examples/multi_process/l2fwd_fork/flib.c

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2010-2014 Intel Corporation
 */
#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;
}