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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.

 */

/** @addtogroup ns

 * @{

 */

/**

 * @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 <bool.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 <loader/loader.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 void connect_to_service(ipcarg_t service, ipc_call_t *call,

    ipc_callid_t callid);

void register_clonable(ipcarg_t service, ipcarg_t phone, ipc_call_t *call,

    ipc_callid_t callid);

void connect_to_clonable(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;

/** Pending connection structure. */

typedef struct {

    link_t link;

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

    ipc_callid_t callid;     /**< Call ID waiting for the connection */

    ipcarg_t arg2;           /**< Second argument */

    ipcarg_t arg3;           /**< Third argument */

} pending_req_t;

static link_t pending_req;

/** Request for connection to a clonable service. */

typedef struct {

    link_t link;

    ipcarg_t service;

    ipc_call_t call;

    ipc_callid_t callid;

} cs_req_t;

/** List of clonable-service connection requests. */

static link_t cs_req;

static void *clockaddr = NULL;

static void *klogaddr = NULL;

/** Return true if @a service is clonable. */

static bool service_clonable(int service)

{

    return (service == SERVICE_LOAD);

}

static void get_as_area(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_0(callid, ENOENT);

            return;

        }

        *addr = as_get_mappable_page(PAGE_SIZE);

        if (physmem_map(ph_addr, *addr, 1,

            AS_AREA_READ | AS_AREA_CACHEABLE) != 0) {

            ipc_answer_0(callid, ENOENT);

            return;

        }

    }

    ipc_answer_2(callid, EOK, (ipcarg_t) *addr, AS_AREA_READ);

}

/** Process pending connection requests */

static void process_pending_req()

{

    link_t *cur;

loop:

    for (cur = pending_req.next; cur != &pending_req; cur = cur->next) {

        pending_req_t *pr = list_get_instance(cur, pending_req_t, link);

        unsigned long keys[3] = {

            pr->service,

            0,

        };

        link_t *link = hash_table_find(&ns_hash_table, keys);

        if (!link)

            continue;

        hashed_service_t *hs = hash_table_get_instance(link, hashed_service_t, link);

        ipcarg_t retval = ipc_forward_fast(pr->callid, hs->phone,

            pr->arg2, pr->arg3, 0, IPC_FF_NONE);

        if (!(pr->callid & IPC_CALLID_NOTIFICATION))

            ipc_answer_0(pr->callid, retval);

        list_remove(cur);

        free(pr);

        goto loop;

    }

}

int main(int argc, char **argv)

{

    printf(NAME ": HelenOS IPC Naming Service\n");

    if (!hash_table_create(&ns_hash_table, NS_HASH_TABLE_CHAINS, 3,

        &ns_hash_table_ops)) {

        printf(NAME ": No memory available for services\n");

        return ENOMEM;

    }

    list_initialize(&pending_req);

    list_initialize(&cs_req);

    printf(NAME ": Accepting connections\n");

    while (true) {

        process_pending_req();

        ipc_call_t call;

        ipc_callid_t callid = ipc_wait_for_call(&call);

        ipcarg_t retval;

        switch (IPC_GET_METHOD(call)) {

        case IPC_M_SHARE_IN:

            switch (IPC_GET_ARG3(call)) {

            case SERVICE_MEM_REALTIME:

                get_as_area(callid, &call, "clock.faddr", &clockaddr);

                break;

            case SERVICE_MEM_KLOG:

                get_as_area(callid, &call, "klog.faddr", &klogaddr);

                break;

            default:

                ipc_answer_0(callid, ENOENT);

            }

            continue;

        case IPC_M_PHONE_HUNGUP:

            retval = EOK;

            break;

        case IPC_M_CONNECT_TO_ME:

            /*

             * Server requests service registration.

             */

            if (service_clonable(IPC_GET_ARG1(call))) {

                register_clonable(IPC_GET_ARG1(call),

                    IPC_GET_ARG5(call), &call, callid);

                continue;

            } else {

                retval = register_service(IPC_GET_ARG1(call),

                    IPC_GET_ARG5(call), &call);

            }

            break;

        case IPC_M_CONNECT_ME_TO:

            /*

             * Client requests to be connected to a service.

