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/*-
 *   BSD LICENSE
 * 
 *   Copyright(c) 2010-2012 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.
 * 
 *  version: DPDK.L.1.2.3-3
 */

#include <string.h>
#include <sys/types.h>
#include <dirent.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <inttypes.h>
#include <stdarg.h>
#include <errno.h>
#include <sys/queue.h>

#include "rte_memory.h"
#include "rte_memzone.h"
#include "rte_tailq.h"
#include "rte_eal.h"
#include "rte_launch.h"
#include "rte_per_lcore.h"
#include "rte_lcore.h"
#include "rte_debug.h"
#include "rte_log.h"
#include "rte_common.h"
#include "rte_string_fns.h"
#include "eal_internal_cfg.h"
#include "eal_hugepages.h"

static const char sys_dir_path[] = "/sys/kernel/mm/hugepages";

static int32_t
get_num_hugepages(const char *subdir)
{
	const char nr_hp_file[] = "nr_hugepages";
	char path[BUFSIZ];
	unsigned num_pages = 0;

	rte_snprintf(path, sizeof(path), "%s/%s/%s",
			sys_dir_path, subdir, nr_hp_file);
	FILE *fd = fopen(path, "r");
	if (fd == NULL || fscanf(fd, "%u", &num_pages) != 1)
		rte_panic("Error reading file '%s'\n", path);
	fclose(fd);

	return num_pages;
}

static uint64_t
get_default_hp_size(void)
{
	const char proc_meminfo[] = "/proc/meminfo";
	const char str_hugepagesz[] = "Hugepagesize:";
	unsigned hugepagesz_len = sizeof(str_hugepagesz) - 1;
	char buffer[256];
	unsigned long long size = 0;

	FILE *fd = fopen(proc_meminfo, "r");
	if (fd == NULL)
		rte_panic("Cannot open %s\n", proc_meminfo);
	while(fgets(buffer, sizeof(buffer), fd)){
		if (strncmp(buffer, str_hugepagesz, hugepagesz_len) == 0){
			size = rte_str_to_size(&buffer[hugepagesz_len]);
			break;
		}
	}
	fclose(fd);
	if (size == 0)
		rte_panic("Cannot get default hugepage size from %s\n", proc_meminfo);
	return size;
}

static const char *
get_hugepage_dir(uint64_t hugepage_sz)
{
	enum proc_mount_fieldnames {
		DEVICE = 0,
		MOUNTPT,
		FSTYPE,
		OPTIONS,
		_FIELDNAME_MAX
	};
	static uint64_t default_size = 0;
	const char proc_mounts[] = "/proc/mounts";
	const char hugetlbfs_str[] = "hugetlbfs";
	const size_t htlbfs_str_len = sizeof(hugetlbfs_str) - 1;
	const char pagesize_opt[] = "pagesize=";
	const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
	const char split_tok = ' ';
	char *splitstr[_FIELDNAME_MAX];
	char buf[BUFSIZ];
	char *retval = NULL;

	FILE *fd = fopen(proc_mounts, "r");
	if (fd == NULL)
		rte_panic("Cannot open %s\n", proc_mounts);

	if (default_size == 0)
		default_size = get_default_hp_size();

	while (fgets(buf, sizeof(buf), fd)){
		if (rte_strsplit(buf, sizeof(buf), splitstr, _FIELDNAME_MAX,
				split_tok) != _FIELDNAME_MAX) {
			RTE_LOG(ERR, EAL, "Error parsing %s\n", proc_mounts);
			break; /* return NULL */
		}

		/* we have a specified --huge-dir option, only examine that dir */
		if (internal_config.hugepage_dir != NULL &&
				strcmp(splitstr[MOUNTPT], internal_config.hugepage_dir) != 0)
			continue;

		if (strncmp(splitstr[FSTYPE], hugetlbfs_str, htlbfs_str_len) == 0){
			const char *pagesz_str = strstr(splitstr[OPTIONS], pagesize_opt);

			/* if no explicit page size, the default page size is compared */
			if (pagesz_str == NULL){
				if (hugepage_sz == default_size){
					retval = strdup(splitstr[MOUNTPT]);
					break;
				}
			}
			/* there is an explicit page size, so check it */
			else {
				uint64_t pagesz = rte_str_to_size(&pagesz_str[pagesize_opt_len]);
				if (pagesz == hugepage_sz) {
					retval = strdup(splitstr[MOUNTPT]);
					break;
				}
			}
		} /* end if strncmp hugetlbfs */
	} /* end while fgets */

	fclose(fd);
	return retval;
}

static inline void
swap_hpi(struct hugepage_info *a, struct hugepage_info *b)
{
	char buf[sizeof(*a)];
	memcpy(buf, a, sizeof(*a));
	memcpy(a, b, sizeof(*a));
	memcpy(b, buf, sizeof(*a));
}

int
eal_hugepage_info_init(void)
{
	const char dirent_start_text[] = "hugepages-";
	const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
	unsigned i, num_sizes = 0;

	DIR *dir = opendir(sys_dir_path);
	if (dir == NULL)
		rte_panic("Cannot open directory %s to read system hugepage info\n",
				sys_dir_path);

	struct dirent *dirent = readdir(dir);
	while(dirent != NULL){
		if (strncmp(dirent->d_name, dirent_start_text, dirent_start_len) == 0){
			struct hugepage_info *hpi = \
					&internal_config.hugepage_info[num_sizes];
			hpi->hugepage_sz = rte_str_to_size(&dirent->d_name[dirent_start_len]);
			hpi->num_pages = get_num_hugepages(dirent->d_name);
			hpi->hugedir = get_hugepage_dir(hpi->hugepage_sz);
			if (hpi->hugedir == NULL){
				RTE_LOG(INFO, EAL, "%u hugepages of size %llu reserved, "\
						"but no mounted hugetlbfs found for that size\n",
						hpi->num_pages,
						(unsigned long long)hpi->hugepage_sz);
				hpi->num_pages = 0;
			} else
				num_sizes++;
		}
		dirent = readdir(dir);
	}
	closedir(dir);
	internal_config.num_hugepage_sizes = num_sizes;

	/* sort the page directory entries by size, largest to smallest */
	for (i = 0; i < num_sizes; i++){
		unsigned j;
		for (j = i+1; j < num_sizes; j++)
			if (internal_config.hugepage_info[j-1].hugepage_sz < \
					internal_config.hugepage_info[j].hugepage_sz)
				swap_hpi(&internal_config.hugepage_info[j-1],
						&internal_config.hugepage_info[j]);
	}

	/* now we have all info, check we have at least one valid size */
	for (i = 0; i < num_sizes; i++)
		if (internal_config.hugepage_info[i].hugedir != NULL &&
				internal_config.hugepage_info[i].num_pages > 0)
			return 0;
	/* no valid hugepage mounts available, return error */
	return -1;
}