unify and overhaul timed futex waits

new features:

- FUTEX_WAIT_BITSET op will be used for timed waits if available. this
  saves a call to clock_gettime.

- error checking for the timespec struct is now inside __timedwait so
  it doesn't need to be duplicated everywhere. cond_timedwait still
  needs to duplicate it to avoid unlocking the mutex, though.

- pushing and popping the cancellation handler is delegated to
  __timedwait, and cancellable/non-cancellable waits are unified.

1 files changed, 39 insertions, 14 deletions

diff --git a/src/thread/__timedwait.c b/src/thread/__timedwait.c
index b1d3af23..931675eb 100644
--- a/src/thread/__timedwait.c
+++ b/src/thread/__timedwait.c
@@ -1,23 +1,48 @@
+#include <pthread.h>
 #include <time.h>
 #include <errno.h>
 #include "futex.h"
 #include "syscall.h"
 
-int __timedwait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, int priv)
+static int do_wait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, int cp, int priv)
 {
-	int r;
-	struct timespec to;
-	if (at) {
-		clock_gettime(clk, &to);
-		to.tv_sec = at->tv_sec - to.tv_sec;
-		if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
-			to.tv_sec--;
-			to.tv_nsec += 1000000000;
-		}
-		if (to.tv_sec < 0) return ETIMEDOUT;
+	int r, flag = 0;
+	struct timespec to, *top=0;
+
+	if (!at) goto notimeout;
+	if (at->tv_nsec >= 1000000000UL)
+		return EINVAL;
+	if (clk == CLOCK_REALTIME || clk == CLOCK_MONOTONIC) {
+		if (clk == CLOCK_REALTIME) flag = FUTEX_CLOCK_REALTIME;
+		if (cp) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT_BITSET|flag, val, at, 0, -1);
+		else r = -__syscall(SYS_futex, addr, FUTEX_WAIT_BITSET|flag, val, at, 0, -1);
+		if (r != ENOSYS) goto done;
 	}
-	if (priv) priv = 128; priv=0;
-	r = -__syscall(SYS_futex, (long)addr, FUTEX_WAIT | priv, val, at ? (long)&to : 0);
-	if (r == ETIMEDOUT || r == EINTR) return r;
+	if (clock_gettime(clk, &to)) return EINVAL;
+	to.tv_sec = at->tv_sec - to.tv_sec;
+	if ((to.tv_nsec = at->tv_nsec - to.tv_nsec) < 0) {
+		to.tv_sec--;
+		to.tv_nsec += 1000000000;
+	}
+	if (to.tv_sec < 0) return ETIMEDOUT;
+	top = &to;
+notimeout:
+	if (cp) r = -__syscall_cp(SYS_futex, addr, FUTEX_WAIT, val, top);
+	else r = -__syscall(SYS_futex, addr, FUTEX_WAIT, val, top);
+done:
+	if (r == EINTR || r == EINVAL || r == ETIMEDOUT) return r;
 	return 0;
 }
+
+int __timedwait(volatile int *addr, int val, clockid_t clk, const struct timespec *at, void (*cleanup)(void *), void *arg, int priv)
+{
+	int r;
+	if (cleanup) {
+		pthread_cleanup_push(cleanup, arg);
+		r = do_wait(addr, val, clk, at, 1, priv);
+		pthread_cleanup_pop(0);
+	} else {
+		r = do_wait(addr, val, clk, at, 0, priv);
+	}
+	return r;
+}