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68c97aef | 1 | /* Timed low level locking for pthread library. Generic futex-using version. |
bfff8b1b | 2 | Copyright (C) 2003-2017 Free Software Foundation, Inc. |
68c97aef RM |
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_timedlock_wait (int *futex, const struct timespec *abstime, int private) | |
28 | { | |
29 | /* Reject invalid timeouts. */ | |
30 | if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) | |
31 | return EINVAL; | |
32 | ||
33 | /* Try locking. */ | |
34 | while (atomic_exchange_acq (futex, 2) != 0) | |
35 | { | |
36 | struct timeval tv; | |
37 | ||
38 | /* Get the current time. */ | |
39 | (void) __gettimeofday (&tv, NULL); | |
40 | ||
41 | /* Compute relative timeout. */ | |
42 | struct timespec rt; | |
43 | rt.tv_sec = abstime->tv_sec - tv.tv_sec; | |
44 | rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; | |
45 | if (rt.tv_nsec < 0) | |
46 | { | |
47 | rt.tv_nsec += 1000000000; | |
48 | --rt.tv_sec; | |
49 | } | |
50 | ||
51 | if (rt.tv_sec < 0) | |
52 | return ETIMEDOUT; | |
53 | ||
54 | /* If *futex == 2, wait until woken or timeout. */ | |
55 | lll_futex_timed_wait (futex, 2, &rt, private); | |
56 | } | |
57 | ||
58 | return 0; | |
59 | } |