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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 libc

 * @{

 * @}

 */

/** @addtogroup libcipc IPC

 * @brief HelenOS uspace IPC

 * @{

 * @ingroup libc

 */

/** @file

 */

#include <ipc/ipc.h>

#include <libc.h>

#include <malloc.h>

#include <errno.h>

#include <libadt/list.h>

#include <stdio.h>

#include <unistd.h>

#include <futex.h>

#include <kernel/synch/synch.h>

#include <async.h>

#include <fibril.h>

#include <assert.h>

/**

 * Structures of this type are used for keeping track of sent asynchronous calls

 * and queing unsent calls.

 */

typedef struct {

    link_t list;

    ipc_async_callback_t callback;

    void *private;

    union {

        ipc_callid_t callid;

        struct {

            ipc_call_t data;

            int phoneid;

        } msg;

    } u;

    fid_t fid;  /**< Fibril waiting for sending this call. */

} async_call_t;

LIST_INITIALIZE(dispatched_calls);

/** List of asynchronous calls that were not accepted by kernel.

 *

 * It is protected by async_futex, because if the call cannot be sent into the

 * kernel, the async framework is used automatically.

 */

LIST_INITIALIZE(queued_calls);

static atomic_t ipc_futex = FUTEX_INITIALIZER;

/** Make a fast synchronous call.

 *

 * Only three payload arguments can be passed using this function. However, this

 * function is faster than the generic ipc_call_sync_slow() because the payload

 * is passed directly in registers.

 *

 * @param phoneid   Phone handle for the call.

 * @param method    Requested method.

 * @param arg1      Service-defined payload argument.

 * @param arg2      Service-defined payload argument.

 * @param arg3      Service-defined payload argument.

 * @param result1   If non-NULL, the return ARG1 will be stored there.

 * @param result2   If non-NULL, the return ARG2 will be stored there.

 * @param result3   If non-NULL, the return ARG3 will be stored there.

 * @param result4   If non-NULL, the return ARG4 will be stored there.

 * @param result5   If non-NULL, the return ARG5 will be stored there.

 *

 * @return      Negative values represent errors returned by IPC.

 *          Otherwise the RETVAL of the answer is returned.

 */

int

ipc_call_sync_fast(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,

    ipcarg_t arg3, ipcarg_t *result1, ipcarg_t *result2, ipcarg_t *result3,

    ipcarg_t *result4, ipcarg_t *result5)

{

    ipc_call_t resdata;

    int callres;

    callres = __SYSCALL6(SYS_IPC_CALL_SYNC_FAST, phoneid, method, arg1,

        arg2, arg3, (sysarg_t) &resdata);

    if (callres)

        return callres;

    if (result1)

        *result1 = IPC_GET_ARG1(resdata);

    if (result2)

        *result2 = IPC_GET_ARG2(resdata);

    if (result3)

        *result3 = IPC_GET_ARG3(resdata);

    if (result4)

        *result4 = IPC_GET_ARG4(resdata);

    if (result5)

        *result5 = IPC_GET_ARG5(resdata);

    return IPC_GET_RETVAL(resdata);

}

/** Make a synchronous call transmitting 5 arguments of payload.

 *

 * @param phoneid   Phone handle for the call.

 * @param method    Requested method.

 * @param arg1      Service-defined payload argument.

 * @param arg2      Service-defined payload argument.

 * @param arg3      Service-defined payload argument.

 * @param arg4      Service-defined payload argument.

 * @param arg5      Service-defined payload argument.

 * @param result1   If non-NULL, storage for the first return argument.

 * @param result2   If non-NULL, storage for the second return argument.

 * @param result3   If non-NULL, storage for the third return argument.

 * @param result4   If non-NULL, storage for the fourth return argument.

 * @param result5   If non-NULL, storage for the fifth return argument.

 *

 * @return      Negative value means IPC error.

 *          Otherwise the RETVAL of the answer.

