int sigaction(int signo, FAR const struct sigaction *act, FAR struct sigaction *oact)
{
FAR struct tcb_s *rtcb = (FAR struct tcb_s*)g_readytorun.head;
FAR sigactq_t *sigact;
/* Since sigactions can only be installed from the running thread of
* execution, no special precautions should be necessary.
*/
/* Verify the signal number */
if (!GOOD_SIGNO(signo))
{
set_errno(EINVAL);
return ERROR;
}
/* Find the signal in the sigactionq */
sigact = sig_findaction(rtcb, signo);
/* Return the old sigaction value if so requested */
if (oact)
{
if (sigact)
{
COPY_SIGACTION(oact, &sigact->act);
}
else
{
/* There isn't an old value */
oact->sa_u._sa_handler = NULL;
oact->sa_mask = NULL_SIGNAL_SET;
oact->sa_flags = 0;
}
}
/* If the argument act is a null pointer, signal handling is unchanged;
* thus, the call can be used to enquire about the current handling of
* a given signal.
*/
if (!act)
{
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 = irqsave();
/* Mark that status should be not be retained */
rtcb->group->tg_flags |= GROUP_FLAG_NOCLDWAIT;
/* Free all pending exit status */
group_removechildren(rtcb->group);
irqrestore(flags);
}
#endif
/* Handle the case where no sigaction is supplied (SIG_IGN) */
if (act->sa_u._sa_handler == SIG_IGN)
{
/* Do we still have a sigaction container from the previous setting? */
if (sigact)
{
/* Yes.. Remove it from sigactionq */
sq_rem((FAR sq_entry_t*)sigact, &rtcb->sigactionq);
/* And deallocate it */
sig_releaseaction(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)
{
/* No.. Then we need to allocate one for the new action. */
sigact = sig_allocateaction();
/* An error has occurred if we could not allocate the sigaction */
if (!sigact)
{
set_errno(ENOMEM);
return ERROR;
}
/* Put the signal number in the queue entry */
sigact->signo = (uint8_t)signo;
/* Add the new sigaction to sigactionq */
sq_addlast((FAR sq_entry_t*)sigact, &rtcb->sigactionq);
}
/* Set the new sigaction */
COPY_SIGACTION(&sigact->act, act);
}
return OK;
}
int sigaction(int signo, FAR const struct sigaction *act, FAR struct sigaction *oact)
{
FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head;
FAR sigactq_t *sigact;
int ret = ERROR; /* Assume failure */
/* Since sigactions can only be installed from the running thread of
* execution, no special precautions should be necessary.
*/
/* Verify the signal */
if (GOOD_SIGNO(signo))
{
ret = OK; /* Assume success */
/* Find the signal in the sigactionq */
sigact = sig_findaction(rtcb, signo);
/* Return the old sigaction value if so requested */
if (oact)
{
if (sigact)
{
COPY_SIGACTION(oact, &sigact->act);
}
else
{
/* There isn't an old value */
oact->sa_u._sa_handler = NULL;
oact->sa_mask = NULL_SIGNAL_SET;
oact->sa_flags = 0;
}
}
/* If no sigaction was found, but one is needed, then
* allocate one.
*/
if (!sigact && act && act->sa_u._sa_handler)
{
sigact = sig_allocateaction();
/* An error has occurred if we could not allocate the sigaction */
if (!sigact)
{
ret = ERROR;
}
else
{
/* Put the signal number in the queue entry */
sigact->signo = (uint8_t)signo;
/* Add the new sigaction to sigactionq */
sq_addlast((FAR sq_entry_t*)sigact, &rtcb->sigactionq);
}
}
/* Set the new sigaction if so requested */
if ((sigact) && (act))
{
/* Check if it is a request to install a new handler */
if (act->sa_u._sa_handler)
{
COPY_SIGACTION(&sigact->act, act);
}
/* No.. It is a request to remove the old handler */
else
{
/* Remove the old sigaction from sigactionq */
sq_rem((FAR sq_entry_t*)sigact, &rtcb->sigactionq);
/* And deallocate it */
sig_releaseaction(sigact);
}
}
}
return ret;
}