# `Linx.Seccomp.Error`
[🔗](https://github.com/oshlabs/linx/blob/v0.2.0/lib/linx/seccomp/error.ex#L1)

A structured error returned by `Linx.Seccomp` operations.

Used for two distinct classes of failure:

  * Caller-side build failures from `Linx.Seccomp.from_rules/1` /
    `allow_list/2` / `deny_list/2` / `Linx.Seccomp.Builder.build/1`
    — `:operation` is `:build`. Most build failures use tagged
    tuples (`{:error, {:unknown_syscall, _}}`,
    `{:error, {:bad_action, _}}`, `{:error, {:duplicate_rule, _}}`,
    `{:error, {:unsupported_arch, _}}`); the struct is the home for
    build failures that don't fit those categories (notably
    `:errno` `:e2big` for filters that overflow the 255-instruction
    jump limit; trampoline-based splitting is deferred).

  * Kernel-side install failures from `Linx.Seccomp.install/2`
    that come back through `Linx.Process` as
    `{:linx_process, :error, errno, stage}` where stage is
    `:seccomp_install` or `:seccomp_no_new_privs`. The struct is
    used to normalise those errno-bearing tuples for callers that
    prefer one error type. `:operation` is `:install` or
    `:set_no_new_privs`.

## Fields

  * `:operation` — what we were trying to do, as an atom:
    `:build` | `:install` | `:set_no_new_privs`.
  * `:errno` — a POSIX errno as an atom (`:einval`, `:eperm`, …),
    or a Linx-specific atom (`:e2big` for the jump-overflow
    build failure) when nothing in the POSIX table fits.
  * `:code` — the matching positive errno integer, or `nil` for
    atoms outside the POSIX table.

Implements `Exception`, so an error can be `raise`d or rendered
with `Exception.message/1`.

# `operation`

```elixir
@type operation() :: :build | :install | :set_no_new_privs
```

# `t`

```elixir
@type t() :: %Linx.Seccomp.Error{
  __exception__: true,
  code: pos_integer() | nil,
  errno: atom(),
  operation: operation()
}
```

# `from_posix`

```elixir
@spec from_posix(atom(), operation()) :: t()
```

Builds a `%Linx.Seccomp.Error{}` from an errno atom and the
operation that failed.

---

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