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nuttx/sched/pthread/pthread_condclockwait.c
Xiang Xiao acca9fcc3b sched/wdog: Remove MAX_WDOGPARMS and related stuff 
since the variable arguments are error prone and seldom used.

Signed-off-by: Xiang Xiao <xiaoxiang@xiaomi.com>
2020-08-14 08:19:50 -06:00

346 lines
10 KiB
C
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/****************************************************************************
* sched/pthread/pthread_condclockwait.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <nuttx/compiler.h>
#include <stdint.h>
#include <unistd.h>
#include <pthread.h>
#include <signal.h>
#include <time.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <nuttx/irq.h>
#include <nuttx/wdog.h>
#include <nuttx/signal.h>
#include <nuttx/cancelpt.h>
#include "sched/sched.h"
#include "pthread/pthread.h"
#include "clock/clock.h"
#include "signal/signal.h"
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: pthread_condtimedout
*
* Description:
* This function is called if the timeout elapses before
* the condition is signaled.
*
* Input Parameters:
* arg - the argument
*
* Returned Value:
* None
*
* Assumptions:
*
****************************************************************************/
static void pthread_condtimedout(wdparm_t arg)
{
pid_t pid = arg;
#ifdef HAVE_GROUP_MEMBERS
{
FAR struct tcb_s *tcb;
siginfo_t info;
/* The logic below if equivalent to nxsig_queue(), but uses
* nxsig_tcbdispatch() instead of nxsig_dispatch(). This avoids the
* group signal deliver logic and assures, instead, that the signal is
* delivered specifically to this thread that is known to be waiting on
* the signal.
*/
/* Get the waiting TCB. nxsched_get_tcb() might return NULL if the
* task has exited for some reason.
*/
tcb = nxsched_get_tcb(pid);
if (tcb)
{
/* Create the siginfo structure */
info.si_signo = SIGCONDTIMEDOUT;
info.si_code = SI_QUEUE;
info.si_errno = ETIMEDOUT;
info.si_value.sival_ptr = NULL;
#ifdef CONFIG_SCHED_HAVE_PARENT
info.si_pid = pid;
info.si_status = OK;
#endif
/* Process the receipt of the signal. The scheduler is not locked
* as is normally the case when this function is called because we
* are in a watchdog timer interrupt handler.
*/
nxsig_tcbdispatch(tcb, &info);
}
}
#else /* HAVE_GROUP_MEMBERS */
{
/* Things are a little easier if there are not group members. We can
* just use nxsig_queue().
*/
union sigval value;
/* Send the specified signal to the specified task. */
value.sival_ptr = NULL;
nxsig_queue(pid, SIGCONDTIMEDOUT, value);
}
#endif /* HAVE_GROUP_MEMBERS */
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: pthread_cond_clockwait
*
* Description:
* A thread can perform a timed wait on a condition variable.
*
* Input Parameters:
* cond - the condition variable to wait on
* mutex - the mutex that protects the condition variable
* clockid - The timing source to use in the conversion
* abstime - wait until this absolute time
*
* Returned Value:
* OK (0) on success; A non-zero errno value is returned on failure.
*
* Assumptions:
* Timing is of resolution 1 msec, with +/-1 millisecond accuracy.
*
****************************************************************************/
int pthread_cond_clockwait(FAR pthread_cond_t *cond,
FAR pthread_mutex_t *mutex,
clockid_t clockid,
FAR const struct timespec *abstime)
{
FAR struct tcb_s *rtcb = this_task();
irqstate_t flags;
sclock_t ticks;
int mypid = getpid();
int ret = OK;
int status;
sinfo("cond=0x%p mutex=0x%p abstime=0x%p\n", cond, mutex, abstime);
/* pthread_cond_clockwait() is a cancellation point */
enter_cancellation_point();
/* Make sure that non-NULL references were provided. */
if (!cond || !mutex)
{
ret = EINVAL;
}
/* Make sure that the caller holds the mutex */
else if (mutex->pid != mypid)
{
ret = EPERM;
}
/* If no wait time is provided, this function degenerates to
* the same behavior as pthread_cond_wait().
*/
else if (!abstime)
{
ret = pthread_cond_wait(cond, mutex);
}
else
{
sinfo("Give up mutex...\n");
/* We must disable pre-emption and interrupts here so that
* the time stays valid until the wait begins. This adds
* complexity because we assure that interrupts and
* pre-emption are re-enabled correctly.
*/
sched_lock();
flags = enter_critical_section();
/* Convert the timespec to clock ticks. We must disable pre-
* emption here so that this time stays valid until the wait
* begins.
*/
ret = clock_abstime2ticks(clockid, abstime, &ticks);
if (ret)
{
/* Restore interrupts (pre-emption will be enabled when
* we fall through the if/then/else)
*/
leave_critical_section(flags);
}
else
{
/* Check the absolute time to wait. If it is now or in the
* past, then just return with the timedout condition.
*/
if (ticks <= 0)
{
/* Restore interrupts and indicate that we have already
* timed out. (pre-emption will be enabled when we fall
* through the if/then/else
*/
leave_critical_section(flags);
ret = ETIMEDOUT;
}
else
{
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
uint8_t mflags;
#endif
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
uint8_t type;
int16_t nlocks;
#endif
/* Give up the mutex */
mutex->pid = -1;
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
mflags = mutex->flags;
#endif
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
type = mutex->type;
nlocks = mutex->nlocks;
#endif
ret = pthread_mutex_give(mutex);
if (ret != 0)
{
/* Restore interrupts (pre-emption will be enabled
* when we fall through the if/then/else)
*/
leave_critical_section(flags);
}
else
{
/* Start the watchdog */
wd_start(&rtcb->waitdog, ticks,
pthread_condtimedout, mypid);
/* Take the condition semaphore. Do not restore
* interrupts until we return from the wait. This is
* necessary to make sure that the watchdog timer and
* the condition wait are started atomically.
*/
status = nxsem_wait((FAR sem_t *)&cond->sem);
/* Did we get the condition semaphore. */
if (status < 0)
{
/* NO.. Handle the special case where the semaphore
* wait was awakened by the receipt of a signal --
* presumably the signal posted by
* pthread_condtimedout().
*/
if (status == -EINTR)
{
swarn("WARNING: Timedout!\n");
ret = ETIMEDOUT;
}
else
{
ret = status;
}
}
/* The interrupts stay disabled until after we sample
* the errno. This is because when debug is enabled
* and the console is used for debug output, then the
* errno can be altered by interrupt handling! (bad)
*/
leave_critical_section(flags);
}
/* Reacquire the mutex (retaining the ret). */
sinfo("Re-locking...\n");
status = pthread_mutex_take(mutex, NULL, false);
if (status == OK)
{
mutex->pid = mypid;
#ifndef CONFIG_PTHREAD_MUTEX_UNSAFE
mutex->flags = mflags;
#endif
#ifdef CONFIG_PTHREAD_MUTEX_TYPES
mutex->type = type;
mutex->nlocks = nlocks;
#endif
}
else if (ret == 0)
{
ret = status;
}
}
/* Re-enable pre-emption (It is expected that interrupts
* have already been re-enabled in the above logic)
*/
sched_unlock();
}
/* We no longer need the watchdog */
wd_cancel(&rtcb->waitdog);
}
leave_cancellation_point();
sinfo("Returning %d\n", ret);
return ret;
}
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