linuxthreads/sysdeps/pthread/posix-timer.h

   1 /* Definitions for POSIX timer implementation on top of LinuxThreads.
   2    Copyright (C) 2000, 2002, 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 /* Static array with the structures for all the timers.  */
  73 extern struct timer_node __timer_array[TIMER_MAX];
  74
  75 /* Global lock to protect operation on the lists.  */
  76 extern pthread_mutex_t __timer_mutex;
  77
  78 /* Variable to protext initialization.  */
  79 extern pthread_once_t __timer_init_once_control;
  80
  81 /* Nonzero if initialization of timer implementation failed.  */
  82 extern int __timer_init_failed;
  83
  84 /* Nodes for the threads used to deliver signals.  */
  85 /* A distinct thread is used for each clock type.  */
  86
  87 extern struct thread_node __timer_signal_thread_rclk;
  88
  89
  90 /* Return pointer to timer structure corresponding to ID.  */
  91 static inline struct timer_node *
  92 timer_id2ptr (timer_t timerid)
  93 {
  94   if (timerid >= 0 && timerid < TIMER_MAX)
  95     return &__timer_array[timerid];
  96
  97   return NULL;
  98 }
  99
 100 /* Return ID of TIMER.  */
 101 static inline int
 102 timer_ptr2id (struct timer_node *timer)
 103 {
 104   return timer - __timer_array;
 105 }
 106
 107 /* Check whether timer is valid; global mutex must be held. */
 108 static inline int
 109 timer_valid (struct timer_node *timer)
 110 {
 111   return timer && timer->inuse == TIMER_INUSE;
 112 }
 113
 114 /* Timer refcount functions; need global mutex. */
 115 extern void __timer_dealloc (struct timer_node *timer);
 116
 117 static inline void
 118 timer_addref (struct timer_node *timer)
 119 {
 120   timer->refcount++;
 121 }
 122
 123 static inline void
 124 timer_delref (struct timer_node *timer)
 125 {
 126   if (--timer->refcount == 0)
 127     __timer_dealloc (timer);
 128 }
 129
 130 /* Timespec helper routines.  */
 131 static inline int
 132 timespec_compare (const struct timespec *left, const struct timespec *right)
 133 {
 134   if (left->tv_sec < right->tv_sec)
 135     return -1;
 136   if (left->tv_sec > right->tv_sec)
 137     return 1;
 138
 139   if (left->tv_nsec < right->tv_nsec)
 140     return -1;
 141   if (left->tv_nsec > right->tv_nsec)
 142     return 1;
 143
 144   return 0;
 145 }
 146
 147 static inline void
 148 timespec_add (struct timespec *sum, const struct timespec *left,
 149               const struct timespec *right)
 150 {
 151   sum->tv_sec = left->tv_sec + right->tv_sec;
 152   sum->tv_nsec = left->tv_nsec + right->tv_nsec;
 153
 154   if (sum->tv_nsec >= 1000000000)
 155     {
 156       ++sum->tv_sec;
 157       sum->tv_nsec -= 1000000000;
 158     }
 159 }
 160
 161 static inline void
 162 timespec_sub (struct timespec *diff, const struct timespec *left,
 163               const struct timespec *right)
 164 {
 165   diff->tv_sec = left->tv_sec - right->tv_sec;
 166   diff->tv_nsec = left->tv_nsec - right->tv_nsec;
 167
 168   if (diff->tv_nsec < 0)
 169     {
 170       --diff->tv_sec;
 171       diff->tv_nsec += 1000000000;
 172     }
 173 }
 174
 175
 176 /* We need one of the list functions in the other modules.  */
 177 static inline void
 178 list_unlink_ip (struct list_links *list)
 179 {
 180   struct list_links *lnext = list->next, *lprev = list->prev;
 181
 182   lnext->prev = lprev;
 183   lprev->next = lnext;
 184
 185   /* The suffix ip means idempotent; list_unlink_ip can be called
 186    * two or more times on the same node.
 187    */
 188
 189   list->next = list;
 190   list->prev = list;
 191 }
 192
 193
 194 /* Functions in the helper file.  */
 195 extern void __timer_mutex_cancel_handler (void *arg);
 196 extern void __timer_init_once (void);
 197 extern struct timer_node *__timer_alloc (void);
 198 extern int __timer_thread_start (struct thread_node *thread);
 199 extern struct thread_node *__timer_thread_find_matching (const pthread_attr_t *desired_attr, clockid_t);
 200 extern struct thread_node *__timer_thread_alloc (const pthread_attr_t *desired_attr, clockid_t);
 201 extern void __timer_thread_dealloc (struct thread_node *thread);
 202 extern int __timer_thread_queue_timer (struct thread_node *thread,
 203                                        struct timer_node *insert);
 204 extern void __timer_thread_wakeup (struct thread_node *thread);