add container lib

Signed-off-by: Jess Frazelle <acidburn@microsoft.com>
This commit is contained in:
Jess Frazelle 2018-03-19 22:54:29 -04:00
parent d3fbdd212e
commit 7743701943
10 changed files with 445 additions and 397 deletions

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@ -1,6 +1,8 @@
# binctr
[![Build Status](https://travis-ci.org/genuinetools/binctr.svg?branch=master)](https://travis-ci.org/genuinetools/binctr)
[![Go Report Card](https://goreportcard.com/badge/github.com/genuinetools/binctr)](https://goreportcard.com/report/github.com/genuinetools/binctr)
[![GoDoc](https://godoc.org/github.com/genuinetools/binctr?status.svg)](https://godoc.org/github.com/genuinetools/binctr)
Create fully static, including rootfs embedded, binaries that pop you directly
into a container. **Can be run by an unprivileged user.**

135
container/container.go Normal file
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@ -0,0 +1,135 @@
// Package container allows for running a process in a container.
package container
import (
"fmt"
"os"
"os/exec"
"path/filepath"
"github.com/coreos/go-systemd/activation"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
"github.com/opencontainers/runc/libcontainer/specconv"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
// Container defines the behavior and settings for a container object.
type Container struct {
ID string
Spec *specs.Spec
PIDFile string
ConsoleSocket string
Root string
Detach bool
UseSystemdCgroup bool
NoPivotRoot bool
NoNewKeyring bool
Rootless bool
}
// Run starts the container. It returns the exit status or -1 and an
// error. Signals sent to the current process will be forwarded to container.
func (c *Container) Run() (int, error) {
var err error
// Convert pid-file to an absolute path so we can write to the
// right file after chdir to bundle.
if c.PIDFile != "" {
c.PIDFile, err = filepath.Abs(c.PIDFile)
if err != nil {
return -1, err
}
}
// Get the absolute path to the root.
c.Root, err = filepath.Abs(c.Root)
if err != nil {
return -1, err
}
notifySocket := newNotifySocket(c.ID, c.Root)
if notifySocket != nil {
// Setup the spec for the notify socket.
notifySocket.setupSpec(c.Spec)
}
// Create the libcontainer config.
config, err := specconv.CreateLibcontainerConfig(&specconv.CreateOpts{
CgroupName: c.ID,
UseSystemdCgroup: c.UseSystemdCgroup,
NoPivotRoot: c.NoPivotRoot,
NoNewKeyring: c.NoNewKeyring,
Spec: c.Spec,
Rootless: c.Rootless,
})
if err != nil {
return -1, err
}
// Setup the cgroups manager. Default is cgroupfs.
cgroupManager := libcontainer.Cgroupfs
if c.UseSystemdCgroup {
if systemd.UseSystemd() {
cgroupManager = libcontainer.SystemdCgroups
} else {
return -1, fmt.Errorf("systemd cgroup flag passed, but systemd support for managing cgroups is not available")
}
}
// We resolve the paths for {newuidmap,newgidmap} from the context of runc,
// to avoid doing a path lookup in the nsexec context. TODO: The binary
// names are not currently configurable.
newuidmap, err := exec.LookPath("newuidmap")
if err != nil {
newuidmap = ""
}
newgidmap, err := exec.LookPath("newgidmap")
if err != nil {
newgidmap = ""
}
// Create the new libcontainer factory.
factory, err := libcontainer.New(c.Root, cgroupManager, nil, nil,
libcontainer.NewuidmapPath(newuidmap),
libcontainer.NewgidmapPath(newgidmap))
if err != nil {
return -1, err
}
// Create the factory.
container, err := factory.Create(c.ID, config)
if err != nil {
return -1, err
}
if notifySocket != nil {
// Setup the socket for the notify socket.
err := notifySocket.setupSocket()
if err != nil {
return -1, err
}
}
// Support on-demand socket activation by passing file descriptors into
// the container init process.
listenFDs := []*os.File{}
if os.Getenv("LISTEN_FDS") != "" {
listenFDs = activation.Files(false)
}
// Initialize the runner.
r := &runner{
enableSubreaper: true,
shouldDestroy: true,
container: container,
listenFDs: listenFDs,
notifySocket: notifySocket,
consoleSocket: c.ConsoleSocket,
detach: c.Detach,
pidFile: c.PIDFile,
}
// Run the process.
return r.run(c.Spec.Process)
}

