rem: pkg: Implement the systemd notification protocol manually to remove dependency on libsystemd.

Merge branch 'aydin/standalone-notification' into 'main'

See merge request isc-projects/bind9!10263

bin/named/Makefile.am

@@ -13,7 +13,6 @@ AM_CPPFLAGS +=				\
 	$(MAXMINDDB_CFLAGS)		\
 	$(DNSTAP_CFLAGS)		\
 	$(LIBUV_CFLAGS)			\
-	$(LIBSYSTEMD_CFLAGS)		\
 	$(ZLIB_CFLAGS)
 
 if HAVE_JSON_C
@@ -108,7 +107,6 @@ named_LDADD =					\
 	$(MAXMINDDB_LIBS)			\
 	$(DNSTAP_LIBS)				\
 	$(LIBUV_LIBS)				\
-	$(LIBSYSTEMD_LIBS)			\
 	$(ZLIB_LIBS)
 
 if HAVE_JSON_C

bin/named/include/named/os.h

@@ -18,6 +18,7 @@
 #include <pwd.h>
 #include <stdbool.h>
 
+#include <isc/formatcheck.h>
 #include <isc/types.h>
 
 void
@@ -73,3 +74,15 @@ named_os_started(void);
 
 const char *
 named_os_uname(void);
+
+#ifdef __linux__
+void
+named_os_notify_systemd(const char *restrict format, ...)
+	ISC_FORMAT_PRINTF(1, 2);
+
+void
+named_os_notify_close(void);
+#else /* __linux__ */
+#define named_os_notify_systemd(...)
+#define named_os_notify_close(...)
+#endif /* __linux__ */

bin/named/os.c

@@ -36,6 +36,7 @@
 #include <unistd.h>
 
 #include <isc/buffer.h>
+#include <isc/errno.h>
 #include <isc/file.h>
 #include <isc/result.h>
 #include <isc/strerr.h>
@@ -60,6 +61,7 @@ static int devnullfd = -1;
 static struct passwd *runas_pw = NULL;
 static bool done_setuid = false;
 static int dfd[2] = { -1, -1 };
+static int notify_fd = -1;
 
 static uid_t saved_uid = (uid_t)-1;
 static gid_t saved_gid = (gid_t)-1;
@@ -273,6 +275,79 @@ setperms(uid_t uid, gid_t gid) {
 	}
 }
 
+#ifdef __linux__
+static isc_result_t
+connect_systemd_notify_unix(char *path) {
+	struct sockaddr_un addr;
+	isc_result_t result = ISC_R_SUCCESS;
+	size_t len;
+
+	addr.sun_family = AF_UNIX;
+
+	len = strlcpy(addr.sun_path, path, sizeof(addr.sun_path));
+	if (len >= sizeof(addr.sun_path)) {
+		return ISC_R_NOSPACE;
+	}
+
+	/* Convert abstract unix sockets */
+	if (addr.sun_path[0] == '@') {
+		addr.sun_path[0] = '\0';
+	}
+
+	notify_fd = socket(AF_UNIX, SOCK_DGRAM | SOCK_CLOEXEC, 0);
+	if (notify_fd < 0) {
+		return isc_errno_toresult(errno);
+	}
+
+	if (connect(notify_fd, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+		result = isc_errno_toresult(errno);
+		close(notify_fd);
+		notify_fd = -1;
+	}
+
+	return result;
+}
+
+static void
+setup_systemd_notify(void) {
+	isc_result_t result;
+	char *path;
+
+	REQUIRE(notify_fd == -1);
+
+	path = getenv("NOTIFY_SOCKET");
+
+	/* systemd notification is not set, oh well. */
+	if (path == NULL) {
+		return;
+	}
+
+	if (path[0] == '/' || path[0] == '@') {
+		result = connect_systemd_notify_unix(path);
+	} else if (strncmp(path, "vsock", 5) == 0) {
+		result = ISC_R_FAMILYNOSUPPORT;
+	} else {
+		result = ISC_R_INVALIDPROTO;
+	}
+
+	if (result != ISC_R_SUCCESS) {
+		RUNTIME_CHECK(notify_fd == -1);
+		isc_log_write(
+			NAMED_LOGCATEGORY_GENERAL, NAMED_LOGMODULE_MAIN,
+			ISC_LOG_WARNING,
+			"failed to connect to notification socket '%s': %s",
+			path, isc_result_totext(result));
+	} else {
+		RUNTIME_CHECK(notify_fd != -1);
+		isc_log_write(NAMED_LOGCATEGORY_GENERAL, NAMED_LOGMODULE_MAIN,
+			      ISC_LOG_INFO,
+			      "connected to notification socket '%s'", path);
+	}
+}
+#else /* __linux__ */
+#define setup_systemd_notify(...)
+#endif /* __linux__ */
+
 static void
 setup_syslog(const char *progname) {
 	int options;
@@ -287,6 +362,7 @@ setup_syslog(const char *progname) {
 void
 named_os_init(const char *progname) {
 	setup_syslog(progname);
+	setup_systemd_notify();
 #if HAVE_LIBCAP
 	linux_initialprivs();
 #endif /* HAVE_LIBCAP */
@@ -362,6 +438,13 @@ named_os_daemonize(void) {
 			(void)dup2(devnullfd, STDERR_FILENO);
 		}
 	}
+
+	/*
+	 * Will be closed from SOCK_CLOEXEC but should be set to -1 again before
+	 * reconnecting to the notification socket.
+	 */
+	notify_fd = -1;
+	setup_systemd_notify();
 }
 
