From: Rich Felker <dalias@aerifal.cx>
Date: Wed, 3 Aug 2011 01:18:43 +0000 (-0400)
Subject: correctly handle old kernels without FUTEX_WAIT_BITSET
X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=commitdiff_plain;h=4717bfec708d264111f70f37850ffc09238c4bd5;hp=bdd893377fe65519fae90948cd8f3c635757eaba

correctly handle old kernels without FUTEX_WAIT_BITSET

futex returns EINVAL, not ENOSYS, when op is not supported.
unfortunately this looks just like EINVAL from other causes, and we
end up running the fallback code and getting EINVAL again. fortunately
this case should be rare since correct code should not generate EINVAL
anyway.
---

diff --git a/src/thread/__timedwait.c b/src/thread/__timedwait.c
index 931675eb..0444d39f 100644
--- a/src/thread/__timedwait.c
+++ b/src/thread/__timedwait.c
@@ -16,7 +16,7 @@ static int do_wait(volatile int *addr, int val, clockid_t clk, const struct time
 		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 (r != EINVAL) goto done;
 	}
 	if (clock_gettime(clk, &to)) return EINVAL;
 	to.tv_sec = at->tv_sec - to.tv_sec;