bufp-label.c

/*
 * Copyright (C) 2009 Philippe Gerum <rpm@xenomai.org>.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.

 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA.
 *
 *
 * BUFP-based client/server demo, using the read(2)/write(2)
 * system calls to exchange data over a socket.
 *
 * In this example, two sockets are created.  A server thread (reader)
 * is bound to a real-time port and receives a stream of bytes sent to
 * this port from a client thread (writer).
 */
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <signal.h>
#include <string.h>
#include <pthread.h>
#include <errno.h>
#include <rtdm/ipc.h>

pthread_t svtid, cltid;

#define BUFP_PORT_LABEL  "bufp-demo"

static const char *msg[] = {
        "Surfing With The Alien",
        "Lords of Karma",
        "Banana Mango",
        "Psycho Monkey",
        "Luminous Flesh Giants",
        "Moroccan Sunset",
        "Satch Boogie",
        "Flying In A Blue Dream",
        "Ride",
        "Summer Song",
        "Speed Of Light",
        "Crystal Planet",
        "Raspberry Jam Delta-V",
        "Champagne?",
        "Clouds Race Across The Sky",
        "Engines Of Creation"
};

static void fail(const char *reason)
{
        perror(reason);
        exit(EXIT_FAILURE);
}

static void *server(void *arg)
{
        struct rtipc_port_label plabel;
        struct sockaddr_ipc saddr;
        char buf[128];
        size_t bufsz;
        int ret, s;

        s = socket(AF_RTIPC, SOCK_DGRAM, IPCPROTO_BUFP);
        if (s < 0)
                fail("socket");

        /*
         * Set a 16k buffer for the server endpoint. This
         * configuration must be done prior to binding the socket to a
         * port.
         */
        bufsz = 16384; /* bytes */
        ret = setsockopt(s, SOL_BUFP, BUFP_BUFSZ,
                         &bufsz, sizeof(bufsz));
        if (ret)
                fail("setsockopt");

        /*
         * Set a port label. This name will be registered when
         * binding, in addition to the port number (if given).
         */
        strcpy(plabel.label, BUFP_PORT_LABEL);
        ret = setsockopt(s, SOL_BUFP, BUFP_LABEL,
                         &plabel, sizeof(plabel));
        if (ret)
                fail("setsockopt");

        /*
         * Bind the socket to the port. Assign that port a label, so
         * that peers may use a descriptive information to locate
         * it. Labeled ports will appear in the
         * /proc/xenomai/registry/rtipc/bufp directory once the socket
         * is bound.
         *
         * saddr.sipc_port specifies the port number to use. If -1 is
         * passed, the BUFP driver will auto-select an idle port.
         */
        saddr.sipc_family = AF_RTIPC;
        saddr.sipc_port = -1;
        ret = bind(s, (struct sockaddr *)&saddr, sizeof(saddr));
        if (ret)
                fail("bind");

        for (;;) {
                ret = read(s, buf, sizeof(buf));
                if (ret < 0) {
                        close(s);
                        fail("read");
                }
                printf("%s: received %d bytes, \"%.*s\"\n",
                       __FUNCTION__, ret, ret, buf);
        }

        return NULL;
}

static void *client(void *arg)
{
        struct rtipc_port_label plabel;
        struct sockaddr_ipc svsaddr;
        int ret, s, n = 0, len;
        struct timespec ts;

        s = socket(AF_RTIPC, SOCK_DGRAM, IPCPROTO_BUFP);
        if (s < 0)
                fail("socket");

        /*
         * Set the port label. This name will be used to find the peer
         * when connecting, instead of the port number. The label must
         * be set _after_ the socket is bound to the port, so that
         * BUFP does not try to register this label for the client
         * port as well (like the server thread did).
         */
        strcpy(plabel.label, BUFP_PORT_LABEL);
        ret = setsockopt(s, SOL_BUFP, BUFP_LABEL,
                         &plabel, sizeof(plabel));
        if (ret)
                fail("setsockopt");

        memset(&svsaddr, 0, sizeof(svsaddr));
        svsaddr.sipc_family = AF_RTIPC;
        svsaddr.sipc_port = -1; /* Tell BUFP to search by label. */
        ret = connect(s, (struct sockaddr *)&svsaddr, sizeof(svsaddr));
        if (ret)
                fail("connect");

        for (;;) {
                len = strlen(msg[n]);
                ret = write(s, msg[n], len);
                if (ret < 0) {
                        close(s);
                        fail("write");
                }
                printf("%s: sent %d bytes, \"%.*s\"\n",
                       __FUNCTION__, ret, ret, msg[n]);
                n = (n + 1) % (sizeof(msg) / sizeof(msg[0]));
                /*
                 * We run in full real-time mode (i.e. primary mode),
                 * so we have to let the system breathe between two
                 * iterations.
                 */
                ts.tv_sec = 0;
                ts.tv_nsec = 500000000; /* 500 ms */
                clock_nanosleep(CLOCK_REALTIME, 0, &ts, NULL);
        }

        return NULL;
}

int main(int argc, char **argv)
{
        struct sched_param svparam = {.sched_priority = 71 };
        struct sched_param clparam = {.sched_priority = 70 };
        pthread_attr_t svattr, clattr;
        sigset_t set;
        int sig;

        sigemptyset(&set);
        sigaddset(&set, SIGINT);
        sigaddset(&set, SIGTERM);
        sigaddset(&set, SIGHUP);
        pthread_sigmask(SIG_BLOCK, &set, NULL);

        pthread_attr_init(&svattr);
        pthread_attr_setdetachstate(&svattr, PTHREAD_CREATE_JOINABLE);
        pthread_attr_setinheritsched(&svattr, PTHREAD_EXPLICIT_SCHED);
        pthread_attr_setschedpolicy(&svattr, SCHED_FIFO);
        pthread_attr_setschedparam(&svattr, &svparam);

        errno = pthread_create(&svtid, &svattr, &server, NULL);
        if (errno)
                fail("pthread_create");

        pthread_attr_init(&clattr);
        pthread_attr_setdetachstate(&clattr, PTHREAD_CREATE_JOINABLE);
        pthread_attr_setinheritsched(&clattr, PTHREAD_EXPLICIT_SCHED);
        pthread_attr_setschedpolicy(&clattr, SCHED_FIFO);
        pthread_attr_setschedparam(&clattr, &clparam);

        errno = pthread_create(&cltid, &clattr, &client, NULL);
        if (errno)
                fail("pthread_create");

        sigwait(&set, &sig);
        pthread_cancel(svtid);
        pthread_cancel(cltid);
        pthread_join(svtid, NULL);
        pthread_join(cltid, NULL);

        return 0;
}