rootlessport: reduce memory usage of the process

Don't use reexec for the rootlessport process, instead make it a
separate binary to reduce the memory usage. The problem with reexec is
that it will import all packages that podman uses and therefore loads a
lot of stuff into the heap. The rootlessport process however only needs
the rootlesskit library.
The memory usage is a concern since the rootlessport process will spawn
two process per container which has ports forwarded. The processes stay
until the container dies. On my laptop the current reexec version uses
47800 KB RSS. The new separate binary only uses 4540 KB RSS. This is
more than a 90% improvement.

The Makefile has been updated to compile the new binary and install it
to the libexec directory.

Fixes #10790

[NO TESTS NEEDED]

Signed-off-by: Paul Holzinger <pholzing@redhat.com>

Makefile

@@ -39,6 +39,7 @@ LIBPOD_INSTANCE := libpod_dev
 PREFIX ?= /usr/local
 BINDIR ?= ${PREFIX}/bin
 LIBEXECDIR ?= ${PREFIX}/libexec
+LIBEXECPODMAN ?= ${LIBEXECDIR}/podman
 MANDIR ?= ${PREFIX}/share/man
 SHAREDIR_CONTAINERS ?= ${PREFIX}/share/containers
 ETCDIR ?= ${PREFIX}/etc
@@ -186,7 +187,7 @@ default: all
 all: binaries docs
 
 .PHONY: binaries
-binaries: podman podman-remote ## Build podman and podman-remote binaries
+binaries: podman podman-remote rootlessport ## Build podman, podman-remote and rootlessport binaries
 
 # Extract text following double-# for targets, as their description for
 # the `help` target.  Otherwise These simple-substitutions are resolved
@@ -355,6 +356,15 @@ podman-remote-darwin: ## Build podman-remote for macOS
 		GOARCH=$(GOARCH) \
 		bin/darwin/podman
 
+bin/rootlessport: .gopathok $(SOURCES) go.mod go.sum
+	CGO_ENABLED=$(CGO_ENABLED) \
+		$(GO) build \
+		$(BUILDFLAGS) \
+		-o $@ ./cmd/rootlessport
+
+.PHONY: rootlessport
+rootlessport: bin/rootlessport
+
 ###
 ### Secondary binary-build targets
 ###
@@ -718,11 +728,14 @@ install.bin-nobuild:
 	install ${SELINUXOPT} -d -m 755 $(DESTDIR)$(BINDIR)
 	install ${SELINUXOPT} -m 755 bin/podman $(DESTDIR)$(BINDIR)/podman
 	test -z "${SELINUXOPT}" || chcon --verbose --reference=$(DESTDIR)$(BINDIR)/podman bin/podman
+	install ${SELINUXOPT} -d -m 755 $(DESTDIR)$(LIBEXECPODMAN)
+	install ${SELINUXOPT} -m 755 bin/rootlessport $(DESTDIR)$(LIBEXECPODMAN)/rootlessport
+	test -z "${SELINUXOPT}" || chcon --verbose --reference=$(DESTDIR)$(LIBEXECPODMAN)/rootlessport bin/rootlessport
 	install ${SELINUXOPT} -m 755 -d ${DESTDIR}${TMPFILESDIR}
 	install ${SELINUXOPT} -m 644 contrib/tmpfile/podman.conf ${DESTDIR}${TMPFILESDIR}/podman.conf
 
 .PHONY: install.bin
-install.bin: podman install.bin-nobuild
+install.bin: podman rootlessport install.bin-nobuild
 
