package libpod import ( "bytes" "encoding/json" "fmt" "io/ioutil" "os" "os/exec" "path/filepath" "runtime" "strconv" "strings" "sync" "syscall" "time" "github.com/containerd/cgroups" "github.com/containers/storage/pkg/idtools" "github.com/coreos/go-systemd/activation" spec "github.com/opencontainers/runtime-spec/specs-go" selinux "github.com/opencontainers/selinux/go-selinux" "github.com/opencontainers/selinux/go-selinux/label" "github.com/pkg/errors" "github.com/sirupsen/logrus" "golang.org/x/sys/unix" kwait "k8s.io/apimachinery/pkg/util/wait" // TODO import these functions into libpod and remove the import // Trying to keep libpod from depending on CRI-O code "github.com/projectatomic/libpod/utils" ) // OCI code is undergoing heavy rewrite const ( // CgroupfsCgroupsManager represents cgroupfs native cgroup manager CgroupfsCgroupsManager = "cgroupfs" // SystemdCgroupsManager represents systemd native cgroup manager SystemdCgroupsManager = "systemd" // ContainerCreateTimeout represents the value of container creating timeout ContainerCreateTimeout = 240 * time.Second // Timeout before declaring that runtime has failed to kill a given // container killContainerTimeout = 5 * time.Second // DefaultShmSize is the default shm size DefaultShmSize = 64 * 1024 * 1024 // NsRunDir is the default directory in which running network namespaces // are stored NsRunDir = "/var/run/netns" ) // OCIRuntime represents an OCI-compatible runtime that libpod can call into // to perform container operations type OCIRuntime struct { name string path string conmonPath string conmonEnv []string cgroupManager string tmpDir string exitsDir string socketsDir string logSizeMax int64 noPivot bool } // syncInfo is used to return data from monitor process to daemon type syncInfo struct { Pid int `json:"pid"` Message string `json:"message,omitempty"` } // Make a new OCI runtime with provided options func newOCIRuntime(name string, path string, conmonPath string, conmonEnv []string, cgroupManager string, tmpDir string, logSizeMax int64, noPivotRoot bool) (*OCIRuntime, error) { runtime := new(OCIRuntime) runtime.name = name runtime.path = path runtime.conmonPath = conmonPath runtime.conmonEnv = conmonEnv runtime.cgroupManager = cgroupManager runtime.tmpDir = tmpDir runtime.logSizeMax = logSizeMax runtime.noPivot = noPivotRoot runtime.exitsDir = filepath.Join(runtime.tmpDir, "exits") runtime.socketsDir = filepath.Join(runtime.tmpDir, "socket") if cgroupManager != CgroupfsCgroupsManager && cgroupManager != SystemdCgroupsManager { return nil, errors.Wrapf(ErrInvalidArg, "invalid cgroup manager specified: %s", cgroupManager) } // Create the exit files and attach sockets directories if err := os.MkdirAll(runtime.exitsDir, 0750); err != nil { // The directory is allowed to exist if !os.IsExist(err) { return nil, errors.Wrapf(err, "error creating OCI runtime exit files directory %s", runtime.exitsDir) } } if err := os.MkdirAll(runtime.socketsDir, 0750); err != nil { // The directory is allowed to exist if !os.IsExist(err) { return nil, errors.Wrapf(err, "error creating OCI runtime attach sockets directory %s", runtime.socketsDir) } } return runtime, nil } // newPipe creates a unix socket pair for communication func newPipe() (parent *os.File, child *os.File, err error) { fds, err := unix.Socketpair(unix.AF_LOCAL, unix.SOCK_STREAM|unix.SOCK_CLOEXEC, 0) if err != nil { return nil, nil, err } return os.NewFile(uintptr(fds[1]), "parent"), os.NewFile(uintptr(fds[0]), "child"), nil } // Create systemd unit name for cgroup scopes func createUnitName(prefix string, name string) string { return fmt.Sprintf("%s-%s.scope", prefix, name) } // Wait for a container which has been sent a signal to stop func waitContainerStop(ctr *Container, timeout time.Duration) error { done := make(chan struct{}) chControl := make(chan struct{}) go func() { for { select { case <-chControl: return default: // Check if the process is still around err := unix.Kill(ctr.state.PID, 0) if err == unix.ESRCH { close(done) return } time.Sleep(100 * time.Millisecond) } } }() select { case <-done: return nil case <-time.After(timeout): close(chControl) return errors.Errorf("container %s did not die within timeout", ctr.ID()) } } // Wait for a set of given PIDs to stop func waitPidsStop(pids []int, timeout time.Duration) error { done := make(chan struct{}) chControl := make(chan struct{}) go func() { for { select { case <-chControl: return default: allClosed := true for _, pid := range pids { if err := unix.Kill(pid, 0); err != unix.ESRCH { allClosed = false break } } if allClosed { close(done) return } time.Sleep(100 * time.Millisecond) } } }() select { case <-done: return nil case <-time.After(timeout): close(chControl) return errors.Errorf("given PIDs did not die within timeout") } } // CreateContainer creates a container in the OCI runtime // TODO terminal support for container // Presently just ignoring conmon opts related to it func (r *OCIRuntime) createContainer(ctr *Container, cgroupParent string) (err error) { if ctr.state.UserNSRoot == "" { // no need of an intermediate mount ns return r.createOCIContainer(ctr, cgroupParent) } var wg sync.WaitGroup wg.Add(1) go func() { defer wg.Done() runtime.LockOSThread() fd, err := os.Open(fmt.Sprintf("/proc/%d/task/%d/ns/mnt", os.Getpid(), unix.Gettid())) if err != nil { return } defer fd.Close() // create a new mountns on the current thread if err = unix.Unshare(unix.CLONE_NEWNS); err != nil { return } defer unix.Setns(int(fd.Fd()), unix.CLONE_NEWNS) // don't spread our mounts around err = unix.Mount("/", "/", "none", unix.MS_REC|unix.MS_SLAVE, "") if err != nil { return } err = unix.Mount(ctr.state.Mountpoint, ctr.state.RealMountpoint, "none", unix.MS_BIND, "") if err != nil { return } if err := idtools.MkdirAllAs(ctr.state.DestinationRunDir, 0700, ctr.RootUID(), ctr.RootGID()); err != nil { return } err = unix.Mount(ctr.state.RunDir, ctr.state.DestinationRunDir, "none", unix.MS_BIND, "") if err != nil { return } err = r.createOCIContainer(ctr, cgroupParent) }() wg.Wait() return err } func (r *OCIRuntime) createOCIContainer(ctr *Container, cgroupParent string) (err error) { var stderrBuf bytes.Buffer parentPipe, childPipe, err := newPipe() if err != nil { return errors.Wrapf(err, "error creating socket pair") } childStartPipe, parentStartPipe, err := newPipe() if err != nil { return errors.Wrapf(err, "error creating socket pair for start pipe") } defer parentPipe.Close() defer parentStartPipe.Close() args := []string{} if r.cgroupManager == SystemdCgroupsManager { args = append(args, "-s") } args = append(args, "-c", ctr.ID()) args = append(args, "-u", ctr.ID()) args = append(args, "-r", r.path) args = append(args, "-b", ctr.bundlePath()) args = append(args, "-p", filepath.Join(ctr.state.RunDir, "pidfile")) args = append(args, "-l", ctr.LogPath()) args = append(args, "--exit-dir", r.exitsDir) if ctr.config.ConmonPidFile != "" { args = append(args, "--conmon-pidfile", ctr.config.ConmonPidFile) } args = append(args, "--socket-dir-path", r.socketsDir) if ctr.config.Spec.Process.Terminal { args = append(args, "-t") } else if ctr.config.Stdin { args = append(args, "-i") } if r.logSizeMax >= 0 { args = append(args, "--log-size-max", fmt.Sprintf("%v", r.logSizeMax)) } if r.noPivot { args = append(args, "--no-pivot") } if logrus.GetLevel() == logrus.DebugLevel { logrus.Debug("%s messages will be logged to syslog", r.conmonPath) args = append(args, "--syslog") } logrus.WithFields(logrus.Fields{ "args": args, }).Debugf("running conmon: %s", r.conmonPath) cmd := exec.Command(r.conmonPath, args...) cmd.Dir = ctr.bundlePath() cmd.SysProcAttr = &syscall.SysProcAttr{ Setpgid: true, } // TODO this is probably a really bad idea for some uses // Make this configurable cmd.Stdin = os.Stdin cmd.Stdout = os.Stdout cmd.Stderr = os.Stderr if ctr.config.Spec.Process.Terminal { cmd.Stderr = &stderrBuf } cmd.ExtraFiles = append(cmd.ExtraFiles, childPipe, childStartPipe) // 0, 1 and 2 are stdin, stdout and stderr cmd.Env = append(r.conmonEnv, fmt.Sprintf("_OCI_SYNCPIPE=%d", 3)) cmd.Env = append(cmd.Env, fmt.Sprintf("_OCI_STARTPIPE=%d", 4)) cmd.Env = append(cmd.Env, fmt.Sprintf("XDG_RUNTIME_DIR=%s", GetRootlessRuntimeDir())) if notify, ok := os.LookupEnv("NOTIFY_SOCKET"); ok { cmd.Env = append(cmd.Env, fmt.Sprintf("NOTIFY_SOCKET=%s", notify)) } if listenfds, ok := os.LookupEnv("LISTEN_FDS"); ok { cmd.Env = append(cmd.Env, fmt.Sprintf("LISTEN_FDS=%s", listenfds), "LISTEN_PID=1") fds := activation.Files(false) cmd.ExtraFiles = append(cmd.ExtraFiles, fds...) } if selinux.GetEnabled() { // Set the label of the conmon process to be level :s0 // This will allow the container processes to talk to fifo-files // passed into the container by conmon plabel, err := selinux.CurrentLabel() if err != nil { childPipe.Close() return errors.Wrapf(err, "Failed to get current SELinux label") } c := selinux.NewContext(plabel) runtime.LockOSThread() if c["level"] != "s0" && c["level"] != "" { c["level"] = "s0" if err := label.SetProcessLabel(c.Get()); err != nil { runtime.UnlockOSThread() return err } } err = cmd.Start() // Ignore error returned from SetProcessLabel("") call, // can't recover. label.SetProcessLabel("") runtime.UnlockOSThread() } else { err = cmd.Start() } if err != nil { childPipe.Close() return err } // We don't need childPipe on the parent side childPipe.Close() childStartPipe.Close() // Move conmon to specified cgroup if os.Getuid() == 0 { if r.cgroupManager == SystemdCgroupsManager { unitName := createUnitName("libpod-conmon", ctr.ID()) logrus.Infof("Running conmon under slice %s and unitName %s", cgroupParent, unitName) if err = utils.RunUnderSystemdScope(cmd.Process.Pid, cgroupParent, unitName); err != nil { logrus.Warnf("Failed to add conmon to systemd sandbox cgroup: %v", err) } } else { cgroupPath := filepath.Join(ctr.config.CgroupParent, fmt.Sprintf("libpod-%s", ctr.ID()), "conmon") control, err := cgroups.New(cgroups.V1, cgroups.StaticPath(cgroupPath), &spec.LinuxResources{}) if err != nil { logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err) } else { // we need to remove this defer and delete the cgroup once conmon exits // maybe need a conmon monitor? if err := control.Add(cgroups.Process{Pid: cmd.Process.Pid}); err != nil { logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err) } } } } /* We set the cgroup, now the child can start creating children */ someData := []byte{0} _, err = parentStartPipe.Write(someData) if err != nil { return err } /* Wait for initial setup and fork, and reap child */ err = cmd.Wait() if err != nil { return err } defer func() { if err != nil { if err2 := r.deleteContainer(ctr); err2 != nil { logrus.Errorf("Error removing container %s from runtime after creation failed", ctr.ID()) } } }() // Wait to get container pid from conmon type syncStruct struct { si *syncInfo err error } ch := make(chan syncStruct) go func() { var si *syncInfo if err = json.NewDecoder(parentPipe).Decode(&si); err != nil { ch <- syncStruct{err: err} return } ch <- syncStruct{si: si} }() select { case ss := <-ch: if ss.err != nil { return errors.Wrapf(ss.err, "error reading container (probably exited) json message") } logrus.Debugf("Received container pid: %d", ss.si.Pid) if ss.si.Pid == -1 { if ss.si.Message != "" { return errors.Wrapf(ErrInternal, "container create failed: %s", ss.si.Message) } return errors.Wrapf(ErrInternal, "container create failed") } case <-time.After(ContainerCreateTimeout): return errors.Wrapf(ErrInternal, "container creation timeout") } return nil } // updateContainerStatus retrieves the current status of the container from the // runtime. It updates the container's state but does not save it. func (r *OCIRuntime) updateContainerStatus(ctr *Container) error { state := new(spec.State) // Store old state so we know if we were already stopped oldState := ctr.state.State out, err := exec.Command(r.path, "state", ctr.ID()).CombinedOutput() if err != nil { if strings.Contains(string(out), "does not exist") { ctr.removeConmonFiles() ctr.state.State = ContainerStateConfigured return nil } return errors.Wrapf(err, "error getting container %s state. stderr/out: %s", ctr.ID(), out) } if err := json.NewDecoder(bytes.NewBuffer(out)).Decode(state); err != nil { return errors.Wrapf(err, "error decoding container status for container %s", ctr.ID()) } ctr.state.PID = state.Pid switch state.Status { case "created": ctr.state.State = ContainerStateCreated case "paused": ctr.state.State = ContainerStatePaused case "running": ctr.state.State = ContainerStateRunning case "stopped": ctr.state.State = ContainerStateStopped default: return errors.Wrapf(ErrInternal, "unrecognized status returned by runtime for container %s: %s", ctr.ID(), state.Status) } // Only grab exit status if we were not already stopped // If we were, it should already be in the database if ctr.state.State == ContainerStateStopped && oldState != ContainerStateStopped { exitFile := filepath.Join(r.exitsDir, ctr.ID()) var fi os.FileInfo err = kwait.ExponentialBackoff( kwait.Backoff{ Duration: 500 * time.Millisecond, Factor: 1.2, Steps: 6, }, func() (bool, error) { var err error fi, err = os.Stat(exitFile) if err != nil { // wait longer return false, nil } return true, nil }) if err != nil { ctr.state.ExitCode = -1 ctr.state.FinishedTime = time.Now() logrus.Errorf("No exit file for container %s found: %v", ctr.ID(), err) return nil } ctr.state.FinishedTime = getFinishedTime(fi) statusCodeStr, err := ioutil.ReadFile(exitFile) if err != nil { return errors.Wrapf(err, "failed to read exit file for container %s", ctr.ID()) } statusCode, err := strconv.Atoi(string(statusCodeStr)) if err != nil { return errors.Wrapf(err, "error converting exit status code for container %s to int", ctr.ID()) } ctr.state.ExitCode = int32(statusCode) oomFilePath := filepath.Join(ctr.bundlePath(), "oom") if _, err = os.Stat(oomFilePath); err == nil { ctr.state.OOMKilled = true } } return nil } // startContainer starts the given container // Sets time the container was started, but does not save it. func (r *OCIRuntime) startContainer(ctr *Container) error { // TODO: streams should probably *not* be our STDIN/OUT/ERR - redirect to buffers? if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "start", ctr.ID()); err != nil { return err } ctr.state.StartedTime = time.Now() return nil } // killContainer sends the given signal to the given container func (r *OCIRuntime) killContainer(ctr *Container, signal uint) error { logrus.Debugf("Sending signal %d to container %s", signal, ctr.ID()) if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "kill", ctr.ID(), fmt.Sprintf("%d", signal)); err != nil { return errors.Wrapf(err, "error sending signal to container %s", ctr.ID()) } return nil } // stopContainer stops a container, first using its given stop signal (or // SIGTERM if no signal was specified), then using SIGKILL // Timeout is given in seconds. If timeout is 0, the container will be // immediately kill with SIGKILL // Does not set finished time for container, assumes you will run updateStatus // after to pull the exit code func (r *OCIRuntime) stopContainer(ctr *Container, timeout uint) error { // Ping the container to see if it's alive // If it's not, it's already stopped, return err := unix.Kill(ctr.state.PID, 0) if err == unix.ESRCH { return nil } stopSignal := ctr.config.StopSignal if stopSignal == 0 { stopSignal = uint(syscall.SIGTERM) } if timeout > 0 { if err := r.killContainer(ctr, stopSignal); err != nil { // Is the container gone? // If so, it probably died between the first check and // our sending the signal // The container is stopped, so exit cleanly err := unix.Kill(ctr.state.PID, 0) if err == unix.ESRCH { return nil } return err } if err := waitContainerStop(ctr, time.Duration(timeout)*time.Second); err != nil { logrus.Warnf("Timed out stopping container %s, resorting to SIGKILL", ctr.ID()) } else { // No error, the container is dead return nil } } if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "kill", "--all", ctr.ID(), "KILL"); err != nil { // Again, check if the container is gone. If it is, exit cleanly. err := unix.Kill(ctr.state.PID, 0) if err == unix.ESRCH { return nil } return errors.Wrapf(err, "error sending SIGKILL to container %s", ctr.ID()) } // Give runtime a few seconds to make it happen if err := waitContainerStop(ctr, killContainerTimeout); err != nil { return err } return nil } // deleteContainer deletes a container from the OCI runtime func (r *OCIRuntime) deleteContainer(ctr *Container) error { _, err := utils.ExecCmd(r.path, "delete", "--force", ctr.ID()) return err } // pauseContainer pauses the given container func (r *OCIRuntime) pauseContainer(ctr *Container) error { return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "pause", ctr.ID()) } // unpauseContainer unpauses the given container func (r *OCIRuntime) unpauseContainer(ctr *Container) error { return utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "resume", ctr.ID()) } // execContainer executes a command in a running container // TODO: Add --detach support // TODO: Convert to use conmon // TODO: add --pid-file and use that to generate exec session tracking func (r *OCIRuntime) execContainer(c *Container, cmd, capAdd, env []string, tty bool, user, sessionID string) (*exec.Cmd, error) { if len(cmd) == 0 { return nil, errors.Wrapf(ErrInvalidArg, "must provide a command to execute") } if sessionID == "" { return nil, errors.Wrapf(ErrEmptyID, "must provide a session ID for exec") } args := []string{} // TODO - should we maintain separate logpaths for exec sessions? args = append(args, "--log", c.LogPath()) args = append(args, "exec") args = append(args, "--cwd", c.config.Spec.Process.Cwd) args = append(args, "--pid-file", c.execPidPath(sessionID)) if tty { args = append(args, "--tty") } if user != "" { args = append(args, "--user", user) } if c.config.Spec.Process.NoNewPrivileges { args = append(args, "--no-new-privs") } for _, cap := range capAdd { args = append(args, "--cap", cap) } for _, envVar := range env { args = append(args, "--env", envVar) } // Append container ID and command args = append(args, c.ID()) args = append(args, cmd...) logrus.Debugf("Starting runtime %s with following arguments: %v", r.path, args) execCmd := exec.Command(r.path, args...) execCmd.Stdout = os.Stdout execCmd.Stderr = os.Stderr execCmd.Stdin = os.Stdin return execCmd, nil } // execStopContainer stops all active exec sessions in a container // It will also stop all other processes in the container. It is only intended // to be used to assist in cleanup when removing a container. // SIGTERM is used by default to stop processes. If SIGTERM fails, SIGKILL will be used. func (r *OCIRuntime) execStopContainer(ctr *Container, timeout uint) error { // Do we have active exec sessions? if len(ctr.state.ExecSessions) == 0 { return nil } // Get a list of active exec sessions execSessions := []int{} for _, session := range ctr.state.ExecSessions { pid := session.PID // Ping the PID with signal 0 to see if it still exists if err := unix.Kill(pid, 0); err == unix.ESRCH { continue } execSessions = append(execSessions, pid) } // All the sessions may be dead // If they are, just return if len(execSessions) == 0 { return nil } // If timeout is 0, just use SIGKILL if timeout > 0 { // Stop using SIGTERM by default // Use SIGSTOP after a timeout logrus.Debugf("Killing all processes in container %s with SIGTERM", ctr.ID()) if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "kill", "--all", ctr.ID(), "TERM"); err != nil { return errors.Wrapf(err, "error sending SIGTERM to container %s processes", ctr.ID()) } // Wait for all processes to stop if err := waitPidsStop(execSessions, time.Duration(timeout)*time.Second); err != nil { logrus.Warnf("Timed out stopping container %s exec sessions", ctr.ID()) } else { // No error, all exec sessions are dead return nil } } // Send SIGKILL logrus.Debugf("Killing all processes in container %s with SIGKILL", ctr.ID()) if err := utils.ExecCmdWithStdStreams(os.Stdin, os.Stdout, os.Stderr, r.path, "kill", "--all", ctr.ID(), "KILL"); err != nil { return errors.Wrapf(err, "error sending SIGKILL to container %s processes", ctr.ID()) } // Give the processes a few seconds to go down if err := waitPidsStop(execSessions, killContainerTimeout); err != nil { return errors.Wrapf(err, "failed to kill container %s exec sessions", ctr.ID()) } return nil }