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/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