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2.5-18.1
This commit is contained in:
Jakub Jelinek
@@ -1,573 +0,0 @@
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/* Helper code for POSIX timer implementation on LinuxThreads.
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Copyright (C) 2000, 2001, 2002, 2004 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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Contributed by Kaz Kylheku <kaz@ashi.footprints.net>.
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The GNU C Library is free software; you can redistribute it and/or
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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.
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||||
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The GNU C Library is distributed in the hope that it will be useful,
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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.
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||||
|
||||
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,
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write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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Boston, MA 02111-1307, USA. */
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#include <assert.h>
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#include <errno.h>
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#include <pthread.h>
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#include <stddef.h>
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#include <stdlib.h>
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#include <string.h>
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#include <sysdep.h>
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#include <time.h>
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#include <unistd.h>
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#include <sys/syscall.h>
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#include "posix-timer.h"
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/* Number of threads used. */
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#define THREAD_MAXNODES 16
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/* Array containing the descriptors for the used threads. */
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static struct thread_node thread_array[THREAD_MAXNODES];
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/* Static array with the structures for all the timers. */
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struct timer_node __timer_array[TIMER_MAX];
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/* Global lock to protect operation on the lists. */
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pthread_mutex_t __timer_mutex = PTHREAD_MUTEX_INITIALIZER;
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/* Variable to protext initialization. */
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pthread_once_t __timer_init_once_control = PTHREAD_ONCE_INIT;
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/* Nonzero if initialization of timer implementation failed. */
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int __timer_init_failed;
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/* Node for the thread used to deliver signals. */
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struct thread_node __timer_signal_thread_rclk;
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/* Lists to keep free and used timers and threads. */
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struct list_links timer_free_list;
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struct list_links thread_free_list;
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struct list_links thread_active_list;
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#ifdef __NR_rt_sigqueueinfo
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extern int __syscall_rt_sigqueueinfo (int, int, siginfo_t *);
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#endif
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/* List handling functions. */
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static inline void
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list_init (struct list_links *list)
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{
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list->next = list->prev = list;
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}
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static inline void
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list_append (struct list_links *list, struct list_links *newp)
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{
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newp->prev = list->prev;
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newp->next = list;
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list->prev->next = newp;
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list->prev = newp;
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}
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static inline void
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list_insbefore (struct list_links *list, struct list_links *newp)
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{
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list_append (list, newp);
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}
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/*
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* Like list_unlink_ip, except that calling it on a node that
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* is already unlinked is disastrous rather than a noop.
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*/
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static inline void
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list_unlink (struct list_links *list)
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{
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struct list_links *lnext = list->next, *lprev = list->prev;
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lnext->prev = lprev;
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lprev->next = lnext;
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}
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static inline struct list_links *
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list_first (struct list_links *list)
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{
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return list->next;
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}
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static inline struct list_links *
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list_null (struct list_links *list)
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{
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return list;
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}
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static inline struct list_links *
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list_next (struct list_links *list)
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{
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return list->next;
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}
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static inline int
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list_isempty (struct list_links *list)
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{
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return list->next == list;
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}
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/* Functions build on top of the list functions. */
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static inline struct thread_node *
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thread_links2ptr (struct list_links *list)
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{
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return (struct thread_node *) ((char *) list
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- offsetof (struct thread_node, links));
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}
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static inline struct timer_node *
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timer_links2ptr (struct list_links *list)
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{
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return (struct timer_node *) ((char *) list
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- offsetof (struct timer_node, links));
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}
