libprocessgroup: Move CgroupSetupCgroups() to libprocessgroup_setup am: 6f9ce2e548 (e7f9de2c) · Commits · e / os / android_system_core

init/Android.bp

+1 −0

Original line number	Diff line number	Diff line
		@@ -82,6 +82,7 @@ cc_defaults {
		"liblogwrap",
		"liblp",
		"libprocessgroup",
		"libprocessgroup_setup",
		"libselinux",
		"libutils",
		],

init/init.cpp

+1 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,7 @@
		#include <libavb/libavb.h>
		#include <libgsi/libgsi.h>
		#include <processgroup/processgroup.h>
		#include <processgroup/setup.h>
		#include <selinux/android.h>

		#ifndef RECOVERY

libprocessgroup/cgroup_map.cpp

+0 −271

Original line number	Diff line number	Diff line
		@@ -44,222 +44,10 @@ using android::base::GetBoolProperty;
		using android::base::StringPrintf;
		using android::base::unique_fd;

		static constexpr const char* CGROUPS_DESC_FILE = "/etc/cgroups.json";
		static constexpr const char* CGROUPS_DESC_VENDOR_FILE = "/vendor/etc/cgroups.json";

		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";

		static bool Mkdir(const std::string& path, mode_t mode, const std::string& uid,
		const std::string& gid) {
		if (mode == 0) {
		mode = 0755;
		}

		if (mkdir(path.c_str(), mode) != 0) {
		/* chmod in case the directory already exists */
		if (errno == EEXIST) {
		if (fchmodat(AT_FDCWD, path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
		// /acct is a special case when the directory already exists
		// TODO: check if file mode is already what we want instead of using EROFS
		if (errno != EROFS) {
		PLOG(ERROR) << "fchmodat() failed for " << path;
		return false;
		}
		}
		} else {
		PLOG(ERROR) << "mkdir() failed for " << path;
		return false;
		}
		}

		if (uid.empty()) {
		return true;
		}

		passwd* uid_pwd = getpwnam(uid.c_str());
		if (!uid_pwd) {
		PLOG(ERROR) << "Unable to decode UID for '" << uid << "'";
		return false;
		}

		uid_t pw_uid = uid_pwd->pw_uid;
		gid_t gr_gid = -1;
		if (!gid.empty()) {
		group* gid_pwd = getgrnam(gid.c_str());
		if (!gid_pwd) {
		PLOG(ERROR) << "Unable to decode GID for '" << gid << "'";
		return false;
		}
		gr_gid = gid_pwd->gr_gid;
		}

		if (lchown(path.c_str(), pw_uid, gr_gid) < 0) {
		PLOG(ERROR) << "lchown() failed for " << path;
		return false;
		}

		/* chown may have cleared S_ISUID and S_ISGID, chmod again */
		if (mode & (S_ISUID \| S_ISGID)) {
		if (fchmodat(AT_FDCWD, path.c_str(), mode, AT_SYMLINK_NOFOLLOW) != 0) {
		PLOG(ERROR) << "fchmodat() failed for " << path;
		return false;
		}
		}

		return true;
		}

		static bool ReadDescriptorsFromFile(const std::string& file_name,
		std::map<std::string, CgroupDescriptor>* descriptors) {
		std::vector<CgroupDescriptor> result;
		std::string json_doc;

		if (!android::base::ReadFileToString(file_name, &json_doc)) {
		PLOG(ERROR) << "Failed to read task profiles from " << file_name;
		return false;
		}

		Json::Reader reader;
		Json::Value root;
		if (!reader.parse(json_doc, root)) {
		LOG(ERROR) << "Failed to parse cgroups description: " << reader.getFormattedErrorMessages();
		return false;
		}

		if (root.isMember("Cgroups")) {
		const Json::Value& cgroups = root["Cgroups"];
		for (Json::Value::ArrayIndex i = 0; i < cgroups.size(); ++i) {
		std::string name = cgroups[i]["Controller"].asString();
		auto iter = descriptors->find(name);
		if (iter == descriptors->end()) {
		descriptors->emplace(name, CgroupDescriptor(1, name, cgroups[i]["Path"].asString(),
		std::strtoul(cgroups[i]["Mode"].asString().c_str(), 0, 8),
		cgroups[i]["UID"].asString(), cgroups[i]["GID"].asString()));
		} else {
		iter->second = CgroupDescriptor(1, name, cgroups[i]["Path"].asString(),
		std::strtoul(cgroups[i]["Mode"].asString().c_str(), 0, 8),
		cgroups[i]["UID"].asString(), cgroups[i]["GID"].asString());
		}
		}
		}

