| /**************************************************************************** |
| * sched/signal/sig_timedwait.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 <nuttx/compiler.h> |
| |
| #include <stdint.h> |
| #include <string.h> |
| #include <signal.h> |
| #include <time.h> |
| #include <assert.h> |
| #include <debug.h> |
| #include <sched.h> |
| #include <errno.h> |
| |
| #include <nuttx/irq.h> |
| #include <nuttx/arch.h> |
| #include <nuttx/wdog.h> |
| #include <nuttx/signal.h> |
| #include <nuttx/cancelpt.h> |
| #include <nuttx/queue.h> |
| |
| #include "sched/sched.h" |
| #include "signal/signal.h" |
| #include "clock/clock.h" |
| |
| /**************************************************************************** |
| * Pre-processor Definitions |
| ****************************************************************************/ |
| |
| /* These are special values of si_signo that mean that either the wait was |
| * awakened with a timeout, or the wait was canceled... not the receipt of a |
| * signal. |
| */ |
| |
| #define SIG_CANCEL_TIMEOUT 0xfe |
| #define SIG_WAIT_TIMEOUT 0xff |
| |
| /**************************************************************************** |
| * Private Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: nxsig_timeout |
| * |
| * Description: |
| * A timeout elapsed while waiting for signals to be queued. |
| * |
| * Assumptions: |
| * This function executes in the context of the timer interrupt handler. |
| * Local interrupts are assumed to be disabled on entry. |
| * |
| ****************************************************************************/ |
| |
| static void nxsig_timeout(wdparm_t arg) |
| { |
| FAR struct tcb_s *wtcb = (FAR struct tcb_s *)(uintptr_t)arg; |
| #ifdef CONFIG_SMP |
| irqstate_t flags; |
| |
| /* We must be in a critical section in order to call up_switch_context() |
| * below. If we are running on a single CPU architecture, then we know |
| * interrupts a disabled an there is no need to explicitly call |
| * enter_critical_section(). However, in the SMP case, |
| * enter_critical_section() does much more than just disable interrupts on |
| * the local CPU; it also manages spinlocks to assure the stability of the |
| * TCB that we are manipulating. |
| */ |
| |
| flags = enter_critical_section(); |
| #endif |
| |
| /* There may be a race condition -- make sure the task is |
| * still waiting for a signal |
| */ |
| |
| if (wtcb->task_state == TSTATE_WAIT_SIG) |
| { |
| FAR struct tcb_s *rtcb = this_task(); |
| |
| if (wtcb->sigunbinfo != NULL) |
| { |
| wtcb->sigunbinfo->si_signo = SIG_WAIT_TIMEOUT; |
| wtcb->sigunbinfo->si_code = SI_TIMER; |
| wtcb->sigunbinfo->si_errno = ETIMEDOUT; |
| wtcb->sigunbinfo->si_value.sival_int = 0; |
| #ifdef CONFIG_SCHED_HAVE_PARENT |
| wtcb->sigunbinfo->si_pid = 0; /* Not applicable */ |
| wtcb->sigunbinfo->si_status = OK; |
| #endif |
| } |
| |
| /* Remove the task from waitting list */ |
| |
| dq_rem((FAR dq_entry_t *)wtcb, list_waitingforsignal()); |
| |
| /* Add the task to ready-to-run task list, and |
| * perform the context switch if one is needed |
| */ |
| |
| if (nxsched_add_readytorun(wtcb)) |
| { |
| up_switch_context(wtcb, rtcb); |
| } |
| } |
| |
| #ifdef CONFIG_SMP |
| leave_critical_section(flags); |
| #endif |
| } |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: nxsig_wait_irq |
| * |
| * Description: |
| * An error event has occurred and the signal wait must be terminated with |
| * an error. |
| * |
| ****************************************************************************/ |
| |
| #ifdef CONFIG_CANCELLATION_POINTS |
| void nxsig_wait_irq(FAR struct tcb_s *wtcb, int errcode) |
| { |
| #ifdef CONFIG_SMP |
| irqstate_t flags; |
| |
| /* We must be in a critical section in order to call up_switch_context() |
| * below. If we are running on a single CPU architecture, then we know |
| * interrupts a disabled an there is no need to explicitly call |
