package daemon import ( "bytes" "encoding/json" "errors" "fmt" "io" "io/ioutil" "os" "path" "path/filepath" "strings" "syscall" "time" "github.com/docker/libcontainer/devices" "github.com/docker/libcontainer/label" log "github.com/Sirupsen/logrus" "github.com/docker/docker/daemon/execdriver" "github.com/docker/docker/engine" "github.com/docker/docker/image" "github.com/docker/docker/links" "github.com/docker/docker/nat" "github.com/docker/docker/pkg/archive" "github.com/docker/docker/pkg/broadcastwriter" "github.com/docker/docker/pkg/ioutils" "github.com/docker/docker/pkg/networkfs/etchosts" "github.com/docker/docker/pkg/networkfs/resolvconf" "github.com/docker/docker/pkg/promise" "github.com/docker/docker/pkg/symlink" "github.com/docker/docker/runconfig" "github.com/docker/docker/utils" ) const DefaultPathEnv = "/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin" var ( ErrNotATTY = errors.New("The PTY is not a file") ErrNoTTY = errors.New("No PTY found") ErrContainerStart = errors.New("The container failed to start. Unknown error") ErrContainerStartTimeout = errors.New("The container failed to start due to timed out.") ) type StreamConfig struct { stdout *broadcastwriter.BroadcastWriter stderr *broadcastwriter.BroadcastWriter stdin io.ReadCloser stdinPipe io.WriteCloser } type Container struct { *State `json:"State"` // Needed for remote api version <= 1.11 root string // Path to the "home" of the container, including metadata. basefs string // Path to the graphdriver mountpoint ID string Created time.Time Path string Args []string Config *runconfig.Config ImageID string `json:"Image"` NetworkSettings *NetworkSettings ResolvConfPath string HostnamePath string HostsPath string Name string Driver string ExecDriver string command *execdriver.Command StreamConfig daemon *Daemon MountLabel, ProcessLabel string AppArmorProfile string RestartCount int UpdateDns bool // Maps container paths to volume paths. The key in this is the path to which // the volume is being mounted inside the container. Value is the path of the // volume on disk Volumes map[string]string // Store rw/ro in a separate structure to preserve reverse-compatibility on-disk. // Easier than migrating older container configs :) VolumesRW map[string]bool hostConfig *runconfig.HostConfig activeLinks map[string]*links.Link monitor *containerMonitor execCommands *execStore AppliedVolumesFrom map[string]struct{} } func (container *Container) FromDisk() error { pth, err := container.jsonPath() if err != nil { return err } jsonSource, err := os.Open(pth) if err != nil { return err } defer jsonSource.Close() dec := json.NewDecoder(jsonSource) // Load container settings // udp broke compat of docker.PortMapping, but it's not used when loading a container, we can skip it if err := dec.Decode(container); err != nil && !strings.Contains(err.Error(), "docker.PortMapping") { return err } if err := label.ReserveLabel(container.ProcessLabel); err != nil { return err } return container.readHostConfig() } func (container *Container) toDisk() error { data, err := json.Marshal(container) if err != nil { return err } pth, err := container.jsonPath() if err != nil { return err } err = ioutil.WriteFile(pth, data, 0666) if err != nil { return err } return container.WriteHostConfig() } func (container *Container) ToDisk() error { container.Lock() err := container.toDisk() container.Unlock() return err } func (container *Container) readHostConfig() error { container.hostConfig = &runconfig.HostConfig{} // If the hostconfig file does not exist, do not read it. // (We still have to initialize container.hostConfig, // but that's OK, since we just did that above.) pth, err := container.hostConfigPath() if err != nil { return err } _, err = os.Stat(pth) if os.IsNotExist(err) { return nil } data, err := ioutil.ReadFile(pth) if err != nil { return err } return json.Unmarshal(data, container.hostConfig) } func (container *Container) WriteHostConfig() error { data, err := json.Marshal(container.hostConfig) if err != nil { return err } pth, err := container.hostConfigPath() if err != nil { return err } return ioutil.WriteFile(pth, data, 0666) } func (container *Container) LogEvent(action string) { d := container.daemon if err := d.eng.Job("log", action, container.ID, d.Repositories().ImageName(container.ImageID)).Run(); err != nil { log.Errorf("Error logging event %s for %s: %s", action, container.ID, err) } } func (container *Container) getResourcePath(path string) (string, error) { cleanPath := filepath.Join("/", path) return symlink.FollowSymlinkInScope(filepath.Join(container.basefs, cleanPath), container.basefs) } func (container *Container) getRootResourcePath(path string) (string, error) { cleanPath := filepath.Join("/", path) return symlink.FollowSymlinkInScope(filepath.Join(container.root, cleanPath), container.root) } func populateCommand(c *Container, env []string) error { en := &execdriver.Network{ Mtu: c.daemon.config.Mtu, Interface: nil, } parts := strings.SplitN(string(c.hostConfig.NetworkMode), ":", 2) switch parts[0] { case "none": case "host": en.HostNetworking = true case "bridge", "": // empty string to support existing containers if !c.Config.NetworkDisabled { network := c.NetworkSettings en.Interface = &execdriver.NetworkInterface{ Gateway: network.Gateway, Bridge: network.Bridge, IPAddress: network.IPAddress, IPPrefixLen: network.IPPrefixLen, MacAddress: network.MacAddress, LinkLocalIPv6Address: network.LinkLocalIPv6Address, GlobalIPv6Address: network.GlobalIPv6Address, GlobalIPv6PrefixLen: network.GlobalIPv6PrefixLen, IPv6Gateway: network.IPv6Gateway, } } case "container": nc, err := c.getNetworkedContainer() if err != nil { return err } en.ContainerID = nc.ID default: return fmt.Errorf("invalid network mode: %s", c.hostConfig.NetworkMode) } ipc := &execdriver.Ipc{} if c.hostConfig.IpcMode.IsContainer() { ic, err := c.getIpcContainer() if err != nil { return err } ipc.ContainerID = ic.ID } else { ipc.HostIpc = c.hostConfig.IpcMode.IsHost() } pid := &execdriver.Pid{} pid.HostPid = c.hostConfig.PidMode.IsHost() // Build lists of devices allowed and created within the container. userSpecifiedDevices := make([]*devices.Device, len(c.hostConfig.Devices)) for i, deviceMapping := range c.hostConfig.Devices { device, err := devices.GetDevice(deviceMapping.PathOnHost, deviceMapping.CgroupPermissions) if err != nil { return fmt.Errorf("error gathering device information while adding custom device %q: %s", deviceMapping.PathOnHost, err) } device.Path = deviceMapping.PathInContainer userSpecifiedDevices[i] = device } allowedDevices := append(devices.DefaultAllowedDevices, userSpecifiedDevices...) autoCreatedDevices := append(devices.DefaultAutoCreatedDevices, userSpecifiedDevices...) // TODO: this can be removed after lxc-conf is fully deprecated lxcConfig, err := mergeLxcConfIntoOptions(c.hostConfig) if err != nil { return err } resources := &execdriver.Resources{ Memory: c.Config.Memory, MemorySwap: c.Config.MemorySwap, CpuShares: c.Config.CpuShares, Cpuset: c.Config.Cpuset, } processConfig := execdriver.ProcessConfig{ Privileged: c.hostConfig.Privileged, Entrypoint: c.Path, Arguments: c.Args, Tty: c.Config.Tty, User: c.Config.User, } processConfig.SysProcAttr = &syscall.SysProcAttr{Setsid: true} processConfig.Env = env c.command = &execdriver.Command{ ID: c.ID, Rootfs: c.RootfsPath(), ReadonlyRootfs: c.hostConfig.ReadonlyRootfs, InitPath: "/.dockerinit", WorkingDir: c.Config.WorkingDir, Network: en, Ipc: ipc, Pid: pid, Resources: resources, AllowedDevices: allowedDevices, AutoCreatedDevices: autoCreatedDevices, CapAdd: c.hostConfig.CapAdd, CapDrop: c.hostConfig.CapDrop, ProcessConfig: processConfig, ProcessLabel: c.GetProcessLabel(), MountLabel: c.GetMountLabel(), LxcConfig: lxcConfig, AppArmorProfile: c.AppArmorProfile, } return nil } func (container *Container) Start() (err error) { container.Lock() defer container.Unlock() if container.Running { return nil } // if we encounter and error during start we need to ensure that any other // setup has been cleaned up properly defer func() { if err != nil { container.setError(err) // if no one else has set it, make sure we don't leave it at zero if container.ExitCode == 0 { container.ExitCode = 128 } container.toDisk() container.cleanup() } }() if err := container.setupContainerDns(); err != nil { return err } if err := container.Mount(); err != nil { return err } if err := container.initializeNetworking(); err != nil { return err } if err := container.updateParentsHosts(); err != nil { return err } container.verifyDaemonSettings() if err := container.prepareVolumes(); err != nil { return err } linkedEnv, err := container.setupLinkedContainers() if err != nil { return err } if err := container.setupWorkingDirectory(); err != nil { return err } env := container.createDaemonEnvironment(linkedEnv) if err := populateCommand(container, env); err != nil { return err } if err := container.setupMounts(); err != nil { return err } return container.waitForStart() } func (container *Container) Run() error { if err := container.Start(); err != nil { return err } container.WaitStop(-1 * time.Second) return nil } func (container *Container) Output() (output []byte, err error) { pipe := container.StdoutPipe() defer pipe.Close() if err := container.Start(); err != nil { return nil, err } output, err = ioutil.ReadAll(pipe) container.WaitStop(-1 * time.Second) return