source: mainline/kernel/generic/src/ipc/kbox.c@ e028660

/*
 * Copyright (c) 2008 Jiri Svoboda
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - 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.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
 */

/** @addtogroup genericipc
 * @{
 */
/** @file
 */

#include <synch/synch.h>
#include <synch/spinlock.h>
#include <synch/mutex.h>
#include <ipc/ipc.h>
#include <ipc/ipcrsc.h>
#include <arch.h>
#include <errno.h>
#include <debug.h>
#include <udebug/udebug_ipc.h>
#include <ipc/kbox.h>

void ipc_kbox_cleanup(void)
{
        bool have_kb_thread;

        /* Only hold kb_cleanup_lock while setting kb_finished - this is enough */
        mutex_lock(&TASK->kb_cleanup_lock);
        TASK->kb_finished = true;
        mutex_unlock(&TASK->kb_cleanup_lock);

        have_kb_thread = (TASK->kb_thread != NULL);

        /* From now on nobody will try to connect phones or attach kbox threads */

        /*
         * Disconnect all phones connected to our kbox. Passing true for
         * notify_box causes a HANGUP message to be inserted for each
         * disconnected phone. This ensures the kbox thread is going to
         * wake up and terminate.
         */
        ipc_answerbox_slam_phones(&TASK->kernel_box, have_kb_thread);
        
        if (have_kb_thread) {
                LOG("join kb_thread..\n");
                thread_join(TASK->kb_thread);
                thread_detach(TASK->kb_thread);
                LOG("join done\n");
                TASK->kb_thread = NULL;
        }

        /* Answer all messages in 'calls' and 'dispatched_calls' queues */
        spinlock_lock(&TASK->kernel_box.lock);
        ipc_cleanup_call_list(&TASK->kernel_box.dispatched_calls);
        ipc_cleanup_call_list(&TASK->kernel_box.calls);
        spinlock_unlock(&TASK->kernel_box.lock);
}


static void kbox_thread_proc(void *arg)
{
        call_t *call;
        int method;
        bool done;
        ipl_t ipl;

        (void)arg;
        LOG("kbox_thread_proc()\n");
        done = false;

        while (!done) {
                call = ipc_wait_for_call(&TASK->kernel_box, SYNCH_NO_TIMEOUT,
                        SYNCH_FLAGS_NONE);

                if (call != NULL) {
                        method = IPC_GET_METHOD(call->data);

                        if (method == IPC_M_DEBUG_ALL) {
                                udebug_call_receive(call);
                        }

                        if (method == IPC_M_PHONE_HUNGUP) {
                                LOG("kbox: handle hangup message\n");

                                /* Was it our debugger, who hung up? */
                                if (call->sender == TASK->udebug.debugger) {
                                        /* Terminate debugging session (if any) */
                                        LOG("kbox: terminate debug session\n");
                                        ipl = interrupts_disable();
                                        spinlock_lock(&TASK->lock);
                                        udebug_task_cleanup(TASK);
                                        spinlock_unlock(&TASK->lock);
                                        interrupts_restore(ipl);
                                } else {
                                        LOG("kbox: was not debugger\n");
                                }

                                LOG("kbox: continue with hangup message\n");
                                IPC_SET_RETVAL(call->data, 0);
                                ipc_answer(&TASK->kernel_box, call);

                                ipl = interrupts_disable();
                                spinlock_lock(&TASK->lock);
                                spinlock_lock(&TASK->answerbox.lock);
                                if (list_empty(&TASK->answerbox.connected_phones)) {
                                        /* Last phone has been disconnected */
                                        TASK->kb_thread = NULL;
                                        done = true;
                                        LOG("phone list is empty\n");
                                }
                                spinlock_unlock(&TASK->answerbox.lock);
                                spinlock_unlock(&TASK->lock);
                                interrupts_restore(ipl);
                        }
                }
        }

        LOG("kbox: finished\n");
}


/**
 * Connect phone to a task kernel-box specified by id.
 *
 * Note that this is not completely atomic. For optimisation reasons,
 * The task might start cleaning up kbox after the phone has been connected
 * and before a kbox thread has been created. This must be taken into account
 * in the cleanup code.
 *
 * @return              Phone id on success, or negative error code.
 */
int ipc_connect_kbox(task_id_t taskid)
{
        int newphid;
        task_t *ta;
        thread_t *kb_thread;
        ipl_t ipl;

        ipl = interrupts_disable();
        spinlock_lock(&tasks_lock);

        ta = task_find_by_id(taskid);
        if (ta == NULL) {
                spinlock_unlock(&tasks_lock);
                interrupts_restore(ipl);
                return ENOENT;
        }

        atomic_inc(&ta->refcount);

        spinlock_unlock(&tasks_lock);
        interrupts_restore(ipl);

        mutex_lock(&ta->kb_cleanup_lock);

        if (atomic_predec(&ta->refcount) == 0) {
                mutex_unlock(&ta->kb_cleanup_lock);
                task_destroy(ta);
                return ENOENT;
        }

        if (ta->kb_finished != false) {
                mutex_unlock(&ta->kb_cleanup_lock);
                return EINVAL;
        }

        newphid = phone_alloc();
        if (newphid < 0) {
                mutex_unlock(&ta->kb_cleanup_lock);
                return ELIMIT;
        }

        /* Connect the newly allocated phone to the kbox */
        ipc_phone_connect(&TASK->phones[newphid], &ta->kernel_box);

        if (ta->kb_thread != NULL) {
                mutex_unlock(&ta->kb_cleanup_lock);
                return newphid;
        }

        /* Create a kbox thread */
        kb_thread = thread_create(kbox_thread_proc, NULL, ta, 0, "kbox", false);
        if (!kb_thread) {
                mutex_unlock(&ta->kb_cleanup_lock);
                return ENOMEM;
        }

        ta->kb_thread = kb_thread;
        thread_ready(kb_thread);

        mutex_unlock(&ta->kb_cleanup_lock);

        return newphid;
}

/** @}
 */