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- /****************************************************************************
- * sched/signal/sig_ppoll.c
- *
- * Copyright (C) 2018 Pinecone Inc. All rights reserved.
- * Author: Xiang Xiao <xiaoxiang@pinecone.net>
- *
- * 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 <poll.h>
- #include "sched/sched.h"
- #include "signal/signal.h"
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: ppoll
- *
- * Description:
- * ppoll() waits for one of a set of file descriptors to become ready to
- * perform I/O. If none of the events requested (and no error) has
- * occurred for any of the file descriptors, then ppoll() blocks until
- * one of the events occurs.
- *
- * Input Parameters:
- * fds - List of structures describing file descriptors to be monitored
- * nfds - The number of entries in the list
- * timeout - Specifies an upper limit on the time for which ppoll() will
- * block. A NULL pointer means an infinite timeout.
- * sigmask - Replace the current signal mask temporarily during execution
- *
- * Returned Value:
- * On success, the number of structures that have non-zero revents fields.
- * A value of 0 indicates that the call timed out and no file descriptors
- * were ready. On error, -1 is returned, and errno is set appropriately:
- *
- * EBADF - An invalid file descriptor was given in one of the sets.
- * EFAULT - The fds address is invalid
- * EINTR - A signal occurred before any requested event.
- * EINVAL - The nfds value exceeds a system limit.
- * ENOMEM - There was no space to allocate internal data structures.
- * ENOSYS - One or more of the drivers supporting the file descriptor
- * does not support the poll method.
- *
- ****************************************************************************/
- int ppoll(FAR struct pollfd *fds, nfds_t nfds,
- FAR const struct timespec *timeout_ts,
- FAR const sigset_t *sigmask)
- {
- FAR struct tcb_s *rtcb = this_task();
- sigset_t saved_sigprocmask;
- irqstate_t flags;
- int ret = ERROR;
- /* 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();
- /* Save a copy of the old sigprocmask and install
- * the new (temporary) sigprocmask
- */
- saved_sigprocmask = rtcb->sigprocmask;
- if (sigmask)
- {
- rtcb->sigprocmask = *sigmask;
- }
- rtcb->sigwaitmask = NULL_SIGNAL_SET;
- /* Check if there is a pending signal corresponding to one of the
- * signals that will be unblocked by the new sigprocmask.
- */
- if (nxsig_unmask_pendingsignal())
- {
- /* Dispatching one or more of the signals is sufficient to cause
- * us to not wait. Restore the original sigprocmask.
- */
- rtcb->sigprocmask = saved_sigprocmask;
- leave_critical_section(flags);
- set_errno(EINTR);
- }
- else
- {
- int timeout = -1;
- /* And call poll to do the real work */
- if (timeout_ts)
- {
- timeout = timeout_ts->tv_sec * 1000 + timeout_ts->tv_nsec / 1000000;
- }
- ret = poll(fds, nfds, timeout);
- /* We are running again, restore the original sigprocmask */
- rtcb->sigprocmask = saved_sigprocmask;
- leave_critical_section(flags);
- /* Now, handle the (rare?) case where (a) a blocked signal was received
- * while the task was suspended but (b) restoring the original
- * sigprocmask will unblock the signal.
- */
- nxsig_unmask_pendingsignal();
- }
- return ret;
- }
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