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run_linux.go
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run_linux.go
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// +build linux
package buildah
import (
"bytes"
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"net"
"os"
"os/exec"
"path/filepath"
"runtime"
"strconv"
"strings"
"sync"
"syscall"
"time"
"github.com/containernetworking/cni/libcni"
"github.com/containers/buildah/bind"
"github.com/containers/buildah/chroot"
"github.com/containers/buildah/pkg/overlay"
"github.com/containers/buildah/pkg/secrets"
"github.com/containers/buildah/util"
"github.com/containers/common/pkg/capabilities"
"github.com/containers/common/pkg/config"
"github.com/containers/storage/pkg/idtools"
"github.com/containers/storage/pkg/ioutils"
"github.com/containers/storage/pkg/reexec"
"github.com/containers/storage/pkg/stringid"
"github.com/containers/storage/pkg/unshare"
"github.com/docker/go-units"
"github.com/docker/libnetwork/resolvconf"
"github.com/docker/libnetwork/types"
"github.com/opencontainers/go-digest"
"github.com/opencontainers/runtime-spec/specs-go"
spec "github.com/opencontainers/runtime-spec/specs-go"
"github.com/opencontainers/runtime-tools/generate"
"github.com/opencontainers/selinux/go-selinux/label"
"github.com/pkg/errors"
"github.com/sirupsen/logrus"
"golang.org/x/crypto/ssh/terminal"
"golang.org/x/sys/unix"
)
func setChildProcess() error {
if err := unix.Prctl(unix.PR_SET_CHILD_SUBREAPER, uintptr(1), 0, 0, 0); err != nil {
fmt.Fprintf(os.Stderr, "prctl(PR_SET_CHILD_SUBREAPER, 1): %v\n", err)
return err
}
return nil
}
// Run runs the specified command in the container's root filesystem.
func (b *Builder) Run(command []string, options RunOptions) error {
p, err := ioutil.TempDir("", Package)
if err != nil {
return errors.Wrapf(err, "run: error creating temporary directory under %q", os.TempDir())
}
// On some hosts like AH, /tmp is a symlink and we need an
// absolute path.
path, err := filepath.EvalSymlinks(p)
if err != nil {
return errors.Wrapf(err, "run: error evaluating %q for symbolic links", p)
}
logrus.Debugf("using %q to hold bundle data", path)
defer func() {
if err2 := os.RemoveAll(path); err2 != nil {
logrus.Errorf("error removing %q: %v", path, err2)
}
}()
gp, err := generate.New("linux")
if err != nil {
return errors.Wrapf(err, "error generating new 'linux' runtime spec")
}
g := &gp
isolation := options.Isolation
if isolation == IsolationDefault {
isolation = b.Isolation
if isolation == IsolationDefault {
isolation = IsolationOCI
}
}
if err := checkAndOverrideIsolationOptions(isolation, &options); err != nil {
return err
}
defaultContainerConfig, err := config.Default()
if err != nil {
return errors.Wrapf(err, "failed to get container config")
}
b.configureEnvironment(g, options, defaultContainerConfig.Containers.Env)
if b.CommonBuildOpts == nil {
return errors.Errorf("Invalid format on container you must recreate the container")
}
if err := addCommonOptsToSpec(b.CommonBuildOpts, g); err != nil {
return err
}
if options.WorkingDir != "" {
g.SetProcessCwd(options.WorkingDir)
} else if b.WorkDir() != "" {
g.SetProcessCwd(b.WorkDir())
}
setupSelinux(g, b.ProcessLabel, b.MountLabel)
mountPoint, err := b.Mount(b.MountLabel)
if err != nil {
return errors.Wrapf(err, "error mounting container %q", b.ContainerID)
}
defer func() {
if err := b.Unmount(); err != nil {
logrus.Errorf("error unmounting container: %v", err)
}
}()
g.SetRootPath(mountPoint)
if len(command) > 0 {
command = runLookupPath(g, command)
g.SetProcessArgs(command)
} else {
g.SetProcessArgs(nil)
}
for _, d := range b.Devices {
sDev := spec.LinuxDevice{
Type: string(d.Type),
Path: d.Path,
Major: d.Major,
Minor: d.Minor,
FileMode: &d.FileMode,
UID: &d.Uid,
GID: &d.Gid,
}
g.AddDevice(sDev)
g.AddLinuxResourcesDevice(true, string(d.Type), &d.Major, &d.Minor, string(d.Permissions))
}
setupMaskedPaths(g)
setupReadOnlyPaths(g)
setupTerminal(g, options.Terminal, options.TerminalSize)
configureNetwork, configureNetworks, err := b.configureNamespaces(g, options)
if err != nil {
return err
}
homeDir, err := b.configureUIDGID(g, mountPoint, options)
if err != nil {
return err
}
g.SetProcessApparmorProfile(b.CommonBuildOpts.ApparmorProfile)
// Now grab the spec from the generator. Set the generator to nil so that future contributors
// will quickly be able to tell that they're supposed to be modifying the spec directly from here.
