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- /****************************************************************************
- * sched/signal/sig_default.c
- *
- * Copyright (C) 2018 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/wait.h>
- #include <stdint.h>
- #include <stdlib.h>
- #include <string.h>
- #include <pthread.h>
- #include <signal.h>
- #include <assert.h>
- #include <nuttx/sched.h>
- #include <nuttx/irq.h>
- #include <nuttx/signal.h>
- #include "group/group.h"
- #include "sched/sched.h"
- #include "signal/signal.h"
- /****************************************************************************
- * Pre-processor Definitions
- ****************************************************************************/
- /* Bit definitions for the struct nxsig_defaction_s 'flags' field */
- #define SIG_FLAG_NOCATCH (1 << 0) /* Signal cannot be caught or ignored */
- /****************************************************************************
- * Private Types
- ****************************************************************************/
- /* This type provides the default action associated with a signal */
- struct nxsig_defaction_s
- {
- uint8_t signo; /* Signal number. Range 1..MAX_SIGNO */
- uint8_t flags; /* See SIG_FLAG_ definitions */
- _sa_handler_t action; /* Default signal action */
- };
- /****************************************************************************
- * Private Function Prototypes
- ****************************************************************************/
- /* Default actions */
- static void nxsig_null_action(int signo);
- static void nxsig_abnormal_termination(int signo);
- static void nxsig_stop_task(int signo);
- /* Helpers */
- static _sa_handler_t nxsig_default_action(int signo);
- static void nxsig_setup_default_action(FAR struct task_group_s *group,
- FAR const struct nxsig_defaction_s *info);
- /****************************************************************************
- * Private Data
- ****************************************************************************/
- /* NOTE: Default actions are not currently supported for very many signals.
- * However, this array is set up to support an indefinite number of default
- * signal actions.
- */
- /* This table is used to make the default action for a signal to the correct
- * signal handler. Signals whose default action is be ignored do not need
- * to be in this table (e.g., SIGCHLD).
- */
- static const struct nxsig_defaction_s g_defactions[] =
- {
- #ifdef CONFIG_SIG_SIGUSR1_ACTION
- { SIGUSR1, 0, nxsig_abnormal_termination },
- #endif
- #ifdef CONFIG_SIG_SIGUSR2_ACTION
- { SIGUSR2, 0, nxsig_abnormal_termination },
- #endif
- #ifdef CONFIG_SIG_SIGALRM_ACTION
- { SIGALRM, 0, nxsig_abnormal_termination },
- #endif
- #ifdef CONFIG_SIG_SIGPOLL_ACTION
- { SIGPOLL, 0, nxsig_abnormal_termination },
- #endif
- #ifdef CONFIG_SIG_SIGSTOP_ACTION
- { SIGSTOP, SIG_FLAG_NOCATCH, nxsig_stop_task },
- { SIGSTP, 0, nxsig_stop_task },
- { SIGCONT, SIG_FLAG_NOCATCH, nxsig_null_action },
- #endif
- #ifdef CONFIG_SIG_SIGKILL_ACTION
- { SIGINT, 0, nxsig_abnormal_termination },
- { SIGKILL, SIG_FLAG_NOCATCH, nxsig_abnormal_termination }
- #endif
- };
- #define NACTIONS (sizeof(g_defactions) / sizeof(struct nxsig_defaction_s))
- /****************************************************************************
- * Private Functions
- ****************************************************************************/
- /* TODO: Take into account pthread-specific signal behaviors */
- /* Default Actions:
- *
- * - Abnormal termination of the process. The process is terminated with
- * all the consequences of _exit() except that the status made available
- * to wait() and waitpid() indicates abnormal termination by the
- * specified signal.
- * - Abnormal termination of the process. Additionally with the XSI
- * extension, implementation-defined abnormal termination actions, such
- * as creation of a core file, may occur.
- * - Ignore the signal.
- * - Stop the process.
- * - Continue the process, if it is stopped; otherwise, ignore the signal.
- */
- /****************************************************************************
- * Name: nxsig_null_action
- *
- * Description:
- * The do-nothing default signal action handler.
- *
- * Input Parameters:
- * Standard signal handler parameters
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
- static void nxsig_null_action(int signo)
- {
- }
- /****************************************************************************
- * Name: nxsig_abnormal_termination
- *
- * Description:
- * This is the handler for the abnormal termination default action.
- *
- * Input Parameters:
- * Standard signal handler parameters
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
- static void nxsig_abnormal_termination(int signo)
- {
- FAR struct tcb_s *rtcb = (FAR struct tcb_s *)this_task();
- /* Careful: In the multi-threaded task, the signal may be handled on a
- * child pthread.
