nuttx/sched/signal/sig_deliver.c

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/****************************************************************************
* sched/signal/sig_deliver.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* 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/irq.h>
#include <nuttx/arch.h>
#include "signal/signal.h"
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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* Name: nxsig_deliver
*
* Description:
* This function is called on the thread of execution of the signal
* receiving task. It processes all queued signals then returns.
*
****************************************************************************/
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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void nxsig_deliver(FAR struct tcb_s *stcb)
{
/* Save the errno. This must be preserved throughout the signal handling
* so that the user code final gets the correct errno value (probably
* EINTR).
*/
int saved_errno = get_errno();
int16_t saved_errcode = stcb->errcode;
FAR sigq_t *sigq;
sigset_t savesigprocmask;
sigset_t newsigprocmask;
sigset_t altsigprocmask;
irqstate_t flags;
/* Loop while there are signals to be delivered */
for (; ; )
{
/* Test if this task is already handling a signal (we don't permit
* nested signals on the same thread).
*/
flags = enter_critical_section();
if ((stcb->flags & TCB_FLAG_SIGNAL_ACTION) != 0)
{
/* Yes.. then we must wait for the signal handler to return */
leave_critical_section(flags);
break;
}
/* Remove the signal structure from the head of the sigpendactionq. */
sigq = (FAR sigq_t *)sq_remfirst(&stcb->sigpendactionq);
if (sigq == NULL)
{
/* All queued signal actions have been dispatched */
leave_critical_section(flags);
break;
}
/* Indicate that a signal is being delivered */
stcb->flags |= TCB_FLAG_SIGNAL_ACTION;
sinfo("Deliver signal %d to PID %d\n",
sigq->info.si_signo, stcb->pid);
/* Add the signal structure to the sigpostedq. NOTE: Since signals
* are processed one at a time, there should never be more than one
* signal in the sigpostedq
*/
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sq_addlast((FAR sq_entry_t *)sigq, &(stcb->sigpostedq));
/* 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.
*/
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savesigprocmask = stcb->sigprocmask;
newsigprocmask = savesigprocmask | sigq->mask;
stcb->sigprocmask = newsigprocmask;
#ifndef CONFIG_BUILD_FLAT
/* 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_SIG_DEFAULT
/* The default signal action handlers, however always reside in the
* kernel address space, regardless of configuration.
*/
if (nxsig_isdefault(stcb, sigq->info.si_signo))
{
/* Leave the critical section before calling the handler */
leave_critical_section(flags);
(*sigq->action.sighandler)(sigq->info.si_signo, &sigq->info,
NULL);
}
else
#endif
if ((stcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_KERNEL)
{
siginfo_t info;
/* 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.
*/
memcpy(&info, &sigq->info, sizeof(siginfo_t));
/* Leave the critical section before calling the handler */
leave_critical_section(flags);
up_signal_dispatch(sigq->action.sighandler, sigq->info.si_signo,
&info, NULL);
}
else
#endif
{
/* The kernel thread signal handler is much simpler. */
leave_critical_section(flags);
(*sigq->action.sighandler)(sigq->info.si_signo, &sigq->info,
NULL);
}
/* Indicate that a signal has been delivered */
flags = enter_critical_section();
stcb->flags &= ~TCB_FLAG_SIGNAL_ACTION;
/* Restore the original sigprocmask.
*
* What if the signal handler changed the sigprocmask? Try to retain
* any such changes here.
*
* REVISIT: This logic is imperfect. It will fail to detect bits set
* in the current sigprocmask that were already set by newsigprocmask.
*/
altsigprocmask = stcb->sigprocmask ^ newsigprocmask;
stcb->sigprocmask = (stcb->sigprocmask & altsigprocmask) |
(savesigprocmask & ~altsigprocmask);
/* Remove the signal structure from the sigpostedq */
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sq_rem((FAR sq_entry_t *)sigq, &(stcb->sigpostedq));
leave_critical_section(flags);
/* 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.
*/
nxsig_unmask_pendingsignal();
/* Then deallocate the signal structure */
This change renames all internal, private NuttX signal-related functions to use the prefix nxsig_ so that they cannot be confused with application interfaces that begin, primarily, with sig_ This is analogous to similar renaming that was done previously for semaphores. Squashed commit of the following: sched/signal: Fix a few compile warnings introduced by naming changes. sched/signal: Rename all private, internal signl functions to use the nxsig_ prefix. sched/signal: Rename sig_removependingsignal, sig_unmaskpendingsignal, and sig_mqnotempty to nxsig_remove_pendingsignal, nxsig_unmask_pendingsignal, and nxsig_mqnotempty to make it clear that these are OS internal interfaces. sched/signal: Rename sig_findaction and sig_lowest to nxsig_find_action and nxsig_lowest to make it clear that these are OS internal interfaces. sched/signal: Rename sig_allocatepingsigaction and sig_deliver to nxsig_alloc_pendingsigaction and nxsig_deliver to make it clear that these are OS internal interfaces. sched/signal: Rename sig_cleanup, sig_release, sig_releasependingaction, and sig_releasependingsignal to nxsig_cleanup, nxsig_release, nxsig_release_pendingaction, and nxsig_release_pendingsignal to make it clear that these are OS internal interfaces. sched/signal: Rename sig_tcbdispatch and sig_dispatch to nxsig_tcbdispatch and nxsig_dispatch to make it clear that these are OS internal interfaces. sched/signal: Rename sig_releaseaction and sig_pendingset to nxsig_release_action and nxsig_pendingset to make it clear that these are OS internal interfaces. sched/signal: Rename sig_initialize and sig_allocateactionblock to nxsig_initialize and nxsig_alloc_actionblock to make it clear that these are OS internal interfaces.
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nxsig_release_pendingsigaction(sigq);
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}
/* Restore the saved errno value */
set_errno(saved_errno);
stcb->errcode = saved_errcode;
}