 .PHONY: install.man-nobuild
 install.man-nobuild:

cmd/rootlessport/main.go

@@ -0,0 +1,353 @@
+package main
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"os"
+	"os/exec"
+	"path/filepath"
+
+	"github.com/containernetworking/plugins/pkg/ns"
+	"github.com/containers/podman/v3/libpod/network/types"
+	"github.com/containers/podman/v3/pkg/rootlessport"
+	"github.com/pkg/errors"
+	rkport "github.com/rootless-containers/rootlesskit/pkg/port"
+	rkbuiltin "github.com/rootless-containers/rootlesskit/pkg/port/builtin"
+	rkportutil "github.com/rootless-containers/rootlesskit/pkg/port/portutil"
+	"github.com/sirupsen/logrus"
+	"golang.org/x/sys/unix"
+)
+
+const (
+	// ReexecChildKey is used internally for the second reexec
+	ReexecChildKey       = "rootlessport-child"
+	reexecChildEnvOpaque = "_CONTAINERS_ROOTLESSPORT_CHILD_OPAQUE"
+)
+
+func main() {
+	if len(os.Args) > 1 {
+		fmt.Fprintln(os.Stderr, `too many arguments, rootlessport expects a json config via STDIN`)
+		os.Exit(1)
+	}
+	var err error
+	if os.Args[0] == ReexecChildKey {
+		err = child()
+	} else {
+		err = parent()
+	}
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+}
+
+func loadConfig(r io.Reader) (*rootlessport.Config, io.ReadCloser, io.WriteCloser, error) {
+	stdin, err := ioutil.ReadAll(r)
+	if err != nil {
+		return nil, nil, nil, err
+	}
+	var cfg rootlessport.Config
+	if err := json.Unmarshal(stdin, &cfg); err != nil {
+		return nil, nil, nil, err
+	}
+	if cfg.NetNSPath == "" {
+		return nil, nil, nil, errors.New("missing NetNSPath")
+	}
+	if cfg.ExitFD <= 0 {
+		return nil, nil, nil, errors.New("missing ExitFD")
+	}
+	exitFile := os.NewFile(uintptr(cfg.ExitFD), "exitfile")
+	if exitFile == nil {
+		return nil, nil, nil, errors.New("invalid ExitFD")
+	}
+	if cfg.ReadyFD <= 0 {
+		return nil, nil, nil, errors.New("missing ReadyFD")
+	}
+	readyFile := os.NewFile(uintptr(cfg.ReadyFD), "readyfile")
+	if readyFile == nil {
+		return nil, nil, nil, errors.New("invalid ReadyFD")
+	}
+	return &cfg, exitFile, readyFile, nil
+}
+
+func parent() error {
+	// load config from stdin
+	cfg, exitR, readyW, err := loadConfig(os.Stdin)
+	if err != nil {
+		return err
+	}
+
+	socketDir := filepath.Join(cfg.TmpDir, "rp")
+	err = os.MkdirAll(socketDir, 0700)
+	if err != nil {
+		return err
+	}
+
+	// create the parent driver
+	stateDir, err := ioutil.TempDir(cfg.TmpDir, "rootlessport")
+	if err != nil {
+		return err
+	}
+	defer os.RemoveAll(stateDir)
+	driver, err := rkbuiltin.NewParentDriver(&logrusWriter{prefix: "parent: "}, stateDir)
+	if err != nil {
+		return err
+	}
+	initComplete := make(chan struct{})
+	quit := make(chan struct{})
+	errCh := make(chan error)
+	// start the parent driver. initComplete will be closed when the child connected to the parent.
+	logrus.Infof("Starting parent driver")
+	go func() {
+		driverErr := driver.RunParentDriver(initComplete, quit, nil)
+		if driverErr != nil {
+			logrus.WithError(driverErr).Warn("Parent driver exited")
+		}
+		errCh <- driverErr
+		close(errCh)
+	}()
+	opaque := driver.OpaqueForChild()
+	logrus.Infof("opaque=%+v", opaque)
+	opaqueJSON, err := json.Marshal(opaque)