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@ -1,4 +1,4 @@
package main
package container
import (
"bytes"

143
container/process.go Normal file
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@ -0,0 +1,143 @@
package container
import (
"fmt"
"net"
"os"
"path/filepath"
"strconv"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/utils"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/sirupsen/logrus"
)
// newProcess returns a new libcontainer Process with the arguments from the
// spec and stdio from the current process.
func newProcess(p specs.Process) (*libcontainer.Process, error) {
// Create the libcontainer process.
lp := &libcontainer.Process{
Args: p.Args,
Env: p.Env,
User: fmt.Sprintf("%d:%d", p.User.UID, p.User.GID),
Cwd: p.Cwd,
Label: p.SelinuxLabel,
NoNewPrivileges: &p.NoNewPrivileges,
AppArmorProfile: p.ApparmorProfile,
}
// Setup the console size.
if p.ConsoleSize != nil {
lp.ConsoleWidth = uint16(p.ConsoleSize.Width)
lp.ConsoleHeight = uint16(p.ConsoleSize.Height)
}
// Convert the capabilities.
if p.Capabilities != nil {
lp.Capabilities = &configs.Capabilities{}
lp.Capabilities.Bounding = p.Capabilities.Bounding
lp.Capabilities.Effective = p.Capabilities.Effective
lp.Capabilities.Inheritable = p.Capabilities.Inheritable
lp.Capabilities.Permitted = p.Capabilities.Permitted
lp.Capabilities.Ambient = p.Capabilities.Ambient
}
// Setup the additional user groups.
for _, gid := range p.User.AdditionalGids {
lp.AdditionalGroups = append(lp.AdditionalGroups, strconv.FormatUint(uint64(gid), 10))
}
// Setup the Rlimits.
for _, rlimit := range p.Rlimits {
rl, err := createLibContainerRlimit(rlimit)
if err != nil {
return nil, err
}
lp.Rlimits = append(lp.Rlimits, rl)
}
return lp, nil
}
func destroy(container libcontainer.Container) {
if err := container.Destroy(); err != nil {
logrus.Error(err)
}
}
func setupIO(process *libcontainer.Process, rootuid, rootgid int, createTTY, detach bool, sockpath string) (*tty, error) {
if createTTY {
process.Stdin = nil
process.Stdout = nil
process.Stderr = nil
t := &tty{}
if !detach {
parent, child, err := utils.NewSockPair("console")
if err != nil {
return nil, err
}
process.ConsoleSocket = child
t.postStart = append(t.postStart, parent, child)
t.consoleC = make(chan error, 1)
go func() {
if err := t.recvtty(process, parent); err != nil {
t.consoleC <- err
}
t.consoleC <- nil
}()
} else {
// the caller of runc will handle receiving the console master
conn, err := net.Dial("unix", sockpath)
if err != nil {
return nil, err
}
uc, ok := conn.(*net.UnixConn)
if !ok {
return nil, fmt.Errorf("casting to UnixConn failed")
}
t.postStart = append(t.postStart, uc)
socket, err := uc.File()
if err != nil {
return nil, err
}
t.postStart = append(t.postStart, socket)
process.ConsoleSocket = socket
}
return t, nil
}
// when runc will detach the caller provides the stdio to runc via runc's 0,1,2
// and the container's process inherits runc's stdio.
if detach {
if err := inheritStdio(process); err != nil {
return nil, err
}
return &tty{}, nil
}
return setupProcessPipes(process, rootuid, rootgid)
}
// createPidFile creates a file with the processes pid inside it atomically
// it creates a temp file with the paths filename + '.' infront of it
// then renames the file
func createPidFile(path string, process *libcontainer.Process) error {
pid, err := process.Pid()
if err != nil {
return err
}
var (
tmpDir = filepath.Dir(path)
tmpName = filepath.Join(tmpDir, fmt.Sprintf(".%s", filepath.Base(path)))
)
f, err := os.OpenFile(tmpName, os.O_RDWR|os.O_CREATE|os.O_EXCL|os.O_SYNC, 0666)
if err != nil {
return err
}
_, err = fmt.Fprintf(f, "%d", pid)
f.Close()
if err != nil {
return err
}
return os.Rename(tmpName, path)
}

