API cleanup, C improvements, docs, ...

2020-06-16 11:55:04 +02:00 · 2020-06-16 11:55:04 +02:00 · debcadf495
commit debcadf495
parent 34c2d22e77
17 changed files with 306 additions and 156 deletions
--- a/.gitignore
+++ b/.gitignore
@ -7,6 +7,6 @@ erl_crash.dump
 *.ez
 *.beam
 /config/*.secret.exs
-/priv/apprentice
-/src/*.o
+/priv/libmagic_port
 /test/*.mgc
+core.*
--- a/.travis.yml
+++ b/.travis.yml
@ -4,15 +4,15 @@ elixir:
  - 1.10
  - 1.9
  - 1.8
-  - 1.7

 otp_release:
-  - '22.2'
+  - '22.3'
+  - '23.0.2'

 before_script:
  - mix compile –warnings-as-errors
  - mix credo --strict
-  - if [[ "$TRAVIS_ELIXIR_VERSION" =~ "1.10" ]]; then mix format mix.exs "{config,clients,games,lib,test}/**/*.{ex,exs}" --check-formatted; fi
+  - if [[ "$TRAVIS_ELIXIR_VERSION" =~ "1.10" ]]; then mix format mix.exs "{config,lib,test}/**/*.{ex,exs}" --check-formatted; fi

 before_install:
  - sudo apt-get install -y build-essential erlang-dev libmagic-dev
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@ -18,12 +18,13 @@ The format is based on [Keep a Changelog][1], and this project adheres to [Seman
 ## Changed

 - C port now using erl_interface
+- Builds on Musl
+- Better error and timeout handling
 - `Majic.Server.reload/2,3`
 - `Majic.Server.recycle/2,3`
 - Bytes support: `Majic.Server.perform(ref, {:bytes, <<>>})`
- Builds on Musl
- Better error and timeout handling
 - Renamed `priv/apprentice` to `priv/libmagic_port` to be more obvious in `ps`
+- Renamed `Majic.Helpers.perform_once` to `Majic.Once.perform`

 ## gen_majic [1.0]

--- a/README.md
+++ b/README.md
@ -31,7 +31,7 @@ Compilation of the underlying C program is automatic and handled by [elixir_make

 Depending on the use case, you may utilise a single (one-off) Majic process without reusing it as a daemon, or utilise a connection pool (such as Poolboy) in your application to run multiple persistent Majic processes.

-To use Majic directly, you can use `Majic.Helpers.perform_once/1`:
+To use Majic directly, you can use `Majic.Once.perform/1`:

 ```elixir
 iex(1)> Majic.perform(".", once: true)
@ -67,11 +67,23 @@ When using `Majic.Server.start_link/1` to start a persistent server, or `Majic.H

 See `t:Majic.Server.option/0` for details.

+__Note__ `:recycle_thresold` is only useful if you are using a libmagic `<5.29`, where it was susceptible to memleaks
+([details](https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=840754)]). In future versions of `majic` this option could
+be ignored.
+
+### Reloading / Altering databases
+
+If you want `majic` to reload its database(s), run `Majic.Server.reload(ref)`.
+
+If you want to add or remove databases to a running server, you would have to run `Majic.Server.reload(ref, databases)`
+where databases being the same argument as `database_patterns` on start. `Majic` does not support adding/removing
+databases at runtime without a port reload.
+
 ### Use Cases

-### Ad-Hoc Requests
+#### Ad-Hoc Requests

-For ad-hoc requests, you can use the helper method `Majic.Helpers.perform_once/2`:
+For ad-hoc requests, you can use the helper method `Majic.Once.perform_once/2`:

 ```elixir
 iex(1)> Majic.perform(Path.join(File.cwd!(), "Makefile"), once: true)
@ -83,34 +95,40 @@ iex(1)> Majic.perform(Path.join(File.cwd!(), "Makefile"), once: true)
 }}
 ```

-### Supervised Requests
+#### Supervised Requests

 The Server should be run under a supervisor which provides resiliency.

-Here we run it under a supervisor:
+Here we run it under a supervisor in an application:

 ```elixir
-iex(1)> {:ok, pid} = Supervisor.start_link([{Majic.Server, name: :gen_magic}], strategy: :one_for_one)
-{:ok, #PID<0.199.0>}
+children =
+  [
+    # ...
+    {Majic.Server, [name: YourApp.Majic]}
+  ]
+
+opts = [strategy: :one_for_one, name: YourApp.Supervisor]
+Supervisor.start_link(children, opts)
 ```

 Now we can ask it to inspect a file:

 ```elixir
-iex(2)> Majic.perform(Path.expand("~/.bash_history"), server: :gen_magic)
+iex(2)> Majic.perform(Path.expand("~/.bash_history"), server: YourApp.Majic)
 {:ok, %Majic.Result{mime_type: "text/plain", encoding: "us-ascii", content: "ASCII text"}}
 ```

 Note that in this case we have opted to use a named process.

-### Pool
+#### Pool

 For concurrency *and* resiliency, you may start the `Majic.Pool`. By default, it will start a `Majic.Server`
 worker per online scheduler:

 You can add a pool in your application supervisor by adding it as a child:

-```
+```elixir
 children =
  [
    # ...
@ -123,23 +141,18 @@ You can add a pool in your application supervisor by adding it as a child:

 And then you can use it with `Majic.perform/2` with `pool: YourApp.MajicPool` option:

-```
+```elixir
 iex(1)> Majic.perform(Path.expand("~/.bash_history"), pool: YourApp.MajicPool)
 {:ok, %Majic.Result{mime_type: "text/plain", encoding: "us-ascii", content: "ASCII text"}}
 ```

-### Check Uploaded Files
+#### Use with Plug.Upload

-If you use Phoenix, you can inspect the file from your controller:
+If you use Plug or Phoenix, you may want to automatically verify the content type of every `Plug.Upload`. The
+`Majic.Plug` is there for this.