+	if err != nil {
+		return err
+	}
+	childQuitR, childQuitW, err := os.Pipe()
+	if err != nil {
+		return err
+	}
+	defer func() {
+		// stop the child
+		logrus.Info("Stopping child driver")
+		if err := childQuitW.Close(); err != nil {
+			logrus.WithError(err).Warn("Unable to close childQuitW")
+		}
+	}()
+
+	// reexec the child process in the child netns
+	cmd := exec.Command("/proc/self/exe")
+	cmd.Args = []string{ReexecChildKey}
+	cmd.Stdin = childQuitR
+	cmd.Stdout = &logrusWriter{prefix: "child"}
+	cmd.Stderr = cmd.Stdout
+	cmd.Env = append(os.Environ(), reexecChildEnvOpaque+"="+string(opaqueJSON))
+	childNS, err := ns.GetNS(cfg.NetNSPath)
+	if err != nil {
+		return err
+	}
+	if err := childNS.Do(func(_ ns.NetNS) error {
+		logrus.Infof("Starting child driver in child netns (%q %v)", cmd.Path, cmd.Args)
+		return cmd.Start()
+	}); err != nil {
+		return err
+	}
+
+	childErrCh := make(chan error)
+	go func() {
+		err := cmd.Wait()
+		childErrCh <- err
+		close(childErrCh)
+	}()
+
+	defer func() {
+		if err := unix.Kill(cmd.Process.Pid, unix.SIGTERM); err != nil {
+			logrus.WithError(err).Warn("Kill child process")
+		}
+	}()
+
+	logrus.Info("Waiting for initComplete")
+	// wait for the child to connect to the parent
+outer:
+	for {
+		select {
+		case <-initComplete:
+			logrus.Infof("initComplete is closed; parent and child established the communication channel")
+			break outer
+		case err := <-childErrCh:
+			if err != nil {
+				return err
+			}
+		case err := <-errCh:
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	defer func() {
+		logrus.Info("Stopping parent driver")
+		quit <- struct{}{}
+		if err := <-errCh; err != nil {
+			logrus.WithError(err).Warn("Parent driver returned error on exit")
+		}
+	}()
+
+	// let parent expose ports
+	logrus.Infof("Exposing ports %v", cfg.Mappings)
+	if err := exposePorts(driver, cfg.Mappings, cfg.ChildIP); err != nil {
+		return err
+	}
+
+	// we only need to have a socket to reload ports when we run under rootless cni
+	if cfg.RootlessCNI {
+		socketfile := filepath.Join(socketDir, cfg.ContainerID)
+		// make sure to remove the file if it exists to prevent EADDRINUSE
+		_ = os.Remove(socketfile)
+		// workaround to bypass the 108 char socket path limit
+		// open the fd and use the path to the fd as bind argument
+		fd, err := unix.Open(socketDir, unix.O_PATH, 0)
+		if err != nil {
+			return err
+		}
+		socket, err := net.ListenUnix("unixpacket", &net.UnixAddr{Name: fmt.Sprintf("/proc/self/fd/%d/%s", fd, cfg.ContainerID), Net: "unixpacket"})
+		if err != nil {
+			return err
+		}
+		err = unix.Close(fd)
+		// remove the socket file on exit
+		defer os.Remove(socketfile)
+		if err != nil {
+			logrus.Warnf("Failed to close the socketDir fd: %v", err)
+		}
+		defer socket.Close()
+		go serve(socket, driver)
+	}
+
+	logrus.Info("Ready")
+
+	// https://github.com/containers/podman/issues/11248
+	// Copy /dev/null to stdout and stderr to prevent SIGPIPE errors
+	if f, err := os.OpenFile("/dev/null", os.O_WRONLY, 0755); err == nil {
+		unix.Dup2(int(f.Fd()), 1) // nolint:errcheck
