Archipelago » qemu

/*

 * GThread coroutine initialization code

 *

 * Copyright (C) 2006  Anthony Liguori <anthony@codemonkey.ws>

 * Copyright (C) 2011  Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

 *

 * This library is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.0 of the License, or (at your option) any later version.

 *

 * This library is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with this library; if not, see <http://www.gnu.org/licenses/>.

 */

#include <glib.h>

#include "qemu-common.h"

#include "qemu-coroutine-int.h"

typedef struct {

    Coroutine base;

    GThread *thread;

    bool runnable;

    CoroutineAction action;

} CoroutineGThread;

static GCond *coroutine_cond;

static GStaticMutex coroutine_lock = G_STATIC_MUTEX_INIT;

static GStaticPrivate coroutine_key = G_STATIC_PRIVATE_INIT;

static void __attribute__((constructor)) coroutine_init(void)

{

    if (!g_thread_supported()) {

        g_thread_init(NULL);

    }

    coroutine_cond = g_cond_new();

}

static void coroutine_wait_runnable_locked(CoroutineGThread *co)

{

    while (!co->runnable) {

        g_cond_wait(coroutine_cond, g_static_mutex_get_mutex(&coroutine_lock));

    }

}

static void coroutine_wait_runnable(CoroutineGThread *co)

{

    g_static_mutex_lock(&coroutine_lock);

    coroutine_wait_runnable_locked(co);

    g_static_mutex_unlock(&coroutine_lock);

}

static gpointer coroutine_thread(gpointer opaque)

{

    CoroutineGThread *co = opaque;

    g_static_private_set(&coroutine_key, co, NULL);

    coroutine_wait_runnable(co);

    co->base.entry(co->base.entry_arg);

    qemu_coroutine_switch(&co->base, co->base.caller, COROUTINE_TERMINATE);

    return NULL;

}

Coroutine *qemu_coroutine_new(void)

{

    CoroutineGThread *co;

    co = g_malloc0(sizeof(*co));

    co->thread = g_thread_create_full(coroutine_thread, co, 0, TRUE, TRUE,

                                      G_THREAD_PRIORITY_NORMAL, NULL);

    if (!co->thread) {

        g_free(co);

        return NULL;

    }

    return &co->base;

}

void qemu_coroutine_delete(Coroutine *co_)

{

    CoroutineGThread *co = DO_UPCAST(CoroutineGThread, base, co_);

    g_thread_join(co->thread);

    g_free(co);

}

CoroutineAction qemu_coroutine_switch(Coroutine *from_,

                                      Coroutine *to_,

                                      CoroutineAction action)

{

    CoroutineGThread *from = DO_UPCAST(CoroutineGThread, base, from_);

    CoroutineGThread *to = DO_UPCAST(CoroutineGThread, base, to_);

    g_static_mutex_lock(&coroutine_lock);

    from->runnable = false;

    from->action = action;

    to->runnable = true;

    to->action = action;

    g_cond_broadcast(coroutine_cond);

    if (action != COROUTINE_TERMINATE) {

        coroutine_wait_runnable_locked(from);

    }

    g_static_mutex_unlock(&coroutine_lock);

    return from->action;

}

Coroutine *qemu_coroutine_self(void)

{

    CoroutineGThread *co = g_static_private_get(&coroutine_key);

    if (!co) {

        co = g_malloc0(sizeof(*co));

        co->runnable = true;

        g_static_private_set(&coroutine_key, co, (GDestroyNotify)g_free);

    }

    return &co->base;

}

bool qemu_in_coroutine(void)

{

    CoroutineGThread *co = g_static_private_get(&coroutine_key);

    return co && co->base.caller;

}