// RestoreParentDeathSignal sets the parent death signal to old.
func RestoreParentDeathSignal(old int) error {
if old == 0 {
return nil
}
current, err := system.GetParentDeathSignal()
if err != nil {
return fmt.Errorf("get parent death signal %s", err)
}
if old == current {
return nil
}
if err := system.ParentDeathSignal(uintptr(old)); err != nil {
return fmt.Errorf("set parent death signal %s", err)
}
// Signal self if parent is already dead. Does nothing if running in a new
// PID namespace, as Getppid will always return 0.
if syscall.Getppid() == 1 {
return syscall.Kill(syscall.Getpid(), syscall.SIGKILL)
}
return nil
}
// TODO(vishh): This is part of the libcontainer API and it does much more than just namespaces related work.
// Move this to libcontainer package.
// Init is the init process that first runs inside a new namespace to setup mounts, users, networking,
// and other options required for the new container.
// The caller of Init function has to ensure that the go runtime is locked to an OS thread
// (using runtime.LockOSThread) else system calls like setns called within Init may not work as intended.
func Init(container *libcontainer.Config, uncleanRootfs, consolePath string, syncPipe *syncpipe.SyncPipe, args []string) (err error) {
defer func() {
if err != nil {
syncPipe.ReportChildError(err)
}
}()
rootfs, err := utils.ResolveRootfs(uncleanRootfs)
if err != nil {
return err
}
// clear the current processes env and replace it with the environment
// defined on the container
if err := LoadContainerEnvironment(container); err != nil {
return err
}
// We always read this as it is a way to sync with the parent as well
var networkState *network.NetworkState
if err := syncPipe.ReadFromParent(&networkState); err != nil {
return err
}
if consolePath != "" {
if err := console.OpenAndDup(consolePath); err != nil {
return err
}
}
if _, err := syscall.Setsid(); err != nil {
return fmt.Errorf("setsid %s", err)
}
if consolePath != "" {
if err := system.Setctty(); err != nil {
return fmt.Errorf("setctty %s", err)
}
}
if err := setupNetwork(container, networkState); err != nil {
return fmt.Errorf("setup networking %s", err)
}
if err := setupRoute(container); err != nil {
return fmt.Errorf("setup route %s", err)
}
label.Init()
if err := mount.InitializeMountNamespace(rootfs,
consolePath,
container.RestrictSys,
(*mount.MountConfig)(container.MountConfig)); err != nil {
return fmt.Errorf("setup mount namespace %s", err)
}
if container.Hostname != "" {
if err := syscall.Sethostname([]byte(container.Hostname)); err != nil {
return fmt.Errorf("sethostname %s", err)
}
}
if err := apparmor.ApplyProfile(container.AppArmorProfile); err != nil {
return fmt.Errorf("set apparmor profile %s: %s", container.AppArmorProfile, err)
}
if err := label.SetProcessLabel(container.ProcessLabel); err != nil {
return fmt.Errorf("set process label %s", err)
}
// TODO: (crosbymichael) make this configurable at the Config level
if container.RestrictSys {
if err := restrict.Restrict("proc/sys", "proc/sysrq-trigger", "proc/irq", "proc/bus"); err != nil {
return err
}
}
pdeathSignal, err := system.GetParentDeathSignal()
if err != nil {
return fmt.Errorf("get parent death signal %s", err)
}
if err := FinalizeNamespace(container); err != nil {
return fmt.Errorf("finalize namespace %s", err)
}
// FinalizeNamespace can change user/group which clears the parent death
// signal, so we restore it here.
if err := RestoreParentDeathSignal(pdeathSignal); err != nil {
return fmt.Errorf("restore parent death signal %s", err)
}
return system.Execv(args[0], args[0:], os.Environ())
}