 */

int

ipc_call_sync_slow(int phoneid, ipcarg_t method, ipcarg_t arg1, ipcarg_t arg2,

    ipcarg_t arg3, ipcarg_t arg4, ipcarg_t arg5, ipcarg_t *result1,

    ipcarg_t *result2, ipcarg_t *result3, ipcarg_t *result4, ipcarg_t *result5)

{

    ipc_call_t data;

    int callres;

    IPC_SET_METHOD(data, method);

    IPC_SET_ARG1(data, arg1);

    IPC_SET_ARG2(data, arg2);

    IPC_SET_ARG3(data, arg3);

    IPC_SET_ARG4(data, arg4);

    IPC_SET_ARG5(data, arg5);

    callres = __SYSCALL3(SYS_IPC_CALL_SYNC_SLOW, phoneid, (sysarg_t) &data,

        (sysarg_t) &data);

    if (callres)

        return callres;

    if (result1)

        *result1 = IPC_GET_ARG1(data);

    if (result2)

        *result2 = IPC_GET_ARG2(data);

    if (result3)

        *result3 = IPC_GET_ARG3(data);

    if (result4)

        *result4 = IPC_GET_ARG4(data);

    if (result5)

        *result5 = IPC_GET_ARG5(data);

    return IPC_GET_RETVAL(data);

}

/** Syscall to send asynchronous message.

 *

 * @param phoneid   Phone handle for the call.

 * @param data      Call data with the request.

 *

 * @return      Hash of the call or an error code.

 */

static ipc_callid_t _ipc_call_async(int phoneid, ipc_call_t *data)

{

    return __SYSCALL2(SYS_IPC_CALL_ASYNC_SLOW, phoneid, (sysarg_t) data);

}

/** Prolog to ipc_call_async_*() functions.

 *

 * @param private   Argument for the answer/error callback.

 * @param callback  Answer/error callback.

 *

 * @return      New, partially initialized async_call structure or NULL.

 */

static inline async_call_t *ipc_prepare_async(void *private,

    ipc_async_callback_t callback)

{

    async_call_t *call;

    call = malloc(sizeof(*call));

    if (!call) {

        if (callback)

            callback(private, ENOMEM, NULL);

        return NULL;

    }

    call->callback = callback;

    call->private = private;

    return call;

}

/** Epilogue of ipc_call_async_*() functions.

 *

 * @param callid    Value returned by the SYS_IPC_CALL_ASYNC_* syscall.

 * @param phoneid   Phone handle through which the call was made.

 * @param call      async_call structure returned by ipc_prepare_async().

 * @param can_preempt   If non-zero, the current fibril can be preempted in this

 *          call.

 */

static inline void ipc_finish_async(ipc_callid_t callid, int phoneid,

    async_call_t *call, int can_preempt)

{

    if (!call) { /* Nothing to do regardless if failed or not */

        futex_up(&ipc_futex);

        return;

    }

    if (callid == IPC_CALLRET_FATAL) {

        futex_up(&ipc_futex);

        /* Call asynchronous handler with error code */

        if (call->callback)

            call->callback(call->private, ENOENT, NULL);

        free(call);

        return;

    }

    if (callid == IPC_CALLRET_TEMPORARY) {

        futex_up(&ipc_futex);

        call->u.msg.phoneid = phoneid;

        futex_down(&async_futex);

        list_append(&call->list, &queued_calls);

        if (can_preempt) {

            call->fid = fibril_get_id();

            fibril_switch(FIBRIL_TO_MANAGER);

            /* Async futex unlocked by previous call */

        } else {

            call->fid = 0;

            futex_up(&async_futex);

        }

        return;

    }

    call->u.callid = callid;

    /* Add call to the list of dispatched calls */

    list_append(&call->list, &dispatched_calls);

    futex_up(&ipc_futex);

}

/** Make a fast asynchronous call.

 *

 * This function can only handle four arguments of payload. It is, however,

 * faster than the more generic ipc_call_async_slow().

 *

 * Note that this function is a void function.

 * During normal opertation, answering this call will trigger the callback.

