nuttx/sched/signal/sig_action.c

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/****************************************************************************
* sched/signal/sig_action.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 <stdint.h>
#include <stdbool.h>
#include <signal.h>
#include <sched.h>
#include <assert.h>
#include <errno.h>
#include <nuttx/irq.h>
#include <nuttx/queue.h>
#include <nuttx/spinlock.h>
#include "sched/sched.h"
#include "group/group.h"
#include "signal/signal.h"
/****************************************************************************
* Private Data
****************************************************************************/
static spinlock_t g_sigaction_spin;
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: nxsig_alloc_actionblock
*
* Description:
* Allocate a block of signal actions and place them
* on the free list.
*
****************************************************************************/
static void nxsig_alloc_actionblock(void)
{
FAR sigactq_t *sigact;
irqstate_t flags;
int i;
/* Allocate a block of signal actions */
sigact = kmm_malloc((sizeof(sigactq_t)) * NUM_SIGNAL_ACTIONS);
if (sigact != NULL)
{
flags = spin_lock_irqsave(&g_sigaction_spin);
for (i = 0; i < NUM_SIGNAL_ACTIONS; i++)
{
sq_addlast((FAR sq_entry_t *)sigact++, &g_sigfreeaction);
}
spin_unlock_irqrestore(&g_sigaction_spin, flags);
}
}
/****************************************************************************
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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* Name: nxsig_alloc_action
*
* Description:
* Allocate a new element for a sigaction queue
*
****************************************************************************/
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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static FAR sigactq_t *nxsig_alloc_action(void)
{
FAR sigactq_t *sigact;
irqstate_t flags;
/* Try to get the signal action structure from the free list */
flags = spin_lock_irqsave(&g_sigaction_spin);
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sigact = (FAR sigactq_t *)sq_remfirst(&g_sigfreeaction);
spin_unlock_irqrestore(&g_sigaction_spin, flags);
/* Check if we got one. */
while (!sigact)
{
/* Add another block of signal actions to the list */
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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nxsig_alloc_actionblock();
/* And try again */
flags = spin_lock_irqsave(&g_sigaction_spin);
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sigact = (FAR sigactq_t *)sq_remfirst(&g_sigfreeaction);
spin_unlock_irqrestore(&g_sigaction_spin, flags);
}
return sigact;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: nxsig_action and sigaction
*
* Description:
* This function allows the calling process to examine and/or specify the
* action to be associated with a specific signal.
*
* The structure sigaction, used to describe an action to be taken, is
* defined to include the following members:
*
* - sa_u.sa_handler: Pointer to a signal-catching function
* - sa_u.sa_sigaction: Alternative form of the signal-catching function
* - sa_mask: An additional set of signals to be blocked during execution
* of a signal catching function
* - sa_flags. Special flags to affect the behavior of a signal.
*
* If the argument 'act' is not NULL, it points to a structure specifying
* the action to be associated with the specified signal. If the argument
* 'oact' is not NULL, the action previously associated with the signal
* is stored in the location pointed to by the argument 'oact.'
*
* When a signal is caught by a signal-catching function installed by
* sigaction() function, a new signal mask is calculated and installed for
* the duration of the signal-catching function. This mask is formed by
* taking the union of the current signal mask and the value of the
* sa_mask for the signal being delivered and then including the signal
* being delivered. If and when the user's signal handler returns, the
* original signal mask is restored.
*
* Once an action is installed for a specific signal, it remains installed
* until another action is explicitly requested by another call to
* sigaction().
*
* nxsig_action() is an internal version of sigaction that adds an
* additional parameter, force, that is used to set default signal actions
* (which may not normally be settable). nxsig_action() does not alter the
* errno variable.
*
* Input Parameters:
* sig - Signal of interest
* act - Location of new handler
* oact - Location to store only handler
* force - Force setup of the signal handler, even if it cannot normally
* be caught or ignored (nxsig_action only)
*
* Returned Value:
* nxsig_action:
* Zero (OK) is returned on success; a negated errno value is returned
* on failure
* sigaction:
* Zero (OK) is returned on success; -1 (ERROR) is returned on any
* failure if the signal number is invalid with the errno set
* appropriately
*
* Assumptions:
*
* POSIX Compatibility:
* - If CONFIG_SIG_DEFAULT is not defined, then there are no default actions
* so the special value SIG_DFL is treated like SIG_IGN.
* - All sa_flags in struct sigaction of act input are ignored (all
* treated like SA_SIGINFO). The one exception is if
* CONFIG_SCHED_CHILD_STATUS is defined; then SA_NOCLDWAIT is supported but
* only for SIGCHLD
*
****************************************************************************/
int nxsig_action(int signo, FAR const struct sigaction *act,
FAR struct sigaction *oact, bool force)
{
FAR struct tcb_s *rtcb = this_task();
FAR struct task_group_s *group;
FAR sigactq_t *sigact;
_sa_handler_t handler;
/* Since sigactions can only be installed from the running thread of
* execution, no special precautions should be necessary.
