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Commit d6b37d83 authored by Daniel Stenberg's avatar Daniel Stenberg
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curlx_tvdiff: handle 32bit time_t overflows

On 32bit systems, make sure we don't overflow and return funky values
for very large time differences.

Reported-by: Anders Bakken

Closes #646
parent d202fbcc
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......@@ -5,7 +5,7 @@
* | (__| |_| | _ <| |___
* \___|\___/|_| \_\_____|
*
* Copyright (C) 1998 - 2015, Daniel Stenberg, <daniel@haxx.se>, et al.
* Copyright (C) 1998 - 2016, Daniel Stenberg, <daniel@haxx.se>, et al.
*
* This software is licensed as described in the file COPYING, which
* you should have received as part of this distribution. The terms
......@@ -113,10 +113,18 @@ struct timeval curlx_tvnow(void)
* Make sure that the first argument is the more recent time, as otherwise
* we'll get a weird negative time-diff back...
*
* Returns: the time difference in number of milliseconds.
* Returns: the time difference in number of milliseconds. For large diffs it
* returns 0x7fffffff on 32bit time_t systems.
*/
long curlx_tvdiff(struct timeval newer, struct timeval older)
{
#if SIZEOF_TIME_T < 8
/* for 32bit time_t systems, add a precaution to avoid overflow for really
big time differences */
time_t diff = newer.tv_sec-older.tv_sec;
if(diff >= (0x7fffffff/1000))
return 0x7fffffff;
#endif
return (newer.tv_sec-older.tv_sec)*1000+
(long)(newer.tv_usec-older.tv_usec)/1000;
}
......
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