Files
podman/libpod/oci_conmon_linux.go
Giuseppe Scrivano 094bc673ef libpod: unlock the thread if possible
Signed-off-by: Giuseppe Scrivano <gscrivan@redhat.com>
2024-06-21 18:01:26 +02:00

337 lines
10 KiB
Go

//go:build !remote
package libpod
import (
"fmt"
"os"
"os/exec"
"path/filepath"
"runtime"
"strings"
runcconfig "github.com/opencontainers/runc/libcontainer/configs"
"github.com/opencontainers/runc/libcontainer/devices"
"github.com/containers/common/pkg/cgroups"
"github.com/containers/common/pkg/config"
"github.com/containers/common/pkg/systemd"
"github.com/containers/podman/v5/pkg/errorhandling"
"github.com/containers/podman/v5/pkg/rootless"
pmount "github.com/containers/storage/pkg/mount"
spec "github.com/opencontainers/runtime-spec/specs-go"
"github.com/opencontainers/selinux/go-selinux/label"
"github.com/sirupsen/logrus"
"golang.org/x/sys/unix"
)
func (r *ConmonOCIRuntime) createRootlessContainer(ctr *Container, restoreOptions *ContainerCheckpointOptions) (int64, error) {
type result struct {
restoreDuration int64
err error
}
ch := make(chan result)
go func() {
runtime.LockOSThread()
restoreDuration, err := func() (int64, error) {
fd, err := os.Open(fmt.Sprintf("/proc/%d/task/%d/ns/mnt", os.Getpid(), unix.Gettid()))
if err != nil {
return 0, err
}
defer errorhandling.CloseQuiet(fd)
// create a new mountns on the current thread
if err = unix.Unshare(unix.CLONE_NEWNS); err != nil {
return 0, err
}
defer func() {
err := unix.Setns(int(fd.Fd()), unix.CLONE_NEWNS)
if err == nil {
// If we are able to reset the previous mount namespace, unlock the thread and reuse it
runtime.UnlockOSThread()
} else {
// otherwise, leave the thread locked and the Go runtime will terminate it
logrus.Errorf("Unable to reset the previous mount namespace: %q", err)
}
}()
// don't spread our mounts around. We are setting only /sys to be slave
// so that the cleanup process is still able to umount the storage and the
// changes are propagated to the host.
err = unix.Mount("/sys", "/sys", "none", unix.MS_REC|unix.MS_SLAVE, "")
if err != nil {
return 0, fmt.Errorf("cannot make /sys slave: %w", err)
}
mounts, err := pmount.GetMounts()
if err != nil {
return 0, err
}
for _, m := range mounts {
if !strings.HasPrefix(m.Mountpoint, "/sys/kernel") {
continue
}
err = unix.Unmount(m.Mountpoint, 0)
if err != nil && !os.IsNotExist(err) {
return 0, fmt.Errorf("cannot unmount %s: %w", m.Mountpoint, err)
}
}
return r.createOCIContainer(ctr, restoreOptions)
}()
ch <- result{
restoreDuration: restoreDuration,
err: err,
}
}()
res := <-ch
return res.restoreDuration, res.err
}
// Run the closure with the container's socket label set
func (r *ConmonOCIRuntime) withContainerSocketLabel(ctr *Container, closure func() error) error {
runtime.LockOSThread()
if err := label.SetSocketLabel(ctr.ProcessLabel()); err != nil {
return err
}
err := closure()
// Ignore error returned from SetSocketLabel("") call,
// can't recover.
if labelErr := label.SetSocketLabel(""); labelErr == nil {
// Unlock the thread only if the process label could be restored
// successfully. Otherwise leave the thread locked and the Go runtime
// will terminate it once it returns to the threads pool.
runtime.UnlockOSThread()
} else {
logrus.Errorf("Unable to reset socket label: %q", labelErr)
}
return err
}
// moveConmonToCgroupAndSignal gets a container's cgroupParent and moves the conmon process to that cgroup
// it then signals for conmon to start by sending nonce data down the start fd
func (r *ConmonOCIRuntime) moveConmonToCgroupAndSignal(ctr *Container, cmd *exec.Cmd, startFd *os.File) error {
mustCreateCgroup := true
if ctr.config.NoCgroups {
mustCreateCgroup = false
}
// If cgroup creation is disabled - just signal.
