// 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. 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 networkState, err := syncPipe.ReadFromParent() if err != nil { return err } if consolePath != "" { if err := console.OpenAndDup(consolePath); err != nil { return err } } if _, err := system.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, (*mount.MountConfig)(container.MountConfig)); err != nil { return fmt.Errorf("setup mount namespace %s", err) } if container.Hostname != "" { if err := system.Sethostname(container.Hostname); err != nil { return fmt.Errorf("sethostname %s", err) } } runtime.LockOSThread() 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", "sys"); 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:], container.Env) }
// 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. func Init(container *libcontainer.Container, uncleanRootfs, consolePath string, syncPipe *SyncPipe, args []string) error { 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 context, err := syncPipe.ReadFromParent() if err != nil { syncPipe.Close() return err } syncPipe.Close() if consolePath != "" { if err := console.OpenAndDup(consolePath); err != nil { return err } } if _, err := system.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, context); 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); err != nil { return fmt.Errorf("setup mount namespace %s", err) } if container.Hostname != "" { if err := system.Sethostname(container.Hostname); err != nil { return fmt.Errorf("sethostname %s", err) } } runtime.LockOSThread() if err := apparmor.ApplyProfile(container.Context["apparmor_profile"]); err != nil { return fmt.Errorf("set apparmor profile %s: %s", container.Context["apparmor_profile"], err) } if err := label.SetProcessLabel(container.Context["process_label"]); err != nil { return fmt.Errorf("set process label %s", err) } if container.Context["restrictions"] != "" { if err := restrict.Restrict("proc/sys", "proc/sysrq-trigger", "proc/irq", "proc/bus", "sys"); 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:], container.Env) }