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@ -1,6 +1,11 @@
package main
package container
import "fmt"
import (
"fmt"
"github.com/opencontainers/runc/libcontainer/configs"
specs "github.com/opencontainers/runtime-spec/specs-go"
)
const (
rLimitCPU = iota // CPU time in sec
@ -47,3 +52,15 @@ func strToRlimit(key string) (int, error) {
}
return rl, nil
}
func createLibContainerRlimit(rlimit specs.POSIXRlimit) (configs.Rlimit, error) {
rl, err := strToRlimit(rlimit.Type)
if err != nil {
return configs.Rlimit{}, err
}
return configs.Rlimit{
Type: rl,
Hard: rlimit.Hard,
Soft: rlimit.Soft,
}, nil
}

129
container/runner.go Normal file
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@ -0,0 +1,129 @@
package container
import (
"fmt"
"os"
"github.com/opencontainers/runc/libcontainer"
specs "github.com/opencontainers/runtime-spec/specs-go"
"golang.org/x/sys/unix"
)
type runner struct {
enableSubreaper bool
detach bool
shouldDestroy bool
consoleSocket string
pidFile string
container libcontainer.Container
listenFDs []*os.File
notifySocket *notifySocket
}
func (r *runner) run(config *specs.Process) (int, error) {
// Check the terminal settings.
if r.detach && config.Terminal && r.consoleSocket == "" {
return -1, fmt.Errorf("cannot allocate tty if runc will detach without setting console socket")
}
if (!r.detach || !config.Terminal) && r.consoleSocket != "" {
return -1, fmt.Errorf("cannot use console socket if runc will not detach or allocate tty")
}
// Create the process.
process, err := newProcess(*config)
if err != nil {
r.destroy()
return -1, err
}
// Setup the listen file descriptors.
if len(r.listenFDs) > 0 {
process.Env = append(process.Env, fmt.Sprintf("LISTEN_FDS=%d", len(r.listenFDs)), "LISTEN_PID=1")
process.ExtraFiles = append(process.ExtraFiles, r.listenFDs...)
}
// Get the rootuid.
rootuid, err := r.container.Config().HostRootUID()
if err != nil {
r.destroy()
return -1, err
}
// Get the rootgid.
rootgid, err := r.container.Config().HostRootGID()
if err != nil {
r.destroy()
return -1, err
}
// Setting up IO is a two stage process. We need to modify process to deal
// with detaching containers, and then we get a tty after the container has
// started.
handler := newSignalHandler(r.enableSubreaper, r.notifySocket)
tty, err := setupIO(process, rootuid, rootgid, config.Terminal, r.detach, r.consoleSocket)
if err != nil {
r.destroy()
return -1, err
}
defer tty.Close()
// Run the container.
if err := r.container.Run(process); err != nil {
r.destroy()
tty.Close()
return -1, err
}
// Wait for the tty.
if err := tty.waitConsole(); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
// Close after start the tty.
if err = tty.ClosePostStart(); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
// Create the pid file.
if r.pidFile != "" {
if err := createPidFile(r.pidFile, process); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
}
// Forward the handler.
status, err := handler.forward(process, tty, r.detach)
if err != nil {
r.terminate(process)
}
// Return early if we are detaching.
if r.detach {
return 0, nil
}
// Cleanup.
r.destroy()
return status, err
}
func (r *runner) destroy() {
if r.shouldDestroy {
destroy(r.container)
}
}
func (r *runner) terminate(p *libcontainer.Process) {
_ = p.Signal(unix.SIGKILL)
_, _ = p.Wait()
}

