From ebaedb5377dcc5e6aca28ef666871e424dd39938 Mon Sep 17 00:00:00 2001
From: Bignaux Ronan <ronan@aimao.org>
Date: Tue, 3 Mar 2020 01:40:57 +0100
Subject: [PATCH] appimage: refactoring extractType2 to avoid use of appimage
 packer

---
 pkgs/build-support/appimage/default.nix | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/pkgs/build-support/appimage/default.nix b/pkgs/build-support/appimage/default.nix
index c871df787b7..f4ccd038f76 100644
--- a/pkgs/build-support/appimage/default.nix
+++ b/pkgs/build-support/appimage/default.nix
@@ -1,4 +1,4 @@
-{ stdenv, libarchive, patchelf, zlib, buildFHSUserEnv, writeScript }:
+{ stdenv, libarchive, radare2, jq, buildFHSUserEnv, squashfsTools, writeScript }:
 
 rec {
   # Both extraction functions could be unified, but then
@@ -19,15 +19,16 @@ rec {
     name = "${name}-extracted";
     inherit src;
 
-    nativeBuildInputs = [ patchelf ];
+    nativeBuildInputs = [ radare2 jq squashfsTools ];
     buildCommand = ''
       install $src ./appimage
-      patchelf \
-        --set-interpreter ${stdenv.cc.bintools.dynamicLinker} \
-        --replace-needed libz.so.1 ${zlib}/lib/libz.so.1 \
-        ./appimage
 
-      ./appimage --appimage-extract
+      # multiarch offset one-liner using same method as AppImage
+      # see https://gist.github.com/probonopd/a490ba3401b5ef7b881d5e603fa20c93
+      offset=$(r2 ./appimage -nn -Nqc "pfj.elf_header @ 0" |\
+        jq 'map({(.name): .value}) | add | .shoff + (.shnum * .shentsize)')
+
+      unsquashfs -o $offset ./appimage
 
       cp -rv squashfs-root $out
     '';