freebsd-dev/lib/libc_r/uthread/uthread_priority_queue.c
Jason Evans 0a3fa43c7e Implement continuations to correctly handle [sig|_]longjmp() inside of a
signal handler.  Explicitly check for jumps to anywhere other than the
current stack, since such jumps are undefined according to POSIX.

While we're at it, convert thread cancellation to use continuations, since
it's cleaner than the original cancellation code.

Avoid delivering a signal to a thread twice.  This was a pre-existing bug,
but was likely unexposed until these other changes were made.

Defer signals generated by pthread_kill() so that they can be delivered on
the appropriate stack.  deischen claims that this is unnecessary, which is
likely true, but without this change, pthread_kill() can cause undefined
priority queue states and/or PANICs in [sig|_]longjmp(), so I'm leaving
this in for now.  To compile this code out and exercise the bug, define
the _NO_UNDISPATCH cpp macro.  Defining _PTHREADS_INVARIANTS as well will
cause earlier crashes.

PR:			kern/14685
Collaboration with:	deischen
2000-01-19 07:04:50 +00:00

336 lines
8.6 KiB
C

/*
* Copyright (c) 1998 Daniel Eischen <eischen@vigrid.com>.
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Daniel Eischen.
* 4. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY DANIEL EISCHEN AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD$
*/
#include <stdlib.h>
#include <sys/queue.h>
#include <string.h>
#ifdef _THREAD_SAFE
#include <pthread.h>
#include "pthread_private.h"
/* Prototypes: */
static void pq_insert_prio_list(pq_queue_t *pq, int prio);
#if defined(_PTHREADS_INVARIANTS)
static int _pq_active = 0;
#define _PQ_IN_SCHEDQ (PTHREAD_FLAGS_IN_PRIOQ | PTHREAD_FLAGS_IN_WAITQ | PTHREAD_FLAGS_IN_WORKQ)
#define _PQ_SET_ACTIVE() _pq_active = 1
#define _PQ_CLEAR_ACTIVE() _pq_active = 0
#define _PQ_ASSERT_ACTIVE(msg) do { \
if (_pq_active == 0) \
PANIC(msg); \
} while (0)
#define _PQ_ASSERT_INACTIVE(msg) do { \
if (_pq_active != 0) \
PANIC(msg); \
} while (0)
#define _PQ_ASSERT_IN_WAITQ(thrd, msg) do { \
if (((thrd)->flags & PTHREAD_FLAGS_IN_WAITQ) == 0) \
PANIC(msg); \
} while (0)
#define _PQ_ASSERT_IN_PRIOQ(thrd, msg) do { \
if (((thrd)->flags & PTHREAD_FLAGS_IN_PRIOQ) == 0) \
PANIC(msg); \
} while (0)
#define _PQ_ASSERT_NOT_QUEUED(thrd, msg) do { \
if ((thrd)->flags & _PQ_IN_SCHEDQ) \
PANIC(msg); \
} while (0)
#else
#define _PQ_SET_ACTIVE()
#define _PQ_CLEAR_ACTIVE()
#define _PQ_ASSERT_ACTIVE(msg)
#define _PQ_ASSERT_INACTIVE(msg)
#define _PQ_ASSERT_IN_WAITQ(thrd, msg)
#define _PQ_ASSERT_IN_PRIOQ(thrd, msg)
#define _PQ_ASSERT_NOT_QUEUED(thrd, msg)
#define _PQ_CHECK_PRIO()
#endif
int
_pq_alloc(pq_queue_t *pq, int minprio, int maxprio)
{
int ret = 0;
int prioslots = maxprio - minprio + 1;
if (pq == NULL)
ret = -1;
/* Create the priority queue with (maxprio - minprio + 1) slots: */
else if ((pq->pq_lists =
(pq_list_t *) malloc(sizeof(pq_list_t) * prioslots)) == NULL)
ret = -1;
else {
/* Remember the queue size: */
pq->pq_size = prioslots;
ret = _pq_init(pq);
}
return (ret);
}
int
_pq_init(pq_queue_t *pq)
{
int i, ret = 0;
if ((pq == NULL) || (pq->pq_lists == NULL))
ret = -1;
else {
/* Initialize the queue for each priority slot: */
for (i = 0; i < pq->pq_size; i++) {
TAILQ_INIT(&pq->pq_lists[i].pl_head);
pq->pq_lists[i].pl_prio = i;
pq->pq_lists[i].pl_queued = 0;
}
/* Initialize the priority queue: */
TAILQ_INIT(&pq->pq_queue);
_PQ_CLEAR_ACTIVE();
}
return (ret);
}
void
_pq_remove(pq_queue_t *pq, pthread_t pthread)
{
int prio = pthread->active_priority;
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_INACTIVE("_pq_remove: pq_active");
_PQ_SET_ACTIVE();
_PQ_ASSERT_IN_PRIOQ(pthread, "_pq_remove: Not in priority queue");
/*
* Remove this thread from priority list. Note that if
* the priority list becomes empty, it is not removed
* from the priority queue because another thread may be
* added to the priority list (resulting in a needless
* removal/insertion). Priority lists are only removed