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@ -1,4 +1,4 @@
package main
package container
import (
"os"

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@ -1,4 +1,4 @@
package main
package container
import (
"fmt"

32
main.go
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@ -5,11 +5,11 @@ import (
"fmt"
"os"
"os/exec"
"path/filepath"
"runtime"
"strings"
aaprofile "github.com/docker/docker/profiles/apparmor"
"github.com/genuinetools/binctr/container"
"github.com/genuinetools/binctr/image"
"github.com/genuinetools/binctr/version"
"github.com/opencontainers/runc/libcontainer"
@ -142,21 +142,6 @@ func init() {
logrus.Fatal(err)
}
// Convert pid-file to an absolute path so we can write to the
// right file after chdir to bundle.
if pidFile != "" {
pidFile, err = filepath.Abs(pidFile)
if err != nil {
logrus.Fatal(err)
}
}
// Get the absolute path to the root.
root, err = filepath.Abs(root)
if err != nil {
logrus.Fatal(err)
}
}
//go:generate go run generate.go
@ -199,8 +184,19 @@ func main() {
logrus.Fatal(err)
}
// Start the container.
status, err := startContainer(spec, containerID, pidFile, consoleSocket, root, detach)
// Initialize the container object.
c := &container.Container{
ID: containerID,
Spec: spec,
PIDFile: pidFile,
ConsoleSocket: consoleSocket,
Root: root,
Detach: detach,
Rootless: true,
}
// Run the container.
status, err := c.Run()
if err != nil {
logrus.Fatal(err)
}

