source: mainline/generic/src/syscall/syscall.c@ 5f62ef9

/*
 * 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 *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);
        copy_from_uspace(&call.data, data, sizeof(call.data));
        
        ipc_call_sync(phone, &call);

        copy_to_uspace(data, &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_inc_post(&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(__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;
}

/** 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, __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;
        }
        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,
        sys_ipc_wait_for_call
};