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moby--moby/container/container_unix.go
Akihiro Suda 3e3d3c8086 api: fix ReadOnly support for tmpfs
For `--mount type=tmpfs,target=/foo,readonly`, the `readonly` flag was just ignored.

Signed-off-by: Akihiro Suda <suda.akihiro@lab.ntt.co.jp>
2016-11-08 06:49:17 +00:00

445 lines
13 KiB
Go

// +build linux freebsd solaris
package container
import (
"fmt"
"io/ioutil"
"os"
"path/filepath"
"strings"
"github.com/Sirupsen/logrus"
containertypes "github.com/docker/docker/api/types/container"
mounttypes "github.com/docker/docker/api/types/mount"
"github.com/docker/docker/pkg/chrootarchive"
"github.com/docker/docker/pkg/stringid"
"github.com/docker/docker/pkg/symlink"
"github.com/docker/docker/pkg/system"
"github.com/docker/docker/utils"
"github.com/docker/docker/volume"
"github.com/opencontainers/runc/libcontainer/label"
"golang.org/x/sys/unix"
)
// DefaultSHMSize is the default size (64MB) of the SHM which will be mounted in the container
const DefaultSHMSize int64 = 67108864
// Container holds the fields specific to unixen implementations.
// See CommonContainer for standard fields common to all containers.
type Container struct {
CommonContainer
// Fields below here are platform specific.
AppArmorProfile string
HostnamePath string
HostsPath string
ShmPath string
ResolvConfPath string
SeccompProfile string
NoNewPrivileges bool
}
// ExitStatus provides exit reasons for a container.
type ExitStatus struct {
// The exit code with which the container exited.
ExitCode int
// Whether the container encountered an OOM.
OOMKilled bool
}
// CreateDaemonEnvironment returns the list of all environment variables given the list of
// environment variables related to links.
// Sets PATH, HOSTNAME and if container.Config.Tty is set: TERM.
// The defaults set here do not override the values in container.Config.Env
func (container *Container) CreateDaemonEnvironment(tty bool, linkedEnv []string) []string {
// Setup environment
env := []string{
"PATH=" + system.DefaultPathEnv,
"HOSTNAME=" + container.Config.Hostname,
}
if 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
}
// TrySetNetworkMount attempts to set the network mounts given a provided destination and
// the path to use for it; return true if the given destination was a network mount file
func (container *Container) TrySetNetworkMount(destination string, path string) bool {
if destination == "/etc/resolv.conf" {
container.ResolvConfPath = path
return true
}
if destination == "/etc/hostname" {
container.HostnamePath = path
return true
}
if destination == "/etc/hosts" {
container.HostsPath = path
return true
}
return false
}
// BuildHostnameFile writes the container's hostname file.
func (container *Container) BuildHostnameFile() error {
hostnamePath, err := container.GetRootResourcePath("hostname")
if err != nil {
return err
}
container.HostnamePath = hostnamePath
return ioutil.WriteFile(container.HostnamePath, []byte(container.Config.Hostname+"\n"), 0644)
}
// appendNetworkMounts appends any network mounts to the array of mount points passed in
func appendNetworkMounts(container *Container, volumeMounts []volume.MountPoint) ([]volume.MountPoint, error) {
for _, mnt := range container.NetworkMounts() {
dest, err := container.GetResourcePath(mnt.Destination)
if err != nil {
return nil, err
}
volumeMounts = append(volumeMounts, volume.MountPoint{Destination: dest})
}
return volumeMounts, nil
}
// NetworkMounts returns the list of network mounts.
