source: mainline/ns/ns.c@ 0861786

/*
 * 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>
#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;

int static ping_phone;

static void get_realtime_as(ipc_callid_t callid, ipc_call_t *call)
{
        static void *addr = NULL;
        void *ph_addr;

        if (!addr) {
                ph_addr = (void *)sysinfo_value("clock.faddr");
                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 | AS_AREA_CACHEABLE);
}

int main(int argc, char **argv)
{
        ipc_call_t call;
        ipc_callid_t callid;
        char *as_area;
        
        ipcarg_t retval, arg1, arg2;

        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:
                        get_realtime_as(callid, &call);
                        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, 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;
                        
        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));
}