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;
}
static inline void group_release(FAR struct task_group_s *group)
{
/* Free all un-reaped child exit status */
#if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS)
group_removechildren(group);
#endif
#ifndef CONFIG_DISABLE_SIGNALS
/* Release pending signals */
sig_release(group);
#endif
#ifndef CONFIG_DISABLE_PTHREAD
/* Release pthread resources */
pthread_release(group);
#endif
#if CONFIG_NFILE_DESCRIPTORS > 0
/* Free all file-related resources now. We really need to close files as
* soon as possible while we still have a functioning task.
*/
/* Free resources held by the file descriptor list */
files_releaselist(&group->tg_filelist);
#if CONFIG_NFILE_STREAMS > 0
/* Free resource held by the stream list */
lib_stream_release(group);
#endif /* CONFIG_NFILE_STREAMS */
#endif /* CONFIG_NFILE_DESCRIPTORS */
#if CONFIG_NSOCKET_DESCRIPTORS > 0
/* Free resource held by the socket list */
net_releaselist(&group->tg_socketlist);
#endif /* CONFIG_NSOCKET_DESCRIPTORS */
#ifndef CONFIG_DISABLE_ENVIRON
/* Release all shared environment variables */
env_release(group);
#endif
#ifndef CONFIG_DISABLE_MQUEUE
/* Close message queues opened by members of the group */
mq_release(group);
#endif
#if defined(CONFIG_BUILD_KERNEL) && defined(CONFIG_MM_SHM)
/* Release any resource held by shared memory virtual page allocator */
(void)shm_group_release(group);
#endif
#ifdef CONFIG_ARCH_ADDRENV
/* Destroy the group address environment */
(void)up_addrenv_destroy(&group->tg_addrenv);
/* Mark no address environment */
g_gid_current = 0;
#endif
#if defined(HAVE_GROUP_MEMBERS) || defined(CONFIG_ARCH_ADDRENV)
/* Remove the group from the list of groups */
group_remove(group);
#endif
#ifdef HAVE_GROUP_MEMBERS
/* Release the members array */
if (group->tg_members)
{
sched_kfree(group->tg_members);
group->tg_members = NULL;
}
#endif
#if CONFIG_NFILE_STREAMS > 0 && defined(CONFIG_MM_KERNEL_HEAP)
/* In a flat, single-heap build. The stream list is part of the
* group structure and, hence will be freed when the group structure
* is freed. Otherwise, it is separately allocated an must be
* freed here.
*/
# if defined(CONFIG_BUILD_PROTECTED)
/* In the protected build, the task's stream list is always allocated
* and freed from the single, global user allocator.
*/
sched_ufree(group->tg_streamlist);
# elif defined(CONFIG_BUILD_KERNEL)
/* In the kernel build, the unprivileged process' stream list will be
* allocated from with its per-process, private user heap. But in that
* case, there is no reason to do anything here: That allocation resides
* in the user heap which which be completely freed when we destroy the
* process' address environment.
*/
if ((group->tg_flags & GROUP_FLAG_PRIVILEGED) != 0)
{
/* But kernel threads are different in this build configuration: Their
* stream lists were allocated from the common, global kernel heap and
* must explicitly freed here.
*/
sched_kfree(group->tg_streamlist);
}
# endif
#endif
#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
/* If there are threads waiting for this group to be freed, then we cannot
* yet free the memory resources. Instead just mark the group deleted
* and wait for those threads complete their waits.
*/
if (group->tg_nwaiters > 0)
{
group->tg_flags |= GROUP_FLAG_DELETED;
}
else
#endif
{
/* Release the group container itself */
sched_kfree(group);
}
}
