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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 genericipc
 * @{
 */

/** @file
 */


#include <arch.h>
#include <proc/task.h>
#include <proc/thread.h>
#include <errno.h>
#include <memstr.h>
#include <debug.h>
#include <ipc/ipc.h>
#include <ipc/sysipc.h>
#include <ipc/irq.h>
#include <ipc/ipcrsc.h>
#include <arch/interrupt.h>
#include <print.h>
#include <syscall/copy.h>
#include <security/cap.h>
#include <mm/as.h>

#define GET_CHECK_PHONE(phone,phoneid,err) { \
      if (phoneid > IPC_MAX_PHONES) { err; } \
      phone = &TASK->phones[phoneid]; \
}


#define STRUCT_TO_USPACE(dst,src) copy_to_uspace(dst,src,sizeof(*(src)))

/** Return true if the method is a system method */
static inline int is_system_method(__native method)
{
    if (method <= IPC_M_LAST_SYSTEM)
        return 1;
    return 0;
}

/** Return true if the message with this method is forwardable
 *
 * - some system messages may be forwarded, for some of them
 *   it is useless
 */

static inline int is_forwardable(__native method)
{
    if (method == IPC_M_PHONE_HUNGUP || method == IPC_M_AS_AREA_SEND \
        || method == IPC_M_AS_AREA_RECV)
        return 0; /* This message is meant only for the receiver */
    return 1;
}

/****************************************************/
/* Functions that preprocess answer before sending
 * it to the recepient
 */


/** Return true if the caller (ipc_answer) should save
 * the old call contents for answer_preprocess
 */

static inline int answer_need_old(call_t *call)
{
    if (IPC_GET_METHOD(call->data) == IPC_M_CONNECT_TO_ME)
        return 1;
    if (IPC_GET_METHOD(call->data) == IPC_M_CONNECT_ME_TO)
        return 1;
    if (IPC_GET_METHOD(call->data) == IPC_M_AS_AREA_SEND)
        return 1;
    if (IPC_GET_METHOD(call->data) == IPC_M_AS_AREA_RECV)
        return 1;
    return 0;
}

/** Interpret process answer as control information
 *
 * This function is called directly after sys_ipc_answer
 */

static inline int answer_preprocess(call_t *answer, ipc_data_t *olddata)
{
    int phoneid;

    if (IPC_GET_RETVAL(answer->data) == EHANGUP) {
        /* In case of forward, hangup the forwared phone,
         * not the originator
         */

        spinlock_lock(&answer->data.phone->lock);
        spinlock_lock(&TASK->answerbox.lock);
        if (answer->data.phone->state == IPC_PHONE_CONNECTED) {
            list_remove(&answer->data.phone->link);
            answer->data.phone->state = IPC_PHONE_SLAMMED;
        }
        spinlock_unlock(&TASK->answerbox.lock);
        spinlock_unlock(&answer->data.phone->lock);
    }

    if (!olddata)
        return 0;

    if (IPC_GET_METHOD(*olddata) == IPC_M_CONNECT_TO_ME) {
        phoneid = IPC_GET_ARG3(*olddata);
        if (IPC_GET_RETVAL(answer->data)) {
            /* The connection was not accepted */
            phone_dealloc(phoneid);
        } else {
            /* The connection was accepted */
            phone_connect(phoneid,&answer->sender->answerbox);
            /* Set 'phone identification' as arg3 of response */
            IPC_SET_ARG3(answer->data, (__native)&TASK->phones[phoneid]);
        }
    } else if (IPC_GET_METHOD(*olddata) == IPC_M_CONNECT_ME_TO) {
        /* If the users accepted call, connect */
        if (!IPC_GET_RETVAL(answer->data)) {
            ipc_phone_connect((phone_t *)IPC_GET_ARG3(*olddata),
                      &TASK->answerbox);
        }
    } else if (IPC_GET_METHOD(*olddata) == IPC_M_AS_AREA_SEND) {
        if (!IPC_GET_RETVAL(answer->data)) { /* Accepted, handle as_area receipt */
            ipl_t ipl;
            int rc;
            as_t *as;
           
            ipl = interrupts_disable();
            spinlock_lock(&answer->sender->lock);
            as = answer->sender->as;
            spinlock_unlock(&answer->sender->lock);
            interrupts_restore(ipl);
           
