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/*
 * Copyright (C) 2005 Martin Decky
 * 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.
 */

#include <syscall/syscall.h>
#include <proc/thread.h>
#include <mm/as.h>
#include <print.h>
#include <putchar.h>
#include <ipc/ipc.h>
#include <errno.h>
#include <proc/task.h>
#include <arch.h>
#include <debug.h>

static __native sys_ctl(void) {
    printf("Thread finished\n");
    thread_exit();
    /* Unreachable */
    return 0;
}

static __native sys_io(int fd, const void * buf, size_t count) {
    
    // TODO: buf sanity checks and a lot of other stuff ...

    size_t i;
    
    for (i = 0; i < count; i++)
        putchar(((char *) buf)[i]);
    
    return count;
}

static phone_t * get_phone(__native phoneid)
{
    phone_t *phone;

    if (phoneid >= IPC_MAX_PHONES)
        return NULL;

    phone = &TASK->phones[phoneid];
    if (!phone->callee)
        return NULL;
    return phone;
}

/** 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
 */
static __native sys_ipc_call_sync_fast(__native phoneid, __native method, 
                       __native arg1, __native *data)
{
    call_t call;
    phone_t *phone;
    /* Special answerbox for synchronous messages */

    phone = get_phone(phoneid);
    if (!phone)
        return IPC_CALLRET_FATAL;

    ipc_call_init(&call);
    IPC_SET_METHOD(call.data, method);
    IPC_SET_ARG1(call.data, arg1);
    
    ipc_call_sync(phone, &call);

    copy_to_uspace(data, &call.data, sizeof(call.data));

    return 0;
}

/** Synchronous IPC call allowing to send whole message */
static __native sys_ipc_call_sync(__native phoneid, __native *question, 
                  __native *reply)
{
    call_t call;
    phone_t *phone;
    /* Special answerbox for synchronous messages */

    phone = get_phone(phoneid);
    if (!phone)
        return IPC_CALLRET_FATAL;

    ipc_call_init(&call);
    copy_from_uspace(&call.data, question, sizeof(call.data));
    
    ipc_call_sync(phone, &call);

    copy_to_uspace(reply, &call.data, sizeof(call.data));

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

    phone = get_phone(phoneid);
    if (!phone)
        return IPC_CALLRET_FATAL;

    if (check_call_limit())
        return IPC_CALLRET_TEMPORARY;

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

    ipc_call(phone, call);

    return (__native) call;
}

/** Synchronous IPC call allowing to send whole message
 *
 * @return The same as sys_ipc_call_async
 */
static __native sys_ipc_call_async(__native phoneid, __native *data)
{
    call_t *call;
    phone_t *phone;

    phone = get_phone(phoneid);
    if (!phone)
        return IPC_CALLRET_FATAL;

    if (check_call_limit())
        return IPC_CALLRET_TEMPORARY;

    call = ipc_call_alloc();
    copy_from_uspace(&call->data, data, sizeof(call->data));
    
    ipc_call(phone, call);

    return (__native) call;
}


/** Send IPC answer */
static __native sys_ipc_answer_fast(__native callid, __native retval, 
                    __native arg1, __native arg2)
{
    call_t *call;

    /* Check that the user is not sending us answer callid */
    ASSERT(! (callid & 1));
    /* TODO: Check that the callid is in the dispatch table */
    call = (call_t *) callid;

    IPC_SET_RETVAL(call->data, retval);
    IPC_SET_ARG1(call->data, arg1);
    IPC_SET_ARG2(call->data, arg2);

    ipc_answer(&TASK->answerbox, call);
    return 0;
}

/** Send IPC answer */
static __native sys_ipc_answer(__native callid, __native *data)
{
    call_t *call;

    /* Check that the user is not sending us answer callid */
    ASSERT(! (callid & 1));
    /* TODO: Check that the callid is in the dispatch table */
    call = (call_t *) callid;
    copy_from_uspace(&call->data, data, sizeof(call->data));
    ipc_answer(&TASK->answerbox, call);

    return 0;
}

/** Wait for incoming ipc call or answer
 *
 * @param result 
 * @param flags
 * @return Callid, if callid & 1, then the call is answer
 */
static __native sys_ipc_wait_for_call(__native *calldata, task_id_t *taskid,
                      __native flags)
{
    call_t *call;
    
    call = ipc_wait_for_call(&TASK->answerbox, flags);

    copy_to_uspace(calldata, &call->data, sizeof(call->data));

    if (call->flags & IPC_CALL_ANSWERED) {
        ASSERT(! (call->flags & IPC_CALL_STATIC_ALLOC));
        ipc_call_free(call);
        atomic_dec(&TASK->active_calls);
        return ((__native)call) | IPC_CALLID_ANSWERED;
    }
    copy_to_uspace(taskid, (void *)&TASK->taskid, sizeof(TASK->taskid));
    return (__native)call;
}

static __native sys_mremap(void *address, size_t size, unsigned long flags)
{
    return as_remap(AS, (__address) address, size, 0);
}

syshandler_t syscall_table[SYSCALL_END] = {
    sys_ctl,
    sys_io,
    sys_mremap,
    sys_ipc_call_sync_fast,
    sys_ipc_call_sync,
    sys_ipc_call_async_fast,
    sys_ipc_call_async,
    sys_ipc_answer_fast,
    sys_ipc_answer,
    sys_ipc_wait_for_call
};