 * In case of fatal error, call the callback handler with the proper error code.

 * If the call cannot be temporarily made, queue it.

 *

 * @param phoneid   Phone handle for the call.

 * @param method    Requested method.

 * @param arg1      Service-defined payload argument.

 * @param arg2      Service-defined payload argument.

 * @param arg3      Service-defined payload argument.

 * @param arg4      Service-defined payload argument.

 * @param private   Argument to be passed to the answer/error callback.

 * @param callback  Answer or error callback.

 * @param can_preempt   If non-zero, the current fibril will be preempted in

 *          case the kernel temporarily refuses to accept more

 *          asynchronous calls.

 */

void ipc_call_async_fast(int phoneid, ipcarg_t method, ipcarg_t arg1,

    ipcarg_t arg2, ipcarg_t arg3, ipcarg_t arg4, void *private,

    ipc_async_callback_t callback, int can_preempt)

{

    async_call_t *call = NULL;

    ipc_callid_t callid;

    if (callback) {

        call = ipc_prepare_async(private, callback);

        if (!call)

            return;

    }

    /*

     * We need to make sure that we get callid before another thread

     * accesses the queue again.

     */

    futex_down(&ipc_futex);

    callid = __SYSCALL6(SYS_IPC_CALL_ASYNC_FAST, phoneid, method, arg1,

        arg2, arg3, arg4);

    if (callid == IPC_CALLRET_TEMPORARY) {

        if (!call) {

            call = ipc_prepare_async(private, callback);

            if (!call)

                return;

        }

        IPC_SET_METHOD(call->u.msg.data, method);

        IPC_SET_ARG1(call->u.msg.data, arg1);

        IPC_SET_ARG2(call->u.msg.data, arg2);

        IPC_SET_ARG3(call->u.msg.data, arg3);

        IPC_SET_ARG4(call->u.msg.data, arg4);

        /*

         * To achieve deterministic behavior, we always zero out the

         * arguments that are beyond the limits of the fast version.

         */

        IPC_SET_ARG5(call->u.msg.data, 0);

    }

    ipc_finish_async(callid, phoneid, call, can_preempt);

}

/** Make an asynchronous call transmitting the entire payload.

 *

 * Note that this function is a void function.

 * During normal opertation, answering this call will trigger the callback.

 * In case of fatal error, call the callback handler with the proper error code.

 * If the call cannot be temporarily made, queue it.

 *

 * @param phoneid   Phone handle for the call.

 * @param method    Requested method.

 * @param arg1      Service-defined payload argument.

 * @param arg2      Service-defined payload argument.

 * @param arg3      Service-defined payload argument.

 * @param arg4      Service-defined payload argument.

 * @param arg5      Service-defined payload argument.

 * @param private   Argument to be passed to the answer/error callback.

 * @param callback  Answer or error callback.

 * @param can_preempt   If non-zero, the current fibril will be preempted in

 *          case the kernel temporarily refuses to accept more

 *          asynchronous calls.

 *

 */

void ipc_call_async_slow(int phoneid, ipcarg_t method, ipcarg_t arg1,

    ipcarg_t arg2, ipcarg_t arg3, ipcarg_t arg4, ipcarg_t arg5, void *private,

    ipc_async_callback_t callback, int can_preempt)

{

    async_call_t *call;

    ipc_callid_t callid;

    call = ipc_prepare_async(private, callback);

    if (!call)

        return;

    IPC_SET_METHOD(call->u.msg.data, method);

    IPC_SET_ARG1(call->u.msg.data, arg1);

    IPC_SET_ARG2(call->u.msg.data, arg2);

    IPC_SET_ARG3(call->u.msg.data, arg3);

    IPC_SET_ARG4(call->u.msg.data, arg4);

    IPC_SET_ARG5(call->u.msg.data, arg5);

    /*

     * We need to make sure that we get callid before another thread

     * accesses the queue again.