switch ctr.config.CgroupsMode {
case "disabled", "no-conmon", cgroupSplit:
mustCreateCgroup = false
}
// $INVOCATION_ID is set by systemd when running as a service.
if ctr.runtime.RemoteURI() == "" && os.Getenv("INVOCATION_ID") != "" {
mustCreateCgroup = false
}
if mustCreateCgroup {
// Usually rootless users are not allowed to configure cgroupfs.
// There are cases though, where it is allowed, e.g. if the cgroup
// is manually configured and chowned). Avoid detecting all
// such cases and simply use a lower log level.
logLevel := logrus.WarnLevel
if rootless.IsRootless() {
logLevel = logrus.InfoLevel
}
// TODO: This should be a switch - we are not guaranteed that
// there are only 2 valid cgroup managers
cgroupParent := ctr.CgroupParent()
cgroupPath := filepath.Join(ctr.config.CgroupParent, "conmon")
cgroupResources, err := GetLimits(ctr.LinuxResources())
if err != nil {
logrus.StandardLogger().Log(logLevel, "Could not get ctr resources")
}
if ctr.CgroupManager() == config.SystemdCgroupsManager {
unitName := createUnitName("libpod-conmon", ctr.ID())
realCgroupParent := cgroupParent
splitParent := strings.Split(cgroupParent, "/")
if strings.HasSuffix(cgroupParent, ".slice") && len(splitParent) > 1 {
realCgroupParent = splitParent[len(splitParent)-1]
}
logrus.Infof("Running conmon under slice %s and unitName %s", realCgroupParent, unitName)
if err := systemd.RunUnderSystemdScope(cmd.Process.Pid, realCgroupParent, unitName); err != nil {
logrus.StandardLogger().Logf(logLevel, "Failed to add conmon to systemd sandbox cgroup: %v", err)
}
} else {
control, err := cgroups.New(cgroupPath, &cgroupResources)
if err != nil {
logrus.StandardLogger().Logf(logLevel, "Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
} else if err := control.AddPid(cmd.Process.Pid); err != nil {
// we need to remove this defer and delete the cgroup once conmon exits
// maybe need a conmon monitor?
logrus.StandardLogger().Logf(logLevel, "Failed to add conmon to cgroupfs sandbox cgroup: %v", err)
}
}
}
/* We set the cgroup, now the child can start creating children */
return writeConmonPipeData(startFd)
}
// GetLimits converts spec resource limits to cgroup consumable limits
func GetLimits(resource *spec.LinuxResources) (runcconfig.Resources, error) {
if resource == nil {
resource = &spec.LinuxResources{}
}
final := &runcconfig.Resources{}
devs := []*devices.Rule{}
// Devices
for _, entry := range resource.Devices {
if entry.Major == nil || entry.Minor == nil {
continue
}
runeType := 'a'
switch entry.Type {
case "b":
runeType = 'b'
case "c":
runeType = 'c'
}
devs = append(devs, &devices.Rule{
Type: devices.Type(runeType),
Major: *entry.Major,
Minor: *entry.Minor,
Permissions: devices.Permissions(entry.Access),
Allow: entry.Allow,
})
}
final.Devices = devs
// HugepageLimits
pageLimits := []*runcconfig.HugepageLimit{}
for _, entry := range resource.HugepageLimits {
pageLimits = append(pageLimits, &runcconfig.HugepageLimit{
Pagesize: entry.Pagesize,
Limit: entry.Limit,
})
}
final.HugetlbLimit = pageLimits
// Networking
netPriorities := []*runcconfig.IfPrioMap{}
if resource.Network != nil {
for _, entry := range resource.Network.Priorities {
netPriorities = append(netPriorities, &runcconfig.IfPrioMap{
Interface: entry.Name,