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/* Initialize a newly allocated thread structure. */
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static void
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thread_init (struct thread_node *thread, const pthread_attr_t *attr, clockid_t clock_id)
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{
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if (attr != NULL)
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thread->attr = *attr;
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else
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{
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pthread_attr_init (&thread->attr);
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pthread_attr_setdetachstate (&thread->attr, PTHREAD_CREATE_DETACHED);
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}
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thread->exists = 0;
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list_init (&thread->timer_queue);
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pthread_cond_init (&thread->cond, 0);
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thread->current_timer = 0;
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thread->captured = pthread_self ();
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thread->clock_id = clock_id;
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}
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/* Initialize the global lists, and acquire global resources. Error
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reporting is done by storing a non-zero value to the global variable
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timer_init_failed. */
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static void
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init_module (void)
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{
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int i;
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list_init (&timer_free_list);
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list_init (&thread_free_list);
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list_init (&thread_active_list);
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for (i = 0; i < TIMER_MAX; ++i)
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{
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list_append (&timer_free_list, &__timer_array[i].links);
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__timer_array[i].inuse = TIMER_FREE;
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}
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for (i = 0; i < THREAD_MAXNODES; ++i)
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list_append (&thread_free_list, &thread_array[i].links);
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thread_init (&__timer_signal_thread_rclk, 0, CLOCK_REALTIME);
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}
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/* This is a handler executed in a child process after a fork()
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occurs. It reinitializes the module, resetting all of the data
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structures to their initial state. The mutex is initialized in
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case it was locked in the parent process. */
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static void
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reinit_after_fork (void)
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{
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init_module ();
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pthread_mutex_init (&__timer_mutex, 0);
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}
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/* Called once form pthread_once in timer_init. This initializes the
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module and ensures that reinit_after_fork will be executed in any
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child process. */
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void
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__timer_init_once (void)
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{
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init_module ();
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pthread_atfork (0, 0, reinit_after_fork);
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}
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/* Deinitialize a thread that is about to be deallocated. */
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static void
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thread_deinit (struct thread_node *thread)
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{
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assert (list_isempty (&thread->timer_queue));
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pthread_cond_destroy (&thread->cond);
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}
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/* Allocate a thread structure from the global free list. Global
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mutex lock must be held by caller. The thread is moved to
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the active list. */
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struct thread_node *
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__timer_thread_alloc (const pthread_attr_t *desired_attr, clockid_t clock_id)
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{
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struct list_links *node = list_first (&thread_free_list);
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if (node != list_null (&thread_free_list))
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{
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struct thread_node *thread = thread_links2ptr (node);
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list_unlink (node);
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thread_init (thread, desired_attr, clock_id);
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list_append (&thread_active_list, node);
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return thread;
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}
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return 0;
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}
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/* Return a thread structure to the global free list. Global lock
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must be held by caller. */
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void
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__timer_thread_dealloc (struct thread_node *thread)
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{
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thread_deinit (thread);
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list_unlink (&thread->links);
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list_append (&thread_free_list, &thread->links);
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}
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/* Each of our threads which terminates executes this cleanup
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handler. We never terminate threads ourselves; if a thread gets here
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it means that the evil application has killed it. If the thread has
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timers, these require servicing and so we must hire a replacement
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thread right away. We must also unblock another thread that may
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have been waiting for this thread to finish servicing a timer (see
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timer_delete()). */
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static void
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thread_cleanup (void *val)
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{
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if (val != NULL)
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{
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struct thread_node *thread = val;
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/* How did the signal thread get killed? */
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assert (thread != &__timer_signal_thread_rclk);
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pthread_mutex_lock (&__timer_mutex);
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thread->exists = 0;
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/* We are no longer processing a timer event. */
