1 files changed, 392 insertions, 0 deletions
diff --git a/vendor/github.com/containerd/cgroups/utils.go b/vendor/github.com/containerd/cgroups/utils.go
new file mode 100644
index 000000000..217138975
--- /dev/null
+++ b/vendor/github.com/containerd/cgroups/utils.go
@@ -0,0 +1,392 @@
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package cgroups
+
+import (
+	"bufio"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"os"
+	"path/filepath"
+	"strconv"
+	"strings"
+	"sync"
+	"syscall"
+	"time"
+
+	units "github.com/docker/go-units"
+	specs "github.com/opencontainers/runtime-spec/specs-go"
+	"golang.org/x/sys/unix"
+)
+
+var (
+	nsOnce    sync.Once
+	inUserNS  bool
+	checkMode sync.Once
+	cgMode    CGMode
+)
+
+const unifiedMountpoint = "/sys/fs/cgroup"
+
+// CGMode is the cgroups mode of the host system
+type CGMode int
+
+const (
+	// Unavailable cgroup mountpoint
+	Unavailable CGMode = iota
+	// Legacy cgroups v1
+	Legacy
+	// Hybrid with cgroups v1 and v2 controllers mounted
+	Hybrid
+	// Unified with only cgroups v2 mounted
+	Unified
+)
+
+// Mode returns the cgroups mode running on the host
+func Mode() CGMode {
+	checkMode.Do(func() {
+		var st unix.Statfs_t
+		if err := unix.Statfs(unifiedMountpoint, &st); err != nil {
+			cgMode = Unavailable
+			return
+		}
+		switch st.Type {
+		case unix.CGROUP2_SUPER_MAGIC:
+			cgMode = Unified
+		default:
+			cgMode = Legacy
+			if err := unix.Statfs(filepath.Join(unifiedMountpoint, "unified"), &st); err != nil {
+				return
+			}
+			if st.Type == unix.CGROUP2_SUPER_MAGIC {
+				cgMode = Hybrid
+			}
+		}
+	})
+	return cgMode
+}
+
+// RunningInUserNS detects whether we are currently running in a user namespace.
+// Copied from github.com/lxc/lxd/shared/util.go
+func RunningInUserNS() bool {
+	nsOnce.Do(func() {
+		file, err := os.Open("/proc/self/uid_map")
+		if err != nil {
+			// This kernel-provided file only exists if user namespaces are supported
+			return
+		}
+		defer file.Close()
+
+		buf := bufio.NewReader(file)
+		l, _, err := buf.ReadLine()
+		if err != nil {
+			return
+		}
+
+		line := string(l)
+		var a, b, c int64
+		fmt.Sscanf(line, "%d %d %d", &a, &b, &c)
+
+		/*
+		 * We assume we are in the initial user namespace if we have a full
+		 * range - 4294967295 uids starting at uid 0.
+		 */
+		if a == 0 && b == 0 && c == 4294967295 {
+			return
+		}
+		inUserNS = true
+	})
+	return inUserNS
+}
+
+// defaults returns all known groups
+func defaults(root string) ([]Subsystem, error) {
+	h, err := NewHugetlb(root)
+	if err != nil && !os.IsNotExist(err) {
+		return nil, err
+	}
+	s := []Subsystem{
+		NewNamed(root, "systemd"),
+		NewFreezer(root),
+		NewPids(root),
+		NewNetCls(root),
+		NewNetPrio(root),
+		NewPerfEvent(root),
+		NewCpuset(root),
+		NewCpu(root),
+		NewCpuacct(root),
+		NewMemory(root),
+		NewBlkio(root),
+		NewRdma(root),
+	}
+	// only add the devices cgroup if we are not in a user namespace
+	// because modifications are not allowed
+	if !RunningInUserNS() {
+		s = append(s, NewDevices(root))
+	}
+	// add the hugetlb cgroup if error wasn't due to missing hugetlb
+	// cgroup support on the host
+	if err == nil {
+		s = append(s, h)
+	}
+	return s, nil
+}
+
+// remove will remove a cgroup path handling EAGAIN and EBUSY errors and
+// retrying the remove after a exp timeout
+func remove(path string) error {
+	delay := 10 * time.Millisecond
+	for i := 0; i < 5; i++ {
+		if i != 0 {
+			time.Sleep(delay)
+			delay *= 2
+		}
+		if err := os.RemoveAll(path); err == nil {
+			return nil
+		}
+	}
+	return fmt.Errorf("cgroups: unable to remove path %q", path)
+}
+
+// readPids will read all the pids of processes or tasks in a cgroup by the provided path
+func readPids(path string, subsystem Name, pType procType) ([]Process, error) {
+	f, err := os.Open(filepath.Join(path, pType))
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	var (
+		out []Process
+		s   = bufio.NewScanner(f)
+	)
+	for s.Scan() {
+		if t := s.Text(); t != "" {
+			pid, err := strconv.Atoi(t)
+			if err != nil {
+				return nil, err
+			}
+			out = append(out, Process{
+				Pid:       pid,
+				Subsystem: subsystem,
+				Path:      path,
+			})
+		}
+	}
+	if err := s.Err(); err != nil {
+		// failed to read all pids?
