summaryrefslogtreecommitdiff
path: root/libpthread/nptl/sysdeps/unix/sysv/linux/arm/lowlevellock.c
blob: cd4213573e3788fda36f88b462603aa013f2aeb4 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
/* low level locking for pthread library.  Generic futex-using version.
   Copyright (C) 2003, 2005, 2007 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <sysdep.h>
#include <lowlevellock.h>
#include <sys/time.h>
#include <tls.h>

void
#ifndef IS_IN_libpthread
weak_function
#endif
__lll_lock_wait_private (int *futex)
{
  do
    {
      int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1);
      if (oldval != 0)
	lll_futex_wait (futex, 2, LLL_PRIVATE);
    }
  while (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0);
}


/* These functions don't get included in libc.so  */
#ifdef IS_IN_libpthread
void
__lll_lock_wait (int *futex, int private)
{
  do
    {
      int oldval = atomic_compare_and_exchange_val_acq (futex, 2, 1);
      if (oldval != 0)
	lll_futex_wait (futex, 2, private);
    }
  while (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0);
}


int
__lll_timedlock_wait (int *futex, const struct timespec *abstime, int private)
{
  struct timespec rt;

  /* Reject invalid timeouts.  */
  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
    return EINVAL;

  /* Upgrade the lock.  */
  if (atomic_exchange_acq (futex, 2) == 0)
    return 0;

  do
    {
      struct timeval tv;

      /* Get the current time.  */
      (void) gettimeofday (&tv, NULL);

      /* Compute relative timeout.  */
      rt.tv_sec = abstime->tv_sec - tv.tv_sec;
      rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
      if (rt.tv_nsec < 0)
	{
	  rt.tv_nsec += 1000000000;
	  --rt.tv_sec;
	}

      /* Already timed out?  */
      if (rt.tv_sec < 0)
	return ETIMEDOUT;

      // XYZ: Lost the lock to check whether it was private.
      lll_futex_timed_wait (futex, 2, &rt, private);
    }
  while (atomic_compare_and_exchange_bool_acq (futex, 2, 0) != 0);

  return 0;
}


int
__lll_timedwait_tid (int *tidp, const struct timespec *abstime)
{
  int tid;

  if (abstime->tv_nsec < 0 || abstime->tv_nsec >= 1000000000)
    return EINVAL;

  /* Repeat until thread terminated.  */
  while ((tid = *tidp) != 0)
    {
      struct timeval tv;
      struct timespec rt;

      /* Get the current time.  */
      (void) gettimeofday (&tv, NULL);

      /* Compute relative timeout.  */
      rt.tv_sec = abstime->tv_sec - tv.tv_sec;
      rt.tv_nsec = abstime->tv_nsec - tv.tv_usec * 1000;
      if (rt.tv_nsec < 0)
	{
	  rt.tv_nsec += 1000000000;
	  --rt.tv_sec;
	}

      /* Already timed out?  */
      if (rt.tv_sec < 0)
	return ETIMEDOUT;

      /* Wait until thread terminates.  */
      // XYZ: Lost the lock to check whether it was private.
      if (lll_futex_timed_wait (tidp, tid, &rt, LLL_SHARED) == -ETIMEDOUT)
	return ETIMEDOUT;
    }

  return 0;
}
#endif