-```elixir
-def upload(conn, %{"upload" => %{path: path}}) do,
-  {:ok, result} = Majic.perform(path, server: :gen_magic)
-  text(conn, "Received your file containing #{result.content}")
-end
-```
-
-Obviously, it will be more ideal if you have wrapped `Majic.Server` in a pool such as Poolboy, to avoid constantly starting and stopping the underlying C program.
+Enable it by using `plug Majic.Plug, pool: YourApp.MajicPool` in your pipeline or controller. Then, every `Plug.Upload`
+in `conn.params` is now verified. The filename is also altered with an extension matching its content-type.

 ## Notes

@ -165,3 +178,4 @@ thanks all contributors for their generosity:
  - Soak Testing
 - Matthias and Ced for helping the author with C oddities
 - [Hecate](https://github.com/Kleidukos) for laughing at aforementionned oddities
+- majic for giving inspiration for the lib name (magic, majic, get it? hahaha..)
--- a/lib/majic.ex
+++ b/lib/majic.ex
@ -1,34 +1,51 @@
 defmodule Majic do
+  alias Majic.{Once, Pool, Result, Server}
+
+  @moduledoc """
+  Robust libmagic integration for Elixir.
+  """
+
  @doc """
  Perform on `path`.

  An option of `server: ServerName`, `pool: PoolName` or `once: true` must be passed.
  """
-  @type name :: {:pool, atom()} | {:server, GenMagic.Server.t()} | {:once, true}
-  @type option :: name
+  @type target :: Path.t() | {:bytes, binary()}
+  @type result :: {:ok, Result.t()} | {:error, term() | String.t()}
+  @type name :: {:pool, atom()} | {:server, Server.t()} | {:once, true}
+  @type option :: name | Server.start_option() | Pool.option()

-  @spec perform(GenMagic.Server.target(), [option()]) :: GenMagic.Server.result()
-  def perform(path, opts, timeout \\ 5000) do
-    mod = cond do
-      Keyword.has_key?(opts, :pool) -> {GenMagic.Pool, Keyword.get(opts, :pool)}
-      Keyword.has_key?(opts, :server) -> {GenMagic.Server, Keyword.get(opts, :server)}
-      Keyword.has_key?(opts, :once) -> {GenMagic.Helpers, nil}
+  @spec perform(target(), [option()]) :: result()
+  def perform(path, opts) do
+    mod =
+      cond do
+        Keyword.has_key?(opts, :pool) -> {Pool, Keyword.get(opts, :pool)}
+        Keyword.has_key?(opts, :server) -> {Server, Keyword.get(opts, :server)}
+        Keyword.has_key?(opts, :once) -> {Once, nil}
        true -> nil
      end

+    opts =
+      opts
+      |> Keyword.drop([:pool, :server, :once])
+
    if mod do
-      do_perform(mod, path, timeout)
+      do_perform(mod, path, opts)
    else
      {:error, :no_method}
    end
  end

-  defp do_perform({GenMagic.Helpers, _}, path, timeout) do
-    GenMagic.Helpers.perform_once(path, timeout)
-  end
-
-  defp do_perform({mod, name}, path, timeout) do
+  defp do_perform({Server = mod, name}, path, opts) do
+    timeout = Keyword.get(opts, :timeout, Majic.Config.default_process_timeout())
    mod.perform(name, path, timeout)
  end

+  defp do_perform({Once = mod, _}, path, opts) do
+    mod.perform(path, opts)
+  end
+
+  defp do_perform({Pool = mod, name}, path, opts) do
+    mod.perform(name, path, opts)
+  end
 end
--- a/lib/majic/config.ex
+++ b/lib/majic/config.ex
@ -6,6 +6,8 @@ defmodule Majic.Config do
  @process_timeout 30_000
  @recycle_threshold :infinity

+  def default_process_timeout, do: @process_timeout
+
  def get_port_name do
    {:spawn_executable, to_charlist(get_executable_name())}
  end
--- a/lib/majic/helpers.ex
+++ b/lib/majic/helpers.ex
@ -1,13 +1,13 @@
-defmodule Majic.Helpers do
+defmodule Majic.Once do
  @moduledoc """
  Contains convenience functions for one-off use.
  """

-  alias Majic.Result
  alias Majic.Server

-  @spec perform_once(Path.t() | {:bytes, binary}, [Server.option()]) ::
-          {:ok, Result.t()} | {:error, term()}
+  @process_timeout Majic.Config.default_process_timeout()
+
+  @spec perform(Majic.target(), [Server.start_option()], timeout()) :: Majic.result()

  @doc """
  Runs a one-shot process without supervision.
@ -16,13 +16,13 @@ defmodule Majic.Helpers do