* from the priority queue when _pq_first is called.
*/
TAILQ_REMOVE(&pq->pq_lists[prio].pl_head, pthread, pqe);
/* This thread is now longer in the priority queue. */
pthread->flags &= ~PTHREAD_FLAGS_IN_PRIOQ;
_PQ_CLEAR_ACTIVE();
}
void
_pq_insert_head(pq_queue_t *pq, pthread_t pthread)
{
int prio = pthread->active_priority;
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_INACTIVE("_pq_insert_head: pq_active");
_PQ_SET_ACTIVE();
_PQ_ASSERT_NOT_QUEUED(pthread,
"_pq_insert_head: Already in priority queue");
TAILQ_INSERT_HEAD(&pq->pq_lists[prio].pl_head, pthread, pqe);
if (pq->pq_lists[prio].pl_queued == 0)
/* Insert the list into the priority queue: */
pq_insert_prio_list(pq, prio);
/* Mark this thread as being in the priority queue. */
pthread->flags |= PTHREAD_FLAGS_IN_PRIOQ;
_PQ_CLEAR_ACTIVE();
}
void
_pq_insert_tail(pq_queue_t *pq, pthread_t pthread)
{
int prio = pthread->active_priority;
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_INACTIVE("_pq_insert_tail: pq_active");
_PQ_SET_ACTIVE();
_PQ_ASSERT_NOT_QUEUED(pthread,
"_pq_insert_tail: Already in priority queue");
TAILQ_INSERT_TAIL(&pq->pq_lists[prio].pl_head, pthread, pqe);
if (pq->pq_lists[prio].pl_queued == 0)
/* Insert the list into the priority queue: */
pq_insert_prio_list(pq, prio);
/* Mark this thread as being in the priority queue. */
pthread->flags |= PTHREAD_FLAGS_IN_PRIOQ;
_PQ_CLEAR_ACTIVE();
}
pthread_t
_pq_first(pq_queue_t *pq)
{
pq_list_t *pql;
pthread_t pthread = NULL;
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_INACTIVE("_pq_first: pq_active");
_PQ_SET_ACTIVE();
while (((pql = TAILQ_FIRST(&pq->pq_queue)) != NULL) &&
(pthread == NULL)) {
if ((pthread = TAILQ_FIRST(&pql->pl_head)) == NULL) {
/*
* The priority list is empty; remove the list
* from the queue.
*/
TAILQ_REMOVE(&pq->pq_queue, pql, pl_link);
/* Mark the list as not being in the queue: */
pql->pl_queued = 0;
}
}
_PQ_CLEAR_ACTIVE();
return (pthread);
}
static void
pq_insert_prio_list(pq_queue_t *pq, int prio)
{
pq_list_t *pql;
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_ACTIVE("pq_insert_prio_list: pq_active");
/*
* The priority queue is in descending priority order. Start at
* the beginning of the queue and find the list before which the
* new list should be inserted.
*/
pql = TAILQ_FIRST(&pq->pq_queue);
while ((pql != NULL) && (pql->pl_prio > prio))
pql = TAILQ_NEXT(pql, pl_link);
/* Insert the list: */
if (pql == NULL)
TAILQ_INSERT_TAIL(&pq->pq_queue, &pq->pq_lists[prio], pl_link);
else
TAILQ_INSERT_BEFORE(pql, &pq->pq_lists[prio], pl_link);
/* Mark this list as being in the queue: */
pq->pq_lists[prio].pl_queued = 1;
}
#if defined(_PTHREADS_INVARIANTS)
void
_waitq_insert(pthread_t pthread)
{
pthread_t tid;
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_INACTIVE("_waitq_insert: pq_active");
_PQ_SET_ACTIVE();
_PQ_ASSERT_NOT_QUEUED(pthread, "_waitq_insert: Already in queue");
if (pthread->wakeup_time.tv_sec == -1)
TAILQ_INSERT_TAIL(&_waitingq, pthread, pqe);
else {
tid = TAILQ_FIRST(&_waitingq);
while ((tid != NULL) && (tid->wakeup_time.tv_sec != -1) &&
((tid->wakeup_time.tv_sec < pthread->wakeup_time.tv_sec) ||
((tid->wakeup_time.tv_sec == pthread->wakeup_time.tv_sec) &&
(tid->wakeup_time.tv_nsec <= pthread->wakeup_time.tv_nsec))))
tid = TAILQ_NEXT(tid, pqe);
if (tid == NULL)
TAILQ_INSERT_TAIL(&_waitingq, pthread, pqe);
else
TAILQ_INSERT_BEFORE(tid, pthread, pqe);
}
pthread->flags |= PTHREAD_FLAGS_IN_WAITQ;
_PQ_CLEAR_ACTIVE();
}
void
_waitq_remove(pthread_t pthread)
{
/*
* Make some assertions when debugging is enabled:
*/
_PQ_ASSERT_INACTIVE("_waitq_remove: pq_active");
_PQ_SET_ACTIVE();
_PQ_ASSERT_IN_WAITQ(pthread, "_waitq_remove: Not in queue");
TAILQ_REMOVE(&_waitingq, pthread, pqe);
pthread->flags &= ~PTHREAD_FLAGS_IN_WAITQ;
_PQ_CLEAR_ACTIVE();
}
void
_waitq_setactive(void)
{
_PQ_ASSERT_INACTIVE("_waitq_setactive: pq_active");
_PQ_SET_ACTIVE();
}
void
_waitq_clearactive(void)
{
_PQ_ASSERT_ACTIVE("_waitq_clearactive: ! pq_active");
_PQ_CLEAR_ACTIVE();
}
#endif
#endif