Merge "libprocessgroup: make sure SetupCgroups is called once and only by init" (7b2187c3) · Commits · e / os / android_system_core

libprocessgroup/cgroup_map.cpp

+19 −3

Original line number	Diff line number	Diff line
		@@ -229,7 +229,9 @@ static bool SetupCgroup(const CgroupDescriptor&) {

		static bool WriteRcFile(const std::map<std::string, CgroupDescriptor>& descriptors) {
		std::string cgroup_rc_path = StringPrintf("%s/%s", CGROUPS_RC_DIR, CgroupMap::CGROUPS_RC_FILE);
		unique_fd fd(TEMP_FAILURE_RETRY(open(cgroup_rc_path.c_str(),
		// Let init keep the FD open to prevent file mappings from becoming invalid
		// in case the file gets deleted somehow
		static unique_fd fd(TEMP_FAILURE_RETRY(open(cgroup_rc_path.c_str(),
		O_CREAT \| O_WRONLY \| O_TRUNC \| O_CLOEXEC,
		S_IRUSR \| S_IRGRP \| S_IROTH)));
		if (fd < 0) {
		@@ -412,6 +414,19 @@ 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
		static bool setup_done = false;
		if (setup_done) {
		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";
		@@ -449,6 +464,7 @@ bool CgroupMap::SetupCgroups() {
		return false;
		}

		setup_done = true;
		return true;
		}