package libpod import ( "bytes" "encoding/json" "fmt" "io/ioutil" "os" "os/exec" "path/filepath" "strconv" "syscall" "time" "github.com/containerd/cgroups" spec "github.com/opencontainers/runtime-spec/specs-go" "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 runc 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()) } } // 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) { 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) 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") } 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)) 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 r.cgroupManager == SystemdCgroupsManager { logrus.Infof("Running conmon under slice %s and unitName %s", cgroupParent, createUnitName("libpod-conmon", ctr.ID())) if err = utils.RunUnderSystemdScope(cmd.Process.Pid, cgroupParent, createUnitName("libpod-conmon", ctr.ID())); err != nil { logrus.Warnf("Failed to add conmon to systemd sandbox cgroup: %v", err) } } else { control, err := cgroups.New(cgroups.V1, cgroups.StaticPath(filepath.Join(cgroupParent, "/libpod-conmon-"+ctr.ID())), &spec.LinuxResources{}) if err != nil { logrus.Warnf("Failed to add conmon to cgroupfs sandbox cgroup: %v", err) } else { // XXX: this defer does nothing as the cgroup can't be deleted cause // it contains the conmon pid in tasks // we need to remove this defer and delete the cgroup once conmon exits // maybe need a conmon monitor? defer control.Delete() 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 runc 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) out, err := exec.Command(r.path, "state", ctr.ID()).CombinedOutput() if err != 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 runc for container %s: %s", ctr.ID(), state.Status) } if ctr.state.State == 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() return errors.Wrapf(err, "no exit file for container %s found", ctr.ID()) } 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 convertaing 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 { 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 int64) 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 { 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 { return errors.Wrapf(err, "error sending SIGKILL to container %s", ctr.ID()) } // Give runc a few seconds to make it happen if err := waitContainerStop(ctr, killContainerTimeout); err != nil { return err } return nil } // deleteContainer deletes a container from runc 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()) }