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355 lines
12 KiB
355 lines
12 KiB
/**************************************************************************** |
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* sched/sig_timedwait.c |
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* |
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* Copyright (C) 2007-2009, 2012 Gregory Nutt. All rights reserved. |
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* Author: Gregory Nutt <gnutt@nuttx.org> |
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* |
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* Redistribution and use in source and binary forms, with or without |
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* modification, are permitted provided that the following conditions |
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* are met: |
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* |
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* 1. Redistributions of source code must retain the above copyright |
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* notice, this list of conditions and the following disclaimer. |
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* 2. Redistributions in binary form must reproduce the above copyright |
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* notice, this list of conditions and the following disclaimer in |
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* the documentation and/or other materials provided with the |
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* distribution. |
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* 3. Neither the name NuttX nor the names of its contributors may be |
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* used to endorse or promote products derived from this software |
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* without specific prior written permission. |
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* |
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS |
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE |
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, |
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, |
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS |
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED |
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN |
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
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* POSSIBILITY OF SUCH DAMAGE. |
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* |
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****************************************************************************/ |
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/**************************************************************************** |
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* Included Files |
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****************************************************************************/ |
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#include <nuttx/config.h> |
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#include <nuttx/compiler.h> |
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#include <stdint.h> |
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#include <string.h> |
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#include <signal.h> |
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#include <time.h> |
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#include <wdog.h> |
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#include <assert.h> |
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#include <debug.h> |
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#include <sched.h> |
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#include <errno.h> |
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#include <nuttx/arch.h> |
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#include "os_internal.h" |
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#include "sig_internal.h" |
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#include "clock_internal.h" |
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/**************************************************************************** |
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* Pre-processor Definitions |
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****************************************************************************/ |
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/* This is a special value of si_signo that means that it was the timeout |
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* that awakened the wait... not the receipt of a signal. |
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*/ |
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#define SIG_WAIT_TIMEOUT 0xff |
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/**************************************************************************** |
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* Private Type Declarations |
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****************************************************************************/ |
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/**************************************************************************** |
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* Global Variables |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Variables |
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****************************************************************************/ |
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/**************************************************************************** |
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* Private Functionss |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: sig_timeout |
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* |
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* Description: |
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* A timeout elapsed while waiting for signals to be queued. |
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* |
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****************************************************************************/ |
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static void sig_timeout(int argc, uint32_t itcb) |
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{ |
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/* On many small machines, pointers are encoded and cannot be simply cast |
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* from uint32_t to _TCB*. The following union works around this |
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* (see wdogparm_t). This odd logic could be conditioned on |
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* CONFIG_CAN_CAST_POINTERS, but it is not too bad in any case. |
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*/ |
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union |
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{ |
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FAR _TCB *wtcb; |
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uint32_t itcb; |
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} u; |
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u.itcb = itcb; |
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if (!u.wtcb) |
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{ |
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PANIC(OSERR_TIMEOUTNOTCB); |
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} |
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/* There may be a race condition -- make sure the task is |
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* still waiting for a signal |
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*/ |
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if (u.wtcb->task_state == TSTATE_WAIT_SIG) |
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{ |
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u.wtcb->sigunbinfo.si_signo = SIG_WAIT_TIMEOUT; |
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u.wtcb->sigunbinfo.si_code = SI_TIMER; |
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u.wtcb->sigunbinfo.si_value.sival_int = 0; |
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#ifdef CONFIG_SCHED_HAVE_PARENT |
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u.wtcb->sigunbinfo.si_pid = 0; /* Not applicable */ |
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u.wtcb->sigunbinfo.si_status = OK; |
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#endif |
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up_unblock_task(u.wtcb); |
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} |
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} |
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/**************************************************************************** |
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* Public Functions |
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****************************************************************************/ |
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/**************************************************************************** |
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* Name: sigtimedwait |
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* |
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* Description: |
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* This function selects the pending signal set specified by the argument |
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* set. If multiple signals are pending in set, it will remove and return |
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* the lowest numbered one. If no signals in set are pending at the time |
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* of the call, the calling process will be suspended until one of the |
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* signals in set becomes pending, OR until the process is interrupted by |
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* an unblocked signal, OR until the time interval specified by timeout |
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* (if any), has expired. If timeout is NULL, then the timeout interval |
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* is forever. |
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* |
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* If the info argument is non-NULL, the selected signal number is stored |
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* in the si_signo member and the cause of the signal is store in the |
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* si_code emember. The content of si_value is only meaningful if the |
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* signal was generated by sigqueue(). |
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* |
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* The following values for si_code are defined in signal.h: |
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* SI_USER - Signal sent from kill, raise, or abort |
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* SI_QUEUE - Signal sent from sigqueue |
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* SI_TIMER - Signal is result of timer expiration |
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* SI_ASYNCIO - Signal is the result of asynch IO completion |
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* SI_MESGQ - Signal generated by arrival of a message on an |
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* empty message queue. |
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* |
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* Parameters: |
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* set - The pending signal set. |
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* info - The returned value |
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* timeout - The amount of time to wait |
