oci: join crio-conmon for cgroupfs

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

vendor/github.com/containerd/cgroups/cpuset.go

@@ -0,0 +1,139 @@
+package cgroups
+
+import (
+	"bytes"
+	"fmt"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+)
+
+func NewCputset(root string) *cpusetController {
+	return &cpusetController{
+		root: filepath.Join(root, string(Cpuset)),
+	}
+}
+
+type cpusetController struct {
+	root string
+}
+
+func (c *cpusetController) Name() Name {
+	return Cpuset
+}
+
+func (c *cpusetController) Path(path string) string {
+	return filepath.Join(c.root, path)
+}
+
+func (c *cpusetController) Create(path string, resources *specs.LinuxResources) error {
+	if err := c.ensureParent(c.Path(path), c.root); err != nil {
+		return err
+	}
+	if err := os.MkdirAll(c.Path(path), defaultDirPerm); err != nil {
+		return err
+	}
+	if err := c.copyIfNeeded(c.Path(path), filepath.Dir(c.Path(path))); err != nil {
+		return err
+	}
+	if resources.CPU != nil {
+		for _, t := range []struct {
+			name  string
+			value *string
+		}{
+			{
+				name:  "cpus",
+				value: &resources.CPU.Cpus,
+			},
+			{
+				name:  "mems",
+				value: &resources.CPU.Mems,
+			},
+		} {
+			if t.value != nil {
+				if err := ioutil.WriteFile(
+					filepath.Join(c.Path(path), fmt.Sprintf("cpuset.%s", t.name)),
+					[]byte(*t.value),
+					defaultFilePerm,
+				); err != nil {
+					return err
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func (c *cpusetController) getValues(path string) (cpus []byte, mems []byte, err error) {
+	if cpus, err = ioutil.ReadFile(filepath.Join(path, "cpuset.cpus")); err != nil && !os.IsNotExist(err) {
+		return
+	}
+	if mems, err = ioutil.ReadFile(filepath.Join(path, "cpuset.mems")); err != nil && !os.IsNotExist(err) {
+		return
+	}
+	return cpus, mems, nil
+}
+
+// ensureParent makes sure that the parent directory of current is created
+// and populated with the proper cpus and mems files copied from
+// it's parent.
+func (c *cpusetController) ensureParent(current, root string) error {
+	parent := filepath.Dir(current)
+	if _, err := filepath.Rel(root, parent); err != nil {
+		return nil
+	}
+	// Avoid infinite recursion.
+	if parent == current {
+		return fmt.Errorf("cpuset: cgroup parent path outside cgroup root")
+	}
+	if cleanPath(parent) != root {
+		if err := c.ensureParent(parent, root); err != nil {
+			return err
+		}
+	}
+	if err := os.MkdirAll(current, defaultDirPerm); err != nil {
+		return err
+	}
+	return c.copyIfNeeded(current, parent)
+}
+
+// copyIfNeeded copies the cpuset.cpus and cpuset.mems from the parent
+// directory to the current directory if the file's contents are 0
+func (c *cpusetController) copyIfNeeded(current, parent string) error {
+	var (
+		err                      error
+		currentCpus, currentMems []byte
+		parentCpus, parentMems   []byte
+	)
+	if currentCpus, currentMems, err = c.getValues(current); err != nil {
+		return err
+	}
+	if parentCpus, parentMems, err = c.getValues(parent); err != nil {
+		return err
+	}
+	if isEmpty(currentCpus) {
+		if err := ioutil.WriteFile(
+			filepath.Join(current, "cpuset.cpus"),
+			parentCpus,
+			defaultFilePerm,
+		); err != nil {
+			return err
+		}
+	}
+	if isEmpty(currentMems) {
+		if err := ioutil.WriteFile(
+			filepath.Join(current, "cpuset.mems"),
+			parentMems,
+			defaultFilePerm,
+		); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func isEmpty(b []byte) bool {
+	return len(bytes.Trim(b, "\n")) == 0
+}