From e95e00f879e24c0f087763ec471fb9bdf9a8f92b Mon Sep 17 00:00:00 2001
From: Serge Schneider <serge@raspberrypi.com>
Date: Mon, 13 May 2024 15:24:21 +0100
Subject: [PATCH 1/2] Set a default IMG_NAME

This also adds the 'ARCH' environment variable, which will help reduce the delta between master and arm64 branches.
---
 README.md | 2 +-
 build.sh  | 9 +++------
 2 files changed, 4 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index c48e708..c584825 100644
--- a/README.md
+++ b/README.md
@@ -52,7 +52,7 @@ environment variables.
 
 The following environment variables are supported:
 
- * `IMG_NAME` **required** (Default: unset)
+ * `IMG_NAME` (Default: raspios-$RELEASE-$ARCH, for example: "raspios-bookworm-armhf")
 
    The name of the image to build with the current stage directories. Use this
    variable to set the root name of your OS, eg `IMG_NAME=Frobulator`.
diff --git a/build.sh b/build.sh
index 054b3f5..3cb10e7 100755
--- a/build.sh
+++ b/build.sh
@@ -167,10 +167,9 @@ export PI_GEN=${PI_GEN:-pi-gen}
 export PI_GEN_REPO=${PI_GEN_REPO:-https://github.com/RPi-Distro/pi-gen}
 export PI_GEN_RELEASE=${PI_GEN_RELEASE:-Raspberry Pi reference}
 
-if [ -z "${IMG_NAME}" ]; then
-	echo "IMG_NAME not set" 1>&2
-	exit 1
-fi
+export ARCH=armhf
+export RELEASE=${RELEASE:-bookworm} # Don't forget to update stage0/prerun.sh
+export IMG_NAME="${IMG_NAME:-raspios-$RELEASE-$ARCH}"
 
 export USE_QEMU="${USE_QEMU:-0}"
 export IMG_DATE="${IMG_DATE:-"$(date +%Y-%m-%d)"}"
@@ -198,7 +197,6 @@ export TARGET_HOSTNAME=${TARGET_HOSTNAME:-raspberrypi}
 export FIRST_USER_NAME=${FIRST_USER_NAME:-pi}
 export FIRST_USER_PASS
 export DISABLE_FIRST_BOOT_USER_RENAME=${DISABLE_FIRST_BOOT_USER_RENAME:-0}
-export RELEASE=${RELEASE:-bookworm} # Don't forget to update stage0/prerun.sh
 export WPA_COUNTRY
 export ENABLE_SSH="${ENABLE_SSH:-0}"
 export PUBKEY_ONLY_SSH="${PUBKEY_ONLY_SSH:-0}"
@@ -215,7 +213,6 @@ export GIT_HASH=${GIT_HASH:-"$(git rev-parse HEAD)"}
 export PUBKEY_SSH_FIRST_USER
 
 export CLEAN
-export IMG_NAME
 export APT_PROXY
 
 export STAGE

From d87f764fcbc2e9bdbfd407d2cbf9b5faf5600df1 Mon Sep 17 00:00:00 2001
From: Serge Schneider <serge@raspberrypi.com>
Date: Mon, 13 May 2024 15:54:28 +0100
Subject: [PATCH 2/2] build.sh: Warn user of unsupported build environment
 architecture and fail early if binfmt_misc isn't working as expected

---
 Dockerfile | 4 ++--
 README.md  | 2 +-
 build.sh   | 9 +++++++++
 depends    | 1 +
 4 files changed, 13 insertions(+), 3 deletions(-)

diff --git a/Dockerfile b/Dockerfile
index 673f756..0e6d86d 100644
--- a/Dockerfile
+++ b/Dockerfile
@@ -7,8 +7,8 @@ RUN apt-get -y update && \
     apt-get -y install --no-install-recommends \
         git vim parted \
         quilt coreutils qemu-user-static debootstrap zerofree zip dosfstools \
-        libarchive-tools libcap2-bin rsync grep udev xz-utils curl xxd file kmod bc\
-        binfmt-support ca-certificates fdisk gpg pigz\
+        libarchive-tools libcap2-bin rsync grep udev xz-utils curl xxd file kmod bc \
+        binfmt-support ca-certificates fdisk gpg pigz arch-test \
     && rm -rf /var/lib/apt/lists/*
 
 COPY . /pi-gen/
diff --git a/README.md b/README.md
index c584825..279baaa 100644
--- a/README.md
+++ b/README.md
@@ -19,7 +19,7 @@ To install the required dependencies for `pi-gen` you should run:
 ```bash
 apt-get install coreutils quilt parted qemu-user-static debootstrap zerofree zip \
 dosfstools libarchive-tools libcap2-bin grep rsync xz-utils file git curl bc \
-gpg pigz xxd
+gpg pigz xxd arch-test
 ```
 
 The file `depends` contains a list of tools needed.  The format of this
diff --git a/build.sh b/build.sh
index 3cb10e7..d094eee 100755
--- a/build.sh
+++ b/build.sh
@@ -244,6 +244,15 @@ fi
 
 dependencies_check "${BASE_DIR}/depends"
 
+echo "Checking native $ARCH executable support..."
+if ! arch-test -n "$ARCH"; then
+	echo "WARNING: Only a native build environment is supported. Checking emulated support..."
+	if ! arch-test "$ARCH"; then
+		echo "No fallback mechanism found. Ensure your OS has binfmt_misc support enabled and configured."
+		exit 1
+	fi
+fi
+
 #check username is valid
 if [[ ! "$FIRST_USER_NAME" =~ ^[a-z][-a-z0-9_]*$ ]]; then
 	echo "Invalid FIRST_USER_NAME: $FIRST_USER_NAME"
diff --git a/depends b/depends
index 10fcdd4..acbb5cd 100644
--- a/depends
+++ b/depends
@@ -19,3 +19,4 @@ lsmod:kmod
 bc
 gpg
 pigz
+arch-test