b5a8a15c2f
file descriptors needing to be polled (Doh!). Reported
by Dan Nelson <dnelson@emsphone.com>.
Don't install and start the scheduling timer until the
first thread is created. This prevents the overhead of
having a periodic scheduling signal in a single threaded
program. Reported by Dan Nelson <dnelson@emsphone.com>.
Allow builtin longjmps out of application installed
signal handlers without the need perform any post-handler
cleanup:
o Change signal handling to save the threads interrupted
context on the stack. The threads current context is
now always stored in the same place (in the pthread).
If and when a signal handler returns, the interrupted
context is copied back to the storage area in the pthread.
o Before calling invoking a signal handler for a thread,
back the thread out of any internal waiting queues
(mutex, CV, join, etc) to which it belongs.
Rework uthread_info.c a bit to make it easier to change
the format of a thread dump.
Use an alternal signal stack for the thread library's
signal handler. This allows us to fiddle with the main
threads stack without fear of it being in use.
Reviewed by: jasone
756 lines
19 KiB
C
756 lines
19 KiB
C
/*
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* Copyright (c) 1995 John Birrell <jb@cimlogic.com.au>.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. All advertising materials mentioning features or use of this software
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* must display the following acknowledgement:
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* This product includes software developed by John Birrell.
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* 4. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY JOHN BIRRELL AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#include <stdlib.h>
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#include <errno.h>
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#include <string.h>
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#ifdef _THREAD_SAFE
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#include <pthread.h>
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#include "pthread_private.h"
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/*
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* Prototypes
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*/
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static inline pthread_t cond_queue_deq(pthread_cond_t);
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static inline void cond_queue_remove(pthread_cond_t, pthread_t);
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static inline void cond_queue_enq(pthread_cond_t, pthread_t);
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/* Reinitialize a condition variable to defaults. */
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int
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_cond_reinit(pthread_cond_t *cond)
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{
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int ret = 0;
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if (cond == NULL)
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ret = EINVAL;
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else if (*cond == NULL)
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ret = pthread_cond_init(cond, NULL);
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else {
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/*
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* Initialize the condition variable structure:
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*/
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TAILQ_INIT(&(*cond)->c_queue);
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(*cond)->c_flags = COND_FLAGS_INITED;
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(*cond)->c_type = COND_TYPE_FAST;
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(*cond)->c_mutex = NULL;
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(*cond)->c_seqno = 0;
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memset(&(*cond)->lock, 0, sizeof((*cond)->lock));
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}
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return (ret);
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}
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int
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pthread_cond_init(pthread_cond_t *cond, const pthread_condattr_t *cond_attr)
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{
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enum pthread_cond_type type;
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pthread_cond_t pcond;
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int rval = 0;
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if (cond == NULL)
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rval = EINVAL;
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else {
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/*
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* Check if a pointer to a condition variable attribute
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* structure was passed by the caller:
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*/
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if (cond_attr != NULL && *cond_attr != NULL) {
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/* Default to a fast condition variable: */
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type = (*cond_attr)->c_type;
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} else {
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/* Default to a fast condition variable: */
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type = COND_TYPE_FAST;
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}
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/* Process according to condition variable type: */
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switch (type) {
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/* Fast condition variable: */
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case COND_TYPE_FAST:
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/* Nothing to do here. */
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break;
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/* Trap invalid condition variable types: */
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default:
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/* Return an invalid argument error: */
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rval = EINVAL;
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break;
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}
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/* Check for no errors: */
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if (rval == 0) {
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if ((pcond = (pthread_cond_t)
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malloc(sizeof(struct pthread_cond))) == NULL) {
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rval = ENOMEM;
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} else {
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/*
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* Initialise the condition variable
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* structure:
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*/
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TAILQ_INIT(&pcond->c_queue);
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pcond->c_flags |= COND_FLAGS_INITED;
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pcond->c_type = type;
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pcond->c_mutex = NULL;
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pcond->c_seqno = 0;
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memset(&pcond->lock,0,sizeof(pcond->lock));
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*cond = pcond;
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}
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}
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}
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/* Return the completion status: */
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return (rval);
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}
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int
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pthread_cond_destroy(pthread_cond_t *cond)
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{
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int rval = 0;
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if (cond == NULL || *cond == NULL)
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rval = EINVAL;
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else {