  ## Example

-      iex(1)> {:ok, result} = Majic.Helpers.perform_once(".")
+      iex(1)> {:ok, result} = Majic.Once.perform(".")
      iex(2)> result
      %Majic.Result{content: "directory", encoding: "binary", mime_type: "inode/directory"}
  """
-  def perform_once(path, options \\ []) do
+  def perform(path, options \\ [], timeout \\ @process_timeout) do
    with {:ok, pid} <- Server.start_link(options),
-         {:ok, result} <- Server.perform(pid, path),
+         {:ok, result} <- Server.perform(pid, path, timeout),
         :ok <- Server.stop(pid) do
      {:ok, result}
    end
--- a/lib/majic/pool.ex
+++ b/lib/majic/pool.ex
@ -2,6 +2,9 @@ defmodule Majic.Pool do
  @behaviour NimblePool
  @moduledoc "Pool of `Majic.Server`"

+  @type name :: atom()
+  @type option :: {:pool_timeout, timeout()} | {:timeout, timeout()}
+
  def child_spec(opts) do
    %{
      id: __MODULE__,
@ -17,9 +20,10 @@ defmodule Majic.Pool do
    NimblePool.start_link(worker: {__MODULE__, options}, pool_size: pool_size)
  end

+  @spec perform(name(), Majic.target(), [option()]) :: Majic.result()
  def perform(pool, path, opts \\ []) do
-    pool_timeout = Keyword.get(opts, :pool_timeout, 5000)
-    timeout = Keyword.get(opts, :timeout, 5000)
+    pool_timeout = Keyword.get(opts, :pool_timeout, Majic.Config.default_process_timeout())
+    timeout = Keyword.get(opts, :timeout, Majic.Config.default_process_timeout())

    NimblePool.checkout!(
      pool,
--- a/lib/majic/server.ex
+++ b/lib/majic/server.ex
@ -10,7 +10,8 @@ defmodule Majic.Server do
  alias Majic.Server.Data
  alias Majic.Server.Status
  import Kernel, except: [send: 2]
-  require Logger
+  @database_patterns [:default]
+  @process_timeout Majic.Config.default_process_timeout()

  @typedoc """
  Represents the reference to the underlying server, as returned by `:gen_statem`.
@ -41,7 +42,7 @@ defmodule Majic.Server do

    Can be set to `:infinity` if you do not wish for the program to be recycled.

-  - `:database_patterns`: Specifies what magic databases to load; you can specify a list of either
+  - `:database_patterns`: Specifies what magic databases to load; you can specify a list of files, or of
    Path Patterns (see `Path.wildcard/2`) or `:default` to instruct the C program to load the
    appropriate databases.

@ -49,17 +50,13 @@ defmodule Majic.Server do

        [:default, "path/to/my/magic"]
  """
-  @database_patterns [:default]
-  @type option ::
+  @type start_option ::
          {:name, atom() | :gen_statem.server_name()}
          | {:startup_timeout, timeout()}
          | {:process_timeout, timeout()}
          | {:recycle_threshold, non_neg_integer() | :infinity}
          | {:database_patterns, nonempty_list(:default | Path.t())}

-  @type target :: Path.t() | {:bytes, binary()}
-  @type result :: {:ok, Result.t()} | {:error, term() | String.t()}
-
  @typedoc """
  Current state of the Server:

@ -84,9 +81,9 @@ defmodule Majic.Server do
  """
  @type state :: :starting | :processing | :available | :recycling

-  @spec child_spec([option()]) :: Supervisor.child_spec()
-  @spec start_link([option()]) :: :gen_statem.start_ret()
-  @spec perform(t(), target(), timeout()) :: result()
+  @spec child_spec([start_option()]) :: Supervisor.child_spec()
+  @spec start_link([start_option()]) :: :gen_statem.start_ret()
+  @spec perform(t(), Majic.target(), timeout()) :: Majic.result()
  @spec status(t(), timeout()) :: {:ok, Status.t()} | {:error, term()}
  @spec stop(t(), term(), timeout()) :: :ok

@ -125,7 +122,7 @@ defmodule Majic.Server do
  @doc """
  Determines the type of the file provided.
  """
-  def perform(server_ref, path, timeout \\ 5000) do
+  def perform(server_ref, path, timeout \\ @process_timeout) do
    case :gen_statem.call(server_ref, {:perform, path}, timeout) do
      {:ok, %Result{} = result} -> {:ok, result}
      {:error, reason} -> {:error, reason}
@ -135,21 +132,21 @@ defmodule Majic.Server do
  @doc """
  Reloads a Server with a new set of databases.
  """
-  def reload(server_ref, database_patterns \\ nil, timeout \\ 5000) do
+  def reload(server_ref, database_patterns \\ nil, timeout \\ @process_timeout) do
    :gen_statem.call(server_ref, {:reload, database_patterns}, timeout)
  end

  @doc """
  Same as `reload/2,3` but with a full restart of the underlying C port.
  """
-  def recycle(server_ref, database_patterns \\ nil, timeout \\ 5000) do
+  def recycle(server_ref, database_patterns \\ nil, timeout \\ @process_timeout) do
    :gen_statem.call(server_ref, {:recycle, database_patterns}, timeout)
  end

  @doc """
  Returns status of the Server.
  """
-  def status(server_ref, timeout \\ 5000) do
+  def status(server_ref, timeout \\ @process_timeout) do
    :gen_statem.call(server_ref, :status, timeout)
  end