spec := g.Config
g = nil
logrus.Debugf("ensuring working directory %q exists", filepath.Join(mountPoint, spec.Process.Cwd))
if err = os.MkdirAll(filepath.Join(mountPoint, spec.Process.Cwd), 0755); err != nil && !os.IsExist(err) {
return errors.Wrapf(err, "error ensuring working directory %q exists", spec.Process.Cwd)
}
// Set the seccomp configuration using the specified profile name. Some syscalls are
// allowed if certain capabilities are to be granted (example: CAP_SYS_CHROOT and chroot),
// so we sorted out the capabilities lists first.
if err = setupSeccomp(spec, b.CommonBuildOpts.SeccompProfilePath); err != nil {
return err
}
// Figure out who owns files that will appear to be owned by UID/GID 0 in the container.
rootUID, rootGID, err := util.GetHostRootIDs(spec)
if err != nil {
return err
}
rootIDPair := &idtools.IDPair{UID: int(rootUID), GID: int(rootGID)}
bindFiles := make(map[string]string)
namespaceOptions := append(b.NamespaceOptions, options.NamespaceOptions...)
volumes := b.Volumes()
if !contains(volumes, "/etc/hosts") {
hostFile, err := b.generateHosts(path, spec.Hostname, b.CommonBuildOpts.AddHost, rootIDPair)
if err != nil {
return err
}
// Only bind /etc/hosts if there's a network
if options.ConfigureNetwork != NetworkDisabled {
bindFiles["/etc/hosts"] = hostFile
}
}
if !(contains(volumes, "/etc/resolv.conf") || (len(b.CommonBuildOpts.DNSServers) == 1 && strings.ToLower(b.CommonBuildOpts.DNSServers[0]) == "none")) {
resolvFile, err := b.addNetworkConfig(path, "/etc/resolv.conf", rootIDPair, b.CommonBuildOpts.DNSServers, b.CommonBuildOpts.DNSSearch, b.CommonBuildOpts.DNSOptions, namespaceOptions)
if err != nil {
return err
}
// Only bind /etc/resolv.conf if there's a network
if options.ConfigureNetwork != NetworkDisabled {
bindFiles["/etc/resolv.conf"] = resolvFile
}
}
// Empty file, so no need to recreate if it exists
if _, ok := bindFiles["/run/.containerenv"]; !ok {
// Empty string for now, but we may consider populating this later
containerenvPath := filepath.Join(path, "/run/.containerenv")
if err = os.MkdirAll(filepath.Dir(containerenvPath), 0755); err != nil && !os.IsExist(err) {
return err
}
emptyFile, err := os.Create(containerenvPath)
if err != nil {
return err
}
emptyFile.Close()
if err := label.Relabel(containerenvPath, b.MountLabel, false); err != nil {
return errors.Wrapf(err, "error relabeling %q in container %q", containerenvPath, b.ContainerID)
}
bindFiles["/run/.containerenv"] = containerenvPath
}
err = b.setupMounts(mountPoint, spec, path, options.Mounts, bindFiles, volumes, b.CommonBuildOpts.Volumes, b.CommonBuildOpts.ShmSize, namespaceOptions)
if err != nil {
return errors.Wrapf(err, "error resolving mountpoints for container %q", b.ContainerID)
}
defer b.cleanupTempVolumes()
if options.CNIConfigDir == "" {
options.CNIConfigDir = b.CNIConfigDir
if b.CNIConfigDir == "" {
options.CNIConfigDir = util.DefaultCNIConfigDir
}
}
if options.CNIPluginPath == "" {
options.CNIPluginPath = b.CNIPluginPath
if b.CNIPluginPath == "" {
options.CNIPluginPath = util.DefaultCNIPluginPath
}
}
switch isolation {
case IsolationOCI:
var moreCreateArgs []string
if options.NoPivot {
moreCreateArgs = []string{"--no-pivot"}
} else {
moreCreateArgs = nil
}
err = b.runUsingRuntimeSubproc(isolation, options, configureNetwork, configureNetworks, moreCreateArgs, spec, mountPoint, path, Package+"-"+filepath.Base(path))
case IsolationChroot:
err = chroot.RunUsingChroot(spec, path, homeDir, options.Stdin, options.Stdout, options.Stderr)
case IsolationOCIRootless:
moreCreateArgs := []string{"--no-new-keyring"}
if options.NoPivot {
moreCreateArgs = append(moreCreateArgs, "--no-pivot")
}
if err := setupRootlessSpecChanges(spec, path, b.CommonBuildOpts.ShmSize); err != nil {
return err
}