		if (root.isMember("Cgroups2")) {
		const Json::Value& cgroups2 = root["Cgroups2"];
		auto iter = descriptors->find(CGROUPV2_CONTROLLER_NAME);
		if (iter == descriptors->end()) {
		descriptors->emplace(CGROUPV2_CONTROLLER_NAME, CgroupDescriptor(2, CGROUPV2_CONTROLLER_NAME, cgroups2["Path"].asString(),
		std::strtoul(cgroups2["Mode"].asString().c_str(), 0, 8),
		cgroups2["UID"].asString(), cgroups2["GID"].asString()));
		} else {
		iter->second = CgroupDescriptor(2, CGROUPV2_CONTROLLER_NAME, cgroups2["Path"].asString(),
		std::strtoul(cgroups2["Mode"].asString().c_str(), 0, 8),
		cgroups2["UID"].asString(), cgroups2["GID"].asString());
		}
		}

		return true;
		}

		static bool ReadDescriptors(std::map<std::string, CgroupDescriptor>* descriptors) {
		// load system cgroup descriptors
		if (!ReadDescriptorsFromFile(CGROUPS_DESC_FILE, descriptors)) {
		return false;
		}

		// load vendor cgroup descriptors if the file exists
		if (!access(CGROUPS_DESC_VENDOR_FILE, F_OK) &&
		!ReadDescriptorsFromFile(CGROUPS_DESC_VENDOR_FILE, descriptors)) {
		return false;
		}

		return true;
		}

		// To avoid issues in sdk_mac build
		#if defined(__ANDROID__)

		static bool SetupCgroup(const CgroupDescriptor& descriptor) {
		const CgroupController* controller = descriptor.controller();

		// mkdir <path> [mode] [owner] [group]
		if (!Mkdir(controller->path(), descriptor.mode(), descriptor.uid(), descriptor.gid())) {
		LOG(ERROR) << "Failed to create directory for " << controller->name() << " cgroup";
		return false;
		}

		int result;
		if (controller->version() == 2) {
		result = mount("none", controller->path(), "cgroup2", MS_NODEV \| MS_NOEXEC \| MS_NOSUID,
		nullptr);
		} else {
		// Unfortunately historically cpuset controller was mounted using a mount command
		// different from all other controllers. This results in controller attributes not
		// to be prepended with controller name. For example this way instead of
		// /dev/cpuset/cpuset.cpus the attribute becomes /dev/cpuset/cpus which is what
		// the system currently expects.
		if (!strcmp(controller->name(), "cpuset")) {
		// mount cpuset none /dev/cpuset nodev noexec nosuid
		result = mount("none", controller->path(), controller->name(),
		MS_NODEV \| MS_NOEXEC \| MS_NOSUID, nullptr);
		} else {
		// mount cgroup none <path> nodev noexec nosuid <controller>
		result = mount("none", controller->path(), "cgroup", MS_NODEV \| MS_NOEXEC \| MS_NOSUID,
		controller->name());
		}
		}

		if (result < 0) {
		PLOG(ERROR) << "Failed to mount " << controller->name() << " cgroup";
		return false;
		}

		return true;
		}

		#else

		// Stubs for non-Android targets.
		static bool SetupCgroup(const CgroupDescriptor&) {
		return false;
		}

		#endif

		// WARNING: This function should be called only from SetupCgroups and only once.
		// It intentionally leaks an FD, so additional invocation will result in additional leak.
		static bool WriteRcFile(const std::map<std::string, CgroupDescriptor>& descriptors) {
		// WARNING: We are intentionally leaking the FD to keep the file open forever.
		// Let init keep the FD open to prevent file mappings from becoming invalid in
		// case the file gets deleted somehow.
		int fd = TEMP_FAILURE_RETRY(open(CGROUPS_RC_PATH, O_CREAT \| O_WRONLY \| O_TRUNC \| O_CLOEXEC,
		S_IRUSR \| S_IRGRP \| S_IROTH));
		if (fd < 0) {
		PLOG(ERROR) << "open() failed for " << CGROUPS_RC_PATH;
		return false;
		}

		CgroupFile fl;
		fl.version_ = CgroupFile::FILE_CURR_VERSION;
		fl.controller_count_ = descriptors.size();
		int ret = TEMP_FAILURE_RETRY(write(fd, &fl, sizeof(fl)));
		if (ret < 0) {
		PLOG(ERROR) << "write() failed for " << CGROUPS_RC_PATH;
		return false;
		}

		for (const auto& [name, descriptor] : descriptors) {
		ret = TEMP_FAILURE_RETRY(write(fd, descriptor.controller(), sizeof(CgroupController)));
		if (ret < 0) {
		PLOG(ERROR) << "write() failed for " << CGROUPS_RC_PATH;
		return false;
		}
		}

		return true;
		}

		CgroupController::CgroupController(uint32_t version, const std::string& name,
		const std::string& path) {
		version_ = version;
		@@ -319,11 +107,6 @@ bool CgroupController::GetTaskGroup(int tid, std::string* group) const {
		return true;
		}