| * enter_critical_section(). However, in the SMP case, |
| * enter_critical_section() does much more than just disable interrupts on |
| * the local CPU; it also manages spinlocks to assure the stability of the |
| * TCB that we are manipulating. |
| */ |
| |
| flags = enter_critical_section(); |
| #endif |
| |
| /* There may be a race condition -- make sure the task is |
| * still waiting for a signal |
| */ |
| |
| if (wtcb->task_state == TSTATE_WAIT_SIG) |
| { |
| FAR struct tcb_s *rtcb = this_task(); |
| |
| if (wtcb->sigunbinfo != NULL) |
| { |
| wtcb->sigunbinfo->si_signo = SIG_CANCEL_TIMEOUT; |
| wtcb->sigunbinfo->si_code = SI_USER; |
| wtcb->sigunbinfo->si_errno = errcode; |
| wtcb->sigunbinfo->si_value.sival_int = 0; |
| #ifdef CONFIG_SCHED_HAVE_PARENT |
| wtcb->sigunbinfo->si_pid = 0; /* Not applicable */ |
| wtcb->sigunbinfo->si_status = OK; |
| #endif |
| } |
| |
| /* Remove the task from waitting list */ |
| |
| dq_rem((FAR dq_entry_t *)wtcb, list_waitingforsignal()); |
| |
| /* Add the task to ready-to-run task list, and |
| * perform the context switch if one is needed |
| */ |
| |
| if (nxsched_add_readytorun(wtcb)) |
| { |
| up_switch_context(wtcb, rtcb); |
| } |
| } |
| |
| #ifdef CONFIG_SMP |
| leave_critical_section(flags); |
| #endif |
| } |
| #endif /* CONFIG_CANCELLATION_POINTS */ |
| |
| /**************************************************************************** |
| * Name: nxsig_timedwait |
| * |
| * Description: |
| * This function selects the pending signal set specified by the argument |
| * set. If multiple signals are pending in set, it will remove and return |
| * the lowest numbered one. If no signals in set are pending at the time |
| * of the call, the calling process will be suspended until one of the |
| * signals in set becomes pending, OR until the process is interrupted by |
| * an unblocked signal, OR until the time interval specified by timeout |
| * (if any), has expired. If timeout is NULL, then the timeout interval |
| * is forever. |
| * |
| * If the info argument is non-NULL, the selected signal number is stored |
| * in the si_signo member and the cause of the signal is stored in the |
| * si_code member. The content of si_value is only meaningful if the |
| * signal was generated by sigqueue() (or nxsig_queue). |
| * |
| * This is an internal OS interface. It is functionally equivalent to |
| * sigtimedwait() except that: |
| * |
| * - It is not a cancellation point, and |
| * - It does not modify the errno value. |
| * |
| * Input Parameters: |
| * set - The pending signal set. |
| * info - The returned value (may be NULL). |
| * timeout - The amount of time to wait (may be NULL) |
| * |
| * Returned Value: |
| * This is an internal OS interface and should not be used by applications. |
| * It follows the NuttX internal error return policy: Zero (OK) is |
| * returned on success. A negated errno value is returned on failure. |
| * |
| * EAGAIN - No signal specified by set was generated within the specified |
| * timeout period. |
| * EINTR - The wait was interrupted by an unblocked, caught signal. |
| * |
| ****************************************************************************/ |
| |
| int nxsig_timedwait(FAR const sigset_t *set, FAR struct siginfo *info, |
| FAR const struct timespec *timeout) |
| { |
| FAR struct tcb_s *rtcb = this_task(); |
| sigset_t intersection; |
| FAR sigpendq_t *sigpend; |
| irqstate_t flags; |
| sclock_t waitticks; |
| bool switch_needed; |
| siginfo_t sinfo; |
| int ret; |
| |
| DEBUGASSERT(set != NULL); |
| |
| /* Several operations must be performed below: We must determine if any |
| * signal is pending and, if not, wait for the signal. Since signals can |
| * be posted from the interrupt level, there is a race condition that |
| * can only be eliminated by disabling interrupts! |
| */ |
| |
| flags = enter_critical_section(); |
| |
