source: mainline/uspace/srv/ns/service.c@ ee906a6

/*
 * Copyright (c) 2009 Martin Decky
 * 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 ns
 * @{
 */

#include <adt/hash_table.h>
#include <assert.h>
#include <async.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include "service.h"
#include "ns.h"

/** Service hash table item. */
typedef struct {
        ht_link_t link;

        /** Service ID */
        service_t service;

        /** Session to the service */
        async_sess_t *sess;
} hashed_service_t;

static size_t service_key_hash(void *key)
{
        return *(service_t *) key;
}

static size_t service_hash(const ht_link_t *item)
{
        hashed_service_t *service =
            hash_table_get_inst(item, hashed_service_t, link);

        return service->service;
}

static bool service_key_equal(void *key, const ht_link_t *item)
{
        hashed_service_t *service =
            hash_table_get_inst(item, hashed_service_t, link);

        return service->service == *(service_t *) key;
}

/** Operations for service hash table. */
static hash_table_ops_t service_hash_table_ops = {
        .hash = service_hash,
        .key_hash = service_key_hash,
        .key_equal = service_key_equal,
        .equal = NULL,
        .remove_callback = NULL
};

/** Service hash table structure. */
static hash_table_t service_hash_table;

/** Pending connection structure. */
typedef struct {
        link_t link;
        service_t service;         /**< Service ID */
        iface_t iface;             /**< Interface ID */
        ipc_call_t call;           /**< Call waiting for the connection */
} pending_conn_t;

static list_t pending_conn;

errno_t service_init(void)
{
        if (!hash_table_create(&service_hash_table, 0, 0,
            &service_hash_table_ops)) {
                printf("%s: No memory available for services\n", NAME);
                return ENOMEM;
        }

        list_initialize(&pending_conn);

        return EOK;
}

/** Process pending connection requests */
void process_pending_conn(void)
{
loop:
        list_foreach(pending_conn, link, pending_conn_t, pending) {
                ht_link_t *link = hash_table_find(&service_hash_table, &pending->service);
                if (!link)
                        continue;

                hashed_service_t *hashed_service = hash_table_get_inst(link, hashed_service_t, link);
                async_exch_t *exch = async_exchange_begin(hashed_service->sess);
                async_forward_fast(&pending->call, exch, pending->iface,
                    IPC_GET_ARG3(pending->call), 0, IPC_FF_NONE);
                async_exchange_end(exch);

                list_remove(&pending->link);
                free(pending);

                goto loop;
        }
}

/** Register service.
 *
 * @param service Service to be registered.
 * @param phone   Phone to be used for connections to the service.
 * @param call    Pointer to call structure.
 *
 * @return Zero on success or a value from @ref errno.h.
 *
 */
errno_t register_service(service_t service, sysarg_t phone, ipc_call_t *call)
{
        if (hash_table_find(&service_hash_table, &service))
                return EEXIST;

        hashed_service_t *hashed_service =
            (hashed_service_t *) malloc(sizeof(hashed_service_t));
        if (!hashed_service)
                return ENOMEM;

        hashed_service->service = service;
        hashed_service->sess = async_callback_receive(EXCHANGE_SERIALIZE);
        if (hashed_service->sess == NULL)
                return EIO;

        hash_table_insert(&service_hash_table, &hashed_service->link);
        return EOK;
}

/** Connect client to service.
 *
 * @param service  Service to be connected to.
 * @param iface    Interface to be connected to.
 * @param call     Pointer to call structure.
 *
 * @return Zero on success or a value from @ref errno.h.
 *
 */
void connect_to_service(service_t service, iface_t iface, ipc_call_t *call)
{
        sysarg_t flags = IPC_GET_ARG4(*call);
        errno_t retval;

        ht_link_t *link = hash_table_find(&service_hash_table, &service);
        if (!link) {
                if (flags & IPC_FLAG_BLOCKING) {
                        /* Blocking connection, add to pending list */
                        pending_conn_t *pending =
                            (pending_conn_t *) malloc(sizeof(pending_conn_t));
                        if (!pending) {
                                retval = ENOMEM;
                                goto out;
                        }

                        link_initialize(&pending->link);
                        pending->service = service;
                        pending->iface = iface;
                        pending->call = *call;

                        list_append(&pending->link, &pending_conn);
                        return;
                }

                retval = ENOENT;
                goto out;
        }

        hashed_service_t *hashed_service = hash_table_get_inst(link, hashed_service_t, link);
        async_exch_t *exch = async_exchange_begin(hashed_service->sess);
        async_forward_fast(call, exch, iface, IPC_GET_ARG3(*call), 0, IPC_FF_NONE);
        async_exchange_end(exch);
        return;

out:
        async_answer_0(call, retval);
}

/**
 * @}
 */