err = b.runUsingRuntimeSubproc(isolation, options, configureNetwork, configureNetworks, moreCreateArgs, spec, mountPoint, path, Package+"-"+filepath.Base(path))
default:
err = errors.Errorf("don't know how to run this command")
}
return err
}
func addCommonOptsToSpec(commonOpts *CommonBuildOptions, g *generate.Generator) error {
// Resources - CPU
if commonOpts.CPUPeriod != 0 {
g.SetLinuxResourcesCPUPeriod(commonOpts.CPUPeriod)
}
if commonOpts.CPUQuota != 0 {
g.SetLinuxResourcesCPUQuota(commonOpts.CPUQuota)
}
if commonOpts.CPUShares != 0 {
g.SetLinuxResourcesCPUShares(commonOpts.CPUShares)
}
if commonOpts.CPUSetCPUs != "" {
g.SetLinuxResourcesCPUCpus(commonOpts.CPUSetCPUs)
}
if commonOpts.CPUSetMems != "" {
g.SetLinuxResourcesCPUMems(commonOpts.CPUSetMems)
}
// Resources - Memory
if commonOpts.Memory != 0 {
g.SetLinuxResourcesMemoryLimit(commonOpts.Memory)
}
if commonOpts.MemorySwap != 0 {
g.SetLinuxResourcesMemorySwap(commonOpts.MemorySwap)
}
// cgroup membership
if commonOpts.CgroupParent != "" {
g.SetLinuxCgroupsPath(commonOpts.CgroupParent)
}
defaultContainerConfig, err := config.Default()
if err != nil {
return errors.Wrapf(err, "failed to get container config")
}
// Other process resource limits
if err := addRlimits(commonOpts.Ulimit, g, defaultContainerConfig.Containers.DefaultUlimits); err != nil {
return err
}
logrus.Debugf("Resources: %#v", commonOpts)
return nil
}
func runSetupBuiltinVolumes(mountLabel, mountPoint, containerDir string, copyWithTar func(srcPath, dstPath string) error, builtinVolumes []string, rootUID, rootGID int) ([]specs.Mount, error) {
var mounts []specs.Mount
hostOwner := idtools.IDPair{UID: rootUID, GID: rootGID}
// Add temporary copies of the contents of volume locations at the
// volume locations, unless we already have something there.
for _, volume := range builtinVolumes {
subdir := digest.Canonical.FromString(volume).Hex()
volumePath := filepath.Join(containerDir, "buildah-volumes", subdir)
srcPath := filepath.Join(mountPoint, volume)
initializeVolume := false
// If we need to, initialize the volume path's initial contents.
if _, err := os.Stat(volumePath); err != nil {
if !os.IsNotExist(err) {
return nil, errors.Wrapf(err, "failed to stat %q for volume %q", volumePath, volume)
}
logrus.Debugf("setting up built-in volume at %q", volumePath)
if err = os.MkdirAll(volumePath, 0755); err != nil {
return nil, errors.Wrapf(err, "error creating directory %q for volume %q", volumePath, volume)
}
if err = label.Relabel(volumePath, mountLabel, false); err != nil {
return nil, errors.Wrapf(err, "error relabeling directory %q for volume %q", volumePath, volume)
}
initializeVolume = true
}
stat, err := os.Stat(srcPath)
if err != nil {
if !os.IsNotExist(err) {
return nil, errors.Wrapf(err, "failed to stat %q for volume %q", srcPath, volume)
}
if err = idtools.MkdirAllAndChownNew(srcPath, 0755, hostOwner); err != nil {
return nil, errors.Wrapf(err, "error creating directory %q for volume %q", srcPath, volume)
}
if stat, err = os.Stat(srcPath); err != nil {
return nil, errors.Wrapf(err, "failed to stat %q for volume %q", srcPath, volume)
}
}
if initializeVolume {
if err = os.Chmod(volumePath, stat.Mode().Perm()); err != nil {
return nil, errors.Wrapf(err, "failed to chmod %q for volume %q", volumePath, volume)
}
if err = os.Chown(volumePath, int(stat.Sys().(*syscall.Stat_t).Uid), int(stat.Sys().(*syscall.Stat_t).Gid)); err != nil {
return nil, errors.Wrapf(err, "error chowning directory %q for volume %q", volumePath, volume)
}
if err = copyWithTar(srcPath, volumePath); err != nil && !os.IsNotExist(errors.Cause(err)) {
return nil, errors.Wrapf(err, "error populating directory %q for volume %q using contents of %q", volumePath, volume, srcPath)
}
}
// Add the bind mount.
