source: mainline/generic/src/ipc/sysipc.c@ ad64a2d

/*
 * 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 <arch.h>
#include <proc/task.h>

#include <errno.h>
#include <mm/page.h>
#include <memstr.h>
#include <debug.h>
#include <ipc/ipc.h>
#include <ipc/sysipc.h>
#include <ipc/ipcrsc.h>


#include <print.h>
#include <arch.h>
#include <proc/thread.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)
                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;
        return 0;
}

/** Interpret process answer as control information */
static inline void answer_preprocess(call_t *answer, ipc_data_t *olddata)
{
        int phoneid;

        if (IPC_GET_RETVAL(answer->data) == EHANGUP) {
                /* Atomic operation */
                answer->data.phone->callee = NULL;
        }

        if (!olddata)
                return;

        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);
                }
        }
}

/** Called before the request is sent
 *
 * @return 0 - no error, -1 - report error to user
 */
static int request_preprocess(call_t *call)
{
        int newphid;

        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;
        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;

        ipc_call_static_init(&call);
        copy_from_uspace(&call.data.args, &question->args, sizeof(call.data.args));

        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);

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

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

        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;

        if (check_call_limit())
                return IPC_CALLRET_TEMPORARY;

        GET_CHECK_PHONE(phone, phoneid, return IPC_CALLRET_FATAL);

        call = ipc_call_alloc();
        copy_from_uspace(&call->data.args, &data->args, sizeof(call->data.args));
        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;

        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);
        answer_preprocess(call, saveddata ? &saved_data : NULL);

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

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

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

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

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

        return 0;
}

/** 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 taskid On 'CONNECT_ME_TO' call it is filled with 'taskid' of
 *               the caller.
 * @param flags
 * @return Callid, if callid & 1, then the call is answer
 */
__native sys_ipc_wait_for_call(ipc_data_t *calldata, __native flags)
{
        call_t *call;

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

        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 */
        STRUCT_TO_USPACE(calldata, &call->data);
        return (__native)call;
}