- */
- #ifdef HAVE_GROUP_MEMBERS
- /* Kill of of the children of the task. This will not kill the currently
- * running task/pthread (this_task). It will kill the main thread of the
- * task group if the this_task is a
- * pthread.
- */
- group_killchildren((FAR struct task_tcb_s *)rtcb);
- #endif
- #ifndef CONFIG_DISABLE_PTHREAD
- /* Check if the currently running task is actually a pthread */
- if ((rtcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_PTHREAD)
- {
- /* Exit the final thread of the task group.
- *
- * REVISIT: This will not work if HAVE_GROUP_MEMBERS is not set.
- */
- pthread_exit(NULL);
- }
- else
- #endif
- {
- /* Exit to terminate the task (note that exit() vs. _exit() is used. */
- exit(EXIT_FAILURE);
- }
- }
- /****************************************************************************
- * Name: nxsig_stop_task
- *
- * Description:
- * This is the handler for the abnormal termination default action.
- *
- * Input Parameters:
- * Standard signal handler parameters
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
- static void nxsig_stop_task(int signo)
- {
- FAR struct tcb_s *rtcb = (FAR struct tcb_s *)this_task();
- #if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
- FAR struct task_group_s *group;
- DEBUGASSERT(rtcb != NULL && rtcb->group != NULL);
- group = rtcb->group;
- #endif
- /* Careful: In the multi-threaded task, the signal may be handled on a
- * child pthread.
- */
- #ifdef HAVE_GROUP_MEMBERS
- /* Suspend of of the children of the task. This will not suspend the
- * currently running task/pthread (this_task). It will suspend the
- * main thread of the task group if the this_task is a pthread.
- */
- group_suspendchildren(rtcb);
- #endif
- /* Lock the scheduler so this thread is not pre-empted until after we
- * call sched_suspend().
- */
- sched_lock();
- #if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
- /* Notify via waitpid if any parent is waiting for this task to EXIT
- * or STOP. This action is only performed if WUNTRACED is set in the
- * waitpid flags.
- */
- if ((group->tg_waitflags & WUNTRACED) != 0)
- {
- /* Return zero for exit status (we are not exiting, however) */
- if (group->tg_statloc != NULL)
- {
- *group->tg_statloc = 0;
- group->tg_statloc = NULL;
- }
- /* tg_waitflags == 0 means that the flags are available to another
- * caller of waitpid().
- */
- group->tg_waitflags = 0;
- /* YWakeup any tasks waiting for this task to exit or stop. */
- while (group->tg_exitsem.semcount < 0)
- {
- /* Wake up the thread */
- nxsem_post(&group->tg_exitsem);
- }
- }
- #endif
- /* Then, finally, suspend this the final thread of the task group */
- sched_suspend(rtcb);
- sched_unlock();
- }
- /****************************************************************************
- * Name: nxsig_default_action
- *
- * Description:
- * Look up the default action associated with this signal
- *
- * Input Parameters:
- * signo - The signal number to use in the query
- *
- * Returned Value:
- * The default handler associated with this signal
- *
- ****************************************************************************/
- static _sa_handler_t nxsig_default_action(int signo)
- {
- int i;
- /* Search the default action table for the entry associated with this
- * signal.
- */
- for (i = 0; i < NACTIONS; i++)
- {
- if (g_defactions[i].signo == signo)
- {
- return g_defactions[i].action;
- }
- }
- /* No default action */
- return SIG_IGN;
- }
- /****************************************************************************
- * Name: nxsig_setup_default_action
- *
- * Description:
- * Setup the default action for a signal.
- *
- * This function is called early in task setup, prior to the creation of
- * any pthreads so we should have exclusive access to the group structure.
- *
- * Input Parameters:
- * group - The group that the task belongs in.
- * action - The new default signal action
- * signo - The signal that will produce this default action
- *
- * Returned Value:
- * None
- *
- ****************************************************************************/
- static void nxsig_setup_default_action(FAR struct task_group_s *group,
- FAR const struct nxsig_defaction_s *info)
- {
- /* Get the address of the handler for this signals default action. */
- if (info->action != SIG_IGN)
- {
- struct sigaction sa;
- /* Attach the signal handler.
- *
- * NOTE: nxsig_action will call nxsig_default(tcb, action, false).
- * Don't be surprised.
- */
- memset(&sa, 0, sizeof(sa));
- sa.sa_handler = info->action;
- sa.sa_flags = SA_SIGINFO;
- (void)nxsig_action(info->signo, &sa, NULL, true);
- /* Indicate that the default signal handler has been attached */
- (void)sigaddset(&group->tg_sigdefault, (int)info->signo);
- }
- }
- /****************************************************************************
- * Public Functions
- ****************************************************************************/
- /****************************************************************************
- * Name: nxsig_isdefault
- *
- * Description:
- * Return true if the specified signal is set to the default action.
