From cda13d55491f0c2f70c24c263ee689eef32f96bd Mon Sep 17 00:00:00 2001
From: Vinz Spring <vinzs@amazon.de>
Date: Wed, 19 Aug 2026 13:56:34 +0000
Subject: [PATCH] Support dnf5: libdnf5 actions plugin hook and
 needs-restarting subcommand

dnf5-only systems (e.g. Amazon Linux 2027) drop the dnf4
post-transaction-actions plugin, leaving smart-restart uninstallable
and its hook mechanism gone. Add first-class dnf5 support:

- Makefile: pkg_manager=dnf5 installs the hook through the libdnf5
  actions plugin (*.actions file under
  /etc/dnf/libdnf5-plugins/actions.d) from a new
  conf/install.actions.in template
- smart-restart.sh: when dnf5 is present, default
  NEEDS_RESTARTING_COMMAND to 'dnf5 needs-restarting --skip-file-locks'.
  The actions plugin runs the hook synchronously inside the dnf
  transaction, which still holds the system repository lock, so the
  inner dnf5 must skip file locking or it deadlocks on its own parent
  (verified live: the hook child sat in 'Waiting for a lock on the
  system repository' naming its ancestor until killed)
- spec: on amzn >= 2027, require dnf5-plugins and
  libdnf5-plugin-actions, package the actions.d hook file

yum and dnf4 behavior is unchanged; the existing test suite passes and
'make install' output is identical for the default and yum modes.

Note: dnf5 < a3dcdacdc93c has a needs-restarting D-Bus regression
(rpm-software-management/dnf5#2562) that breaks service detection in
hook contexts regardless of this change; distros need that fix for the
hook to be fully functional.
---
 Makefile                | 10 ++++++++++
 bin/smart-restart.sh    | 10 ++++++++++
 conf/install.actions.in |  4 ++++
 smart-restart.spec      | 13 ++++++++++++-
 4 files changed, 36 insertions(+), 1 deletion(-)
 create mode 100644 conf/install.actions.in

diff --git a/Makefile b/Makefile
index 6f4aba5..0b40f6f 100644
--- a/Makefile
+++ b/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
diff --git a/bin/smart-restart.sh b/bin/smart-restart.sh
index 8fb5d21..9e35962 100755
--- a/bin/smart-restart.sh
+++ b/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:-}
diff --git a/conf/install.actions.in b/conf/install.actions.in
new file mode 100644
index 0000000..f20183b
--- /dev/null
+++ b/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
diff --git a/smart-restart.spec b/smart-restart.spec
index e3275fb..068b6e1 100644
--- a/smart-restart.spec
+++ b/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*