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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.
 */


/** @defgroup ns Naming Service
 * @brief   Naming service for HelenOS IPC.
 * @{
 */


/**
 * @file    ns.c
 * @brief   Naming service for HelenOS IPC.
 */



#include <ipc/ipc.h>
#include <ipc/ns.h>
#include <ipc/services.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>
#include <sysinfo.h>
#include <ddi.h>
#include <as.h>

#define NAME    "NS"

#define NS_HASH_TABLE_CHAINS    20

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;

static void *clockaddr = NULL;
static void *klogaddr = NULL;

static void get_as(ipc_callid_t callid, ipc_call_t *call, char *name, void **addr)
{
    void *ph_addr;

    if (!*addr) {
        ph_addr = (void *)sysinfo_value(name);
        if (!ph_addr) {
            ipc_answer_fast(callid, ENOENT, 0, 0);
            return;
        }
        *addr = as_get_mappable_page(PAGE_SIZE);
        map_physmem(ph_addr, *addr, 1, AS_AREA_READ | AS_AREA_CACHEABLE);
    }
    ipc_answer_fast(callid, 0, (ipcarg_t)*addr, AS_AREA_READ);
}

int main(int argc, char **argv)
{
    ipc_call_t call;
    ipc_callid_t callid;
   
    ipcarg_t retval;

    if (!hash_table_create(&ns_hash_table, NS_HASH_TABLE_CHAINS, 3, &ns_hash_table_ops)) {
        return ENOMEM;
    }
       
    while (1) {
        callid = ipc_wait_for_call(&call);
        switch (IPC_GET_METHOD(call)) {
        case IPC_M_AS_AREA_RECV:
            switch (IPC_GET_ARG3(call)) {
            case SERVICE_MEM_REALTIME:
                get_as(callid, &call, "clock.faddr", &clockaddr);
                break;
            case SERVICE_MEM_KLOG:
                get_as(callid, &call, "klog.faddr", &klogaddr);
                break;
            default:
                ipc_answer_fast(callid, ENOENT, 0, 0);
            }
            continue;
        case IPC_M_PHONE_HUNGUP:
            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);
            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;
        default:
            retval = ENOENT;
            break;
        }
        if (! (callid & IPC_CALLID_NOTIFICATION)) {
            ipc_answer_fast(callid, retval, 0, 0);
        }
    }
}

/** 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;
           
    if (hash_table_find(&ns_hash_table, keys)) {
        return EEXISTS;
    }
           
    hs = (hashed_service_t *) malloc(sizeof(hashed_service_t));
    if (!hs) {
        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) {
        return ENOENT;
    }
    hs = hash_table_get_instance(hlp, hashed_service_t, link);
    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));
}

/**
 * @}
 */