1 files changed, 62 insertions, 0 deletions
diff --git a/ext/kgio/broken_system_compat.h b/ext/kgio/broken_system_compat.h
new file mode 100644
index 0000000..e67a56c
--- /dev/null
+++ b/ext/kgio/broken_system_compat.h
@@ -0,0 +1,62 @@
+/*
+ * this header includes functions to support broken systems
+ * without clock_gettime() or CLOCK_MONOTONIC
+ */
+
+#ifndef HAVE_TYPE_CLOCKID_T
+typedef int clockid_t;
+#endif
+
+#ifndef HAVE_CLOCK_GETTIME
+#  ifndef CLOCK_REALTIME
+#    define CLOCK_REALTIME 0 /* whatever */
+#  endif
+static int fake_clock_gettime(clockid_t clk_id, struct timespec *res)
+{
+        struct timeval tv;
+        int r = gettimeofday(&tv, NULL);
+
+        assert(0 == r && "gettimeofday() broke!?");
+        res->tv_sec = tv.tv_sec;
+        res->tv_nsec = tv.tv_usec * 1000;
+
+        return r;
+}
+#  define clock_gettime fake_clock_gettime
+#endif /* broken systems w/o clock_gettime() */
+
+/*
+ * UGH
+ * CLOCK_MONOTONIC is not guaranteed to be a macro, either
+ */
+#ifndef CLOCK_MONOTONIC
+#  if (!defined(_POSIX_MONOTONIC_CLOCK) || !defined(HAVE_CLOCK_MONOTONIC))
+#    define CLOCK_MONOTONIC CLOCK_REALTIME
+#  endif
+#endif
+
+/*
+ * Availability of a monotonic clock needs to be detected at runtime
+ * since we could've been built on a different system than we're run
+ * under.
+ */
+static clockid_t hopefully_CLOCK_MONOTONIC;
+
+static int check_clock(void)
+{
+        struct timespec now;
+
+        hopefully_CLOCK_MONOTONIC = CLOCK_MONOTONIC;
+
+        /* we can't check this reliably at compile time */
+        if (clock_gettime(CLOCK_MONOTONIC, &now) == 0)
+                return 1;
+
+        if (clock_gettime(CLOCK_REALTIME, &now) == 0) {
+                hopefully_CLOCK_MONOTONIC = CLOCK_REALTIME;
+                rb_warn("CLOCK_MONOTONIC not available, "
+                        "falling back to CLOCK_REALTIME");
+                return 2;
+        }
+        return -1;
+}