+		unix.Dup2(int(f.Fd()), 2) // nolint:errcheck
+		f.Close()
+	}
+	// write and close ReadyFD (convention is same as slirp4netns --ready-fd)
+	if _, err := readyW.Write([]byte("1")); err != nil {
+		return err
+	}
+	if err := readyW.Close(); err != nil {
+		return err
+	}
+
+	// wait for ExitFD to be closed
+	logrus.Info("Waiting for exitfd to be closed")
+	if _, err := ioutil.ReadAll(exitR); err != nil {
+		return err
+	}
+	return nil
+}
+
+func serve(listener net.Listener, pm rkport.Manager) {
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			// we cannot log this error, stderr is already closed
+			continue
+		}
+		ctx := context.TODO()
+		err = handler(ctx, conn, pm)
+		if err != nil {
+			conn.Write([]byte(err.Error()))
+		} else {
+			conn.Write([]byte("OK"))
+		}
+		conn.Close()
+	}
+}
+
+func handler(ctx context.Context, conn io.Reader, pm rkport.Manager) error {
+	var childIP string
+	dec := json.NewDecoder(conn)
+	err := dec.Decode(&childIP)
+	if err != nil {
+		return errors.Wrap(err, "rootless port failed to decode ports")
+	}
+	portStatus, err := pm.ListPorts(ctx)
+	if err != nil {
+		return errors.Wrap(err, "rootless port failed to list ports")
+	}
+	for _, status := range portStatus {
+		err = pm.RemovePort(ctx, status.ID)
+		if err != nil {
+			return errors.Wrap(err, "rootless port failed to remove port")
+		}
+	}
+	// add the ports with the new child IP
+	for _, status := range portStatus {
+		// set the new child IP
+		status.Spec.ChildIP = childIP
+		_, err = pm.AddPort(ctx, status.Spec)
+		if err != nil {
+			return errors.Wrap(err, "rootless port failed to add port")
+		}
+	}
+	return nil
+}
+
+func exposePorts(pm rkport.Manager, portMappings []types.OCICNIPortMapping, childIP string) error {
+	ctx := context.TODO()
+	for _, i := range portMappings {
+		hostIP := i.HostIP
+		if hostIP == "" {
+			hostIP = "0.0.0.0"
+		}
+		spec := rkport.Spec{
+			Proto:      i.Protocol,
+			ParentIP:   hostIP,
+			ParentPort: int(i.HostPort),
+			ChildPort:  int(i.ContainerPort),
+			ChildIP:    childIP,
+		}
+		if err := rkportutil.ValidatePortSpec(spec, nil); err != nil {
+			return err
+		}
+		if _, err := pm.AddPort(ctx, spec); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func child() error {
+	// load the config from the parent
+	var opaque map[string]string
+	if err := json.Unmarshal([]byte(os.Getenv(reexecChildEnvOpaque)), &opaque); err != nil {
+		return err
+	}
+
+	// start the child driver
+	quit := make(chan struct{})
+	errCh := make(chan error)
+	go func() {
+		d := rkbuiltin.NewChildDriver(os.Stderr)
+		dErr := d.RunChildDriver(opaque, quit)
+		errCh <- dErr
+	}()
+	defer func() {
+		logrus.Info("Stopping child driver")
+		quit <- struct{}{}
+		if err := <-errCh; err != nil {
+			logrus.WithError(err).Warn("Child driver returned error on exit")
+		}
+	}()
+
+	// wait for stdin to be closed
+	if _, err := ioutil.ReadAll(os.Stdin); err != nil {
+		return err
+	}
+	return nil
+}
+
+type logrusWriter struct {
+	prefix string
+}
+
+func (w *logrusWriter) Write(p []byte) (int, error) {
+	logrus.Infof("%s%s", w.prefix, string(p))
+	return len(p), nil
+}