*/
DEBUGASSERT(rtcb != NULL && rtcb->group != NULL);
group = rtcb->group;
/* Verify the signal number */
if (!GOOD_SIGNO(signo))
{
return -EINVAL;
}
#ifdef CONFIG_SIG_DEFAULT
/* Check if the user is trying to catch or ignore a signal that cannot be
* caught or ignored.
*/
if (act != NULL && !force && act->sa_handler != SIG_DFL &&
!nxsig_iscatchable(signo))
{
return -EINVAL;
}
#endif
/* Find the signal in the signal action queue */
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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sigact = nxsig_find_action(group, signo);
/* Return the old sigaction value if so requested */
if (oact != NULL)
{
#ifdef CONFIG_SIG_DEFAULT
if (nxsig_isdefault(rtcb, signo))
{
/* Return SIG_DFL if the default signal is attached */
oact->sa_handler = SIG_DFL;
oact->sa_flags = SA_SIGINFO;
sigemptyset(&oact->sa_mask);
}
else
#endif
if (sigact)
{
/* Return the old signal action */
oact->sa_handler = sigact->act.sa_handler;
oact->sa_mask = sigact->act.sa_mask;
oact->sa_flags = sigact->act.sa_flags;
}
else
{
/* There isn't an old value */
oact->sa_handler = NULL;
oact->sa_flags = 0;
sigemptyset(&oact->sa_mask);
}
}
/* If the argument act is a null pointer, signal handling is unchanged;
* thus, the call can be used to inquire about the current handling of
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* a given signal.
*/
if (act == NULL)
{
return OK;
}
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
/* Handle a special case. Retention of child status can be suppressed
* if signo == SIGCHLD and sa_flags == SA_NOCLDWAIT.
*
* POSIX.1 leaves it unspecified whether a SIGCHLD signal is generated
* when a child process terminates. In NuttX, a SIGCHLD signal is
* generated in this case; but in some other implementations, it may not
* be.
*/
if (signo == SIGCHLD && (act->sa_flags & SA_NOCLDWAIT) != 0)
{
irqstate_t flags;
/* We do require a critical section to muck with the TCB values that
* can be modified by the child thread.
*/
flags = enter_critical_section();
/* Mark that status should be not be retained */
rtcb->group->tg_flags |= GROUP_FLAG_NOCLDWAIT;
/* Free all pending exit status */
group_remove_children(rtcb->group);
leave_critical_section(flags);
}
#endif
handler = act->sa_handler;
#ifdef CONFIG_SIG_DEFAULT
/* If the caller is setting the handler to SIG_DFL, then we need to
* replace this with the correct, internal default signal action handler.
*/
if (handler == SIG_DFL)
{
/* nxsig_default() may returned SIG_IGN */
handler = nxsig_default(rtcb, signo, true);
}
else
{
/* We will be replacing the default action (or ignoring it) */
nxsig_default(rtcb, signo, false);
}
#endif
/* Handle the case where no sigaction is supplied (SIG_IGN) */
if (handler == SIG_IGN)
{
/* Do we still have a sigaction container from the previous setting? */
if (sigact)
{
/* Yes.. Remove it from signal action queue */
sq_rem((FAR sq_entry_t *)sigact, &group->tg_sigactionq);
/* And deallocate it */
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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nxsig_release_action(sigact);
}
}
/* A sigaction has been supplied */
else
{
/* Do we still have a sigaction container from the previous setting?
* If so, then re-use for the new signal action.
*/
if (sigact == NULL)
{
/* No.. Then we need to allocate one for the new action. */
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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sigact = nxsig_alloc_action();
/* An error has occurred if we could not allocate the sigaction */
if (!sigact)
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{
return -ENOMEM;
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}
/* Put the signal number in the queue entry */
sigact->signo = (uint8_t)signo;
/* Add the new sigaction to signal action queue */
sq_addlast((FAR sq_entry_t *)sigact, &group->tg_sigactionq);
}
/* Set the new sigaction */
sigact->act.sa_handler = handler;
sigact->act.sa_mask = act->sa_mask;
sigact->act.sa_flags = act->sa_flags;
sigact->act.sa_user = act->sa_user;
}
return OK;
}
int sigaction(int signo, FAR const struct sigaction *act,
FAR struct sigaction *oact)
{
int ret;
/* nxsig_action() does all of the work */
ret = nxsig_action(signo, act, oact, false);
if (ret < 0)
{
set_errno(-ret);
return ERROR;
}
return OK;
}
/****************************************************************************
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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* Name: nxsig_release_action
*
* Description:
* Deallocate a sigaction Q entry
*
****************************************************************************/
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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void nxsig_release_action(FAR sigactq_t *sigact)
{
irqstate_t flags;
/* Just put it back on the free list */
flags = spin_lock_irqsave(&g_sigaction_spin);
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sq_addlast((FAR sq_entry_t *)sigact, &g_sigfreeaction);
spin_unlock_irqrestore(&g_sigaction_spin, flags);
}