output, err } // StreamConfig.StdinPipe returns a WriteCloser which can be used to feed data // to the standard input of the container's active process. // Container.StdoutPipe and Container.StderrPipe each return a ReadCloser // which can be used to retrieve the standard output (and error) generated // by the container's active process. The output (and error) are actually // copied and delivered to all StdoutPipe and StderrPipe consumers, using // a kind of "broadcaster". func (streamConfig *StreamConfig) StdinPipe() io.WriteCloser { return streamConfig.stdinPipe } func (streamConfig *StreamConfig) StdoutPipe() io.ReadCloser { reader, writer := io.Pipe() streamConfig.stdout.AddWriter(writer, "") return ioutils.NewBufReader(reader) } func (streamConfig *StreamConfig) StderrPipe() io.ReadCloser { reader, writer := io.Pipe() streamConfig.stderr.AddWriter(writer, "") return ioutils.NewBufReader(reader) } func (streamConfig *StreamConfig) StdoutLogPipe() io.ReadCloser { reader, writer := io.Pipe() streamConfig.stdout.AddWriter(writer, "stdout") return ioutils.NewBufReader(reader) } func (streamConfig *StreamConfig) StderrLogPipe() io.ReadCloser { reader, writer := io.Pipe() streamConfig.stderr.AddWriter(writer, "stderr") return ioutils.NewBufReader(reader) } func (container *Container) buildHostnameFile() error { hostnamePath, err := container.getRootResourcePath("hostname") if err != nil { return err } container.HostnamePath = hostnamePath if container.Config.Domainname != "" { return ioutil.WriteFile(container.HostnamePath, []byte(fmt.Sprintf("%s.%s\n", container.Config.Hostname, container.Config.Domainname)), 0644) } return ioutil.WriteFile(container.HostnamePath, []byte(container.Config.Hostname+"\n"), 0644) } func (container *Container) buildHostsFiles(IP string) error { hostsPath, err := container.getRootResourcePath("hosts") if err != nil { return err } container.HostsPath = hostsPath var extraContent []etchosts.Record children, err := container.daemon.Children(container.Name) if err != nil { return err } for linkAlias, child := range children { _, alias := path.Split(linkAlias) extraContent = append(extraContent, etchosts.Record{Hosts: alias, IP: child.NetworkSettings.IPAddress}) } for _, extraHost := range container.hostConfig.ExtraHosts { parts := strings.Split(extraHost, ":") extraContent = append(extraContent, etchosts.Record{Hosts: parts[0], IP: parts[1]}) } return etchosts.Build(container.HostsPath, IP, container.Config.Hostname, container.Config.Domainname, extraContent) } func (container *Container) buildHostnameAndHostsFiles(IP string) error { if err := container.buildHostnameFile(); err != nil { return err } return container.buildHostsFiles(IP) } func (container *Container) AllocateNetwork() error { mode := container.hostConfig.NetworkMode if container.Config.NetworkDisabled || !mode.IsPrivate() { return nil } var ( env *engine.Env err error eng = container.daemon.eng ) job := eng.Job("allocate_interface", container.ID) job.Setenv("RequestedMac", container.Config.MacAddress) if env, err = job.Stdout.AddEnv(); err != nil { return err } if err = job.Run(); err != nil { return err } // Error handling: At this point, the interface is allocated so we have to // make sure that it is always released in case of error, otherwise we // might leak resources. if container.Config.PortSpecs != nil { if err = migratePortMappings(container.Config, container.hostConfig); err != nil { eng.Job("release_interface", container.ID).Run() return err } container.Config.PortSpecs = nil if err = container.WriteHostConfig(); err != nil { eng.Job("release_interface", container.ID).Run() return err } } var ( portSpecs = make(nat.PortSet) bindings = make(nat.PortMap) ) if container.Config.ExposedPorts != nil { portSpecs = container.Config.ExposedPorts } if container.hostConfig.PortBindings != nil { for p, b := range container.hostConfig.PortBindings { bindings[p] = []nat.PortBinding{} for _, bb := range b { bindings[p] = append(bindings[p], nat.PortBinding{ HostIp: bb.HostIp, HostPort: bb.HostPort, }) } } } container.NetworkSettings.PortMapping = nil for port := range portSpecs { if err = container.allocatePort(eng, port, bindings); err != nil { eng.Job("release_interface", container.ID).Run() return err } } container.WriteHostConfig() container.NetworkSettings.Ports = bindings container.NetworkSettings.Bridge = env.Get("Bridge") container.NetworkSettings.IPAddress = env.Get("IP") container.NetworkSettings.IPPrefixLen = env.GetInt("IPPrefixLen") container.NetworkSettings.MacAddress = env.Get("MacAddress") container.NetworkSettings.Gateway = env.Get("Gateway") container.NetworkSettings.LinkLocalIPv6Address = env.Get("LinkLocalIPv6") container.NetworkSettings.LinkLocalIPv6PrefixLen = 64 container.NetworkSettings.GlobalIPv6Address = env.Get("GlobalIPv6") container.NetworkSettings.GlobalIPv6PrefixLen = env.GetInt("GlobalIPv6PrefixLen") container.NetworkSettings.IPv6Gateway = env.Get("IPv6Gateway") return nil } func (container *Container) ReleaseNetwork() { if container.Config.NetworkDisabled || !container.hostConfig.NetworkMode.IsPrivate() { return } eng := container.daemon.eng job := eng.Job("release_interface", container.ID) job.SetenvBool("overrideShutdown", true) job.Run() container.NetworkSettings = &NetworkSettings{} } func (container *Container) isNetworkAllocated() bool { return container.NetworkSettings.IPAddress != "" } func (container *Container) RestoreNetwork() error { mode := container.hostConfig.NetworkMode // Don't attempt a restore if we previously didn't allocate networking. // This might be a legacy container with no network allocated, in which case the // allocation will happen once and for all at start. if !container.isNetworkAllocated() || container.Config.NetworkDisabled || !mode.IsPrivate() { return nil } eng := container.daemon.eng // Re-allocate the interface with the same IP and MAC address. job := eng.Job("allocate_interface", container.ID) job.Setenv("RequestedIP", container.NetworkSettings.IPAddress) job.Setenv("RequestedMac", container.NetworkSettings.MacAddress) if err := job.Run(); err != nil { return err } // Re-allocate any previously allocated ports. for port := range container.NetworkSettings.Ports { if err := container.allocatePort(eng, port, container.NetworkSettings.Ports); err != nil { return err } } return nil } // cleanup releases any network resources allocated to the container along with any rules // around how containers are linked together. It also unmounts the container's root filesystem. func (container *Container) cleanup() { container.ReleaseNetwork() // Disable all active links if container.activeLinks != nil { for _, link := range container.activeLinks { link.Disable() } } if err := container.Unmount(); err != nil { log.Errorf("%v: Failed to umount filesystem: %v", container.ID, err) } for _, eConfig := range container.execCommands.s { container.daemon.unregisterExecCommand(eConfig) } } func (container *Container) KillSig(sig int) error { log.Debugf("Sending %d to %s", sig, container.ID) container.Lock() defer container.Unlock() // We could unpause the container for them rather than returning this error if container.Paused { return fmt.Errorf("Container %s is paused. Unpause the container before stopping", container.ID) } if !container.Running { return nil } // signal to the monitor that it should not restart the container // after we send the kill signal container.monitor.ExitOnNext() // if the container is currently restarting we do not need to send the signal // to the process. Telling the monitor that it should exit on it's next event // loop is enough if container.Restarting { return nil } return container.daemon.Kill(container, sig) } func (container *Container) Pause() error { if container.IsPaused() { return fmt.Errorf("Container %s is already paused", container.ID) } if !container.IsRunning() { return fmt.Errorf("Container %s is not running", container.ID) } return container.daemon.Pause(container) } func (container *Container) Unpause() error { if !container.IsPaused() { return fmt.Errorf("Container %s is not paused", container.ID) } if !container.IsRunning() { return fmt.Errorf("Container %s is not running", container.ID) } return container.daemon.Unpause(container) } func (container *Container) Kill() error { if !container.IsRunning() { return nil } // 1. Send SIGKILL if err := container.KillSig(9); err != nil { return err } // 2. Wait for the process to die, in last resort, try to kill the process directly if _, err := container.WaitStop(10 * time.Second); err != nil { // Ensure that we don't kill ourselves if pid := container.GetPid(); pid != 0 { log.Infof("Container %s failed to exit within 10 seconds of kill - trying direct SIGKILL", utils.TruncateID(container.ID)) if err := syscall.Kill(pid, 9); err != nil { return err } } } container.WaitStop(-1 * time.Second) return nil } func (container *Container) Stop(seconds int) error { if !container.IsRunning() { return nil } // 1. Send a SIGTERM if err := container.KillSig(15); err != nil { log.Infof("Failed to send SIGTERM to the process, force killing") if err := container.KillSig(9); err != nil { return err } } // 2. Wait for the process to exit on its own if _, err := container.WaitStop(time.Duration(seconds) * time.Second); err != nil { log.Infof("Container %v failed to exit within %d seconds of SIGTERM - using the force", container.ID, seconds) // 