feat: Create a systemd unit to create opt links on boot (#380)

This creates a systemd unit file that will execute on boot and create
symlinks in `/var/opt/` for every directory that exists in
`/usr/lib/opt/`. This removes the need for users to manually create
these links to get programs working like the Brave browser.

modules/rpm-ostree/bluebuild-optfix.service

@@ -0,0 +1,11 @@
+[Unit]
+Description=Create symbolic links for directories in /usr/lib/opt/ to /var/opt/
+After=multi-user.target
+
+[Service]
+Type=oneshot
+ExecStart=/usr/libexec/bluebuild/optfix.sh
+RemainAfterExit=no
+
+[Install]
+WantedBy=default.target

modules/rpm-ostree/optfix.sh

@@ -0,0 +1,27 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+SOURCE_DIR="/usr/lib/opt/"
+TARGET_DIR="/var/opt/"
+
+# Ensure the target directory exists
+mkdir -p "$TARGET_DIR"
+
+# Loop through directories in the source directory
+for dir in "$SOURCE_DIR"*/; do
+  if [ -d "$dir" ]; then
+    # Get the base name of the directory
+    dir_name=$(basename "$dir")
+
+    # Check if the symlink already exists in the target directory
+    if [ -L "$TARGET_DIR/$dir_name" ]; then
+      echo "Symlink already exists for $dir_name, skipping."
+      continue
+    fi
+
+    # Create the symlink
+    ln -s "$dir" "$TARGET_DIR/$dir_name"
+    echo "Created symlink for $dir_name"
+  fi
+done

modules/rpm-ostree/rpm-ostree.sh

@@ -42,16 +42,32 @@ fi
 # Create symlinks to fix packages that create directories in /opt
 get_json_array OPTFIX 'try .["optfix"][]' "$1"
 if [[ ${#OPTFIX[@]} -gt 0 ]]; then
+    LIB_EXEC_DIR="/usr/libexec/bluebuild"
+    SYSTEMD_DIR="/etc/systemd/system"
+    MODULE_DIR="/tmp/modules/rpm-ostree"
+
+    if ! [ -x "${LIB_EXEC_DIR}/optfix.sh" ]; then
+        mkdir -p "${LIB_EXEC_DIR}"
+        cp "${MODULE_DIR}/optfix.sh" "${LIB_EXEC_DIR}/"
+        chmod +x "${LIB_EXEC_DIR}/optfix.sh"
+    fi
+
+    if ! [ -f "${SYSTEMD_DIR}/bluebuild-optfix.service" ]; then
+        cp "${MODULE_DIR}/bluebuild-optfix.service" "${SYSTEMD_DIR}/"
+        systemctl enable bluebuild-optfix.service
+    fi
+
     echo "Creating symlinks to fix packages that install to /opt"
     # Create symlink for /opt to /var/opt since it is not created in the image yet
     mkdir -p "/var/opt"
-    ln -s "/var/opt"  "/opt"
+    ln -fs "/var/opt"  "/opt"
+
     # Create symlinks for each directory specified in recipe.yml
     for OPTPKG in "${OPTFIX[@]}"; do
         OPTPKG="${OPTPKG%\"}"
         OPTPKG="${OPTPKG#\"}"
         mkdir -p "/usr/lib/opt/${OPTPKG}"
-        ln -s "../../usr/lib/opt/${OPTPKG}" "/var/opt/${OPTPKG}"
+        ln -fs "/usr/lib/opt/${OPTPKG}" "/var/opt/${OPTPKG}"
         echo "Created symlinks for ${OPTPKG}"
     done
 fi