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glibc/sysdeps/unix/sysv/linux/timer_create.c
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/* 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; | |
} | |
} | |
} |