Compatability of exqlite/Sqlite3, Escript and WSL2?

kevinlang · August 8, 2021, 4:11pm

Hey,

The root error is:

    (stdlib 3.15.1) filename.erl:454: :filename.join({:error, :bad_name}, 'sqlite3_nif')
    (exqlite 0.6.1) lib/exqlite/sqlite3_nif.ex:14: Exqlite.Sqlite3NIF.load_nifs/0

Which comes from the line of code where we load our NIF:

  def load_nifs() do
    path = :filename.join(:code.priv_dir(:exqlite), 'sqlite3_nif')
    :erlang.load_nif(path, 0)
  end

It looks like this is because the priv/ directory is not supproted in escript.

github.com/elixir-lang/elixir

escript: wrong path for NIF libraries

opened 10:33AM - 13 Nov 16 UTC

closed 10:54AM - 13 Nov 16 UTC

pmontrasio

Note:Unresolved

### Environment * Elixir version (elixir -v): ``` Erlang/OTP 19 [erts-8.1…] [source] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] Elixir 1.3.4 ``` * Operating system: ``` $ lsb_release -a No LSB modules are available. Distributor ID: Raspbian Description: Raspbian GNU/Linux 8.0 (jessie) Release: 8.0 Codename: jessie ``` To provide some context, this is a Raspeberry PI 3 with an external WiFi card. The program I'm working on uses [:wierl](https://github.com/msantos/wierl) and [:epcap](https://github.com/msantos/epcap) to put that WiFi card in monitor mode and read packets. The ```:epcap``` module includes a shared library which is built as ```deps/procket/priv/procket.so``` (btw, the built in WiFi card doesn't support monitor mode, that's why I'm using an external one.) ### Current behavior The project directory is ```sensor``` and ```mix escript.build``` builds the app as ```sensor```. It worked until I added the dependency from ```:epcap```. Then ``` $ ./sensor wlan1 11:22:03.317 [warn] The on_load function for module procket returned {:error, {:load_failed, 'Failed to load NIF library: \'/home/me/sensor/sensor/../priv/procket.so: cannot open shared object file: Not a directory\''}} ** (UndefinedFunctionError) function :procket.socket/3 is undefined (module :procket is not available) :procket.socket(:inet, :dgram, 0) src/wierl_config.erl:175: :wierl_config.down/1 (sensor) lib/antenna.ex:4: Antenna.enter_monitor_mode/1 (sensor) lib/sensor.ex:13: Sensor.start/1 (elixir) lib/kernel/cli.ex:76: anonymous fn/3 in Kernel.CLI.exec_fun/2 ``` Note that the path ```/home/me/sensor/sensor/../priv/procket.so``` is obviously wrong because of two reasons: 1) The second occurrence of ```sensor``` is actually a file (the app) and not a directory, and the path is wrong even if I manually create a ```priv``` dir under ```/home/me/sensor``` 2) The shared library is in ```deps/procket/priv/procket.so``` There is another shared library in ```deps/epcap/priv/epcap_drv.so``` but it probably failed first on loading ```procket.so```. Running the application as a mix task or from ```iex -S mix``` works. ### Expected behavior Escript should load the shared library from its path ```/home/me/sensor/deps/procket/priv/procket.so```

It looks like NIFs in general cannot work in escript. Bummer.