/
spec_opts_unix.go
434 lines (407 loc) · 12.5 KB
/
spec_opts_unix.go
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// +build !windows
package containerd
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
"golang.org/x/sys/unix"
"github.com/containerd/containerd/containers"
"github.com/containerd/containerd/content"
"github.com/containerd/containerd/errdefs"
"github.com/containerd/containerd/fs"
"github.com/containerd/containerd/images"
"github.com/containerd/containerd/namespaces"
"github.com/containerd/containerd/platforms"
"github.com/opencontainers/image-spec/identity"
"github.com/opencontainers/image-spec/specs-go/v1"
"github.com/opencontainers/runc/libcontainer/user"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/pkg/errors"
)
// WithTTY sets the information on the spec as well as the environment variables for
// using a TTY
func WithTTY(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Process.Terminal = true
s.Process.Env = append(s.Process.Env, "TERM=xterm")
return nil
}
// WithHostNamespace allows a task to run inside the host's linux namespace
func WithHostNamespace(ns specs.LinuxNamespaceType) SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
for i, n := range s.Linux.Namespaces {
if n.Type == ns {
s.Linux.Namespaces = append(s.Linux.Namespaces[:i], s.Linux.Namespaces[i+1:]...)
return nil
}
}
return nil
}
}
// WithLinuxNamespace uses the passed in namespace for the spec. If a namespace of the same type already exists in the
// spec, the existing namespace is replaced by the one provided.
func WithLinuxNamespace(ns specs.LinuxNamespace) SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
for i, n := range s.Linux.Namespaces {
if n.Type == ns.Type {
before := s.Linux.Namespaces[:i]
after := s.Linux.Namespaces[i+1:]
s.Linux.Namespaces = append(before, ns)
s.Linux.Namespaces = append(s.Linux.Namespaces, after...)
return nil
}
}
s.Linux.Namespaces = append(s.Linux.Namespaces, ns)
return nil
}
}
// WithImageConfig configures the spec to from the configuration of an Image
func WithImageConfig(i Image) SpecOpts {
return func(ctx context.Context, client *Client, c *containers.Container, s *specs.Spec) error {
var (
image = i.(*image)
store = client.ContentStore()
)
ic, err := image.i.Config(ctx, store, platforms.Default())
if err != nil {
return err
}
var (
ociimage v1.Image
config v1.ImageConfig
)
switch ic.MediaType {
case v1.MediaTypeImageConfig, images.MediaTypeDockerSchema2Config:
p, err := content.ReadBlob(ctx, store, ic.Digest)
if err != nil {
return err
}
if err := json.Unmarshal(p, &ociimage); err != nil {
return err
}
config = ociimage.Config
default:
return fmt.Errorf("unknown image config media type %s", ic.MediaType)
}
s.Process.Env = append(s.Process.Env, config.Env...)
cmd := config.Cmd
s.Process.Args = append(config.Entrypoint, cmd...)
if config.User != "" {
parts := strings.Split(config.User, ":")
switch len(parts) {
case 1:
v, err := strconv.ParseUint(parts[0], 0, 10)
if err != nil {
// if we cannot parse as a uint they try to see if it is a username
if err := WithUsername(config.User)(ctx, client, c, s); err != nil {
return err
}
return err
}
if err := WithUserID(uint32(v))(ctx, client, c, s); err != nil {
return err
}
case 2:
v, err := strconv.ParseUint(parts[0], 0, 10)
if err != nil {
return err
}
uid := uint32(v)
if v, err = strconv.ParseUint(parts[1], 0, 10); err != nil {
return err
}
gid := uint32(v)
s.Process.User.UID, s.Process.User.GID = uid, gid
default:
return fmt.Errorf("invalid USER value %s", config.User)
}
}
cwd := config.WorkingDir
if cwd == "" {
cwd = "/"
}
s.Process.Cwd = cwd
return nil
}
}
// WithRootFSPath specifies unmanaged rootfs path.
