source: mainline/kernel/generic/src/ipc/ops/conctmeto.c@ 813fc8c

/*
 * Copyright (c) 2006 Ondrej Palkovsky
 * Copyright (c) 2012 Jakub Jermar
 * 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 <ipc/sysipc_ops.h>
#include <ipc/ipc.h>
#include <ipc/ipcrsc.h>
#include <abi/errno.h>
#include <arch.h>

static errno_t request_preprocess(call_t *call, phone_t *phone)
{
        cap_handle_t phone_handle;
        errno_t rc = phone_alloc(TASK, &phone_handle);
        if (rc != EOK) {
                call->priv = -1;
                return rc;
        }

        /*
         * The capability is now published, but the phone is not connected yet.
         * The user cannot use it to send anything over it, in fact the
         * userspace can only unpublish and free the capability at this point.
         *
         * We now proceed to test the capability is still there. We don't care
         * if the user destroyed the old one and recreated a new published one
         * of the same type under the same handle.
         *
         * If the capability is in place we temporarily unpublish it to make
         * sure the user cannot fiddle with it while we are connecting.
         */

        kobject_t *phone_obj = cap_unpublish(TASK, phone_handle,
            KOBJECT_TYPE_PHONE);
        if (!phone_obj) {
                /*
                 * Another thread of the same task can destroy the new
                 * capability before we manage to get a reference from it.
                 */
                call->priv = -1;
                return ENOENT;
        }

        /* Hand over phone_obj's reference to ARG5 */
        IPC_SET_ARG5(call->data, (sysarg_t) phone_obj->phone);

        /* Remember the handle */
        call->priv = phone_handle;

        return EOK;
}

static errno_t request_forget(call_t *call)
{
        cap_handle_t phone_handle = (cap_handle_t) call->priv;

        if (phone_handle < 0)
                return EOK;

        /* Hand over reference from ARG5 to phone->kobject */
        phone_t *phone = (phone_t *) IPC_GET_ARG5(call->data);
        /* Drop phone->kobject's reference */
        kobject_put(phone->kobject);
        cap_free(TASK, phone_handle);

        return EOK;
}

static errno_t answer_preprocess(call_t *answer, ipc_data_t *olddata)
{
        /* Hand over reference from ARG5 to phone */
        phone_t *phone = (phone_t *) IPC_GET_ARG5(*olddata);

        /*
         * Get an extra reference and pass it in the answer data.
         */
        kobject_add_ref(phone->kobject);
        IPC_SET_ARG5(answer->data, (sysarg_t) phone);

        /* If the user accepted the call, connect */
        if (IPC_GET_RETVAL(answer->data) == EOK) {
                /* Hand over reference from phone to the answerbox */
                (void) ipc_phone_connect(phone, &TASK->answerbox);
        } else {
                kobject_put(phone->kobject);
        }

        return EOK;
}

static errno_t answer_process(call_t *answer)
{
        cap_handle_t phone_handle = (cap_handle_t) answer->priv;
        phone_t *phone = (phone_t *) IPC_GET_ARG5(answer->data);

        if (IPC_GET_RETVAL(answer->data)) {
                if (phone_handle >= 0) {
                        /*
                         * Cleanup the unpublished capability and drop
                         * phone->kobject's reference.
                         */
                        kobject_put(phone->kobject);
                        cap_free(TASK, phone_handle);
                }
        } else {
                /*
                 * Publish the capability. Publishing the capability this late
                 * is important for ipc_cleanup() where we want to have a
                 * capability for each phone that wasn't hung up by the user.
                 */
                cap_publish(TASK, phone_handle, phone->kobject);

                IPC_SET_ARG5(answer->data, phone_handle);
        }

        return EOK;
}

sysipc_ops_t ipc_m_connect_me_to_ops = {
        .request_preprocess = request_preprocess,
        .request_forget = request_forget,
        .request_process = null_request_process,
        .answer_cleanup = null_answer_cleanup,
        .answer_preprocess = answer_preprocess,
        .answer_process = answer_process,
};

/** @}
 */