admin: add 'daemon-shutdown' command

The daemons are wired up to shutdown in responsible to UNIX process
signals, as well as in response to login1 dbus signals, or loss of
desktop session. The latter two options can optionally preserve state
(ie running VMs).

In non-systemd environments, as well as for testing, it would be useful
to have a way to trigger shutdown with state preservation more directly.

Thus a new admin protocol API is introduced

  virAdmConnectDaemonShutdown

which will trigger a daemon shutdown, and preserve running VMs if the
VIR_DAEMON_SHUTDOWN_PRESERVE flag is set.

It has a corresponding 'virt-admin daemon-shutdown [--preserve]' command
binding.

Reviewed-by: Peter Krempa <pkrempa@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

docs/manpages/virt-admin.rst

@@ -326,6 +326,19 @@ Sets the daemon timeout to the value of '--timeout' argument. Use ``--timeout 0`
 to disable auto-shutdown of the daemon.
 
 
+daemon-shutdown
+---------------
+
+**Syntax:**
+
+::
+
+   daemon-shutdown [--preserve]
+
+Instruct the daemon to exit gracefully. If the ``--preserve`` flag is given,
+it will save state in the same manner that would be done on a host OS shutdown
+(privileged daemons) or a login session quit (unprivileged daemons).
+
 SERVER COMMANDS
 ===============
 

include/libvirt/libvirt-admin.h

@@ -484,6 +484,19 @@ int virAdmConnectSetDaemonTimeout(virAdmConnectPtr conn,
                                   unsigned int timeout,
                                   unsigned int flags);
 
+/**
+ * virAdmConnectDaemonShutdownFlags:
+ *
+ * Since: 11.2.0
+ */
+typedef enum {
+    /* Preserve state before shutting down daemon (Since: 11.2.0) */
+    VIR_DAEMON_SHUTDOWN_PRESERVE = (1 << 0),
+} virAdmConnectDaemonShutdownFlags;
+
+int virAdmConnectDaemonShutdown(virAdmConnectPtr conn,
+                                unsigned int flags);
+
 # ifdef __cplusplus
 }
 # endif

src/admin/admin_protocol.x

@@ -219,6 +219,10 @@ struct admin_connect_set_daemon_timeout_args {
     unsigned int flags;
 };
 
+struct admin_connect_daemon_shutdown_args {
+    unsigned int flags;
+};
+
 /* Define the program number, protocol version and procedure numbers here. */
 const ADMIN_PROGRAM = 0x06900690;
 const ADMIN_PROTOCOL_VERSION = 1;
@@ -334,5 +338,10 @@ enum admin_procedure {
     /**
      * @generate: both
      */
-    ADMIN_PROC_CONNECT_SET_DAEMON_TIMEOUT = 19
+    ADMIN_PROC_CONNECT_SET_DAEMON_TIMEOUT = 19,
+
+    /**
+     * @generate: both
+     */
+    ADMIN_PROC_CONNECT_DAEMON_SHUTDOWN = 20
 };

src/admin/admin_server_dispatch.c

@@ -474,6 +474,19 @@ adminConnectSetDaemonTimeout(virNetDaemon *dmn,
     return virNetDaemonAutoShutdown(dmn, timeout);
 }
 
+static int
+adminConnectDaemonShutdown(virNetDaemon *dmn,
+                           unsigned int flags)
+{
+    virCheckFlags(VIR_DAEMON_SHUTDOWN_PRESERVE, -1);
+
+    if (flags & VIR_DAEMON_SHUTDOWN_PRESERVE)
+        virNetDaemonStop(dmn);
+
+    virNetDaemonQuit(dmn);
+
+    return 0;
+}
 
 static int
 adminDispatchConnectGetLoggingOutputs(virNetServer *server G_GNUC_UNUSED,

