1/* Copyright (C) 2003-2023 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public License as
6 published by the Free Software Foundation; either version 2.1 of the
7 License, or (at your option) any later version.
8
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
13
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; see the file COPYING.LIB. If
16 not, see <https://www.gnu.org/licenses/>. */
17
18#include <pthread.h>
19#include <setjmp.h>
20#include <signal.h>
21#include <sys/types.h>
22
23
24/* Nonzero if the system calls are not available. */
25extern int __no_posix_timers attribute_hidden;
26
27/* Callback to start helper thread. */
28extern void __timer_start_helper_thread (void) attribute_hidden;
29
30/* Control variable for helper thread creation. */
31extern pthread_once_t __timer_helper_once attribute_hidden;
32
33/* Called from fork so that the new subprocess re-creates the
34 notification thread if necessary. */
35void __timer_fork_subprocess (void) attribute_hidden;
36
37/* TID of the helper thread. */
38extern pid_t __timer_helper_tid attribute_hidden;
39
40/* List of active SIGEV_THREAD timers. */
41extern struct timer *__timer_active_sigev_thread attribute_hidden;
42
43/* Lock for __timer_active_sigev_thread. */
44extern pthread_mutex_t __timer_active_sigev_thread_lock attribute_hidden;
45
46extern __typeof (timer_create) __timer_create;
47libc_hidden_proto (__timer_create)
48extern __typeof (timer_delete) __timer_delete;
49libc_hidden_proto (__timer_delete)
50extern __typeof (timer_getoverrun) __timer_getoverrun;
51libc_hidden_proto (__timer_getoverrun)
52
53/* Type of timers in the kernel. */
54typedef int kernel_timer_t;
55
56/* Internal representation of SIGEV_THREAD timer. */
57struct timer
58{
59 kernel_timer_t ktimerid;
60
61 void (*thrfunc) (sigval_t);
62 sigval_t sival;
63 pthread_attr_t attr;
64
65 /* Next element in list of active SIGEV_THREAD timers. */
66 struct timer *next;
67};
68
69
70/* For !SIGEV_THREAD, the resulting 'timer_t' is the returned kernel timer
71 identifer (kernel_timer_t), while for SIGEV_THREAD it uses the fact malloc
72 returns at least _Alignof (max_align_t) pointers plus that valid
73 kernel_timer_t are always positive to set the MSB bit of the returned
74 'timer_t' to indicate the timer handles a SIGEV_THREAD. */
75
76static inline timer_t
77kernel_timer_to_timerid (kernel_timer_t ktimerid)
78{
79 return (timer_t) ((intptr_t) ktimerid);
80}
81
82static inline timer_t
83timer_to_timerid (struct timer *ptr)
84{
85 return (timer_t) (INTPTR_MIN | (uintptr_t) ptr >> 1);
86}
87
88static inline bool
89timer_is_sigev_thread (timer_t timerid)
90{
91 return (intptr_t) timerid < 0;
92}
93
94static inline struct timer *
95timerid_to_timer (timer_t timerid)
96{
97 return (struct timer *)((uintptr_t) timerid << 1);
98}
99
100static inline kernel_timer_t
101timerid_to_kernel_timer (timer_t timerid)
102{
103 if (timer_is_sigev_thread (timerid))
104 return timerid_to_timer (timerid)->ktimerid;
105 else
106 return (kernel_timer_t) ((uintptr_t) timerid);
107}
108
109/* New targets use int instead of timer_t. The difference only
110 matters on 64-bit targets. */
111#include <timer_t_was_int_compat.h>
112
113#if TIMER_T_WAS_INT_COMPAT
114# define OLD_TIMER_MAX 256
115extern timer_t __timer_compat_list[OLD_TIMER_MAX];
116#endif
117