nptl/sysdeps/unix/sysv/linux/timer_create.c

   1 /* Copyright (C) 2003,2004, 2007 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 License as
   7    published by the Free Software Foundation; either version 2.1 of the
   8    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; see the file COPYING.LIB.  If not,
  17    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  18    Boston, MA 02111-1307, USA.  */
  19
  20 #include <errno.h>
  21 #include <pthread.h>
  22 #include <signal.h>
  23 #include <stdlib.h>
  24 #include <string.h>
  25 #include <time.h>
  26 #include <sysdep.h>
  27 #include <kernel-features.h>
  28 #include <internaltypes.h>
  29 #include <nptl/pthreadP.h>
  30 #include "kernel-posix-timers.h"
  31 #include "kernel-posix-cpu-timers.h"
  32
  33
  34 #ifdef __NR_timer_create
  35 # ifndef __ASSUME_POSIX_TIMERS
  36 static int compat_timer_create (clockid_t clock_id, struct sigevent *evp,
  37                                 timer_t *timerid);
  38 #  define timer_create static compat_timer_create
  39 #  include <nptl/sysdeps/pthread/timer_create.c>
  40 #  undef timer_create
  41
  42 /* Nonzero if the system calls are not available.  */
  43 int __no_posix_timers attribute_hidden;
  44 # endif
  45
  46 # ifdef timer_create_alias
  47 #  define timer_create timer_create_alias
  48 # endif
  49
  50
  51 int
  52 timer_create (clock_id, evp, timerid)
  53      clockid_t clock_id;
  54      struct sigevent *evp;
  55      timer_t *timerid;
  56 {
  57 # undef timer_create
  58 # ifndef __ASSUME_POSIX_TIMERS
  59   if  (__no_posix_timers >= 0)
  60 # endif
  61     {
  62       clockid_t syscall_clockid = (clock_id == CLOCK_PROCESS_CPUTIME_ID
  63                                    ? MAKE_PROCESS_CPUCLOCK (0, CPUCLOCK_SCHED)
  64                                    : clock_id == CLOCK_THREAD_CPUTIME_ID
  65                                    ? MAKE_THREAD_CPUCLOCK (0, CPUCLOCK_SCHED)
  66                                    : clock_id);
  67
  68       /* If the user wants notification via a thread we need to handle
  69          this special.  */
  70       if (evp == NULL
  71           || __builtin_expect (evp->sigev_notify != SIGEV_THREAD, 1))
  72         {
  73           struct sigevent local_evp;
  74
  75           /* We avoid allocating too much memory by basically
  76              using struct timer as a derived class with the
  77              first two elements being in the superclass.  We only
  78              need these two elements here.  */
  79           struct timer *newp = (struct timer *) malloc (offsetof (struct timer,
  80                                                                   thrfunc));
  81           if (newp == NULL)
  82             /* No more memory.  */
  83             return -1;
  84
  85           if (evp == NULL)
  86             {
  87               /* The kernel has to pass up the timer ID which is a
  88                  userlevel object.  Therefore we cannot leave it up to
  89                  the kernel to determine it.  */
  90               local_evp.sigev_notify = SIGEV_SIGNAL;
  91               local_evp.sigev_signo = SIGALRM;
  92               local_evp.sigev_value.sival_ptr = newp;
  93
  94               evp = &local_evp;
  95             }
  96
  97           kernel_timer_t ktimerid;
  98           int retval = INLINE_SYSCALL (timer_create, 3, syscall_clockid, evp,
  99                                        &ktimerid);
 100
 101 # ifndef __ASSUME_POSIX_TIMERS
 102           if (retval != -1 || errno != ENOSYS)
 103 # endif
 104             {
 105 # ifndef __ASSUME_POSIX_TIMERS
 106               __no_posix_timers = 1;
 107 # endif
 108
 109               if (retval != -1)
 110                 {
 111                   newp->sigev_notify = (evp != NULL
 112                                         ? evp->sigev_notify : SIGEV_SIGNAL);
 113                   newp->ktimerid = ktimerid;
 114
 115                   *timerid = (timer_t) newp;
 116                 }
 117               else
 118                 {
 119                   /* Cannot allocate the timer, fail.  */
 120                   free (newp);
 121                   retval = -1;
 122                 }
 123
 124               return retval;
 125             }
 126
 127           free (newp);
 128
 129 # ifndef __ASSUME_POSIX_TIMERS
 130           /* When we come here the syscall does not exist.  Make sure we
 131              do not try to use it again.  */
 132           __no_posix_timers = -1;