             */

            if (service_clonable(IPC_GET_ARG1(call))) {

                connect_to_clonable(IPC_GET_ARG1(call),

                    &call, callid);

                continue;

            } else {

                connect_to_service(IPC_GET_ARG1(call), &call,

                    callid);

                continue;

            }

            break;

        default:

            retval = ENOENT;

            break;

        }

        if (!(callid & IPC_CALLID_NOTIFICATION))

            ipc_answer_0(callid, retval);

    }

    /* Not reached */

    return 0;

}

/** 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.

 *

 */

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

{

    unsigned long keys[3] = {

        service,

        call->in_phone_hash,

    };

    if (hash_table_find(&ns_hash_table, keys))

        return EEXISTS;

    hashed_service_t *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.

 *

 */

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

{

    ipcarg_t retval;

    unsigned long keys[3] = {

        service,

        0,

    };

    link_t *link = hash_table_find(&ns_hash_table, keys);

    if (!link) {

        if (IPC_GET_ARG4(*call) & IPC_FLAG_BLOCKING) {

            /* Blocking connection, add to pending list */

            pending_req_t *pr = (pending_req_t *) malloc(sizeof(pending_req_t));

            if (!pr) {

                retval = ENOMEM;

                goto out;

            }

            pr->service = service;

            pr->callid = callid;

            pr->arg2 = IPC_GET_ARG2(*call);

            pr->arg3 = IPC_GET_ARG3(*call);

            list_append(&pr->link, &pending_req);

            return;

        }

        retval = ENOENT;

        goto out;

    }

    hashed_service_t *hs = hash_table_get_instance(link, hashed_service_t, link);

    retval = ipc_forward_fast(callid, hs->phone, IPC_GET_ARG2(*call),

        IPC_GET_ARG3(*call), 0, IPC_FF_NONE);

out:

    if (!(callid & IPC_CALLID_NOTIFICATION))

        ipc_answer_0(callid, retval);

}

/** Register clonable service.

 *

 * @param service Service to be registered.

 * @param phone   Phone to be used for connections to the service.

 * @param call    Pointer to call structure.

 *

 */

void register_clonable(ipcarg_t service, ipcarg_t phone, ipc_call_t *call,

    ipc_callid_t callid)

{

    if (list_empty(&cs_req)) {

        /* There was no pending connection request. */

        printf(NAME ": Unexpected clonable server.\n");

        ipc_answer_0(callid, EBUSY);

        return;

    }

    cs_req_t *csr = list_get_instance(cs_req.next, cs_req_t, link);

    list_remove(&csr->link);

    /* Currently we can only handle a single type of clonable service. */

    assert(csr->service == SERVICE_LOAD);

    ipc_answer_0(callid, EOK);

    int rc = ipc_forward_fast(csr->callid, phone, IPC_GET_ARG2(csr->call),

        IPC_GET_ARG3(csr->call), 0, IPC_FF_NONE);

    free(csr);

    ipc_hangup(phone);

}

/** Connect client to clonable 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.

 *

 */

void connect_to_clonable(ipcarg_t service, ipc_call_t *call,

    ipc_callid_t callid)

{

    assert(service == SERVICE_LOAD);

    cs_req_t *csr = malloc(sizeof(cs_req_t));

    if (csr == NULL) {

        ipc_answer_0(callid, ENOMEM);

        return;

    }

    /* Spawn a loader. */

    int rc = loader_spawn("loader");

    if (rc < 0) {

        free(csr);

        ipc_answer_0(callid, rc);

        return;

    }

    csr->service = service;

    csr->call = *call;

    csr->callid = callid;

    /*

     * We can forward the call only after the server we spawned connects

     * to us. Meanwhile we might need to service more connection requests.

     * Thus we store the call in a queue.

     */

    list_append(&csr->link, &cs_req);

}

/** 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)

{

    assert(key);

    assert(keys <= 3);

    assert(item);

    hashed_service_t *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));

}

/**

 * @}

 */