runc/libcontainer/factory_linux.go

451 lines
13 KiB
Go

// +build linux
package libcontainer
import (
"encoding/json"
"fmt"
"os"
"path/filepath"
"regexp"
"runtime/debug"
"strconv"
securejoin "github.com/cyphar/filepath-securejoin"
"github.com/moby/sys/mountinfo"
"github.com/opencontainers/runc/libcontainer/cgroups"
"github.com/opencontainers/runc/libcontainer/cgroups/fs"
"github.com/opencontainers/runc/libcontainer/cgroups/fs2"
"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/configs/validate"
"github.com/opencontainers/runc/libcontainer/intelrdt"
"github.com/opencontainers/runc/libcontainer/utils"
"github.com/pkg/errors"
"golang.org/x/sys/unix"
)
const (
stateFilename = "state.json"
execFifoFilename = "exec.fifo"
)
var idRegex = regexp.MustCompile(`^[\w+-\.]+$`)
// InitArgs returns an options func to configure a LinuxFactory with the
// provided init binary path and arguments.
func InitArgs(args ...string) func(*LinuxFactory) error {
return func(l *LinuxFactory) (err error) {
if len(args) > 0 {
// Resolve relative paths to ensure that its available
// after directory changes.
if args[0], err = filepath.Abs(args[0]); err != nil {
return newGenericError(err, ConfigInvalid)
}
}
l.InitArgs = args
return nil
}
}
func getUnifiedPath(paths map[string]string) string {
path := ""
for k, v := range paths {
if path == "" {
path = v
} else if v != path {
panic(errors.Errorf("expected %q path to be unified path %q, got %q", k, path, v))
}
}
// can be empty
if path != "" {
if filepath.Clean(path) != path || !filepath.IsAbs(path) {
panic(errors.Errorf("invalid dir path %q", path))
}
}
return path
}
func systemdCgroupV2(l *LinuxFactory, rootless bool) error {
l.NewCgroupsManager = func(config *configs.Cgroup, paths map[string]string) cgroups.Manager {
return systemd.NewUnifiedManager(config, getUnifiedPath(paths), rootless)
}
return nil
}
// SystemdCgroups is an options func to configure a LinuxFactory to return
// containers that use systemd to create and manage cgroups.
func SystemdCgroups(l *LinuxFactory) error {
if !systemd.IsRunningSystemd() {
return fmt.Errorf("systemd not running on this host, can't use systemd as cgroups manager")
}
if cgroups.IsCgroup2UnifiedMode() {
return systemdCgroupV2(l, false)
}
l.NewCgroupsManager = func(config *configs.Cgroup, paths map[string]string) cgroups.Manager {
return &systemd.LegacyManager{
Cgroups: config,
Paths: paths,
}
}
return nil
}
func cgroupfs2(l *LinuxFactory, rootless bool) error {
l.NewCgroupsManager = func(config *configs.Cgroup, paths map[string]string) cgroups.Manager {
m, err := fs2.NewManager(config, getUnifiedPath(paths), rootless)
if err != nil {
panic(err)
}
return m
}
return nil
}
// Cgroupfs is an options func to configure a LinuxFactory to return containers
// that use the native cgroups filesystem implementation to create and manage
// cgroups.
func Cgroupfs(l *LinuxFactory) error {
if cgroups.IsCgroup2UnifiedMode() {
return cgroupfs2(l, false)
}
l.NewCgroupsManager = func(config *configs.Cgroup, paths map[string]string) cgroups.Manager {
return &fs.Manager{
Cgroups: config,
Paths: paths,
}
}
return nil
}
// RootlessCgroupfs is an options func to configure a LinuxFactory to return
// containers that use the native cgroups filesystem implementation to create
// and manage cgroups. The difference between RootlessCgroupfs and Cgroupfs is
// that RootlessCgroupfs can transparently handle permission errors that occur
// during rootless container (including euid=0 in userns) setup (while still allowing cgroup usage if
// they've been set up properly).
func RootlessCgroupfs(l *LinuxFactory) error {
if cgroups.IsCgroup2UnifiedMode() {
return cgroupfs2(l, true)
}
l.NewCgroupsManager = func(config *configs.Cgroup, paths map[string]string) cgroups.Manager {
return &fs.Manager{
Cgroups: config,
Rootless: true,
Paths: paths,
}
}
return nil
}
// IntelRdtfs is an options func to configure a LinuxFactory to return
// containers that use the Intel RDT "resource control" filesystem to
// create and manage Intel RDT resources (e.g., L3 cache, memory bandwidth).
