111 lines
4.7 KiB
C
111 lines
4.7 KiB
C
/****************************************************************************
|
|
* libs/libc/signal/sig_wait.c
|
|
*
|
|
* Copyright (C) 2017 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 <signal.h>
|
|
#include <assert.h>
|
|
#include <errno.h>
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: sigwait
|
|
*
|
|
* Description:
|
|
* The sigwait() function selects a pending signal from set, atomically
|
|
* clears it from the system's set of pending signals, and returns that
|
|
* signal number in the location referenced by sig. If prior to the call
|
|
* to sigwait() there are multiple pending instances of a single signal
|
|
* number, it is implementation-dependent whether upon successful return
|
|
* there are any remaining pending signals for that signal number. If the
|
|
* implementation supports queued signals and there are multiple signals
|
|
* queued for the signal number selected, the first such queued signal
|
|
* causes a return from sigwait() and the remainder remain queued. If no
|
|
* signal in set is pending at the time of the call, the thread is
|
|
* suspended until one or more becomes pending. The signals defined by set
|
|
* will been blocked at the time of the call to sigwait(); otherwise the
|
|
* behavior is undefined. The effect of sigwait() on the signal actions
|
|
* for the signals in set is unspecified.
|
|
*
|
|
* If more than one thread is using sigwait() to wait for the same
|
|
* signal, no more than one of these threads will return from sigwait()
|
|
* with the signal number. Which thread returns from sigwait() if more
|
|
* than a single thread is waiting is unspecified.
|
|
*
|
|
* Should any of the multiple pending signals in the range SIGRTMIN to
|
|
* SIGRTMAX be selected, it shall be the lowest numbered one. The selection
|
|
* order between realtime and non-realtime signals, or between multiple
|
|
* pending non-realtime signals, is unspecified.
|
|
*
|
|
* Input Parameters:
|
|
* set - The set of pending signals to wait for
|
|
* sig - The location in which to return the pending signal number.
|
|
*
|
|
* Returned Value:
|
|
* Upon successful completion, sigwait() stores the signal number of the
|
|
* received signal at the location referenced by sig and returns zero.
|
|
* Otherwise, an error number is returned to indicate the error.
|
|
*
|
|
****************************************************************************/
|
|
|
|
int sigwait(FAR const sigset_t *set, FAR int *sig)
|
|
{
|
|
int signo;
|
|
|
|
DEBUGASSERT(set != NULL && sig != NULL);
|
|
|
|
/* The standard sigwait() function behaves that same as sigwaitinfo() with
|
|
* the info argument set to NULL.
|
|
*/
|
|
|
|
signo = sigwaitinfo(set, NULL);
|
|
if (signo < 0)
|
|
{
|
|
/* If sigwaitinfo() fails, return the error number */
|
|
|
|
return get_errno();
|
|
}
|
|
|
|
/* Return the signal number in the user provided location */
|
|
|
|
*sig = signo;
|
|
return OK;
|
|
}
|