vendor: cadvisor v0.39.0

Main upgrades:
- github.com/opencontainers/runc v1.0.0-rc93
- github.com/containerd/containerd v1.4.4
- github.com/docker/docker v20.10.2
- github.com/mrunalp/fileutils v0.5.0
- github.com/opencontainers/selinux v1.8.0
- github.com/cilium/ebpf v0.2.0

vendor/github.com/opencontainers/runc/libcontainer/cgroups/v1_utils.go

@@ -1,16 +1,16 @@
 package cgroups
 
 import (
-	"bufio"
 	"errors"
 	"fmt"
-	"io"
 	"os"
 	"path/filepath"
 	"strings"
+	"sync"
 	"syscall"
 
 	securejoin "github.com/cyphar/filepath-securejoin"
+	"github.com/moby/sys/mountinfo"
 	"golang.org/x/sys/unix"
 )
 
@@ -23,7 +23,12 @@ const (
 )
 
 var (
-	errUnified = errors.New("not implemented for cgroup v2 unified hierarchy")
+	errUnified     = errors.New("not implemented for cgroup v2 unified hierarchy")
+	ErrV1NoUnified = errors.New("invalid configuration: cannot use unified on cgroup v1")
+
+	readMountinfoOnce sync.Once
+	readMountinfoErr  error
+	cgroupMountinfo   []*mountinfo.Info
 )
 
 type NotFoundError struct {
@@ -90,6 +95,21 @@ func tryDefaultPath(cgroupPath, subsystem string) string {
 	return path
 }
 
+// readCgroupMountinfo returns a list of cgroup v1 mounts (i.e. the ones
+// with fstype of "cgroup") for the current running process.
+//
+// The results are cached (to avoid re-reading mountinfo which is relatively
+// expensive), so it is assumed that cgroup mounts are not being changed.
+func readCgroupMountinfo() ([]*mountinfo.Info, error) {
+	readMountinfoOnce.Do(func() {
+		cgroupMountinfo, readMountinfoErr = mountinfo.GetMounts(
+			mountinfo.FSTypeFilter("cgroup"),
+		)
+	})
+
+	return cgroupMountinfo, readMountinfoErr
+}
+
 // https://www.kernel.org/doc/Documentation/cgroup-v1/cgroups.txt
 func FindCgroupMountpoint(cgroupPath, subsystem string) (string, error) {
 	if IsCgroup2UnifiedMode() {
@@ -110,56 +130,28 @@ func FindCgroupMountpointAndRoot(cgroupPath, subsystem string) (string, string,
 		return "", "", errUnified
 	}
 
-	// Avoid parsing mountinfo by checking if subsystem is valid/available.
-	if !isSubsystemAvailable(subsystem) {
-		return "", "", NewNotFoundError(subsystem)
-	}
-
-	f, err := os.Open("/proc/self/mountinfo")
+	mi, err := readCgroupMountinfo()
 	if err != nil {
 		return "", "", err
 	}
-	defer f.Close()
 
-	return findCgroupMountpointAndRootFromReader(f, cgroupPath, subsystem)
+	return findCgroupMountpointAndRootFromMI(mi, cgroupPath, subsystem)
 }
 
-func findCgroupMountpointAndRootFromReader(reader io.Reader, cgroupPath, subsystem string) (string, string, error) {
-	scanner := bufio.NewScanner(reader)
-	for scanner.Scan() {
-		txt := scanner.Text()
-		fields := strings.Fields(txt)
-		if len(fields) < 9 {
-			continue
-		}
-		if strings.HasPrefix(fields[4], cgroupPath) {
-			for _, opt := range strings.Split(fields[len(fields)-1], ",") {
+func findCgroupMountpointAndRootFromMI(mounts []*mountinfo.Info, cgroupPath, subsystem string) (string, string, error) {
+	for _, mi := range mounts {
+		if strings.HasPrefix(mi.Mountpoint, cgroupPath) {
+			for _, opt := range strings.Split(mi.VFSOptions, ",") {
 				if opt == subsystem {
-					return fields[4], fields[3], nil
+					return mi.Mountpoint, mi.Root, nil
 				}
 			}
 		}
 	}
-	if err := scanner.Err(); err != nil {
-		return "", "", err
-	}
 
 	return "", "", NewNotFoundError(subsystem)
 }
 
-func isSubsystemAvailable(subsystem string) bool {
-	if IsCgroup2UnifiedMode() {
-		panic("don't call isSubsystemAvailable from cgroupv2 code")
-	}
-
-	cgroups, err := ParseCgroupFile("/proc/self/cgroup")
-	if err != nil {
-		return false
-	}
-	_, avail := cgroups[subsystem]
-	return avail
-}
-
 func (m Mount) GetOwnCgroup(cgroups map[string]string) (string, error) {
 	if len(m.Subsystems) == 0 {
 		return "", fmt.Errorf("no subsystem for mount")
@@ -168,25 +160,15 @@ func (m Mount) GetOwnCgroup(cgroups map[string]string) (string, error) {
 	return getControllerPath(m.Subsystems[0], cgroups)
 }
 
-func getCgroupMountsHelper(ss map[string]bool, mi io.Reader, all bool) ([]Mount, error) {
+func getCgroupMountsHelper(ss map[string]bool, mounts []*mountinfo.Info, all bool) ([]Mount, error) {
 	res := make([]Mount, 0, len(ss))
-	scanner := bufio.NewScanner(mi)
 	numFound := 0
-	for scanner.Scan() && numFound < len(ss) {
-		txt := scanner.Text()
-		sepIdx := strings.Index(txt, " - ")
-		if sepIdx == -1 {
-			return nil, fmt.Errorf("invalid mountinfo format")
-		}
-		if txt[sepIdx+3:sepIdx+10] == "cgroup2" || txt[sepIdx+3:sepIdx+9] != "cgroup" {
-			continue
-		}
-		fields := strings.Split(txt, " ")
+	for _, mi := range mounts {
 		m := Mount{
-			Mountpoint: fields[4],
-			Root:       fields[3],
+			Mountpoint: mi.Mountpoint,
+			Root:       mi.Root,
 		}
-		for _, opt := range strings.Split(fields[len(fields)-1], ",") {
+		for _, opt := range strings.Split(mi.VFSOptions, ",") {
 			seen, known := ss[opt]
 			if !known || (!all && seen) {
 				continue
@@ -199,19 +181,18 @@ func getCgroupMountsHelper(ss map[string]bool, mi io.Reader, all bool) ([]Mount,
 		if len(m.Subsystems) > 0 || all {
 			res = append(res, m)
 		}
-	}
-	if err := scanner.Err(); err != nil {
-		return nil, err
+		if !all && numFound >= len(ss) {
+			break
+		}
 	}
 	return res, nil
 }
 
 func getCgroupMountsV1(all bool) ([]Mount, error) {
-	f, err := os.Open("/proc/self/mountinfo")
+	mi, err := readCgroupMountinfo()
 	if err != nil {
 		return nil, err
 	}
-	defer f.Close()
 
 	allSubsystems, err := ParseCgroupFile("/proc/self/cgroup")
 	if err != nil {
@@ -222,7 +203,8 @@ func getCgroupMountsV1(all bool) ([]Mount, error) {
 	for s := range allSubsystems {
 		allMap[s] = false
 	}
-	return getCgroupMountsHelper(allMap, f, all)
+
+	return getCgroupMountsHelper(allMap, mi, all)
 }
 
 // GetOwnCgroup returns the relative path to the cgroup docker is running in.