HelenOS sources

root/kernel/generic/src/ipc/ops/dataread.c

DEFINITIONS

1. request_preprocess
2. answer_preprocess
3. answer_process

/*
 * 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 kernel_generic_ipc
 * @{
 */
/** @file
 */

#include <assert.h>
#include <ipc/sysipc_ops.h>
#include <ipc/ipc.h>
#include <stdlib.h>
#include <abi/errno.h>
#include <syscall/copy.h>
#include <config.h>

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

        if (!ipc_get_retval(&answer->data)) {
                /* The recipient agreed to send data. */
                uspace_addr_t src = ipc_get_arg1(&answer->data);
                uspace_addr_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);
                        if (!answer->buffer) {
                                ipc_set_retval(&answer->data, ENOMEM);
                                return EOK;
                        }
                        errno_t rc = copy_from_uspace(answer->buffer,
                            src, size);
                        if (rc) {
                                ipc_set_retval(&answer->data, rc);
                                /*
                                 * answer->buffer will be cleaned up in
                                 * ipc_call_free().
                                 */
                                return EOK;
                        }
                } else if (!size) {
                        ipc_set_retval(&answer->data, EOK);
                } else {
                        ipc_set_retval(&answer->data, ELIMIT);
                }
        }

        return EOK;
}

static errno_t answer_process(call_t *answer)
{
        if (answer->buffer) {
                uspace_addr_t dst = ipc_get_arg1(&answer->data);
                size_t size = ipc_get_arg2(&answer->data);
                errno_t rc;

                rc = copy_to_uspace(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_forget = null_request_forget,
        .request_process = null_request_process,
        .answer_cleanup = null_answer_cleanup,
        .answer_preprocess = answer_preprocess,
        .answer_process = answer_process,
};

/** @}
 */