     */

    futex_down(&ipc_futex);

    callid = _ipc_call_async(phoneid, &call->u.msg.data);

    ipc_finish_async(callid, phoneid, call, can_preempt);

}

/** Answer a received call - fast version.

 *

 * The fast answer makes use of passing retval and first four arguments in

 * registers. If you need to return more, use the ipc_answer_slow() instead.

 *

 * @param callid    Hash of the call being answered.

 * @param retval    Return value.

 * @param arg1      First return argument.

 * @param arg2      Second return argument.

 * @param arg3      Third return argument.

 * @param arg4      Fourth return argument.

 *

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

 */

ipcarg_t ipc_answer_fast(ipc_callid_t callid, ipcarg_t retval, ipcarg_t arg1,

    ipcarg_t arg2, ipcarg_t arg3, ipcarg_t arg4)

{

    return __SYSCALL6(SYS_IPC_ANSWER_FAST, callid, retval, arg1, arg2, arg3,

        arg4);

}

/** Answer a received call - slow full version.

 *

 * @param callid    Hash of the call being answered.

 * @param retval    Return value.

 * @param arg1      First return argument.

 * @param arg2      Second return argument.

 * @param arg3      Third return argument.

 * @param arg4      Fourth return argument.

 * @param arg5      Fifth return argument.

 *

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

 */

ipcarg_t ipc_answer_slow(ipc_callid_t callid, ipcarg_t retval, ipcarg_t arg1,

    ipcarg_t arg2, ipcarg_t arg3, ipcarg_t arg4, ipcarg_t arg5)

{

    ipc_call_t data;

    IPC_SET_RETVAL(data, retval);

    IPC_SET_ARG1(data, arg1);

    IPC_SET_ARG2(data, arg2);

    IPC_SET_ARG3(data, arg3);

    IPC_SET_ARG4(data, arg4);

    IPC_SET_ARG5(data, arg5);

    return __SYSCALL2(SYS_IPC_ANSWER_SLOW, callid, (sysarg_t) &data);

}

/** Try to dispatch queued calls from the async queue. */

static void try_dispatch_queued_calls(void)

{

    async_call_t *call;

    ipc_callid_t callid;

    /** @todo

     * Integrate intelligently ipc_futex, so that it is locked during

     * ipc_call_async_*(), until it is added to dispatched_calls.

     */

    futex_down(&async_futex);

    while (!list_empty(&queued_calls)) {

        call = list_get_instance(queued_calls.next, async_call_t, list);

        callid = _ipc_call_async(call->u.msg.phoneid,

            &call->u.msg.data);

        if (callid == IPC_CALLRET_TEMPORARY) {

            break;

        }

        list_remove(&call->list);

        futex_up(&async_futex);

        if (call->fid)

            fibril_add_ready(call->fid);

        if (callid == IPC_CALLRET_FATAL) {

            if (call->callback)

                call->callback(call->private, ENOENT, NULL);

            free(call);

        } else {

            call->u.callid = callid;

            futex_down(&ipc_futex);

            list_append(&call->list, &dispatched_calls);

            futex_up(&ipc_futex);

        }

        futex_down(&async_futex);

    }

    futex_up(&async_futex);

}

/** Handle a received answer.

 *

 * Find the hash of the answer and call the answer callback.

 *

 * @todo Make it use hash table.

 *

 * @param callid    Hash of the received answer.

 *          The answer has the same hash as the request OR'ed with

 *          the IPC_CALLID_ANSWERED bit.

 * @param data      Call data of the answer.

 */

static void handle_answer(ipc_callid_t callid, ipc_call_t *data)

{

    link_t *item;

    async_call_t *call;

    callid &= ~IPC_CALLID_ANSWERED;

    futex_down(&ipc_futex);

    for (item = dispatched_calls.next; item != &dispatched_calls;

        item = item->next) {

        call = list_get_instance(item, async_call_t, list);

        if (call->u.callid == callid) {

            list_remove(&call->list);

            futex_up(&ipc_futex);

            if (call->callback)

                call->callback(call->private,

                    IPC_GET_RETVAL(*data), data);

            free(call);

            return;

        }

    }

    futex_up(&ipc_futex);

}

/** Wait for a first call to come.

