# `Linx.User.Map`
[🔗](https://github.com/oshlabs/linx/blob/v0.2.0/lib/linx/user/map.ex#L1)

One uid/gid mapping entry from a user namespace's `uid_map` or
`gid_map`.

Returned by `Linx.User.read_uid_map/1` / `Linx.User.read_gid_map/1`
as a list of `%Linx.User.Map{}` — one struct per line in the
kernel's procfs file. The shape mirrors the kernel's
`inside_id outside_id length` triple exactly:

  * `:inside` — the first id in the range as the workload sees
    it (inside the user namespace).
  * `:outside` — the corresponding first id in the parent user
    namespace (outside).
  * `:length` — how many ids the range covers (≥ 1).

## Inspect

Compact rendering, chosen by length:

    # length = 1 -- just the two ids, no range syntax.
    #Linx.User.Map<0 -> 1000>

    # length > 1 -- range form on both sides.
    #Linx.User.Map<0..65535 -> 100000..165535>

## Equivalence with write-side input

The 3-tuple `{inside, outside, length}` accepted by
`Linx.User.set_uid_map/2` / `set_gid_map/2` and the
`%Linx.User.Map{}` returned by the read verbs carry exactly the
same information. A consumer that wants a clean round-trip can
convert:

    maps = [%Linx.User.Map{inside: 0, outside: 1000, length: 1}]
    mappings = Enum.map(maps, &{&1.inside, &1.outside, &1.length})
    :ok = Linx.User.set_uid_map(other_pid, mappings)

# `t`

```elixir
@type t() :: %Linx.User.Map{
  inside: non_neg_integer(),
  length: pos_integer(),
  outside: non_neg_integer()
}
```

---

*Consult [api-reference.md](api-reference.md) for complete listing*