func WithRootFSPath(path string) SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
if s.Root == nil {
s.Root = &specs.Root{}
}
s.Root.Path = path
// Entrypoint is not set here (it's up to caller)
return nil
}
}
// WithRootFSReadonly sets specs.Root.Readonly to true
func WithRootFSReadonly() SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
if s.Root == nil {
s.Root = &specs.Root{}
}
s.Root.Readonly = true
return nil
}
}
// WithResources sets the provided resources on the spec for task updates
func WithResources(resources *specs.LinuxResources) UpdateTaskOpts {
return func(ctx context.Context, client *Client, r *UpdateTaskInfo) error {
r.Resources = resources
return nil
}
}
// WithNoNewPrivileges sets no_new_privileges on the process for the container
func WithNoNewPrivileges(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Process.NoNewPrivileges = true
return nil
}
// WithHostHostsFile bind-mounts the host's /etc/hosts into the container as readonly
func WithHostHostsFile(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Mounts = append(s.Mounts, specs.Mount{
Destination: "/etc/hosts",
Type: "bind",
Source: "/etc/hosts",
Options: []string{"rbind", "ro"},
})
return nil
}
// WithHostResolvconf bind-mounts the host's /etc/resolv.conf into the container as readonly
func WithHostResolvconf(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Mounts = append(s.Mounts, specs.Mount{
Destination: "/etc/resolv.conf",
Type: "bind",
Source: "/etc/resolv.conf",
Options: []string{"rbind", "ro"},
})
return nil
}
// WithHostLocaltime bind-mounts the host's /etc/localtime into the container as readonly
func WithHostLocaltime(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Mounts = append(s.Mounts, specs.Mount{
Destination: "/etc/localtime",
Type: "bind",
Source: "/etc/localtime",
Options: []string{"rbind", "ro"},
})
return nil
}
// WithUserNamespace sets the uid and gid mappings for the task
// this can be called multiple times to add more mappings to the generated spec
func WithUserNamespace(container, host, size uint32) SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
var hasUserns bool
for _, ns := range s.Linux.Namespaces {
if ns.Type == specs.UserNamespace {
hasUserns = true
break
}
}
if !hasUserns {
s.Linux.Namespaces = append(s.Linux.Namespaces, specs.LinuxNamespace{
Type: specs.UserNamespace,
})
}
mapping := specs.LinuxIDMapping{
ContainerID: container,
HostID: host,
Size: size,
}
s.Linux.UIDMappings = append(s.Linux.UIDMappings, mapping)
s.Linux.GIDMappings = append(s.Linux.GIDMappings, mapping)
return nil
}
}
// WithRemappedSnapshot creates a new snapshot and remaps the uid/gid for the
// filesystem to be used by a container with user namespaces
func WithRemappedSnapshot(id string, i Image, uid, gid uint32) NewContainerOpts {
return withRemappedSnapshotBase(id, i, uid, gid, false)
}
// WithRemappedSnapshotView is similar to WithRemappedSnapshot but rootfs is mounted as read-only.
func WithRemappedSnapshotView(id string, i Image, uid, gid uint32) NewContainerOpts {
return withRemappedSnapshotBase(id, i, uid, gid, true)
}
func withRemappedSnapshotBase(id string, i Image, uid, gid uint32, readonly bool) NewContainerOpts {
return func(ctx context.Context, client *Client, c *containers.Container) error {
diffIDs, err := i.(*image).i.RootFS(ctx, client.ContentStore(), platforms.Default())
if err != nil {
return err
}
setSnapshotterIfEmpty(c)
var (
snapshotter = client.SnapshotService(c.Snapshotter)
parent = identity.ChainID(diffIDs).String()
usernsID = fmt.Sprintf("%s-%d-%d", parent, uid, gid)
)
if _, err := snapshotter.Stat(ctx, usernsID); err == nil {
if _, err := snapshotter.Prepare(ctx, id, usernsID); err == nil {
c.SnapshotKey = id
c.Image = i.Name()
return nil
} else if !errdefs.IsNotFound(err) {
return err
}
}
mounts, err := snapshotter.Prepare(ctx, usernsID+"-remap", parent)
if err != nil {
return err
}
if err := remapRootFS(mounts, uid, gid); err != nil {