@ -173,7 +170,7 @@ defmodule Majic.Server do

    data = %Data{
      port_name: get_port_name(),
-      database_patterns: Keyword.get(options, :database_patterns, []),
+      database_patterns: Keyword.get(options, :database_patterns),
      port_options: get_port_options(options),
      startup_timeout: get_startup_timeout(options),
      process_timeout: get_process_timeout(options),
@ -223,6 +220,7 @@ defmodule Majic.Server do
        1 -> :bad_db
        2 -> :ei_error
        3 -> :ei_bad_term
+        4 -> :magic_error
        code -> {:unexpected_error, code}
      end

@ -237,15 +235,12 @@ defmodule Majic.Server do
        pattern -> Path.wildcard(pattern)
      end)

-    databases =
    if databases == [] do
-        [:default]
+      {:stop, {:error, :no_databases_to_load}, data}
    else
-        databases
-      end
-
      {:keep_state, {databases, data}, {:state_timeout, 0, :load}}
    end
+  end

  @doc false
  def loading(:state_timeout, :load_timeout, {[database | _], data}) do
@ -258,11 +253,11 @@ defmodule Majic.Server do
  end

  @doc false
-  def loading(:state_timeout, :load, {[database | databases], data} = state) do
+  def loading(:state_timeout, :load, {[database | _databases], data} = state) do
    command =
      case database do
        :default -> {:add_default_database, nil}
-        path -> {:add_database, database}
+        path -> {:add_database, path}
      end

    send(data.port, command)
@ -274,16 +269,14 @@ defmodule Majic.Server do
    case :erlang.binary_to_term(response) do
      {:ok, :loaded} ->
        {:keep_state, {databases, data}, {:state_timeout, 0, :load}}
+
+      {:error, :not_loaded} ->
+        {:stop, {:error, {:database_load_failed, database}}, data}
    end
  end

  @doc false
-  def loading(:info, {port, {:exit_status, 1}}, {[database | _], %{port: port} = data}) do
-    {:stop, {:error, {:database_not_found, database}}, data}
-  end
-
-  @doc false
-  def loading({:call, from}, :status, {[database | _], data}) do
+  def loading({:call, from}, :status, {_, data}) do
    handle_status_call(from, :loading, data)
  end

@ -310,6 +303,8 @@ defmodule Majic.Server do
    arg =
      case path do
        path when is_binary(path) -> {:file, path}
+        # Truncate to 50 bytes
+        {:bytes, <<bytes::size(50), _::binary>>} -> {:bytes, bytes}
        {:bytes, bytes} -> {:bytes, bytes}
      end

@ -360,7 +355,7 @@ defmodule Majic.Server do
  end

  @doc false
-  def processing(:state_timeout, _, %{port: port, request: {_, from, _}} = data) do
+  def processing(:state_timeout, _, %{request: {_, from, _}} = data) do
    response = {:reply, from, {:error, :timeout}}
    {:next_state, :recycling, %{data | request: nil}, [response, :hibernate]}
  end
@ -397,7 +392,7 @@ defmodule Majic.Server do

  @doc false
  def recycling(:state_timeout, :close, data) do
-    {:stop, {:error, :port_close_failed}}
+    {:stop, {:error, :port_close_failed}, data}
  end

  @doc false
--- a/mix.exs
+++ b/mix.exs
@ -11,6 +11,7 @@ defmodule Majic.MixProject do
      version: "1.0.0",
      elixir: "~> 1.7",
      elixirc_paths: elixirc_paths(Mix.env()),
+      elixirc_options: [warnings_as_errors: warnings_as_errors(Mix.env())],
      start_permanent: Mix.env() == :prod,
      compilers: [:elixir_make] ++ Mix.compilers(),
      package: package(),
@ -32,7 +33,7 @@ defmodule Majic.MixProject do

  defp dialyzer do
    [
-      plt_add_apps: [:mix, :iex, :ex_unit],
+      plt_add_apps: [:mix, :iex, :ex_unit, :plug, :mime],
      flags: ~w(error_handling no_opaque race_conditions underspecs unmatched_returns)a,
      ignore_warnings: "dialyzer-ignore-warnings.exs",
      list_unused_filters: true
@ -41,11 +42,13 @@ defmodule Majic.MixProject do

  defp deps do
    [
-      {:credo, "~> 1.4.0", only: [:dev, :test], runtime: false},
+      {:nimble_pool, "~> 0.1"},
+      {:plug, "~> 1.0", optional: true},
+      {:mime, "~> 1.0", optional: true},
+      {:credo, "~> 1.4", only: [:dev, :test], runtime: false},
      {:dialyxir, "~> 1.0.0-rc.6", only: :dev, runtime: false},
      {:ex_doc, ">= 0.0.0", only: :dev, runtime: false},
-      {:elixir_make, "~> 0.4", runtime: false},
-      {:nimble_pool, "~> 0.1"}
+      {:elixir_make, "~> 0.4", runtime: false}
    ]
  end

@ -53,8 +56,8 @@ defmodule Majic.MixProject do
    [
      files: ~w(lib/gen_magic/* src/*.c Makefile),
      licenses: ["Apache 2.0"],
-      links: %{"GitHub" => "https://github.com/evadne/packmatic"},
-      source_url: "https://github.com/evadne/packmatic"
+      links: %{"GitHub" => "https://github.com/hrefhref/majic"},
+      source_url: "https://github.com/hrefhref/majic"
    ]
  end