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/* Lock the condition variable structure: */
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_SPINLOCK(&(*cond)->lock);
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/*
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* Free the memory allocated for the condition
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* variable structure:
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*/
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free(*cond);
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/*
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* NULL the caller's pointer now that the condition
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* variable has been destroyed:
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*/
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*cond = NULL;
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}
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/* Return the completion status: */
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return (rval);
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}
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int
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pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex)
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{
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int rval = 0;
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int done = 0;
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int interrupted = 0;
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int unlock_mutex = 1;
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int seqno;
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_thread_enter_cancellation_point();
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if (cond == NULL)
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return (EINVAL);
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/*
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* If the condition variable is statically initialized,
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* perform the dynamic initialization:
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*/
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if (*cond == NULL &&
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(rval = pthread_cond_init(cond, NULL)) != 0)
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return (rval);
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/*
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* Enter a loop waiting for a condition signal or broadcast
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* to wake up this thread. A loop is needed in case the waiting
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* thread is interrupted by a signal to execute a signal handler.
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* It is not (currently) possible to remain in the waiting queue
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* while running a handler. Instead, the thread is interrupted
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* and backed out of the waiting queue prior to executing the
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* signal handler.
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*/
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do {
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/* Lock the condition variable structure: */
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_SPINLOCK(&(*cond)->lock);
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/*
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* If the condvar was statically allocated, properly
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* initialize the tail queue.
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*/
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if (((*cond)->c_flags & COND_FLAGS_INITED) == 0) {
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TAILQ_INIT(&(*cond)->c_queue);
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(*cond)->c_flags |= COND_FLAGS_INITED;
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}
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/* Process according to condition variable type: */
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switch ((*cond)->c_type) {
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/* Fast condition variable: */
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case COND_TYPE_FAST:
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if ((mutex == NULL) || (((*cond)->c_mutex != NULL) &&
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((*cond)->c_mutex != *mutex))) {
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/* Unlock the condition variable structure: */
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_SPINUNLOCK(&(*cond)->lock);
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/* Return invalid argument error: */
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rval = EINVAL;
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} else {
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/* Reset the timeout and interrupted flags: */
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_thread_run->timeout = 0;
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_thread_run->interrupted = 0;
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/*
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* Queue the running thread for the condition
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* variable:
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*/
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cond_queue_enq(*cond, _thread_run);
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/* Remember the mutex and sequence number: */
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(*cond)->c_mutex = *mutex;
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seqno = (*cond)->c_seqno;
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/* Wait forever: */
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_thread_run->wakeup_time.tv_sec = -1;
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/* Unlock the mutex: */
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if ((unlock_mutex != 0) &&
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((rval = _mutex_cv_unlock(mutex)) != 0)) {
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/*
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* Cannot unlock the mutex, so remove
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* the running thread from the condition
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* variable queue:
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*/
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cond_queue_remove(*cond, _thread_run);
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/* Check for no more waiters: */
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if (TAILQ_FIRST(&(*cond)->c_queue) ==
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NULL)
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(*cond)->c_mutex = NULL;
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/* Unlock the condition variable structure: */
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_SPINUNLOCK(&(*cond)->lock);
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}
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else {
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/*
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* Don't unlock the mutex in the event
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* this thread has to be requeued in
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* condition variable queue:
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*/
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unlock_mutex = 0;
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/*
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* Schedule the next thread and unlock
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* the condition variable structure:
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*/
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_thread_kern_sched_state_unlock(PS_COND_WAIT,
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&(*cond)->lock, __FILE__, __LINE__);
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done = (seqno != (*cond)->c_seqno);
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if ((_thread_run->flags &
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PTHREAD_FLAGS_IN_CONDQ) != 0) {
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/*
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* Lock the condition variable
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* while removing the thread.
