/*-
 *   BSD LICENSE
 *
 *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
 *   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.
 *     * 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
 *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 *   OWNER OR CONTRIBUTORS 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.
 */

#include <unistd.h>
#include <limits.h>
#include <string.h>
#include <dirent.h>

#include <rte_log.h>
#include <rte_eal.h>
#include <rte_lcore.h>
#include <rte_common.h>
#include <rte_string_fns.h>
#include <rte_debug.h>

#include "eal_private.h"
#include "eal_filesystem.h"
#include "eal_thread.h"

#define SYS_CPU_DIR "/sys/devices/system/cpu/cpu%u"
#define CORE_ID_FILE "topology/core_id"
#define NUMA_NODE_PATH "/sys/devices/system/node"

/* Check if a cpu is present by the presence of the cpu information for it */
int
eal_cpu_detected(unsigned lcore_id)
{
	char path[PATH_MAX];
	int len = snprintf(path, sizeof(path), SYS_CPU_DIR
		"/"CORE_ID_FILE, lcore_id);
	if (len <= 0 || (unsigned)len >= sizeof(path))
		return 0;
	if (access(path, F_OK) != 0)
		return 0;

	return 1;
}

/*
 * Get CPU socket id (NUMA node) for a logical core.
 *
 * This searches each nodeX directories in /sys for the symlink for the given
 * lcore_id and returns the numa node where the lcore is found. If lcore is not
 * found on any numa node, returns zero.
 */
unsigned
eal_cpu_socket_id(unsigned lcore_id)
{
	unsigned socket;

	for (socket = 0; socket < RTE_MAX_NUMA_NODES; socket++) {
		char path[PATH_MAX];

		snprintf(path, sizeof(path), "%s/node%u/cpu%u", NUMA_NODE_PATH,
				socket, lcore_id);
		if (access(path, F_OK) == 0)
			return socket;
	}
	return 0;
}

/* Get the cpu core id value from the /sys/.../cpuX core_id value */
unsigned
eal_cpu_core_id(unsigned lcore_id)
{
	char path[PATH_MAX];
	unsigned long id;

	int len = snprintf(path, sizeof(path), SYS_CPU_DIR "/%s", lcore_id, CORE_ID_FILE);
	if (len <= 0 || (unsigned)len >= sizeof(path))
		goto err;
	if (eal_parse_sysfs_value(path, &id) != 0)
		goto err;
	return (unsigned)id;

err:
	RTE_LOG(ERR, EAL, "Error reading core id value from %s "
			"for lcore %u - assuming core 0\n", SYS_CPU_DIR, lcore_id);
	return 0;
}