diff --git a/server/include/utils.h b/server/include/utils.h
index 4e822af04..1f9eebdcd 100644
--- a/server/include/utils.h
+++ b/server/include/utils.h
@@ -68,6 +68,15 @@ void epoch_reset();
  */
 void print(enum log_level lvl, const char *fmt, ...);
 
+/** Safely append a format string to an existing string.
+ *
+ * This function is similar to strlcat() from BSD.
+ */
+int strap(char *dest, size_t size, const char *fmt,  ...);
+
+/** Variable arguments (stdarg) version of strap() */
+int vstrap(char *dest, size_t size, const char *fmt, va_list va);
+
 /** Convert integer to cpu_set_t.
  *
  * @param set A cpu bitmask
diff --git a/server/src/utils.c b/server/src/utils.c
index c332e7799..1cd554765 100644
--- a/server/src/utils.c
+++ b/server/src/utils.c
@@ -35,6 +35,25 @@ void epoch_reset()
 	clock_gettime(CLOCK_REALTIME, &epoch);
 }
 
+int strap(char *dest, size_t size, const char *fmt,  ...)
+{
+	int ret;
+	
+	va_list ap;
+	va_start(ap, fmt);
+	ret = vstrap(dest, size, fmt, ap);
+	va_end(ap);
+	
+	return ret;
+}
+
+int vstrap(char *dest, size_t size, const char *fmt, va_list ap)
+{
+	int len = strlen(dest);
+
+	return vsnprintf(dest + len, size - len, fmt, ap);
+}
+
 void print(enum log_level lvl, const char *fmt, ...)
 {
 	struct timespec ts;