xref: /dpdk/examples/l2fwd-keepalive/shm.c (revision 13830b98b2bcf6a8a1aa8edde5132907c053861c)

/* SPDX-License-Identifier: BSD-3-Clause
 * Copyright(c) 2016 Intel Corporation
 */

#include <time.h>

#include <rte_common.h>
#include <rte_keepalive.h>

#include "shm.h"

struct rte_keepalive_shm *rte_keepalive_shm_create(void)
{
	int fd;
	int idx_core;
	struct rte_keepalive_shm *ka_shm;

	/* If any existing object is not unlinked, it makes it all too easy
	 * for clients to end up with stale shared memory blocks when
	 * restarted. Unlinking makes sure subsequent shm_open by clients
	 * will get the new block mapped below.
	 */
	if (shm_unlink(RTE_KEEPALIVE_SHM_NAME) == -1 && errno != ENOENT)
		RTE_LOG(NOTICE, L2FWD,
			"Warning: Error unlinking stale %s (%s)\n",
			RTE_KEEPALIVE_SHM_NAME, strerror(errno));

	fd = shm_open(RTE_KEEPALIVE_SHM_NAME,
		O_CREAT | O_TRUNC | O_RDWR, 0666);
	if (fd < 0)
		RTE_LOG(ERR, L2FWD, "Failed to open %s as SHM (%s)\n",
			RTE_KEEPALIVE_SHM_NAME, strerror(errno));
	else if (ftruncate(fd, sizeof(struct rte_keepalive_shm)) != 0)
		RTE_LOG(ERR, L2FWD, "Failed to resize SHM (%s)\n", strerror(errno));
	else {
		ka_shm = (struct rte_keepalive_shm *) mmap(
			0, sizeof(struct rte_keepalive_shm),
			PROT_READ | PROT_WRITE,	MAP_SHARED, fd, 0);
		close(fd);
		if (ka_shm == MAP_FAILED)
			RTE_LOG(ERR, L2FWD, "Failed to mmap SHM (%s)\n", strerror(errno));
		else {
			memset(ka_shm, 0, sizeof(struct rte_keepalive_shm));

			/* Initialize the semaphores for IPC/SHM use */
			if (sem_init(&ka_shm->core_died, 1, 0) != 0) {
				RTE_LOG(ERR, L2FWD, "Failed to setup SHM semaphore (%s)\n",
					strerror(errno));
				munmap(ka_shm,
					sizeof(struct rte_keepalive_shm));
				return NULL;
			}

			/* Set all cores to 'not present' */
			for (idx_core = 0;
					idx_core < RTE_KEEPALIVE_MAXCORES;
					idx_core++) {
				ka_shm->core_state[idx_core] =
					RTE_KA_STATE_UNUSED;
				ka_shm->core_last_seen_times[idx_core] = 0;
			}

			return ka_shm;
		}
	}
return NULL;
}

void rte_keepalive_relayed_state(struct rte_keepalive_shm *shm,
	const int id_core, const enum rte_keepalive_state core_state,
	__rte_unused uint64_t last_alive)
{
	int count;

	shm->core_state[id_core] = core_state;
	shm->core_last_seen_times[id_core] = last_alive;

	if (core_state == RTE_KEEPALIVE_SHM_DEAD) {
		/* Since core has died, also signal ka_agent.
		 *
		 * Limit number of times semaphore can be incremented, in case
		 * ka_agent is not active.
		 */
		if (sem_getvalue(&shm->core_died, &count) == -1) {
			RTE_LOG(ERR, L2FWD, "Semaphore check failed(%s)\n",
				strerror(errno));
			return;
		}
		if (count > 1)
			return;

		if (sem_post(&shm->core_died) != 0)
			RTE_LOG(ERR, L2FWD, "Failed to increment semaphore (%s)\n",
				strerror(errno));
	}
}

void rte_keepalive_shm_cleanup(struct rte_keepalive_shm *ka_shm)
{
	if (shm_unlink(RTE_KEEPALIVE_SHM_NAME) == -1 && errno != ENOENT)
		RTE_LOG(NOTICE, L2FWD, "Warning: Error unlinking  %s (%s)\n",
			RTE_KEEPALIVE_SHM_NAME, strerror(errno));

	if (ka_shm && munmap(ka_shm, sizeof(struct rte_keepalive_shm)) != 0)
		RTE_LOG(ERR, L2FWD, "Warning: munmap() failed: %s\n",
			strerror(errno));
}