source: mainline/uspace/lib/device/src/io/chardev_srv.c

/*
 * Copyright (c) 2023 Jiri Svoboda
 * 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 libdevice
 * @{
 */
/**
 * @file
 * @brief Character device server stub
 */
#include <errno.h>
#include <io/chardev_srv.h>
#include <ipc/chardev.h>
#include <macros.h>
#include <stdlib.h>
#include <stddef.h>

static chardev_srv_t *chardev_srv_create(chardev_srvs_t *);

static void chardev_read_srv(chardev_srv_t *srv, ipc_call_t *icall)
{
        void *buf;
        size_t size;
        size_t nread;
        chardev_flags_t flags;
        errno_t rc;

        flags = ipc_get_arg1(icall);

        ipc_call_t call;
        if (!async_data_read_receive(&call, &size)) {
                async_answer_0(&call, EINVAL);
                async_answer_0(icall, EINVAL);
                return;
        }

        buf = malloc(size);
        if (buf == NULL) {
                async_answer_0(&call, ENOMEM);
                async_answer_0(icall, ENOMEM);
                return;
        }

        if (srv->srvs->ops->read == NULL) {
                async_answer_0(&call, ENOTSUP);
                async_answer_0(icall, ENOTSUP);
                free(buf);
                return;
        }

        rc = srv->srvs->ops->read(srv, buf, size, &nread, flags);
        if (rc != EOK && nread == 0) {
                async_answer_0(&call, rc);
                async_answer_0(icall, rc);
                free(buf);
                return;
        }

        async_data_read_finalize(&call, buf, nread);

        free(buf);
        async_answer_2(icall, EOK, (sysarg_t) rc, nread);
}

static void chardev_write_srv(chardev_srv_t *srv, ipc_call_t *icall)
{
        void *data;
        size_t size;
        size_t nwr;
        errno_t rc;

        rc = async_data_write_accept(&data, false, 0, 0, 0, &size);
        if (rc != EOK) {
                async_answer_0(icall, rc);
                return;
        }

        if (srv->srvs->ops->write == NULL) {
                async_answer_0(icall, ENOTSUP);
                return;
        }

        rc = srv->srvs->ops->write(srv, data, size, &nwr);
        free(data);
        if (rc != EOK && nwr == 0) {
                async_answer_0(icall, rc);
                return;
        }

        async_answer_2(icall, EOK, (sysarg_t) rc, nwr);
}

static chardev_srv_t *chardev_srv_create(chardev_srvs_t *srvs)
{
        chardev_srv_t *srv;

        srv = calloc(1, sizeof(chardev_srv_t));
        if (srv == NULL)
                return NULL;

        srv->srvs = srvs;
        return srv;
}

void chardev_srvs_init(chardev_srvs_t *srvs)
{
        srvs->ops = NULL;
        srvs->sarg = NULL;
}

errno_t chardev_conn(ipc_call_t *icall, chardev_srvs_t *srvs)
{
        chardev_srv_t *srv;
        errno_t rc;

        /* Accept the connection */
        async_accept_0(icall);

        srv = chardev_srv_create(srvs);
        if (srv == NULL)
                return ENOMEM;

        if (srvs->ops->open != NULL) {
                rc = srvs->ops->open(srvs, srv);
                if (rc != EOK)
                        return rc;
        }

        while (true) {
                ipc_call_t call;
                async_get_call(&call);
                sysarg_t method = ipc_get_imethod(&call);

                if (!method) {
                        /* The other side has hung up */
                        async_answer_0(&call, EOK);
                        break;
                }

                switch (method) {
                case CHARDEV_READ:
                        chardev_read_srv(srv, &call);
                        break;
                case CHARDEV_WRITE:
                        chardev_write_srv(srv, &call);
                        break;
                default:
                        if (srv->srvs->ops->def_handler != NULL)
                                srv->srvs->ops->def_handler(srv, &call);
                        else
                                async_answer_0(&call, ENOTSUP);
                }
        }

        if (srvs->ops->close != NULL)
                rc = srvs->ops->close(srv);
        else
                rc = EOK;

        free(srv);

        return rc;
}

/** @}
 */