Tests: Add a test utils library

[lttng-tools.git] / tests / utils / utils.c

diff --git a/tests/utils/utils.c b/tests/utils/utils.c
new file mode 100644 (file)
index 0000000..e7bd9ce
--- /dev/null
+++ b/tests/utils/utils.c
@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) - 2015 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * This library is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by the
+ * Free Software Foundation; version 2.1 of the License.
+ *
+ * This library is distributed in the hope that it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
+ * for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this library; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <time.h>
+#include <assert.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <errno.h>
+
+#define NSEC_PER_SEC 1000000000ULL
+#define NSEC_PER_USEC 1000ULL
+
+static inline
+int64_t elapsed_time_ns(struct timespec *t1, struct timespec *t2)
+{
+       struct timespec delta;
+
+       assert(t1 && t2);
+       delta.tv_sec = t2->tv_sec - t1->tv_sec;
+       delta.tv_nsec = t2->tv_nsec - t1->tv_nsec;
+       return ((int64_t) NSEC_PER_SEC * (int64_t) delta.tv_sec) +
+                       (int64_t) delta.tv_nsec;
+}
+
+int usleep_safe(useconds_t usec)
+{
+       int ret = 0;
+       struct timespec t1, t2;
+       int64_t time_remaining_ns = (int64_t) usec * (int64_t) NSEC_PER_USEC;
+
+       ret = clock_gettime(CLOCK_MONOTONIC, &t1);
+       if (ret) {
+               ret = -1;
+               perror("clock_gettime");
+               goto end;
+       }
+
+       while (time_remaining_ns > 0) {
+               ret = usleep(time_remaining_ns / (int64_t) NSEC_PER_USEC);
+               if (ret && errno != EINTR) {
+                       perror("usleep");
+                       goto end;
+               }
+
+               ret = clock_gettime(CLOCK_MONOTONIC, &t2);
+               if (ret) {
+                       perror("clock_gettime");
+                       goto end;
+               }
+
+               time_remaining_ns -= elapsed_time_ns(&t1, &t2);
+       }
+end:
+       return ret;
+}