mounts = append(mounts, specs.Mount{
Source: volumePath,
Destination: volume,
Type: "bind",
Options: []string{"bind"},
})
}
return mounts, nil
}
func (b *Builder) setupMounts(mountPoint string, spec *specs.Spec, bundlePath string, optionMounts []specs.Mount, bindFiles map[string]string, builtinVolumes, volumeMounts []string, shmSize string, namespaceOptions NamespaceOptions) error {
// Start building a new list of mounts.
var mounts []specs.Mount
haveMount := func(destination string) bool {
for _, mount := range mounts {
if mount.Destination == destination {
// Already have something to mount there.
return true
}
}
return false
}
ipc := namespaceOptions.Find(string(specs.IPCNamespace))
hostIPC := ipc == nil || ipc.Host
net := namespaceOptions.Find(string(specs.NetworkNamespace))
hostNetwork := net == nil || net.Host
user := namespaceOptions.Find(string(specs.UserNamespace))
hostUser := (user == nil || user.Host) && !unshare.IsRootless()
// Copy mounts from the generated list.
mountCgroups := true
specMounts := []specs.Mount{}
for _, specMount := range spec.Mounts {
// Override some of the mounts from the generated list if we're doing different things with namespaces.
if specMount.Destination == "/dev/shm" {
specMount.Options = []string{"nosuid", "noexec", "nodev", "mode=1777"}
if shmSize != "" {
specMount.Options = append(specMount.Options, "size="+shmSize)
}
if hostIPC && !hostUser {
if _, err := os.Stat("/dev/shm"); err != nil && os.IsNotExist(err) {
logrus.Debugf("/dev/shm is not present, not binding into container")
continue
}
specMount = specs.Mount{
Source: "/dev/shm",
Type: "bind",
Destination: "/dev/shm",
Options: []string{bind.NoBindOption, "rbind", "nosuid", "noexec", "nodev"},
}
}
}
if specMount.Destination == "/dev/mqueue" {
if hostIPC && !hostUser {
if _, err := os.Stat("/dev/mqueue"); err != nil && os.IsNotExist(err) {
logrus.Debugf("/dev/mqueue is not present, not binding into container")
continue
}
specMount = specs.Mount{
Source: "/dev/mqueue",
Type: "bind",
Destination: "/dev/mqueue",
Options: []string{bind.NoBindOption, "rbind", "nosuid", "noexec", "nodev"},
}
}
}
if specMount.Destination == "/sys" {
if hostNetwork && !hostUser {
mountCgroups = false
if _, err := os.Stat("/sys"); err != nil && os.IsNotExist(err) {
logrus.Debugf("/sys is not present, not binding into container")
continue
}
specMount = specs.Mount{
Source: "/sys",
Type: "bind",
Destination: "/sys",
Options: []string{bind.NoBindOption, "rbind", "nosuid", "noexec", "nodev", "ro"},
}
}
}
specMounts = append(specMounts, specMount)
}
// Add a mount for the cgroups filesystem, unless we're already
// recursively bind mounting all of /sys, in which case we shouldn't
// bother with it.
sysfsMount := []specs.Mount{}
if mountCgroups {
sysfsMount = []specs.Mount{{
Destination: "/sys/fs/cgroup",
Type: "cgroup",
Source: "cgroup",
Options: []string{bind.NoBindOption, "nosuid", "noexec", "nodev", "relatime", "ro"},
}}
}
// Get the list of files we need to bind into the container.
bindFileMounts := runSetupBoundFiles(bundlePath, bindFiles)
// After this point we need to know the per-container persistent storage directory.
cdir, err := b.store.ContainerDirectory(b.ContainerID)
if err != nil {
return errors.Wrapf(err, "error determining work directory for container %q", b.ContainerID)
}
// Figure out which UID and GID to tell the secrets package to use
// for files that it creates.
rootUID, rootGID, err := util.GetHostRootIDs(spec)
if err != nil {
return err
}
// Get the list of secrets mounts.
secretMounts := secrets.SecretMountsWithUIDGID(b.MountLabel, cdir, b.DefaultMountsFilePath, mountPoint, int(rootUID), int(rootGID), unshare.IsRootless(), false)
// Add temporary copies of the contents of volume locations at the
// volume locations, unless we already have something there.
