examples/multi_process/l2fwd_fork/flib.c

/*-
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 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   All rights reserved.
 *
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 *   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.
 *     * Neither the name of Intel Corporation nor the names of its
 *       contributors may be used to endorse or promote products derived
 *       from this software without specific prior written permission.
 *
 *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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 *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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 *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <inttypes.h>
#include <sys/types.h>
#include <sys/queue.h>
#include <sys/wait.h>
#include <sys/prctl.h>
#include <netinet/in.h>
#include <setjmp.h>
#include <stdarg.h>
#include <ctype.h>
#include <errno.h>
#include <getopt.h>
#include <dirent.h>
#include <signal.h>

#include <rte_common.h>
#include <rte_log.h>
#include <rte_malloc.h>
#include <rte_memory.h>
#include <rte_memcpy.h>
#include <rte_eal.h>
#include <rte_launch.h>
#include <rte_atomic.h>
#include <rte_cycles.h>
#include <rte_prefetch.h>
#include <rte_lcore.h>
#include <rte_per_lcore.h>
#include <rte_branch_prediction.h>
#include <rte_interrupts.h>
#include <rte_random.h>
#include <rte_debug.h>
#include <rte_ether.h>
#include <rte_ethdev.h>
#include <rte_mempool.h>
#include <rte_mbuf.h>
#include <rte_string_fns.h>

#include "flib.h"

#define SIG_PARENT_EXIT SIGUSR1

struct lcore_stat {
    pid_t pid;           
    lcore_function_t *f; 
    void *arg;           
    slave_exit_notify *cb_fn;
} __rte_cache_aligned;


static struct lcore_stat *core_cfg;
static uint16_t *lcore_cfg = NULL;

/* signal handler to be notified after parent leaves */
static void
sighand_parent_exit(int sig)
{
    printf("lcore = %u : Find parent leaves, sig=%d\n", rte_lcore_id(),
            sig);
    printf("Child leaving\n");
    exit(0);

    return;
}

static int
slave_proc_func(void)
{
    struct rte_config *config;
    unsigned slave_id = rte_lcore_id();
    struct lcore_stat *cfg = &core_cfg[slave_id];

    if (prctl(PR_SET_PDEATHSIG, SIG_PARENT_EXIT, 0, 0, 0, 0) != 0)
        printf("Warning: Slave can't register for being notified in"
               "case master process exited\n");
    else {
        struct sigaction act;
        memset(&act, 0 , sizeof(act));
        act.sa_handler = sighand_parent_exit;
        if (sigaction(SIG_PARENT_EXIT, &act, NULL) != 0)
            printf("Fail to register signal handler:%d\n", SIG_PARENT_EXIT);
    }

    /* Set slave process to SECONDARY to avoid operation like dev_start/stop etc */
    config = rte_eal_get_configuration();
    if (NULL == config)
        printf("Warning:Can't get rte_config\n");
    else
        config->process_type = RTE_PROC_SECONDARY;

    printf("Core %u is ready (pid=%d)\n", slave_id, (int)cfg->pid);

    exit(cfg->f(cfg->arg));
}

static int
lcore_func(void *arg __attribute__((unused)))
{
    unsigned slave_id = rte_lcore_id();
    struct lcore_stat *cfg = &core_cfg[slave_id];
    int pid, stat;

    if (rte_get_master_lcore() == slave_id)
        return cfg->f(cfg->arg);

    /* fork a slave process */
    pid = fork();

    if (pid == -1) {
        printf("Failed to fork\n");
        return -1;
    } else if (pid == 0) /* child */
        return slave_proc_func();
    else { /* parent */
        cfg->pid = pid;

        waitpid(pid, &stat, 0);

        cfg->pid = 0;
        cfg->f = NULL;
        cfg->arg = NULL;
        /* Notify slave's exit if applicable */
        if(cfg->cb_fn)
            cfg->cb_fn(slave_id, stat);
        return stat;
    }
}

static int
lcore_id_init(void)
{
    int i;
    /* Setup lcore ID allocation map */
    lcore_cfg = rte_zmalloc("LCORE_ID_MAP",
                        sizeof(uint16_t) * RTE_MAX_LCORE,
                        RTE_CACHE_LINE_SIZE);

    if(lcore_cfg == NULL)
        rte_panic("Failed to malloc\n");

    for (i = 0; i < RTE_MAX_LCORE; i++) {
        if (rte_lcore_is_enabled(i))
            lcore_cfg[i] = 1;
    }
    return 0;
}

int
flib_assign_lcore_id(void)
{
    unsigned i;
    int ret;

    if (rte_lcore_id() != 0)
        return -1;

    do {
        /* Find a lcore id not used yet, avoid to use lcore ID 0 */
        for (i = 1; i < RTE_MAX_LCORE; i++) {
            if (lcore_cfg[i] == 0)
                break;
        }
        if (i == RTE_MAX_LCORE)
            return -1;

        /* Assign new lcore id to this thread */

        ret = rte_atomic16_cmpset(&lcore_cfg[i], 0, 1);
    } while (unlikely(ret == 0));

    RTE_PER_LCORE(_lcore_id) = i;
    return i;
}

void
flib_free_lcore_id(unsigned lcore_id)
{
    /* id is not valid or belongs to pinned core id */
    if (lcore_id >= RTE_MAX_LCORE || lcore_id == 0 ||
        rte_lcore_is_enabled(lcore_id))
        return;

    lcore_cfg[lcore_id] = 0;
}

int
flib_register_slave_exit_notify(unsigned slave_id,
    slave_exit_notify *cb)
{
    if (cb == NULL)
        return -EFAULT;

    if (!rte_lcore_is_enabled(slave_id))
        return -ENOENT;

    core_cfg[slave_id].cb_fn = cb;

    return 0;
}

enum slave_stat
flib_query_slave_status(unsigned slave_id)
{
    if (!rte_lcore_is_enabled(slave_id))
        return ST_FREEZE;
    /* pid only be set when slave process spawned */
    if (core_cfg[slave_id].pid != 0)
        return ST_RUN;
    else
        return ST_IDLE;
}

int
flib_remote_launch(lcore_function_t *f,
                    void *arg, unsigned slave_id)
{
    if (f == NULL)
        return -1;

    if (!rte_lcore_is_enabled(slave_id))
        return -1;

    /* Wait until specific lcore state change to WAIT */
    rte_eal_wait_lcore(slave_id);

    core_cfg[slave_id].f = f;
    core_cfg[slave_id].arg = arg;

    return rte_eal_remote_launch(lcore_func, NULL, slave_id);
}

int
flib_mp_remote_launch(lcore_function_t *f, void *arg,
            enum rte_rmt_call_master_t call_master)
{
    int i;

    RTE_LCORE_FOREACH_SLAVE(i) {
        core_cfg[i].arg = arg;
        core_cfg[i].f = f;
    }

    return rte_eal_mp_remote_launch(lcore_func, NULL, call_master);
}

int
flib_init(void)
{
    if ((core_cfg = rte_zmalloc("core_cfg",
        sizeof(struct lcore_stat) * RTE_MAX_LCORE,
        RTE_CACHE_LINE_SIZE)) == NULL ) {
        printf("rte_zmalloc failed\n");
        return -1;
    }

    if (lcore_id_init() != 0) {
        printf("lcore_id_init failed\n");
        return -1;
    }

    return 0;
}