func IntelRdtFs(l *LinuxFactory) error {
l.NewIntelRdtManager = func(config *configs.Config, id string, path string) intelrdt.Manager {
return &intelrdt.IntelRdtManager{
Config: config,
Id: id,
Path: path,
}
}
return nil
}
// TmpfsRoot is an option func to mount LinuxFactory.Root to tmpfs.
func TmpfsRoot(l *LinuxFactory) error {
mounted, err := mountinfo.Mounted(l.Root)
if err != nil {
return err
}
if !mounted {
if err := unix.Mount("tmpfs", l.Root, "tmpfs", 0, ""); err != nil {
return err
}
}
return nil
}
// CriuPath returns an option func to configure a LinuxFactory with the
// provided criupath
func CriuPath(criupath string) func(*LinuxFactory) error {
return func(l *LinuxFactory) error {
l.CriuPath = criupath
return nil
}
}
// New returns a linux based container factory based in the root directory and
// configures the factory with the provided option funcs.
func New(root string, options ...func(*LinuxFactory) error) (Factory, error) {
if root != "" {
if err := os.MkdirAll(root, 0700); err != nil {
return nil, newGenericError(err, SystemError)
}
}
l := &LinuxFactory{
Root: root,
InitPath: "/proc/self/exe",
InitArgs: []string{os.Args[0], "init"},
Validator: validate.New(),
CriuPath: "criu",
}
Cgroupfs(l)
for _, opt := range options {
if opt == nil {
continue
}
if err := opt(l); err != nil {
return nil, err
}
}
return l, nil
}
// LinuxFactory implements the default factory interface for linux based systems.
type LinuxFactory struct {
// Root directory for the factory to store state.
Root string
// InitPath is the path for calling the init responsibilities for spawning
// a container.
InitPath string
// InitArgs are arguments for calling the init responsibilities for spawning
// a container.
InitArgs []string
// CriuPath is the path to the criu binary used for checkpoint and restore of
// containers.
CriuPath string
// New{u,g}uidmapPath is the path to the binaries used for mapping with
// rootless containers.
NewuidmapPath string
NewgidmapPath string
// Validator provides validation to container configurations.
Validator validate.Validator
// NewCgroupsManager returns an initialized cgroups manager for a single container.
NewCgroupsManager func(config *configs.Cgroup, paths map[string]string) cgroups.Manager
// NewIntelRdtManager returns an initialized Intel RDT manager for a single container.
NewIntelRdtManager func(config *configs.Config, id string, path string) intelrdt.Manager
}
func (l *LinuxFactory) Create(id string, config *configs.Config) (Container, error) {
if l.Root == "" {
return nil, newGenericError(fmt.Errorf("invalid root"), ConfigInvalid)
}
if err := l.validateID(id); err != nil {
return nil, err
}
if err := l.Validator.Validate(config); err != nil {
return nil, newGenericError(err, ConfigInvalid)
}
containerRoot, err := securejoin.SecureJoin(l.Root, id)
if err != nil {
return nil, err
}
if _, err := os.Stat(containerRoot); err == nil {
return nil, newGenericError(fmt.Errorf("container with id exists: %v", id), IdInUse)
} else if !os.IsNotExist(err) {
return nil, newGenericError(err, SystemError)
}
if err := os.MkdirAll(containerRoot, 0711); err != nil {
return nil, newGenericError(err, SystemError)
}
if err := os.Chown(containerRoot, unix.Geteuid(), unix.Getegid()); err != nil {
return nil, newGenericError(err, SystemError)
}
c := &linuxContainer{
id: id,
root: containerRoot,
config: config,
initPath: l.InitPath,
initArgs: l.InitArgs,
criuPath: l.CriuPath,
newuidmapPath: l.NewuidmapPath,
newgidmapPath: l.NewgidmapPath,
cgroupManager: l.NewCgroupsManager(config.Cgroups, nil),
}
if intelrdt.IsCatEnabled() || intelrdt.IsMbaEnabled() {
c.intelRdtManager = l.NewIntelRdtManager(config, id, "")
}
c.state = &stoppedState{c: c}
return c, nil
}
func (l *LinuxFactory) Load(id string) (Container, error) {
if l.Root == "" {
return nil, newGenericError(fmt.Errorf("invalid root"), ConfigInvalid)
}
//when load, we need to check id is valid or not.