copyWithTar := b.copyWithTar(nil, nil, nil, false)
builtins, err := runSetupBuiltinVolumes(b.MountLabel, mountPoint, cdir, copyWithTar, builtinVolumes, int(rootUID), int(rootGID))
if err != nil {
return err
}
// Get the list of explicitly-specified volume mounts.
volumes, err := b.runSetupVolumeMounts(spec.Linux.MountLabel, volumeMounts, optionMounts, int(rootUID), int(rootGID))
if err != nil {
return err
}
// Add them all, in the preferred order, except where they conflict with something that was previously added.
for _, mount := range append(append(append(append(append(volumes, builtins...), secretMounts...), bindFileMounts...), specMounts...), sysfsMount...) {
if haveMount(mount.Destination) {
// Already mounting something there, no need to bother with this one.
continue
}
// Add the mount.
mounts = append(mounts, mount)
}
// Set the list in the spec.
spec.Mounts = mounts
return nil
}
// addNetworkConfig copies files from host and sets them up to bind mount into container
func (b *Builder) addNetworkConfig(rdir, hostPath string, chownOpts *idtools.IDPair, dnsServers, dnsSearch, dnsOptions []string, namespaceOptions NamespaceOptions) (string, error) {
stat, err := os.Stat(hostPath)
if err != nil {
return "", errors.Wrapf(err, "error statting %q for container %q", hostPath, b.ContainerID)
}
contents, err := ioutil.ReadFile(hostPath)
if err != nil {
return "", errors.Wrapf(err, "unable to read %s", hostPath)
}
search := resolvconf.GetSearchDomains(contents)
nameservers := resolvconf.GetNameservers(contents, types.IP)
options := resolvconf.GetOptions(contents)
defaultContainerConfig, err := config.Default()
if err != nil {
return "", errors.Wrapf(err, "failed to get container config")
}
dnsSearch = append(defaultContainerConfig.Containers.DNSSearches, dnsSearch...)
if len(dnsSearch) > 0 {
search = dnsSearch
}
if b.Isolation == IsolationOCIRootless {
ns := namespaceOptions.Find(string(specs.NetworkNamespace))
if ns != nil && !ns.Host && ns.Path == "" {
// if we are using slirp4netns, also add the built-in DNS server.
logrus.Debugf("adding slirp4netns 10.0.2.3 built-in DNS server")
nameservers = append([]string{"10.0.2.3"}, nameservers...)
}
}
dnsServers = append(defaultContainerConfig.Containers.DNSServers, dnsServers...)
if len(dnsServers) != 0 {
dns, err := getDNSIP(dnsServers)
if err != nil {
return "", errors.Wrapf(err, "error getting dns servers")
}
nameservers = []string{}
for _, server := range dns {
nameservers = append(nameservers, server.String())
}
}
dnsOptions = append(defaultContainerConfig.Containers.DNSOptions, dnsOptions...)
if len(dnsOptions) != 0 {
options = dnsOptions
}
cfile := filepath.Join(rdir, filepath.Base(hostPath))
if _, err = resolvconf.Build(cfile, nameservers, search, options); err != nil {
return "", errors.Wrapf(err, "error building resolv.conf for container %s", b.ContainerID)
}
uid := int(stat.Sys().(*syscall.Stat_t).Uid)
gid := int(stat.Sys().(*syscall.Stat_t).Gid)
if chownOpts != nil {
uid = chownOpts.UID
gid = chownOpts.GID
}
if err = os.Chown(cfile, uid, gid); err != nil {
return "", errors.Wrapf(err, "error chowning file %q for container %q", cfile, b.ContainerID)
}
if err := label.Relabel(cfile, b.MountLabel, false); err != nil {
return "", errors.Wrapf(err, "error relabeling %q in container %q", cfile, b.ContainerID)
}
return cfile, nil
}
// generateHosts creates a containers hosts file
func (b *Builder) generateHosts(rdir, hostname string, addHosts []string, chownOpts *idtools.IDPair) (string, error) {
hostPath := "/etc/hosts"
stat, err := os.Stat(hostPath)
if err != nil {
return "", errors.Wrapf(err, "error statting %q for container %q", hostPath, b.ContainerID)
}
hosts := bytes.NewBufferString("# Generated by Buildah\n")
orig, err := ioutil.ReadFile(hostPath)
if err != nil {
return "", errors.Wrapf(err, "unable to read %s", hostPath)
}
hosts.Write(orig)
for _, host := range addHosts {
// verify the host format
