* src/threads/posix/thread-posix.cpp (threads_calc_absolute_time):

An attempt at improved integer overflow handling.

diff --git a/src/threads/posix/thread-posix.cpp b/src/threads/posix/thread-posix.cpp
index 40c59aa68c3b96e6f7263631bec314aaae2e9712..bcc25c9f137b8f6d765ab08195506ab18080b46f 100644 (file)
--- a/src/threads/posix/thread-posix.cpp
+++ b/src/threads/posix/thread-posix.cpp
@@ -27,6 +27,8 @@
 
 /* XXX cleanup these includes */
 
+#define __STDC_LIMIT_MACROS
+
 #include <stdlib.h>
 #include <string.h>
 #include <assert.h>
@@ -1455,20 +1457,26 @@ void threads_wait_with_timeout_relative(threadobject *thread, s8 millis,
 
 static void threads_calc_absolute_time(struct timespec *tm, s8 millis, s4 nanos)
 {
-       if ((millis != 0x7fffffffffffffffLLU) && (millis || nanos)) {
+       // (at least with GNU classpath) we know that 0 <= nanos <= 999999
+       do {
+               if (!millis && !nanos)
+                       break;
                struct timeval tv;
-               long nsec;
                gettimeofday(&tv, NULL);
-               tv.tv_sec += millis / 1000;
+               s8 secs = tv.tv_sec + millis / 1000;
+               if (secs > INT32_MAX)   // integer overflow
+                       break;
+               tv.tv_sec = secs;
                millis %= 1000;
-               nsec = tv.tv_usec * 1000 + (s4) millis * 1000000 + nanos;
+               long nsec = tv.tv_usec * 1000 + (s4) millis * 1000000 + nanos;
                tm->tv_sec = tv.tv_sec + nsec / 1000000000;
+               if (tm->tv_sec < tv.tv_sec) // integer overflow
+                       break;
                tm->tv_nsec = nsec % 1000000000;
-       }
-       else {
-               tm->tv_sec = 0;
-               tm->tv_nsec = 0;
-       }
+               return;
+       } while (0);
+       tm->tv_sec = 0;
+       tm->tv_nsec = 0;
 }