avoid all malloc/free in timer creation/destruction

instead of allocating a userspace structure for signal-based timers,
simply use the kernel timer id. we use the fact that thread pointers
will always be zero in the low bit (actually more) to encode integer
timerid values as pointers.

also, this change ensures that the timer_destroy syscall has completed
before the library timer_destroy function returns, in case it matters.

1 files changed, 7 insertions, 6 deletions

diff --git a/src/time/timer_delete.c b/src/time/timer_delete.c
index caf04895..437de2e0 100644
--- a/src/time/timer_delete.c
+++ b/src/time/timer_delete.c
@@ -3,10 +3,11 @@
 
 int timer_delete(timer_t t)
 {
-	if (t->thread) pthread_cancel(t->thread);
-	else {
-		__syscall(SYS_timer_delete, t->timerid);
-		free(t);
-	}
-	return 0;
+	pthread_t td = 0;
+	int r;
+	if ((uintptr_t)t & 1) t = (void *)((unsigned long)t / 2);
+	else td = t, t = td->result;
+	r = __syscall(SYS_timer_delete, (long)t);
+	if (td) pthread_cancel(td);
+	return r;
 }