            rc = as_area_share(as, IPC_GET_ARG1(*olddata), IPC_GET_ARG2(*olddata),
                       AS, IPC_GET_ARG1(answer->data), IPC_GET_ARG3(*olddata));
            IPC_SET_RETVAL(answer->data, rc);
            return rc;
        }
    } else if (IPC_GET_METHOD(*olddata) == IPC_M_AS_AREA_RECV) {
        if (!IPC_GET_RETVAL(answer->data)) {
            ipl_t ipl;
            as_t *as;
            int rc;
           
            ipl = interrupts_disable();
            spinlock_lock(&answer->sender->lock);
            as = answer->sender->as;
            spinlock_unlock(&answer->sender->lock);
            interrupts_restore(ipl);
           
            rc = as_area_share(AS, IPC_GET_ARG1(answer->data), IPC_GET_ARG2(*olddata),
                       as, IPC_GET_ARG1(*olddata), IPC_GET_ARG2(answer->data));
            IPC_SET_RETVAL(answer->data, rc);
        }
    }
    return 0;
}

/** Called before the request is sent
 *
 * @return 0 - no error, -1 - report error to user
 */

static int request_preprocess(call_t *call)
{
    int newphid;
    size_t size;

    switch (IPC_GET_METHOD(call->data)) {
    case IPC_M_CONNECT_ME_TO:
        newphid = phone_alloc();
        if (newphid < 0)
            return ELIMIT;
        /* Set arg3 for server */
        IPC_SET_ARG3(call->data, (__native)&TASK->phones[newphid]);
        call->flags |= IPC_CALL_CONN_ME_TO;
        call->private = newphid;
        break;
    case IPC_M_AS_AREA_SEND:
        size = as_get_size(IPC_GET_ARG1(call->data));
        if (!size) {
            return EPERM;
        }
        IPC_SET_ARG2(call->data, size);
        break;
    default:
        break;
    }
    return 0;
}

/****************************************************/
/* Functions called to process received call/answer
 * before passing to uspace
 */


/** Do basic kernel processing of received call answer */
static void process_answer(call_t *call)
{
    if (IPC_GET_RETVAL(call->data) == EHANGUP && \
        call->flags & IPC_CALL_FORWARDED)
        IPC_SET_RETVAL(call->data, EFORWARD);

    if (call->flags & IPC_CALL_CONN_ME_TO) {
        if (IPC_GET_RETVAL(call->data))
            phone_dealloc(call->private);
        else
            IPC_SET_ARG3(call->data, call->private);
    }
}

/** Do basic kernel processing of received call request
 *
 * @return 0 - the call should be passed to userspace, 1 - ignore call
 */

static int process_request(answerbox_t *box,call_t *call)
{
    int phoneid;

    if (IPC_GET_METHOD(call->data) == IPC_M_CONNECT_TO_ME) {
        phoneid = phone_alloc();
        if (phoneid < 0) { /* Failed to allocate phone */
            IPC_SET_RETVAL(call->data, ELIMIT);
            ipc_answer(box,call);
            return -1;
        }
        IPC_SET_ARG3(call->data, phoneid);
    }
    return 0;
}

/** Send a call over IPC, wait for reply, return to user
 *
 * @return Call identification, returns -1 on fatal error,
           -2 on 'Too many async request, handle answers first
 */

__native sys_ipc_call_sync_fast(__native phoneid, __native method,
                __native arg1, ipc_data_t *data)
{
    call_t call;
    phone_t *phone;
    int res;

    GET_CHECK_PHONE(phone, phoneid, return ENOENT);

    ipc_call_static_init(&call);
    IPC_SET_METHOD(call.data, method);
    IPC_SET_ARG1(call.data, arg1);

    if (!(res=request_preprocess(&call))) {
        ipc_call_sync(phone, &call);
        process_answer(&call);
    } else
        IPC_SET_RETVAL(call.data, res);
    STRUCT_TO_USPACE(&data->args, &call.data.args);

    return 0;
}

/** Synchronous IPC call allowing to send whole message */
__native sys_ipc_call_sync(__native phoneid, ipc_data_t *question,
               ipc_data_t *reply)
{
    call_t call;
    phone_t *phone;
    int res;
    int rc;

    ipc_call_static_init(&call);
    rc = copy_from_uspace(&call.data.args, &question->args, sizeof(call.data.args));
    if (rc != 0)
        return (__native) rc;