 *

 * @param call      Storage where the incoming call data will be stored.

 * @param usec      Timeout in microseconds

 * @param flags     Flags passed to SYS_IPC_WAIT (blocking, nonblocking).

 *

 * @return      Hash of the call. Note that certain bits have special

 *          meaning. IPC_CALLID_ANSWERED will be set in an answer

 *          and IPC_CALLID_NOTIFICATION is used for notifications.

 *         

 */

ipc_callid_t ipc_wait_cycle(ipc_call_t *call, uint32_t usec, int flags)

{

    ipc_callid_t callid;

    callid = __SYSCALL3(SYS_IPC_WAIT, (sysarg_t) call, usec, flags);

    /* Handle received answers */

    if (callid & IPC_CALLID_ANSWERED) {

        handle_answer(callid, call);

        try_dispatch_queued_calls();

    }

    return callid;

}

/** Wait some time for an IPC call.

 *

 * The call will return after an answer is received.

 *

 * @param call      Storage where the incoming call data will be stored.

 * @param usec      Timeout in microseconds.

 *

 * @return      Hash of the answer.

 */

ipc_callid_t ipc_wait_for_call_timeout(ipc_call_t *call, uint32_t usec)

{

    ipc_callid_t callid;

    do {

        callid = ipc_wait_cycle(call, usec, SYNCH_FLAGS_NONE);

    } while (callid & IPC_CALLID_ANSWERED);

    return callid;

}

/** Check if there is an IPC call waiting to be picked up.

 *

 * @param call      Storage where the incoming call will be stored.

 * @return      Hash of the answer.

 */

ipc_callid_t ipc_trywait_for_call(ipc_call_t *call)

{

    ipc_callid_t callid;

    do {

        callid = ipc_wait_cycle(call, SYNCH_NO_TIMEOUT,

            SYNCH_FLAGS_NON_BLOCKING);

    } while (callid & IPC_CALLID_ANSWERED);

    return callid;

}

/** Ask destination to do a callback connection.

 *

 * @param phoneid   Phone handle used for contacting the other side.

 * @param arg1      Service-defined argument.

 * @param arg2      Service-defined argument.

 * @param arg3      Service-defined argument.

 * @param phonehash Storage where the library will store an opaque

 *          identifier of the phone that will be used for incoming

 *          calls. This identifier can be used for connection

 *          tracking.

 *

 * @return      Zero on success or a negative error code.

 */

int ipc_connect_to_me(int phoneid, int arg1, int arg2, int arg3,

    ipcarg_t *phonehash)

{

    return ipc_call_sync_3_5(phoneid, IPC_M_CONNECT_TO_ME, arg1, arg2,

        arg3, NULL, NULL, NULL, NULL, phonehash);

}

/** Ask through phone for a new connection to some service.

 *

 * @param phoneid   Phone handle used for contacting the other side.

 * @param arg1      User defined argument.

 * @param arg2      User defined argument.

 * @param arg3      User defined argument.

 *

 * @return      New phone handle on success or a negative error code.

 */

int ipc_connect_me_to(int phoneid, int arg1, int arg2, int arg3)

{

    ipcarg_t newphid;

    int res;

    res = ipc_call_sync_3_5(phoneid, IPC_M_CONNECT_ME_TO, arg1, arg2, arg3,

        NULL, NULL, NULL, NULL, &newphid);

    if (res)

        return res;

    return newphid;

}

/** Hang up a phone.

 *

 * @param phoneid   Handle of the phone to be hung up.

 *

 * @return      Zero on success or a negative error code.

 */

int ipc_hangup(int phoneid)

{

    return __SYSCALL1(SYS_IPC_HANGUP, phoneid);

}

/** Register IRQ notification.

 *

 * @param inr       IRQ number.

 * @param devno     Device number of the device generating inr.

 * @param method    Use this method for notifying me.

