source: mainline/uspace/lib/c/generic/async/ports.c@ cb20b05

/*
 * Copyright (c) 2025 Jiri Svoboda
 * Copyright (c) 2006 Ondrej Palkovsky
 * 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.
 */

#define _LIBC_ASYNC_C_
#include <ipc/ipc.h>
#include <async.h>
#include "../private/async.h"
#undef _LIBC_ASYNC_C_

#include <ipc/irq.h>
#include <ipc/event.h>
#include <fibril.h>
#include <adt/hash_table.h>
#include <adt/hash.h>
#include <adt/list.h>
#include <assert.h>
#include <errno.h>
#include <time.h>
#include <barrier.h>
#include <stdbool.h>
#include <stdlib.h>
#include <mem.h>
#include <stdlib.h>
#include <macros.h>
#include <as.h>
#include <abi/mm/as.h>
#include "../private/fibril.h"

/** Interface data */
typedef struct {
        ht_link_t link;

        /** Interface ID */
        iface_t iface;

        /** Interface connection handler */
        async_port_handler_t handler;

        /** Client data */
        void *data;
} interface_t;

/* Port data */
typedef struct {
        ht_link_t link;

        /** Port ID */
        port_id_t id;

        /** Port interfaces */
        hash_table_t interface_hash_table;
} port_t;

/** Default fallback fibril function.
 *
 * This fallback fibril function gets called on incomming connections that do
 * not have a specific handler defined.
 *
 * @param call Data of the incoming call.
 * @param arg  Local argument
 *
 */
static void default_fallback_port_handler(ipc_call_t *call, void *arg)
{
        async_answer_0(call, ENOENT);
}

static async_port_handler_t fallback_port_handler =
    default_fallback_port_handler;
static void *fallback_port_data = NULL;

/** Futex guarding the port hash table. */
static fibril_rmutex_t port_mutex;
static hash_table_t port_hash_table;
/** Next available port ID */
static port_id_t port_id_avail = 0;

static size_t interface_key_hash(const void *key)
{
        const iface_t *iface = key;
        return *iface;
}

static size_t interface_hash(const ht_link_t *item)
{
        interface_t *interface = hash_table_get_inst(item, interface_t, link);
        return interface_key_hash(&interface->iface);
}

static bool interface_key_equal(const void *key, size_t hash, const ht_link_t *item)
{
        const iface_t *iface = key;
        interface_t *interface = hash_table_get_inst(item, interface_t, link);
        return *iface == interface->iface;
}

/** Operations for the port hash table. */
static const hash_table_ops_t interface_hash_table_ops = {
        .hash = interface_hash,
        .key_hash = interface_key_hash,
        .key_equal = interface_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

static size_t port_key_hash(const void *key)
{
        const port_id_t *port_id = key;
        return *port_id;
}

static size_t port_hash(const ht_link_t *item)
{
        port_t *port = hash_table_get_inst(item, port_t, link);
        return port_key_hash(&port->id);
}

static bool port_key_equal(const void *key, size_t hash, const ht_link_t *item)
{
        const port_id_t *port_id = key;
        port_t *port = hash_table_get_inst(item, port_t, link);
        return *port_id == port->id;
}

/** Operations for the port hash table. */
static const hash_table_ops_t port_hash_table_ops = {
        .hash = port_hash,
        .key_hash = port_key_hash,
        .key_equal = port_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

static interface_t *async_new_interface(port_t *port, iface_t iface,
    async_port_handler_t handler, void *data)
{
        interface_t *interface =
            (interface_t *) malloc(sizeof(interface_t));
        if (!interface)
                return NULL;
        interface->iface = iface;
        interface->handler = handler;
        interface->data = data;

        hash_table_insert(&port->interface_hash_table, &interface->link);

        return interface;
}

static port_t *async_new_port(void)
{
        // TODO: Move the malloc out of critical section.
        port_t *port = (port_t *) malloc(sizeof(port_t));
        if (!port)
                return NULL;

        bool ret = hash_table_create(&port->interface_hash_table, 0, 0,
            &interface_hash_table_ops);
        if (!ret) {
                free(port);
                return NULL;
        }

        port_id_t id = port_id_avail;
        port_id_avail++;

        port->id = id;
        hash_table_insert(&port_hash_table, &port->link);

        return port;
}

static bool destroy_if(ht_link_t *link, void *arg)
{
        port_t *port = (port_t *)arg;

        hash_table_remove_item(&port->interface_hash_table, link);
        return false;
}

