source: mainline/kernel/generic/src/ipc/ops/dataread.c@ 13dbaa8c

/*
 * 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 <mm/slab.h>
#include <abi/errno.h>
#include <syscall/copy.h>
#include <config.h>

static int request_preprocess(call_t *call, phone_t *phone)
{
        size_t size = IPC_GET_ARG2(call->data);

        if (size > DATA_XFER_LIMIT) {
                int flags = IPC_GET_ARG3(call->data);

                if (flags & IPC_XF_RESTRICT)
                        IPC_SET_ARG2(call->data, DATA_XFER_LIMIT);
                else
                        return ELIMIT;
        }

        return EOK;
}

static int answer_preprocess(call_t *answer, ipc_data_t *olddata)
{
        ASSERT(!answer->buffer);

        if (!IPC_GET_RETVAL(answer->data)) {
                /* The recipient agreed to send data. */
                uintptr_t src = IPC_GET_ARG1(answer->data);
                uintptr_t dst = IPC_GET_ARG1(*olddata);
                size_t max_size = IPC_GET_ARG2(*olddata);
                size_t size = IPC_GET_ARG2(answer->data);
                if (size && size <= max_size) {
                        /*
                         * Copy the destination VA so that this piece of
                         * information is not lost.
                         */
                        IPC_SET_ARG1(answer->data, dst);
                                
                        answer->buffer = malloc(size, 0);
                        int rc = copy_from_uspace(answer->buffer,
                            (void *) src, size);
                        if (rc) {
                                IPC_SET_RETVAL(answer->data, rc);
                                free(answer->buffer);
                                answer->buffer = NULL;
                        }
                } else if (!size) {
                        IPC_SET_RETVAL(answer->data, EOK);
                } else {
                        IPC_SET_RETVAL(answer->data, ELIMIT);
                }
        }

        return EOK;
}

static int answer_process(call_t *answer)
{
        if (answer->buffer) {
                uintptr_t dst = IPC_GET_ARG1(answer->data);
                size_t size = IPC_GET_ARG2(answer->data);
                int rc;

                rc = copy_to_uspace((void *) dst, answer->buffer, size);
                if (rc)
                        IPC_SET_RETVAL(answer->data, rc);
        }

        return EOK;
}

sysipc_ops_t ipc_m_data_read_ops = {
        .request_preprocess = request_preprocess,
        .request_process = null_request_process,
        .answer_preprocess = answer_preprocess,
        .answer_process = answer_process,
};

/** @}
 */