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f3c13160 | 1 | /* low level locking for pthread library. Generic futex-using version. |
b168057a | 2 | Copyright (C) 2003-2015 Free Software Foundation, Inc. |
f3c13160 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 | |
59ba27a6 PE |
17 | License along with the GNU C Library; if not, see |
18 | <http://www.gnu.org/licenses/>. */ | |
f3c13160 RM |
19 | |
20 | #include <errno.h> | |
21 | #include <sysdep.h> | |
22 | #include <lowlevellock.h> | |
23 | #include <sys/time.h> | |
05087fbb | 24 | #include <atomic.h> |
f3c13160 RM |
25 | |
26 | void | |
e51deae7 | 27 | __lll_lock_wait_private (int *futex) |
f3c13160 | 28 | { |
c012be6f | 29 | if (*futex == 2) |
d52c62df | 30 | lll_futex_wait (futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */ |
c012be6f UD |
31 | |
32 | while (atomic_exchange_acq (futex, 2) != 0) | |
d52c62df | 33 | lll_futex_wait (futex, 2, LLL_PRIVATE); /* Wait if *futex == 2. */ |
e51deae7 UD |
34 | } |
35 | ||
36 | ||
467d1345 | 37 | /* These functions don't get included in libc.so */ |
ce9f10f7 | 38 | #if IS_IN (libpthread) |
e51deae7 UD |
39 | void |
40 | __lll_lock_wait (int *futex, int private) | |
41 | { | |
c012be6f | 42 | if (*futex == 2) |
d52c62df | 43 | lll_futex_wait (futex, 2, private); /* Wait if *futex == 2. */ |
c012be6f UD |
44 | |
45 | while (atomic_exchange_acq (futex, 2) != 0) | |
d52c62df | 46 | lll_futex_wait (futex, 2, private); /* Wait if *futex == 2. */ |
f3c13160 | 47 | } |
f3c13160 RM |
48 | |
49 | ||
50 | int | |
e51deae7 | 51 | __lll_timedlock_wait (int *futex, const struct timespec *abstime, int private) |
f3c13160 | 52 | { |
f3c13160 | 53 | /* Reject invalid timeouts. */ |
31195be2 | 54 | if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) |
f3c13160 RM |
55 | return EINVAL; |
56 | ||
c012be6f UD |
57 | /* Try locking. */ |
58 | while (atomic_exchange_acq (futex, 2) != 0) | |
f3c13160 RM |
59 | { |
60 | struct timeval tv; | |
f3c13160 RM |
61 | |
62 | /* Get the current time. */ | |
bd0fa4ce | 63 | (void) __gettimeofday (&tv, NULL); |
f3c13160 RM |
64 | |
65 | /* Compute relative timeout. */ | |
c012be6f | 66 | struct timespec rt; |
bd0fa4ce UD |
67 | rt.tv_sec = abstime->tv_sec - tv.tv_sec; |
68 | rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; | |
69 | if (rt.tv_nsec < 0) | |
f3c13160 | 70 | { |
bd0fa4ce UD |
71 | rt.tv_nsec += 1000000000; |
72 | --rt.tv_sec; | |
f3c13160 RM |
73 | } |
74 | ||
c012be6f UD |
75 | if (rt.tv_sec < 0) |
76 | return ETIMEDOUT; | |
f3c13160 | 77 | |
d52c62df | 78 | /* If *futex == 2, wait until woken or timeout. */ |
c012be6f | 79 | lll_futex_timed_wait (futex, 2, &rt, private); |
bd0fa4ce | 80 | } |
f3c13160 | 81 | |
c012be6f | 82 | return 0; |
f3c13160 | 83 | } |
f3c13160 RM |
84 | |
85 | ||
d52c62df TR |
86 | /* The kernel notifies a process which uses CLONE_CHILD_CLEARTID via futex |
87 | wake-up when the clone terminates. The memory location contains the | |
88 | thread ID while the clone is running and is reset to zero by the kernel | |
89 | afterwards. The kernel up to version 3.16.3 does not use the private futex | |
90 | operations for futex wake-up when the clone terminates. */ | |
f3c13160 RM |
91 | int |
92 | __lll_timedwait_tid (int *tidp, const struct timespec *abstime) | |
93 | { | |
94 | int tid; | |
f3c13160 | 95 | |
31195be2 | 96 | if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000) |
f3c13160 RM |
97 | return EINVAL; |
98 | ||
99 | /* Repeat until thread terminated. */ | |
100 | while ((tid = *tidp) != 0) | |
101 | { | |
102 | struct timeval tv; | |
103 | struct timespec rt; | |
f3c13160 RM |
104 | |
105 | /* Get the current time. */ | |
bd0fa4ce | 106 | (void) __gettimeofday (&tv, NULL); |
f3c13160 RM |
107 | |
108 | /* Compute relative timeout. */ | |
bd0fa4ce UD |
109 | rt.tv_sec = abstime->tv_sec - tv.tv_sec; |
110 | rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000; | |
111 | if (rt.tv_nsec < 0) | |
f3c13160 | 112 | { |
bd0fa4ce UD |
113 | rt.tv_nsec += 1000000000; |
114 | --rt.tv_sec; | |
f3c13160 RM |
115 | } |
116 | ||
117 | /* Already timed out? */ | |
bd0fa4ce UD |
118 | if (rt.tv_sec < 0) |
119 | return ETIMEDOUT; | |
f3c13160 | 120 | |
d52c62df TR |
121 | /* If *tidp == tid, wait until thread terminates or the wait times out. |
122 | The kernel up to version 3.16.3 does not use the private futex | |
123 | operations for futex wake-up when the clone terminates. | |
124 | */ | |
835abc5c | 125 | if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT) |
bd0fa4ce | 126 | return ETIMEDOUT; |
f3c13160 RM |
127 | } |
128 | ||
bd0fa4ce | 129 | return 0; |
f3c13160 | 130 | } |
f3c13160 | 131 | #endif |