3. If it doesn't, then send SIGKILL if err := container.Kill(); err != nil { container.WaitStop(-1 * time.Second) return err } } return nil } func (container *Container) Restart(seconds int) error { // Avoid unnecessarily unmounting and then directly mounting // the container when the container stops and then starts // again if err := container.Mount(); err == nil { defer container.Unmount() } if err := container.Stop(seconds); err != nil { return err } return container.Start() } func (container *Container) Resize(h, w int) error { if !container.IsRunning() { return fmt.Errorf("Cannot resize container %s, container is not running", container.ID) } return container.command.ProcessConfig.Terminal.Resize(h, w) } func (container *Container) ExportRw() (archive.Archive, error) { if err := container.Mount(); err != nil { return nil, err } if container.daemon == nil { return nil, fmt.Errorf("Can't load storage driver for unregistered container %s", container.ID) } archive, err := container.daemon.Diff(container) if err != nil { container.Unmount() return nil, err } return ioutils.NewReadCloserWrapper(archive, func() error { err := archive.Close() container.Unmount() return err }), nil } func (container *Container) Export() (archive.Archive, error) { if err := container.Mount(); err != nil { return nil, err } archive, err := archive.Tar(container.basefs, archive.Uncompressed) if err != nil { container.Unmount() return nil, err } return ioutils.NewReadCloserWrapper(archive, func() error { err := archive.Close() container.Unmount() return err }), nil } func (container *Container) Mount() error { return container.daemon.Mount(container) } func (container *Container) changes() ([]archive.Change, error) { return container.daemon.Changes(container) } func (container *Container) Changes() ([]archive.Change, error) { container.Lock() defer container.Unlock() return container.changes() } func (container *Container) GetImage() (*image.Image, error) { if container.daemon == nil { return nil, fmt.Errorf("Can't get image of unregistered container") } return container.daemon.graph.Get(container.ImageID) } func (container *Container) Unmount() error { return container.daemon.Unmount(container) } func (container *Container) logPath(name string) (string, error) { return container.getRootResourcePath(fmt.Sprintf("%s-%s.log", container.ID, name)) } func (container *Container) ReadLog(name string) (io.Reader, error) { pth, err := container.logPath(name) if err != nil { return nil, err } return os.Open(pth) } func (container *Container) hostConfigPath() (string, error) { return container.getRootResourcePath("hostconfig.json") } func (container *Container) jsonPath() (string, error) { return container.getRootResourcePath("config.json") } // This method must be exported to be used from the lxc template // This directory is only usable when the container is running func (container *Container) RootfsPath() string { return container.basefs } func validateID(id string) error { if id == "" { return fmt.Errorf("Invalid empty id") } return nil } // GetSize, return real size, virtual size func (container *Container) GetSize() (int64, int64) { var ( sizeRw, sizeRootfs int64 err error driver = container.daemon.driver ) if err := container.Mount(); err != nil { log.Errorf("Warning: failed to compute size of container rootfs %s: %s", container.ID, err) return sizeRw, sizeRootfs } defer container.Unmount() initID := fmt.Sprintf("%s-init", container.ID) sizeRw, err = driver.DiffSize(container.ID, initID) if err != nil { log.Errorf("Warning: driver %s couldn't return diff size of container %s: %s", driver, container.ID, err) // FIXME: GetSize should return an error. Not changing it now in case // there is a side-effect. sizeRw = -1 } if _, err = os.Stat(container.basefs); err != nil { if sizeRootfs, err = utils.TreeSize(container.basefs); err != nil { sizeRootfs = -1 } } return sizeRw, sizeRootfs } func (container *Container) Copy(resource string) (io.ReadCloser, error) { if err := container.Mount(); err != nil { return nil, err } basePath, err := container.getResourcePath(resource) if err != nil { container.Unmount() return nil, err } // Check if this is actually in a volume for _, mnt := range container.VolumeMounts() { if len(mnt.MountToPath) > 0 && strings.HasPrefix(resource, mnt.MountToPath[1:]) { return mnt.Export(resource) } } stat, err := os.Stat(basePath) if err != nil { container.Unmount() return nil, err } var filter []string if !stat.IsDir() { d, f := path.Split(basePath) basePath = d filter = []string{f} } else { filter = []string{path.Base(basePath)} basePath = path.Dir(basePath) } archive, err := archive.TarWithOptions(basePath, &archive.TarOptions{ Compression: archive.Uncompressed, IncludeFiles: filter, }) if err != nil { container.Unmount() return nil, err } return ioutils.NewReadCloserWrapper(archive, func() error { err := archive.Close() container.Unmount() return err }), nil } // Returns true if the container exposes a certain port func (container *Container) Exposes(p nat.Port) bool { _, exists := container.Config.ExposedPorts[p] return exists } func (container *Container) GetPtyMaster() (*os.File, error) { ttyConsole, ok := container.command.ProcessConfig.Terminal.