Fix glibc version detection.
Simplify Posix timer detection.
/* Macro to convert two thirty two bit values into a sixty four bit one */
#define TWO32TO64(a, b) ((((uint64_t)(a)) << 32) + (b))
+/*
+ * Check for the existence and support of POSIX timers. The standard
+ * says that the _POSIX_TIMERS macro will have a positive value if they
+ * are available.
+ *
+ * However, we want an additional constraint: that the timer support does
+ * not require an extra library dependency. Early versions of glibc
+ * require -lrt to be specified on the link line to access the timers,
+ * so this needs to be checked for.
+ *
+ * It is worse because some libraries define __GLIBC__ but don't
+ * support the version testing macro (e.g. uClibc). This means
+ * an extra check is needed.
+ *
+ * The final condition is:
+ * "have posix timers and either not glibc or glibc without -lrt"
+ *
+ * The nested #if sequences are required to avoid using a parameterised
+ * macro that might be undefined.
+ */
+#undef OSSL_POSIX_TIMER_OKAY
+#if defined(_POSIX_TIMERS) && _POSIX_TIMERS > 0
+# if defined(__GLIBC__)
+# if defined(__GLIBC_PREREQ)
+# if __GLIBC_PREREQ(2, 17)
+# define OSSL_POSIX_TIMER_OKAY
+# endif
+# endif
+# else
+# define OSSL_POSIX_TIMER_OKAY
+# endif
+#endif
+
#ifndef OPENSSL_NO_ENGINE
/* non-NULL if default_RAND_meth is ENGINE-provided */
static ENGINE *funct_ref;
@@ -228,11 +261,7 @@ static uint64_t get_timer_bits(void)
}
#else
-# if defined(_POSIX_C_SOURCE) \
- && defined(_POSIX_TIMERS) \
- && _POSIX_C_SOURCE >= 199309L \
- && (!defined(__GLIBC__) \
- || (defined(__GLIBC_PREREQ) && __GLIBC_PREREQ(2, 17)))
+#if defined(OSSL_POSIX_TIMER_OKAY)
{
struct timespec ts;
clockid_t cid;
