diff --git a/src/ext/eventdns.c b/src/ext/eventdns.c
index a0c7ff29fa..1894cbea53 100644
--- a/src/ext/eventdns.c
+++ b/src/ext/eventdns.c
@@ -388,7 +388,7 @@ debug_ntoa(u32 address)
 {
 	static char buf[32];
 	u32 a = ntohl(address);
-	snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
+	tor_snprintf(buf, sizeof(buf), "%d.%d.%d.%d",
 			(int)(u8)((a>>24)&0xff),
 			(int)(u8)((a>>16)&0xff),
 			(int)(u8)((a>>8 )&0xff),
@@ -436,12 +436,7 @@ evdns_log(int warn, const char *fmt, ...)
 	if (!evdns_log_fn)
 		return;
 	va_start(args,fmt);
-#ifdef _WIN32
-	_vsnprintf(buf, sizeof(buf), fmt, args);
-#else
-	vsnprintf(buf, sizeof(buf), fmt, args);
-#endif
-	buf[sizeof(buf)-1] = '\0';
+	tor_vsnprintf(buf, sizeof(buf), fmt, args);
 	evdns_log_fn(warn, buf);
 	va_end(args);
 }
@@ -762,7 +757,7 @@ reply_handle(struct evdns_request *const req, u16 flags, u32 ttl, struct reply *
 			/* we regard these errors as marking a bad nameserver */
 			if (req->reissue_count < global_max_reissues) {
 				char msg[64];
-				snprintf(msg, sizeof(msg), "Bad response %d (%s)",
+				tor_snprintf(msg, sizeof(msg), "Bad response %d (%s)",
 						 error, evdns_err_to_string(error));
 				nameserver_failed(req->ns, msg);
 				if (!request_reissue(req)) return;
@@ -1705,7 +1700,7 @@ evdns_server_request_add_ptr_reply(struct evdns_server_request *req, struct in_a
 	assert(!(in && inaddr_name));
 	if (in) {
 		a = ntohl(in->s_addr);
-		snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
+		tor_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
 				(int)(u8)((a	)&0xff),
 				(int)(u8)((a>>8 )&0xff),
 				(int)(u8)((a>>16)&0xff),
@@ -2638,7 +2633,7 @@ int evdns_resolve_reverse(const struct in_addr *in, int flags, evdns_callback_ty
 	u32 a;
 	assert(in);
 	a = ntohl(in->s_addr);
-	snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
+	tor_snprintf(buf, sizeof(buf), "%d.%d.%d.%d.in-addr.arpa",
 			(int)(u8)((a	)&0xff),
 			(int)(u8)((a>>8 )&0xff),
 			(int)(u8)((a>>16)&0xff),