fex: add initial package tests

pkgs/by-name/fe/fex/check-home.patch

@@ -0,0 +1,25 @@
+diff --git a/Source/Common/Config.cpp b/Source/Common/Config.cpp
+index 093e11682..fd8143570 100644
+--- a/Source/Common/Config.cpp
++++ b/Source/Common/Config.cpp
+@@ -423,17 +423,17 @@ const char* GetHomeDirectory() {
+   const char* HomeDir = getenv("HOME");
+
+   // Try to get home directory from uid
+-  if (!HomeDir) {
++  if (!HomeDir || !FHU::Filesystem::Exists(HomeDir)) {
+     HomeDir = FindUserHomeThroughUID();
+   }
+
+   // try the PWD
+-  if (!HomeDir) {
++  if (!HomeDir || !FHU::Filesystem::Exists(HomeDir)) {
+     HomeDir = getenv("PWD");
+   }
+
+   // Still doesn't exit? You get local
+-  if (!HomeDir) {
++  if (!HomeDir || !FHU::Filesystem::Exists(HomeDir)) {
+     HomeDir = ".";
+   }
+

pkgs/by-name/fe/fex/cross-includes.patch

@@ -0,0 +1,21 @@
+diff --git a/Scripts/StructPackVerifier.py b/Scripts/StructPackVerifier.py
+index 4716e7976..47a2ef9d9 100755
+--- a/Scripts/StructPackVerifier.py
++++ b/Scripts/StructPackVerifier.py
+@@ -656,14 +656,14 @@ def main():
+         BaseArgs.append(sys.argv[ArgIndex])
+
+     args_x86_32 = [
+-        "-I/usr/i686-linux-gnu/include",
++        "-I@i686Libs@/include",
+         "-O2",
+         "-m32",
+         "--target=i686-linux-unknown",
+     ]
+
+     args_x86_64 = [
+-        "-I/usr/x86_64-linux-gnu/include",
++        "-I@x86_64Libs@/include",
+         "-O2",
+         "--target=x86_64-linux-unknown",
+         "-D_M_X86_64",

pkgs/by-name/fe/fex/package.nix

@@ -2,16 +2,18 @@
   fetchFromGitHub,
   lib,
   llvmPackages,
+  pkgsCross,
+  replaceVars,
   cmake,
   ninja,
   pkg-config,
-  git,
+  gitMinimal,
   qt5,
   python3,
-  python3Packages,
+  nasm,
 }:
 
-llvmPackages.stdenv.mkDerivation rec {
+llvmPackages.stdenv.mkDerivation (finalAttrs: rec {
   pname = "fex";
   version = "2410";
 
@@ -23,15 +25,34 @@ llvmPackages.stdenv.mkDerivation rec {
     fetchSubmodules = true;
   };
 
+  patches = [
+    # These aren't strictly needed.
+    #
+    # This is a workaround to get FEX working within Nix's build sandbox: FEX's
+    # tests will break without it, but you can fix that with `export HOME=$PWD`.
+    #
+    # TODO: upstream this one.
+    ./check-home.patch
+    # This is a workaround to get FEX working with NixOS's slightly weird binfmt
+    # infrastructure.
+    ./realpath.patch
+  ] ++ lib.optional finalAttrs.finalPackage.doCheck (replaceVars ./cross-includes.patch {
+    i686Libs = pkgsCross.gnu32.stdenv.cc.libc_dev;
+    x86_64Libs = pkgsCross.gnu64.stdenv.cc.libc_dev;
+  });
+
   nativeBuildInputs = [
     cmake
     ninja
     pkg-config
-    git
+    gitMinimal
     qt5.wrapQtAppsHook
-    python3
-    python3Packages.setuptools
     llvmPackages.bintools
+
+   (python3.withPackages (pythonPackages: with pythonPackages; [
+    setuptools
+    libclang
+   ]))
   ];
 
   buildInputs = with qt5; [
@@ -45,15 +66,73 @@ llvmPackages.stdenv.mkDerivation rec {
     "-DCMAKE_BUILD_TYPE=Release"
     "-DUSE_LINKER=lld"
     "-DENABLE_LTO=True"
-    "-DBUILD_TESTS=False"
     "-DENABLE_ASSERTIONS=False"
+    (lib.cmakeBool "BUILD_TESTS" finalAttrs.finalPackage.doCheck)
+  ];
+
+  strictDeps = true;
+
+  doCheck = true;
+
+  nativeCheckInputs = [
+    nasm
+    llvmPackages.libcxx
+  ];
+
+  checkInputs = [
+    llvmPackages.libcxx
   ];
 
