Correctly normalize timevals before calling select()

When normalizing timevals, we need to bound the tv_usec member to
0-999999 inclusive, otherwise select() may return EINVAL.

When rounding timevals to the nearest millisecond in the UNIX event
dispatcher, pass the timeval through normalizeTimeval() when returning.

As discovered on Mac OS X with tst_QFutureWatcher, starting a 10 second
timer would end up calling select() with timeval = { 9l, 1000000 },
resulting in numerous "select: Invalid argument" warnings being printed
to the console.

Change-Id: Ic539e935bf847e0d4c22a73ad203e3a7a81d0690
Reviewed-by: Olivier Goffart <ogoffart@woboq.com>

2 files changed, 5 insertions, 9 deletions

diff --git a/src/corelib/kernel/qcore_unix_p.h b/src/corelib/kernel/qcore_unix_p.h
index 00ec4af203..e7259d29c9 100644
--- a/src/corelib/kernel/qcore_unix_p.h
+++ b/src/corelib/kernel/qcore_unix_p.h
@@ -101,13 +101,13 @@ QT_BEGIN_NAMESPACE
 // Internal operator functions for timevals
 inline timeval &normalizedTimeval(timeval &t)
 {
-    while (t.tv_usec > 1000000l) {
+    while (t.tv_usec >= 1000000) {
         ++t.tv_sec;
-        t.tv_usec -= 1000000l;
+        t.tv_usec -= 1000000;
     }
-    while (t.tv_usec < 0l) {
+    while (t.tv_usec < 0) {
         --t.tv_sec;
-        t.tv_usec += 1000000l;
+        t.tv_usec += 1000000;
     }
     return t;
 }
diff --git a/src/corelib/kernel/qeventdispatcher_unix.cpp b/src/corelib/kernel/qeventdispatcher_unix.cpp
index 3c7a48ac68..27efac6985 100644
--- a/src/corelib/kernel/qeventdispatcher_unix.cpp
+++ b/src/corelib/kernel/qeventdispatcher_unix.cpp
@@ -448,11 +448,7 @@ static timeval roundToMillisecond(timeval val)
 
     int us = val.tv_usec % 1000;
     val.tv_usec += 1000 - us;
-    if (val.tv_usec > 1000000) {
-        val.tv_usec -= 1000000;
-        ++val.tv_sec;
-    }
-    return val;
+    return normalizedTimeval(val);
 }
 
 /*