| /* Check if there is a pending signal corresponding to one of the |
| * signals in the pending signal set argument. |
| */ |
| |
| intersection = nxsig_pendingset(rtcb); |
| sigandset(&intersection, &intersection, set); |
| if (!sigisemptyset(&intersection)) |
| { |
| /* One or more of the signals in intersections is sufficient to cause |
| * us to not wait. Pick the lowest numbered signal and mark it not |
| * pending. |
| */ |
| |
| sigpend = nxsig_remove_pendingsignal(rtcb, |
| nxsig_lowest(&intersection)); |
| DEBUGASSERT(sigpend); |
| |
| /* Return the signal info to the caller if so requested */ |
| |
| if (info != NULL) |
| { |
| memcpy(info, &sigpend->info, sizeof(struct siginfo)); |
| } |
| |
| /* The return value is the number of the signal that awakened us */ |
| |
| ret = sigpend->info.si_signo; |
| |
| /* Then dispose of the pending signal structure properly */ |
| |
| nxsig_release_pendingsignal(sigpend); |
| leave_critical_section(flags); |
| } |
| |
| /* We will have to wait for a signal to be posted to this task. */ |
| |
| else |
| { |
| #ifdef CONFIG_CANCELLATION_POINTS |
| /* nxsig_timedwait() is not a cancellation point, but it may be called |
| * from a cancellation point. So if a cancellation is pending, we |
| * must exit immediately without waiting. |
| */ |
| |
| if (check_cancellation_point()) |
| { |
| /* If there is a pending cancellation, then do not perform |
| * the wait. Exit now with ECANCELED. |
| */ |
| |
| leave_critical_section(flags); |
| return -ECANCELED; |
| } |
| #endif |
| |
| rtcb->sigunbinfo = (info == NULL) ? &sinfo : info; |
| |
| /* Check if we should wait for the timeout */ |
| |
| if (timeout != NULL) |
| { |
| /* Convert the timespec to system clock ticks, making sure that |
| * the resulting delay is greater than or equal to the requested |
| * time in nanoseconds. |
| */ |
| |
| #ifdef CONFIG_SYSTEM_TIME64 |
| waitticks = ((uint64_t)timeout->tv_sec * NSEC_PER_SEC + |
| (uint64_t)timeout->tv_nsec + NSEC_PER_TICK - 1) / |
| NSEC_PER_TICK; |
| #else |
| uint32_t waitmsec; |
| |
| DEBUGASSERT(timeout->tv_sec < UINT32_MAX / MSEC_PER_SEC); |
| waitmsec = timeout->tv_sec * MSEC_PER_SEC + |
| (timeout->tv_nsec + NSEC_PER_MSEC - 1) / NSEC_PER_MSEC; |
| waitticks = MSEC2TICK(waitmsec); |
| #endif |
| |
| if (waitticks > 0) |
| { |
| /* Save the set of pending signals to wait for */ |
| |
| rtcb->sigwaitmask = *set; |
| |
| /* Start the watchdog */ |
| |
| wd_start(&rtcb->waitdog, waitticks, |
| nxsig_timeout, (uintptr_t)rtcb); |
| |
| /* Now wait for either the signal or the watchdog, but |
| * first, make sure this is not the idle task, |
| * descheduling that isn't going to end well. |
| */ |
| |
| DEBUGASSERT(!is_idle_task(rtcb)); |
| |
| /* Remove the tcb task from the ready-to-run list. */ |
| |
| switch_needed = nxsched_remove_readytorun(rtcb, true); |
| |
| /* Add the task to the specified blocked task list */ |
| |
| rtcb->task_state = TSTATE_WAIT_SIG; |
| dq_addlast((FAR dq_entry_t *)rtcb, list_waitingforsignal()); |
| |
| /* Now, perform the context switch if one is needed */ |
| |
| if (switch_needed) |
| { |
| up_switch_context(this_task(), rtcb); |
| } |
| |
| /* We no longer need the watchdog */ |
| |
| wd_cancel(&rtcb->waitdog); |
| } |
| else |
| { |
| rtcb->sigunbinfo = NULL; |
| |
| leave_critical_section(flags); |
| return -EAGAIN; |
| } |
| } |
| |
| /* No timeout, just wait */ |
| |
| else |
| { |
| /* Save the set of pending signals to wait for */ |
| |
| rtcb->sigwaitmask = *set; |
| |
| /* And wait until one of the unblocked signals is posted, |
| * but first make sure this is not the idle task, |
| * descheduling that isn't going to end well. |
| */ |
| |
| DEBUGASSERT(!is_idle_task(rtcb)); |
| |
| /* Remove the tcb task from the ready-to-run list. */ |
| |
| switch_needed = nxsched_remove_readytorun(rtcb, true); |
| |
| /* Add the task to the specified blocked task list */ |
| |
| rtcb->task_state = TSTATE_WAIT_SIG; |