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thread->current_timer = 0;
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if (list_isempty (&thread->timer_queue))
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__timer_thread_dealloc (thread);
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else
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(void) __timer_thread_start (thread);
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pthread_mutex_unlock (&__timer_mutex);
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/* Unblock potentially blocked timer_delete(). */
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pthread_cond_broadcast (&thread->cond);
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}
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}
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/* Handle a timer which is supposed to go off now. */
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static void
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thread_expire_timer (struct thread_node *self, struct timer_node *timer)
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{
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self->current_timer = timer; /* Lets timer_delete know timer is running. */
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pthread_mutex_unlock (&__timer_mutex);
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switch (__builtin_expect (timer->event.sigev_notify, SIGEV_SIGNAL))
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{
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case SIGEV_NONE:
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break;
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case SIGEV_SIGNAL:
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#ifdef __NR_rt_sigqueueinfo
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{
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siginfo_t info;
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/* First, clear the siginfo_t structure, so that we don't pass our
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stack content to other tasks. */
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memset (&info, 0, sizeof (siginfo_t));
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/* We must pass the information about the data in a siginfo_t
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value. */
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info.si_signo = timer->event.sigev_signo;
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info.si_code = SI_TIMER;
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info.si_pid = timer->creator_pid;
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info.si_uid = getuid ();
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info.si_value = timer->event.sigev_value;
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INLINE_SYSCALL (rt_sigqueueinfo, 3, info.si_pid, info.si_signo, &info);
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}
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#else
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if (pthread_kill (self->captured, timer->event.sigev_signo) != 0)
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{
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if (pthread_kill (self->id, timer->event.sigev_signo) != 0)
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abort ();
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}
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#endif
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break;
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case SIGEV_THREAD:
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timer->event.sigev_notify_function (timer->event.sigev_value);
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break;
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default:
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assert (! "unknown event");
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break;
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}
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pthread_mutex_lock (&__timer_mutex);
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self->current_timer = 0;
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pthread_cond_broadcast (&self->cond);
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}
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/* Thread function; executed by each timer thread. The job of this
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function is to wait on the thread's timer queue and expire the
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timers in chronological order as close to their scheduled time as
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possible. */
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static void
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__attribute__ ((noreturn))
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thread_func (void *arg)
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{
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struct thread_node *self = arg;
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/* Register cleanup handler, in case rogue application terminates
|
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this thread. (This cannot happen to __timer_signal_thread, which
|
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doesn't invoke application callbacks). */
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pthread_cleanup_push (thread_cleanup, self);
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pthread_mutex_lock (&__timer_mutex);
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|
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while (1)
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{
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struct list_links *first;
|
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struct timer_node *timer = NULL;
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|
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/* While the timer queue is not empty, inspect the first node. */
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first = list_first (&self->timer_queue);
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if (first != list_null (&self->timer_queue))
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{
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struct timespec now;
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||||
|
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timer = timer_links2ptr (first);
|
||||
|
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/* This assumes that the elements of the list of one thread
|
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are all for the same clock. */
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clock_gettime (timer->clock, &now);
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||||
|
||||
while (1)
|
||||
{
|
||||
/* If the timer is due or overdue, remove it from the queue.
|
||||
If it's a periodic timer, re-compute its new time and
|
||||
requeue it. Either way, perform the timer expiry. */
|
||||
if (timespec_compare (&now, &timer->expirytime) < 0)
|
||||
break;
|
||||
|
||||
list_unlink_ip (first);
|
||||
|
||||
if (__builtin_expect (timer->value.it_interval.tv_sec, 0) != 0
|
||||
|| timer->value.it_interval.tv_nsec != 0)
|
||||
{
|
||||
timer->overrun_count = 0;
|
||||
timespec_add (&timer->expirytime, &timer->expirytime,
|
||||
&timer->value.it_interval);
|
||||
while (timespec_compare (&timer->expirytime, &now) < 0)
|
||||
{
|
||||
timespec_add (&timer->expirytime, &timer->expirytime,
|
||||
&timer->value.it_interval);
|
||||
if (timer->overrun_count < DELAYTIMER_MAX)
|
||||
++timer->overrun_count;
|
||||
}
|
||||
__timer_thread_queue_timer (self, timer);
|
||||
}
|
||||
|
||||
thread_expire_timer (self, timer);
|
||||
|
||||
first = list_first (&self->timer_queue);
|
||||
if (first == list_null (&self->timer_queue))
|
||||
break;
|
||||
|
||||
timer = timer_links2ptr (first);
|
||||
}
|
||||
}
|
||||
|
||||
/* If the queue is not empty, wait until the expiry time of the
|
||||
first node. Otherwise wait indefinitely. Insertions at the
|
||||
head of the queue must wake up the thread by broadcasting
|
||||
this condition variable. */
|
||||
if (timer != NULL)
|
||||
pthread_cond_timedwait (&self->cond, &__timer_mutex,
|
||||
&timer->expirytime);
|
||||
else
|
||||
pthread_cond_wait (&self->cond, &__timer_mutex);
|
||||
}
|
||||
/* This macro will never be executed since the while loop loops
|
||||
forever - but we have to add it for proper nesting. */
|
||||
pthread_cleanup_pop (1);
|
||||
}
|
||||
|
||||
|
||||
/* Enqueue a timer in wakeup order in the thread's timer queue.