 * @param ucode     Top-half pseudocode handler.

 *

 * @return      Value returned by the kernel.

 */

int ipc_register_irq(int inr, int devno, int method, irq_code_t *ucode)

{

    return __SYSCALL4(SYS_IPC_REGISTER_IRQ, inr, devno, method,

        (sysarg_t) ucode);

}

/** Unregister IRQ notification.

 *

 * @param inr       IRQ number.

 * @param devno     Device number of the device generating inr.

 *

 * @return      Value returned by the kernel.

 */

int ipc_unregister_irq(int inr, int devno)

{

    return __SYSCALL2(SYS_IPC_UNREGISTER_IRQ, inr, devno);

}

/** Forward a received call to another destination.

 *

 * @param callid    Hash of the call to forward.

 * @param phoneid   Phone handle to use for forwarding.

 * @param method    New method for the forwarded call.

 * @param arg1      New value of the first argument for the forwarded call.

 * @param arg2      New value of the second argument for the forwarded call.

 * @param mode      Flags specifying mode of the forward operation.

 *

 * @return      Zero on success or an error code.

 *

 * For non-system methods, the old method, arg1 and arg2 are rewritten by the

 * new values. For system methods, the new method, arg1 and arg2 are written

 * to the old arg1, arg2 and arg3, respectivelly. Calls with immutable

 * methods are forwarded verbatim.

 */

int ipc_forward_fast(ipc_callid_t callid, int phoneid, int method,

    ipcarg_t arg1, ipcarg_t arg2, int mode)

{

    return __SYSCALL6(SYS_IPC_FORWARD_FAST, callid, phoneid, method, arg1,

        arg2, mode);

}

/** Wrapper for making IPC_M_DATA_SEND calls.

 *

 * @param phoneid   Phone that will be used to contact the receiving side.

 * @param src       Address of the beginning of the source buffer.

 * @param size      Size of the source buffer.

 *

 * @return      Zero on success or a negative error code from errno.h.

 */

int ipc_data_send(int phoneid, void *src, size_t size)

{

    return ipc_call_sync_3_0(phoneid, IPC_M_DATA_SEND, 0, (ipcarg_t) src,

        (ipcarg_t) size);

}

/** Wrapper for receiving the IPC_M_DATA_SEND calls.

 *

 * This wrapper only makes it more comfortable to receive IPC_M_DATA_SEND calls

 * so that the user doesn't have to remember the meaning of each IPC argument.

 *

 * So far, this wrapper is to be used from within a connection fibril.

 *

 * @param callid    Storage where the hash of the IPC_M_DATA_SEND call will

 *          be stored.

 * @param dst       Storage where the suggested destination address will

 *          be stored. May be NULL.

 * @param size      Storage where the suggested size will be stored. May be

 *          NULL

 *

 * @return      Non-zero on success, zero on failure.

 */

int ipc_data_receive(ipc_callid_t *callid, void **dst, size_t *size)

{

    ipc_call_t data;

    assert(callid);

    *callid = async_get_call(&data);

    if (IPC_GET_METHOD(data) != IPC_M_DATA_SEND)

        return 0;

    if (dst)

        *dst = (void *) IPC_GET_ARG1(data);

    if (size)

        *size = (size_t) IPC_GET_ARG3(data);

    return 1;

}

/** Wrapper for answering the IPC_M_DATA_SEND calls.

 *

 * This wrapper only makes it more comfortable to answer IPC_M_DATA_SEND calls

 * so that the user doesn't have to remember the meaning of each IPC argument.

 *

 * @param callid    Hash of the IPC_M_DATA_SEND call to answer.

 * @param dst       Final destination address for the IPC_M_DATA_SEND call.

 * @param size      Final size for the IPC_M_DATA_SEND call.

 *

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

 */

ipcarg_t ipc_data_deliver(ipc_callid_t callid, void *dst, size_t size)

{

    return ipc_answer_3(callid, EOK, (ipcarg_t) dst, 0, (ipcarg_t) size);

}

/** @}

 */