contrib/cirrus/setup_environment.sh

@@ -236,9 +236,19 @@ case "$TEST_FLAVOR" in
         # Use existing host bits when testing is to happen inside a container
         # since this script will run again in that environment.
         # shellcheck disable=SC2154
-        if ((CONTAINER==0)) && [[ "$TEST_ENVIRON" == "host" ]]; then
+        if [[ "$TEST_ENVIRON" == "host" ]]; then
+            if ((CONTAINER)); then
+                die "Refusing to config. host-test in container";
+            fi
             remove_packaged_podman_files
             make install PREFIX=/usr ETCDIR=/etc
+        elif [[ "$TEST_ENVIRON" == "container" ]]; then
+            if ((CONTAINER)); then
+                remove_packaged_podman_files
+                make install PREFIX=/usr ETCDIR=/etc
+            fi
+        else
+            die "Invalid value for $$TEST_ENVIRON=$TEST_ENVIRON"
         fi
 
         install_test_configs

contrib/spec/podman.spec.in

@@ -3,18 +3,8 @@
 %global with_check 0
 %global with_unit_test 0
 %bcond_without doc
-%bcond_without debug
 
-%if %{with debug}
-%global _find_debuginfo_dwz_opts %{nil}
-%global _dwz_low_mem_die_limit 0
-%else
 %global debug_package   %{nil}
-%endif
-
-%if ! 0%{?gobuild:1}
-%define gobuild(o:) go build -buildmode pie -compiler gc -tags="rpm_crashtraceback ${BUILDTAGS:-}" -ldflags "${LDFLAGS:-} -B 0x$(head -c20 /dev/urandom|od -An -tx1|tr -d ' \n') -extldflags '-Wl,-z,relro -Wl,--as-needed  -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld  '" -a -v -x %{?**};
-%endif
 
 # podman hack directory
 %define hackdir %{_builddir}/%{repo}-%{shortcommit0}
@@ -536,6 +526,8 @@ export GOPATH=%{buildroot}/%{gopath}:$(pwd)/vendor:%{gopath}
 %{_usr}/lib/systemd/user/podman-auto-update.timer
 %{_usr}/lib/systemd/user/podman-restart.service
 %{_usr}/lib/tmpfiles.d/podman.conf
+%dir %{_libexecdir}/%{name}
+%{_libexecdir}/%{name}/rootlessport
 
 %if 0%{?with_devel}
 %files -n libpod-devel -f devel.file-list

libpod/networking_slirp4netns.go

@@ -484,10 +484,14 @@ func (r *Runtime) setupRootlessPortMappingViaRLK(ctr *Container, netnsPath strin
 	}
 	cfgR := bytes.NewReader(cfgJSON)
 	var stdout bytes.Buffer
-	cmd := exec.Command(fmt.Sprintf("/proc/%d/exe", os.Getpid()))
+	path, err := r.config.FindHelperBinary(rootlessport.BinaryName, false)
-	cmd.Args = []string{rootlessport.ReexecKey}
+	if err != nil {
-	// Leak one end of the pipe in rootlessport process, the other will be sent to conmon
+		return err
+	}
+	cmd := exec.Command(path)
+	cmd.Args = []string{rootlessport.BinaryName}
 
+	// Leak one end of the pipe in rootlessport process, the other will be sent to conmon
 	if ctr.rootlessPortSyncR != nil {
 		defer errorhandling.CloseQuiet(ctr.rootlessPortSyncR)
 	}

nix/default-arm64.nix

@@ -77,10 +77,12 @@ let
       patchShebangs .
       make bin/podman
       make bin/podman-remote
+      make bin/rootlessport
     '';
     installPhase = ''
       install -Dm755 bin/podman $out/bin/podman
       install -Dm755 bin/podman-remote $out/bin/podman-remote
+      install -Dm755 bin/rootlessport $out/libexec/podman/rootlessport
     '';
   };
 in

nix/default.nix

@@ -75,10 +75,12 @@ let
       patchShebangs .
       make bin/podman
       make bin/podman-remote
+      make bin/rootlessport
     '';
     installPhase = ''
       install -Dm755 bin/podman $out/bin/podman
       install -Dm755 bin/podman-remote $out/bin/podman-remote
+      install -Dm755 bin/rootlessport $out/libexec/podman/rootlessport
     '';
   };
 in

