support metamodule, remove built-in overlayfs mount

Co-authored-by: weishu <twsxtd@gmail.com>
Co-authored-by: YuKongA <70465933+YuKongA@users.noreply.github.com>
Co-authored-by: Ylarod <me@ylarod.cn>

userspace/meta-overlayfs/metamodule/customize.sh

@@ -0,0 +1,67 @@
+#!/system/bin/sh
+
+ui_print "- Detecting device architecture..."
+
+# Detect architecture using ro.product.cpu.abi
+ABI=$(grep_get_prop ro.product.cpu.abi)
+ui_print "- Detected ABI: $ABI"
+
+# Select the correct binary based on architecture
+case "$ABI" in
+    arm64-v8a)
+        ARCH_BINARY="meta-overlayfs-aarch64"
+        REMOVE_BINARY="meta-overlayfs-x86_64"
+        ui_print "- Selected architecture: ARM64"
+        ;;
+    x86_64)
+        ARCH_BINARY="meta-overlayfs-x86_64"
+        REMOVE_BINARY="meta-overlayfs-aarch64"
+        ui_print "- Selected architecture: x86_64"
+        ;;
+    *)
+        abort "! Unsupported architecture: $ABI"
+        ;;
+esac
+
+# Verify the selected binary exists
+if [ ! -f "$MODPATH/$ARCH_BINARY" ]; then
+    abort "! Binary not found: $ARCH_BINARY"
+fi
+
+ui_print "- Installing $ARCH_BINARY as meta-overlayfs"
+
+# Rename the selected binary to the generic name
+mv "$MODPATH/$ARCH_BINARY" "$MODPATH/meta-overlayfs" || abort "! Failed to rename binary"
+
+# Remove the unused binary
+rm -f "$MODPATH/$REMOVE_BINARY"
+
+# Ensure the binary is executable
+chmod 755 "$MODPATH/meta-overlayfs" || abort "! Failed to set permissions"
+
+ui_print "- Architecture-specific binary installed successfully"
+
+# Create ext4 image for module content storage
+IMG_FILE="$MODPATH/modules.img"
+IMG_SIZE_MB=2048
+EXISTING_IMG="/data/adb/modules/$MODID/modules.img"
+
+if [ -f "$EXISTING_IMG" ]; then
+    ui_print "- Reusing modules image from previous install"
+    "$MODPATH/meta-overlayfs" xcp "$EXISTING_IMG" "$IMG_FILE" || \
+        abort "! Failed to copy existing modules image"
+else
+    ui_print "- Creating 2GB ext4 image for module storage"
+
+    # Create sparse file (2GB logical size, 0 bytes actual)
+    truncate -s ${IMG_SIZE_MB}M "$IMG_FILE" || \
+        abort "! Failed to create image file"
+
+    # Format as ext4 with small journal (8MB) for safety with minimal overhead
+    /system/bin/mke2fs -t ext4 -J size=8 -F "$IMG_FILE" >/dev/null 2>&1 || \
+        abort "! Failed to format ext4 image"
+
+    ui_print "- Image created successfully (sparse file)"
+fi
+
+ui_print "- Installation complete"

userspace/meta-overlayfs/metamodule/metainstall.sh

@@ -0,0 +1,99 @@
+#!/system/bin/sh
+############################################
+# meta-overlayfs metainstall.sh
+# Module installation hook for ext4 image support
+############################################
+
+# Constants
+IMG_FILE="/data/adb/metamodule/modules.img"
+MNT_DIR="/data/adb/metamodule/mnt"
+
+# Ensure ext4 image is mounted
+ensure_image_mounted() {
+    if ! mountpoint -q "$MNT_DIR" 2>/dev/null; then
+        ui_print "- Mounting modules image"
+        mkdir -p "$MNT_DIR"
+        mount -t ext4 -o loop,rw,noatime "$IMG_FILE" "$MNT_DIR" || {
+            abort "! Failed to mount modules image"
+        }
+        ui_print "- Image mounted successfully"
+    else
+        ui_print "- Image already mounted"
+    fi
+}
+
+# Determine whether this module should be moved into the ext4 image.
+# We only relocate payloads that expose system/ overlays and do not opt out via skip_mount.
+module_requires_overlay_move() {
+    if [ -f "$MODPATH/skip_mount" ]; then
+        ui_print "- skip_mount flag detected; keeping files under /data/adb/modules"
+        return 1
+    fi
+
+    if [ ! -d "$MODPATH/system" ]; then
+        ui_print "- No system/ directory detected; keeping files under /data/adb/modules"
+        return 1
+    fi
+
+    return 0
+}
+
+# Copy SELinux contexts from src tree to destination by mirroring each entry.
+copy_selinux_contexts() {
+    command -v chcon >/dev/null 2>&1 || return 0
+
+    SRC="$1"
+    DST="$2"
+
+    if [ -z "$SRC" ] || [ -z "$DST" ] || [ ! -e "$SRC" ] || [ ! -e "$DST" ]; then
+        return 0
+    fi
+
+    chcon --reference="$SRC" "$DST" 2>/dev/null || true
+
+    find "$SRC" -print | while IFS= read -r PATH_SRC; do
+        if [ "$PATH_SRC" = "$SRC" ]; then
+            continue
+        fi
+        REL_PATH="${PATH_SRC#"${SRC}/"}"
+        PATH_DST="$DST/$REL_PATH"
+        if [ -e "$PATH_DST" ] || [ -L "$PATH_DST" ]; then
+            chcon --reference="$PATH_SRC" "$PATH_DST" 2>/dev/null || true
+        fi
+    done
+}
+
+# Post-installation: move partition directories to ext4 image
+post_install_to_image() {
+    ui_print "- Copying module content to image"
+
+    set_perm_recursive "$MNT_DIR" 0 0 0755 0644
+
+    MOD_IMG_DIR="$MNT_DIR/$MODID"
+    mkdir -p "$MOD_IMG_DIR"
+
+    # Move all partition directories
+    for partition in system vendor product system_ext odm oem; do
+        if [ -d "$MODPATH/$partition" ]; then
+            ui_print "- Copying $partition/"
+            cp -af "$MODPATH/$partition" "$MOD_IMG_DIR/" || {
+                ui_print "! Warning: Failed to move $partition"
+                continue
+            }
+            copy_selinux_contexts "$MODPATH/$partition" "$MOD_IMG_DIR/$partition"
+        fi
+    done
+}
+
+ui_print "- Using meta-overlayfs metainstall"
+
+install_module
+
+if module_requires_overlay_move; then
+    ensure_image_mounted
+    post_install_to_image
+else
+    ui_print "- Skipping move to modules image"
+fi
+
+ui_print "- Installation complete"

