Fix chroot-based build setup

Author: TheAssassin

BUILD.md

@@ -64,3 +64,13 @@ To specify commands that should be run, use the established `--` to distinguish
 # fish
 > env ARCH=<arch> scripts/create-build-container.sh -u $(id -u):(id -g) -- bash some-script.sh
 ```
+
+## chroot-based environment
+
+The chroot-based environment is designed for people who really do not want to use containers and/or run on systems that do not support such an environment (e.g., FreeBSD).
+
+To run a build, use the following command:
+
+```sh
+> env ARCHITECTURE=<arch> chroot/chroot_build.sh
+```

chroot/build.sh

@@ -8,7 +8,7 @@ if ! command -v apk; then
 fi
 
 apk update
-apk add alpine-sdk util-linux strace file autoconf automake libtool xz
+apk add alpine-sdk util-linux strace file autoconf automake libtool xz bash
 
 # Build static libfuse3 with patch for https://github.com/AppImage/type2-runtime/issues/10
 apk add eudev-dev gettext-dev linux-headers meson # From https://git.alpinelinux.org/aports/tree/main/fuse3/APKBUILD

chroot/chroot_build.sh

@@ -1,13 +1,29 @@
-#!/bin/sh
+#! /bin/bash
 
 set -ex
 
+# build in a temporary directory
+# this makes sure that subsequent runs do not influence each other
+# also makes cleaning up easier: just dump the entire directory
+tempdir="$(mktemp -d)"
+
+# need to memorize the repository root directory's path so that we can copy files from it
+repo_root_dir="$(readlink -f "$(dirname "${BASH_SOURCE[0]}")")"/..
+
+# cleanup takes care of unmounting and removing all downloaded files
+cleanup() {
+    sudo umount "$tempdir"/miniroot/{dev,proc,sys}
+    sudo rm -rf "$tempdir"
+}
+trap cleanup EXIT
+
+cd "$tempdir"
+
 #############################################
 # Download and extract minimal Alpine system
 #############################################
 
 wget "http://dl-cdn.alpinelinux.org/alpine/v3.17/releases/${ARCHITECTURE}/alpine-minirootfs-3.17.2-${ARCHITECTURE}.tar.gz"
-sudo rm -rf ./miniroot  true # Clean up from previous runs
 mkdir -p ./miniroot
 cd ./miniroot
 sudo tar xf ../alpine-minirootfs-*-"${ARCHITECTURE}".tar.gz
@@ -17,8 +33,8 @@ cd -
 # Prepare chroot
 #############################################
 
-sudo cp -r ./src miniroot/src
-sudo cp -r ./patches miniroot/patches
+sudo cp -r "$repo_root_dir"/src miniroot/src
+sudo cp -r "$repo_root_dir"/patches miniroot/patches
 
 sudo mount -o bind /dev miniroot/dev
 sudo mount -t proc none miniroot/proc
@@ -31,33 +47,27 @@ sudo cp -p /etc/resolv.conf miniroot/etc/
 
 if [ "$ARCHITECTURE" = "x86" ] || [ "$ARCHITECTURE" = "x86_64" ]; then
     echo "Architecture is x86 or x86_64, hence not using qemu-arm-static"
-    sudo cp build.sh miniroot/build.sh && sudo chroot miniroot /bin/sh -ex /build.sh
+    sudo cp "$repo_root_dir"/chroot/build.sh miniroot/build.sh && sudo chroot miniroot /bin/sh -ex /build.sh
 elif [ "$ARCHITECTURE" = "aarch64" ] ; then
     echo "Architecture is aarch64, hence using qemu-aarch64-static"
     sudo cp "$(which qemu-aarch64-static)" miniroot/usr/bin
-    sudo cp build.sh miniroot/build.sh && sudo chroot miniroot qemu-aarch64-static /bin/sh -ex /build.sh
+    sudo cp "$repo_root_dir"/chroot/build.sh miniroot/build.sh && sudo chroot miniroot qemu-aarch64-static /bin/sh -ex /build.sh
 elif [ "$ARCHITECTURE" = "armhf" ] ; then
     echo "Architecture is armhf, hence using qemu-arm-static"
     sudo cp "$(which qemu-arm-static)" miniroot/usr/bin
-    sudo cp build.sh miniroot/build.sh && sudo chroot miniroot qemu-arm-static /bin/sh -ex /build.sh
+    sudo cp "$repo_root_dir"/chroot/build.sh miniroot/build.sh && sudo chroot miniroot qemu-arm-static /bin/sh -ex /build.sh
 else
     echo "Edit chroot_build.sh to support this architecture as well, it should be easy"
     exit 1
 fi
 
-#############################################
-# Clean up chroot
-#############################################
-
-sudo umount miniroot/proc miniroot/sys miniroot/dev
-
 #############################################
 # Copy build artefacts out
 #############################################
 
 # Use the same architecture names as https://github.com/AppImage/AppImageKit/releases/
 if [ "$ARCHITECTURE" = "x86" ] ; then ARCHITECTURE=i686 ; fi
 
-mkdir out/
-sudo find miniroot/ -type f -executable -name 'runtime-fuse3' -exec cp {} "out/runtime-${ARCHITECTURE}" \;
-sudo rm -rf miniroot/
+cd "$repo_root_dir"
+mkdir -p ./out/
+sudo find "$tempdir"/miniroot/ -type f -executable -name 'runtime-fuse3' -exec cp {} "out/runtime-${ARCHITECTURE}" \;

scripts/install-dependencies.sh

@@ -2,18 +2,33 @@
 
 set -euo pipefail
 
+# use a temporary directory to download the files
+tmpdir="$(mktemp -d)"
+
+# clean it up whenever the script exits
+cleanup() {
+    echo "Cleaning up $tmpdir"
+    rm -rf "$tmpdir"
+}
+trap cleanup EXIT
+
+# store current file's path
+# needed to determine the path of the patches
+this_dir="$(readlink -f "$(dirname "${BASH_SOURCE[0]}")")"
+
+cd "$tmpdir"
+
 wget https://github.com/libfuse/libfuse/releases/download/fuse-3.15.0/fuse-3.15.0.tar.xz
 echo "70589cfd5e1cff7ccd6ac91c86c01be340b227285c5e200baa284e401eea2ca0  fuse-3.15.0.tar.xz" | sha256sum -c -
 tar xf fuse-3.*.tar.xz
 pushd fuse-3*/
-patch -p1 < /tmp/patches/libfuse/mount.c.diff
+patch -p1 < "$this_dir"/../patches/libfuse/mount.c.diff
 mkdir build
 cd build
 meson setup --prefix=/usr ..
 meson configure --default-library static
 ninja -v install
 popd
-rm -r fuse-*
 
 # Minimize binary size
 export CFLAGS="-ffunction-sections -fdata-sections -Os"
@@ -28,4 +43,3 @@ make -j"$(nproc)"
 make install
 /usr/bin/install -c -m 644 ./*.h '/usr/local/include/squashfuse'
 popd
-rm -r e51978c* squashfuse*