if err := l.validateID(id); err != nil {
return nil, err
}
containerRoot, err := securejoin.SecureJoin(l.Root, id)
if err != nil {
return nil, err
}
state, err := l.loadState(containerRoot, id)
if err != nil {
return nil, err
}
r := &nonChildProcess{
processPid: state.InitProcessPid,
processStartTime: state.InitProcessStartTime,
fds: state.ExternalDescriptors,
}
c := &linuxContainer{
initProcess: r,
initProcessStartTime: state.InitProcessStartTime,
id: id,
config: &state.Config,
initPath: l.InitPath,
initArgs: l.InitArgs,
criuPath: l.CriuPath,
newuidmapPath: l.NewuidmapPath,
newgidmapPath: l.NewgidmapPath,
cgroupManager: l.NewCgroupsManager(state.Config.Cgroups, state.CgroupPaths),
root: containerRoot,
created: state.Created,
}
c.state = &loadedState{c: c}
if err := c.refreshState(); err != nil {
return nil, err
}
if intelrdt.IsCatEnabled() || intelrdt.IsMbaEnabled() {
c.intelRdtManager = l.NewIntelRdtManager(&state.Config, id, state.IntelRdtPath)
}
return c, nil
}
func (l *LinuxFactory) Type() string {
return "libcontainer"
}
// StartInitialization loads a container by opening the pipe fd from the parent to read the configuration and state
// This is a low level implementation detail of the reexec and should not be consumed externally
func (l *LinuxFactory) StartInitialization() (err error) {
var (
pipefd, fifofd int
consoleSocket *os.File
envInitPipe = os.Getenv("_LIBCONTAINER_INITPIPE")
envFifoFd = os.Getenv("_LIBCONTAINER_FIFOFD")
envConsole = os.Getenv("_LIBCONTAINER_CONSOLE")
)
// Get the INITPIPE.
pipefd, err = strconv.Atoi(envInitPipe)
if err != nil {
return fmt.Errorf("unable to convert _LIBCONTAINER_INITPIPE=%s to int: %s", envInitPipe, err)
}
var (
pipe = os.NewFile(uintptr(pipefd), "pipe")
it = initType(os.Getenv("_LIBCONTAINER_INITTYPE"))
)
defer pipe.Close()
// Only init processes have FIFOFD.
fifofd = -1
if it == initStandard {
if fifofd, err = strconv.Atoi(envFifoFd); err != nil {
return fmt.Errorf("unable to convert _LIBCONTAINER_FIFOFD=%s to int: %s", envFifoFd, err)
}
}
if envConsole != "" {
console, err := strconv.Atoi(envConsole)
if err != nil {
return fmt.Errorf("unable to convert _LIBCONTAINER_CONSOLE=%s to int: %s", envConsole, err)
}
consoleSocket = os.NewFile(uintptr(console), "console-socket")
defer consoleSocket.Close()
}
// clear the current process's environment to clean any libcontainer
// specific env vars.
os.Clearenv()
defer func() {
// We have an error during the initialization of the container's init,
// send it back to the parent process in the form of an initError.
if werr := utils.WriteJSON(pipe, syncT{procError}); werr != nil {
fmt.Fprintln(os.Stderr, err)
return
}
if werr := utils.WriteJSON(pipe, newSystemError(err)); werr != nil {
fmt.Fprintln(os.Stderr, err)
return
}
}()
defer func() {
if e := recover(); e != nil {
err = fmt.Errorf("panic from initialization: %v, %v", e, string(debug.Stack()))
}
}()
i, err := newContainerInit(it, pipe, consoleSocket, fifofd)
if err != nil {
return err
}
// If Init succeeds, syscall.Exec will not return, hence none of the defers will be called.
return i.Init()
}
func (l *LinuxFactory) loadState(root, id string) (*State, error) {
stateFilePath, err := securejoin.SecureJoin(root, stateFilename)
if err != nil {
return nil, err
}
f, err := os.Open(stateFilePath)
if err != nil {
if os.IsNotExist(err) {
return nil, newGenericError(fmt.Errorf("container %q does not exist", id), ContainerNotExists)
}
return nil, newGenericError(err, SystemError)
}
defer f.Close()
var state *State
if err := json.NewDecoder(f).Decode(&state); err != nil {
return nil, newGenericError(err, SystemError)
}
return state, nil
}
func (l *LinuxFactory) validateID(id string) error {
if !idRegex.MatchString(id) || string(os.PathSeparator)+id != utils.CleanPath(string(os.PathSeparator)+id) {
return newGenericError(fmt.Errorf("invalid id format: %v", id), InvalidIdFormat)
}
return nil
}
// NewuidmapPath returns an option func to configure a LinuxFactory with the
// provided ..
func NewuidmapPath(newuidmapPath string) func(*LinuxFactory) error {
return func(l *LinuxFactory) error {
l.NewuidmapPath = newuidmapPath
return nil
}
}
// NewgidmapPath returns an option func to configure a LinuxFactory with the
// provided ..
func NewgidmapPath(newgidmapPath string) func(*LinuxFactory) error {
return func(l *LinuxFactory) error {
l.NewgidmapPath = newgidmapPath
return nil
}
}