values := strings.SplitN(host, ":", 2)
if len(values) != 2 {
return "", errors.Errorf("unable to parse host entry %q: incorrect format", host)
}
if values[0] == "" {
return "", errors.Errorf("hostname in host entry %q is empty", host)
}
if values[1] == "" {
return "", errors.Errorf("IP address in host entry %q is empty", host)
}
hosts.Write([]byte(fmt.Sprintf("%s\t%s\n", values[1], values[0])))
}
if hostname != "" {
hosts.Write([]byte(fmt.Sprintf("127.0.0.1 %s\n", hostname)))
hosts.Write([]byte(fmt.Sprintf("::1 %s\n", hostname)))
}
cfile := filepath.Join(rdir, filepath.Base(hostPath))
if err = ioutils.AtomicWriteFile(cfile, hosts.Bytes(), stat.Mode().Perm()); err != nil {
return "", errors.Wrapf(err, "error writing /etc/hosts into the container")
}
uid := int(stat.Sys().(*syscall.Stat_t).Uid)
gid := int(stat.Sys().(*syscall.Stat_t).Gid)
if chownOpts != nil {
uid = chownOpts.UID
gid = chownOpts.GID
}
if err = os.Chown(cfile, uid, gid); err != nil {
return "", errors.Wrapf(err, "error chowning file %q for container %q", cfile, b.ContainerID)
}
if err := label.Relabel(cfile, b.MountLabel, false); err != nil {
return "", errors.Wrapf(err, "error relabeling %q in container %q", cfile, b.ContainerID)
}
return cfile, nil
}
func setupTerminal(g *generate.Generator, terminalPolicy TerminalPolicy, terminalSize *specs.Box) {
switch terminalPolicy {
case DefaultTerminal:
onTerminal := terminal.IsTerminal(unix.Stdin) && terminal.IsTerminal(unix.Stdout) && terminal.IsTerminal(unix.Stderr)
if onTerminal {
logrus.Debugf("stdio is a terminal, defaulting to using a terminal")
} else {
logrus.Debugf("stdio is not a terminal, defaulting to not using a terminal")
}
g.SetProcessTerminal(onTerminal)
case WithTerminal:
g.SetProcessTerminal(true)
case WithoutTerminal:
g.SetProcessTerminal(false)
}
if terminalSize != nil {
g.SetProcessConsoleSize(terminalSize.Width, terminalSize.Height)
}
}
func runUsingRuntime(isolation Isolation, options RunOptions, configureNetwork bool, configureNetworks, moreCreateArgs []string, spec *specs.Spec, bundlePath, containerName string) (wstatus unix.WaitStatus, err error) {
// Lock the caller to a single OS-level thread.
runtime.LockOSThread()
// Set up bind mounts for things that a namespaced user might not be able to get to directly.
unmountAll, err := bind.SetupIntermediateMountNamespace(spec, bundlePath)
if unmountAll != nil {
defer func() {
if err := unmountAll(); err != nil {
logrus.Error(err)
}
}()
}
if err != nil {
return 1, err
}
// Write the runtime configuration.
specbytes, err := json.Marshal(spec)
if err != nil {
return 1, errors.Wrapf(err, "error encoding configuration %#v as json", spec)
}
if err = ioutils.AtomicWriteFile(filepath.Join(bundlePath, "config.json"), specbytes, 0600); err != nil {
return 1, errors.Wrapf(err, "error storing runtime configuration in %q", filepath.Join(bundlePath, "config.json"))
}
logrus.Debugf("config = %v", string(specbytes))
// Decide which runtime to use.
runtime := options.Runtime
if runtime == "" {
runtime = util.Runtime()
localRuntime := util.FindLocalRuntime(runtime)
if localRuntime != "" {
runtime = localRuntime
}
}
// Default to just passing down our stdio.
getCreateStdio := func() (io.ReadCloser, io.WriteCloser, io.WriteCloser) {
return os.Stdin, os.Stdout, os.Stderr
}
// Figure out how we're doing stdio handling, and create pipes and sockets.
var stdio sync.WaitGroup
var consoleListener *net.UnixListener
var errorFds, closeBeforeReadingErrorFds []int
stdioPipe := make([][]int, 3)
copyConsole := false
copyPipes := false
finishCopy := make([]int, 2)
if err = unix.Pipe(finishCopy); err != nil {
return 1, errors.Wrapf(err, "error creating pipe for notifying to stop stdio")
}
finishedCopy := make(chan struct{})
var pargs []string
if spec.Process != nil {
pargs = spec.Process.Args
if spec.Process.Terminal {
copyConsole = true
// Create a listening socket for accepting the container's terminal's PTY master.
