/************************************************************ * sig_received.c * * Copyright (C) 2007 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * 3. Neither the name Gregory Nutt nor the names of its contributors may be * used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. * ************************************************************/ /************************************************************ * Included Files ************************************************************/ #include #include #include #include #include #include #include #include "os_internal.h" #include "sem_internal.h" #include "sig_internal.h" /************************************************************ * Definitions ************************************************************/ /************************************************************ * Private Type Declarations ************************************************************/ /************************************************************ * Global Variables ************************************************************/ /************************************************************ * Private Variables ************************************************************/ /************************************************************ * Private Functions ************************************************************/ /************************************************************ * Function: sig_queueaction * * Description: * Queue a signal action for delivery to a task. * ************************************************************/ static int sig_queueaction(FAR _TCB *stcb, siginfo_t *info) { FAR sigactq_t *sigact; FAR sigq_t *sigq; irqstate_t saved_state; int ret = OK; sched_lock(); /* Find the sigaction associated with this signal */ sigact = sig_findaction(stcb, info->si_signo); /* Check if a valid signal handler is available and if the signal is * unblocked. NOTE: There is no default action. */ if ((sigact) && (sigact->act.sa_u._sa_sigaction)) { /* Allocate a new element for the signal queue. NOTE: sig_allocatependingsigaction * will force a system crash if it is unable to allocate memory for the * signal data */ sigq = sig_allocatependingsigaction(); if (!sigq) ret = ERROR; else { /* Populate the new signal queue element */ sigq->action.sighandler = sigact->act.sa_u._sa_sigaction; sigq->mask = sigact->act.sa_mask; memcpy(&sigq->info, info, sizeof(siginfo_t)); /* Put it at the end of the pending signals list */ saved_state = irqsave(); sq_addlast((FAR sq_entry_t*)sigq, &(stcb->sigpendactionq)); irqrestore(saved_state); } } sched_unlock(); return ret; } /************************************************************ * Function: sig_findpendingsignal * * Description: * Find a specified element in the pending signal list * ************************************************************/ static FAR sigpendq_t *sig_findpendingsignal(FAR _TCB *stcb, int signo) { FAR sigpendq_t *sigpend = NULL; irqstate_t saved_state; /* Verify the caller's sanity */ if (stcb) { /* Pending sigals can be added from interrupt level. */ saved_state = irqsave(); /* Seach the list for a sigpendion on this signal */ for(sigpend = (FAR sigpendq_t*)stcb->sigpendingq.head; (sigpend && sigpend->info.si_signo != signo); sigpend = sigpend->flink); irqrestore(saved_state); } return sigpend; } /************************************************************ * Function: sig_allocatependingsignal * * Description: * Allocate a pending signal list entry * ************************************************************/ static FAR sigpendq_t *sig_allocatependingsignal(void) { FAR sigpendq_t *sigpend; irqstate_t saved_state; /* Check if we were called from an interrupt handler. */ if (up_interrupt_context()) { /* Try to get the pending signal structure from the free list */ sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingsignal); /* If so, then try the special list of structures reserved for * interrupt handlers */ sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingirqsignal); } /* If we were not called from an interrupt handler, then we are * free to allocate pending action structures if necessary. */ else { /* Try to get the pending signal structure from the free list */ saved_state = irqsave(); sigpend = (FAR sigpendq_t*)sq_remfirst(&g_sigpendingsignal); irqrestore(saved_state); /* Check if we got one. */ if (!sigpend) { /* No... Allocate the pending signal */ if (!sigpend) { sigpend = (FAR sigpendq_t *)kmalloc((sizeof (sigpendq_t))); } /* Check if we got an allocated message */ if (sigpend) { sigpend->type = SIG_ALLOC_DYN; } } } return sigpend; } /************************************************************ * Function: sig_addpendingsignal * * Description: * Add the specified signal to the signal pending list. * NOTE: This function will queue only one entry for each * pending signal. This was done intentionally so that a * run-away sender cannot consume all of memory. ************************************************************/ static FAR sigpendq_t *sig_addpendingsignal(FAR _TCB *stcb, siginfo_t *info) { FAR sigpendq_t *sigpend; irqstate_t saved_state; /* Check if the signal is already pending */ sigpend = sig_findpendingsignal(stcb, info->si_signo); if (sigpend) { /* The signal is already pending... retain only one copy */ memcpy(&sigpend->info, info, sizeof(siginfo_t)); } /* No... There is nothing pending for this signo */ else { /* Allocate a new pending signal entry */ sigpend = sig_allocatependingsignal(); if (sigpend) { /* Put the signal information into the allocated structure */ memcpy(&sigpend->info, info, sizeof(siginfo_t)); /* Add the structure to the pending signal list */ saved_state = irqsave(); sq_addlast((FAR sq_entry_t*)sigpend, &stcb->sigpendingq); irqrestore(saved_state); } } return sigpend; } /************************************************************ * Public Functions ************************************************************/ /************************************************************ * Function: sig_received * * Description: * All signals received the task (whatever the source) go * through this function to be processed. This function * is responsible for: * * - Determining if the signal is blocked. * - Queuing and dispatching signal actions * - Unblocking tasks that are waiting for signals * - Queuing pending signals. * ************************************************************/ int sig_received(FAR _TCB *stcb, siginfo_t *info) { irqstate_t saved_state; int ret = ERROR; dbg("sig_received: TCB=0x%08x signo=%d code=%d value=%d\n", stcb, info->si_signo, info->si_code, info->si_value.sival_int); if (stcb && info) { ret = OK; /****** MASKED SIGNAL HANDLING ******/ /* Check if the signal is masked -- if it is, it will be added to the * list of pending signals. */ if (sigismember(&stcb->sigprocmask, info->si_signo)) { /* Check if the task is waiting for this pending signal. If so, * then unblock it. This must be performed in a critical section * because signals can be queued from the interrupt level. */ saved_state = irqsave(); if (stcb->task_state == TSTATE_WAIT_SIG && sigismember(&stcb->sigwaitmask, info->si_signo)) { memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t)); stcb->sigwaitmask = NULL_SIGNAL_SET; up_unblock_task(stcb); irqrestore(saved_state); } /* Its not one we are waiting for... Add it to the list of pending * signals. */ else { irqrestore(saved_state); if (!sig_addpendingsignal(stcb, info)) { PANIC(OSERR_FAILEDTOADDSIGNAL); } } } /****** UNMASKED SIGNAL HANDLING ******/ else { /* Queue any sigaction's requested by this task. */ ret = sig_queueaction(stcb, info); /* Then schedule execution of the signal handling action on * the recipients thread. */ up_schedule_sigaction(stcb, sig_deliver); /* Check if the task is waiting for an unmasked signal. If so, * then unblock it. This must be performed in a critical section * because signals can be queued from the interrupt level. */ saved_state = irqsave(); if (stcb->task_state == TSTATE_WAIT_SIG) { memcpy(&stcb->sigunbinfo, info, sizeof(siginfo_t)); stcb->sigwaitmask = NULL_SIGNAL_SET; up_unblock_task(stcb); } irqrestore(saved_state); /* If the task neither was waiting for the signal nor had a signal * handler attached to the signal, then the default action is * simply to ignore the signal */ } /****** OTHER SIGNAL HANDLING ******/ /* If the task is blocked waiting for a semaphore, then that * task must be unblocked when a signal is received. */ if (stcb->task_state == TSTATE_WAIT_SEM) { sem_waitirq(stcb); } /* If the task is blocked waiting on a message queue, then that * task must be unblocked when a signal is received. */ /* NOT YET IMPLEMENTED. */ } return ret; }