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/*

 * 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.

 */

/**

 * @file    ns.c

 * @brief   Naming service for HelenOS IPC.

 */

#include <ipc/ipc.h>

#include <ipc/ns.h>

#include <stdio.h>

#include <unistd.h>

#include <stdlib.h>

#include <errno.h>

#include <assert.h>

#include <libadt/list.h>

#include <libadt/hash_table.h>

#define NAME    "NS"

#define NS_HASH_TABLE_CHAINS    20

extern int __DONT_OPEN_STDIO__=1;

static int register_service(ipcarg_t service, ipcarg_t phone, ipc_call_t *call);

static int connect_to_service(ipcarg_t service, ipc_call_t *call, ipc_callid_t callid);

/* Static functions implementing NS hash table operations. */

static hash_index_t ns_hash(unsigned long *key);

static int ns_compare(unsigned long *key, hash_count_t keys, link_t *item);

static void ns_remove(link_t *item);

/** Operations for NS hash table. */

static hash_table_operations_t ns_hash_table_ops = {

    .hash = ns_hash,

    .compare = ns_compare,

    .remove_callback = ns_remove

};

/** NS hash table structure. */

static hash_table_t ns_hash_table;

/** NS hash table item. */

typedef struct {

    link_t link;

    ipcarg_t service;       /**< Number of the service. */

    ipcarg_t phone;         /**< Phone registered with the service. */

    ipcarg_t in_phone_hash;     /**< Incoming phone hash. */

} hashed_service_t;

int static ping_phone;

int main(int argc, char **argv)

{

    ipc_call_t call;

    ipc_callid_t callid;

    char *as_area;

    ipcarg_t retval, arg1, arg2;

//  printf("%s: Naming service started.\n", NAME);

    if (!hash_table_create(&ns_hash_table, NS_HASH_TABLE_CHAINS, 3, &ns_hash_table_ops)) {

//      printf("%s: cannot create hash table\n", NAME);

        return ENOMEM;

    }

    while (1) {

        callid = ipc_wait_for_call(&call);

//      printf("NS: Call in_phone_hash=%lX...", call.in_phone_hash);

        switch (IPC_GET_METHOD(call)) {

        case IPC_M_AS_AREA_SEND:

            as_area = (char *)IPC_GET_ARG2(call);

//          printf("Received as_area: %P, size:%d\n", as_area, IPC_GET_ARG3(call));

            retval = ipc_answer_fast(callid, 0,(sysarg_t)(1024*1024), 0);

            if (!retval) {

//              printf("Reading shared memory...");

//              printf("Text: %s", as_area);

            } else

//              printf("Failed answer: %d\n", retval);

            continue;

            break;

        case IPC_M_INTERRUPT:

//          printf("GOT INTERRUPT: %c\n", IPC_GET_ARG2(call));

            break;

        case IPC_M_PHONE_HUNGUP:

//          printf("Phone hung up.\n");

            retval = 0;

            break;

        case IPC_M_CONNECT_TO_ME:

            /*

             * Server requests service registration.

             */

            retval = register_service(IPC_GET_ARG1(call), IPC_GET_ARG3(call), &call);

            ping_phone = IPC_GET_ARG3(call);

            break;

        case IPC_M_CONNECT_ME_TO:

            /*

             * Client requests to be connected to a service.

             */

            retval = connect_to_service(IPC_GET_ARG1(call), &call, callid);

            break;

        case NS_HANGUP:

//          printf("Closing connection.\n");

            retval = EHANGUP;

            break;

        case NS_PING:

//          printf("Ping...%P %P\n", IPC_GET_ARG1(call),

//                 IPC_GET_ARG2(call));

            retval = 0;

            arg1 = 0xdead;

            arg2 = 0xbeef;

            break;

        case NS_PING_SVC:

//          printf("NS:Pinging service %d\n", ping_phone);

            ipc_call_sync(ping_phone, NS_PING, 0xbeef, 0);

//          printf("NS:Got pong\n");

            break;

        default:

//          printf("Unknown method: %zd\n", IPC_GET_METHOD(call));

            retval = ENOENT;

            break;

        }

        if (! (callid & IPC_CALLID_NOTIFICATION)) {

//          printf("Answering.\n");

            ipc_answer_fast(callid, retval, arg1, arg2);

        }

    }

}

/** Register service.

 *

 * @param service Service to be registered.

 * @param phone 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.

 */

int register_service(ipcarg_t service, ipcarg_t phone, ipc_call_t *call)

{

    unsigned long keys[3] = { service, call->in_phone_hash, 0 };

    hashed_service_t *hs;

//  printf("Registering service %d on phone %d...", service, phone);

    if (hash_table_find(&ns_hash_table, keys)) {

//      printf("Service %d already registered.\n", service);

        return EEXISTS;

    }

    hs = (hashed_service_t *) malloc(sizeof(hashed_service_t));

    if (!hs) {

//      printf("Failed to register service %d.\n", service);

        return ENOMEM;

    }

    link_initialize(&hs->link);

    hs->service = service;

    hs->phone = phone;

    hs->in_phone_hash = call->in_phone_hash;

    hash_table_insert(&ns_hash_table, keys, &hs->link);

    return 0;

}

/** Connect client to service.

 *

 * @param service Service to be connected to.

 * @param call Pointer to call structure.

 * @param callid Call ID of the request.

 *

 * @return Zero on success or a value from @ref errno.h.

 */

int connect_to_service(ipcarg_t service, ipc_call_t *call, ipc_callid_t callid)

{

    unsigned long keys[3] = { service, 0, 0 };

    link_t *hlp;

    hashed_service_t *hs;

    hlp = hash_table_find(&ns_hash_table, keys);

    if (!hlp) {

//      printf("Service %d not registered.\n", service);

        return ENOENT;

    }

    hs = hash_table_get_instance(hlp, hashed_service_t, link);

//  printf("Connecting in_phone_hash=%lX to service at phone %d...", call->in_phone_hash, hs->phone);

    return ipc_forward_fast(callid, hs->phone, 0, 0);

}

/** Compute hash index into NS hash table.

 *

 * @param key Pointer keys. However, only the first key (i.e. service number)

 *        is used to compute the hash index.

 * @return Hash index corresponding to key[0].

 */

hash_index_t ns_hash(unsigned long *key)

{

    assert(key);

    return *key % NS_HASH_TABLE_CHAINS;

}

/** Compare a key with hashed item.

 *

 * This compare function always ignores the third key.

 * It exists only to make it possible to remove records

 * originating from connection with key[1] in_phone_hash

 * value. Note that this is close to being classified

 * as a nasty hack.

 *

 * @param key Array of keys.

 * @param keys Must be lesser or equal to 3.

 * @param item Pointer to a hash table item.

 * @return Non-zero if the key matches the item, zero otherwise.

 */

int ns_compare(unsigned long key[], hash_count_t keys, link_t *item)

{

    hashed_service_t *hs;

    assert(key);

    assert(keys <= 3);

    assert(item);

    hs = hash_table_get_instance(item, hashed_service_t, link);

    if (keys == 2)

        return key[1] == hs->in_phone_hash;

    else

        return key[0] == hs->service;

}

/** Perform actions after removal of item from the hash table.

 *

 * @param item Item that was removed from the hash table.

 */

void ns_remove(link_t *item)

{

    assert(item);

    free(hash_table_get_instance(item, hashed_service_t, link));

}