Re: [PATCH v2 3/8] util: add APIs for more systemd notifications

12 Feb 2025

On Wed, Feb 12, 2025 at 15:46:41 +0000, Daniel P. Berrangé wrote:
...
We have a way to notify systemd when we're done starting the daemon.
Systemd supports many more notifications, however, and many of them
are quite relevant to our needs:
https://www.freedesktop.org/software/systemd/man/latest/sd_notify.html
This renames the existing notification API to better reflect its
semantics, and adds new APIs for reporting
* Initiation of config file reload
 * Initiation of daemon shutdown process
 * Adhoc progress status messages
 * Request to extend service shutdown timeout
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
 src/libvirt_private.syms |  6 +++++-
 src/rpc/virnetdaemon.c   |  2 +-
 src/util/virsystemd.c    | 44 +++++++++++++++++++++++++++++++++++++---
 src/util/virsystemd.h    |  6 +++++-
 4 files changed, 52 insertions(+), 6 deletions(-)

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 6888f6b599..4eca252b2a 100644
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -3531,7 +3531,11 @@ virSystemdHasResolved;
 virSystemdHasResolvedResetCachedValue;
 virSystemdMakeScopeName;
 virSystemdMakeSliceName;
-virSystemdNotifyStartup;
+virSystemdNotifyExtendTimeout;
+virSystemdNotifyReady;
+virSystemdNotifyReload;
+virSystemdNotifyStatus;
+virSystemdNotifyStopping;
 virSystemdResolvedRegisterNameServer;
 virSystemdTerminateMachine;
diff --git a/src/rpc/virnetdaemon.c b/src/rpc/virnetdaemon.c
index f647cf60ba..e6bdfe0f88 100644
--- a/src/rpc/virnetdaemon.c
+++ b/src/rpc/virnetdaemon.c
@@ -753,7 +753,7 @@ virNetDaemonRun(virNetDaemon *dmn)
/* We are accepting connections now. Notify systemd
      * so it can start dependent services. */
-    virSystemdNotifyStartup();
+    virSystemdNotifyReady();
VIR_DEBUG("dmn=%p quit=%d", dmn, dmn->quit);
     while (!dmn->finished) {
diff --git a/src/util/virsystemd.c b/src/util/virsystemd.c
index d46e5f74fc..bbcf77a41f 100644
--- a/src/util/virsystemd.c
+++ b/src/util/virsystemd.c
@@ -624,12 +624,11 @@ int virSystemdTerminateMachine(const char *name)
     return 0;
 }
-void
-virSystemdNotifyStartup(void)
+static void
+virSystemdNotify(const char *msg)
 {
 #ifndef WIN32
     const char *path;
-    const char *msg = "READY=1";
     int fd;
     struct sockaddr_un un = {
         .sun_family = AF_UNIX,
@@ -644,6 +643,8 @@ virSystemdNotifyStartup(void)
         .msg_iovlen = 1,
     };
+    VIR_DEBUG("Notify '%s'", msg);
+
     if (!(path = getenv("NOTIFY_SOCKET"))) {
         VIR_DEBUG("Skipping systemd notify, not requested");
         return;
@@ -674,6 +675,43 @@ virSystemdNotifyStartup(void)
 #endif /* !WIN32 */
 }
+void virSystemdNotifyReady(void)
+{
+    virSystemdNotify("READY=1");
+}
+
+void virSystemdNotifyReload(void)
+{
+    gint64 now = g_get_monotonic_time();
+    g_autofree char *msg = g_strdup_printf(
+        "RELOADING=1\nMONOTONIC_USEC=%lld", (long long int)now);
+    virSystemdNotify(msg);
+}
+
+void virSystemdNotifyStopping(void)
+{
+    virSystemdNotify("STOPPING=1");
+}
+
+void virSystemdNotifyExtendTimeout(int secs)
+{
+    g_autofree char *msg = g_strdup_printf("EXTEND_TIMEOUT_USEC=%llu",
+                                           secs * 1000ull * 1000ul);
'ull' in the second 1000

Reviewed-by: Peter Krempa <pkrempa@redhat.com>

    