@ -64,4 +67,7 @@ defmodule Majic.MixProject do
      extras: ["README.md", "CHANGELOG.md"]
    ]
  end
+
+  defp warnings_as_errors(:dev), do: false
+  defp warnings_as_errors(_), do: true
 end
--- a/mix.lock
+++ b/mix.lock
@ -2,15 +2,19 @@
  "bunt": {:hex, :bunt, "0.2.0", "951c6e801e8b1d2cbe58ebbd3e616a869061ddadcc4863d0a2182541acae9a38", [:mix], [], "hexpm", "7af5c7e09fe1d40f76c8e4f9dd2be7cebd83909f31fee7cd0e9eadc567da8353"},
  "credo": {:hex, :credo, "1.4.0", "92339d4cbadd1e88b5ee43d427b639b68a11071b6f73854e33638e30a0ea11f5", [:mix], [{:bunt, "~> 0.2.0", [hex: :bunt, repo: "hexpm", optional: false]}, {:jason, "~> 1.0", [hex: :jason, repo: "hexpm", optional: false]}], "hexpm", "1fd3b70dce216574ce3c18bdf510b57e7c4c85c2ec9cad4bff854abaf7e58658"},
  "dialyxir": {:hex, :dialyxir, "1.0.0", "6a1fa629f7881a9f5aaf3a78f094b2a51a0357c843871b8bc98824e7342d00a5", [:mix], [{:erlex, ">= 0.2.6", [hex: :erlex, repo: "hexpm", optional: false]}], "hexpm", "aeb06588145fac14ca08d8061a142d52753dbc2cf7f0d00fc1013f53f8654654"},
-  "earmark": {:hex, :earmark, "1.4.4", "4821b8d05cda507189d51f2caeef370cf1e18ca5d7dfb7d31e9cafe6688106a4", [:mix], [], "hexpm", "1f93aba7340574847c0f609da787f0d79efcab51b044bb6e242cae5aca9d264d"},
+  "earmark": {:hex, :earmark, "1.4.5", "62ffd3bd7722fb7a7b1ecd2419ea0b458c356e7168c1f5d65caf09b4fbdd13c8", [:mix], [], "hexpm", "b7d0e6263d83dc27141a523467799a685965bf8b13b6743413f19a7079843f4f"},
  "elixir_make": {:hex, :elixir_make, "0.6.0", "38349f3e29aff4864352084fc736fa7fa0f2995a819a737554f7ebd28b85aaab", [:mix], [], "hexpm", "d522695b93b7f0b4c0fcb2dfe73a6b905b1c301226a5a55cb42e5b14d509e050"},
  "erlex": {:hex, :erlex, "0.2.6", "c7987d15e899c7a2f34f5420d2a2ea0d659682c06ac607572df55a43753aa12e", [:mix], [], "hexpm", "2ed2e25711feb44d52b17d2780eabf998452f6efda104877a3881c2f8c0c0c75"},
  "erlexec": {:hex, :erlexec, "1.10.0", "cba7924cf526097d2082ceb0ec34e7db6bca2624b8f3867fb3fa89c4cf25d227", [:rebar3], [], "hexpm"},
-  "ex_doc": {:hex, :ex_doc, "0.21.3", "857ec876b35a587c5d9148a2512e952e24c24345552259464b98bfbb883c7b42", [:mix], [{:earmark, "~> 1.4", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "0db1ee8d1547ab4877c5b5dffc6604ef9454e189928d5ba8967d4a58a801f161"},
+  "ex_doc": {:hex, :ex_doc, "0.22.1", "9bb6d51508778193a4ea90fa16eac47f8b67934f33f8271d5e1edec2dc0eee4c", [:mix], [{:earmark, "~> 1.4.0", [hex: :earmark, repo: "hexpm", optional: false]}, {:makeup_elixir, "~> 0.14", [hex: :makeup_elixir, repo: "hexpm", optional: false]}], "hexpm", "d957de1b75cb9f78d3ee17820733dc4460114d8b1e11f7ee4fd6546e69b1db60"},
  "exexec": {:hex, :exexec, "0.2.0", "a6ffc48cba3ac9420891b847e4dc7120692fb8c08c9e82220ebddc0bb8d96103", [:mix], [{:erlexec, "~> 1.10", [hex: :erlexec, repo: "hexpm", optional: false]}], "hexpm"},
-  "jason": {:hex, :jason, "1.2.0", "10043418c42d2493d0ee212d3fddd25d7ffe484380afad769a0a38795938e448", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "116747dbe057794c3a3e4e143b7c8390b29f634e16c78a7f59ba75bfa6852e7f"},
-  "makeup": {:hex, :makeup, "1.0.1", "82f332e461dc6c79dbd82fbe2a9c10d48ed07146f0a478286e590c83c52010b5", [:mix], [{:nimble_parsec, "~> 0.5.0", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "49736fe5b66a08d8575bf5321d716bac5da20c8e6b97714fec2bcd6febcfa1f8"},
-  "makeup_elixir": {:hex, :makeup_elixir, "0.14.0", "cf8b7c66ad1cff4c14679698d532f0b5d45a3968ffbcbfd590339cb57742f1ae", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "d4b316c7222a85bbaa2fd7c6e90e37e953257ad196dc229505137c5e505e9eff"},
