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/*

 * 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)

{

    ipl_t ipl;

    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 the task was being debugged, clean up debugging session.

     * This is necessarry as slamming the phones won't force

     * kbox thread to clean it up since sender != debugger.

     */

    ipl = interrupts_disable();

    spinlock_lock(&TASK->lock);

    udebug_task_cleanup(TASK);

    spinlock_unlock(&TASK->lock);

    interrupts_restore(ipl);

    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);

}

/** Handle hangup message in kbox.

 *

 * @param call  The IPC_M_PHONE_HUNGUP call structure.

 * @param last  Output, the function stores @c true here if

 *      this was the last phone, @c false otherwise.

 **/

static void kbox_proc_phone_hungup(call_t *call, bool *last)

{

    ipl_t ipl;

    LOG("kbox_proc_phone_hungup()\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. Detach this thread so it

         * gets freed and signal to the caller.

         */

        /* Only detach kbox thread unless already terminating. */

        mutex_lock(&TASK->kb_cleanup_lock);

        if (&TASK->kb_finished == false) {

            /* Detach kbox thread so it gets freed from memory. */

            thread_detach(TASK->kb_thread);

            TASK->kb_thread = NULL;

        }

        mutex_unlock(&TASK->kb_cleanup_lock);

        LOG("phone list is empty\n");

        *last = true;

    } else {

        *last = false;

    }

    spinlock_unlock(&TASK->answerbox.lock);

    spinlock_unlock(&TASK->lock);

    interrupts_restore(ipl);

}

/** Implementing function for the kbox thread.

 *

 * This function listens for debug requests. It terminates

 * when all phones are disconnected from the kbox.

 *

 * @param arg   Ignored.

 */

static void kbox_thread_proc(void *arg)

{

    call_t *call;

    bool done;

    (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)

            continue;   /* Try again. */

        switch (IPC_GET_METHOD(call->data)) {

        case IPC_M_DEBUG_ALL:

            /* Handle debug call. */

            udebug_call_receive(call);

            break;

        case IPC_M_PHONE_HUNGUP:

            /*

             * Process the hangup call. If this was the last

             * phone, done will be set to true and the

             * while loop will terminate.

             */

            kbox_proc_phone_hungup(call, &done);

            break;

        default:

            /* Ignore */

            break;

        }

    }

    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;

}

/** @}

 */