From d4b45615886b9d0d0eb3da8254dbb3ab3f7478f8 Mon Sep 17 00:00:00 2001
From: Mikael Voss <mvs@nyantec.com>
Date: Fri, 29 Nov 2024 20:42:04 +0100
Subject: [PATCH] builders: Determine qemu executable paths at build time

---
 pkgs/build-worker-oci/default.nix   | 5 ++++-
 pkgs/build-worker-oci/entrypoint.sh | 6 ++----
 2 files changed, 6 insertions(+), 5 deletions(-)

diff --git a/pkgs/build-worker-oci/default.nix b/pkgs/build-worker-oci/default.nix
index 06ce68f..040a305 100644
--- a/pkgs/build-worker-oci/default.nix
+++ b/pkgs/build-worker-oci/default.nix
@@ -1,5 +1,6 @@
 # I hate this so much aaa
 {
+  lib,
   callPackage,
   dockerTools,
   openssh,
@@ -95,7 +96,9 @@ dockerTools.buildLayeredImage {
     mkdir -p /var/empty
     mkdir -p /var/log
 
-    cp ${./entrypoint.sh} /entrypoint.sh
+    substitute ${./entrypoint.sh} /entrypoint.sh \
+      --subst-var-by qemu-aarch64 ${lib.getExe' qemu-user "qemu-aarch64"} \
+      --subst-var-by qemu-riscv64 ${lib.getExe' qemu-user "qemu-riscv64"} 
     chmod +x /entrypoint.sh
   '';
 }
diff --git a/pkgs/build-worker-oci/entrypoint.sh b/pkgs/build-worker-oci/entrypoint.sh
index 4bf14fc..4b75186 100644
--- a/pkgs/build-worker-oci/entrypoint.sh
+++ b/pkgs/build-worker-oci/entrypoint.sh
@@ -33,9 +33,7 @@ aarch64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\x
 riscv64_magic='\x7fELF\x02\x01\x01\x00\x00\x00\x00\x00\x00\x00\x00\x00\x02\x00\xf3\x00'
 riscv64_mask='\xff\xff\xff\xff\xff\xff\xff\x00\xff\xff\xff\xff\xff\xff\xff\xff\xfe\xff\xff\xff'
 
-execPath() { readlink -f "$(which "$1")" }
-
-echo ":qemu-aarch64:M::$aarch64_magic:$aarch64_mask:$(execPath qemu-aarch64):POCF" >/proc/sys/fs/binfmt_misc/register
-echo ":qemu-riscv64:M::$riscv64_magic:$riscv64_mask:$(execPath qemu-riscv64):POCF" >/proc/sys/fs/binfmt_misc/register
+echo ":qemu-aarch64:M::$aarch64_magic:$aarch64_mask:@qemu-aarch64@:POCF" >/proc/sys/fs/binfmt_misc/register
+echo ":qemu-riscv64:M::$riscv64_magic:$riscv64_mask:@qemu-riscv64@:POCF" >/proc/sys/fs/binfmt_misc/register
 
 /root/.nix-profile/bin/sshd -D -f /root/sshd_config