socketPath := filepath.Join(bundlePath, "console.sock")
consoleListener, err = net.ListenUnix("unix", &net.UnixAddr{Name: socketPath, Net: "unix"})
if err != nil {
return 1, errors.Wrapf(err, "error creating socket %q to receive terminal descriptor", consoleListener.Addr())
}
// Add console socket arguments.
moreCreateArgs = append(moreCreateArgs, "--console-socket", socketPath)
} else {
copyPipes = true
// Figure out who should own the pipes.
uid, gid, err := util.GetHostRootIDs(spec)
if err != nil {
return 1, err
}
// Create stdio pipes.
if stdioPipe, err = runMakeStdioPipe(int(uid), int(gid)); err != nil {
return 1, err
}
errorFds = []int{stdioPipe[unix.Stdout][0], stdioPipe[unix.Stderr][0]}
closeBeforeReadingErrorFds = []int{stdioPipe[unix.Stdout][1], stdioPipe[unix.Stderr][1]}
// Set stdio to our pipes.
getCreateStdio = func() (io.ReadCloser, io.WriteCloser, io.WriteCloser) {
stdin := os.NewFile(uintptr(stdioPipe[unix.Stdin][0]), "/dev/stdin")
stdout := os.NewFile(uintptr(stdioPipe[unix.Stdout][1]), "/dev/stdout")
stderr := os.NewFile(uintptr(stdioPipe[unix.Stderr][1]), "/dev/stderr")
return stdin, stdout, stderr
}
}
} else {
if options.Quiet {
// Discard stdout.
getCreateStdio = func() (io.ReadCloser, io.WriteCloser, io.WriteCloser) {
return os.Stdin, nil, os.Stderr
}
}
}
// Build the commands that we'll execute.
pidFile := filepath.Join(bundlePath, "pid")
args := append(append(append(options.Args, "create", "--bundle", bundlePath, "--pid-file", pidFile), moreCreateArgs...), containerName)
create := exec.Command(runtime, args...)
create.Dir = bundlePath
stdin, stdout, stderr := getCreateStdio()
create.Stdin, create.Stdout, create.Stderr = stdin, stdout, stderr
if create.SysProcAttr == nil {
create.SysProcAttr = &syscall.SysProcAttr{}
}
args = append(options.Args, "start", containerName)
start := exec.Command(runtime, args...)
start.Dir = bundlePath
start.Stderr = os.Stderr
args = append(options.Args, "kill", containerName)
kill := exec.Command(runtime, args...)
kill.Dir = bundlePath
kill.Stderr = os.Stderr
args = append(options.Args, "delete", containerName)
del := exec.Command(runtime, args...)
del.Dir = bundlePath
del.Stderr = os.Stderr
// Actually create the container.
logrus.Debugf("Running %q", create.Args)
err = create.Run()
if err != nil {
return 1, errors.Wrapf(err, "error creating container for %v: %s", pargs, runCollectOutput(errorFds, closeBeforeReadingErrorFds))
}
defer func() {
err2 := del.Run()
if err2 != nil {
if err == nil {
err = errors.Wrapf(err2, "error deleting container")
} else {
logrus.Infof("error deleting container: %v", err2)
}
}
}()
// Make sure we read the container's exit status when it exits.
pidValue, err := ioutil.ReadFile(pidFile)
if err != nil {
return 1, errors.Wrapf(err, "error reading pid from %q", pidFile)
}
pid, err := strconv.Atoi(strings.TrimSpace(string(pidValue)))
if err != nil {
return 1, errors.Wrapf(err, "error parsing pid %s as a number", string(pidValue))
}
var reaping sync.WaitGroup
reaping.Add(1)
go func() {
defer reaping.Done()
var err error
_, err = unix.Wait4(pid, &wstatus, 0, nil)
if err != nil {
wstatus = 0
logrus.Errorf("error waiting for container child process %d: %v\n", pid, err)
}
}()
if configureNetwork {
teardown, err := runConfigureNetwork(isolation, options, configureNetworks, pid, containerName, pargs)
if teardown != nil {
defer teardown()
}
if err != nil {
return 1, err
}
}
if copyPipes {
// We don't need the ends of the pipes that belong to the container.
stdin.Close()
if stdout != nil {
stdout.Close()
}
stderr.Close()
}
// Handle stdio for the container in the background.
stdio.Add(1)
go runCopyStdio(&stdio, copyPipes, stdioPipe, copyConsole, consoleListener, finishCopy, finishedCopy, spec)
// Start the container.
