You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: config_linux.go
    path of file: ./repos/podman/vendor/github.com/opencontainers/runc/libcontainer/configs
    
    the code of the file until where you have to start completion: package configs

import (
	"errors"
	"fmt"
	"math"
)

va
    
func (c Config) HostUID(containerId int) (int, error) {
	if c.Namespaces.Contains(NEWUSER) {
		if len(c.UIDMappings) == 0 {
			return -1, errNoUIDMap
		}
		id, found := c.hostIDFromMapping(int64(containerId), c.UIDMappings)
		if !found {
			return -1, fmt.Errorf("user namespaces enabled, but no mapping found for uid %d", containerId)
		}
		// If we are a 32-bit binary running on a 64-bit system, it's possible
		// the mapped user is too large to store in an int, which means we
		// cannot do the mapping. We can't just return an int64, because
		// os.Setuid() takes an int.
		if id > math.MaxInt {
			return -1, fmt.Errorf("mapping for uid %d (host id %d) is larger than native integer size (%d)", containerId, id, math.MaxInt)
		}
		return int(id), nil
	}
	// Return unchanged id.
	return containerId, nil
}