source: mainline/libipc/generic/ipc.c@ fa3561f

/*
 * 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.
 */ 

#include <ipc.h>
#include <libc.h>
#include <malloc.h>
#include <errno.h>
#include <list.h>
#include <stdio.h>
#include <unistd.h>

/** Structure used for keeping track of sent async msgs 
 * and queing unsent msgs
 *
 */
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;
} async_call_t;

LIST_INITIALIZE(dispatched_calls);
LIST_INITIALIZE(queued_calls);

int ipc_call_sync(int phoneid, ipcarg_t method, ipcarg_t arg1, 
                  ipcarg_t *result)
{
        ipc_call_t resdata;
        int callres;
        
        callres = __SYSCALL4(SYS_IPC_CALL_SYNC_FAST, phoneid, method, arg1,
                             (sysarg_t)&resdata);
        if (callres)
                return callres;
        if (result)
                *result = IPC_GET_ARG1(resdata);
        return IPC_GET_RETVAL(resdata);
}

int ipc_call_sync_3(int phoneid, ipcarg_t method, ipcarg_t arg1,
                    ipcarg_t arg2, ipcarg_t arg3,
                    ipcarg_t *result1, ipcarg_t *result2, ipcarg_t *result3)
{
        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);

        callres = __SYSCALL3(SYS_IPC_CALL_SYNC, 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);
        return IPC_GET_RETVAL(data);
}

/** Syscall to send asynchronous message */
static  ipc_callid_t _ipc_call_async(int phoneid, ipc_call_t *data)
{
        return __SYSCALL2(SYS_IPC_CALL_ASYNC, phoneid, (sysarg_t)data);
}

/** Send asynchronous message
 *
 * - if fatal error, call callback handler with proper error code
 * - if message cannot be temporarily sent, add to queue
 */
void ipc_call_async_2(int phoneid, ipcarg_t method, ipcarg_t arg1,
                      ipcarg_t arg2, void *private,
                      ipc_async_callback_t callback)
{
        async_call_t *call;
        ipc_callid_t callid;

        call = malloc(sizeof(*call));
        if (!call) {
                callback(private, ENOMEM, NULL);
                return;
        }
                
        callid = __SYSCALL4(SYS_IPC_CALL_ASYNC_FAST, phoneid, method, arg1, arg2);
        if (callid == IPC_CALLRET_FATAL) {
                /* Call asynchronous handler with error code */
                callback(private, ENOENT, NULL);
                free(call);
                return;
        }

        call->callback = callback;
        call->private = private;

        if (callid == IPC_CALLRET_TEMPORARY) {
                /* Add asynchronous call to queue of non-dispatched async calls */
                call->u.msg.phoneid = phoneid;
                IPC_SET_METHOD(call->u.msg.data, method);
                IPC_SET_ARG1(call->u.msg.data, arg1);
                IPC_SET_ARG2(call->u.msg.data, arg2);

                list_append(&call->list, &queued_calls);
                return;
        }
        call->u.callid = callid;
        /* Add call to list of dispatched calls */
        list_append(&call->list, &dispatched_calls);
}


/** Send answer to a received call */
void ipc_answer(ipc_callid_t callid, ipcarg_t retval, ipcarg_t arg1,
                ipcarg_t arg2)
{
        __SYSCALL4(SYS_IPC_ANSWER_FAST, callid, retval, arg1, arg2);
}

/** Try to dispatch queed calls from async queue */
static void try_dispatch_queued_calls(void)
{
        async_call_t *call;
        ipc_callid_t callid;

        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);
                if (callid == IPC_CALLRET_FATAL) {
                        call->callback(call->private, ENOENT, NULL);
                        free(call);
                } else {
                        call->u.callid = callid;
                        list_append(&call->list, &dispatched_calls);
                }
        }
}

/** Handle received answer
 *
 * TODO: Make it use hash table
 *
 * @param callid Callid (with first bit set) of the answered call
 */
static void handle_answer(ipc_callid_t callid, ipc_call_t *data)
{
        link_t *item;
        async_call_t *call;

        callid &= ~IPC_CALLID_ANSWERED;
        
        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);
                        call->callback(call->private, 
                                       IPC_GET_RETVAL(*data),
                                       data);
                        return;
                }
        }
        printf("Received unidentified answer: %P!!!\n", callid);
}


/** Wait for IPC call and return
 *
 * - dispatch ASYNC reoutines in the background
 * @param data Space where the message is stored
 * @return Callid or 0 if nothing available and started with 
 *         IPC_WAIT_NONBLOCKING
 */
ipc_callid_t ipc_wait_for_call(ipc_call_t *call, int flags)
{
        ipc_callid_t callid;

        do {
                try_dispatch_queued_calls();

                callid = __SYSCALL2(SYS_IPC_WAIT, (sysarg_t)call, flags);
                /* Handle received answers */
                if (callid & IPC_CALLID_ANSWERED)
                        handle_answer(callid, call);
        } while (callid & IPC_CALLID_ANSWERED);

        return callid;
}

/** Ask destination to do a callback connection
 *
 * @return 0 - OK, error code
 */
int ipc_connect_to_me(int phoneid, int arg1, int arg2, ipcarg_t *phone)
{
        return ipc_call_sync_3(phoneid, IPC_M_CONNECT_TO_ME, arg1,
                               arg2, 0, 0, 0, phone);
}

/** Ask through phone for a new connection to some service
 *
 * @return new phoneid - OK, error code
 */
int ipc_connect_me_to(int phoneid, int arg1, int arg2)
{
        ipcarg_t newphid;
        int res;

        res =  ipc_call_sync_3(phoneid, IPC_M_CONNECT_ME_TO, arg1,
                               arg2, 0, 0, 0, &newphid);
        if (res)
                return res;
        return newphid;
}

/* Hang up specified phone */
int ipc_hangup(int phoneid)
{
        return __SYSCALL1(SYS_IPC_HANGUP, phoneid);
}

int ipc_register_irq(int irq)
{
        return __SYSCALL1(SYS_IPC_REGISTER_IRQ, irq);
}

int ipc_unregister_irq(int irq)
{
        return __SYSCALL1(SYS_IPC_UNREGISTER_IRQ, irq);
}