| /**************************************************************************** |
| * sched/sig_timedwait.c |
| * |
| * Copyright (C) 2007-2009, 2012-2013 Gregory Nutt. All rights reserved. |
| * Author: Gregory Nutt <gnutt@nuttx.org> |
| * |
| * 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 NuttX 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 <nuttx/config.h> |
| #include <nuttx/compiler.h> |
| |
| #include <stdint.h> |
| #include <string.h> |
| #include <signal.h> |
| #include <time.h> |
| #include <wdog.h> |
| #include <assert.h> |
| #include <debug.h> |
| #include <sched.h> |
| #include <errno.h> |
| |
| #include <nuttx/arch.h> |
| |
| #include "os_internal.h" |
| #include "sig_internal.h" |
| #include "clock_internal.h" |
| |
| /**************************************************************************** |
| * Pre-processor Definitions |
| ****************************************************************************/ |
| |
| /* This is a special value of si_signo that means that it was the timeout |
| * that awakened the wait... not the receipt of a signal. |
| */ |
| |
| #define SIG_WAIT_TIMEOUT 0xff |
| |
| /**************************************************************************** |
| * Private Type Declarations |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Global Variables |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Private Variables |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Private Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * Name: sig_timeout |
| * |
| * Description: |
| * A timeout elapsed while waiting for signals to be queued. |
| * |
| ****************************************************************************/ |
| |
| static void sig_timeout(int argc, uint32_t itcb) |
| { |
| /* On many small machines, pointers are encoded and cannot be simply cast |
| * from uint32_t to struct tcb_s*. The following union works around this |
| * (see wdogparm_t). This odd logic could be conditioned on |
| * CONFIG_CAN_CAST_POINTERS, but it is not too bad in any case. |
| */ |
| |
| union |
| { |
| FAR struct tcb_s *wtcb; |
| uint32_t itcb; |
| } u; |
| |
| u.itcb = itcb; |
| ASSERT(u.wtcb); |
| |
| /* There may be a race condition -- make sure the task is |
| * still waiting for a signal |
| */ |
| |
| if (u.wtcb->task_state == TSTATE_WAIT_SIG) |
| { |
| u.wtcb->sigunbinfo.si_signo = SIG_WAIT_TIMEOUT; |
| u.wtcb->sigunbinfo.si_code = SI_TIMER; |
| u.wtcb->sigunbinfo.si_value.sival_int = 0; |
| #ifdef CONFIG_SCHED_HAVE_PARENT |
| u.wtcb->sigunbinfo.si_pid = 0; /* Not applicable */ |
| u.wtcb->sigunbinfo.si_status = OK; |
| #endif |
| up_unblock_task(u.wtcb); |
| } |
| } |
| |
| /**************************************************************************** |
| * Public Functions |
| ****************************************************************************/ |
| |
| /**************************************************************************** |
| * 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 store din 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. |
| * |
| * Parameters: |
| * set - The pending signal set. |
| * info - The returned value |
| * timeout - The amount of time to wait |
| * |
| * Return 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. |
| * |
| * Assumptions: |
| * |
| ****************************************************************************/ |
| |
| int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *info, |
| FAR const struct timespec *timeout) |
| { |
| FAR struct tcb_s *rtcb = (FAR struct tcb_s*)g_readytorun.head; |
| sigset_t intersection; |
| FAR sigpendq_t *sigpend; |
| irqstate_t saved_state; |
| int32_t waitticks; |
| int ret = ERROR; |
| |
| DEBUGASSERT(rtcb->waitdog == NULL); |
| |
| sched_lock(); /* Not necessary */ |
| |
| /* 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! |
| */ |
| |
| saved_state = irqsave(); |
| |
| /* Check if there is a pending signal corresponding to one of the |
| * signals in the pending signal set argument. |
| */ |
| |
| intersection = *set & sig_pendingset(rtcb); |
| if (intersection != NULL_SIGNAL_SET) |
| { |
| /* 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 = sig_removependingsignal(rtcb, sig_lowest(&intersection)); |
| ASSERT(sigpend); |
| |
| /* Return the signal info to the caller if so requested */ |
| |
| if (info) |
| { |
| memcpy(info, &sigpend->info, sizeof(struct siginfo)); |
| } |
| |
| /* Then dispose of the pending signal structure properly */ |
| |
| sig_releasependingsignal(sigpend); |
| irqrestore(saved_state); |
| |
| /* The return value is the number of the signal that awakened us */ |
| |
| ret = sigpend->info.si_signo; |
| } |
| |
| /* We will have to wait for a signal to be posted to this task. */ |
| |
| else |
| { |
| /* Save the set of pending signals to wait for */ |
| |
| rtcb->sigwaitmask = *set; |
| |
| /* Check if we should wait for the timeout */ |
| |
| if (timeout) |
| { |
| /* 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_HAVE_LONG_LONG |
| uint64_t waitticks64 = ((uint64_t)timeout->tv_sec * NSEC_PER_SEC + |
| (uint64_t)timeout->tv_nsec + NSEC_PER_TICK - 1) / |
| NSEC_PER_TICK; |
| DEBUGASSERT(waitticks64 <= UINT32_MAX); |
| waitticks = (uint32_t)waitticks64; |
| #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 = (waitmsec + MSEC_PER_TICK - 1) / MSEC_PER_TICK; |
| #endif |
| |
| /* Create a watchdog */ |
| |
| rtcb->waitdog = wd_create(); |
| DEBUGASSERT(rtcb->waitdog); |
| |
| if (rtcb->waitdog) |
| { |
| /* This little bit of nonsense is necessary for some |
| * processors where sizeof(pointer) < sizeof(uint32_t). |
| * see wdog.h. |
| */ |
| |
| wdparm_t wdparm; |
| wdparm.pvarg = (FAR void *)rtcb; |
| |
| /* Start the watchdog */ |
| |
| wd_start(rtcb->waitdog, waitticks, (wdentry_t)sig_timeout, 1, |
| wdparm.dwarg); |
| |
| /* Now wait for either the signal or the watchdog */ |
| |
| up_block_task(rtcb, TSTATE_WAIT_SIG); |
| |
| /* We no longer need the watchdog */ |
| |
| wd_delete(rtcb->waitdog); |
| rtcb->waitdog = NULL; |
| } |
| |
| /* REVISIT: And do what if there are no watchdog timers? The wait |
| * will fail and we will return something bogus. |
| */ |
| } |
| |
| /* No timeout, just wait */ |
| |
| else |
| { |
| /* And wait until one of the unblocked signals is posted */ |
| |
| up_block_task(rtcb, TSTATE_WAIT_SIG); |
| } |
| |
| /* We are running again, clear the sigwaitmask */ |
| |
| rtcb->sigwaitmask = NULL_SIGNAL_SET; |
| |
| /* 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 (sigismember(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 set EINTR and report an error */ |
| |
| set_errno(EINTR); |
| ret = ERROR; |
| } |
| } |
| else |
| { |
| /* Otherwise, we must have been awakened by the timeout. Set EGAIN |
| * and return an error. |
| */ |
| |
| DEBUGASSERT(rtcb->sigunbinfo.si_signo == SIG_WAIT_TIMEOUT); |
| set_errno(EAGAIN); |
| ret = ERROR; |
| } |
| |
| /* Return the signal info to the caller if so requested */ |
| |
| if (info) |
| { |
| memcpy(info, &rtcb->sigunbinfo, sizeof(struct siginfo)); |
| } |
| |
| irqrestore(saved_state); |
| } |
| |
| sched_unlock(); |
| return ret; |
| } |