func (container *Container) NetworkMounts() []Mount {
var mounts []Mount
shared := container.HostConfig.NetworkMode.IsContainer()
if container.ResolvConfPath != "" {
if _, err := os.Stat(container.ResolvConfPath); err != nil {
logrus.Warnf("ResolvConfPath set to %q, but can't stat this filename (err = %v); skipping", container.ResolvConfPath, err)
} else {
if !container.HasMountFor("/etc/resolv.conf") {
label.Relabel(container.ResolvConfPath, container.MountLabel, shared)
}
writable := !container.HostConfig.ReadonlyRootfs
if m, exists := container.MountPoints["/etc/resolv.conf"]; exists {
writable = m.RW
}
mounts = append(mounts, Mount{
Source: container.ResolvConfPath,
Destination: "/etc/resolv.conf",
Writable: writable,
Propagation: string(volume.DefaultPropagationMode),
})
}
}
if container.HostnamePath != "" {
if _, err := os.Stat(container.HostnamePath); err != nil {
logrus.Warnf("HostnamePath set to %q, but can't stat this filename (err = %v); skipping", container.HostnamePath, err)
} else {
if !container.HasMountFor("/etc/hostname") {
label.Relabel(container.HostnamePath, container.MountLabel, shared)
}
writable := !container.HostConfig.ReadonlyRootfs
if m, exists := container.MountPoints["/etc/hostname"]; exists {
writable = m.RW
}
mounts = append(mounts, Mount{
Source: container.HostnamePath,
Destination: "/etc/hostname",
Writable: writable,
Propagation: string(volume.DefaultPropagationMode),
})
}
}
if container.HostsPath != "" {
if _, err := os.Stat(container.HostsPath); err != nil {
logrus.Warnf("HostsPath set to %q, but can't stat this filename (err = %v); skipping", container.HostsPath, err)
} else {
if !container.HasMountFor("/etc/hosts") {
label.Relabel(container.HostsPath, container.MountLabel, shared)
}
writable := !container.HostConfig.ReadonlyRootfs
if m, exists := container.MountPoints["/etc/hosts"]; exists {
writable = m.RW
}
mounts = append(mounts, Mount{
Source: container.HostsPath,
Destination: "/etc/hosts",
Writable: writable,
Propagation: string(volume.DefaultPropagationMode),
})
}
}
return mounts
}
// CopyImagePathContent copies files in destination to the volume.
func (container *Container) CopyImagePathContent(v volume.Volume, destination string) error {
rootfs, err := symlink.FollowSymlinkInScope(filepath.Join(container.BaseFS, destination), container.BaseFS)
if err != nil {
return err
}
if _, err = ioutil.ReadDir(rootfs); err != nil {
if os.IsNotExist(err) {
return nil
}
return err
}
id := stringid.GenerateNonCryptoID()
path, err := v.Mount(id)
if err != nil {
return err
}
defer func() {
if err := v.Unmount(id); err != nil {
logrus.Warnf("error while unmounting volume %s: %v", v.Name(), err)
}
}()
if err := label.Relabel(path, container.MountLabel, true); err != nil && err != unix.ENOTSUP {
return err
}
return copyExistingContents(rootfs, path)
}
// ShmResourcePath returns path to shm
func (container *Container) ShmResourcePath() (string, error) {
return container.GetRootResourcePath("shm")
}
// HasMountFor checks if path is a mountpoint
func (container *Container) HasMountFor(path string) bool {
_, exists := container.MountPoints[path]
return exists
}
// UnmountIpcMounts uses the provided unmount function to unmount shm and mqueue if they were mounted
func (container *Container) UnmountIpcMounts(unmount func(pth string) error) {
if container.HostConfig.IpcMode.IsContainer() || container.HostConfig.IpcMode.IsHost() {
return
}
var warnings []string
if !container.HasMountFor("/dev/shm") {
shmPath, err := container.ShmResourcePath()
if err != nil {
logrus.Error(err)
warnings = append(warnings, err.Error())
} else if shmPath != "" {
if err := unmount(shmPath); err != nil && !os.IsNotExist(err) {
warnings = append(warnings, fmt.Sprintf("failed to umount %s: %v", shmPath, err))
}
}
}
if len(warnings) > 0 {
logrus.Warnf("failed to cleanup ipc mounts:\n%v", strings.Join(warnings, "\n"))
}
}
// IpcMounts returns the list of IPC mounts
func (container *Container) IpcMounts() []Mount {
var mounts []Mount
if !container.HasMountFor("/dev/shm") {
label.SetFileLabel(container.ShmPath, container.MountLabel)
mounts = append(mounts, Mount{
Source: container.ShmPath,
Destination: "/dev/shm",
Writable: true,
Propagation: string(volume.DefaultPropagationMode),
})
}
return mounts
}
// UpdateContainer updates configuration of a container.
func (container *Container) UpdateContainer(hostConfig *containertypes.HostConfig) error {
container.Lock()
defer container.Unlock()
// update resources of container
resources := hostConfig.Resources
cResources := &container.HostConfig.Resources
if resources.BlkioWeight != 0 {
cResources.BlkioWeight = resources.BlkioWeight
}
if resources.CPUShares != 0 {
cResources.CPUShares = resources.CPUShares
}
if resources.CPUPeriod != 0 {
cResources.CPUPeriod = resources.CPUPeriod
}
if resources.CPUQuota != 0 {
cResources.CPUQuota = resources.CPUQuota
}
if resources.CpusetCpus != "" {
cResources.CpusetCpus = resources.CpusetCpus
}
if resources.CpusetMems != "" {
cResources.CpusetMems = resources.CpusetMems
}
if resources.Memory != 0 {
// if memory limit smaller than already set memoryswap limit and doesn't
// update the memoryswap limit, then error out.