-  "nimble_parsec": {:hex, :nimble_parsec, "0.5.3", "def21c10a9ed70ce22754fdeea0810dafd53c2db3219a0cd54cf5526377af1c6", [:mix], [], "hexpm", "589b5af56f4afca65217a1f3eb3fee7e79b09c40c742fddc1c312b3ac0b3399f"},
+  "jason": {:hex, :jason, "1.2.1", "12b22825e22f468c02eb3e4b9985f3d0cb8dc40b9bd704730efa11abd2708c44", [:mix], [{:decimal, "~> 1.0", [hex: :decimal, repo: "hexpm", optional: true]}], "hexpm", "b659b8571deedf60f79c5a608e15414085fa141344e2716fbd6988a084b5f993"},
+  "makeup": {:hex, :makeup, "1.0.3", "e339e2f766d12e7260e6672dd4047405963c5ec99661abdc432e6ec67d29ef95", [:mix], [{:nimble_parsec, "~> 0.5", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "2e9b4996d11832947731f7608fed7ad2f9443011b3b479ae288011265cdd3dad"},
+  "makeup_elixir": {:hex, :makeup_elixir, "0.14.1", "4f0e96847c63c17841d42c08107405a005a2680eb9c7ccadfd757bd31dabccfb", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "f2438b1a80eaec9ede832b5c41cd4f373b38fd7aa33e3b22d9db79e640cbde11"},
+  "mime": {:hex, :mime, "1.3.1", "30ce04ab3175b6ad0bdce0035cba77bba68b813d523d1aac73d9781b4d193cf8", [:mix], [], "hexpm", "6cbe761d6a0ca5a31a0931bf4c63204bceb64538e664a8ecf784a9a6f3b875f1"},
+  "nimble_parsec": {:hex, :nimble_parsec, "0.6.0", "32111b3bf39137144abd7ba1cce0914533b2d16ef35e8abc5ec8be6122944263", [:mix], [], "hexpm", "27eac315a94909d4dc68bc07a4a83e06c8379237c5ea528a9acff4ca1c873c52"},
  "nimble_pool": {:hex, :nimble_pool, "0.1.0", "ffa9d5be27eee2b00b0c634eb649aa27f97b39186fec3c493716c2a33e784ec6", [:mix], [], "hexpm", "343a1eaa620ddcf3430a83f39f2af499fe2370390d4f785cd475b4df5acaf3f9"},
+  "plug": {:hex, :plug, "1.10.3", "c9cebe917637d8db0e759039cc106adca069874e1a9034fd6e3fdd427fd3c283", [:mix], [{:mime, "~> 1.0", [hex: :mime, repo: "hexpm", optional: false]}, {:plug_crypto, "~> 1.1.1 or ~> 1.2", [hex: :plug_crypto, repo: "hexpm", optional: false]}, {:telemetry, "~> 0.4", [hex: :telemetry, repo: "hexpm", optional: false]}], "hexpm", "01f9037a2a1de1d633b5a881101e6a444bcabb1d386ca1e00bb273a1f1d9d939"},
+  "plug_crypto": {:hex, :plug_crypto, "1.1.2", "bdd187572cc26dbd95b87136290425f2b580a116d3fb1f564216918c9730d227", [:mix], [], "hexpm", "6b8b608f895b6ffcfad49c37c7883e8df98ae19c6a28113b02aa1e9c5b22d6b5"},
+  "telemetry": {:hex, :telemetry, "0.4.1", "ae2718484892448a24470e6aa341bc847c3277bfb8d4e9289f7474d752c09c7f", [:rebar3], [], "hexpm", "4738382e36a0a9a2b6e25d67c960e40e1a2c95560b9f936d8e29de8cd858480f"},
 }
--- a/src/libmagic_port.c
+++ b/src/libmagic_port.c
@ -1,5 +1,5 @@
 //
-// The Sorcerer’s Apprentice
+// libmagic_port: The Sorcerer’s Apprentice
 //
 // To use this program, compile it with dynamically linked libmagic, as mirrored
 // at https://github.com/file/file. You may install it with apt-get,
@ -24,12 +24,15 @@
 // Commands are sent to the program STDIN as an erlang term of `{Operation,
 // Argument}`, and response of `{:ok | :error, Response}`.
 //
+// The program may exit with the following exit codes:
+//  - 1 if libmagic handles could not be opened,
+//  - 2 if something went wrong with ei_*,
+//  - 3 if you sent invalid term format,
+//  - 255 if the loop exited unexpectedly.
+//
 // Invalid packets will cause the program to exit (exit code 3). This will
 // happen if your Erlang Term format doesn't match the version the program has
-// been compiled with, or if you send a command too huge.
-//
-// The program may exit with exit code 3 if something went wrong with ei_*
-// functions.
+// been compiled with.
 //
 // Commands:
 // {:reload, _} :: :ready
@ -47,6 +50,7 @@
 #include <libgen.h>
 #include <magic.h>
 #include <stdarg.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@ -55,7 +59,7 @@
 #include <unistd.h>