static void async_delete_port(port_t *port)
{
        /* Destroy interfaces */
        hash_table_apply(&port->interface_hash_table, destroy_if, port);

        hash_table_destroy(&port->interface_hash_table);
        free(port);
}

errno_t async_create_port_internal(iface_t iface, async_port_handler_t handler,
    void *data, port_id_t *port_id)
{
        interface_t *interface;

        fibril_rmutex_lock(&port_mutex);

        port_t *port = async_new_port();
        if (port == NULL) {
                fibril_rmutex_unlock(&port_mutex);
                return ENOMEM;
        }

        interface = async_new_interface(port, iface, handler, data);
        if (interface == NULL) {
                async_delete_port(port);
                fibril_rmutex_unlock(&port_mutex);
                return ENOMEM;
        }

        *port_id = port->id;
        fibril_rmutex_unlock(&port_mutex);
        return EOK;
}

errno_t async_port_create_interface(port_id_t port_id, iface_t iface,
    async_port_handler_t handler, void *data)
{
        ht_link_t *link;
        port_t *port;
        interface_t *interface;

        fibril_rmutex_lock(&port_mutex);
        link = hash_table_find(&port_hash_table, &port_id);
        assert(link != NULL);
        port = hash_table_get_inst(link, port_t, link);

        interface = async_new_interface(port, iface, handler, data);
        if (interface == NULL) {
                fibril_rmutex_unlock(&port_mutex);
                return ENOMEM;
        }

        fibril_rmutex_unlock(&port_mutex);
        return EOK;
}

errno_t async_create_port(iface_t iface, async_port_handler_t handler,
    void *data, port_id_t *port_id)
{
        if ((iface & IFACE_MOD_MASK) == IFACE_MOD_CALLBACK)
                return EINVAL;

        return async_create_port_internal(iface, handler, data, port_id);
}

void async_set_fallback_port_handler(async_port_handler_t handler, void *data)
{
        assert(handler != NULL);

        fallback_port_handler = handler;
        fallback_port_data = data;
}

typedef struct {
        iface_t iface;
        interface_t *interface;
} find_if_port_t;

static bool find_if_port(ht_link_t *link, void *arg)
{
        find_if_port_t *fip = (find_if_port_t *)arg;
        port_t *port;
        interface_t *interface;

        (void)arg;
        port = hash_table_get_inst(link, port_t, link);

        ht_link_t *ilink = hash_table_find(&port->interface_hash_table,
            &fip->iface);
        if (ilink) {
                interface = hash_table_get_inst(ilink, interface_t,
                    link);
                fip->interface = interface;
                return false;
        }

        return true;
}

static interface_t *async_find_interface(iface_t iface, port_id_t port_id)
{
        interface_t *interface = NULL;
        find_if_port_t fip;

        (void)port_id; // XXX !!!

        fibril_rmutex_lock(&port_mutex);

        /*
         * XXX Find any port implementing that interface. In reality we should
         * only look at port with ID port_id - but server.c does not
         * provide us with a correct port ID
         */

        fip.iface = iface;
        fip.interface = NULL;
        hash_table_apply(&port_hash_table, find_if_port, (void *)&fip);
        interface = fip.interface;

        fibril_rmutex_unlock(&port_mutex);
        return interface;
}

async_port_handler_t async_get_interface_handler(iface_t iface,
    port_id_t port_id, void **data)
{
        assert(data);

        async_port_handler_t handler = fallback_port_handler;
        *data = fallback_port_data;

        interface_t *interface = async_find_interface(iface, port_id);
        if (interface != NULL) {
                handler = interface->handler;
                *data = interface->data;
        }

        return handler;
}

void async_port_destroy(port_id_t port_id)
{
        ht_link_t *link;
        port_t *port;

        fibril_rmutex_lock(&port_mutex);
        link = hash_table_find(&port_hash_table, &port_id);
        assert(link != NULL);
        port = hash_table_get_inst(link, port_t, link);
        async_delete_port(port);
        fibril_rmutex_unlock(&port_mutex);
}

/** Initialize the async framework ports.
 *
 */
void __async_ports_init(void)
{
        if (fibril_rmutex_initialize(&port_mutex) != EOK)
                abort();

        if (!hash_table_create(&port_hash_table, 0, 0, &port_hash_table_ops))
                abort();
}

void __async_ports_fini(void)
{
        fibril_rmutex_destroy(&port_mutex);
}