if resources.Memory > cResources.MemorySwap && resources.MemorySwap == 0 {
return fmt.Errorf("Memory limit should be smaller than already set memoryswap limit, update the memoryswap at the same time")
}
cResources.Memory = resources.Memory
}
if resources.MemorySwap != 0 {
cResources.MemorySwap = resources.MemorySwap
}
if resources.MemoryReservation != 0 {
cResources.MemoryReservation = resources.MemoryReservation
}
if resources.KernelMemory != 0 {
cResources.KernelMemory = resources.KernelMemory
}
// update HostConfig of container
if hostConfig.RestartPolicy.Name != "" {
if container.HostConfig.AutoRemove && !hostConfig.RestartPolicy.IsNone() {
return fmt.Errorf("Restart policy cannot be updated because AutoRemove is enabled for the container")
}
container.HostConfig.RestartPolicy = hostConfig.RestartPolicy
}
if err := container.ToDisk(); err != nil {
logrus.Errorf("Error saving updated container: %v", err)
return err
}
return nil
}
// UnmountVolumes unmounts all volumes
func (container *Container) UnmountVolumes(forceSyscall bool, volumeEventLog func(name, action string, attributes map[string]string)) error {
var (
volumeMounts []volume.MountPoint
err error
)
for _, mntPoint := range container.MountPoints {
dest, err := container.GetResourcePath(mntPoint.Destination)
if err != nil {
return err
}
volumeMounts = append(volumeMounts, volume.MountPoint{Destination: dest, Volume: mntPoint.Volume, ID: mntPoint.ID})
}
// Append any network mounts to the list (this is a no-op on Windows)
if volumeMounts, err = appendNetworkMounts(container, volumeMounts); err != nil {
return err
}
for _, volumeMount := range volumeMounts {
if forceSyscall {
if err := detachMounted(volumeMount.Destination); err != nil {
logrus.Warnf("%s unmountVolumes: Failed to do lazy umount %v", container.ID, err)
}
}
if volumeMount.Volume != nil {
if err := volumeMount.Volume.Unmount(volumeMount.ID); err != nil {
return err
}
volumeMount.ID = ""
attributes := map[string]string{
"driver": volumeMount.Volume.DriverName(),
"container": container.ID,
}
volumeEventLog(volumeMount.Volume.Name(), "unmount", attributes)
}
}
return nil
}
// copyExistingContents copies from the source to the destination and
// ensures the ownership is appropriately set.
func copyExistingContents(source, destination string) error {
volList, err := ioutil.ReadDir(source)
if err != nil {
return err
}
if len(volList) > 0 {
srcList, err := ioutil.ReadDir(destination)
if err != nil {
return err
}
if len(srcList) == 0 {
// If the source volume is empty, copies files from the root into the volume
if err := chrootarchive.CopyWithTar(source, destination); err != nil {
return err
}
}
}
return copyOwnership(source, destination)
}
// copyOwnership copies the permissions and uid:gid of the source file
// to the destination file
func copyOwnership(source, destination string) error {
stat, err := system.Stat(source)
if err != nil {
return err
}
if err := os.Chown(destination, int(stat.UID()), int(stat.GID())); err != nil {
return err
}
return os.Chmod(destination, os.FileMode(stat.Mode()))
}
// TmpfsMounts returns the list of tmpfs mounts
func (container *Container) TmpfsMounts() ([]Mount, error) {
var mounts []Mount
for dest, data := range container.HostConfig.Tmpfs {
mounts = append(mounts, Mount{
Source: "tmpfs",
Destination: dest,
Data: data,
})
}
for dest, mnt := range container.MountPoints {
if mnt.Type == mounttypes.TypeTmpfs {
data, err := volume.ConvertTmpfsOptions(mnt.Spec.TmpfsOptions, mnt.Spec.ReadOnly)
if err != nil {
return nil, err
}
mounts = append(mounts, Mount{
Source: "tmpfs",
Destination: dest,
Data: data,
})
}
}
return mounts, nil
}
// cleanResourcePath cleans a resource path and prepares to combine with mnt path
func cleanResourcePath(path string) string {
return filepath.Join(string(os.PathSeparator), path)
}
// canMountFS determines if the file system for the container
// can be mounted locally. A no-op on non-Windows platforms
func (container *Container) canMountFS() bool {
return true
}
// EnableServiceDiscoveryOnDefaultNetwork Enable service discovery on default network
func (container *Container) EnableServiceDiscoveryOnDefaultNetwork() bool {
return false
}