Correct round-to-ticks logic in sigtimedwait()

git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@5457 42af7a65-404d-4744-a932-0658087f49c3

2 files changed, 22 insertions, 3 deletions

diff --git a/nuttx/ChangeLog b/nuttx/ChangeLog
index 56edf9487..6c6fd7843 100644
--- a/nuttx/ChangeLog
+++ b/nuttx/ChangeLog
@@ -3812,4 +3812,7 @@
 	* include/pthread.h:  In sys/prctl.h because it is needed by
 	  pthread_[set|get]name_np()
 	* tools/kconfig.bat:  Kludge to run kconfig-frontends from a DOS shell.
+	* sched/sig_timedwait.c:  Should always move the time up to the next
+	  largest number of system ticks.  The logic was rounding.  Noted by
+	  Petteri Aimonen.
 
diff --git a/nuttx/sched/sig_timedwait.c b/nuttx/sched/sig_timedwait.c
index 1b8dfd162..d03611610 100644
--- a/nuttx/sched/sig_timedwait.c
+++ b/nuttx/sched/sig_timedwait.c
@@ -238,10 +238,25 @@ int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *info,
 
       if (timeout)
         {
-          /* Convert the timespec to milliseconds */
+          /* Convert the timespec to system clock ticks, making sure that
+           * the resultint delay is greater than or equal to the requested
+           * time in nanoseconds.
+           */
 
-          waitticks = MSEC2TICK(timeout->tv_sec  * MSEC_PER_SEC
-                                + timeout->tv_nsec / NSEC_PER_MSEC);
+#ifdef CONFIG_HAVE_LONG_LONG
+          uint64_t waitticks64 = (timeout->tv_sec * NSEC_PER_SEC +
+                                  timeout->tv_nsec + NSEC_PER_TICK - 1) /
+                                  NSEC_PER_TICK;
+          DEBUGASSERT(waitticks64 <= UINT32_MAX);
+          waitticks = (uint32_t)waitticks64;
+#else
+          uint32_t waitmsec;
+
+          DEBUGASSERT(timeout->tv_sec < UINT32_MAX / MSEC_PER_SEC);
+          waitmsec = timeout->tv_sec * MSEC_PER_SEC +
+                    (timeout->tv_nsec + NSEC_PER_MSEC - 1) / NSEC_PER_MSEC;
+          waitticks = (waitmsec + MSEC_PER_TICK - 1) / MSEC_PER_TICK;
+#endif
 
           /* Create a watchdog */
 
@@ -326,6 +341,7 @@ int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *info,
         {
           memcpy(info, &rtcb->sigunbinfo, sizeof(struct siginfo));
         }
+
       irqrestore(saved_state);
    }