		CgroupDescriptor::CgroupDescriptor(uint32_t version, const std::string& name,
		const std::string& path, mode_t mode, const std::string& uid,
		const std::string& gid)
		: controller_(version, name, path), mode_(mode), uid_(uid), gid_(gid) {}

		CgroupMap::CgroupMap() : cg_file_data_(nullptr), cg_file_size_(0) {
		if (!LoadRcFile()) {
		LOG(ERROR) << "CgroupMap::LoadRcFile called for [" << getpid() << "] failed";
		@@ -411,60 +194,6 @@ void CgroupMap::Print() const {
		}
		}

		bool CgroupMap::SetupCgroups() {
		std::map<std::string, CgroupDescriptor> descriptors;

		if (getpid() != 1) {
		LOG(ERROR) << "Cgroup setup can be done only by init process";
		return false;
		}

		// Make sure we do this only one time. No need for std::call_once because
		// init is a single-threaded process
		if (access(CGROUPS_RC_PATH, F_OK) == 0) {
		LOG(WARNING) << "Attempt to call SetupCgroups more than once";
		return true;
		}

		// load cgroups.json file
		if (!ReadDescriptors(&descriptors)) {
		LOG(ERROR) << "Failed to load cgroup description file";
		return false;
		}

		// setup cgroups
		for (const auto& [name, descriptor] : descriptors) {
		if (!SetupCgroup(descriptor)) {
		// issue a warning and proceed with the next cgroup
		// TODO: mark the descriptor as invalid and skip it in WriteRcFile()
		LOG(WARNING) << "Failed to setup " << name << " cgroup";
		}
		}

		// mkdir <CGROUPS_RC_DIR> 0711 system system
		if (!Mkdir(android::base::Dirname(CGROUPS_RC_PATH), 0711, "system", "system")) {
		LOG(ERROR) << "Failed to create directory for " << CGROUPS_RC_PATH << " file";
		return false;
		}

		// Generate <CGROUPS_RC_FILE> file which can be directly mmapped into
		// process memory. This optimizes performance, memory usage
		// and limits infrormation shared with unprivileged processes
		// to the minimum subset of information from cgroups.json
		if (!WriteRcFile(descriptors)) {
		LOG(ERROR) << "Failed to write " << CGROUPS_RC_PATH << " file";
		return false;
		}

		// chmod 0644 <CGROUPS_RC_PATH>
		if (fchmodat(AT_FDCWD, CGROUPS_RC_PATH, 0644, AT_SYMLINK_NOFOLLOW) < 0) {
		PLOG(ERROR) << "fchmodat() failed";
		return false;
		}

		return true;
		}

		const CgroupController* CgroupMap::FindController(const std::string& name) const {
		if (!cg_file_data_) {
		LOG(ERROR) << "CgroupMap::FindController called for [" << getpid()

libprocessgroup/cgroup_map.h

+0 −18

Original line number	Diff line number	Diff line
		@@ -46,24 +46,6 @@ class CgroupController {
		char path_[CGROUP_PATH_BUF_SZ];
		};

		// Complete controller description for mounting cgroups
		class CgroupDescriptor {
		public:
		CgroupDescriptor(uint32_t version, const std::string& name, const std::string& path,
		mode_t mode, const std::string& uid, const std::string& gid);

		const CgroupController* controller() const { return &controller_; }
		mode_t mode() const { return mode_; }
		std::string uid() const { return uid_; }
		std::string gid() const { return gid_; }

		private:
		CgroupController controller_;
		mode_t mode_;
		std::string uid_;
		std::string gid_;
		};

		struct CgroupFile {
		static constexpr uint32_t FILE_VERSION_1 = 1;
		static constexpr uint32_t FILE_CURR_VERSION = FILE_VERSION_1;

libprocessgroup/include/processgroup/processgroup.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -26,7 +26,6 @@ __BEGIN_DECLS
		static constexpr const char* CGROUPV2_CONTROLLER_NAME = "cgroup2";
		static constexpr const char* CGROUPS_RC_PATH = "/dev/cgroup_info/cgroup.rc";

		bool CgroupSetupCgroups();
		bool CgroupGetControllerPath(const std::string& cgroup_name, std::string* path);
		bool CgroupGetAttributePath(const std::string& attr_name, std::string* path);
		bool CgroupGetAttributePathForTask(const std::string& attr_name, int tid, std::string* path);