pkg/rootlessport/rootlessport_linux.go

@@ -12,33 +12,12 @@
 package rootlessport
 
 import (
-	"context"
-	"encoding/json"
-	"fmt"
-	"io"
-	"io/ioutil"
-	"net"
-	"os"
-	"os/exec"
-	"path/filepath"
-
-	"github.com/containernetworking/plugins/pkg/ns"
 	"github.com/containers/podman/v3/libpod/network/types"
-	"github.com/containers/storage/pkg/reexec"
-	"github.com/pkg/errors"
-	rkport "github.com/rootless-containers/rootlesskit/pkg/port"
-	rkbuiltin "github.com/rootless-containers/rootlesskit/pkg/port/builtin"
-	rkportutil "github.com/rootless-containers/rootlesskit/pkg/port/portutil"
-	"github.com/sirupsen/logrus"
-	"golang.org/x/sys/unix"
 )
 
 const (
-	// ReexecKey is the reexec key for the parent process.
+	// BinaryName is the binary name for the parent process.
-	ReexecKey = "containers-rootlessport"
+	BinaryName = "rootlessport"
-	// reexecChildKey is used internally for the second reexec
-	reexecChildKey       = "containers-rootlessport-child"
-	reexecChildEnvOpaque = "_CONTAINERS_ROOTLESSPORT_CHILD_OPAQUE"
 )
 
