/**************************************************************************** * sched/task_exithook.c * * Copyright (C) 2011-2013 Gregory Nutt. All rights reserved. * Author: Gregory Nutt * * 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 #include #include #include #include #include #include #include #include "os_internal.h" #include "sig_internal.h" /**************************************************************************** * Definitions ****************************************************************************/ /**************************************************************************** * Private Type Declarations ****************************************************************************/ /**************************************************************************** * Global Variables ****************************************************************************/ /**************************************************************************** * Private Variables ****************************************************************************/ /**************************************************************************** * Private Function Prototypes ****************************************************************************/ /**************************************************************************** * Private Functions ****************************************************************************/ /**************************************************************************** * Name: task_atexit * * Description: * Call any registerd atexit function(s) * ****************************************************************************/ #if defined(CONFIG_SCHED_ATEXIT) && !defined(CONFIG_SCHED_ONEXIT) static inline void task_atexit(FAR _TCB *tcb) { #if defined(CONFIG_SCHED_ATEXIT_MAX) && CONFIG_SCHED_ATEXIT_MAX > 1 int index; /* Call each atexit function in reverse order of registration atexit() * functions are registered from lower to higher arry indices; they must * be called in the reverse order of registration when task exists, i.e., * from higher to lower indices. */ for (index = CONFIG_SCHED_ATEXIT_MAX-1; index >= 0; index--) { if (tcb->atexitfunc[index]) { /* Call the atexit function */ (*tcb->atexitfunc[index])(); /* Nullify the atexit function. task_exithook may be called more then * once in most task exit scenarios. Nullifying the atext function * pointer will assure that the callback is performed only once. */ tcb->atexitfunc[index] = NULL; } } #else if (tcb->atexitfunc) { /* Call the atexit function */ (*tcb->atexitfunc)(); /* Nullify the atexit function. task_exithook may be called more then * once in most task exit scenarios. Nullifying the atext function * pointer will assure that the callback is performed only once. */ tcb->atexitfunc = NULL; } #endif } #else # define task_atexit(tcb) #endif /**************************************************************************** * Name: task_onexit * * Description: * Call any registerd on)exit function(s) * ****************************************************************************/ #ifdef CONFIG_SCHED_ONEXIT static inline void task_onexit(FAR _TCB *tcb, int status) { #if defined(CONFIG_SCHED_ONEXIT_MAX) && CONFIG_SCHED_ONEXIT_MAX > 1 int index; /* Call each on_exit function in reverse order of registration. on_exit() * functions are registered from lower to higher arry indices; they must * be called in the reverse order of registration when task exists, i.e., * from higher to lower indices. */ for (index = CONFIG_SCHED_ONEXIT_MAX-1; index >= 0; index--) { if (tcb->onexitfunc[index]) { /* Call the on_exit function */ (*tcb->onexitfunc[index])(status, tcb->onexitarg[index]); /* Nullify the on_exit function. task_exithook may be called more then * once in most task exit scenarios. Nullifying the atext function * pointer will assure that the callback is performed only once. */ tcb->onexitfunc[index] = NULL; } } #else if (tcb->onexitfunc) { /* Call the on_exit function */ (*tcb->onexitfunc)(status, tcb->onexitarg); /* Nullify the on_exit function. task_exithook may be called more then * once in most task exit scenarios. Nullifying the on_exit function * pointer will assure that the callback is performed only once. */ tcb->onexitfunc = NULL; } #endif } #else # define task_onexit(tcb,status) #endif /**************************************************************************** * Name: task_sigchild * * Description: * Send the SIGCHILD signal to the parent thread * ****************************************************************************/ #ifdef CONFIG_SCHED_HAVE_PARENT static inline void task_sigchild(FAR _TCB *tcb, int status) { FAR _TCB *ptcb; siginfo_t info; /* Only exiting tasks should generate SIGCHLD. pthreads use other * mechansims. */ if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_TASK) { /* Keep things stationary through the following */ sched_lock(); /* Get the TCB