 133 # endif
 134         }
 135       else
 136         {
 137 # ifndef __ASSUME_POSIX_TIMERS
 138           /* Make sure we have the necessary kernel support.  */
 139           if (__no_posix_timers == 0)
 140             {
 141               INTERNAL_SYSCALL_DECL (err);
 142               struct timespec ts;
 143               int res;
 144               res = INTERNAL_SYSCALL (clock_getres, err, 2,
 145                                       CLOCK_REALTIME, &ts);
 146               __no_posix_timers = (INTERNAL_SYSCALL_ERROR_P (res, err)
 147                                    ? -1 : 1);
 148             }
 149
 150           if (__no_posix_timers > 0)
 151 # endif
 152             {
 153               /* Create the helper thread.  */
 154               pthread_once (&__helper_once, __start_helper_thread);
 155               if (__helper_tid == 0)
 156                 {
 157                   /* No resources to start the helper thread.  */
 158                   __set_errno (EAGAIN);
 159                   return -1;
 160                 }
 161
 162               struct timer *newp;
 163               newp = (struct timer *) malloc (sizeof (struct timer));
 164               if (newp == NULL)
 165                 return -1;
 166
 167               /* Copy the thread parameters the user provided.  */
 168               newp->sival = evp->sigev_value;
 169               newp->thrfunc = evp->sigev_notify_function;
 170
 171               /* We cannot simply copy the thread attributes since the
 172                  implementation might keep internal information for
 173                  each instance.  */
 174               (void) pthread_attr_init (&newp->attr);
 175               if (evp->sigev_notify_attributes != NULL)
 176                 {
 177                   struct pthread_attr *nattr;
 178                   struct pthread_attr *oattr;
 179
 180                   nattr = (struct pthread_attr *) &newp->attr;
 181                   oattr = (struct pthread_attr *) evp->sigev_notify_attributes;
 182
 183                   nattr->schedparam = oattr->schedparam;
 184                   nattr->schedpolicy = oattr->schedpolicy;
 185                   nattr->flags = oattr->flags;
 186                   nattr->guardsize = oattr->guardsize;
 187                   nattr->stackaddr = oattr->stackaddr;
 188                   nattr->stacksize = oattr->stacksize;
 189                 }
 190
 191               /* In any case set the detach flag.  */
 192               (void) pthread_attr_setdetachstate (&newp->attr,
 193                                                   PTHREAD_CREATE_DETACHED);
 194
 195               /* Create the event structure for the kernel timer.  */
 196               struct sigevent sev =
 197                 { .sigev_value.sival_ptr = newp,
 198                   .sigev_signo = SIGTIMER,
 199                   .sigev_notify = SIGEV_SIGNAL | SIGEV_THREAD_ID,
 200                   ._sigev_un = { ._pad = { [0] = __helper_tid } } };
 201
 202               /* Create the timer.  */
 203               INTERNAL_SYSCALL_DECL (err);
 204               int res;
 205               res = INTERNAL_SYSCALL (timer_create, err, 3,
 206                                       syscall_clockid, &sev, &newp->ktimerid);
 207               if (! INTERNAL_SYSCALL_ERROR_P (res, err))
 208                 {
 209                   /* Add to the queue of active timers with thread
 210                      delivery.  */
 211                   pthread_mutex_lock (&__active_timer_sigev_thread_lock);
 212                   newp->next = __active_timer_sigev_thread;
 213                   __active_timer_sigev_thread = newp;
 214                   pthread_mutex_unlock (&__active_timer_sigev_thread_lock);
 215
 216                   *timerid = (timer_t) newp;
 217                   return 0;
 218                 }
 219
 220               /* Free the resources.  */
 221               free (newp);
 222
 223               __set_errno (INTERNAL_SYSCALL_ERRNO (res, err));
 224
 225               return -1;
 226             }
 227         }
 228     }
 229
 230 # ifndef __ASSUME_POSIX_TIMERS
 231   /* Compatibility code.  */
 232   return compat_timer_create (clock_id, evp, timerid);
 233 # endif
 234 }
 235 #else
 236 # ifdef timer_create_alias
 237 #  define timer_create timer_create_alias
 238 # endif
 239 /* The new system calls are not available.  Use the userlevel
 240    implementation.  */
 241 # include <nptl/sysdeps/pthread/timer_create.c>
 242 #endif