 // Config needs to be provided to the process via stdin as a JSON string.
@@ -53,325 +32,3 @@ type Config struct {
 	ContainerID string
 	RootlessCNI bool
 }
-
-func init() {
-	reexec.Register(ReexecKey, func() {
-		if err := parent(); err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-	})
-	reexec.Register(reexecChildKey, func() {
-		if err := child(); err != nil {
-			fmt.Println(err)
-			os.Exit(1)
-		}
-	})
-}
-
-func loadConfig(r io.Reader) (*Config, io.ReadCloser, io.WriteCloser, error) {
-	stdin, err := ioutil.ReadAll(r)
-	if err != nil {
-		return nil, nil, nil, err
-	}
-	var cfg Config
-	if err := json.Unmarshal(stdin, &cfg); err != nil {
-		return nil, nil, nil, err
-	}
-	if cfg.NetNSPath == "" {
-		return nil, nil, nil, errors.New("missing NetNSPath")
-	}
-	if cfg.ExitFD <= 0 {
-		return nil, nil, nil, errors.New("missing ExitFD")
-	}
-	exitFile := os.NewFile(uintptr(cfg.ExitFD), "exitfile")
-	if exitFile == nil {
-		return nil, nil, nil, errors.New("invalid ExitFD")
-	}
-	if cfg.ReadyFD <= 0 {
-		return nil, nil, nil, errors.New("missing ReadyFD")
-	}
-	readyFile := os.NewFile(uintptr(cfg.ReadyFD), "readyfile")
-	if readyFile == nil {
-		return nil, nil, nil, errors.New("invalid ReadyFD")
-	}
-	return &cfg, exitFile, readyFile, nil
-}
-
-func parent() error {
-	// load config from stdin
-	cfg, exitR, readyW, err := loadConfig(os.Stdin)
-	if err != nil {
-		return err
-	}
-
-	socketDir := filepath.Join(cfg.TmpDir, "rp")
-	err = os.MkdirAll(socketDir, 0700)
-	if err != nil {
-		return err
-	}
-
-	// create the parent driver
-	stateDir, err := ioutil.TempDir(cfg.TmpDir, "rootlessport")
-	if err != nil {
-		return err
-	}
-	defer os.RemoveAll(stateDir)
-	driver, err := rkbuiltin.NewParentDriver(&logrusWriter{prefix: "parent: "}, stateDir)
-	if err != nil {
-		return err
-	}
-	initComplete := make(chan struct{})
-	quit := make(chan struct{})
-	errCh := make(chan error)
-	// start the parent driver. initComplete will be closed when the child connected to the parent.
-	logrus.Infof("Starting parent driver")
-	go func() {
-		driverErr := driver.RunParentDriver(initComplete, quit, nil)
-		if driverErr != nil {
-			logrus.WithError(driverErr).Warn("Parent driver exited")
-		}
-		errCh <- driverErr
-		close(errCh)
-	}()
-	opaque := driver.OpaqueForChild()
-	logrus.Infof("Opaque=%+v", opaque)
-	opaqueJSON, err := json.Marshal(opaque)
-	if err != nil {
-		return err
-	}
-	childQuitR, childQuitW, err := os.Pipe()
-	if err != nil {
-		return err
-	}
-	defer func() {
-		// stop the child
-		logrus.Info("Stopping child driver")
-		if err := childQuitW.Close(); err != nil {
-			logrus.WithError(err).Warn("Unable to close childQuitW")
-		}
-	}()
-
-	// reexec the child process in the child netns
-	cmd := exec.Command("/proc/self/exe")
-	cmd.Args = []string{reexecChildKey}
-	cmd.Stdin = childQuitR
-	cmd.Stdout = &logrusWriter{prefix: "child"}
-	cmd.Stderr = cmd.Stdout
-	cmd.Env = append(os.Environ(), reexecChildEnvOpaque+"="+string(opaqueJSON))
-	childNS, err := ns.GetNS(cfg.NetNSPath)
-	if err != nil {
-		return err
-	}
-	if err := childNS.Do(func(_ ns.NetNS) error {
-		logrus.Infof("Starting child driver in child netns (%q %v)", cmd.Path, cmd.Args)
-		return cmd.Start()
-	}); err != nil {
-		return err
-	}
-
-	childErrCh := make(chan error)
-	go func() {
-		err := cmd.Wait()
-		childErrCh <- err
-		close(childErrCh)
-	}()
-
-	defer func() {
-		if err := unix.Kill(cmd.Process.Pid, unix.SIGTERM); err != nil {
-			logrus.WithError(err).Warn("Kill child process")
-		}
-	}()
-
-	logrus.Info("Waiting for initComplete")
-	// wait for the child to connect to the parent
-outer:
-	for {
-		select {
-		case <-initComplete:
-			logrus.Infof("initComplete is closed; parent and child established the communication channel")
-			break outer
-		case err := <-childErrCh:
-			if err != nil {
-				return err
-			}
-		case err := <-errCh:
-			if err != nil {
-				return err
-			}
-		}
-	}
-
-	defer func() {
-		logrus.Info("Stopping parent driver")
-		quit <- struct{}{}
-		if err := <-errCh; err != nil {
-			logrus.WithError(err).Warn("Parent driver returned error on exit")
-		}
-	}()
-
-	// let parent expose ports
-	logrus.Infof("Exposing ports %v", cfg.Mappings)
-	if err := exposePorts(driver, cfg.Mappings, cfg.ChildIP); err != nil {
-		return err