|
||||
Returns 1 if the timer was inserted at the head of the queue,
|
||||
causing the queue's next wakeup time to change. */
|
||||
|
||||
int
|
||||
__timer_thread_queue_timer (struct thread_node *thread,
|
||||
struct timer_node *insert)
|
||||
{
|
||||
struct list_links *iter;
|
||||
int athead = 1;
|
||||
|
||||
for (iter = list_first (&thread->timer_queue);
|
||||
iter != list_null (&thread->timer_queue);
|
||||
iter = list_next (iter))
|
||||
{
|
||||
struct timer_node *timer = timer_links2ptr (iter);
|
||||
|
||||
if (timespec_compare (&insert->expirytime, &timer->expirytime) < 0)
|
||||
break;
|
||||
athead = 0;
|
||||
}
|
||||
|
||||
list_insbefore (iter, &insert->links);
|
||||
return athead;
|
||||
}
|
||||
|
||||
|
||||
/* Start a thread and associate it with the given thread node. Global
|
||||
lock must be held by caller. */
|
||||
int
|
||||
__timer_thread_start (struct thread_node *thread)
|
||||
{
|
||||
int retval = 1;
|
||||
|
||||
assert (!thread->exists);
|
||||
thread->exists = 1;
|
||||
|
||||
if (pthread_create (&thread->id, &thread->attr,
|
||||
(void *(*) (void *)) thread_func, thread) != 0)
|
||||
{
|
||||
thread->exists = 0;
|
||||
retval = -1;
|
||||
}
|
||||
|
||||
return retval;
|
||||
}
|
||||
|
||||
|
||||
void
|
||||
__timer_thread_wakeup (struct thread_node *thread)
|
||||
{
|
||||
pthread_cond_broadcast (&thread->cond);
|
||||
}
|
||||
|
||||
|
||||
/* Compare two pthread_attr_t thread attributes for exact equality.
|
||||
Returns 1 if they are equal, otherwise zero if they are not equal or
|
||||
contain illegal values. This version is LinuxThreads-specific for
|
||||
performance reason. One could use the access functions to get the
|
||||
values of all the fields of the attribute structure. */
|
||||
static int
|
||||
thread_attr_compare (const pthread_attr_t *left, const pthread_attr_t *right)
|
||||
{
|
||||
return (left->__detachstate == right->__detachstate
|
||||
&& left->__schedpolicy == right->__schedpolicy
|
||||
&& left->__guardsize == right->__guardsize
|
||||
&& (left->__schedparam.sched_priority
|
||||
== right->__schedparam.sched_priority)
|
||||
&& left->__inheritsched == right->__inheritsched
|
||||
&& left->__scope == right->__scope
|
||||
&& left->__stacksize == right->__stacksize
|
||||
&& left->__stackaddr_set == right->__stackaddr_set
|
||||
&& (left->__stackaddr_set
|
||||
|| left->__stackaddr == right->__stackaddr));
|
||||
}
|
||||
|
||||
|
||||
/* Search the list of active threads and find one which has matching
|
||||
attributes. Global mutex lock must be held by caller. */
|
||||
struct thread_node *
|
||||
__timer_thread_find_matching (const pthread_attr_t *desired_attr,
|
||||
clockid_t desired_clock_id)
|
||||
{
|
||||
struct list_links *iter = list_first (&thread_active_list);
|
||||
|
||||
while (iter != list_null (&thread_active_list))
|
||||
{
|
||||
struct thread_node *candidate = thread_links2ptr (iter);
|
||||
|
||||
if (thread_attr_compare (desired_attr, &candidate->attr)
|
||||
&& desired_clock_id == candidate->clock_id)
|
||||
return candidate;
|
||||
|
||||
iter = list_next (iter);
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
|
||||
/* Grab a free timer structure from the global free list. The global
|
||||
lock must be held by the caller. */
|
||||
struct timer_node *
|
||||
__timer_alloc (void)
|
||||
{
|
||||
struct list_links *node = list_first (&timer_free_list);
|
||||
|
||||
if (node != list_null (&timer_free_list))
|
||||
{
|
||||
struct timer_node *timer = timer_links2ptr (node);
|
||||
list_unlink_ip (node);
|
||||
timer->inuse = TIMER_INUSE;
|
||||
timer->refcount = 1;
|
||||
return timer;
|
||||
}
|
||||
|
||||
return NULL;
|
||||
}
|
||||
|
||||
|
||||
/* Return a timer structure to the global free list. The global lock
|
||||
must be held by the caller. */
|
||||
void
|
||||
__timer_dealloc (struct timer_node *timer)
|
||||
{
|
||||
assert (timer->refcount == 0);
|
||||
timer->thread = NULL; /* Break association between timer and thread. */
|
||||
timer->inuse = TIMER_FREE;
|
||||
list_append (&timer_free_list, &timer->links);
|
||||
}
|
||||
|
||||
|
||||
/* Thread cancellation handler which unlocks a mutex. */
|
||||
void
|
||||
__timer_mutex_cancel_handler (void *arg)
|
||||
{
|
||||
pthread_mutex_unlock (arg);
|
||||
}
|
||||
Reference in New Issue
Block a user