logrus.Debugf("Running %q", start.Args)
err = start.Run()
if err != nil {
return 1, errors.Wrapf(err, "error starting container")
}
stopped := false
defer func() {
if !stopped {
if err2 := kill.Run(); err2 != nil {
logrus.Infof("error stopping container: %v", err2)
}
}
}()
// Wait for the container to exit.
for {
now := time.Now()
var state specs.State
args = append(options.Args, "state", containerName)
stat := exec.Command(runtime, args...)
stat.Dir = bundlePath
stat.Stderr = os.Stderr
stateOutput, stateErr := stat.Output()
if stateErr != nil {
return 1, errors.Wrapf(stateErr, "error reading container state")
}
if err = json.Unmarshal(stateOutput, &state); err != nil {
return 1, errors.Wrapf(stateErr, "error parsing container state %q", string(stateOutput))
}
switch state.Status {
case "running":
case "stopped":
stopped = true
default:
return 1, errors.Errorf("container status unexpectedly changed to %q", state.Status)
}
if stopped {
break
}
select {
case <-finishedCopy:
stopped = true
case <-time.After(time.Until(now.Add(100 * time.Millisecond))):
continue
}
if stopped {
break
}
}
// Close the writing end of the stop-handling-stdio notification pipe.
unix.Close(finishCopy[1])
// Wait for the stdio copy goroutine to flush.
stdio.Wait()
// Wait until we finish reading the exit status.
reaping.Wait()
return wstatus, nil
}
func runCollectOutput(fds, closeBeforeReadingFds []int) string {
for _, fd := range closeBeforeReadingFds {
unix.Close(fd)
}
var b bytes.Buffer
buf := make([]byte, 8192)
for _, fd := range fds {
nread, err := unix.Read(fd, buf)
if err != nil {
if errno, isErrno := err.(syscall.Errno); isErrno {
switch errno {
default:
logrus.Errorf("error reading from pipe %d: %v", fd, err)
case syscall.EINTR, syscall.EAGAIN:
}
} else {
logrus.Errorf("unable to wait for data from pipe %d: %v", fd, err)
}
continue
}
for nread > 0 {
r := buf[:nread]
if nwritten, err := b.Write(r); err != nil || nwritten != len(r) {
if nwritten != len(r) {
logrus.Errorf("error buffering data from pipe %d: %v", fd, err)
break
}
}
nread, err = unix.Read(fd, buf)
if err != nil {
if errno, isErrno := err.(syscall.Errno); isErrno {
switch errno {
default:
logrus.Errorf("error reading from pipe %d: %v", fd, err)
case syscall.EINTR, syscall.EAGAIN:
}
} else {
logrus.Errorf("unable to wait for data from pipe %d: %v", fd, err)
}
break
}
}
}
return b.String()
}
func setupRootlessNetwork(pid int) (teardown func(), err error) {
slirp4netns, err := exec.LookPath("slirp4netns")
if err != nil {
return nil, errors.Wrapf(err, "cannot find slirp4netns")
}
rootlessSlirpSyncR, rootlessSlirpSyncW, err := os.Pipe()
if err != nil {
return nil, errors.Wrapf(err, "cannot create slirp4netns sync pipe")
}
defer rootlessSlirpSyncR.Close()
// Be sure there are no fds inherited to slirp4netns except the sync pipe
files, err := ioutil.ReadDir("/proc/self/fd")
if err != nil {
return nil, errors.Wrapf(err, "cannot list open fds")
}
for _, f := range files {
fd, err := strconv.Atoi(f.Name())
if err != nil {
return nil, errors.Wrapf(err, "cannot parse fd")
}
if fd == int(rootlessSlirpSyncW.Fd()) {
continue
}
unix.CloseOnExec(fd)
}
cmd := exec.Command(slirp4netns, "--mtu", "65520", "-r", "3", "-c", fmt.Sprintf("%d", pid), "tap0")
cmd.Stdin, cmd.Stdout, cmd.Stderr = nil, nil, nil
cmd.ExtraFiles = []*os.File{rootlessSlirpSyncW}
err = cmd.Start()
rootlessSlirpSyncW.Close()
if err != nil {
return nil, errors.Wrapf(err, "cannot start slirp4netns")
}
b := make([]byte, 1)
for {
if err := rootlessSlirpSyncR.SetDeadline(time.Now().Add(1 * time.Second)); err != nil {
return nil, errors.Wrapf(err, "error setting slirp4netns pipe timeout")
}
if _, err := rootlessSlirpSyncR.Read(b); err == nil {
break
} else {
if os.IsTimeout(err) {
// Check if the process is still running.
var status syscall.WaitStatus
_, err := syscall.Wait4(cmd.Process.Pid, &status, syscall.WNOHANG, nil)