386 lines
12 KiB
C
386 lines
12 KiB
C
/************************************************************
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* sig_received.c
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*
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* Copyright (C) 2007 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
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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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*
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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
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name Gregory Nutt nor the names of its contributors may be
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* 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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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************************************************************/
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/************************************************************
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* Included Files
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************************************************************/
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#include <sys/types.h>
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#include <string.h>
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#include <signal.h>
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#include <unistd.h>
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#include <sched.h>
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#include <debug.h>
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#include <nuttx/arch.h>
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#include "os_internal.h"
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#include "sem_internal.h"
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#include "sig_internal.h"
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/************************************************************
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* Definitions
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************************************************************/
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/************************************************************
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* Private Type Declarations
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************************************************************/
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/************************************************************
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* Global Variables
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************************************************************/
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/************************************************************
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* Private Variables
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************************************************************/
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/************************************************************
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* Private Functions
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************************************************************/
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/************************************************************
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* Function: sig_queueaction
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*
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* Description:
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* Queue a signal action for delivery to a task.
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*
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************************************************************/
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static int sig_queueaction(FAR _TCB *stcb, siginfo_t *info)
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{
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FAR sigactq_t *sigact;
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FAR sigq_t *sigq;
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irqstate_t saved_state;
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int ret = OK;
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sched_lock();
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/* Find the sigaction associated with this signal */
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sigact = sig_findaction(stcb, info->si_signo);
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/* Check if a valid signal handler is available and if the signal is
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* unblocked. NOTE: There is no default action.
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*/
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if ((sigact) && (sigact->act.sa_u._sa_sigaction))
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{
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/* Allocate a new element for the signal queue. NOTE: sig_allocatependingsigaction
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* will force a system crash if it is unable to allocate memory for the
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* signal data */
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sigq = sig_allocatependingsigaction();
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if (!sigq) ret = ERROR;
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else
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{
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/* Populate the new signal queue element */
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sigq->action.sighandler = sigact->act.sa_u._sa_sigaction;
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sigq->mask = sigact->act.sa_mask;
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memcpy(&sigq->info, info, sizeof(siginfo_t));
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/* Put it at the end of the pending signals list */
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saved_state = irqsave();
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sq_addlast((FAR sq_entry_t*)sigq, &(stcb->sigpendactionq));
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irqrestore(saved_state);
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}
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}
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sched_unlock();
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return ret;
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}
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/************************************************************
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* Function: sig_findpendingsignal
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*
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* Description:
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* Find a specified element in the pending signal list
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*
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************************************************************/
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static FAR sigpendq_t *sig_findpendingsignal(FAR _TCB *stcb, int signo)
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{
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FAR sigpendq_t *sigpend = NULL;
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irqstate_t saved_state;
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/* Verify the caller's sanity */
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if (stcb)
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{
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/* Pending sigals can be added from interrupt level. */
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saved_state = irqsave();
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/* Seach the list for a sigpendion on this signal */
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for(sigpend = (FAR sigpendq_t*)stcb->sigpendingq.head;
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(sigpend && sigpend->info.si_signo != signo);
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sigpend = sigpend->flink);
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irqrestore(saved_state);
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}
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return sigpend;
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}
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/************************************************************
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* Function: sig_allocatependingsignal
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*
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* Description:
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* Allocate a pending signal list entry
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*
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************************************************************/
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static FAR sigpendq_t *sig_allocatependingsignal(void)
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{
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FAR sigpendq_t *sigpend;
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irqstate_t saved_state;
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/* Check if we were called from an interrupt handler. */
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if (up_interrupt_context())
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{
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/* Try to get the pending signal structure from the free list */
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sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingsignal);
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/* If so, then try the special list of structures reserved for
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* interrupt handlers
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*/
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sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingirqsignal);
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}
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/* If we were not called from an interrupt handler, then we are
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* free to allocate pending action structures if necessary. */
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else
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{
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/* Try to get the pending signal structure from the free list */
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saved_state = irqsave();
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sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingsignal);
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irqrestore(saved_state);
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/* Check if we got one. */
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if (!sigpend)
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{
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/* No... Allocate the pending signal */
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if (!sigpend)
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{
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sigpend = (FAR sigpendq_t *)kmalloc((sizeof (sigpendq_t)));
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}
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/* Check if we got an allocated message */
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if (sigpend)
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{
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sigpend->type = SIG_ALLOC_DYN;
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}
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}
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}
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return sigpend;
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}
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/************************************************************
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* Function: sig_addpendingsignal
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*
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* Description:
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* Add the specified signal to the signal pending list.