| dq_addlast((FAR dq_entry_t *)rtcb, list_waitingforsignal()); |
| |
| /* Now, perform the context switch if one is needed */ |
| |
| if (switch_needed) |
| { |
| up_switch_context(this_task(), rtcb); |
| } |
| } |
| |
| /* We are running again, clear the sigwaitmask */ |
| |
| sigemptyset(&rtcb->sigwaitmask); |
| |
| /* When we awaken, the cause will be in the TCB. Get the signal number |
| * or timeout) that awakened us. |
| */ |
| |
| if (GOOD_SIGNO(rtcb->sigunbinfo->si_signo)) |
| { |
| /* We were awakened by a signal... but is it one of the signals |
| * that we were waiting for? |
| */ |
| |
| if (nxsig_ismember(set, rtcb->sigunbinfo->si_signo)) |
| { |
| /* Yes.. the return value is the number of the signal that |
| * awakened us. |
| */ |
| |
| ret = rtcb->sigunbinfo->si_signo; |
| } |
| else |
| { |
| /* No... then report the EINTR error */ |
| |
| ret = -EINTR; |
| } |
| } |
| else |
| { |
| /* Otherwise, we must have been awakened by the timeout or, |
| * perhaps, the wait was cancelled. |
| */ |
| |
| #ifdef CONFIG_CANCELLATION_POINTS |
| if (rtcb->sigunbinfo->si_signo == SIG_CANCEL_TIMEOUT) |
| { |
| /* The wait was canceled */ |
| |
| ret = -rtcb->sigunbinfo->si_errno; |
| DEBUGASSERT(ret < 0); |
| } |
| else |
| #endif |
| { |
| /* We were awakened by a timeout. Set EAGAIN and return an |
| * error. |
| */ |
| |
| DEBUGASSERT(rtcb->sigunbinfo->si_signo == SIG_WAIT_TIMEOUT); |
| ret = -EAGAIN; |
| } |
| } |
| |
| rtcb->sigunbinfo = NULL; |
| |
| leave_critical_section(flags); |
| } |
| |
| return ret; |
| } |
| |
| /**************************************************************************** |
| * Name: sigtimedwait |
| * |
| * Description: |
| * This function selects the pending signal set specified by the argument |
| * set. If multiple signals are pending in set, it will remove and return |
| * the lowest numbered one. If no signals in set are pending at the time |
| * of the call, the calling process will be suspended until one of the |
| * signals in set becomes pending, OR until the process is interrupted by |
| * an unblocked signal, OR until the time interval specified by timeout |
| * (if any), has expired. If timeout is NULL, then the timeout interval |
| * is forever. |
| * |
| * If the info argument is non-NULL, the selected signal number is stored |
| * in the si_signo member and the cause of the signal is stored in the |
| * si_code member. The content of si_value is only meaningful if the |
| * signal was generated by sigqueue(). |
| * |
| * The following values for si_code are defined in signal.h: |
| * SI_USER - Signal sent from kill, raise, or abort |
| * SI_QUEUE - Signal sent from sigqueue |
| * SI_TIMER - Signal is result of timer expiration |
| * SI_ASYNCIO - Signal is the result of asynch IO completion |
| * SI_MESGQ - Signal generated by arrival of a message on an |
| * empty message queue. |
| * |
| * Input Parameters: |
| * set - The pending signal set. |
| * info - The returned value (may be NULL). |
| * timeout - The amount of time to wait (may be NULL) |
| * |
| * Returned Value: |
| * Signal number that cause the wait to be terminated, otherwise -1 (ERROR) |
| * is returned with errno set to either: |
| * |
| * EAGAIN - No signal specified by set was generated within the specified |
| * timeout period. |
| * EINTR - The wait was interrupted by an unblocked, caught signal. |
| * |
| ****************************************************************************/ |
| |
| int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *info, |
| FAR const struct timespec *timeout) |
| { |
| int ret; |
| |
| /* sigtimedwait() is a cancellation point */ |
| |
| enter_cancellation_point(); |
| |
| /* Let nxsig_timedwait() do the work. */ |
| |
| ret = nxsig_timedwait(set, info, timeout); |
| if (ret < 0) |
| { |
| set_errno(-ret); |
| ret = ERROR; |
| } |
| |
| leave_cancellation_point(); |
| return ret; |
| } |