userspace/meta-overlayfs/metamodule/metamount.sh

@@ -0,0 +1,65 @@
+#!/system/bin/sh
+# meta-overlayfs Module Mount Handler
+# This script is the entry point for dual-directory module mounting
+
+MODDIR="${0%/*}"
+IMG_FILE="$MODDIR/modules.img"
+MNT_DIR="$MODDIR/mnt"
+
+# Log function
+log() {
+    echo "[meta-overlayfs] $1"
+}
+
+log "Starting module mount process"
+
+# Ensure ext4 image is mounted
+if ! mountpoint -q "$MNT_DIR" 2>/dev/null; then
+    log "Image not mounted, mounting now..."
+
+    # Check if image file exists
+    if [ ! -f "$IMG_FILE" ]; then
+        log "ERROR: Image file not found at $IMG_FILE"
+        exit 1
+    fi
+
+    # Create mount point
+    mkdir -p "$MNT_DIR"
+
+    # Mount the ext4 image
+    mount -t ext4 -o loop,rw,noatime "$IMG_FILE" "$MNT_DIR" || {
+        log "ERROR: Failed to mount image"
+        exit 1
+    }
+    log "Image mounted successfully at $MNT_DIR"
+else
+    log "Image already mounted at $MNT_DIR"
+fi
+
+# Binary path (architecture-specific binary selected during installation)
+BINARY="$MODDIR/meta-overlayfs"
+
+if [ ! -f "$BINARY" ]; then
+    log "ERROR: Binary not found: $BINARY"
+    exit 1
+fi
+
+# Set dual-directory environment variables
+export MODULE_METADATA_DIR="/data/adb/modules"
+export MODULE_CONTENT_DIR="$MNT_DIR"
+
+log "Metadata directory: $MODULE_METADATA_DIR"
+log "Content directory: $MODULE_CONTENT_DIR"
+log "Executing $BINARY"
+
+# Execute the mount binary
+"$BINARY"
+EXIT_CODE=$?
+
+if [ $EXIT_CODE -ne 0 ]; then
+    log "Mount failed with exit code $EXIT_CODE"
+    exit $EXIT_CODE
+fi
+
+log "Mount completed successfully"
+exit 0

userspace/meta-overlayfs/metamodule/metauninstall.sh

@@ -0,0 +1,35 @@
+#!/system/bin/sh
+############################################
+# mm-overlayfs metauninstall.sh
+# Module uninstallation hook for ext4 image cleanup
+############################################
+
+# Constants
+MNT_DIR="/data/adb/metamodule/mnt"
+
+if [ -z "$MODULE_ID" ]; then
+    echo "! Error: MODULE_ID not provided"
+    exit 1
+fi
+
+echo "- Cleaning up module content from image: $MODULE_ID"
+
+# Check if image is mounted
+if ! mountpoint -q "$MNT_DIR" 2>/dev/null; then
+    echo "! Warning: Image not mounted, skipping cleanup"
+    exit 0
+fi
+
+# Remove module content from image
+MOD_IMG_DIR="$MNT_DIR/$MODULE_ID"
+if [ -d "$MOD_IMG_DIR" ]; then
+    echo "  Removing $MOD_IMG_DIR"
+    rm -rf "$MOD_IMG_DIR" || {
+        echo "! Warning: Failed to remove module content from image"
+    }
+    echo "- Module content removed from image"
+else
+    echo "- No module content found in image, skipping"
+fi
+
+exit 0

userspace/meta-overlayfs/metamodule/module.prop

@@ -0,0 +1,8 @@
+id=meta-overlayfs
+metamodule=1
+name=OverlayFS MetaModule
+version=1.0.0
+versionCode=1
+author=KernelSU Developers
+description=An implementation of a metamodule using OverlayFS for KernelSU
+updateJson=https://raw.githubusercontent.com/tiann/KernelSU/main/userspace/meta-overlayfs/update.json

userspace/meta-overlayfs/metamodule/uninstall.sh

@@ -0,0 +1,24 @@
+#!/system/bin/sh
+############################################
+# mm-overlayfs uninstall.sh
+# Cleanup script for metamodule removal
+############################################
+
+MODDIR="${0%/*}"
+MNT_DIR="$MODDIR/mnt"
+
+echo "- Uninstalling metamodule..."
+
+# Unmount the ext4 image if mounted
+if mountpoint -q "$MNT_DIR" 2>/dev/null; then
+    echo "- Unmounting image..."
+    umount "$MNT_DIR" 2>/dev/null || {
+        echo "- Warning: Failed to unmount cleanly"
+        umount -l "$MNT_DIR" 2>/dev/null
+    }
+    echo "- Image unmounted"
+fi
+
+echo "- Uninstall complete"
+
+exit 0