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incubator-nuttx/sched/sig_received.c

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/************************************************************
* sig_received.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 <string.h>
#include <signal.h>
#include <unistd.h>
#include <sched.h>
#include <debug.h>
#include <nuttx/arch.h>
#include "os_internal.h"
#include "sem_internal.h"
#include "sig_internal.h"
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Global Variables
************************************************************/
/************************************************************
* Private Variables
************************************************************/
/************************************************************
* Private Functions
************************************************************/
/************************************************************
* Function: sig_queueaction
*
* Description:
* Queue a signal action for delivery to a task.
*
************************************************************/
static int sig_queueaction(FAR _TCB *stcb, siginfo_t *info)
{
FAR sigactq_t *sigact;
FAR sigq_t *sigq;
irqstate_t saved_state;
int ret = OK;
sched_lock();
/* Find the sigaction associated with this signal */
sigact = sig_findaction(stcb, info->si_signo);
/* Check if a valid signal handler is available and if the signal is
* unblocked. NOTE: There is no default action.
*/
if ((sigact) && (sigact->act.sa_u._sa_sigaction))
{
/* Allocate a new element for the signal queue. NOTE: sig_allocatependingsigaction
* will force a system crash if it is unable to allocate memory for the
* signal data */
sigq = sig_allocatependingsigaction();
if (!sigq) ret = ERROR;
else
{
/* Populate the new signal queue element */
sigq->action.sighandler = sigact->act.sa_u._sa_sigaction;
sigq->mask = sigact->act.sa_mask;
memcpy(&sigq->info, info, sizeof(siginfo_t));
/* Put it at the end of the pending signals list */
saved_state = irqsave();
sq_addlast((FAR sq_entry_t*)sigq, &(stcb->sigpendactionq));
irqrestore(saved_state);
}
}
sched_unlock();
return ret;
}
/************************************************************
* Function: sig_findpendingsignal
*
* Description:
* Find a specified element in the pending signal list
*
************************************************************/
static FAR sigpendq_t *sig_findpendingsignal(FAR _TCB *stcb, int signo)
{
FAR sigpendq_t *sigpend = NULL;
irqstate_t saved_state;
/* Verify the caller's sanity */
if (stcb)
{
/* Pending sigals can be added from interrupt level. */
saved_state = irqsave();
/* Seach the list for a sigpendion on this signal */
for(sigpend = (FAR sigpendq_t*)stcb->sigpendingq.head;
(sigpend && sigpend->info.si_signo != signo);
sigpend = sigpend->flink);
irqrestore(saved_state);
}
return sigpend;
}
/************************************************************
* Function: sig_allocatependingsignal
*
* Description:
* Allocate a pending signal list entry
*
************************************************************/
static FAR sigpendq_t *sig_allocatependingsignal(void)
{
FAR sigpendq_t *sigpend;
irqstate_t saved_state;
/* Check if we were called from an interrupt handler. */
if (up_interrupt_context())
{
/* Try to get the pending signal structure from the free list */
sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingsignal);
/* If so, then try the special list of structures reserved for
* interrupt handlers
*/
sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingirqsignal);
}
/* If we were not called from an interrupt handler, then we are
* free to allocate pending action structures if necessary. */
else
{
/* Try to get the pending signal structure from the free list */
saved_state = irqsave();
sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingsignal);
irqrestore(saved_state);
/* Check if we got one. */
if (!sigpend)
{
/* No... Allocate the pending signal */
if (!sigpend)
{
sigpend = (FAR sigpendq_t *)kmalloc((sizeof (sigpendq_t)));
}
/* Check if we got an allocated message */
if (sigpend)
{
sigpend->type = SIG_ALLOC_DYN;
}
}
}
return sigpend;
}
/************************************************************
* Function: sig_addpendingsignal
*
* Description:
* Add the specified signal to the signal pending list.
* NOTE: This function will queue only one entry for each
* pending signal. This was done intentionally so that a
* run-away sender cannot consume all of memory.
