File: timer_create.c

package info (click to toggle)
glibc 2.24-10
  • links: PTS, VCS
  • area: main
  • in suites:
  • size: 223,412 kB
  • sloc: ansic: 991,967; asm: 261,800; sh: 10,385; makefile: 9,710; cpp: 4,169; python: 3,971; perl: 2,254; awk: 1,753; pascal: 1,521; yacc: 291; sed: 80
file content (176 lines) | stat: -rw-r--r-- 5,102 bytes parent folder | download | duplicates (5)
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
/* Copyright (C) 2003-2016 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, see <http://www.gnu.org/licenses/>.  */

#include <errno.h>
#include <pthread.h>
#include <signal.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <sysdep.h>
#include <internaltypes.h>
#include <nptl/pthreadP.h>
#include "kernel-posix-timers.h"
#include "kernel-posix-cpu-timers.h"


#ifdef timer_create_alias
# define timer_create timer_create_alias
#endif


int
timer_create (clockid_t clock_id, struct sigevent *evp, timer_t *timerid)
{
#undef timer_create
  {
    clockid_t syscall_clockid = (clock_id == CLOCK_PROCESS_CPUTIME_ID
				 ? MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED)
				 : clock_id == CLOCK_THREAD_CPUTIME_ID
				 ? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED)
				 : clock_id);

    /* If the user wants notification via a thread we need to handle
       this special.  */
    if (evp == NULL
	|| __builtin_expect (evp->sigev_notify != SIGEV_THREAD, 1))
      {
	struct sigevent local_evp;

	/* We avoid allocating too much memory by basically
	   using struct timer as a derived class with the
	   first two elements being in the superclass.  We only
	   need these two elements here.  */
	struct timer *newp = (struct timer *) malloc (offsetof (struct timer,
								thrfunc));
	if (newp == NULL)
	  /* No more memory.  */
	  return -1;

	if (evp == NULL)
	  {
	    /* The kernel has to pass up the timer ID which is a
	       userlevel object.  Therefore we cannot leave it up to
	       the kernel to determine it.  */
	    local_evp.sigev_notify = SIGEV_SIGNAL;
	    local_evp.sigev_signo = SIGALRM;
	    local_evp.sigev_value.sival_ptr = newp;

	    evp = &local_evp;
	  }

	kernel_timer_t ktimerid;
	int retval = INLINE_SYSCALL (timer_create, 3, syscall_clockid, evp,
				     &ktimerid);

	if (retval != -1)
	  {
	    newp->sigev_notify = (evp != NULL
				  ? evp->sigev_notify : SIGEV_SIGNAL);
	    newp->ktimerid = ktimerid;

	    *timerid = (timer_t) newp;
	  }
	else
	  {
	    /* Cannot allocate the timer, fail.  */
	    free (newp);
	    retval = -1;
	  }

	return retval;
      }
    else
      {
	/* Create the helper thread.  */
	pthread_once (&__helper_once, __start_helper_thread);
	if (__helper_tid == 0)
	  {
	    /* No resources to start the helper thread.  */
	    __set_errno (EAGAIN);
	    return -1;
	  }

	struct timer *newp;
	newp = (struct timer *) malloc (sizeof (struct timer));
	if (newp == NULL)
	  return -1;

	/* Copy the thread parameters the user provided.  */
	newp->sival = evp->sigev_value;
	newp->thrfunc = evp->sigev_notify_function;
	newp->sigev_notify = SIGEV_THREAD;

	/* We cannot simply copy the thread attributes since the
	   implementation might keep internal information for
	   each instance.  */
	(void) pthread_attr_init (&newp->attr);
	if (evp->sigev_notify_attributes != NULL)
	  {
	    struct pthread_attr *nattr;
	    struct pthread_attr *oattr;

	    nattr = (struct pthread_attr *) &newp->attr;
	    oattr = (struct pthread_attr *) evp->sigev_notify_attributes;

	    nattr->schedparam = oattr->schedparam;
	    nattr->schedpolicy = oattr->schedpolicy;
	    nattr->flags = oattr->flags;
	    nattr->guardsize = oattr->guardsize;
	    nattr->stackaddr = oattr->stackaddr;
	    nattr->stacksize = oattr->stacksize;
	  }

	/* In any case set the detach flag.  */
	(void) pthread_attr_setdetachstate (&newp->attr,
					    PTHREAD_CREATE_DETACHED);

	/* Create the event structure for the kernel timer.  */
	struct sigevent sev =
	  { .sigev_value.sival_ptr = newp,
	    .sigev_signo = SIGTIMER,
	    .sigev_notify = SIGEV_SIGNAL | SIGEV_THREAD_ID,
	    ._sigev_un = { ._pad = { [0] = __helper_tid } } };

	/* Create the timer.  */
	INTERNAL_SYSCALL_DECL (err);
	int res;
	res = INTERNAL_SYSCALL (timer_create, err, 3,
				syscall_clockid, &sev, &newp->ktimerid);
	if (! INTERNAL_SYSCALL_ERROR_P (res, err))
	  {
	    /* Add to the queue of active timers with thread
	       delivery.  */
	    pthread_mutex_lock (&__active_timer_sigev_thread_lock);
	    newp->next = __active_timer_sigev_thread;
	    __active_timer_sigev_thread = newp;
	    pthread_mutex_unlock (&__active_timer_sigev_thread_lock);

	    *timerid = (timer_t) newp;
	    return 0;
	  }

	/* Free the resources.  */
	free (newp);

	__set_errno (INTERNAL_SYSCALL_ERRNO (res, err));

	return -1;
      }
  }
}