varlink: introduce varlink_call_and_log() which calls and then logs an error

As it turns out we do this in a similar way at various times (and
sometimes incorrectly), hence add a common implementation to share the
code and fix the incorrect behaviour.

src/shared/varlink.c

@@ -2259,6 +2259,7 @@ int varlink_callb_ap(
         int r;
 
         assert_return(v, -EINVAL);
+        assert_return(method, -EINVAL);
 
         r = json_buildv(&parameters, ap);
         if (r < 0)
@@ -2267,6 +2268,54 @@ int varlink_callb_ap(
         return varlink_call_full(v, method, parameters, ret_parameters, ret_error_id, ret_flags);
 }
 
+int varlink_call_and_log(
+                Varlink *v,
+                const char *method,
+                JsonVariant *parameters,
+                JsonVariant **ret_parameters) {
+
+        JsonVariant *reply = NULL;
+        const char *error_id = NULL;
+        int r;
+
+        assert_return(v, -EINVAL);
+        assert_return(method, -EINVAL);
+
+        r = varlink_call(v, method, parameters, &reply, &error_id);
+        if (r < 0)
+                return log_error_errno(r, "Failed to issue %s() varlink call: %m", method);
+        if (error_id)
+                return log_error_errno(varlink_error_to_errno(error_id, reply),
+                                         "Failed to issue %s() varlink call: %s", method, error_id);
+
+        if (ret_parameters)
+                *ret_parameters = TAKE_PTR(reply);
+
+        return 0;
+}
+
+int varlink_callb_and_log(
+                Varlink *v,
+                const char *method,
+                JsonVariant **ret_parameters,
+                ...) {
+
+        _cleanup_(json_variant_unrefp) JsonVariant *parameters = NULL;
+        va_list ap;
+        int r;
+
+        assert_return(v, -EINVAL);
+        assert_return(method, -EINVAL);
+
+        va_start(ap, ret_parameters);
+        r = json_buildv(&parameters, ap);
+        va_end(ap);
+        if (r < 0)
+                return log_error_errno(r, "Failed to build JSON message: %m");
+
+        return varlink_call_and_log(v, method, parameters, ret_parameters);
+}
+
 static void varlink_collect_context_free(VarlinkCollectContext *cc) {
         assert(cc);
 

src/shared/varlink.h

@@ -92,6 +92,8 @@ int varlink_call_full(Varlink *v, const char *method, JsonVariant *parameters, J
 static inline int varlink_call(Varlink *v, const char *method, JsonVariant *parameters, JsonVariant **ret_parameters, const char **ret_error_id) {
         return varlink_call_full(v, method, parameters, ret_parameters, ret_error_id, NULL);
 }
+int varlink_call_and_log(Varlink *v, const char *method, JsonVariant *parameters, JsonVariant **ret_parameters);
+
 int varlink_callb_ap(Varlink *v, const char *method, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags, va_list ap);
 static inline int varlink_callb_full(Varlink *v, const char *method, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags, ...) {
         va_list ap;
@@ -111,6 +113,7 @@ static inline int varlink_callb(Varlink *v, const char *method, JsonVariant **re
         va_end(ap);
         return r;
 }
+int varlink_callb_and_log(Varlink *v, const char *method, JsonVariant **ret_parameters, ...);
 
 /* Send method call and begin collecting all 'more' replies into an array, finishing when a final reply is sent */
 int varlink_collect(Varlink *v, const char *method, JsonVariant *parameters, JsonVariant **ret_parameters, const char **ret_error_id, VarlinkReplyFlags *ret_flags);