1 | /* Timed low level locking for pthread library. Generic futex-using version. |
2 | Copyright (C) 2003-2019 Free Software Foundation, Inc. |
3 | This file is part of the GNU C Library. |
4 | Contributed by Paul Mackerras <paulus@au.ibm.com>, 2003. |
5 | |
6 | The GNU C Library is free software; you can redistribute it and/or |
7 | modify it under the terms of the GNU Lesser General Public |
8 | License as published by the Free Software Foundation; either |
9 | version 2.1 of the License, or (at your option) any later version. |
10 | |
11 | The GNU C Library is distributed in the hope that it will be useful, |
12 | but WITHOUT ANY WARRANTY; without even the implied warranty of |
13 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
14 | Lesser General Public License for more details. |
15 | |
16 | You should have received a copy of the GNU Lesser General Public |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ |
19 | |
20 | #include <atomic.h> |
21 | #include <errno.h> |
22 | #include <lowlevellock.h> |
23 | #include <sys/time.h> |
24 | |
25 | |
26 | int |
27 | __lll_clocklock_wait (int *futex, clockid_t clockid, |
28 | const struct timespec *abstime, int private) |
29 | { |
30 | /* Reject invalid timeouts. */ |
31 | if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) |
32 | return EINVAL; |
33 | |
34 | /* Try locking. */ |
35 | while (atomic_exchange_acq (futex, 2) != 0) |
36 | { |
37 | struct timespec ts; |
38 | |
39 | /* Get the current time. This can only fail if clockid is not |
40 | valid. */ |
41 | if (__glibc_unlikely (__clock_gettime (clockid, &ts) != 0)) |
42 | return EINVAL; |
43 | |
44 | /* Compute relative timeout. */ |
45 | struct timespec rt; |
46 | rt.tv_sec = abstime->tv_sec - ts.tv_sec; |
47 | rt.tv_nsec = abstime->tv_nsec - ts.tv_nsec; |
48 | if (rt.tv_nsec < 0) |
49 | { |
50 | rt.tv_nsec += 1000000000; |
51 | --rt.tv_sec; |
52 | } |
53 | |
54 | if (rt.tv_sec < 0) |
55 | return ETIMEDOUT; |
56 | |
57 | /* If *futex == 2, wait until woken or timeout. */ |
58 | lll_futex_timed_wait (futex, 2, &rt, private); |
59 | } |
60 | |
61 | return 0; |
62 | } |
63 | |