(execdriver.TtyTerminal) if !ok { return nil, ErrNoTTY } return ttyConsole.Master(), nil } func (container *Container) HostConfig() *runconfig.HostConfig { container.Lock() res := container.hostConfig container.Unlock() return res } func (container *Container) SetHostConfig(hostConfig *runconfig.HostConfig) { container.Lock() container.hostConfig = hostConfig container.Unlock() } func (container *Container) DisableLink(name string) { if container.activeLinks != nil { if link, exists := container.activeLinks[name]; exists { link.Disable() } else { log.Debugf("Could not find active link for %s", name) } } } func (container *Container) setupContainerDns() error { if container.ResolvConfPath != "" { // check if this is an existing container that needs DNS update: if container.UpdateDns { // read the host's resolv.conf, get the hash and call updateResolvConf log.Debugf("Check container (%s) for update to resolv.conf - UpdateDns flag was set", container.ID) latestResolvConf, latestHash := resolvconf.GetLastModified() // clean container resolv.conf re: localhost nameservers and IPv6 NS (if IPv6 disabled) updatedResolvConf, modified := resolvconf.FilterResolvDns(latestResolvConf, container.daemon.config.EnableIPv6) if modified { // changes have occurred during resolv.conf localhost cleanup: generate an updated hash newHash, err := utils.HashData(bytes.NewReader(updatedResolvConf)) if err != nil { return err } latestHash = newHash } if err := container.updateResolvConf(updatedResolvConf, latestHash); err != nil { return err } // successful update of the restarting container; set the flag off container.UpdateDns = false } return nil } var ( config = container.hostConfig daemon = container.daemon ) resolvConf, err := resolvconf.Get() if err != nil { return err } container.ResolvConfPath, err = container.getRootResourcePath("resolv.conf") if err != nil { return err } if config.NetworkMode != "host" { // check configurations for any container/daemon dns settings if len(config.Dns) > 0 || len(daemon.config.Dns) > 0 || len(config.DnsSearch) > 0 || len(daemon.config.DnsSearch) > 0 { var ( dns = resolvconf.GetNameservers(resolvConf) dnsSearch = resolvconf.GetSearchDomains(resolvConf) ) if len(config.Dns) > 0 { dns = config.Dns } else if len(daemon.config.Dns) > 0 { dns = daemon.config.Dns } if len(config.DnsSearch) > 0 { dnsSearch = config.DnsSearch } else if len(daemon.config.DnsSearch) > 0 { dnsSearch = daemon.config.DnsSearch } return resolvconf.Build(container.ResolvConfPath, dns, dnsSearch) } // replace any localhost/127.*, and remove IPv6 nameservers if IPv6 disabled in daemon resolvConf, _ = resolvconf.FilterResolvDns(resolvConf, daemon.config.EnableIPv6) } //get a sha256 hash of the resolv conf at this point so we can check //for changes when the host resolv.conf changes (e.g. network update) resolvHash, err := utils.HashData(bytes.NewReader(resolvConf)) if err != nil { return err } resolvHashFile := container.ResolvConfPath + ".hash" if err = ioutil.WriteFile(resolvHashFile, []byte(resolvHash), 0644); err != nil { return err } return ioutil.WriteFile(container.ResolvConfPath, resolvConf, 0644) } // called when the host's resolv.conf changes to check whether container's resolv.conf // is unchanged by the container "user" since container start: if unchanged, the // container's resolv.conf will be updated to match the host's new resolv.conf func (container *Container) updateResolvConf(updatedResolvConf []byte, newResolvHash string) error { if container.ResolvConfPath == "" { return nil } if container.Running { //set a marker in the hostConfig to update on next start/restart container.UpdateDns = true return nil } resolvHashFile := container.ResolvConfPath + ".hash" //read the container's current resolv.conf and compute the hash resolvBytes, err := ioutil.ReadFile(container.ResolvConfPath) if err != nil { return err } curHash, err := utils.HashData(bytes.NewReader(resolvBytes)) if err != nil { return err } //read the hash from the last time we wrote resolv.conf in the container hashBytes, err := ioutil.ReadFile(resolvHashFile) if err != nil { if !os.IsNotExist(err) { return err } // backwards compat: if no hash file exists, this container pre-existed from // a Docker daemon that didn't contain this update feature. Given we can't know // if the user has modified the resolv.conf since container start time, safer // to just never update the container's resolv.conf during it's lifetime which // we can control by setting hashBytes to an empty string hashBytes = []byte("") } //if the user has not modified the resolv.conf of the container since we wrote it last //we will replace it with the updated resolv.conf from the host if string(hashBytes) == curHash { log.Debugf("replacing %q with updated host resolv.conf", container.ResolvConfPath) // for atomic updates to these files, use temporary files with os.Rename: dir := path.Dir(container.ResolvConfPath) tmpHashFile, err := ioutil.TempFile(dir, "hash") if err != nil { return err } tmpResolvFile, err := ioutil.TempFile(dir, "resolv") if err != nil { return err } // write the updates to the temp files if err = ioutil.WriteFile(tmpHashFile.Name(), []byte(newResolvHash), 0644); err != nil { return err } if err = ioutil.WriteFile(tmpResolvFile.Name(), updatedResolvConf, 0644); err != nil { return err } // rename the temp files for atomic replace if err = os.Rename(tmpHashFile.Name(), resolvHashFile); err != nil { return err } return os.Rename(tmpResolvFile.Name(), container.ResolvConfPath) } return nil } func (container *Container) updateParentsHosts() error { parents, err := container.daemon.Parents(container.Name) if err != nil { return err } for _, cid := range parents { if cid == "0" { continue } c := container.daemon.Get(cid) if c != nil && !container.daemon.config.DisableNetwork && container.hostConfig.NetworkMode.IsPrivate() { if err := etchosts.Update(c.HostsPath, container.NetworkSettings.IPAddress, container.Name[1:]); err != nil { log.Errorf("Failed to update /etc/hosts in parent container: %v", err) } } } return nil } func (container *Container) initializeNetworking() error { var err error if container.hostConfig.NetworkMode.IsHost() { container.Config.Hostname, err = os.Hostname() if err != nil { return err } parts := strings.SplitN(container.Config.Hostname, ".", 2) if len(parts) > 1 { container.Config.Hostname = parts[0] container.Config.Domainname = parts[1] } content, err := ioutil.ReadFile("/etc/hosts") if os.IsNotExist(err) { return container.buildHostnameAndHostsFiles("") } else if err != nil { return err } if err := container.buildHostnameFile(); err != nil { return err } hostsPath, err := container.getRootResourcePath("hosts") if err != nil { return err } container.HostsPath = hostsPath return ioutil.WriteFile(container.HostsPath, content, 0644) } if container.hostConfig.NetworkMode.IsContainer() { // we need to get the hosts files from the container to join nc, err := container.getNetworkedContainer() if err != nil { return err } container.HostsPath = nc.HostsPath container.ResolvConfPath = nc.ResolvConfPath container.Config.Hostname = nc.Config.Hostname container.Config.Domainname = nc.Config.Domainname return nil } if container.daemon.config.DisableNetwork { container.Config.NetworkDisabled = true return container.buildHostnameAndHostsFiles("127.0.1.1") } if err := container.AllocateNetwork(); err != nil { return err } return container.buildHostnameAndHostsFiles(container.NetworkSettings.IPAddress) } // Make sure the config is compatible with the current kernel func (container *Container) verifyDaemonSettings() { if container.Config.Memory > 0 && !container.daemon.sysInfo.MemoryLimit { log.Infof("WARNING: Your kernel does not support memory limit capabilities. Limitation discarded.") container.Config.Memory = 0 } if container.Config.Memory > 0 && !container.daemon.sysInfo.SwapLimit { log.Infof("WARNING: Your kernel does not support swap limit capabilities. Limitation discarded.") container.Config.MemorySwap = -1 } if container.daemon.sysInfo.IPv4ForwardingDisabled { log.Infof("WARNING: IPv4 forwarding is disabled. Networking will not work") } } func (container *Container) setupLinkedContainers() ([]string, error) { var ( env []string daemon = container.daemon ) children, err := daemon.Children(container.Name) if err != nil { return nil, err } if len(children) > 0 { container.activeLinks = make(map[string]*links.Link, len(children)) // If we encounter an error make sure that we rollback any network // config and ip table changes rollback := func() { for _, link := range container.activeLinks { link.Disable() } container.activeLinks = nil } for linkAlias, child := range children { if !child.IsRunning() { return nil, fmt.Errorf("Cannot link to a non running container: %s AS %s", child.Name, linkAlias) } link, err := links.NewLink( container.NetworkSettings.IPAddress, child.NetworkSettings.IPAddress, linkAlias, child.Config.Env, child.Config.ExposedPorts, daemon.eng) if err != nil { rollback() return nil, err } container.activeLinks[link.Alias()] = link if err := link.Enable(); err != nil { rollback() return nil, err } for _, envVar := range link.ToEnv() { env = append(env, envVar) } } } return env, nil } func (container *Container) createDaemonEnvironment(linkedEnv []string) []string { // if a domain name was specified, append it to the hostname (see #7851) fullHostname := container.Config.Hostname if container.Config.Domainname != "" { fullHostname = fmt.Sprintf("%s.