virtcontainers: resourcecontrol: Add skeleton for Darwin

Cgroups do not exist on Darwin, so use an empty implementation for
resourcecontrol for the time being. In the process, ensure that the
utilized cgroup handling (ie, isSystemdCgroup) is kept in general file,
since we use this to help assess/constrain the container spec we pass to
the guest.

Fixes: #6051

Signed-off-by: Samuel Ortiz <s.ortiz@apple.com>
Signed-off-by: Eric Ernst <eric_ernst@apple.com>

src/runtime/pkg/resourcecontrol/cgroups_darwin.go

@@ -0,0 +1,86 @@
+// Copyright (c) 2023 Apple Inc.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+package resourcecontrol
+
+import (
+	"errors"
+
+	"github.com/opencontainers/runtime-spec/specs-go"
+)
+
+type DarwinResourceController struct{}
+
+func RenameCgroupPath(path string) (string, error) {
+	return "", errors.New("RenameCgroupPath not supported on Darwin")
+}
+
+func NewResourceController(path string, resources *specs.LinuxResources) (ResourceController, error) {
+	return &DarwinResourceController{}, nil
+}
+
+func NewSandboxResourceController(path string, resources *specs.LinuxResources, sandboxCgroupOnly bool) (ResourceController, error) {
+	return &DarwinResourceController{}, nil
+}
+
+func LoadResourceController(path string) (ResourceController, error) {
+	return &DarwinResourceController{}, nil
+}
+
+func (c *DarwinResourceController) Delete() error {
+	return nil
+}
+
+func (c *DarwinResourceController) Stat() (interface{}, error) {
+	return nil, nil
+}
+
+func (c *DarwinResourceController) AddProcess(pid int, subsystems ...string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) AddThread(pid int, subsystems ...string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) AddTask(pid int, subsystems ...string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) Update(resources *specs.LinuxResources) error {
+	return nil
+}
+
+func (c *DarwinResourceController) MoveTo(path string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) ID() string {
+	return ""
+}
+
+func (c *DarwinResourceController) Parent() string {
+	return ""
+}
+
+func (c *DarwinResourceController) Type() ResourceControllerType {
+	return DarwinResourceControllerType
+}
+
+func (c *DarwinResourceController) AddDevice(deviceHostPath string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) RemoveDevice(deviceHostPath string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) UpdateCpuSet(cpuset, memset string) error {
+	return nil
+}
+
+func (c *DarwinResourceController) Path() string {
+	return ""
+}

src/runtime/pkg/resourcecontrol/controller.go

@@ -26,6 +26,7 @@ type ResourceControllerType string
 
 const (
 	LinuxCgroups                 ResourceControllerType = "cgroups"
+	DarwinResourceControllerType ResourceControllerType = "darwin"
 )
 
 // String converts a resource type to a string.

src/runtime/pkg/resourcecontrol/utils.go

@@ -19,6 +19,9 @@ var (
 	ErrCgroupMode = errors.New("cgroup controller type error")
 )
 
+// DefaultResourceControllerID runtime-determined location in the cgroups hierarchy.
+const DefaultResourceControllerID = "/vc"
+
 func DeviceToCgroupDeviceRule(device string) (*devices.Rule, error) {
 	var st unix.Stat_t
 	deviceRule := devices.Rule{

src/runtime/pkg/resourcecontrol/utils_linux.go

@@ -17,9 +17,6 @@ import (
 	"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
 )
 
-// DefaultResourceControllerID runtime-determined location in the cgroups hierarchy.
-const DefaultResourceControllerID = "/vc"
-
 // ValidCgroupPathV1 returns a valid cgroup path for cgroup v1.
 // see https://github.com/opencontainers/runtime-spec/blob/master/config-linux.md#cgroups-path
 func ValidCgroupPathV1(path string, systemdCgroup bool) (string, error) {