Initial cgroupfs support for subcontainers

Allow creation and management of subcontainers through cgroupfs
directory syscalls. Also add a mechanism to specify a default root
container to start new jobs in.

This implements the filesystem support for subcontainers, but doesn't
implement hierarchical resource accounting or task migration.

PiperOrigin-RevId: 390254870

1 files changed, 16 insertions, 2 deletions

diff --git a/test/util/cgroup_util.cc b/test/util/cgroup_util.cc
index 977993f41..df3c57b87 100644
--- a/test/util/cgroup_util.cc
+++ b/test/util/cgroup_util.cc
@@ -25,12 +25,26 @@
 namespace gvisor {
 namespace testing {
 
-Cgroup::Cgroup(std::string_view path) : cgroup_path_(path) {
+Cgroup::Cgroup(absl::string_view path) : cgroup_path_(path) {
   id_ = ++Cgroup::next_id_;
   std::cerr << absl::StreamFormat("[cg#%d] <= %s", id_, cgroup_path_)
             << std::endl;
 }
 
+PosixErrorOr<Cgroup> Cgroup::RecursivelyCreate(absl::string_view path) {
+  RETURN_IF_ERRNO(RecursivelyCreateDir(path));
+  return Cgroup(path);
+}
+
+PosixErrorOr<Cgroup> Cgroup::Create(absl::string_view path) {
+  RETURN_IF_ERRNO(Mkdir(path));
+  return Cgroup(path);
+}
+
+PosixErrorOr<Cgroup> Cgroup::CreateChild(absl::string_view name) const {
+  return Cgroup::Create(JoinPath(Path(), name));
+}
+
 PosixErrorOr<std::string> Cgroup::ReadControlFile(
     absl::string_view name) const {
   std::string buf;
@@ -93,7 +107,7 @@ PosixErrorOr<absl::flat_hash_set<pid_t>> Cgroup::ParsePIDList(
     absl::string_view data) const {
   absl::flat_hash_set<pid_t> res;
   std::vector<absl::string_view> lines = absl::StrSplit(data, '\n');
-  for (const std::string_view& line : lines) {
+  for (const absl::string_view& line : lines) {
     if (line.empty()) {
       continue;
     }