 void
@@ -865,3 +948,38 @@ named_os_uname(void) {
 	}
 	return unamep;
 }
+
+#ifdef __linux__
+void
+named_os_notify_systemd(const char *restrict format, ...) {
+	char buffer[512];
+	va_list ap;
+	int len;
+
+	if (notify_fd == -1 || format == NULL) {
+		return;
+	}
+
+	va_start(ap, format);
+	len = vsnprintf(buffer, sizeof(buffer), format, ap);
+	va_end(ap);
+
+	/* Be very loud if notification is too long */
+	RUNTIME_CHECK(len > 0 && len < (int)sizeof(buffer));
+
+	if (write(notify_fd, buffer, len) != len) {
+		isc_log_write(NAMED_LOGCATEGORY_GENERAL, NAMED_LOGMODULE_MAIN,
+			      ISC_LOG_ERROR,
+			      "failed writing to notification socket '%s'",
+			      isc_result_totext(isc_errno_toresult(errno)));
+	}
+}
+
+void
+named_os_notify_close(void) {
+	if (notify_fd != -1) {
+		close(notify_fd);
+		notify_fd = -1;
+	}
+}
+#endif /* __linux__ */

bin/named/server.c

@@ -28,10 +28,6 @@
 #include <fstrm.h>
 #endif
 
-#ifdef HAVE_LIBSYSTEMD
-#include <systemd/sd-daemon.h>
-#endif
-
 #include <isc/async.h>
 #include <isc/attributes.h>
 #include <isc/base64.h>
@@ -9402,13 +9398,10 @@ view_loaded(void *arg) {
 			      ISC_LOG_NOTICE, "FIPS mode is %s",
 			      isc_crypto_fips_mode() ? "enabled" : "disabled");
 
-#if HAVE_LIBSYSTEMD
-		sd_notifyf(0,
-			   "READY=1\n"
-			   "STATUS=running\n"
-			   "MAINPID=%" PRId64 "\n",
-			   (int64_t)getpid());
-#endif /* HAVE_LIBSYSTEMD */
+		named_os_notify_systemd("READY=1\n"
+					"STATUS=running\n"
+					"MAINPID=%" PRId64 "\n",
+					(int64_t)getpid());
 
 		atomic_store(&server->reload_status, NAMED_RELOAD_DONE);
 
@@ -9547,9 +9540,8 @@ shutdown_server(void *arg) {
 	bool flush = server->flushonshutdown;
 	named_cache_t *nsc = NULL;
 
-#if HAVE_LIBSYSTEMD
-	sd_notify(0, "STOPPING=1\n");
-#endif /* HAVE_LIBSYSTEMD */
+	named_os_notify_systemd("STOPPING=1\n");
+	named_os_notify_close();
 
 	isc_signal_stop(server->sighup);
 	isc_signal_destroy(&server->sighup);
@@ -10041,17 +10033,11 @@ reload(named_server_t *server) {
 	isc_result_t result;
 
 	atomic_store(&server->reload_status, NAMED_RELOAD_IN_PROGRESS);
-#if HAVE_LIBSYSTEMD
-	char buf[512];
-	int n = snprintf(buf, sizeof(buf),
-			 "RELOADING=1\n"
-			 "MONOTONIC_USEC=%" PRIu64 "\n"
-			 "STATUS=reload command received\n",
-			 (uint64_t)isc_time_monotonic() / NS_PER_US);
-	if (n > 0 && (size_t)n < sizeof(buf)) {
-		sd_notify(0, buf);
-	}
-#endif /* HAVE_LIBSYSTEMD */
+
+	named_os_notify_systemd("RELOADING=1\n"
+				"MONOTONIC_USEC=%" PRIu64 "\n"
+				"STATUS=reload command received\n",
+				(uint64_t)isc_time_monotonic() / NS_PER_US);
 
 	CHECK(loadconfig(server));
 
@@ -10066,12 +10052,10 @@ 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 */
+	named_os_notify_systemd("READY=1\n"
+				"STATUS=reload command finished: %s\n",
+				isc_result_totext(result));
+
 	return result;
 }
 
@@ -10542,17 +10526,11 @@ 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
-	char buf[512];
-	int n = snprintf(buf, sizeof(buf),
-			 "RELOADING=1\n"
-			 "MONOTONIC_USEC=%" PRIu64 "\n"
-			 "STATUS=reconfig command received\n",
-			 (uint64_t)isc_time_monotonic() / NS_PER_US);
-	if (n > 0 && (size_t)n < sizeof(buf)) {
-		sd_notify(0, buf);
-	}
-#endif /* HAVE_LIBSYSTEMD */
+
+	named_os_notify_systemd("RELOADING=1\n"
+				"MONOTONIC_USEC=%" PRIu64 "\n"
+				"STATUS=reconfig command received\n",
+				(uint64_t)isc_time_monotonic() / NS_PER_US);
 
 	CHECK(loadconfig(server));
 
@@ -10567,12 +10545,10 @@ 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 */
+	named_os_notify_systemd("READY=1\n"
+				"STATUS=reconfig command finished: %s\n",
+				isc_result_totext(result));
+
 	return result;
 }
 

configure.ac

@@ -859,26 +859,6 @@ 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.
 #