritable(to_be_frozen_control_path_) &&
base::PathIsWritable(to_be_frozen_state_path_);
if (!enabled_) {
LOG(WARNING) << "Cgroup freezer does not exist or is not writable. "
<< "Unable to freeze renderer processes.";
}
}
void SetShouldFreezeRenderer(base::ProcessHandle handle, bool frozen) {
DCHECK(file_thread_->RunsTasksOnCurrentThread());
WriteCommandToFile(base::IntToString(handle),
frozen ? to_be_frozen_control_path_
: default_control_path_);
}
void FreezeRenderers() {
DCHECK(file_thread_->RunsTasksOnCurrentThread());
if (!enabled_) {
LOG(ERROR) << "Attempting to freeze renderers when the freezer cgroup is "
<< "not available.";
return;
}
WriteCommandToFile(kFreezeCommand, to_be_frozen_state_path_);
}
void ThawRenderers(ResultCallback callback) {
DCHECK(file_thread_->RunsTasksOnCurrentThread());
if (!enabled_) {
LOG(ERROR) << "Attempting to thaw renderers when the freezer cgroup is "
<< "not available.";
return;
}
bool result = WriteCommandToFile(kThawCommand, to_be_frozen_state_path_);
ui_thread_->PostTask(FROM_HERE, base::Bind(callback, result));
}
void CheckCanFreezeRenderers(ResultCallback callback) {
DCHECK(file_thread_->RunsTasksOnCurrentThread());
ui_thread_->PostTask(FROM_HERE, base::Bind(callback, enabled_));
}
private:
bool WriteCommandToFile(const std::string& command,
const base::FilePath& file) {
int bytes = base::WriteFile(file, command.c_str(), command.size());
if (bytes == -1) {
PLOG(ERROR) << "Writing " << command << " to " << file.value()
<< " failed";
return false;
} else if (bytes != static_cast<int>(command.size())) {
LOG(ERROR) << "Only wrote " << bytes << " byte(s) when writing "
<< command << " to " << file.value();
return false;
}
return true;
}
scoped_refptr<base::SequencedTaskRunner> ui_thread_;
scoped_refptr<base::SequencedTaskRunner> file_thread_;
// Control path for the cgroup that is not frozen.
base::FilePath default_control_path_;
// Control and state paths for the cgroup whose processes will be frozen.
base::FilePath to_be_frozen_control_path_;
base::FilePath to_be_frozen_state_path_;
bool enabled_;
DISALLOW_COPY_AND_ASSIGN(FileWorker);
};
FreezerCgroupProcessManager::FreezerCgroupProcessManager()
: file_thread_(content::BrowserThread::GetMessageLoopProxyForThread(
content::BrowserThread::FILE)),
file_worker_(new FileWorker(file_thread_)) {
file_thread_->PostTask(FROM_HERE,
base::Bind(&FileWorker::Start,
base::Unretained(file_worker_.get())));
}
FreezerCgroupProcessManager::~FreezerCgroupProcessManager() {
file_thread_->DeleteSoon(FROM_HERE, file_worker_.release());
}
void FreezerCgroupProcessManager::SetShouldFreezeRenderer(
base::ProcessHandle handle,
bool frozen) {
file_thread_->PostTask(FROM_HERE,
base::Bind(&FileWorker::SetShouldFreezeRenderer,
base::Unretained(file_worker_.get()),
handle, frozen));
}
void FreezerCgroupProcessManager::FreezeRenderers() {
file_thread_->PostTask(FROM_HERE,
base::Bind(&FileWorker::FreezeRenderers,
base::Unretained(file_worker_.get())));
}
void FreezerCgroupProcessManager::ThawRenderers(ResultCallback callback) {
file_thread_->PostTask(FROM_HERE,
base::Bind(&FileWorker::ThawRenderers,
base::Unretained(file_worker_.get()),
callback));
}
void FreezerCgroupProcessManager::CheckCanFreezeRenderers(
ResultCallback callback) {
file_thread_->PostTask(FROM_HERE,
base::Bind(&FileWorker::CheckCanFreezeRenderers,
base::Unretained(file_worker_.get()),
callback));
}
} // namespace chromeos
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