+#if (defined(__GNUC__) && (__GNUC__ * 100 + __GNUC_MINOR__) >= 295)
+#define ATTR_PACKED __attribute__((__packed__))
+#else
+#define ATTR_PACKED
+#endif
+
+#if !(defined(HAVE_ASPRINTF) && HAVE_ASPRINTF)
+int asprintf(char **strp, const char *fmt, ...) ATTR_PRINTF(2, 3);
+# if !(defined(HAVE_VASPRINTF) && HAVE_VASPRINTF)
+# include <stdarg.h>
+int vasprintf(char **strp, const char *fmt, va_list ap);
+# endif /* !HAVE_VASPRINTF */
+#endif /* !HAVE_ASPRINTF */
+
+static inline bool
+ATTR_PRINTF(3, 4)
+snprintf_safe(char *buf, size_t sz, const char *format, ...)
+{
+ va_list ap;
+ int rc;
+
+ va_start(ap, format);
+ rc = vsnprintf(buf, sz, format, ap);
+ va_end(ap);
+
+ return rc >= 0 && (size_t)rc < sz;
+}
+
+static inline char *
+ATTR_PRINTF(1, 0)
+vasprintf_safe(const char *fmt, va_list args)
+{
+ char *str;
+ int len;
+
+ len = vasprintf(&str, fmt, args);
+
+ if (len == -1)
+ return NULL;
+
+ return str;
+}
+
+/**
+ * A version of asprintf that returns the allocated string or NULL on error.
+ */
+static inline char *
+ATTR_PRINTF(1, 2)
+asprintf_safe(const char *fmt, ...)
+{
+ va_list args;
+ char *str;
+
+ va_start(args, fmt);
+ str = vasprintf_safe(fmt, args);
+ va_end(args);
+
+ return str;
+}
+