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/****************************************************************************
* sched/sig_deliver.c
*
* Copyright (C) 2007, 2008, 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 <sys/types.h>
#include <signal.h>
#include <unistd.h>
#include <sched.h>
#include <string.h>
#include <debug.h>
#include <nuttx/arch.h>
#include "os_internal.h"
#include "sem_internal.h"
#include "sig_internal.h"
/****************************************************************************
* Definitions
****************************************************************************/
/****************************************************************************
* Private Type Declarations
****************************************************************************/
/****************************************************************************
* Global Variables
****************************************************************************/
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: sig_deliver
*
* Description:
* This function is called on the thread of execution of the signal
* receiving task. It processes all queued signals then returns.
*
****************************************************************************/
void sig_deliver(FAR struct tcb_s *stcb)
{
FAR sigq_t *sigq;
FAR sigq_t *next;
sigset_t savesigprocmask;
irqstate_t saved_state;
int saved_errno;
sched_lock();
/* Save the thread errno. When we finished dispatching the
* signal actions and resume the task, the errno value must
* be unchanged by the operation of the signal handling. In
* particular, the EINTR indication that says that the task
* was reawakened by a signal must be retained.
*/
saved_errno = stcb->pterrno;
for (sigq = (FAR sigq_t*)stcb->sigpendactionq.head; (sigq); sigq = next)
{
next = sigq->flink;
sdbg("Sending signal sigq=0x%x\n", sigq);
/* Remove the signal structure from the sigpendactionq and place it
* in the sigpostedq. NOTE: Since signals are processed one at a
* time, there should never be more than one signal in the sigpostedq
*/
saved_state = irqsave();
sq_rem((FAR sq_entry_t*)sigq, &(stcb->sigpendactionq));
sq_addlast((FAR sq_entry_t*)sigq, &(stcb->sigpostedq));
irqrestore(saved_state);
/* Call the signal handler (unless the signal was cancelled)
*
* Save a copy of the old sigprocmask and install the new
* (temporary) sigprocmask. The new sigprocmask is the union
* of the current sigprocmask and the sa_mask for the signal being
* delivered plus the signal being delivered.
*/
savesigprocmask = stcb->sigprocmask;
stcb->sigprocmask = savesigprocmask | sigq->mask | SIGNO2SET(sigq->info.si_signo);
/* Deliver the signal. In the kernel build this has to be handled
* differently if we are dispatching to a signal handler in a user-
* space task or thread; we have to switch to user-mode before
* calling the task.
*/
#ifdef CONFIG_NUTTX_KERNEL
if ((stcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
{
/* The sigq_t pointed to by sigq resides in kernel space. So we
* cannot pass a reference to sigq->info to the user application.
* Instead, we will copy the siginfo_t structure onto the stack.
* We are currently executing on the stack of the user thread
* (albeit temporarily in kernel mode), so the copy of the
* siginfo_t structure will be accessible by the user thread.
*/
siginfo_t info;
memcpy(&info, &sigq->info, sizeof(siginfo_t));
up_signal_dispatch(sigq->action.sighandler, sigq->info.si_signo,
&info, NULL);
}
else
#endif
{
/* The kernel thread signal handler is much simpler. */
(*sigq->action.sighandler)(sigq->info.si_signo, &sigq->info,
NULL);
}
/* Restore the original sigprocmask */
stcb->sigprocmask = savesigprocmask;
/* Now, handle the (rare?) case where (a) a blocked signal was
* received while the signal handling executed but (b) restoring the
* original sigprocmask will unblock the signal.
*/
sig_unmaskpendingsignal();
/* Remove the signal from the sigpostedq */
saved_state = irqsave();
sq_rem((FAR sq_entry_t*)sigq, &(stcb->sigpostedq));
irqrestore(saved_state);
/* Then deallocate it */
sig_releasependingsigaction(sigq);
}
stcb->pterrno = saved_errno;
sched_unlock();
}
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