+  preCheck = ''
+    find \
+      ../External/fex-posixtest-bins/conformance \
+      ../External/fex-gvisor-tests-bins \
+      ../External/fex-gcc-target-tests-bins/64 \
+      -type f -executable \
+      -exec patchelf \
+        --set-interpreter ${pkgsCross.gnu64.stdenv.cc.libc}/lib/ld-linux-x86-64.so.2 \
+        '{}' '+'
+    find ../External/fex-gcc-target-tests-bins/32 -type f -executable \
+      -exec patchelf \
+        --set-interpreter ${pkgsCross.gnu32.stdenv.cc.libc}/lib/ld-linux.so.2 \
+        '{}' '+'
+
+    find ../External/fex-gvisor-tests-bins -type f -executable \
+      -exec patchelf --add-rpath ${pkgsCross.gnu64.gcc.cc.lib}/lib '{}' '+'
+
+    # These all seem to fail due to the build sandbox.
+    echo -n '
+    conformance-interfaces-sched_setparam-26-1.test
+    conformance-interfaces-sigqueue-12-1.test
+    conformance-interfaces-sigqueue-3-1.test
+    ' >> ../unittests/POSIX/Known_Failures
+
+    echo -n '
+    dev_test
+    getcpu_host_test
+    getcpu_test
+    lseek_test
+    tuntap_test
+    write_test
+    ' >> ../unittests/gvisor-tests/Known_Failures
+
+    # For some reason this test fails in darwin.linux-builder, and passes in a UTM
+    # VM; paper over the difference by disabling it.
+    echo 'write_test' >> ../unittests/gvisor-tests/Disabled_Tests
+  '';
+
+  # Avoid wrapping anything other than FEXConfig, since the wrapped executables
+  # don't seem to work when registered as binfmts.
+  dontWrapQtApps = true;
+  preFixup = ''
+    wrapQtApp $out/bin/FEXConfig
+  '';
+
   meta = {
     description = "A fast usermode x86 and x86-64 emulator for Arm64 Linux";
     homepage = "https://fex-emu.com/";
     platforms = [ "aarch64-linux" ];
     license = lib.licenses.mit;
     maintainers = with lib.maintainers; [ andre4ik3 ];
   };
-}
+})

pkgs/by-name/fe/fex/realpath.patch

@@ -0,0 +1,19 @@
+diff --git a/Source/Common/FEXServerClient.cpp b/Source/Common/FEXServerClient.cpp
+index 424ecf0a0..501bcbac1 100644
+--- a/Source/Common/FEXServerClient.cpp
++++ b/Source/Common/FEXServerClient.cpp
+@@ -209,7 +209,13 @@ int ConnectToAndStartServer(char* InterpreterPath) {
+       return -1;
+     }
+
+-    fextl::string FEXServerPath = FHU::Filesystem::ParentPath(InterpreterPath) + "/FEXServer";
++    char RealInterpreterPathBuf[PATH_MAX];
++    char *RealInterpreterPath = realpath(InterpreterPath, RealInterpreterPathBuf);
++    if (!RealInterpreterPath) {
++      LogMan::Msg::EFmt("realpath failed");
++      return -1;
++    }
++    fextl::string FEXServerPath = FHU::Filesystem::ParentPath(RealInterpreterPath) + "/FEXServer";
+     // Check if a local FEXServer next to FEXInterpreter exists
+     // If it does then it takes priority over the installed one
+     if (!FHU::Filesystem::Exists(FEXServerPath)) {