nptl/sysdeps/pthread/posix-timer.h

   1 /* Definitions for POSIX timer implementation on top of NPTL.
   2    Copyright (C) 2000, 2002, 2003, 2004 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Kaz Kylheku <kaz@ashi.footprints.net>.
   5
   6    The GNU C Library is free software; you can redistribute it and/or
   7    modify it under the terms of the GNU Lesser General Public License as
   8    published by the Free Software Foundation; either version 2.1 of the
   9    License, or (at your option) any later version.
  10
  11    The GNU C Library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14    Lesser General Public License for more details.
  15
  16    You should have received a copy of the GNU Lesser General Public
  17    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  18    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  19    Boston, MA 02111-1307, USA.  */
  20
  21 #include <limits.h>
  22 #include <signal.h>
  23
  24 /* Double linked list.  */
  25 struct list_links
  26 {
  27   struct list_links *next;
  28   struct list_links *prev;
  29 };
  30
  31
  32 /* Forward declaration.  */
  33 struct timer_node;
  34
  35
  36 /* Definitions for an internal thread of the POSIX timer implementation.  */
  37 struct thread_node
  38 {
  39   struct list_links links;
  40   pthread_attr_t attr;
  41   pthread_t id;
  42   unsigned int exists;
  43   struct list_links timer_queue;
  44   pthread_cond_t cond;
  45   struct timer_node *current_timer;
  46   pthread_t captured;
  47   clockid_t clock_id;
  48 };
  49
  50
  51 /* Internal representation of a timer.  */
  52 struct timer_node
  53 {
  54   struct list_links links;
  55   struct sigevent event;
  56   clockid_t clock;
  57   struct itimerspec value;
  58   struct timespec expirytime;
  59   pthread_attr_t attr;
  60   unsigned int abstime;
  61   unsigned int armed;
  62   enum {
  63     TIMER_FREE, TIMER_INUSE, TIMER_DELETED
  64   } inuse;
  65   struct thread_node *thread;
  66   pid_t creator_pid;
  67   int refcount;
  68   int overrun_count;
  69 };
  70
  71
  72 /* The limit is not published if we are compiled with kernel timer support.
  73    But we still compiled in this implementation with its limit unless built
  74    to require the kernel support.  */
  75 #ifndef TIMER_MAX
  76 # define TIMER_MAX 256
  77 #endif
  78
  79 /* Static array with the structures for all the timers.  */
  80 extern struct timer_node __timer_array[TIMER_MAX];
  81
  82 /* Global lock to protect operation on the lists.  */
  83 extern pthread_mutex_t __timer_mutex;
  84
  85 /* Variable to protext initialization.  */
  86 extern pthread_once_t __timer_init_once_control;
  87
  88 /* Nonzero if initialization of timer implementation failed.  */
  89 extern int __timer_init_failed;
  90
  91 /* Node for the thread used to deliver signals.  */
  92 extern struct thread_node __timer_signal_thread_rclk;
  93
  94
  95 /* Return pointer to timer structure corresponding to ID.  */
  96 #define timer_id2ptr(timerid) ((struct timer_node *) timerid)
  97 #define timer_ptr2id(timerid) ((void *) timerid)
  98
  99 /* Check whether timer is valid; global mutex must be held. */
 100 static inline int
 101 timer_valid (struct timer_node *timer)
 102 {
 103   return timer && timer->inuse == TIMER_INUSE;
 104 }
 105
 106 /* Timer refcount functions; need global mutex. */
 107 extern void __timer_dealloc (struct timer_node *timer);
 108
 109 static inline void
 110 timer_addref (struct timer_node *timer)
 111 {
 112   timer->refcount++;
 113 }
 114
 115 static inline void
 116 timer_delref (struct timer_node *timer)
 117 {
 118   if (--timer->refcount == 0)
 119     __timer_dealloc (timer);
 120 }
 121
 122 /* Timespec helper routines.  */
 123 static inline int
 124 __attribute ((always_inline))
 125 timespec_compare (const struct timespec *left, const struct timespec *right)
 126 {
 127   if (left->tv_sec < right->tv_sec)
 128     return -1;
 129   if (left->tv_sec > right->tv_sec)
 130     return 1;
 131
 132   if (left->tv_nsec < right->tv_nsec)
 133     return -1;
 134   if (left->tv_nsec > right->tv_nsec)
 135     return 1;
 136
 137   return 0;
 138 }
 139
 140 static inline void
 141 timespec_add (struct timespec *sum, const struct timespec *left,
 142               const struct timespec *right)
 143 {
 144   sum->tv_sec = left->tv_sec + right->tv_sec;
 145   sum->tv_nsec = left->tv_nsec + right->tv_nsec;
 146
 147   if (sum->tv_nsec >= 1000000000)
 148     {
 149       ++sum->tv_sec;
 150       sum->tv_nsec -= 1000000000;
 151     }
 152 }
 153
 154 static inline void
 155 timespec_sub (struct timespec *diff, const struct timespec *left,
 156               const struct timespec *right)
 157 {
 158   diff->tv_sec = left->tv_sec - right->tv_sec;
 159   diff->tv_nsec = left->tv_nsec - right->tv_nsec;
 160
 161   if (diff->tv_nsec < 0)
 162     {
 163       --diff->tv_sec;
 164       diff->tv_nsec += 1000000000;
 165     }
 166 }
 167
 168
 169 /* We need one of the list functions in the other modules.  */
 170 static inline void
 171 list_unlink_ip (struct list_links *list)
 172 {
 173   struct list_links *lnext = list->next, *lprev = list->prev;
 174
 175   lnext->prev = lprev;
 176   lprev->next = lnext;
 177
 178   /* The suffix ip means idempotent; list_unlink_ip can be called
 179    * two or more times on the same node.
 180    */
 181
 182   list->next = list;
 183   list->prev = list;
 184 }
 185
 186
 187 /* Functions in the helper file.  */
 188 extern void __timer_mutex_cancel_handler (void *arg);
 189 extern void __timer_init_once (void);
 190 extern struct timer_node *__timer_alloc (void);
 191 extern int __timer_thread_start (struct thread_node *thread);
 192 extern struct thread_node *__timer_thread_find_matching (const pthread_attr_t *desired_attr, clockid_t);
 193 extern struct thread_node *__timer_thread_alloc (const pthread_attr_t *desired_attr, clockid_t);
 194 extern void __timer_thread_dealloc (struct thread_node *thread);
 195 extern int __timer_thread_queue_timer (struct thread_node *thread,
 196                                        struct timer_node *insert);
 197 extern void __timer_thread_wakeup (struct thread_node *thread);