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*/
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_SPINLOCK(&(*cond)->lock);
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cond_queue_remove(*cond,
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_thread_run);
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/* Check for no more waiters: */
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if (TAILQ_FIRST(&(*cond)->c_queue) == NULL)
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(*cond)->c_mutex = NULL;
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_SPINUNLOCK(&(*cond)->lock);
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}
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/*
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* Save the interrupted flag; locking
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* the mutex will destroy it.
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*/
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interrupted = _thread_run->interrupted;
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/*
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* Note that even though this thread may have
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* been canceled, POSIX requires that the mutex
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* be reaquired prior to cancellation.
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*/
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rval = _mutex_cv_lock(mutex);
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}
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}
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break;
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/* Trap invalid condition variable types: */
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default:
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/* Unlock the condition variable structure: */
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_SPINUNLOCK(&(*cond)->lock);
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/* Return an invalid argument error: */
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rval = EINVAL;
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break;
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}
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if ((interrupted != 0) && (_thread_run->continuation != NULL))
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_thread_run->continuation((void *) _thread_run);
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} while ((done == 0) && (rval == 0));
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_thread_leave_cancellation_point();
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/* Return the completion status: */
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return (rval);
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}
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int
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pthread_cond_timedwait(pthread_cond_t * cond, pthread_mutex_t * mutex,
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const struct timespec * abstime)
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{
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int rval = 0;
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int done = 0;
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int interrupted = 0;
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int unlock_mutex = 1;
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int seqno;
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_thread_enter_cancellation_point();
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if (abstime == NULL || abstime->tv_sec < 0 || abstime->tv_nsec < 0 ||
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abstime->tv_nsec >= 1000000000)
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return (EINVAL);
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/*
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* If the condition variable is statically initialized, perform dynamic
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* initialization.
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*/
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if (*cond == NULL && (rval = pthread_cond_init(cond, NULL)) != 0)
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return (rval);
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/*
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* Enter a loop waiting for a condition signal or broadcast
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* to wake up this thread. A loop is needed in case the waiting
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* thread is interrupted by a signal to execute a signal handler.
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* It is not (currently) possible to remain in the waiting queue
|
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* while running a handler. Instead, the thread is interrupted
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* and backed out of the waiting queue prior to executing the
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* signal handler.
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*/
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do {
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/* Lock the condition variable structure: */
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_SPINLOCK(&(*cond)->lock);
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/*
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* If the condvar was statically allocated, properly
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* initialize the tail queue.
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*/
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if (((*cond)->c_flags & COND_FLAGS_INITED) == 0) {
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TAILQ_INIT(&(*cond)->c_queue);
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(*cond)->c_flags |= COND_FLAGS_INITED;
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}
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/* Process according to condition variable type: */
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switch ((*cond)->c_type) {
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/* Fast condition variable: */
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case COND_TYPE_FAST:
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if ((mutex == NULL) || (((*cond)->c_mutex != NULL) &&
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((*cond)->c_mutex != *mutex))) {
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/* Return invalid argument error: */
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rval = EINVAL;
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/* Unlock the condition variable structure: */
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_SPINUNLOCK(&(*cond)->lock);
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} else {
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/* Set the wakeup time: */
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_thread_run->wakeup_time.tv_sec =
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abstime->tv_sec;
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_thread_run->wakeup_time.tv_nsec =
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abstime->tv_nsec;
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/* Reset the timeout and interrupted flags: */
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_thread_run->timeout = 0;
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_thread_run->interrupted = 0;
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/*
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* Queue the running thread for the condition
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* variable:
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*/
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cond_queue_enq(*cond, _thread_run);
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/* Remember the mutex and sequence number: */
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(*cond)->c_mutex = *mutex;
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seqno = (*cond)->c_seqno;
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/* Unlock the mutex: */
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if ((unlock_mutex != 0) &&
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((rval = _mutex_cv_unlock(mutex)) != 0)) {
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/*
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* Cannot unlock the mutex, so remove
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* the running thread from the condition
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* variable queue:
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*/
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cond_queue_remove(*cond, _thread_run);