+		return nil, err
+	}
+	return out, nil
+}
+
+func hugePageSizes() ([]string, error) {
+	var (
+		pageSizes []string
+		sizeList  = []string{"B", "KB", "MB", "GB", "TB", "PB"}
+	)
+	files, err := ioutil.ReadDir("/sys/kernel/mm/hugepages")
+	if err != nil {
+		return nil, err
+	}
+	for _, st := range files {
+		nameArray := strings.Split(st.Name(), "-")
+		pageSize, err := units.RAMInBytes(nameArray[1])
+		if err != nil {
+			return nil, err
+		}
+		pageSizes = append(pageSizes, units.CustomSize("%g%s", float64(pageSize), 1024.0, sizeList))
+	}
+	return pageSizes, nil
+}
+
+func readUint(path string) (uint64, error) {
+	v, err := ioutil.ReadFile(path)
+	if err != nil {
+		return 0, err
+	}
+	return parseUint(strings.TrimSpace(string(v)), 10, 64)
+}
+
+func parseUint(s string, base, bitSize int) (uint64, error) {
+	v, err := strconv.ParseUint(s, base, bitSize)
+	if err != nil {
+		intValue, intErr := strconv.ParseInt(s, base, bitSize)
+		// 1. Handle negative values greater than MinInt64 (and)
+		// 2. Handle negative values lesser than MinInt64
+		if intErr == nil && intValue < 0 {
+			return 0, nil
+		} else if intErr != nil &&
+			intErr.(*strconv.NumError).Err == strconv.ErrRange &&
+			intValue < 0 {
+			return 0, nil
+		}
+		return 0, err
+	}
+	return v, nil
+}
+
+func parseKV(raw string) (string, uint64, error) {
+	parts := strings.Fields(raw)
+	switch len(parts) {
+	case 2:
+		v, err := parseUint(parts[1], 10, 64)
+		if err != nil {
+			return "", 0, err
+		}
+		return parts[0], v, nil
+	default:
+		return "", 0, ErrInvalidFormat
+	}
+}
+
+// ParseCgroupFile parses the given cgroup file, typically /proc/self/cgroup
+// or /proc/<pid>/cgroup, into a map of subsystems to cgroup paths, e.g.
+//   "cpu": "/user.slice/user-1000.slice"
+//   "pids": "/user.slice/user-1000.slice"
+// etc.
+//
+// The resulting map does not have an element for cgroup v2 unified hierarchy.
+// Use ParseCgroupFileUnified to get the unified path.
+func ParseCgroupFile(path string) (map[string]string, error) {
+	x, _, err := ParseCgroupFileUnified(path)
+	return x, err
+}
+
+// ParseCgroupFileUnified returns legacy subsystem paths as the first value,
+// and returns the unified path as the second value.
+func ParseCgroupFileUnified(path string) (map[string]string, string, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, "", err
+	}
+	defer f.Close()
+	return parseCgroupFromReaderUnified(f)
+}
+
+func parseCgroupFromReaderUnified(r io.Reader) (map[string]string, string, error) {
+	var (
+		cgroups = make(map[string]string)
+		unified = ""
+		s       = bufio.NewScanner(r)
+	)
+	for s.Scan() {
+		var (
+			text  = s.Text()
+			parts = strings.SplitN(text, ":", 3)
+		)
+		if len(parts) < 3 {
+			return nil, unified, fmt.Errorf("invalid cgroup entry: %q", text)
+		}
+		for _, subs := range strings.Split(parts[1], ",") {
+			if subs == "" {
+				unified = parts[2]
+			} else {
+				cgroups[subs] = parts[2]
+			}
+		}
+	}
+	if err := s.Err(); err != nil {
+		return nil, unified, err
+	}
+	return cgroups, unified, nil
+}
+
+func getCgroupDestination(subsystem string) (string, error) {
+	f, err := os.Open("/proc/self/mountinfo")
+	if err != nil {
+		return "", err
+	}
+	defer f.Close()
+	s := bufio.NewScanner(f)
+	for s.Scan() {
+		fields := strings.Split(s.Text(), " ")
+		if len(fields) < 10 {
+			// broken mountinfo?
+			continue
+		}
+		if fields[len(fields)-3] != "cgroup" {
+			continue
+		}
+		for _, opt := range strings.Split(fields[len(fields)-1], ",") {
+			if opt == subsystem {
+				return fields[3], nil
+			}
+		}
+	}
+	if err := s.Err(); err != nil {
+		return "", err
+	}
+	return "", ErrNoCgroupMountDestination
+}
+
+func pathers(subystems []Subsystem) []pather {
+	var out []pather
+	for _, s := range subystems {
+		if p, ok := s.(pather); ok {
+			out = append(out, p)
+		}
+	}
+	return out
+}
+
+func initializeSubsystem(s Subsystem, path Path, resources *specs.LinuxResources) error {
+	if c, ok := s.(creator); ok {
+		p, err := path(s.Name())
+		if err != nil {
+			return err
+		}
+		if err := c.Create(p, resources); err != nil {
+			return err
+		}
+	} else if c, ok := s.(pather); ok {
+		p, err := path(s.Name())
+		if err != nil {
+			return err
+		}
+		// do the default create if the group does not have a custom one
+		if err := os.MkdirAll(c.Path(p), defaultDirPerm); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func cleanPath(path string) string {
+	if path == "" {
+		return ""
+	}
+	path = filepath.Clean(path)
+	if !filepath.IsAbs(path) {
+		path, _ = filepath.Rel(string(os.PathSeparator), filepath.Clean(string(os.PathSeparator)+path))
+	}
+	return path
+}
+
+func retryingWriteFile(path string, data []byte, mode os.FileMode) error {
+	// Retry writes on EINTR; see:
+	//    https://github.com/golang/go/issues/38033
+	for {
+		err := ioutil.WriteFile(path, data, mode)
+		if err == nil {
+			return nil
+		} else if !errors.Is(err, syscall.EINTR) {
+			return err
+		}
+	}
+}