source: mainline/uspace/srv/ns/ns.c@ a78d001

/*
 * 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,
                        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,
                0
        };
        
        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,
                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));
}

/**
 * @}
 */