************************************************************/
static FAR sigpendq_t *sig_addpendingsignal(FAR _TCB *stcb, siginfo_t *info)
{
FAR sigpendq_t *sigpend;
irqstate_t saved_state;
/* Check if the signal is already pending */
sigpend = sig_findpendingsignal(stcb, info->si_signo);
if (sigpend)
{
/* The signal is already pending... retain only one copy */
memcpy(&sigpend->info, info, sizeof(siginfo_t));
}
/* No... There is nothing pending for this signo */
else
{
/* Allocate a new pending signal entry */
sigpend = sig_allocatependingsignal();
if (sigpend)
{
/* Put the signal information into the allocated structure */
memcpy(&sigpend->info, info, sizeof(siginfo_t));
/* Add the structure to the pending signal list */
saved_state = irqsave();
sq_addlast((FAR sq_entry_t*)sigpend, &stcb->sigpendingq);
irqrestore(saved_state);
}
}
return sigpend;
}
/************************************************************
* Public Functions
************************************************************/
/************************************************************
* Function: sig_received
*
* Description:
* All signals received the task (whatever the source) go
* through this function to be processed. This function
* is responsible for:
*
* - Determining if the signal is blocked.
* - Queuing and dispatching signal actions
* - Unblocking tasks that are waiting for signals
* - Queuing pending signals.
*
************************************************************/
int sig_received(FAR _TCB *stcb, siginfo_t *info)
{
irqstate_t saved_state;
int ret = ERROR;
dbg("sig_received: TCB=0x%08x signo=%d code=%d value=%d\n",
stcb, info->si_signo, info->si_code, info->si_value.sival_int);
if (stcb && info)
{
ret = OK;
/****** MASKED SIGNAL HANDLING ******/
/* Check if the signal is masked -- if it is, it will be added to the
* list of pending signals.
*/
if (sigismember(&stcb->sigprocmask, info->si_signo))
{
/* Check if the task is waiting for this pending signal. If so,
* then unblock it. This must be performed in a critical section
* because signals can be queued from the interrupt level.
*/
saved_state = irqsave();
if (stcb->task_state == TSTATE_WAIT_SIG &&
sigismember(&stcb->sigwaitmask, info->si_signo))
{
memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
stcb->sigwaitmask = NULL_SIGNAL_SET;
up_unblock_task(stcb);
irqrestore(saved_state);
}
/* Its not one we are waiting for... Add it to the list of pending
* signals.
*/
else
{
irqrestore(saved_state);
if (!sig_addpendingsignal(stcb, info))
{
PANIC(OSERR_FAILEDTOADDSIGNAL);
}
}
}
/****** UNMASKED SIGNAL HANDLING ******/
else
{
/* Queue any sigaction's requested by this task. */
ret = sig_queueaction(stcb, info);
/* Then schedule execution of the signal handling action on
* the recipients thread.
*/
up_schedule_sigaction(stcb, sig_deliver);
/* Check if the task is waiting for an unmasked signal. If so,
* then unblock it. This must be performed in a critical section
* because signals can be queued from the interrupt level.
*/
saved_state = irqsave();
if (stcb->task_state == TSTATE_WAIT_SIG)
{
memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
stcb->sigwaitmask = NULL_SIGNAL_SET;
up_unblock_task(stcb);
}
irqrestore(saved_state);
/* If the task neither was waiting for the signal nor had a signal
* handler attached to the signal, then the default action is
* simply to ignore the signal */
}
/****** OTHER SIGNAL HANDLING ******/
/* If the task is blocked waiting for a semaphore, then that
* task must be unblocked when a signal is received.
*/
if (stcb->task_state == TSTATE_WAIT_SEM)
{
sem_waitirq(stcb);
}
/* If the task is blocked waiting on a message queue, then that
* task must be unblocked when a signal is received.
*/
/* NOT YET IMPLEMENTED. */
}
return ret;
}
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