374
utils.go
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@ -1,374 +0,0 @@
package main
import (
"fmt"
"net"
"os"
"os/exec"
"path/filepath"
"strconv"
"github.com/coreos/go-systemd/activation"
"github.com/opencontainers/runc/libcontainer"
"github.com/opencontainers/runc/libcontainer/cgroups/systemd"
"github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/specconv"
"github.com/opencontainers/runc/libcontainer/utils"
specs "github.com/opencontainers/runtime-spec/specs-go"
"github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
)
// startContainer starts the container. Returns the exit status or -1 and an
// error. Signals sent to the current process will be forwarded to container.
func startContainer(spec *specs.Spec, id, pidFile, consoleSocket, root string, detach bool) (int, error) {
notifySocket := newNotifySocket(id, root)
if notifySocket != nil {
// Setup the spec for the notify socket.
notifySocket.setupSpec(spec)
}
// Create the libcontainer config.
useSystemdCgroup := false
config, err := specconv.CreateLibcontainerConfig(&specconv.CreateOpts{
CgroupName: id,
UseSystemdCgroup: useSystemdCgroup,
NoPivotRoot: false,
NoNewKeyring: false,
Spec: spec,
Rootless: true,
})
if err != nil {
return -1, err
}
// Load the factory.
factory, err := loadFactory(root, useSystemdCgroup)
if err != nil {
return -1, err
}
// Create the factory.
container, err := factory.Create(id, config)
if err != nil {
return -1, err
}
if notifySocket != nil {
// Setup the socket for the notify socket.
err := notifySocket.setupSocket()
if err != nil {
return -1, err
}
}
// Support on-demand socket activation by passing file descriptors into
// the container init process.
listenFDs := []*os.File{}
if os.Getenv("LISTEN_FDS") != "" {
listenFDs = activation.Files(false)
}
// Initialize the runner.
r := &runner{
enableSubreaper: true,
shouldDestroy: true,
container: container,
listenFDs: listenFDs,
notifySocket: notifySocket,
consoleSocket: consoleSocket,
detach: detach,
pidFile: pidFile,
}
// Run the process.
return r.run(spec.Process)
}
// loadFactory returns the configured factory instance for execing containers.
func loadFactory(root string, useSystemdCgroup bool) (libcontainer.Factory, error) {
// Setup the cgroups manager. Default is cgroupfs.
cgroupManager := libcontainer.Cgroupfs
if useSystemdCgroup {
if systemd.UseSystemd() {
cgroupManager = libcontainer.SystemdCgroups
} else {
return nil, fmt.Errorf("systemd cgroup flag passed, but systemd support for managing cgroups is not available")
}
}
// We resolve the paths for {newuidmap,newgidmap} from the context of runc,
// to avoid doing a path lookup in the nsexec context. TODO: The binary
// names are not currently configurable.
newuidmap, err := exec.LookPath("newuidmap")
if err != nil {
newuidmap = ""
}
newgidmap, err := exec.LookPath("newgidmap")
if err != nil {
newgidmap = ""
}
// Create the new libcontainer factory.
return libcontainer.New(root, cgroupManager, nil, nil,
libcontainer.NewuidmapPath(newuidmap),
libcontainer.NewgidmapPath(newgidmap))
}
// newProcess returns a new libcontainer Process with the arguments from the
// spec and stdio from the current process.
func newProcess(p specs.Process) (*libcontainer.Process, error) {
// Create the libcontainer process.
lp := &libcontainer.Process{
Args: p.Args,
Env: p.Env,
User: fmt.Sprintf("%d:%d", p.User.UID, p.User.GID),
Cwd: p.Cwd,
Label: p.SelinuxLabel,
NoNewPrivileges: &p.NoNewPrivileges,
AppArmorProfile: p.ApparmorProfile,
}
// Setup the console size.
if p.ConsoleSize != nil {
lp.ConsoleWidth = uint16(p.ConsoleSize.Width)
lp.ConsoleHeight = uint16(p.ConsoleSize.Height)
}
// Convert the capabilities.
if p.Capabilities != nil {
lp.Capabilities = &configs.Capabilities{}
lp.Capabilities.Bounding = p.Capabilities.Bounding
lp.Capabilities.Effective = p.Capabilities.Effective
lp.Capabilities.Inheritable = p.Capabilities.Inheritable
lp.Capabilities.Permitted = p.Capabilities.Permitted
lp.Capabilities.Ambient = p.Capabilities.Ambient
}
// Setup the additional user groups.
for _, gid := range p.User.AdditionalGids {
lp.AdditionalGroups = append(lp.AdditionalGroups, strconv.FormatUint(uint64(gid), 10))
}
// Setup the Rlimits.
for _, rlimit := range p.Rlimits {
rl, err := createLibContainerRlimit(rlimit)
if err != nil {
return nil, err
}
lp.Rlimits = append(lp.Rlimits, rl)
}
return lp, nil
}
func destroy(container libcontainer.Container) {
if err := container.Destroy(); err != nil {
logrus.Error(err)
}
}
