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135 lines
3.0 KiB
135 lines
3.0 KiB
package rootless
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import (
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"io/ioutil"
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"net"
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"os"
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"os/exec"
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"path/filepath"
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"strings"
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"github.com/pkg/errors"
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"github.com/rootless-containers/rootlesskit/pkg/child"
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"github.com/rootless-containers/rootlesskit/pkg/copyup/tmpfssymlink"
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"github.com/rootless-containers/rootlesskit/pkg/network/slirp4netns"
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"github.com/rootless-containers/rootlesskit/pkg/parent"
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portbuiltin "github.com/rootless-containers/rootlesskit/pkg/port/builtin"
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"github.com/sirupsen/logrus"
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)
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var (
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pipeFD = "_K3S_ROOTLESS_FD"
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childEnv = "_K3S_ROOTLESS_SOCK"
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Sock = ""
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)
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func Rootless(stateDir string) error {
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defer func() {
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os.Unsetenv(pipeFD)
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os.Unsetenv(childEnv)
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}()
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hasFD := os.Getenv(pipeFD) != ""
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hasChildEnv := os.Getenv(childEnv) != ""
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if hasFD {
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logrus.Debug("Running rootless child")
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childOpt, err := createChildOpt()
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if err != nil {
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logrus.Fatal(err)
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}
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if err := child.Child(*childOpt); err != nil {
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logrus.Fatal("child died", err)
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}
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}
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if hasChildEnv {
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Sock = os.Getenv(childEnv)
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logrus.Debug("Running rootless process")
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return setupMounts(stateDir)
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}
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logrus.Debug("Running rootless parent")
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parentOpt, err := createParentOpt(filepath.Join(stateDir, "rootless"))
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if err != nil {
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logrus.Fatal(err)
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}
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os.Setenv(childEnv, filepath.Join(parentOpt.StateDir, parent.StateFileAPISock))
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if err := parent.Parent(*parentOpt); err != nil {
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logrus.Fatal(err)
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}
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os.Exit(0)
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return nil
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}
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func parseCIDR(s string) (*net.IPNet, error) {
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if s == "" {
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return nil, nil
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}
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ip, ipnet, err := net.ParseCIDR(s)
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if err != nil {
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return nil, err
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}
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if !ip.Equal(ipnet.IP) {
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return nil, errors.Errorf("cidr must be like 10.0.2.0/24, not like 10.0.2.100/24")
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}
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return ipnet, nil
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}
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func createParentOpt(stateDir string) (*parent.Opt, error) {
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if err := os.MkdirAll(stateDir, 0755); err != nil {
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return nil, errors.Wrapf(err, "failed to mkdir %s", stateDir)
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}
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stateDir, err := ioutil.TempDir("", "rootless")
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if err != nil {
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return nil, err
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}
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opt := &parent.Opt{
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StateDir: stateDir,
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}
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mtu := 0
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ipnet, err := parseCIDR("10.41.0.0/16")
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if err != nil {
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return nil, err
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}
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disableHostLoopback := true
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binary := "slirp4netns"
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if _, err := exec.LookPath(binary); err != nil {
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return nil, err
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}
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opt.NetworkDriver = slirp4netns.NewParentDriver(binary, mtu, ipnet, disableHostLoopback, "")
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opt.PortDriver, err = portbuiltin.NewParentDriver(&logrusDebugWriter{}, stateDir)
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if err != nil {
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return nil, err
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}
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opt.PipeFDEnvKey = pipeFD
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return opt, nil
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}
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type logrusDebugWriter struct {
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}
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func (w *logrusDebugWriter) Write(p []byte) (int, error) {
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s := strings.TrimSuffix(string(p), "\n")
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logrus.Debug(s)
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return len(p), nil
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}
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func createChildOpt() (*child.Opt, error) {
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opt := &child.Opt{}
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opt.TargetCmd = os.Args
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opt.PipeFDEnvKey = pipeFD
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opt.NetworkDriver = slirp4netns.NewChildDriver()
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opt.PortDriver = portbuiltin.NewChildDriver(&logrusDebugWriter{})
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opt.CopyUpDirs = []string{"/etc", "/run", "/var/lib"}
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opt.CopyUpDriver = tmpfssymlink.NewChildDriver()
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return opt, nil
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}
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