moby--moby/libcontainerd/utils_linux.go

package libcontainerd

import (
	containerd "github.com/docker/containerd/api/grpc/types"
	"github.com/opencontainers/specs/specs-go"
)

func getRootIDs(s specs.Spec) (int, int, error) {
	var hasUserns bool
	for _, ns := range s.Linux.Namespaces {
		if ns.Type == specs.UserNamespace {
			hasUserns = true
			break
		}
	}
	if !hasUserns {
		return 0, 0, nil
	}
	uid := hostIDFromMap(0, s.Linux.UIDMappings)
	gid := hostIDFromMap(0, s.Linux.GIDMappings)
	return uid, gid, nil
}

func hostIDFromMap(id uint32, mp []specs.IDMapping) int {
	for _, m := range mp {
		if id >= m.ContainerID && id <= m.ContainerID+m.Size-1 {
			return int(m.HostID + id - m.ContainerID)
		}
	}
	return 0
}

func systemPid(ctr *containerd.Container) uint32 {
	var pid uint32
	for _, p := range ctr.Processes {
		if p.Pid == InitFriendlyName {
			pid = p.SystemPid
		}
	}
	return pid
}