Support dnf5: libdnf5 actions plugin hook and needs-restarting subcommand

Makefile

@@ -23,6 +23,16 @@ CONF_DIR=/etc/smart-restart-conf.d
 
 HOOK_ACTION=install.action
 HOOK_ACTION_TEMPLATE=$(HOOK_ACTION).in
+
+# dnf5 loads post-transaction hooks through the libdnf5 actions plugin:
+# *.actions files under /etc/dnf/libdnf5-plugins/actions.d with a
+# "HOOK:PKG_FILTER:DIRECTION:OPTIONS:CMD" line format.
+ifeq ($(pkg_manager),dnf5)
+HOOK_DIR=/etc/dnf/libdnf5-plugins/actions.d
+HOOK_ACTION=smart-restart.actions
+HOOK_ACTION_TEMPLATE=install.actions.in
+endif
+
 DENYLIST_CONF_FILE=default-denylist
 MAN_FILE=smart-restart.1
 MAN_FILE_LOCATION=/usr/share/man/man1

bin/smart-restart.sh

@@ -22,6 +22,16 @@ readonly POST_RESTART=("$CONF_PATH"/*post-restart)
 shopt -u nullglob
 
 SYSCTL_COMMAND="${SYSCTL_COMMAND:-systemctl}"
+# dnf5-only systems implement needs-restarting as a dnf5 subcommand (a
+# compat shim may still provide /usr/bin/needs-restarting). Detect the
+# active stack by what /usr/bin/dnf resolves to, so a side-installed dnf5
+# on a dnf4 system does not flip the tool. When this script runs from the
+# libdnf5 actions plugin hook, the calling dnf process still holds the
+# system repository lock, so the inner dnf5 must skip file locking to
+# avoid deadlocking on its parent transaction.
+if [[ -z "${NEEDS_RESTARTING_COMMAND:-}" ]] && [[ "$(readlink -f /usr/bin/dnf 2>/dev/null)" == *dnf5 ]]; then
+    NEEDS_RESTARTING_COMMAND="dnf5 needs-restarting --skip-file-locks"
+fi
 NEEDS_RESTARTING_COMMAND="${NEEDS_RESTARTING_COMMAND:-/usr/bin/needs-restarting}"
 
 IS_TESTING=${IS_TESTING:-}

conf/install.actions.in

@@ -0,0 +1,4 @@
+# Run smart-restart after every transaction that installs or upgrades
+# packages. The libdnf5 actions plugin deduplicates identical expanded
+# commands, so this runs once per transaction.
+post_transaction:*:#COMMAND#::sh #PREFIX#/smart-restart.sh

smart-restart.spec

@@ -17,11 +17,22 @@ License:        Apache 2.0
 Requires:       yum-utils 
 Requires:       yum-plugin-post-transaction-actions
 %define         _plugin_path yum/post-actions/
+%define         _hook_file install.action
 %define         pkg_manager yum
+%elif 0%{?amzn} >= 2027
+# dnf5-only. needs-restarting is the dnf5 subcommand from dnf5-plugins,
+# and the post-transaction hook runs through the libdnf5 actions plugin
+# instead of dnf4's post-transaction-actions plugin.
+Requires:       dnf5-plugins
+Requires:       libdnf5-plugin-actions
+%define         _plugin_path dnf/libdnf5-plugins/actions.d/
+%define         _hook_file smart-restart.actions
+%define         pkg_manager dnf5
 %else
 Requires:       dnf-utils
 Requires:       dnf-plugin-post-transaction-actions
 %define         _plugin_path dnf/plugins/post-transaction-actions.d/
+%define         _hook_file install.action
 %define         pkg_manager dnf
 %endif
 
@@ -42,7 +53,7 @@ make DEST_DIR=$RPM_BUILD_ROOT pkg_manager=%{pkg_manager} PREFIX=%{_bindir} insta
 %files
 %defattr(-,root,root,-)
 %{_bindir}/%{name}.sh
-%config %{_sysconfdir}/%{_plugin_path}/install.action
+%config %{_sysconfdir}/%{_plugin_path}/%{_hook_file}
 %config %{_sysconfdir}/smart-restart-conf.d/default-denylist
 %doc %{_mandir}/man1/smart-restart.1*