1 files changed, 65 insertions, 0 deletions
diff --git a/vendor/github.com/containerd/cgroups/v1.go b/vendor/github.com/containerd/cgroups/v1.go
new file mode 100644
index 000000000..f6608f7c7
--- /dev/null
+++ b/vendor/github.com/containerd/cgroups/v1.go
@@ -0,0 +1,65 @@
+package cgroups
+
+import (
+	"bufio"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+)
+
+// V1 returns all the groups in the default cgroups mountpoint in a single hierarchy
+func V1() ([]Subsystem, error) {
+	root, err := v1MountPoint()
+	if err != nil {
+		return nil, err
+	}
+	subsystems, err := defaults(root)
+	if err != nil {
+		return nil, err
+	}
+	var enabled []Subsystem
+	for _, s := range pathers(subsystems) {
+		// check and remove the default groups that do not exist
+		if _, err := os.Lstat(s.Path("/")); err == nil {
+			enabled = append(enabled, s)
+		}
+	}
+	return enabled, nil
+}
+
+// v1MountPoint returns the mount point where the cgroup
+// mountpoints are mounted in a single hiearchy
+func v1MountPoint() (string, error) {
+	f, err := os.Open("/proc/self/mountinfo")
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	scanner := bufio.NewScanner(f)
+	for scanner.Scan() {
+		if err := scanner.Err(); err != nil {
+			return "", err
+		}
+		var (
+			text   = scanner.Text()
+			fields = strings.Split(text, " ")
+			// safe as mountinfo encodes mountpoints with spaces as \040.
+			index               = strings.Index(text, " - ")
+			postSeparatorFields = strings.Fields(text[index+3:])
+			numPostFields       = len(postSeparatorFields)
+		)
+		// this is an error as we can't detect if the mount is for "cgroup"
+		if numPostFields == 0 {
+			return "", fmt.Errorf("Found no fields post '-' in %q", text)
+		}
+		if postSeparatorFields[0] == "cgroup" {
+			// check that the mount is properly formated.
+			if numPostFields < 3 {
+				return "", fmt.Errorf("Error found less than 3 fields post '-' in %q", text)
+			}
+			return filepath.Dir(fields[4]), nil
+		}
+	}
+	return "", ErrMountPointNotExist
+}