    GET_CHECK_PHONE(phone, phoneid, return ENOENT);

    if (!(res=request_preprocess(&call))) {
        ipc_call_sync(phone, &call);
        process_answer(&call);
    } else
        IPC_SET_RETVAL(call.data, res);

    rc = STRUCT_TO_USPACE(&reply->args, &call.data.args);
    if (rc != 0)
        return rc;

    return 0;
}

/** Check that the task did not exceed allowed limit
 *
 * @return 0 - Limit OK,   -1 - limit exceeded
 */

static int check_call_limit(void)
{
    if (atomic_preinc(&TASK->active_calls) > IPC_MAX_ASYNC_CALLS) {
        atomic_dec(&TASK->active_calls);
        return -1;
    }
    return 0;
}

/** Send an asynchronous call over ipc
 *
 * @return Call identification, returns -1 on fatal error,
           -2 on 'Too many async request, handle answers first
 */

__native sys_ipc_call_async_fast(__native phoneid, __native method,
                 __native arg1, __native arg2)
{
    call_t *call;
    phone_t *phone;
    int res;

    if (check_call_limit())
        return IPC_CALLRET_TEMPORARY;

    GET_CHECK_PHONE(phone, phoneid, return IPC_CALLRET_FATAL);

    call = ipc_call_alloc(0);
    IPC_SET_METHOD(call->data, method);
    IPC_SET_ARG1(call->data, arg1);
    IPC_SET_ARG2(call->data, arg2);
    IPC_SET_ARG3(call->data, 0);

    if (!(res=request_preprocess(call)))
        ipc_call(phone, call);
    else
        ipc_backsend_err(phone, call, res);

    return (__native) call;
}

/** Synchronous IPC call allowing to send whole message
 *
 * @return The same as sys_ipc_call_async
 */

__native sys_ipc_call_async(__native phoneid, ipc_data_t *data)
{
    call_t *call;
    phone_t *phone;
    int res;
    int rc;

    if (check_call_limit())
        return IPC_CALLRET_TEMPORARY;

    GET_CHECK_PHONE(phone, phoneid, return IPC_CALLRET_FATAL);

    call = ipc_call_alloc(0);
    rc = copy_from_uspace(&call->data.args, &data->args, sizeof(call->data.args));
    if (rc != 0) {
        ipc_call_free(call);
        return (__native) rc;
    }
    if (!(res=request_preprocess(call)))
        ipc_call(phone, call);
    else
        ipc_backsend_err(phone, call, res);

    return (__native) call;
}

/** Forward received call to another destination
 *
 * The arg1 and arg2 are changed in the forwarded message
 *
 * Warning: If implementing non-fast version, make sure that
 *          arg3 is not rewritten for certain system IPC
 */

__native sys_ipc_forward_fast(__native callid, __native phoneid,
                  __native method, __native arg1)
{
    call_t *call;
    phone_t *phone;

    call = get_call(callid);
    if (!call)
        return ENOENT;

    call->flags |= IPC_CALL_FORWARDED;

    GET_CHECK_PHONE(phone, phoneid, {
        IPC_SET_RETVAL(call->data, EFORWARD);
        ipc_answer(&TASK->answerbox, call);
        return ENOENT;
    });    

    if (!is_forwardable(IPC_GET_METHOD(call->data))) {
        IPC_SET_RETVAL(call->data, EFORWARD);
        ipc_answer(&TASK->answerbox, call);
        return EPERM;
    }

    /* Userspace is not allowed to change method of system methods
     * on forward, allow changing ARG1 and ARG2 by means of method and arg1
     */

    if (is_system_method(IPC_GET_METHOD(call->data))) {
        if (IPC_GET_METHOD(call->data) == IPC_M_CONNECT_TO_ME)
            phone_dealloc(IPC_GET_ARG3(call->data));

        IPC_SET_ARG1(call->data, method);
        IPC_SET_ARG2(call->data, arg1);
    } else {
        IPC_SET_METHOD(call->data, method);
        IPC_SET_ARG1(call->data, arg1);
    }

    return ipc_forward(call, phone, &TASK->answerbox);
}

/** Send IPC answer */
__native sys_ipc_answer_fast(__native callid, __native retval,
                 __native arg1, __native arg2)
{
    call_t *call;
    ipc_data_t saved_data;
    int saveddata = 0;
    int rc;

