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
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
|
/* Copyright (C) 2003, 2004, 2005, 2006 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2003.
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; see the file COPYING.LIB. If not,
write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA. */
#include <errno.h>
#include <setjmp.h>
#include <signal.h>
#include <stdbool.h>
#include <sysdep.h>
#include <kernel-features.h>
#include <nptl/pthreadP.h>
#include "kernel-posix-timers.h"
struct thread_start_data
{
void (*thrfunc) (sigval_t);
sigval_t sival;
};
#ifdef __NR_timer_create
/* Helper thread to call the user-provided function. */
static void *
timer_sigev_thread (void *arg)
{
/* The parent thread has all signals blocked. This is a bit
surprising for user code, although valid. We unblock all
signals. */
sigset_t ss;
sigemptyset (&ss);
INTERNAL_SYSCALL_DECL (err);
INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, NULL, _NSIG / 8);
struct thread_start_data *td = (struct thread_start_data *) arg;
void (*thrfunc) (sigval_t) = td->thrfunc;
sigval_t sival = td->sival;
/* The TD object was allocated in timer_helper_thread. */
free (td);
/* Call the user-provided function. */
thrfunc (sival);
return NULL;
}
/* Helper function to support starting threads for SIGEV_THREAD. */
static void *
timer_helper_thread (void *arg)
{
/* Wait for the SIGTIMER signal, allowing the setXid signal, and
none else. */
sigset_t ss;
sigemptyset (&ss);
__sigaddset (&ss, SIGTIMER);
/* Endless loop of waiting for signals. The loop is only ended when
the thread is canceled. */
while (1)
{
siginfo_t si;
/* sigwaitinfo cannot be used here, since it deletes
SIGCANCEL == SIGTIMER from the set. */
int oldtype = LIBC_CANCEL_ASYNC ();
/* XXX The size argument hopefully will have to be changed to the
real size of the user-level sigset_t. */
int result = INLINE_SYSCALL (rt_sigtimedwait, 4, &ss, &si, NULL,
_NSIG / 8);
LIBC_CANCEL_RESET (oldtype);
if (result > 0)
{
if (si.si_code == SI_TIMER)
{
struct timer *tk = (struct timer *) si.si_ptr;
struct thread_start_data *td = malloc (sizeof (*td));
/* There is not much we can do if the allocation fails. */
if (td != NULL)
{
/* That is the signal we are waiting for. */
td->thrfunc = tk->thrfunc;
td->sival = tk->sival;
pthread_t th;
(void) pthread_create (&th, &tk->attr, timer_sigev_thread,
td);
}
}
else if (si.si_code == SI_TKILL)
/* The thread is canceled. */
pthread_exit (NULL);
}
}
}
/* Control variable for helper thread creation. */
pthread_once_t __helper_once attribute_hidden;
/* TID of the helper thread. */
pid_t __helper_tid attribute_hidden;
/* Reset variables so that after a fork a new helper thread gets started. */
static void
reset_helper_control (void)
{
__helper_once = PTHREAD_ONCE_INIT;
__helper_tid = 0;
}
void
attribute_hidden
__start_helper_thread (void)
{
/* The helper thread needs only very little resources
and should go away automatically when canceled. */
pthread_attr_t attr;
(void) pthread_attr_init (&attr);
(void) pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN);
/* Block all signals in the helper thread but SIGSETXID. To do this
thoroughly we temporarily have to block all signals here. The
helper can lose wakeups if SIGCANCEL is not blocked throughout,
but sigfillset omits it SIGSETXID. So, we add SIGCANCEL back
explicitly here. */
sigset_t ss;
sigset_t oss;
sigfillset (&ss);
__sigaddset (&ss, SIGCANCEL);
INTERNAL_SYSCALL_DECL (err);
INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &ss, &oss, _NSIG / 8);
/* Create the helper thread for this timer. */
pthread_t th;
int res = pthread_create (&th, &attr, timer_helper_thread, NULL);
if (res == 0)
/* We managed to start the helper thread. */
__helper_tid = ((struct pthread *) th)->tid;
/* Restore the signal mask. */
INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_SETMASK, &oss, NULL,
_NSIG / 8);
/* No need for the attribute anymore. */
(void) pthread_attr_destroy (&attr);
/* We have to make sure that after fork()ing a new helper thread can
be created. */
pthread_atfork (NULL, NULL, reset_helper_control);
}
#endif
#ifndef __ASSUME_POSIX_TIMERS
# include <nptl/sysdeps/pthread/timer_routines.c>
#endif
|
