dns: return error reason from nm_dns_plugin_update()

For logging, if the plugin fails with update, it should return a reason
that we can log.

Note that both dnsmasq and system-resolved plugins do the update asynchronously
(of course). Hence, usually they never fail right away, and there isn't really
possibility to handle the failure later. Still, we should print something sensible
for that we need information what went wrong.

6 files changed, 33 insertions, 12 deletions

diff --git a/src/dns/nm-dns-dnsmasq.c b/src/dns/nm-dns-dnsmasq.c
index c57522bf87..ce89b07865 100644
--- a/src/dns/nm-dns-dnsmasq.c
+++ b/src/dns/nm-dns-dnsmasq.c
@@ -365,7 +365,8 @@ static gboolean
 update (NMDnsPlugin *plugin,
         const NMGlobalDnsConfig *global_config,
         const CList *ip_config_lst_head,
-        const char *hostname)
+        const char *hostname,
+        GError **error)
 {
 	NMDnsDnsmasq *self = NM_DNS_DNSMASQ (plugin);
 	NMDnsDnsmasqPrivate *priv = NM_DNS_DNSMASQ_GET_PRIVATE (self);
diff --git a/src/dns/nm-dns-manager.c b/src/dns/nm-dns-manager.c
index 1d009c98f5..d798c66097 100644
--- a/src/dns/nm-dns-manager.c
+++ b/src/dns/nm-dns-manager.c
@@ -1428,13 +1428,15 @@ update_dns (NMDnsManager *self,
 		nm_dns_plugin_update (priv->sd_resolve_plugin,
 		                      global_config,
 		                      _ip_config_lst_head (self),
-		                      priv->hostname);
+		                      priv->hostname,
+		                      NULL);
 	}
 
 	/* Let any plugins do their thing first */
 	if (priv->plugin) {
 		NMDnsPlugin *plugin = priv->plugin;
 		const char *plugin_name = nm_dns_plugin_get_name (plugin);
+		gs_free_error GError *plugin_error = NULL;
 
 		if (nm_dns_plugin_is_caching (plugin)) {
 			if (no_caching) {
@@ -1449,8 +1451,9 @@ update_dns (NMDnsManager *self,
 		if (!nm_dns_plugin_update (plugin,
 		                           global_config,
 		                           _ip_config_lst_head (self),
-		                           priv->hostname)) {
-			_LOGW ("update-dns: plugin %s update failed", plugin_name);
+		                           priv->hostname,
+		                           &plugin_error)) {
+			_LOGW ("update-dns: plugin %s update failed: %s", plugin_name, plugin_error->message);
 
 			/* If the plugin failed to update, we shouldn't write out a local
 			 * caching DNS configuration to resolv.conf.
diff --git a/src/dns/nm-dns-plugin.c b/src/dns/nm-dns-plugin.c
index 62488a454e..9ca7392f56 100644
--- a/src/dns/nm-dns-plugin.c
+++ b/src/dns/nm-dns-plugin.c
@@ -64,14 +64,16 @@ gboolean
 nm_dns_plugin_update (NMDnsPlugin *self,
                       const NMGlobalDnsConfig *global_config,
                       const CList *ip_config_lst_head,
-                      const char *hostname)
+                      const char *hostname,
+                      GError **error)
 {
 	g_return_val_if_fail (NM_DNS_PLUGIN_GET_CLASS (self)->update != NULL, FALSE);
 
 	return NM_DNS_PLUGIN_GET_CLASS (self)->update (self,
 	                                               global_config,
 	                                               ip_config_lst_head,
-	                                               hostname);
+	                                               hostname,
+	                                               error);
 }
 
 gboolean
diff --git a/src/dns/nm-dns-plugin.h b/src/dns/nm-dns-plugin.h
index 286a4fb196..1a12c8d928 100644
--- a/src/dns/nm-dns-plugin.h
+++ b/src/dns/nm-dns-plugin.h
@@ -36,7 +36,8 @@ typedef struct {
 	gboolean (*update) (NMDnsPlugin *self,
 	                    const NMGlobalDnsConfig *global_config,
 	                    const CList *ip_config_lst_head,
-	                    const char *hostname);
+	                    const char *hostname,
+	                    GError **error);
 
 	const char *plugin_name;
 
@@ -64,7 +65,8 @@ const char *nm_dns_plugin_get_name (NMDnsPlugin *self);
 gboolean nm_dns_plugin_update (NMDnsPlugin *self,
                                const NMGlobalDnsConfig *global_config,
                                const CList *ip_config_lst_head,
-                               const char *hostname);
+                               const char *hostname,
+                               GError **error);
 
 void nm_dns_plugin_stop (NMDnsPlugin *self);
 
diff --git a/src/dns/nm-dns-systemd-resolved.c b/src/dns/nm-dns-systemd-resolved.c
index c9fb773f52..04b8012997 100644
--- a/src/dns/nm-dns-systemd-resolved.c
+++ b/src/dns/nm-dns-systemd-resolved.c
@@ -338,7 +338,8 @@ static gboolean
 update (NMDnsPlugin *plugin,
         const NMGlobalDnsConfig *global_config,
         const CList *ip_config_lst_head,
-        const char *hostname)
+        const char *hostname,
+        GError **error)
 {
 	NMDnsSystemdResolved *self = NM_DNS_SYSTEMD_RESOLVED (plugin);
 	gs_unref_hashtable GHashTable *interfaces = NULL;
diff --git a/src/dns/nm-dns-unbound.c b/src/dns/nm-dns-unbound.c
index e9515ba351..3884ce9a51 100644
--- a/src/dns/nm-dns-unbound.c
+++ b/src/dns/nm-dns-unbound.c
@@ -27,9 +27,11 @@ static gboolean
 update (NMDnsPlugin *plugin,
         const NMGlobalDnsConfig *global_config,
         const CList *ip_config_lst_head,
-        const char *hostname)
+        const char *hostname,
+        GError **error)
 {
 	char *argv[] = { DNSSEC_TRIGGER_PATH, "--async", "--update", NULL };
+	gs_free_error GError *local = NULL;
 	int status;
 
 	/* TODO: We currently call a script installed with the dnssec-trigger
@@ -41,9 +43,19 @@ update (NMDnsPlugin *plugin,
 	 * without calling custom scripts. The dnssec-trigger functionality
 	 * may be eventually merged into NetworkManager.
 	 */
-	if (!g_spawn_sync ("/", argv, NULL, 0, NULL, NULL, NULL, NULL, &status, NULL))
+	if (!g_spawn_sync ("/", argv, NULL, 0, NULL, NULL, NULL, NULL, &status, &local)) {
+		nm_utils_error_set (error, NM_UTILS_ERROR_UNKNOWN,
+		                    "error spawning dns-trigger: %s",
+		                    local->message);
 		return FALSE;
-	return (status == 0);
+	}
+	if (status != 0) {
+		nm_utils_error_set (error, NM_UTILS_ERROR_UNKNOWN,
+		                    "dns-trigger exited with error code %d",
+		                    status);
+		return FALSE;
+	}
+	return TRUE;
 }
 
 /*****************************************************************************/