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/* Check for no more waiters: */
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if (TAILQ_FIRST(&(*cond)->c_queue) == NULL)
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(*cond)->c_mutex = NULL;
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/* Unlock the condition variable structure: */
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_SPINUNLOCK(&(*cond)->lock);
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} else {
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/*
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* Don't unlock the mutex in the event
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* this thread has to be requeued in
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* condition variable queue:
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*/
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unlock_mutex = 0;
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/*
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* Schedule the next thread and unlock
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* the condition variable structure:
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*/
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_thread_kern_sched_state_unlock(PS_COND_WAIT,
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&(*cond)->lock, __FILE__, __LINE__);
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done = (seqno != (*cond)->c_seqno);
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/*
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* Check if the wait timedout, was
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* interrupted (canceled), or needs to
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* be resumed after handling a signal.
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*/
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if ((_thread_run->timeout == 0) &&
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(_thread_run->interrupted == 0) &&
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(done != 0)) {
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/* Lock the mutex: */
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rval = _mutex_cv_lock(mutex);
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} else {
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/* Lock the CV structure: */
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_SPINLOCK(&(*cond)->lock);
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/*
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* The wait timed out; remove
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* the thread from the condition
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* variable queue:
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*/
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cond_queue_remove(*cond,
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_thread_run);
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/* Check for no more waiters: */
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if (TAILQ_FIRST(&(*cond)->c_queue) == NULL)
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(*cond)->c_mutex = NULL;
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/* Unock the CV structure: */
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_SPINUNLOCK(&(*cond)->lock);
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|
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/* Return a timeout error: */
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if (_thread_run->timeout != 0)
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rval = ETIMEDOUT;
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/*
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* Save the interrupted flag;
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* locking the mutex will
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* destroy it.
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*/
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interrupted = _thread_run->interrupted;
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|
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/*
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* Lock the mutex and ignore any
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* errors. Note that even though
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* this thread may have been
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* canceled, POSIX requires that
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* the mutex be reaquired prior
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* to cancellation.
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*/
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(void)_mutex_cv_lock(mutex);
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}
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}
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}
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break;
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|
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/* Trap invalid condition variable types: */
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default:
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/* Unlock the condition variable structure: */
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_SPINUNLOCK(&(*cond)->lock);
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|
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/* Return an invalid argument error: */
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rval = EINVAL;
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break;
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}
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|
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if ((interrupted != 0) && (_thread_run->continuation != NULL))
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_thread_run->continuation((void *) _thread_run);
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} while ((done == 0) && (rval == 0));
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|
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_thread_leave_cancellation_point();
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|
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/* Return the completion status: */
|
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return (rval);
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}
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|
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int
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pthread_cond_signal(pthread_cond_t * cond)
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{
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int rval = 0;
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pthread_t pthread;
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|
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if (cond == NULL)
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rval = EINVAL;
|
|
/*
|
|
* If the condition variable is statically initialized, perform dynamic
|
|
* initialization.
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|
*/
|
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else if (*cond != NULL || (rval = pthread_cond_init(cond, NULL) == 0)) {
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|
/*
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* Defer signals to protect the scheduling queues
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|
* from access by the signal handler:
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*/
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_thread_kern_sig_defer();
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/* Lock the condition variable structure: */
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_SPINLOCK(&(*cond)->lock);
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/* Process according to condition variable type: */
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switch ((*cond)->c_type) {
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/* Fast condition variable: */
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case COND_TYPE_FAST:
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/* Increment the sequence number: */
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(*cond)->c_seqno++;
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if ((pthread = cond_queue_deq(*cond)) != NULL) {
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/*
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* Unless the thread is currently suspended,
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* allow it to run. If the thread is suspended,
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* make a note that the thread isn't in a wait
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* queue any more.