Priority: int64(entry.Priority),
})
}
}
final.NetPrioIfpriomap = netPriorities
rdma := make(map[string]runcconfig.LinuxRdma)
for name, entry := range resource.Rdma {
rdma[name] = runcconfig.LinuxRdma{HcaHandles: entry.HcaHandles, HcaObjects: entry.HcaObjects}
}
final.Rdma = rdma
// Memory
if resource.Memory != nil {
if resource.Memory.Limit != nil {
final.Memory = *resource.Memory.Limit
}
if resource.Memory.Reservation != nil {
final.MemoryReservation = *resource.Memory.Reservation
}
if resource.Memory.Swap != nil {
final.MemorySwap = *resource.Memory.Swap
}
if resource.Memory.Swappiness != nil {
final.MemorySwappiness = resource.Memory.Swappiness
}
}
// CPU
if resource.CPU != nil {
if resource.CPU.Period != nil {
final.CpuPeriod = *resource.CPU.Period
}
if resource.CPU.Quota != nil {
final.CpuQuota = *resource.CPU.Quota
}
if resource.CPU.RealtimePeriod != nil {
final.CpuRtPeriod = *resource.CPU.RealtimePeriod
}
if resource.CPU.RealtimeRuntime != nil {
final.CpuRtRuntime = *resource.CPU.RealtimeRuntime
}
if resource.CPU.Shares != nil {
final.CpuShares = *resource.CPU.Shares
}
final.CpusetCpus = resource.CPU.Cpus
final.CpusetMems = resource.CPU.Mems
}
// BlkIO
if resource.BlockIO != nil {
if len(resource.BlockIO.ThrottleReadBpsDevice) > 0 {
for _, entry := range resource.BlockIO.ThrottleReadBpsDevice {
throttle := runcconfig.NewThrottleDevice(entry.Major, entry.Minor, entry.Rate)
final.BlkioThrottleReadBpsDevice = append(final.BlkioThrottleReadBpsDevice, throttle)
}
}
if len(resource.BlockIO.ThrottleWriteBpsDevice) > 0 {
for _, entry := range resource.BlockIO.ThrottleWriteBpsDevice {
throttle := runcconfig.NewThrottleDevice(entry.Major, entry.Minor, entry.Rate)
final.BlkioThrottleWriteBpsDevice = append(final.BlkioThrottleWriteBpsDevice, throttle)
}
}
if len(resource.BlockIO.ThrottleReadIOPSDevice) > 0 {
for _, entry := range resource.BlockIO.ThrottleReadIOPSDevice {
throttle := runcconfig.NewThrottleDevice(entry.Major, entry.Minor, entry.Rate)
final.BlkioThrottleReadIOPSDevice = append(final.BlkioThrottleReadIOPSDevice, throttle)
}
}
if len(resource.BlockIO.ThrottleWriteIOPSDevice) > 0 {
for _, entry := range resource.BlockIO.ThrottleWriteIOPSDevice {
throttle := runcconfig.NewThrottleDevice(entry.Major, entry.Minor, entry.Rate)
final.BlkioThrottleWriteIOPSDevice = append(final.BlkioThrottleWriteIOPSDevice, throttle)
}
}
if resource.BlockIO.LeafWeight != nil {
final.BlkioLeafWeight = *resource.BlockIO.LeafWeight
}
if resource.BlockIO.Weight != nil {
final.BlkioWeight = *resource.BlockIO.Weight
}
if len(resource.BlockIO.WeightDevice) > 0 {
for _, entry := range resource.BlockIO.WeightDevice {
var w, lw uint16
if entry.Weight != nil {
w = *entry.Weight
}
if entry.LeafWeight != nil {
lw = *entry.LeafWeight
}
weight := runcconfig.NewWeightDevice(entry.Major, entry.Minor, w, lw)
final.BlkioWeightDevice = append(final.BlkioWeightDevice, weight)
}
}
}
// Pids
if resource.Pids != nil {
final.PidsLimit = resource.Pids.Limit
}
// Networking
if resource.Network != nil {
if resource.Network.ClassID != nil {
final.NetClsClassid = *resource.Network.ClassID
}
}
// Unified state
final.Unified = resource.Unified
return *final, nil
}
func moveToRuntimeCgroup() error {
return cgroups.MoveUnderCgroupSubtree("runtime")
}