[kaffe] unix-jthreads timeout overflow fix
Jim Pick
jim at kaffe.org
Fri May 31 20:33:09 PDT 2002
Looks good, I put it in.
Cheers,
- Jim
On Fri, 2002-05-31 at 10:19, Timothy Stack wrote:
>
> hi,
>
> Attached is a fix for unix-jthreads that should better handle large
> timeout values. For example:
>
> synchronized( this )
> {
> this.wait(Long.MAX_VALUE);
> }
>
> eventually reaches this code:
>
> jtid->time = timeout + currentTime();
>
> which overflows and gives a bogus value.
>
> tim
> ----
>
> Index: jthread.c
> ===================================================================
> RCS file: /cvs/kaffe/kaffe/kaffe/kaffevm/systems/unix-jthreads/jthread.c,v
> retrieving revision 1.86
> diff -u -r1.86 jthread.c
> --- jthread.c 29 May 2002 19:46:24 -0000 1.86
> +++ jthread.c 31 May 2002 17:11:56 -0000
> @@ -255,26 +255,34 @@
> addToAlarmQ(jthread* jtid, jlong timeout)
> {
> jthread** tidp;
> + jlong ct;
>
> assert(intsDisabled());
>
> - jtid->flags |= THREAD_FLAGS_ALARM;
> -
> - /* Get absolute time */
> - jtid->time = timeout + currentTime();
> -
> - /* Find place in alarm list and insert it */
> - for (tidp = &alarmList; (*tidp) != 0; tidp = &(*tidp)->nextalarm) {
> - if ((*tidp)->time > jtid->time) {
> - break;
> + ct = currentTime();
> + if( (timeout + ct) > ct ) {
> + jtid->flags |= THREAD_FLAGS_ALARM;
> +
> + /* Get absolute time */
> + jtid->time = timeout + ct;
> +
> + /* Find place in alarm list and insert it */
> + for (tidp = &alarmList;
> + (*tidp) != 0;
> + tidp = &(*tidp)->nextalarm) {
> + if ((*tidp)->time > jtid->time) {
> + break;
> + }
> }
> - }
> - jtid->nextalarm = *tidp;
> - *tidp = jtid;
> -
> - /* If I'm head of alarm list, restart alarm */
> - if (tidp == &alarmList) {
> - MALARM(timeout);
> + jtid->nextalarm = *tidp;
> + *tidp = jtid;
> +
> + /* If I'm head of alarm list, restart alarm */
> + if (tidp == &alarmList) {
> + MALARM(timeout);
> + }
> + } else {
> + /* Huge timeout value, ignore it. */
> }
> }
>
> @@ -2216,8 +2224,13 @@
> * various building blocks for timeout system call functions
> */
> #define SET_DEADLINE(deadline, timeout) \
> - if (timeout != NOTIMEOUT) { \
> - deadline = timeout + currentTime(); \
> + if (timeout != NOTIMEOUT) { \
> + jlong ct = currentTime(); \
> + deadline = timeout + ct; \
> + if( deadline < ct ) { \
> + deadline = 0; \
> + timeout = NOTIMEOUT; \
> + } \
> }
>
> #define BREAK_IF_LATE(deadline, timeout) \
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