of the receiving task */ ptcb = sched_gettcb(tcb->parent); if (!ptcb) { /* The parent no longer exists... bail */ sched_unlock(); return; } #ifdef CONFIG_SCHED_CHILD_STATUS /* Check if the parent task has suppressed retention of child exit * status information. Only 'tasks' report exit status, not pthreads. * pthreads have a different mechanism. */ if ((ptcb->flags & TCB_FLAG_NOCLDWAIT) == 0) { FAR struct child_status_s *child; /* No.. Find the exit status entry for this task in the parent TCB */ child = task_findchild(ptcb, getpid()); DEBUGASSERT(child); if (child) { /* Mark that the child has exit'ed */ child->ch_flags |= CHILD_FLAG_EXITED; /* Save the exit status */ child->ch_status = status; } } #else /* Decrement the number of children from this parent */ DEBUGASSERT(ptcb->nchildren > 0); ptcb->nchildren--; #endif /* Set the parent to an impossible PID. We do this because under * certain conditions, task_exithook() can be called multiple times. * If this function is called again, sched_gettcb() will fail on the * invalid parent PID above, nchildren will be decremented once and * all will be well. */ tcb->parent = INVALID_PROCESS_ID; /* Create the siginfo structure. We don't actually know the cause. * That is a bug. Let's just say that the child task just exit-ted * for now. */ info.si_signo = SIGCHLD; info.si_code = CLD_EXITED; info.si_value.sival_ptr = NULL; info.si_pid = tcb->pid; info.si_status = status; /* Send the signal. We need to use this internal interface so that we * can provide the correct si_code value with the signal. */ (void)sig_received(ptcb, &info); sched_unlock(); } } #else # define task_sigchild(tcb,status) #endif /**************************************************************************** * Name: task_exitwakeup * * Description: * Wakeup any tasks waiting for this task to exit * ****************************************************************************/ #if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT) static inline void task_exitwakeup(FAR _TCB *tcb, int status) { /* Wakeup any tasks waiting for this task to exit */ while (tcb->exitsem.semcount < 0) { /* "If more than one thread is suspended in waitpid() awaiting * termination of the same process, exactly one thread will return * the process status at the time of the target process termination." * Hmmm.. what do we return to the others? */ if (tcb->stat_loc) { *tcb->stat_loc = status << 8; tcb->stat_loc = NULL; } /* Wake up the thread */ sem_post(&tcb->exitsem); } } #else # define task_exitwakeup(tcb, status) #endif /**************************************************************************** * Public Functions ****************************************************************************/ /**************************************************************************** * Name: task_hook * * Description: * This function implements some of the internal logic of exit() and * task_delete(). This function performs some cleanup and other actions * required when a task exists: * * - All open streams are flushed and closed. * - All functions registered with atexit() and on_exit() are called, in * the reverse order of their registration. * * When called from exit(), the tcb still resides at the head of the ready- * to-run list. The following logic is safe because we will not be * returning from the exit() call. * * When called from task_delete() we are operating on a different thread; * on the thread that called task_delete(). In this case, task_delete * will have already removed the tcb from the ready-to-run list to prevent * any further action on this task. * ****************************************************************************/ void task_exithook(FAR _TCB *tcb, int status) { /* If exit function(s) were registered, call them now before we do any un- * initialization. NOTE: In the case of task_delete(), the exit function * will *not* be called on the thread execution of the task being deleted! */ task_atexit(tcb); /* Call any registered on_exit function(s) */ task_onexit(tcb, status); /* Send SIGCHLD to the parent of the exit-ing task */ task_sigchild(tcb, status); /* Wakeup any tasks waiting for this task to exit */ task_exitwakeup(tcb, status); /* Flush all streams (File descriptors will be closed when * the TCB is deallocated). */ #if CONFIG_NFILE_STREAMS > 0 (void)lib_flushall(tcb->streams); #endif /* Discard any un-reaped child status (no zombies here!) */ #if defined(CONFIG_SCHED_HAVE_PARENT) && defined(CONFIG_SCHED_CHILD_STATUS) task_removechildren(tcb); #endif /* Free all file-related resources now. This gets called again * just be be certain when the TCB is delallocated. However, we * really need to close files as soon as possible while we still * have a functioning task. */ (void)sched_releasefiles(tcb); /* Deallocate anything left in the TCB's queues */ #ifndef CONFIG_DISABLE_SIGNALS sig_cleanup(tcb); /* Deallocate Signal lists */ #endif }