-	}
-
-	// we only need to have a socket to reload ports when we run under rootless cni
-	if cfg.RootlessCNI {
-		socketfile := filepath.Join(socketDir, cfg.ContainerID)
-		// make sure to remove the file if it exists to prevent EADDRINUSE
-		_ = os.Remove(socketfile)
-		// workaround to bypass the 108 char socket path limit
-		// open the fd and use the path to the fd as bind argument
-		fd, err := unix.Open(socketDir, unix.O_PATH, 0)
-		if err != nil {
-			return err
-		}
-		socket, err := net.ListenUnix("unixpacket", &net.UnixAddr{Name: fmt.Sprintf("/proc/self/fd/%d/%s", fd, cfg.ContainerID), Net: "unixpacket"})
-		if err != nil {
-			return err
-		}
-		err = unix.Close(fd)
-		// remove the socket file on exit
-		defer os.Remove(socketfile)
-		if err != nil {
-			logrus.Warnf("Failed to close the socketDir fd: %v", err)
-		}
-		defer socket.Close()
-		go serve(socket, driver)
-	}
-
-	logrus.Info("Ready")
-
-	// https://github.com/containers/podman/issues/11248
-	// Copy /dev/null to stdout and stderr to prevent SIGPIPE errors
-	if f, err := os.OpenFile("/dev/null", os.O_WRONLY, 0755); err == nil {
-		unix.Dup2(int(f.Fd()), 1) // nolint:errcheck
-		unix.Dup2(int(f.Fd()), 2) // nolint:errcheck
-		f.Close()
-	}
-	// write and close ReadyFD (convention is same as slirp4netns --ready-fd)
-	if _, err := readyW.Write([]byte("1")); err != nil {
-		return err
-	}
-	if err := readyW.Close(); err != nil {
-		return err
-	}
-
-	// wait for ExitFD to be closed
-	logrus.Info("Waiting for exitfd to be closed")
-	if _, err := ioutil.ReadAll(exitR); err != nil {
-		return err
-	}
-	return nil
-}
-
-func serve(listener net.Listener, pm rkport.Manager) {
-	for {
-		conn, err := listener.Accept()
-		if err != nil {
-			// we cannot log this error, stderr is already closed
-			continue
-		}
-		ctx := context.TODO()
-		err = handler(ctx, conn, pm)
-		if err != nil {
-			conn.Write([]byte(err.Error()))
-		} else {
-			conn.Write([]byte("OK"))
-		}
-		conn.Close()
-	}
-}
-
-func handler(ctx context.Context, conn io.Reader, pm rkport.Manager) error {
-	var childIP string
-	dec := json.NewDecoder(conn)
-	err := dec.Decode(&childIP)
-	if err != nil {
-		return errors.Wrap(err, "rootless port failed to decode ports")
-	}
-	portStatus, err := pm.ListPorts(ctx)
-	if err != nil {
-		return errors.Wrap(err, "rootless port failed to list ports")
-	}
-	for _, status := range portStatus {
-		err = pm.RemovePort(ctx, status.ID)
-		if err != nil {
-			return errors.Wrap(err, "rootless port failed to remove port")
-		}
-	}
-	// add the ports with the new child IP
-	for _, status := range portStatus {
-		// set the new child IP
-		status.Spec.ChildIP = childIP
-		_, err = pm.AddPort(ctx, status.Spec)
-		if err != nil {
-			return errors.Wrap(err, "rootless port failed to add port")
-		}
-	}
-	return nil
-}
-
-func exposePorts(pm rkport.Manager, portMappings []types.OCICNIPortMapping, childIP string) error {
-	ctx := context.TODO()
-	for _, i := range portMappings {
-		hostIP := i.HostIP
-		if hostIP == "" {
-			hostIP = "0.0.0.0"
-		}
-		spec := rkport.Spec{
-			Proto:      i.Protocol,
-			ParentIP:   hostIP,
-			ParentPort: int(i.HostPort),
-			ChildPort:  int(i.ContainerPort),
-			ChildIP:    childIP,
-		}
-		if err := rkportutil.ValidatePortSpec(spec, nil); err != nil {
-			return err
-		}
-		if _, err := pm.AddPort(ctx, spec); err != nil {
-			return err
-		}
-	}
-	return nil
-}
-
-func child() error {
-	// load the config from the parent
-	var opaque map[string]string
-	if err := json.Unmarshal([]byte(os.Getenv(reexecChildEnvOpaque)), &opaque); err != nil {
-		return err
-	}
-
-	// start the child driver
-	quit := make(chan struct{})
-	errCh := make(chan error)
-	go func() {
-		d := rkbuiltin.NewChildDriver(os.Stderr)
-		dErr := d.RunChildDriver(opaque, quit)
-		errCh <- dErr
-	}()
-	defer func() {
-		logrus.Info("Stopping child driver")
-		quit <- struct{}{}
-		if err := <-errCh; err != nil {
-			logrus.WithError(err).Warn("Child driver returned error on exit")
-		}
-	}()
-
-	// wait for stdin to be closed
-	if _, err := ioutil.ReadAll(os.Stdin); err != nil {
-		return err
-	}
-	return nil
-}
-
-type logrusWriter struct {
-	prefix string
-}
-
-func (w *logrusWriter) Write(p []byte) (int, error) {
-	logrus.Infof("%s%s", w.prefix, string(p))
-	return len(p), nil
-}