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* |
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* Return Value: |
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* Signal number that cause the wait to be terminated, otherwise -1 (ERROR) |
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* is returned with errno set to either: |
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* |
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* EAGAIN - No signal specified by set was generated within the specified |
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* timeout period. |
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* EINTR - The wait was interrupted by an unblocked, caught signal. |
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* |
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* Assumptions: |
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* |
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****************************************************************************/ |
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int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *info, |
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FAR const struct timespec *timeout) |
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{ |
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FAR _TCB *rtcb = (FAR _TCB*)g_readytorun.head; |
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sigset_t intersection; |
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FAR sigpendq_t *sigpend; |
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WDOG_ID wdog; |
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irqstate_t saved_state; |
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int32_t waitticks; |
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int ret = ERROR; |
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sched_lock(); /* Not necessary */ |
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/* Several operations must be performed below: We must determine if any |
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* signal is pending and, if not, wait for the signal. Since signals can |
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* be posted from the interrupt level, there is a race condition that |
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* can only be eliminated by disabling interrupts! |
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*/ |
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saved_state = irqsave(); |
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/* Check if there is a pending signal corresponding to one of the |
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* signals in the pending signal set argument. |
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*/ |
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intersection = *set & sig_pendingset(rtcb); |
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if (intersection != NULL_SIGNAL_SET) |
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{ |
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/* One or more of the signals in intersections is sufficient to cause |
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* us to not wait. Pick the lowest numbered signal and mark it not |
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* pending. |
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*/ |
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sigpend = sig_removependingsignal(rtcb, sig_lowest(&intersection)); |
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if (!sigpend) |
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{ |
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PANIC(OSERR_NOPENDINGSIGNAL); |
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} |
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/* Return the signal info to the caller if so requested */ |
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if (info) |
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{ |
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memcpy(info, &sigpend->info, sizeof(struct siginfo)); |
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} |
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/* Then dispose of the pending signal structure properly */ |
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sig_releasependingsignal(sigpend); |
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irqrestore(saved_state); |
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/* The return value is the number of the signal that awakened us */ |
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ret = sigpend->info.si_signo; |
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} |
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/* We will have to wait for a signal to be posted to this task. */ |
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else |
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{ |
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/* Save the set of pending signals to wait for */ |
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rtcb->sigwaitmask = *set; |
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/* Check if we should wait for the timeout */ |
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if (timeout) |
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{ |
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/* Convert the timespec to system clock ticks, making sure that |
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* the resultint delay is greater than or equal to the requested |
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* time in nanoseconds. |
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*/ |
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#ifdef CONFIG_HAVE_LONG_LONG |
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uint64_t waitticks64 = ((uint64_t)timeout->tv_sec * NSEC_PER_SEC + |
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(uint64_t)timeout->tv_nsec + NSEC_PER_TICK - 1) / |
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NSEC_PER_TICK; |
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DEBUGASSERT(waitticks64 <= UINT32_MAX); |
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waitticks = (uint32_t)waitticks64; |
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#else |
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uint32_t waitmsec; |
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DEBUGASSERT(timeout->tv_sec < UINT32_MAX / MSEC_PER_SEC); |
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waitmsec = timeout->tv_sec * MSEC_PER_SEC + |
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(timeout->tv_nsec + NSEC_PER_MSEC - 1) / NSEC_PER_MSEC; |
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waitticks = (waitmsec + MSEC_PER_TICK - 1) / MSEC_PER_TICK; |
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#endif |
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/* Create a watchdog */ |
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wdog = wd_create(); |
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if (wdog) |
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{ |
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/* This little of nonsense is necessary for some |
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* processors where sizeof(pointer) < sizeof(uint32_t). |
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* see wdog.h. |
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*/ |
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wdparm_t wdparm; |
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wdparm.pvarg = (FAR void*)rtcb; |
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/* Start the watchdog */ |
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wd_start(wdog, waitticks, (wdentry_t)sig_timeout, 1, wdparm.dwarg); |
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/* Now wait for either the signal or the watchdog */ |
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up_block_task(rtcb, TSTATE_WAIT_SIG); |
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/* We no longer need the watchdog */ |
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wd_delete(wdog); |
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} |
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} |
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/* No timeout, just wait */ |
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else |
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{ |
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/* And wait until one of the unblocked signals is posted */ |
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up_block_task(rtcb, TSTATE_WAIT_SIG); |
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} |
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/* We are running again, clear the sigwaitmask */ |
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rtcb->sigwaitmask = NULL_SIGNAL_SET; |
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/* When we awaken, the cause will be in the TCB. Get the signal number |
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* or timeout) that awakened us. |
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*/ |
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if (GOOD_SIGNO(rtcb->sigunbinfo.si_signo)) |
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{ |
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/* We were awakened by a signal... but is it one of the signals that |
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* we were waiting for? |
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*/ |
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if (sigismember(set, rtcb->sigunbinfo.si_signo)) |
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{ |
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/* Yes.. the return value is the number of the signal that |
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* awakened us. |
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*/ |
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ret = rtcb->sigunbinfo.si_signo; |
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} |
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else |
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{ |
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/* No... then set EINTR and report an error */ |
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set_errno(EINTR); |
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ret = ERROR; |
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} |
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} |
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else |
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{ |
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/* Otherwise, we must have been awakened by the timeout. Set EGAIN |
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* and return an error. |
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*/ |
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DEBUGASSERT(rtcb->sigunbinfo.si_signo == SIG_WAIT_TIMEOUT); |
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set_errno(EAGAIN); |
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ret = ERROR; |
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} |
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/* Return the signal info to the caller if so requested */ |
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if (info) |
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{ |
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memcpy(info, &rtcb->sigunbinfo, sizeof(struct siginfo)); |
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} |
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irqrestore(saved_state); |
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} |
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sched_unlock(); |
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return ret; |
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}
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