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/*
* Copyright (C) 2019 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.
*/
//#define LOG_NDEBUG 0
#define LOG_TAG "libprocessgroup"
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <pwd.h>
#include <sys/mman.h>
#include <sys/mount.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <time.h>
#include <unistd.h>
#include <regex>
#include <android-base/file.h>
#include <android-base/logging.h>
#include <android-base/properties.h>
#include <android-base/stringprintf.h>
#include <android-base/unique_fd.h>
#include <cgroup_map.h>
#include <json/reader.h>
#include <json/value.h>
#include <processgroup/processgroup.h>
using android::base::GetBoolProperty;
using android::base::StringPrintf;
using android::base::unique_fd;
static constexpr const char* CGROUP_PROCS_FILE = "/cgroup.procs";
static constexpr const char* CGROUP_TASKS_FILE = "/tasks";
static constexpr const char* CGROUP_TASKS_FILE_V2 = "/cgroup.tasks";
uint32_t CgroupController::version() const {
CHECK(HasValue());
return ACgroupController_getVersion(controller_);
}
const char* CgroupController::name() const {
CHECK(HasValue());
return ACgroupController_getName(controller_);
}
const char* CgroupController::path() const {
CHECK(HasValue());
return ACgroupController_getPath(controller_);
}
bool CgroupController::HasValue() const {
return controller_ != nullptr;
}
bool CgroupController::IsUsable() {
if (!HasValue()) return false;
if (state_ == UNKNOWN) {
if (__builtin_available(android 30, *)) {
uint32_t flags = ACgroupController_getFlags(controller_);
state_ = (flags & CGROUPRC_CONTROLLER_FLAG_MOUNTED) != 0 ? USABLE : MISSING;
} else {
state_ = access(GetProcsFilePath("", 0, 0).c_str(), F_OK) == 0 ? USABLE : MISSING;
}
}
return state_ == USABLE;
}
std::string CgroupController::GetTasksFilePath(const std::string& rel_path) const {
std::string tasks_path = path();
if (!rel_path.empty()) {
tasks_path += "/" + rel_path;
}
return (version() == 1) ? tasks_path + CGROUP_TASKS_FILE : tasks_path + CGROUP_TASKS_FILE_V2;
}
std::string CgroupController::GetProcsFilePath(const std::string& rel_path, uid_t uid,
pid_t pid) const {
std::string proc_path(path());
proc_path.append("/").append(rel_path);
proc_path = regex_replace(proc_path, std::regex("<uid>"), std::to_string(uid));
proc_path = regex_replace(proc_path, std::regex("<pid>"), std::to_string(pid));
return proc_path.append(CGROUP_PROCS_FILE);
}
bool CgroupController::GetTaskGroup(int tid, std::string* group) const {
std::string file_name = StringPrintf("/proc/%d/cgroup", tid);
std::string content;
if (!android::base::ReadFileToString(file_name, &content)) {
PLOG(ERROR) << "Failed to read " << file_name;
return false;
}
// if group is null and tid exists return early because
// user is not interested in cgroup membership
if (group == nullptr) {
return true;
}
std::string cg_tag;
if (version() == 2) {
cg_tag = "0::";
} else {
cg_tag = StringPrintf(":%s:", name());
}
size_t start_pos = content.find(cg_tag);
if (start_pos == std::string::npos) {
return false;
}
start_pos += cg_tag.length() + 1; // skip '/'
size_t end_pos = content.find('\n', start_pos);
if (end_pos == std::string::npos) {
*group = content.substr(start_pos, std::string::npos);
} else {
*group = content.substr(start_pos, end_pos - start_pos);
}
return true;
}
CgroupMap::CgroupMap() {
if (!LoadRcFile()) {
LOG(ERROR) << "CgroupMap::LoadRcFile called for [" << getpid() << "] failed";
}
}
CgroupMap& CgroupMap::GetInstance() {
// Deliberately leak this object to avoid a race between destruction on
// process exit and concurrent access from another thread.
static auto* instance = new CgroupMap;
return *instance;
}
bool CgroupMap::LoadRcFile() {
if (!loaded_) {
loaded_ = (ACgroupFile_getVersion() != 0);
}
return loaded_;
}
void CgroupMap::Print() const {
if (!loaded_) {
LOG(ERROR) << "CgroupMap::Print called for [" << getpid()
<< "] failed, RC file was not initialized properly";
return;
}
LOG(INFO) << "File version = " << ACgroupFile_getVersion();
LOG(INFO) << "File controller count = " << ACgroupFile_getControllerCount();
LOG(INFO) << "Mounted cgroups:";
auto controller_count = ACgroupFile_getControllerCount();
for (uint32_t i = 0; i < controller_count; ++i) {
const ACgroupController* controller = ACgroupFile_getController(i);
if (__builtin_available(android 30, *)) {
LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
<< ACgroupController_getVersion(controller) << " path "
<< ACgroupController_getPath(controller) << " flags "
<< ACgroupController_getFlags(controller);
} else {
LOG(INFO) << "\t" << ACgroupController_getName(controller) << " ver "
<< ACgroupController_getVersion(controller) << " path "
<< ACgroupController_getPath(controller);
}
}
}
CgroupController CgroupMap::FindController(const std::string& name) const {
if (!loaded_) {
LOG(ERROR) << "CgroupMap::FindController called for [" << getpid()
<< "] failed, RC file was not initialized properly";
return CgroupController(nullptr);
}
auto controller_count = ACgroupFile_getControllerCount();
for (uint32_t i = 0; i < controller_count; ++i) {
const ACgroupController* controller = ACgroupFile_getController(i);
if (name == ACgroupController_getName(controller)) {
return CgroupController(controller);
}
}
return CgroupController(nullptr);
}
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