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; }