From 32f556637de8c0b9de626290f0859fc24f7ccf89 Mon Sep 17 00:00:00 2001
From: Andrew Johnson <anj@aps.anl.gov>
Date: Mon, 18 Jun 2012 14:52:03 -0500
Subject: [PATCH] libCom/osi: Fixed all epicsThreadSleep() implementations

All are now robust against overflow, NAN or negative argument.
Passing seconds=0 calls the OS scheduler, offering to yield.
Passing seconds>0 delays at least the requested time, up to a
limit which usually depends on the OS tick rate.
---
 src/libCom/osi/os/RTEMS/osdThread.c   | 18 +++++++++---------
 src/libCom/osi/os/WIN32/osdThread.c   | 17 +++++++----------
 src/libCom/osi/os/posix/osdThread.c   | 12 +++++++++---
 src/libCom/osi/os/vxWorks/osdThread.c | 11 +++++++----
 4 files changed, 32 insertions(+), 26 deletions(-)

diff --git a/src/libCom/osi/os/RTEMS/osdThread.c b/src/libCom/osi/os/RTEMS/osdThread.c
index 7fa541bfd..f735671b1 100644
--- a/src/libCom/osi/os/RTEMS/osdThread.c
+++ b/src/libCom/osi/os/RTEMS/osdThread.c
@@ -25,6 +25,7 @@
 #include <stdio.h>
 #include <assert.h>
 #include <syslog.h>
+#include <limits.h>
 
 #include <rtems.h>
 #include <rtems/error.h>
@@ -364,16 +365,15 @@ epicsThreadSleep (double seconds)
 {
     rtems_status_code sc;
     rtems_interval delay;
-    extern double rtemsTicksPerTwoSeconds_double;
-    
-    if (seconds <= 0.0) {
-        delay = 0;
+    extern double rtemsTicksPerSecond_double;
+
+    if (seconds > 0.0) {
+        seconds *= rtemsTicksPerSecond_double;
+        seconds += 0.99999999;  /* 8 9s here is optimal */
+        delay = (seconds >= INT_MAX) ? INT_MAX : (int) seconds;
     }
-    else {
-        delay = seconds * rtemsTicksPerTwoSeconds_double;
-        delay = (delay + 1) / 2;
-        if (delay == 0)
-            delay++;
+    else {  /* seconds <= 0 or NAN */
+        delay = 0;
     }
     sc = rtems_task_wake_after (delay);
     if(sc != RTEMS_SUCCESSFUL)
diff --git a/src/libCom/osi/os/WIN32/osdThread.c b/src/libCom/osi/os/WIN32/osdThread.c
index 86f7b7df7..46c1009c8 100644
--- a/src/libCom/osi/os/WIN32/osdThread.c
+++ b/src/libCom/osi/os/WIN32/osdThread.c
@@ -779,18 +779,15 @@ epicsShareFunc void epicsShareAPI epicsThreadSleep ( double seconds )
     static const unsigned mSecPerSec = 1000;
     DWORD milliSecDelay;
 
-    if ( seconds <= 0.0 ) {
+    if ( seconds > 0.0 ) {
+        seconds *= mSecPerSec;
+        seconds += 0.99999999;  /* 8 9s here is optimal */
+        milliSecDelay = ( seconds >= INFINITE ) ?
+            INFINITE - 1 : ( DWORD ) seconds;
+    }
+    else {  /* seconds <= 0 or NAN */
         milliSecDelay = 0u;
     }
-    else if ( seconds >= INFINITE / mSecPerSec ) {
-        milliSecDelay = INFINITE - 1;
-    }
-    else {
-        milliSecDelay = ( DWORD ) ( ( seconds * mSecPerSec ) + 0.5 );
-        if ( milliSecDelay == 0 ) {
-            milliSecDelay = 1;
-        }
-    }
     Sleep ( milliSecDelay );
 }
 
diff --git a/src/libCom/osi/os/posix/osdThread.c b/src/libCom/osi/os/posix/osdThread.c
index 3755d943a..30583e162 100644
--- a/src/libCom/osi/os/posix/osdThread.c
+++ b/src/libCom/osi/os/posix/osdThread.c
@@ -673,9 +673,15 @@ epicsShareFunc void epicsShareAPI epicsThreadSleep(double seconds)
     struct timespec remainingTime;
     double nanoseconds;
 
-    delayTime.tv_sec = (time_t)seconds;
-    nanoseconds = (seconds - (double)delayTime.tv_sec) *1e9;
-    delayTime.tv_nsec = (long)nanoseconds;
+    if (seconds > 0) {
+        delayTime.tv_sec = seconds;
+        nanoseconds = (seconds - delayTime.tv_sec) *1e9;
+        delayTime.tv_nsec = nanoseconds;
+    }
+    else {
+        delayTime.tv_sec = 0;
+        delayTime.tv_nsec = 0;
+    }
     while (nanosleep(&delayTime, &remainingTime) == -1 &&
            errno == EINTR)
         delayTime = remainingTime;
diff --git a/src/libCom/osi/os/vxWorks/osdThread.c b/src/libCom/osi/os/vxWorks/osdThread.c
index 09d451fab..69034b794 100644
--- a/src/libCom/osi/os/vxWorks/osdThread.c
+++ b/src/libCom/osi/os/vxWorks/osdThread.c
@@ -18,6 +18,7 @@
 #include <stdlib.h>
 #include <stddef.h>
 #include <stdio.h>
+#include <limits.h>
 
 #include <vxWorks.h>
 #include <taskLib.h>
@@ -279,11 +280,13 @@ void epicsThreadSleep(double seconds)
     STATUS status;
     int ticks;
 
-    if(seconds<=0.0) {
+    if (seconds > 0.0) {
+        seconds *= sysClkRateGet();
+        seconds += 0.99999999;  /* 8 9s here is optimal */
+        ticks = (seconds >= INT_MAX) ? INT_MAX : (int) seconds;
+    }
+    else {  /* seconds <= 0 or NAN */
         ticks = 0;
-    } else {
-        ticks = seconds*sysClkRateGet() + 0.5;
-        if(ticks<=0) ticks = 1;
     }
     status = taskDelay(ticks);
     if(status) errlogPrintf("epicsThreadSleep\n");