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libc/signal: Add support for sigwait().

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This commit is contained in:
Gregory Nutt 2017-11-11 12:37:47 -06:00
parent 5004e8b3ea
commit bf7839d0f0
4 changed files with 123 additions and 20 deletions
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26
TODO
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@ -557,36 +557,28 @@ o pthreads (sched/pthreads)
exceptions as noted:
accept() mq_timedsend() NA putpmsg() sigtimedwait()
04 aio_suspend() NA msgrcv() pwrite() NA sigwait()
aio_suspend() NA msgrcv() pwrite() sigwait()
NA clock_nanosleep() NA msgsnd() read() sigwaitinfo()
close() NA msync() NA readv() 01 sleep()
connect() nanosleep() recv() 02 system()
close() NA msync() readv() sleep()
connect() nanosleep() recv() 01 system()
-- creat() open() recvfrom() tcdrain()
fcntl() pause() NA recvmsg() 01 usleep()
fcntl() pause() NA recvmsg() usleep()
NA fdatasync() poll() select() -- wait()
fsync() pread() sem_timedwait() waitid()
NA getmsg() NA pselect() sem_wait() waitpid()
NA getpmsg() pthread_cond_timedwait() send() write()
NA lockf() pthread_cond_wait() NA sendmsg() NA writev()
NA lockf() pthread_cond_wait() NA sendmsg() writev()
mq_receive() pthread_join() sendto()
mq_send() pthread_testcancel() 03 sigpause()
mq_send() pthread_testcancel() sigpause()
mq_timedreceive() NA putmsg() sigsuspend()
NA Not supported
-- Doesn't need instrumentation. Handled by lower level calls.
nn See note nn
NOTE 01: sleep() and usleep() are user-space functions in the C library and cannot
serve as cancellation points. They are, however, simple wrappers around nanosleep
which is a true cancellation point.
NOTE 02: system() is actually implemented in apps/ as part of NSH. It cannot be
a cancellation point.
NOTE 03: sigpause() is a user-space function in the C library and cannot serve as
cancellation points. It is, however, a simple wrapper around sigsuspend()
which is a true cancellation point.
NOTE 04: aio_suspend() is a user-space function in the C library and cannot serve as
cancellation points. It does call around sigtimedwait() which is a true cancellation
point.
NOTE 01: system() is actually implemented in apps/ as part of NSH. It cannot be
a cancellation point but probably will cause a cancellation due to lower level
system calls.
Status: Not really open. This is just the way it is.
Priority: Nothing additional is planned.

3
include/signal.h
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@ -1,7 +1,7 @@
/********************************************************************************
* include/signal.h
*
* Copyright (C) 2007-2009, 2011, 2013-2016 Gregory Nutt. All rights reserved.
* Copyright (C) 2007-2009, 2011, 2013-2017 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <gnutt@nuttx.org>
*
* Redistribution and use in source and binary forms, with or without
@ -308,6 +308,7 @@ int sigqueue(int pid, int signo, FAR void *sival_ptr);
#endif
int sigrelse(int signo);
_sa_handler_t sigset(int signo, _sa_handler_t func);
int sigwait(FAR const sigset_t *set, FAR int *sig);
int sigtimedwait(FAR const sigset_t *set, FAR struct siginfo *value,
FAR const struct timespec *timeout);
int sigsuspend(FAR const sigset_t *sigmask);

4
libc/signal/Make.defs
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@ -1,7 +1,7 @@
############################################################################
# libc/signal/Make.defs
#
# Copyright (C) 2011-2012, 2016 Gregory Nutt. All rights reserved.
# Copyright (C) 2011-2012, 2016-2017 Gregory Nutt. All rights reserved.
# Author: Gregory Nutt <gnutt@nuttx.org>
#
# Redistribution and use in source and binary forms, with or without
@ -39,7 +39,7 @@ ifneq ($(CONFIG_DISABLE_SIGNALS),y)
CSRCS += sig_addset.c sig_delset.c sig_emptyset.c sig_fillset.c
CSRCS += sig_hold.c sig_ignore.c sig_ismember.c sig_pause.c sig_raise.c
CSRCS += sig_relse.c sig_set.c signal.c
CSRCS += sig_relse.c sig_set.c signal.c sigwait.c
# Add the signal directory to the build

110
libc/signal/sigwait.c Normal file
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@ -0,0 +1,110 @@
/****************************************************************************
* libc/signal/sigwait.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 sigwainfo() 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;
}