 #define ERROR_OK 0
-#define ERROR_DB 1
+#define ERROR_MAGIC 1
 #define ERROR_EI 2
 #define ERROR_BAD_TERM 3

@ -78,6 +82,7 @@ magic_t magic_setup(int flags);
 typedef char byte;

 void setup_environment();
+void magic_close_all();
 void magic_open_all();
 int magic_load_all(char *path);
 int process_command(uint16_t len, byte *buf);
@ -93,6 +98,8 @@ static magic_t magic_mime_type;     // MAGIC_MIME_TYPE
 static magic_t magic_mime_encoding; // MAGIC_MIME_ENCODING
 static magic_t magic_type_name;     // MAGIC_NONE

+bool magic_loaded = false;
+
 int main(int argc, char **argv) {
  EI_ENSURE(ei_init());
  setup_environment();
@ -143,6 +150,7 @@ int process_command(uint16_t len, byte *buf) {

  // {:file, path}
  if (strlen(atom) == 4 && strncmp(atom, "file", 4) == 0) {
+    if (magic_loaded) {
      char path[4097];
      ei_get_type(buf, &index, &termtype, &termsize);

@ -160,8 +168,13 @@ int process_command(uint16_t len, byte *buf) {
        error(&result, "badarg");
        return 1;
      }
+    } else {
+      error(&result, "magic_database_not_loaded");
+      return 1;
+    }
    // {:bytes, bytes}
  } else if (strlen(atom) == 5 && strncmp(atom, "bytes", 5) == 0) {
+    if (magic_loaded) {
      int termtype;
      int termsize;
      char bytes[51];
@ -176,6 +189,10 @@ int process_command(uint16_t len, byte *buf) {
        error(&result, "badarg");
        return 1;
      }
+    } else {
+      error(&result, "magic_database_not_loaded");
+      return 1;
+    }
    // {:add_database, path}
  } else if (strlen(atom) == 12 && strncmp(atom, "add_database", 12) == 0) {
    char path[4097];
@ -190,7 +207,8 @@ int process_command(uint16_t len, byte *buf) {
          EI_ENSURE(ei_x_encode_atom(&result, "ok"));
          EI_ENSURE(ei_x_encode_atom(&result, "loaded"));
        } else {
-          exit(ERROR_DB);
+          EI_ENSURE(ei_x_encode_atom(&result, "error"));
+          EI_ENSURE(ei_x_encode_atom(&result, "not_loaded"));
        }
      } else {
        error(&result, "enametoolong");
@ -207,7 +225,8 @@ int process_command(uint16_t len, byte *buf) {
      EI_ENSURE(ei_x_encode_atom(&result, "ok"));
      EI_ENSURE(ei_x_encode_atom(&result, "loaded"));
    } else {
-      exit(ERROR_DB);
+      EI_ENSURE(ei_x_encode_atom(&result, "error"));
+      EI_ENSURE(ei_x_encode_atom(&result, "not_loaded"));
    }
    // {:reload, _}
  } else if (strlen(atom) == 6 && strncmp(atom, "reload", 6) == 0) {
@ -230,25 +249,37 @@ int process_command(uint16_t len, byte *buf) {

 void setup_environment() { opterr = 0; }

-void magic_open_all() {
+void magic_close_all() {
+  magic_loaded = false;
  if (magic_mime_encoding) {
    magic_close(magic_mime_encoding);
+    magic_mime_encoding = NULL;
  }
  if (magic_mime_type) {
    magic_close(magic_mime_type);
+    magic_mime_type = NULL;
  }
  if (magic_type_name) {
    magic_close(magic_type_name);
+    magic_type_name = NULL;
  }
+}
+
+void magic_open_all() {
+  magic_close_all();
  magic_mime_encoding = magic_open(MAGIC_FLAGS_COMMON | MAGIC_MIME_ENCODING);
  magic_mime_type = magic_open(MAGIC_FLAGS_COMMON | MAGIC_MIME_TYPE);
  magic_type_name = magic_open(MAGIC_FLAGS_COMMON | MAGIC_NONE);

+  if (magic_mime_encoding && magic_mime_type && magic_type_name) {
    ei_x_buff ok_buf;
    EI_ENSURE(ei_x_new_with_version(&ok_buf));
    EI_ENSURE(ei_x_encode_atom(&ok_buf, "ready"));
    write_cmd(ok_buf.buff, ok_buf.index);
    EI_ENSURE(ei_x_free(&ok_buf));
+  } else {
+    exit(ERROR_MAGIC);
+  }
 }

 int magic_load_all(char *path) {
@ -263,6 +294,7 @@ int magic_load_all(char *path) {
  if ((res = magic_load(magic_type_name, path)) != 0) {
    return res;
  }
+  magic_loaded = true;
  return 0;
 }

--- a/test/majic/helpers_test.exs
+++ b/test/majic/helpers_test.exs
@ -1,9 +1,14 @@
-defmodule Majic.HelpersTest do
+defmodule Majic.OnceTest do
  use Majic.MagicCase
-  doctest Majic.Helpers
+  doctest Majic.Once

-  test "perform_once" do
+  test "perform" do
    path = absolute_path("Makefile")
-    assert {:ok, %{mime_type: "text/x-makefile"}} = Majic.Helpers.perform_once(path)
+    assert {:ok, %{mime_type: "text/x-makefile"}} = Majic.Once.perform(path)
+  end
+
+  test "Majic.perform" do
+    path = absolute_path("Makefile")
+    assert {:ok, %{mime_type: "text/x-makefile"}} = Majic.perform(path, once: true)
  end
 end
--- a/test/majic/majic_test.exs
+++ b/test/majic/majic_test.exs
@ -11,6 +11,12 @@ defmodule MajicTest do
    assert {:ok, %{mime_type: "text/x-makefile"}} = Majic.Server.perform(pid, path)
  end