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*/
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if (pthread->state != PS_SUSPENDED)
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PTHREAD_NEW_STATE(pthread,PS_RUNNING);
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else
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pthread->suspended = SUSP_NOWAIT;
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}
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|
|
/* Check for no more waiters: */
|
|
if (TAILQ_FIRST(&(*cond)->c_queue) == NULL)
|
|
(*cond)->c_mutex = NULL;
|
|
break;
|
|
|
|
/* Trap invalid condition variable types: */
|
|
default:
|
|
/* Return an invalid argument error: */
|
|
rval = EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* Unlock the condition variable structure: */
|
|
_SPINUNLOCK(&(*cond)->lock);
|
|
|
|
/*
|
|
* Undefer and handle pending signals, yielding if
|
|
* necessary:
|
|
*/
|
|
_thread_kern_sig_undefer();
|
|
}
|
|
|
|
/* Return the completion status: */
|
|
return (rval);
|
|
}
|
|
|
|
int
|
|
pthread_cond_broadcast(pthread_cond_t * cond)
|
|
{
|
|
int rval = 0;
|
|
pthread_t pthread;
|
|
|
|
if (cond == NULL)
|
|
rval = EINVAL;
|
|
/*
|
|
* If the condition variable is statically initialized, perform dynamic
|
|
* initialization.
|
|
*/
|
|
else if (*cond != NULL || (rval = pthread_cond_init(cond, NULL) == 0)) {
|
|
/*
|
|
* Defer signals to protect the scheduling queues
|
|
* from access by the signal handler:
|
|
*/
|
|
_thread_kern_sig_defer();
|
|
|
|
/* Lock the condition variable structure: */
|
|
_SPINLOCK(&(*cond)->lock);
|
|
|
|
/* Process according to condition variable type: */
|
|
switch ((*cond)->c_type) {
|
|
/* Fast condition variable: */
|
|
case COND_TYPE_FAST:
|
|
/* Increment the sequence number: */
|
|
(*cond)->c_seqno++;
|
|
|
|
/*
|
|
* Enter a loop to bring all threads off the
|
|
* condition queue:
|
|
*/
|
|
while ((pthread = cond_queue_deq(*cond)) != NULL) {
|
|
/*
|
|
* Unless the thread is currently suspended,
|
|
* allow it to run. If the thread is suspended,
|
|
* make a note that the thread isn't in a wait
|
|
* queue any more.
|
|
*/
|
|
if (pthread->state != PS_SUSPENDED)
|
|
PTHREAD_NEW_STATE(pthread,PS_RUNNING);
|
|
else
|
|
pthread->suspended = SUSP_NOWAIT;
|
|
}
|
|
|
|
/* There are no more waiting threads: */
|
|
(*cond)->c_mutex = NULL;
|
|
break;
|
|
|
|
/* Trap invalid condition variable types: */
|
|
default:
|
|
/* Return an invalid argument error: */
|
|
rval = EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* Unlock the condition variable structure: */
|
|
_SPINUNLOCK(&(*cond)->lock);
|
|
|
|
/*
|
|
* Undefer and handle pending signals, yielding if
|
|
* necessary:
|
|
*/
|
|
_thread_kern_sig_undefer();
|
|
}
|
|
|
|
/* Return the completion status: */
|
|
return (rval);
|
|
}
|
|
|
|
void
|
|
_cond_wait_backout(pthread_t pthread)
|
|
{
|
|
pthread_cond_t cond;
|
|
|
|
cond = pthread->data.cond;
|
|
if (cond != NULL) {
|
|
/*
|
|
* Defer signals to protect the scheduling queues
|
|
* from access by the signal handler:
|
|
*/
|
|
_thread_kern_sig_defer();
|
|
|
|
/* Lock the condition variable structure: */
|
|
_SPINLOCK(&cond->lock);
|
|
|
|
/* Process according to condition variable type: */
|
|
switch (cond->c_type) {
|
|
/* Fast condition variable: */
|
|
case COND_TYPE_FAST:
|
|
cond_queue_remove(cond, pthread);
|
|
|
|
/* Check for no more waiters: */
|
|
if (TAILQ_FIRST(&cond->c_queue) == NULL)
|
|
cond->c_mutex = NULL;
|
|
break;
|
|
|
|
default:
|
|
break;
|
|
}
|
|
|
|
/* Unlock the condition variable structure: */
|
|
_SPINUNLOCK(&cond->lock);
|
|
|
|
/*
|
|
* Undefer and handle pending signals, yielding if
|
|
* necessary:
|
|
*/
|
|
_thread_kern_sig_undefer();
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Dequeue a waiting thread from the head of a condition queue in
|
|
* descending priority order.
