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{ lib, pkgs, config, ... }:
with builtins; with lib;
{
imports = [
(mkRenamedOptionModule [ "wsl" "compatibility" "interopPreserveArgvZero" ] [ "wsl" "interop" "preserveArgvZero" ])
];
options.wsl.interop = with types; {
register = mkOption {
type = bool;
default = false; # Use the existing registration by default
description = "Explicitly register the binfmt_misc handler for Windows executables";
};
includePath = mkOption {
type = bool;
default = true;
description = "Include Windows PATH in WSL PATH";
};
preserveArgvZero = mkOption {
type = nullOr bool;
default = null;
description = ''
Register binfmt interpreter for Windows executables with 'preserves argv[0]' flag.
Default (null): autodetect, at some performance cost.
To avoid the performance cost, set this to true for WSL Preview 0.58 and up,
or to false for any older versions, including pre-Microsoft Store and Windows 10.
'';
};
};
config =
let
cfg = config.wsl.interop;
in
mkIf config.wsl.enable {
boot.binfmt.registrations = mkIf cfg.register {
WSLInterop =
let
compat = cfg.preserveArgvZero;
# WSL Preview 0.58 and up registers the /init binfmt interp for Windows executable
# with the "preserve argv[0]" flag, so if you run `./foo.exe`, the interp gets invoked
# as `/init foo.exe ./foo.exe`.
# argv[0] --^ ^-- actual path
#
# Older versions expect to be called without the argv[0] bit, simply as `/init ./foo.exe`.
#
# We detect that by running `/init /known-not-existing-path.exe` and checking the exit code:
# the new style interp expects at least two arguments, so exits with exit code 1,
# presumably meaning "parsing error"; the old style interp attempts to actually run
# the executable, fails to find it, and exits with 255.
compatWrapper = pkgs.writeShellScript "nixos-wsl-binfmt-hack" ''
/init /nixos-wsl-does-not-exist.exe
[ $? -eq 255 ] && shift
exec /init "$@"
'';
# use the autodetect hack if unset, otherwise call /init directly
interpreter = if compat == null then compatWrapper else "/init";
# enable for the wrapper and autodetect hack
preserveArgvZero = if compat == false then false else true;
in
{
magicOrExtension = "MZ";
fixBinary = true;
wrapInterpreterInShell = false;
inherit interpreter preserveArgvZero;
};
};
warnings =
let
registrations = config.boot.binfmt.registrations;
in
optional (!(registrations ? WSLInterop) && (length (attrNames config.boot.binfmt.registrations)) != 0) "Having any binfmt registrations without re-registering WSLInterop (wsl.interop.register) will break running .exe files from WSL2";
};
}
|