func setupIO(process *libcontainer.Process, rootuid, rootgid int, createTTY, detach bool, sockpath string) (*tty, error) {
if createTTY {
process.Stdin = nil
process.Stdout = nil
process.Stderr = nil
t := &tty{}
if !detach {
parent, child, err := utils.NewSockPair("console")
if err != nil {
return nil, err
}
process.ConsoleSocket = child
t.postStart = append(t.postStart, parent, child)
t.consoleC = make(chan error, 1)
go func() {
if err := t.recvtty(process, parent); err != nil {
t.consoleC <- err
}
t.consoleC <- nil
}()
} else {
// the caller of runc will handle receiving the console master
conn, err := net.Dial("unix", sockpath)
if err != nil {
return nil, err
}
uc, ok := conn.(*net.UnixConn)
if !ok {
return nil, fmt.Errorf("casting to UnixConn failed")
}
t.postStart = append(t.postStart, uc)
socket, err := uc.File()
if err != nil {
return nil, err
}
t.postStart = append(t.postStart, socket)
process.ConsoleSocket = socket
}
return t, nil
}
// when runc will detach the caller provides the stdio to runc via runc's 0,1,2
// and the container's process inherits runc's stdio.
if detach {
if err := inheritStdio(process); err != nil {
return nil, err
}
return &tty{}, nil
}
return setupProcessPipes(process, rootuid, rootgid)
}
// createPidFile creates a file with the processes pid inside it atomically
// it creates a temp file with the paths filename + '.' infront of it
// then renames the file
func createPidFile(path string, process *libcontainer.Process) error {
pid, err := process.Pid()
if err != nil {
return err
}
var (
tmpDir = filepath.Dir(path)
tmpName = filepath.Join(tmpDir, fmt.Sprintf(".%s", filepath.Base(path)))
)
f, err := os.OpenFile(tmpName, os.O_RDWR|os.O_CREATE|os.O_EXCL|os.O_SYNC, 0666)
if err != nil {
return err
}
_, err = fmt.Fprintf(f, "%d", pid)
f.Close()
if err != nil {
return err
}
return os.Rename(tmpName, path)
}
type runner struct {
enableSubreaper bool
detach bool
shouldDestroy bool
consoleSocket string
pidFile string
container libcontainer.Container
listenFDs []*os.File
notifySocket *notifySocket
}
func (r *runner) run(config *specs.Process) (int, error) {
// Check the terminal settings.
if r.detach && config.Terminal && r.consoleSocket == "" {
return -1, fmt.Errorf("cannot allocate tty if runc will detach without setting console socket")
}
if (!r.detach || !config.Terminal) && r.consoleSocket != "" {
return -1, fmt.Errorf("cannot use console socket if runc will not detach or allocate tty")
}
// Create the process.
process, err := newProcess(*config)
if err != nil {
r.destroy()
return -1, err
}
// Setup the listen file descriptors.
if len(r.listenFDs) > 0 {
process.Env = append(process.Env, fmt.Sprintf("LISTEN_FDS=%d", len(r.listenFDs)), "LISTEN_PID=1")
process.ExtraFiles = append(process.ExtraFiles, r.listenFDs...)
}
// Get the rootuid.
rootuid, err := r.container.Config().HostRootUID()
if err != nil {
r.destroy()
return -1, err
}
// Get the rootgid.
rootgid, err := r.container.Config().HostRootGID()
if err != nil {
r.destroy()
return -1, err
}
// Setting up IO is a two stage process. We need to modify process to deal
// with detaching containers, and then we get a tty after the container has
// started.
handler := newSignalHandler(r.enableSubreaper, r.notifySocket)
tty, err := setupIO(process, rootuid, rootgid, config.Terminal, r.detach, r.consoleSocket)
if err != nil {
r.destroy()
return -1, err
}
defer tty.Close()
// Run the container.
if err := r.container.Run(process); err != nil {
r.destroy()
tty.Close()
return -1, err
}
// Wait for the tty.
if err := tty.waitConsole(); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
// Close after start the tty.
if err = tty.ClosePostStart(); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
// Create the pid file.
if r.pidFile != "" {
if err := createPidFile(r.pidFile, process); err != nil {
r.terminate(process)
r.destroy()
tty.Close()
return -1, err
}
}
// Forward the handler.
status, err := handler.forward(process, tty, detach)
if err != nil {
r.terminate(process)
}
// Return early if we are detaching.
if r.detach {
return 0, nil
}
// Cleanup.
r.destroy()
return status, err
}
func (r *runner) destroy() {
if r.shouldDestroy {
destroy(r.container)
}
}
func (r *runner) terminate(p *libcontainer.Process) {
_ = p.Signal(unix.SIGKILL)
_, _ = p.Wait()
}
func createLibContainerRlimit(rlimit specs.POSIXRlimit) (configs.Rlimit, error) {
rl, err := strToRlimit(rlimit.Type)
if err != nil {
return configs.Rlimit{}, err
}
return configs.Rlimit{
Type: rl,
Hard: rlimit.Hard,
Soft: rlimit.Soft,
}, nil
}