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* NOTE: This function will queue only one entry for each
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* pending signal. This was done intentionally so that a
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* run-away sender cannot consume all of memory.
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************************************************************/
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static FAR sigpendq_t *sig_addpendingsignal(FAR _TCB *stcb, siginfo_t *info)
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{
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FAR sigpendq_t *sigpend;
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irqstate_t saved_state;
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/* Check if the signal is already pending */
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sigpend = sig_findpendingsignal(stcb, info->si_signo);
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if (sigpend)
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{
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/* The signal is already pending... retain only one copy */
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memcpy(&sigpend->info, info, sizeof(siginfo_t));
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}
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/* No... There is nothing pending for this signo */
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else
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{
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/* Allocate a new pending signal entry */
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sigpend = sig_allocatependingsignal();
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if (sigpend)
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{
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/* Put the signal information into the allocated structure */
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memcpy(&sigpend->info, info, sizeof(siginfo_t));
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/* Add the structure to the pending signal list */
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saved_state = irqsave();
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sq_addlast((FAR sq_entry_t*)sigpend, &stcb->sigpendingq);
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irqrestore(saved_state);
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}
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}
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return sigpend;
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}
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/************************************************************
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* Public Functions
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************************************************************/
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/************************************************************
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* Function: sig_received
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*
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* Description:
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* All signals received the task (whatever the source) go
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* through this function to be processed. This function
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* is responsible for:
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*
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* - Determining if the signal is blocked.
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* - Queuing and dispatching signal actions
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* - Unblocking tasks that are waiting for signals
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* - Queuing pending signals.
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*
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************************************************************/
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int sig_received(FAR _TCB *stcb, siginfo_t *info)
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{
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irqstate_t saved_state;
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int ret = ERROR;
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dbg("sig_received: TCB=0x%08x signo=%d code=%d value=%d\n",
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stcb, info->si_signo, info->si_code, info->si_value.sival_int);
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if (stcb && info)
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{
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ret = OK;
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/****** MASKED SIGNAL HANDLING ******/
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/* Check if the signal is masked -- if it is, it will be added to the
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* list of pending signals.
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*/
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if (sigismember(&stcb->sigprocmask, info->si_signo))
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{
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/* Check if the task is waiting for this pending signal. If so,
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* then unblock it. This must be performed in a critical section
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* because signals can be queued from the interrupt level.
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*/
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saved_state = irqsave();
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if (stcb->task_state == TSTATE_WAIT_SIG &&
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sigismember(&stcb->sigwaitmask, info->si_signo))
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{
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memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
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stcb->sigwaitmask = NULL_SIGNAL_SET;
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up_unblock_task(stcb);
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irqrestore(saved_state);
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}
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/* Its not one we are waiting for... Add it to the list of pending
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* signals.
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*/
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else
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{
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irqrestore(saved_state);
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if (!sig_addpendingsignal(stcb, info))
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{
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PANIC(OSERR_FAILEDTOADDSIGNAL);
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}
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}
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}
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/****** UNMASKED SIGNAL HANDLING ******/
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else
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{
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/* Queue any sigaction's requested by this task. */
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ret = sig_queueaction(stcb, info);
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/* Then schedule execution of the signal handling action on
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* the recipients thread.
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*/
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up_schedule_sigaction(stcb, sig_deliver);
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/* Check if the task is waiting for an unmasked signal. If so,
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* then unblock it. This must be performed in a critical section
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* because signals can be queued from the interrupt level.
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*/
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saved_state = irqsave();
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if (stcb->task_state == TSTATE_WAIT_SIG)
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{
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memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t));
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stcb->sigwaitmask = NULL_SIGNAL_SET;
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up_unblock_task(stcb);
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}
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irqrestore(saved_state);
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/* If the task neither was waiting for the signal nor had a signal
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* handler attached to the signal, then the default action is
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* simply to ignore the signal */
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}
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/****** OTHER SIGNAL HANDLING ******/
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/* If the task is blocked waiting for a semaphore, then that
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* task must be unblocked when a signal is received.
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*/
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if (stcb->task_state == TSTATE_WAIT_SEM)
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{
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sem_waitirq(stcb);
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}
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/* If the task is blocked waiting on a message queue, then that
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* task must be unblocked when a signal is received.
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*/
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/* NOT YET IMPLEMENTED. */
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}
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return ret;
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}
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