1 /* Copyright (C) 2003, 2004, 2007, 2008 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
4
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
9
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
14
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
18
19 #include <assert.h>
20 #include <errno.h>
21 #include <stdbool.h>
22 #include <time.h>
23 #include <sysdep.h>
24 #include "pthreadP.h"
25 #include <bits/kernel-features.h>
26
27
28 int
pthread_condattr_setclock(pthread_condattr_t * attr,clockid_t clock_id)29 pthread_condattr_setclock (
30 pthread_condattr_t *attr,
31 clockid_t clock_id)
32 {
33 /* Only a few clocks are allowed. CLOCK_REALTIME is always allowed.
34 CLOCK_MONOTONIC only if the kernel has the necessary support. */
35 if (clock_id == CLOCK_MONOTONIC)
36 {
37 #ifndef __ASSUME_POSIX_TIMERS
38 # ifdef __NR_clock_getres
39 /* Check whether the clock is available. */
40 static int avail;
41
42 if (avail == 0)
43 {
44 struct timespec ts;
45
46 INTERNAL_SYSCALL_DECL (err);
47 int val;
48 val = INTERNAL_SYSCALL (clock_getres, err, 2, CLOCK_MONOTONIC, &ts);
49 avail = INTERNAL_SYSCALL_ERROR_P (val, err) ? -1 : 1;
50 }
51
52 if (avail < 0)
53 # endif
54 /* Not available. */
55 return EINVAL;
56 #endif
57 }
58 else if (clock_id != CLOCK_REALTIME)
59 /* If more clocks are allowed some day the storing of the clock ID
60 in the pthread_cond_t structure needs to be adjusted. */
61 return EINVAL;
62
63 /* Make sure the value fits in the bits we reserved. */
64 assert (clock_id < (1 << COND_NWAITERS_SHIFT));
65
66 int *valuep = &((struct pthread_condattr *) attr)->value;
67
68 *valuep = ((*valuep & ~(((1 << COND_NWAITERS_SHIFT) - 1) << 1))
69 | (clock_id << 1));
70
71 return 0;
72 }
73