    /* Do not answer notification callids */
    if (callid & IPC_CALLID_NOTIFICATION)
        return 0;

    call = get_call(callid);
    if (!call)
        return ENOENT;

    if (answer_need_old(call)) {
        memcpy(&saved_data, &call->data, sizeof(call->data));
        saveddata = 1;
    }

    IPC_SET_RETVAL(call->data, retval);
    IPC_SET_ARG1(call->data, arg1);
    IPC_SET_ARG2(call->data, arg2);
    rc = answer_preprocess(call, saveddata ? &saved_data : NULL);

    ipc_answer(&TASK->answerbox, call);
    return rc;
}

/** Send IPC answer */
__native sys_ipc_answer(__native callid, ipc_data_t *data)
{
    call_t *call;
    ipc_data_t saved_data;
    int saveddata = 0;
    int rc;

    /* Do not answer notification callids */
    if (callid & IPC_CALLID_NOTIFICATION)
        return 0;

    call = get_call(callid);
    if (!call)
        return ENOENT;

    if (answer_need_old(call)) {
        memcpy(&saved_data, &call->data, sizeof(call->data));
        saveddata = 1;
    }
    rc = copy_from_uspace(&call->data.args, &data->args,
             sizeof(call->data.args));
    if (rc != 0)
        return rc;

    rc = answer_preprocess(call, saveddata ? &saved_data : NULL);
   
    ipc_answer(&TASK->answerbox, call);

    return rc;
}

/** Hang up the phone
 *
 */

__native sys_ipc_hangup(int phoneid)
{
    phone_t *phone;

    GET_CHECK_PHONE(phone, phoneid, return ENOENT);

    if (ipc_phone_hangup(phone))
        return -1;

    return 0;
}

/** Wait for incoming ipc call or answer
 *
 * @param calldata Pointer to buffer where the call/answer data is stored
 * @param usec Timeout. See waitq_sleep_timeout() for explanation.
 * @param flags Select mode of sleep operation. See waitq_sleep_timeout() for explanation.
 *
 * @return Callid, if callid & 1, then the call is answer
 */

__native sys_ipc_wait_for_call(ipc_data_t *calldata, __u32 usec, int flags)
{
    call_t *call;

restart:   
    call = ipc_wait_for_call(&TASK->answerbox, usec, flags | SYNCH_FLAGS_INTERRUPTIBLE);
    if (!call)
        return 0;

    if (call->flags & IPC_CALL_NOTIF) {
        ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));

        /* Set in_phone_hash to the interrupt counter */
        call->data.phone = (void *)call->private;
       
        STRUCT_TO_USPACE(calldata, &call->data);

        ipc_call_free(call);
       
        return ((__native)call) | IPC_CALLID_NOTIFICATION;
    }

    if (call->flags & IPC_CALL_ANSWERED) {
        process_answer(call);

        ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));

        atomic_dec(&TASK->active_calls);

        if (call->flags & IPC_CALL_DISCARD_ANSWER) {
            ipc_call_free(call);
            goto restart;
        }

        STRUCT_TO_USPACE(&calldata->args, &call->data.args);
        ipc_call_free(call);

        return ((__native)call) | IPC_CALLID_ANSWERED;
    }

    if (process_request(&TASK->answerbox, call))
        goto restart;

    /* Include phone address('id') of the caller in the request,
     * copy whole call->data, not only call->data.args */

    if (STRUCT_TO_USPACE(calldata, &call->data)) {
        return 0;
    }
    return (__native)call;
}

/** Connect irq handler to task */
__native sys_ipc_register_irq(int irq, irq_code_t *ucode)
{
    if (!(cap_get(TASK) & CAP_IRQ_REG))
        return EPERM;

    if (irq >= IRQ_COUNT || irq <= -IPC_IRQ_RESERVED_VIRTUAL)
        return (__native) ELIMIT;
   
    irq_ipc_bind_arch(irq);

    return ipc_irq_register(&TASK->answerbox, irq, ucode);
}

/* Disconnect irq handler from task */
__native sys_ipc_unregister_irq(int irq)
{
    if (!(cap_get(TASK) & CAP_IRQ_REG))
        return EPERM;

    if (irq >= IRQ_COUNT || irq <= -IPC_IRQ_RESERVED_VIRTUAL)
        return (__native) ELIMIT;

    ipc_irq_unregister(&TASK->answerbox, irq);

    return 0;
}

/** @}
 */