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Diffstat (limited to 'nuttx/sched/task_delete.c')
-rw-r--r-- | nuttx/sched/task_delete.c | 194 |
1 files changed, 194 insertions, 0 deletions
diff --git a/nuttx/sched/task_delete.c b/nuttx/sched/task_delete.c new file mode 100644 index 000000000..ea0e251db --- /dev/null +++ b/nuttx/sched/task_delete.c @@ -0,0 +1,194 @@ +/**************************************************************************** + * sched/task_delete.c + * + * Copyright (C) 2007-2009, 2011-2012 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 <stdlib.h> +#include <sched.h> + +#include "os_internal.h" +#ifndef CONFIG_DISABLE_SIGNALS +# include "sig_internal.h" +#endif + +/**************************************************************************** + * Definitions + ****************************************************************************/ + +/**************************************************************************** + * Private Type Declarations + ****************************************************************************/ + +/**************************************************************************** + * Global Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Variables + ****************************************************************************/ + +/**************************************************************************** + * Private Function Prototypes + ****************************************************************************/ + +/**************************************************************************** + * Private Functions + ****************************************************************************/ + +/**************************************************************************** + * Public Functions + ****************************************************************************/ + +/**************************************************************************** + * Name: task_delete + * + * Description: + * This function causes a specified task to cease to exist. Its stack and + * TCB will be deallocated. This function is the companion to task_create(). + * + * The logic in this function only deletes non-running tasks. If the 'pid' + * parameter refers to to the currently runing task, then processing is + * redirected to exit(). + * + * Control will still be returned to task_delete() after the exit() logic + * finishes. In fact, this function is the final function called all task + * termination sequences. Here are all possible exit scenarios: + * + * - pthread_exit(). Calls exit() + * - exit(). Calls _exit() + * - _exit(). Calls task_deletecurrent() making the currently running task + * non-running then calls task_delete() to terminate the non-running + * task. + * - task_delete() + * + * Inputs: + * pid - The task ID of the task to delete. A pid of zero + * signifies the calling task. + * + * Return Value: + * OK on success; or ERROR on failure + * + * This function can fail if the provided pid does not correspond to a + * task (errno is not set) + * + ****************************************************************************/ + +int task_delete(pid_t pid) +{ + FAR _TCB *rtcb; + FAR _TCB *dtcb; + irqstate_t saved_state; + int ret = ERROR; + + /* Check if the task to delete is the calling task */ + + rtcb = (FAR _TCB*)g_readytorun.head; + if (pid == 0 || pid == rtcb->pid) + { + /* If it is, then what we really wanted to do was exit. Note that we + * don't bother to unlock the TCB since it will be going away. + */ + + exit(EXIT_SUCCESS); + } + + /* Make sure the task does not become ready-to-run while we are futzing with + * its TCB by locking ourselves as the executing task. + */ + + sched_lock(); + + /* Find for the TCB associated with matching pid */ + + dtcb = sched_gettcb(pid); + if (!dtcb) + { + /* This pid does not correspond to any known task */ + + sched_unlock(); + return ERROR; + } + + /* Verify our internal sanity */ + + if (dtcb->task_state == TSTATE_TASK_RUNNING || + dtcb->task_state >= NUM_TASK_STATES) + { + sched_unlock(); + PANIC(OSERR_BADDELETESTATE); + } + + /* Perform common task termination logic (flushing streams, calling + * functions registered by at_exit/on_exit, etc.). We need to do + * this as early as possible so that higher level clean-up logic + * can run in a healthy tasking environment. + * + * In the case where the task exits via exit(), task_exithook() + * may be called twice. + * + * I suppose EXIT_SUCCESS is an appropriate return value??? + */ + + task_exithook(dtcb, EXIT_SUCCESS); + + /* Remove the task from the OS's tasks lists. */ + + saved_state = irqsave(); + dq_rem((FAR dq_entry_t*)dtcb, (dq_queue_t*)g_tasklisttable[dtcb->task_state].list); + dtcb->task_state = TSTATE_TASK_INVALID; + irqrestore(saved_state); + + /* At this point, the TCB should no longer be accessible to the system */ + + sched_unlock(); + + /* Since all tasks pass through this function as the final step in their + * exit sequence, this is an appropriate place to inform any instrumentation + * layer that the task no longer exists. + */ + + sched_note_stop(dtcb); + + /* Deallocate its TCB */ + + sched_releasetcb(dtcb); + return ret; +} + |