general: automate recovery build

README.md

@@ -8,9 +8,13 @@ recoveries and ROMs for the Galaxy Tab Active SM-T365.
 ## Recovery
 
 ```
-nix-shell shell.nix --run ./build_recovery.sh
+./build_twrp.sh
 ```
 
+This builds the recovery inside the nix-shell FHS environment (shell.nix);
+the script re-executes itself there, so it works from the host even though
+`nix-shell --run` is broken by the `exec android-env` shellHook.
+
 # Device information
 
 | Basic             | Spec sheet                             |
@@ -33,3 +37,11 @@ nix-shell shell.nix --run ./build_recovery.sh
 | Rear camera       | 3.1 Mpx                                |
 | Front camera      | 1.2 Mpx                                |
 | Similar devices   | milletlte, matisselte, motorola_thea   |
+
+# Links to device trees, manifests, etc.
+
+- https://github.com/matteo0026/android_device_samsung_rubenslte
+- https://git.cfpi-fpsi.eu/rubenslte/twrp_device_samsung_rubenslte
+- https://git.cfpi-fpsi.eu/rubenslte/android_kernel_samsung_rubenslte
+- https://github.com/matteo0026/twrp_device_samsung_milletlte
+- https://github.com/matteo0026/twrp_device_samsung_matisselte

build_twrp.sh

@@ -1,11 +1,22 @@
 #!/usr/bin/env bash
+# Build a TWRP recovery image for Samsung Galaxy Tab Active (SM-T365, rubenslte).
+# Must run inside the nix-shell FHS environment (shell.nix): if invoked from the
+# host, it re-executes itself inside that environment via its stdin pipe.
 set -euo pipefail
 
-export ALLOW_NINJA_ENV=true USE_CCACHE=1 LD_LIBRARY_PATH=/usr/lib:/usr/lib32 LC_ALL=C LANG=C LC_CTYPE=C
+SCRIPT="$(realpath "$(dirname "${BASH_SOURCE[0]}")")"
 
-cd "$(realpath "$(dirname "${BASH_SOURCE[0]}")")"
-SCRIPT="$PWD"
+if [ -z "${RUBENSLTE_BUILD_IN_ENV:-}" ]; then
+    echo "[*] Entering nix-shell FHS build environment ..."
+    cd "$SCRIPT"
+    printf '\nexport RUBENSLTE_BUILD_IN_ENV=1\nbash "%s/build_twrp.sh"\n' "$SCRIPT" \
+        | nix-shell shell.nix
+    exit $?
+fi
 
+export LC_ALL=C LANG=C LC_CTYPE=C
+
+cd "$SCRIPT"
 mkdir -p twrp-build
 cd twrp-build
 
@@ -13,30 +24,32 @@ if [ ! -d .repo ]; then
     repo init --depth 1 -u https://github.com/minimal-manifest-twrp/platform_manifest_twrp_omni.git -b twrp-5.1
 fi
 
-repo sync -j$(nproc)
+repo sync -c -j$(nproc)
 
+# Device tree (gitea mirror of this repo)
 if [ ! -d device/samsung/rubenslte ]; then
     git clone --depth 1 https://git.cfpi-fpsi.eu/rubenslte/twrp_device_samsung_rubenslte device/samsung/rubenslte
 fi
 
+# Kernel built from source (gitea mirror of Samsung msm8226 stock tree)
+if [ ! -d kernel/samsung/rubenslte ]; then
+    git clone --depth 1 https://git.cfpi-fpsi.eu/rubenslte/android_kernel_samsung_rubenslte kernel/samsung/rubenslte
+fi
+
 for p in "$SCRIPT"/patches/*.patch; do
     patch -p1 -s < "$p" 2>/dev/null || true
 done
 
-export AR="$(command -v ar)"
-export CC="$(command -v gcc)"
-export CXX="$(command -v g++)"
-
-HOST_TOOLCHAIN="prebuilts/gcc/linux-x86/host/x86_64-linux-glibc2.11-4.6/bin"
-if [ ! -f "$HOST_TOOLCHAIN/x86_64-linux-ar" ]; then
-    mkdir -p "$HOST_TOOLCHAIN"
-    for tool in ar gcc g++; do
-        src="$(command -v $tool)"
-        if [ -n "$src" ]; then
-            ln -sf "$src" "$HOST_TOOLCHAIN/x86_64-linux-$tool"
-        fi
-    done
+# arm-eabi-4.8 cross toolchain (AOSP prebuilt, plain gcc host binary)
+ARM_EABI_DIR="prebuilts/gcc/linux-x86/arm/arm-eabi-4.8"
+if [ ! -x "$ARM_EABI_DIR/bin/arm-eabi-gcc" ]; then
+    echo "[*] Downloading arm-eabi-4.8 prebuilt toolchain ..."
+    mkdir -p "$ARM_EABI_DIR"
+    curl -L --fail \
+        "https://android.googlesource.com/platform/prebuilts/gcc/linux-x86/arm/arm-eabi-4.8/+archive/refs/tags/android-5.1.1_r38.tar.gz" \
+        | tar -xz -C "$ARM_EABI_DIR"
 fi
+export PATH="$PWD/$ARM_EABI_DIR/bin:$PATH"
 
 export TOP="$PWD"
 set +u
@@ -45,5 +58,5 @@ lunch omni_rubenslte-userdebug
 set -u
 mka recoveryimage
 
-cp out/target/product/rubenslte/recovery.img "$SCRIPT"
+cp out/target/product/rubenslte/recovery.img "$SCRIPT/"
 echo "Done: $SCRIPT/recovery.img"

shell.nix

@@ -48,5 +48,10 @@ let
 in pkgs.stdenv.mkDerivation {
   name = "android-env-shell";
   nativeBuildInputs = [ fhs ];
-  shellHook = "exec android-env";
+  shellHook = ''
+    if [ -n "$BASH_EXECUTION_STRING" ]; then
+      exec android-env -c "$BASH_EXECUTION_STRING"
+    fi
+    exec android-env
+  '';
 }