|
|
*/
|
|
static inline pthread_t
|
|
cond_queue_deq(pthread_cond_t cond)
|
|
{
|
|
pthread_t pthread;
|
|
|
|
while ((pthread = TAILQ_FIRST(&cond->c_queue)) != NULL) {
|
|
TAILQ_REMOVE(&cond->c_queue, pthread, sqe);
|
|
pthread->flags &= ~PTHREAD_FLAGS_IN_CONDQ;
|
|
if ((pthread->timeout == 0) && (pthread->interrupted == 0))
|
|
/*
|
|
* Only exit the loop when we find a thread
|
|
* that hasn't timed out or been canceled;
|
|
* those threads are already running and don't
|
|
* need their run state changed.
|
|
*/
|
|
break;
|
|
}
|
|
|
|
return(pthread);
|
|
}
|
|
|
|
/*
|
|
* Remove a waiting thread from a condition queue in descending priority
|
|
* order.
|
|
*/
|
|
static inline void
|
|
cond_queue_remove(pthread_cond_t cond, pthread_t pthread)
|
|
{
|
|
/*
|
|
* Because pthread_cond_timedwait() can timeout as well
|
|
* as be signaled by another thread, it is necessary to
|
|
* guard against removing the thread from the queue if
|
|
* it isn't in the queue.
|
|
*/
|
|
if (pthread->flags & PTHREAD_FLAGS_IN_CONDQ) {
|
|
TAILQ_REMOVE(&cond->c_queue, pthread, sqe);
|
|
pthread->flags &= ~PTHREAD_FLAGS_IN_CONDQ;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Enqueue a waiting thread to a condition queue in descending priority
|
|
* order.
|
|
*/
|
|
static inline void
|
|
cond_queue_enq(pthread_cond_t cond, pthread_t pthread)
|
|
{
|
|
pthread_t tid = TAILQ_LAST(&cond->c_queue, cond_head);
|
|
|
|
PTHREAD_ASSERT_NOT_IN_SYNCQ(pthread);
|
|
|
|
/*
|
|
* For the common case of all threads having equal priority,
|
|
* we perform a quick check against the priority of the thread
|
|
* at the tail of the queue.
|
|
*/
|
|
if ((tid == NULL) || (pthread->active_priority <= tid->active_priority))
|
|
TAILQ_INSERT_TAIL(&cond->c_queue, pthread, sqe);
|
|
else {
|
|
tid = TAILQ_FIRST(&cond->c_queue);
|
|
while (pthread->active_priority <= tid->active_priority)
|
|
tid = TAILQ_NEXT(tid, sqe);
|
|
TAILQ_INSERT_BEFORE(tid, pthread, sqe);
|
|
}
|
|
pthread->flags |= PTHREAD_FLAGS_IN_CONDQ;
|
|
pthread->data.cond = cond;
|
|
}
|
|
#endif
|