%s", fullHostname, container.Config.Domainname) } // Setup environment env := []string{ "PATH=" + DefaultPathEnv, "HOSTNAME=" + fullHostname, // Note: we don't set HOME here because it'll get autoset intelligently // based on the value of USER inside dockerinit, but only if it isn't // set already (ie, that can be overridden by setting HOME via -e or ENV // in a Dockerfile). } if container.Config.Tty { env = append(env, "TERM=xterm") } env = append(env, linkedEnv...) // because the env on the container can override certain default values // we need to replace the 'env' keys where they match and append anything // else. env = utils.ReplaceOrAppendEnvValues(env, container.Config.Env) return env } func (container *Container) setupWorkingDirectory() error { if container.Config.WorkingDir != "" { container.Config.WorkingDir = path.Clean(container.Config.WorkingDir) pth, err := container.getResourcePath(container.Config.WorkingDir) if err != nil { return err } pthInfo, err := os.Stat(pth) if err != nil { if !os.IsNotExist(err) { return err } if err := os.MkdirAll(pth, 0755); err != nil { return err } } if pthInfo != nil && !pthInfo.IsDir() { return fmt.Errorf("Cannot mkdir: %s is not a directory", container.Config.WorkingDir) } } return nil } func (container *Container) startLoggingToDisk() error { // Setup logging of stdout and stderr to disk pth, err := container.logPath("json") if err != nil { return err } if err := container.daemon.LogToDisk(container.stdout, pth, "stdout"); err != nil { return err } if err := container.daemon.LogToDisk(container.stderr, pth, "stderr"); err != nil { return err } return nil } func (container *Container) waitForStart() error { container.monitor = newContainerMonitor(container, container.hostConfig.RestartPolicy) // block until we either receive an error from the initial start of the container's // process or until the process is running in the container select { case <-container.monitor.startSignal: case err := <-promise.Go(container.monitor.Start): return err } return nil } func (container *Container) allocatePort(eng *engine.Engine, port nat.Port, bindings nat.PortMap) error { binding := bindings[port] if container.hostConfig.PublishAllPorts && len(binding) == 0 { binding = append(binding, nat.PortBinding{}) } for i := 0; i < len(binding); i++ { b := binding[i] job := eng.Job("allocate_port", container.ID) job.Setenv("HostIP", b.HostIp) job.Setenv("HostPort", b.HostPort) job.Setenv("Proto", port.Proto()) job.Setenv("ContainerPort", port.Port()) portEnv, err := job.Stdout.AddEnv() if err != nil { return err } if err := job.Run(); err != nil { return err } b.HostIp = portEnv.Get("HostIP") b.HostPort = portEnv.Get("HostPort") binding[i] = b } bindings[port] = binding return nil } func (container *Container) GetProcessLabel() string { // even if we have a process label return "" if we are running // in privileged mode if container.hostConfig.Privileged { return "" } return container.ProcessLabel } func (container *Container) GetMountLabel() string { if container.hostConfig.Privileged { return "" } return container.MountLabel } func (container *Container) getIpcContainer() (*Container, error) { containerID := container.hostConfig.IpcMode.Container() c := container.daemon.Get(containerID) if c == nil { return nil, fmt.Errorf("no such container to join IPC: %s", containerID) } if !c.IsRunning() { return nil, fmt.Errorf("cannot join IPC of a non running container: %s", containerID) } return c, nil } func (container *Container) getNetworkedContainer() (*Container, error) { parts := strings.SplitN(string(container.hostConfig.NetworkMode), ":", 2) switch parts[0] { case "container": if len(parts) != 2 { return nil, fmt.Errorf("no container specified to join network") } nc := container.daemon.Get(parts[1]) if nc == nil { return nil, fmt.Errorf("no such container to join network: %s", parts[1]) } if !nc.IsRunning() { return nil, fmt.Errorf("cannot join network of a non running container: %s", parts[1]) } return nc, nil default: return nil, fmt.Errorf("network mode not set to container") } }