/* Definitions for POSIX timer implementation on top of LinuxThreads.   Copyright (C) 2000 Free Software Foundation, Inc.   This file is part of the GNU C Library.   Contributed by Kaz Kylheku <kaz@ashi.footprints.net>.   The GNU C Library is free software; you can redistribute it and/or   modify it under the terms of the GNU Library General Public License as   published by the Free Software Foundation; either version 2 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   Library General Public License for more details.   You should have received a copy of the GNU Library General Public   License along with the GNU C Library; see the file COPYING.LIB.  If not,   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,   Boston, MA 02111-1307, USA.  */#include <limits.h>#include <signal.h>#include <linux/time.h>/* Double linked list.  */struct list_links{  struct list_links *next;  struct list_links *prev;};/* Forward declaration.  */struct timer_node;/* Definitions for an internal thread of the POSIX timer implementation.  */struct thread_node{  struct list_links links;  pthread_attr_t attr;  pthread_t id;  unsigned int exists;  struct list_links timer_queue;  pthread_cond_t cond;  struct timer_node *current_timer;  pthread_t captured;  clockid_t clock_id;};/* Internal representation of a timer.  */struct timer_node{  struct list_links links;  struct sigevent event;  clockid_t clock;  struct itimerspec value;  struct timespec expirytime;  pthread_attr_t attr;  unsigned int abstime;  unsigned int armed;  enum {    TIMER_FREE, TIMER_INUSE, TIMER_DELETED  } inuse;  struct thread_node *thread;  pid_t creator_pid;  int refcount;};/* Static array with the structures for all the timers.  */extern struct timer_node __timer_array[TIMER_MAX];/* Global lock to protect operation on the lists.  */extern pthread_mutex_t __timer_mutex;/* Variable to protext initialization.  */extern pthread_once_t __timer_init_once_control;/* Nonzero if initialization of timer implementation failed.  */extern int __timer_init_failed;/* Nodes for the threads used to deliver signals.  *//* A distinct thread is used for each clock type.  */extern struct thread_node __timer_signal_thread_rclk;#ifdef _POSIX_CPUTIMEextern struct thread_node __timer_signal_thread_pclk;#endif#ifdef _POSIX_THREAD_CPUTIMEextern struct thread_node __timer_signal_thread_tclk;#endif/* Return pointer to timer structure corresponding to ID.  */static inline struct timer_node *timer_id2ptr (timer_t timerid){  if (timerid >= 0 && timerid < TIMER_MAX)    return &__timer_array[timerid];  return NULL;}/* Return ID of TIMER.  */static inline inttimer_ptr2id (struct timer_node *timer){  return timer - __timer_array;}/* Check whether timer is valid; global mutex must be held. */static inline inttimer_valid (struct timer_node *timer){  return timer && timer->inuse == TIMER_INUSE;}/* Timer refcount functions; need global mutex. */extern void __timer_dealloc (struct timer_node *timer);static inline voidtimer_addref (struct timer_node *timer){  timer->refcount++;}static inline voidtimer_delref (struct timer_node *timer){  if (--timer->refcount == 0)    __timer_dealloc (timer);}/* Timespec helper routines.  */static inline inttimespec_compare (const struct timespec *left, const struct timespec *right){  if (left->tv_sec < right->tv_sec)    return -1;  if (left->tv_sec > right->tv_sec)    return 1;  if (left->tv_nsec < right->tv_nsec)    return -1;  if (left->tv_nsec > right->tv_nsec)    return 1;  return 0;}static inline voidtimespec_add (struct timespec *sum, const struct timespec *left,	      const struct timespec *right){  sum->tv_sec = left->tv_sec + right->tv_sec;  sum->tv_nsec = left->tv_nsec + right->tv_nsec;  if (sum->tv_nsec >= 1000000000)    {      ++sum->tv_sec;      sum->tv_nsec -= 1000000000;    }}static inline voidtimespec_sub (struct timespec *diff, const struct timespec *left,	      const struct timespec *right){  diff->tv_sec = left->tv_sec - right->tv_sec;  diff->tv_nsec = left->tv_nsec - right->tv_nsec;  if (diff->tv_nsec < 0)    {      --diff->tv_sec;      diff->tv_nsec += 1000000000;    }}/* We need one of the list functions in the other modules.  */static inline voidlist_unlink_ip (struct list_links *list){  struct list_links *lnext = list->next, *lprev = list->prev;  lnext->prev = lprev;  lprev->next = lnext;  /* The suffix ip means idempotent; list_unlink_ip can be called   * two or more times on the same node.   */  list->next = list;  list->prev = list;}/* Functions in the helper file.  */extern void __timer_mutex_cancel_handler (void *arg);extern void __timer_init_once (void);extern struct timer_node *__timer_alloc (void);extern int __timer_thread_start (struct thread_node *thread);extern struct thread_node *__timer_thread_find_matching (const pthread_attr_t *desired_attr, clockid_t);extern struct thread_node *__timer_thread_alloc (const pthread_attr_t *desired_attr, clockid_t);extern void __timer_thread_dealloc (struct thread_node *thread);extern int __timer_thread_queue_timer (struct thread_node *thread,				       struct timer_node *insert);extern void __timer_thread_wakeup (struct thread_node *thread);