- *
- * Input Parameters:
- * tcb - Identifies the thread associated with the default handler
- * signo - The signal number to be queried
- *
- * Returned Value:
- * Zero (OK) is returned on success; A negated errno value is returned
- * on failure.
- *
- ****************************************************************************/
- bool nxsig_isdefault(FAR struct tcb_s *tcb, int signo)
- {
- FAR struct task_group_s *group;
- int ret;
- DEBUGASSERT(tcb != NULL && tcb->group != NULL && GOOD_SIGNO(signo));
- group = tcb->group;
- /* Return true if the signo is marked as using the default action. Return
- * false in all other cases.
- */
- ret = sigismember(&group->tg_sigdefault, signo);
- return ret < 0 ? false : (bool)ret;
- }
- /****************************************************************************
- * Name: nxsig_iscatchable
- *
- * Description:
- * Return true if the specified signal can be caught or ignored.
- *
- * Input Parameters:
- * signo - The signal number to be queried
- *
- * Returned Value:
- * Zero (OK) is returned on success; A negated errno value is returned
- * on failure.
- *
- ****************************************************************************/
- bool nxsig_iscatchable(int signo)
- {
- int i;
- /* Search the default action table for the entry associated with this
- * signal.
- */
- for (i = 0; i < NACTIONS; i++)
- {
- if (g_defactions[i].signo == signo)
- {
- return (g_defactions[i].flags & SIG_FLAG_NOCATCH) == 0;
- }
- }
- /* If it is not in the table, then it is catchable */
- return true;
- }
- /****************************************************************************
- * Name: nxsig_default
- *
- * Description:
- * If 'defaction' is true, then return the default signal handler action
- * for the specified signal and mark that the default signal hander is
- * in place (it is not yet).
- *
- * If 'defaction' is false, then mark that the default signal handler is
- * NOT in place and return SIG_IGN.
- *
- * This function is called form sigaction() to handle actions = SIG_DFL.
- *
- * Input Parameters:
- * tcb - Identifies the thread associated with the default handler
- * signo - The signal number whose behavior will be modified.
- * defaction - True: the default action is in place
- *
- * Returned Value:
- * The address of the default signal action handler is returne on success.
- * SIG_IGN is returned if there is no default action.
- *
- ****************************************************************************/
- _sa_handler_t nxsig_default(FAR struct tcb_s *tcb, int signo, bool defaction)
- {
- FAR struct task_group_s *group;
- _sa_handler_t handler = SIG_IGN;
- irqstate_t flags;
- DEBUGASSERT(tcb != NULL && tcb->group != NULL);
- group = tcb->group;
- /* Are we setting or unsetting the default action? */
- if (defaction)
- {
- /* We are setting the default action. Look up the default action
- * associated with signo.
- */
- handler = nxsig_default_action(signo);
- if (handler != SIG_IGN)
- {
- /* sigaddset() is not atomic (but neither is sigaction()) */
- flags = spin_lock_irqsave();
- (void)sigaddset(&group->tg_sigdefault, signo);
- spin_unlock_irqrestore(flags);
- }
- }
- if (handler == SIG_IGN)
- {
- /* We are unsetting the default action */
- /* sigdelset() is not atomic (but neither is sigaction()) */
- flags = spin_lock_irqsave();
- (void)sigdelset(&group->tg_sigdefault, signo);
- spin_unlock_irqrestore(flags);
- }
- return handler;
- }
- /****************************************************************************
- * Name: nxsig_default_initialize
- *
- * Description:
- * Set all signals to their default action. This is called from nxtask_start
- * to configure the newly started task.
- *
- * Input Parameters:
- * tcb - Identifies the thread associated with the default handlers
- *
- * Returned Value:
- * Zero (OK) is returned on success; A negated errno value is returned
- * on failure.
- *
- ****************************************************************************/
- int nxsig_default_initialize(FAR struct tcb_s *tcb)
- {
- FAR struct task_group_s *group;
- int i;
- DEBUGASSERT(tcb != NULL && tcb->group != NULL);
- group = tcb->group;
- /* Initialize the set of default signal handlers */
- (void)sigemptyset(&group->tg_sigdefault);
- /* Setup the default action for each signal in g_defactions[] */
- for (i = 0; i < NACTIONS; i++)
- {
- nxsig_setup_default_action(group, &g_defactions[i]);
- }
- return OK;
- }
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