/************************************************************
* sig_timedwait.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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. Neither the name Gregory Nutt nor the names of its contributors may be
* used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
************************************************************/
/************************************************************
* Included Files
************************************************************/
#include <sys/types.h>
#include <signal.h>
#include <time.h>
#include <wdog.h>
#include <assert.h>
#include <debug.h>
#include <sched.h>
#include <nuttx/arch.h>
#include "os_internal.h"
#include "sig_internal.h"
#include "clock_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Global Variables
************************************************************/
/************************************************************
* Private Variables
************************************************************/
/************************************************************
* Private Functionss
************************************************************/
/************************************************************
* Function: sig_timeout
*
* Description:
* A timeout elapsed while waiting for signals to be queued.
************************************************************/
static void sig_timeout(int itcb, int parm2, int parm3, int parm4)
{
_TCB *wtcb = (_TCB*)itcb;
if (!wtcb)
{
PANIC(OSERR_TIMEOUTNOTCB);
}
/* There may be a race condition -- make sure the task is
* still waiting for a signal
*/
if (wtcb->task_state == TSTATE_WAIT_SIG)
{
wtcb->sigunbinfo.si_signo = ERROR;
wtcb->sigunbinfo.si_code = SI_TIMEOUT;
wtcb->sigunbinfo.si_value.sival_int = 0;
up_unblock_task(wtcb);
}
}
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: sigtimedwait
*
* Description:
* This function selects the pending signal set specified
* by the argument set. If multiple signals are pending
* in set, it will remove and return the lowest numbered
* one. If no signals in set are pending at the time of
* the call, the calling process will be suspended until
* one of the signals in set becomes pending, OR until
* the process is interrupted by an unblocked signal, OR
* until the time interval specified by timeout (if any),
* has expired. If timeout is NULL, then the timeout
* interval is forever.
*
* If the info argument is non-NULL, the selected signal
* number is stored in the si_signo member and the cause
* of the signal is store in the si_code emember. The
* content of si_value is only meaningful if the signal was
* generated by sigqueue().
*
* The following values for si_code are defined in signal.h:
* SI_QUEUE - Signal sent from sigqueue
* SI_MESGQ - Signal generated by arrival of a message on an
* empty message queue
* SI_NOWAIT - Signal already pending -- don't know how sent
* SI_TIMEOUT - No Signal, restarted by timeout
*
* Parameters:
* set - The pending signal set.
* info - The returned value
* timeout - The amount of time to wait
*
* Return Value:
* Signal number that cause the wait to be terminated, otherwise
* -1 (ERROR) is returned.
*
* Assumptions:
*
************************************************************/
int sigtimedwait(const sigset_t *set, struct siginfo *info,
const struct timespec *timeout)
{
_TCB *rtcb = (_TCB*)g_readytorun.head;
sigset_t intersection;
sigpendq_t *sigpend;
WDOG_ID wdog;
uint32 saved_state;
sint32 waitticks;
int ret = ERROR;
sched_lock(); /* Not necessary */
/* Several operations must be performed below: We must determine if any
* signal is pending and, if not, wait for the signal. Since signals can
* be posted from the interrupt level, there is a race condition that
* can only be eliminated by disabling interrupts!
*/
saved_state = irqsave();
/* Check if there is a pending signal corresponding to one of the
* signals in the pending signal set argument.
*/
intersection = *set & sig_pendingset(rtcb);
if (intersection != NULL_SIGNAL_SET)
{
/* One or more of the signals in intersections is sufficient to cause
* us to not wait. Pick the lowest numbered signal and mark it not
* pending.
*/
sigpend = sig_removependingsignal(rtcb, sig_lowest(&intersection));
if (!sigpend)
{
PANIC(OSERR_NOPENDINGSIGNAL);
}
/* Return the signal info to the caller if so requested */
if (info) *info = sigpend->info;
/* Then dispose of the pending signal structure properly */
sig_releasependingsignal(sigpend);
irqrestore(saved_state);
/* The return value is the number of the signal that awakened us */
ret = info->si_signo;
}
/* We will have to wait for a signal to be posted to this task. */
else
{
/* Save the set of pending signals to wait for */
rtcb->sigwaitmask = *set;
/* Check if we should wait for the timeout */
if (timeout)
{
/* Convert the timespec to milliseconds */
waitticks = MSEC2TICK(timeout->tv_sec * MSEC_PER_SEC
+ timeout->tv_nsec / NSEC_PER_MSEC);
/* Create a watchdog */
wdog = wd_create();
if (wdog)
{
/* Start the watchdog */
wd_start(wdog, waitticks, (wdentry_t)sig_timeout,
(int)rtcb, 0, 0, 0);
/* Now wait for either the signal or the watchdog */
up_block_task(rtcb, TSTATE_WAIT_SIG);
/* We no longer need the watchdog */
wd_delete(wdog);
}
}
/* No timeout, just wait */
else
{
/* And wait until one of the unblocked signals is posted */
up_block_task(rtcb, TSTATE_WAIT_SIG);
}
/* We are running again, clear the sigwaitmask */
rtcb->sigwaitmask = NULL_SIGNAL_SET;
/* When we awaken, the cause will be in the TCB. Return the signal
* info to the caller if so requested
*/
if (info)
{
*info = rtcb->sigunbinfo;
}
irqrestore(saved_state);
/* The return value is the number of the signal that awakened us */
ret = info->si_signo;
}
sched_unlock();
return ret;
}