snapshotter.Remove(ctx, usernsID)
return err
}
if err := snapshotter.Commit(ctx, usernsID, usernsID+"-remap"); err != nil {
return err
}
if readonly {
_, err = snapshotter.View(ctx, id, usernsID)
} else {
_, err = snapshotter.Prepare(ctx, id, usernsID)
}
if err != nil {
return err
}
c.SnapshotKey = id
c.Image = i.Name()
return nil
}
}
// WithCgroup sets the container's cgroup path
func WithCgroup(path string) SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Linux.CgroupsPath = path
return nil
}
}
// WithNamespacedCgroup uses the namespace set on the context to create a
// root directory for containers in the cgroup with the id as the subcgroup
func WithNamespacedCgroup() SpecOpts {
return func(ctx context.Context, _ *Client, c *containers.Container, s *specs.Spec) error {
namespace, err := namespaces.NamespaceRequired(ctx)
if err != nil {
return err
}
s.Linux.CgroupsPath = filepath.Join("/", namespace, c.ID)
return nil
}
}
// WithUIDGID allows the UID and GID for the Process to be set
func WithUIDGID(uid, gid uint32) SpecOpts {
return func(_ context.Context, _ *Client, _ *containers.Container, s *specs.Spec) error {
s.Process.User.UID = uid
s.Process.User.GID = gid
return nil
}
}
// WithUserID sets the correct UID and GID for the container based
// on the image's /etc/passwd contents. If /etc/passwd does not exist,
// or uid is not found in /etc/passwd, it sets gid to be the same with
// uid, and not returns error.
func WithUserID(uid uint32) SpecOpts {
return func(ctx context.Context, client *Client, c *containers.Container, s *specs.Spec) error {
if c.Snapshotter == "" {
return errors.Errorf("no snapshotter set for container")
}
if c.SnapshotKey == "" {
return errors.Errorf("rootfs snapshot not created for container")
}
snapshotter := client.SnapshotService(c.Snapshotter)
mounts, err := snapshotter.Mounts(ctx, c.SnapshotKey)
if err != nil {
return err
}
root, err := ioutil.TempDir("", "ctd-username")
if err != nil {
return err
}
defer os.RemoveAll(root)
for _, m := range mounts {
if err := m.Mount(root); err != nil {
return err
}
}
defer unix.Unmount(root, 0)
ppath, err := fs.RootPath(root, "/etc/passwd")
if err != nil {
return err
}
f, err := os.Open(ppath)
if err != nil {
if os.IsNotExist(err) {
s.Process.User.UID, s.Process.User.GID = uid, uid
return nil
}
return err
}
defer f.Close()
users, err := user.ParsePasswdFilter(f, func(u user.User) bool {
return u.Uid == int(uid)
})
if err != nil {
return err
}
if len(users) == 0 {
s.Process.User.UID, s.Process.User.GID = uid, uid
return nil
}
u := users[0]
s.Process.User.UID, s.Process.User.GID = uint32(u.Uid), uint32(u.Gid)
return nil
}
}
// WithUsername sets the correct UID and GID for the container
// based on the the image's /etc/passwd contents. If /etc/passwd
// does not exist, or the username is not found in /etc/passwd,
// it returns error.
func WithUsername(username string) SpecOpts {
return func(ctx context.Context, client *Client, c *containers.Container, s *specs.Spec) error {
if c.Snapshotter == "" {
return errors.Errorf("no snapshotter set for container")
}
if c.SnapshotKey == "" {
return errors.Errorf("rootfs snapshot not created for container")
}
snapshotter := client.SnapshotService(c.Snapshotter)
mounts, err := snapshotter.Mounts(ctx, c.SnapshotKey)
if err != nil {
return err
}
root, err := ioutil.TempDir("", "ctd-username")
if err != nil {
return err
}
defer os.RemoveAll(root)
for _, m := range mounts {
if err := m.Mount(root); err != nil {
return err
}
}
defer unix.Unmount(root, 0)
ppath, err := fs.RootPath(root, "/etc/passwd")
if err != nil {
return err
}
f, err := os.Open(ppath)
if err != nil {
return err
}
defer f.Close()
users, err := user.ParsePasswdFilter(f, func(u user.User) bool {
return u.Name == username
})
if err != nil {
return err
}
if len(users) == 0 {
return errors.Errorf("no users found for %s", username)
}
u := users[0]
s.Process.User.UID, s.Process.User.GID = uint32(u.Uid), uint32(u.Gid)
return nil
}
}