src/admin/libvirt-admin.c

@@ -1357,3 +1357,36 @@ virAdmConnectSetDaemonTimeout(virAdmConnectPtr conn,
 
     return ret;
 }
+
+
+/**
+ * virAdmConnectDaemonShutdown:
+ * @conn: pointer to an active admin connection
+ * @flags: optional extra falgs
+ *
+ * Trigger shutdown of the daemon, if @flags includes
+ * VIR_DAEMON_SHUTDOWN_PRESERVE then state will be
+ * preserved before shutting down
+ *
+ * Returns 0 on success, -1 on error.
+ *
+ * Since: 11.2.0
+ */
+int
+virAdmConnectDaemonShutdown(virAdmConnectPtr conn,
+                            unsigned int flags)
+{
+    int ret;
+
+    VIR_DEBUG("conn=%p, flags=0x%x", conn, flags);
+
+    virResetLastError();
+    virCheckAdmConnectReturn(conn, -1);
+
+    if ((ret = remoteAdminConnectDaemonShutdown(conn, flags)) < 0) {
+        virDispatchError(NULL);
+        return -1;
+    }
+
+    return ret;
+}

src/admin/libvirt_admin_public.syms

@@ -53,3 +53,8 @@ LIBVIRT_ADMIN_8.6.0 {
     global:
         virAdmConnectSetDaemonTimeout;
 } LIBVIRT_ADMIN_3.0.0;
+
+LIBVIRT_ADMIN_11.2.0 {
+    global:
+        virAdmConnectDaemonShutdown;
+} LIBVIRT_ADMIN_8.6.0;

src/admin_protocol-structs

@@ -148,6 +148,9 @@ struct admin_connect_set_daemon_timeout_args {
         u_int                      timeout;
         u_int                      flags;
 };
+struct admin_connect_daemon_shutdown_args {
+        u_int                      flags;
+};
 enum admin_procedure {
         ADMIN_PROC_CONNECT_OPEN = 1,
         ADMIN_PROC_CONNECT_CLOSE = 2,
@@ -168,4 +171,5 @@ enum admin_procedure {
         ADMIN_PROC_CONNECT_SET_LOGGING_FILTERS = 17,
         ADMIN_PROC_SERVER_UPDATE_TLS_FILES = 18,
         ADMIN_PROC_CONNECT_SET_DAEMON_TIMEOUT = 19,
+        ADMIN_PROC_CONNECT_DAEMON_SHUTDOWN = 20,
 };

tools/virt-admin.c

@@ -1077,6 +1077,41 @@ cmdDaemonTimeout(vshControl *ctl, const vshCmd *cmd)
 }
 
 
+/* --------------------------
+ * Command daemon-shutdown
+ * --------------------------
+ */
+static const vshCmdInfo info_daemon_shutdown = {
+    .help = N_("stop the daemon"),
+    .desc = N_("stop the daemon"),
+};
+
+static const vshCmdOptDef opts_daemon_shutdown[] = {
+    {.name = "preserve",
+     .type = VSH_OT_BOOL,
+     .required = false,
+     .positional = false,
+     .help = N_("preserve state before shutting down"),
+    },
+    {.name = NULL}
+};
+
+static bool
+cmdDaemonShutdown(vshControl *ctl, const vshCmd *cmd)
+{
+    vshAdmControl *priv = ctl->privData;
+    unsigned int flags = 0;
+
+    if (vshCommandOptBool(cmd, "preserve"))
+        flags |= VIR_DAEMON_SHUTDOWN_PRESERVE;
+
+    if (virAdmConnectDaemonShutdown(priv->conn, flags) < 0)
+        return false;
+
+    return true;
+}
+
+
 static void *
 vshAdmConnectionHandler(vshControl *ctl)
 {
@@ -1469,6 +1504,12 @@ static const vshCmdDef managementCmds[] = {
      .info = &info_daemon_timeout,
      .flags = 0
     },
+    {.name = "daemon-shutdown",
+     .handler = cmdDaemonShutdown,
+     .opts = opts_daemon_shutdown,
+     .info = &info_daemon_shutdown,
+     .flags = 0
+    },
     {.name = NULL}
 };