+  test "With Majic.perform" do
+    {:ok, pid} = Majic.Server.start_link([])
+    path = absolute_path("Makefile")
+    assert {:ok, %{mime_type: "text/x-makefile"}} = Majic.perform(path, server: pid)
+  end
+
  @tag external: true
  test "Load test local files" do
    {:ok, pid} = Majic.Server.start_link([])
--- a/test/majic/pool_test.exs
+++ b/test/majic/pool_test.exs
@ -12,5 +12,6 @@ defmodule Majic.PoollTest do
    assert {:ok, _} = Majic.Pool.perform(TestPool, absolute_path("Makefile"))
    assert {:ok, _} = Majic.Pool.perform(TestPool, absolute_path("Makefile"))
    assert {:ok, _} = Majic.Pool.perform(TestPool, absolute_path("Makefile"))
+    assert {:ok, _} = Majic.perform(absolute_path("Makefile"), pool: TestPool)
  end
 end
--- a/test/majic/port_test.exs
+++ b/test/majic/port_test.exs
@ -1,4 +1,4 @@
-defmodule Majic.ApprenticeTest do
+defmodule Majic.PortTest do
  use Majic.MagicCase

  @tmp_path "/tmp/testgenmagicx"
@ -7,18 +7,10 @@ defmodule Majic.ApprenticeTest do
  test "sends ready" do
    port = Port.open(Majic.Config.get_port_name(), Majic.Config.get_port_options([]))
    on_exit(fn -> send(port, {self(), :close}) end)
-    assert_ready_and_init_default(port)
+    assert_ready(port)
  end

-  test "stops" do
-    port = Port.open(Majic.Config.get_port_name(), Majic.Config.get_port_options([]))
-    on_exit(fn -> send(port, {self(), :close}) end)
-    assert_ready_and_init_default(port)
-    send(port, {self(), {:command, :erlang.term_to_binary({:stop, :stop})}})
-    assert_receive {^port, {:exit_status, 0}}
-  end
-
-  test "exits with non existent database with an error" do
+  test "errors with non existent database with an error" do
    opts = [:use_stdio, :binary, :exit_status, {:packet, 2}, {:args, []}]
    port = Port.open(Majic.Config.get_port_name(), opts)
    on_exit(fn -> send(port, {self(), :close}) end)
@ -29,7 +21,54 @@ defmodule Majic.ApprenticeTest do
      {self(), {:command, :erlang.term_to_binary({:add_database, "/somewhere/nowhere"})}}
    )

-    assert_receive {^port, {:exit_status, 1}}
+    assert_receive {^port, {:data, data}}
+    assert {:error, :not_loaded} == :erlang.binary_to_term(data)
+  end
+
+  test "loads default database" do
+    opts = [:use_stdio, :binary, :exit_status, {:packet, 2}, {:args, []}]
+    port = Port.open(Majic.Config.get_port_name(), opts)
+    on_exit(fn -> send(port, {self(), :close}) end)
+    assert_ready(port)
+
+    send(
+      port,
+      {self(), {:command, :erlang.term_to_binary({:add_default_database, nil})}}
+    )
+
+    assert_receive {^port, {:data, data}}
+    assert {:ok, :loaded} == :erlang.binary_to_term(data)
+  end
+
+  test "reloads" do
+    opts = [:use_stdio, :binary, :exit_status, {:packet, 2}, {:args, []}]
+    port = Port.open(Majic.Config.get_port_name(), opts)
+    on_exit(fn -> send(port, {self(), :close}) end)
+    assert_ready_and_init_default(port)
+
+    send(port, {self(), {:command, :erlang.term_to_binary({:reload, :reload})}})
+
+    assert_ready(port)
+  end
+
+  test "errors when no database loaded" do
+    opts = [:use_stdio, :binary, :exit_status, {:packet, 2}, {:args, []}]
+    port = Port.open(Majic.Config.get_port_name(), opts)
+    on_exit(fn -> send(port, {self(), :close}) end)
+    assert_ready(port)
+
+    send(port, {self(), {:command, :erlang.term_to_binary({:bytes, "hello world"})}})
+    assert_receive {^port, {:data, data}}
+    assert {:error, :magic_database_not_loaded} = :erlang.binary_to_term(data)
+    refute_receive _
+  end
+
+  test "stops" do
+    port = Port.open(Majic.Config.get_port_name(), Majic.Config.get_port_options([]))
+    on_exit(fn -> send(port, {self(), :close}) end)
+    assert_ready_and_init_default(port)
+    send(port, {self(), {:command, :erlang.term_to_binary({:stop, :stop})}})
+    assert_receive {^port, {:exit_status, 0}}
  end

  describe "port" do
--- a/test/test_helper.exs
+++ b/test/test_helper.exs
@ -1,7 +1,31 @@
 ExUnit.start()

+restore_ulimit =
+  case System.cmd("env", ["sh", "-c", "ulimit -c"]) do
+    {"unlimited\n", 0} ->
+      nil
+
+    {old, 0} ->
+      case System.cmd("env", ["sh", "-c", "ulimit -c unlimited"]) do
+        {_, 0} ->
+          IO.puts("Enabled coredumps with ulimit.")
+          old
+
+        error ->
+          IO.puts("Failed to enable coredumps: #{inspect(error)}")
+      end
+
+    error ->
+      IO.puts("Couldn't use ulimit for coredumps: #{inspect(error)}")
+      nil
+  end
+
 if System.get_env("TEAMCITY_VERSION") do
  ExUnit.configure(formatters: [TeamCityFormatter])
 end

-ExUnit.configure(exclude: [external: true])
+ExUnit.configure(exclude: [external: true], capture_log: true)
+
+if restore_ulimit do
+  System.cmd("env", ["sh", "-c", "ulimit -c #{String.trim(restore_ulimit)}"])
+end