games: Move FMOD fixing from Bastion to setup hook

Thanks to @layus for pointing out that there is at least one other game
(Epistory) which has the same FMOD issue as Bastion has.

So I decided to move this into a setup hook that automatically discovers
whether it's the affected FMOD version and NOPs out the calls to
system().

In summary: If another game is affected, all that's needed now is to add
fixFmodHook to nativeBuildInputs.

Signed-off-by: aszlig <aszlig@nix.build>
Cc: @layus

1 files changed, 3 insertions, 49 deletions

diff --git a/pkgs/games/humblebundle/bastion.nix b/pkgs/games/humblebundle/bastion.nix
index 3a4af115..207dd105 100644
--- a/pkgs/games/humblebundle/bastion.nix
+++ b/pkgs/games/humblebundle/bastion.nix
@@ -1,5 +1,5 @@
-{ lib, stdenv, buildGame, fetchHumbleBundle, makeWrapper, unzip, imagemagick
-, mono, SDL2, SDL2_image, openal, libvorbis, libGL
+{ lib, stdenv, buildGame, fixFmodHook, fetchHumbleBundle, makeWrapper
+, unzip, imagemagick, mono, SDL2, SDL2_image, openal, libvorbis, libGL
 }:
 
 buildGame rec {
@@ -15,7 +15,7 @@ buildGame rec {
 
   unpackCmd = "${unzip}/bin/unzip -qq \"$curSrc\" 'data/*' || :";
 
-  nativeBuildInputs = [ makeWrapper imagemagick ];
+  nativeBuildInputs = [ makeWrapper imagemagick fixFmodHook ];
 
   libDir =
     if stdenv.system == "i686-linux" then "lib"
@@ -58,39 +58,6 @@ buildGame rec {
     patchelf --remove-needed libsteam_api.so "$libDir/libSteamWrapper.so"
     patchelf --add-needed libSteamStub.so "$libDir/libSteamWrapper.so"
 
-    # FMOD Ex tries to run /bin/sh -c 'pulseaudio --check > /dev/null 2>&1', so
-    # we need to prevent this by replacing the system() call with a successful
-    # return value (0). If someone doesn't have or want to have PulseAudio,
-    # FMOD Ex still falls back to ALSA if it can't load libpulse-simple.so.
-    if [ "$libDir" = lib64 ]; then
-      addr="$(objdump -d lib64/libfmodex.so | sed -n -e '
-        /callq.*system@plt/s/^ *\([^:]\+\).*/\1/p
-      ')"
-
-      # This is quite easy, just replace the system() call with XOR EAX so we
-      # get a return value of 0 and pad the rest with NOP.
-      offset=$(("0x$addr"))
-      ( printf '\x31\xc0'     # XOR the EAX register
-        printf '\x90\x90\x90' # Fill with NOPs
-      ) | dd of="$libDir/libfmodex.so" obs=1 seek=$offset count=5 conv=notrunc
-    else
-      relocSystem="$(readelf -r lib/libfmodex.so | sed -n -e '
-        /system@/s/^0*\([^ ]\+\).*/\1/p
-      ')"
-      addr="$(objdump -d lib/libfmodex.so | sed -n -e '
-        /call *'"$relocSystem"' /s/^ *\([^:]\+\).*/\1/p
-      ')"
-
-      # For the 32 bit library it's not so easy as the 4 bytes coming after the
-      # CALL opcode will be replaced by the dynamic linker, so we just XOR the
-      # EAX register with the relocation address and replace the TEST opcode
-      # afterwards.
-      offset=$(("0x$addr"))
-      ( printf '\x35\xfc\xff\xff\xff' # XOR EAX with the relocation address
-        printf '\x39\xc0'             # CMP EAX, EAX
-      ) | dd of="$libDir/libfmodex.so" obs=1 seek=$offset conv=notrunc
-    fi
-
     # For the Desktop icon
     convert Bastion.bmp Bastion.png
   '';
@@ -127,18 +94,5 @@ buildGame rec {
     EOF
   '';
 
-  # Add all of the libraries in $runtimeDependencies to the FMOD Ex library,
-  # because it tries to dlopen() libpulse-simple and libasound.so and we don't
-  # have a main ELF binary where we could add that search path.
-  postPhases = [ "fixFModex" ];
-  fixFModex = ''
-    rpath="$(patchelf --print-rpath "$out/libexec/bastion/libfmodex.so")"
-    for dep in $runtimeDependencies; do
-      rpath="$rpath''${rpath:+:}$dep/lib"
-    done
-    echo "setting RPATH for libfmodex to: $rpath" >&2
-    patchelf --set-rpath "$rpath" "$out/libexec/bastion/libfmodex.so"
-  '';
-
   sandbox.paths.required = [ "$XDG_DATA_HOME/Bastion" ];
 }