From: Debian DNS Team <team+dns@tracker.debian.org>
Date: Wed, 25 Jan 2023 15:51:06 +0100
Subject: Add-support-for-reporting-status-via-sd_notify

---
 bin/named/Makefile.am |  8 +++++++-
 bin/named/server.c    | 44 +++++++++++++++++++++++++++++++++++++++++---
 configure.ac          | 20 ++++++++++++++++++++
 3 files changed, 68 insertions(+), 4 deletions(-)

diff --git a/bin/named/Makefile.am b/bin/named/Makefile.am
index 57a023b..38045f0 100644
--- a/bin/named/Makefile.am
+++ b/bin/named/Makefile.am
@@ -14,6 +14,7 @@ AM_CPPFLAGS +=				\
 	$(MAXMINDDB_CFLAGS)		\
 	$(DNSTAP_CFLAGS)		\
 	$(LIBUV_CFLAGS)			\
+	$(LIBSYSTEMD_CFLAGS)		\
 	$(ZLIB_CFLAGS)
 
 if HAVE_JSON_C
@@ -109,7 +110,7 @@ named_LDADD =					\
 	$(MAXMINDDB_LIBS)			\
 	$(DNSTAP_LIBS)				\
 	$(LIBUV_LIBS)				\
-	$(LIBXML2_LIBS)				\
+	$(LIBSYSTEMD_LIBS)			\
 	$(ZLIB_LIBS)
 
 if HAVE_JSON_C
@@ -121,3 +122,8 @@ if HAVE_LIBNGHTTP2
 named_LDADD +=					\
 	$(LIBNGHTTP2_LIBS)
 endif HAVE_LIBNGHTTP2
+
+if HAVE_LIBXML2
+named_LDADD +=					\
+	$(LIBXML2_LIBS)
+endif HAVE_LIBXML2
diff --git a/bin/named/server.c b/bin/named/server.c
index 2f21fc5..6930d98 100644
--- a/bin/named/server.c
+++ b/bin/named/server.c
@@ -26,6 +26,10 @@
 #include <fstrm.h>
 #endif
 
+#ifdef HAVE_LIBSYSTEMD
+#include <systemd/sd-daemon.h>
+#endif
+
 #include <isc/aes.h>
 #include <isc/app.h>
 #include <isc/attributes.h>
@@ -219,11 +223,12 @@
 	} while (0)
 
 #define CHECKFATAL(op, msg)                         \
-	do {                                        \
+	{                                           \
 		result = (op);                      \
-		if (result != ISC_R_SUCCESS)        \
+		if (result != ISC_R_SUCCESS) {      \
 			fatal(server, msg, result); \
-	} while (0)
+		}                                   \
+	}
 
 /*%
  * Maximum ADB size for views that share a cache.  Use this limit to suppress
@@ -9929,6 +9934,15 @@ view_loaded(void *arg) {
 			      "FIPS mode is %s",
 			      FIPS_mode() ? "enabled" : "disabled");
 #endif /* ifdef HAVE_FIPS_MODE */
+
+#if HAVE_LIBSYSTEMD
+		sd_notifyf(0,
+			   "READY=1\n"
+			   "STATUS=running\n"
+			   "MAINPID=%" PRId64 "\n",
+			   (int64_t)getpid());
+#endif /* HAVE_LIBSYSTEMD */
+
 		atomic_store(&server->reload_status, NAMED_RELOAD_DONE);
 
 		isc_log_write(named_g_lctx, NAMED_LOGCATEGORY_GENERAL,
@@ -10108,6 +10122,10 @@ shutdown_server(isc_task_t *task, isc_event_t *event) {
 	UNUSED(task);
 	INSIST(task == server->task);
 
+#if HAVE_LIBSYSTEMD
+	sd_notify(0, "STOPPING=1\n");
+#endif /* HAVE_LIBSYSTEMD */
+
 	/*
 	 * We need to shutdown the interface before going
 	 * exclusive (which would pause the netmgr).
@@ -10528,6 +10546,10 @@ reload(named_server_t *server) {
 	isc_result_t result;
 
 	atomic_store(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
+#if HAVE_LIBSYSTEMD
+	sd_notify(0, "RELOADING=1\n"
+		     "STATUS=reload command received\n");
+#endif /* HAVE_LIBSYSTEMD */
 
 	CHECK(loadconfig(server));
 
@@ -10544,6 +10566,12 @@ reload(named_server_t *server) {
 		atomic_store(&server->reload_status, NAMED_RELOAD_FAILED);
 	}
 cleanup:
+#if HAVE_LIBSYSTEMD
+	sd_notifyf(0,
+		   "READY=1\n"
+		   "STATUS=reload command finished: %s\n",
+		   isc_result_totext(result));
+#endif /* HAVE_LIBSYSTEMD */
 	return (result);
 }
 
@@ -10903,6 +10931,10 @@ isc_result_t
 named_server_reconfigcommand(named_server_t *server) {
 	isc_result_t result;
 	atomic_store(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
+#if HAVE_LIBSYSTEMD
+	sd_notify(0, "RELOADING=1\n"
+		     "STATUS=reconfig command received\n");
+#endif /* HAVE_LIBSYSTEMD */
 
 	CHECK(loadconfig(server));
 
@@ -10919,6 +10951,12 @@ named_server_reconfigcommand(named_server_t *server) {
 		atomic_store(&server->reload_status, NAMED_RELOAD_FAILED);
 	}
 cleanup:
+#if HAVE_LIBSYSTEMD
+	sd_notifyf(0,
+		   "READY=1\n"
+		   "STATUS=reconfig command finished: %s\n",
+		   isc_result_totext(result));
+#endif /* HAVE_LIBSYSTEMD */
 	return (result);
 }
 
diff --git a/configure.ac b/configure.ac
index dc61f79..c3cd5d9 100644
--- a/configure.ac
+++ b/configure.ac
@@ -872,6 +872,26 @@ AS_CASE([$with_zlib],
 AC_SUBST([ZLIB_CFLAGS])
 AC_SUBST([ZLIB_LIBS])
 
+#
+# was --with-libsystemd specified?
+#
+# [pairwise: --with-libsystemd=auto, --with-libsystemd=yes, --without-libsystemd]
+AC_ARG_WITH([libsystemd],
+	    [AS_HELP_STRING([--with-libsystemd],
+			    [build with libsystemd integration [default=auto]])],
+	    [], [with_libsystemd=auto])
+
+AS_CASE([$with_libsystemd],
+	[no],[],
+	[auto],[PKG_CHECK_MODULES([LIBSYSTEMD], [libsystemd],
+				  [AC_DEFINE([HAVE_LIBSYSTEMD], [1], [Use libsystemd library])],
+				  [:])],
+	[yes],[PKG_CHECK_MODULES([LIBSYSTEMD], [libsystemd],
+				 [AC_DEFINE([HAVE_LIBSYSTEMD], [1], [Use libsystemd library])])],
+	[AC_MSG_ERROR([Specifying libsystemd installation path is not supported, adjust PKG_CONFIG_PATH instead])])
+AC_SUBST([LIBSYSTEMD_CFLAGS])
+AC_SUBST([LIBSYSTEMD_LIBS])
+
 #
 # Check if the system supports glibc-compatible backtrace() function.
 #