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

#include <string.h>
#include <sys/types.h>
#include <sys/file.h>
#include <dirent.h>
#include <fcntl.h>
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <fnmatch.h>
#include <inttypes.h>
#include <stdarg.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mman.h>
#include <sys/queue.h>
#include <sys/stat.h>

#include <linux/mman.h> /* for hugetlb-related flags */

#include <rte_memory.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_private.h"
#include "eal_internal_cfg.h"
#include "eal_hugepages.h"
#include "eal_filesystem.h"

static const char sys_dir_path[] = "/sys/kernel/mm/hugepages";
static const char sys_pages_numa_dir_path[] = "/sys/devices/system/node";

/*
 * Uses mmap to create a shared memory area for storage of data
 * Used in this file to store the hugepage file map on disk
 */
static void *
map_shared_memory(const char *filename, const size_t mem_size, int flags)
{
        void *retval;
        int fd = open(filename, flags, 0600);
        if (fd < 0)
                return NULL;
        if (ftruncate(fd, mem_size) < 0) {
                close(fd);
                return NULL;
        }
        retval = mmap(NULL, mem_size, PROT_READ | PROT_WRITE,
                        MAP_SHARED, fd, 0);
        close(fd);
        return retval;
}

static void *
open_shared_memory(const char *filename, const size_t mem_size)
{
        return map_shared_memory(filename, mem_size, O_RDWR);
}

static void *
create_shared_memory(const char *filename, const size_t mem_size)
{
        return map_shared_memory(filename, mem_size, O_RDWR | O_CREAT);
}

static int get_hp_sysfs_value(const char *subdir, const char *file, unsigned long *val)
{
        char path[PATH_MAX];

        snprintf(path, sizeof(path), "%s/%s/%s",
                        sys_dir_path, subdir, file);
        return eal_parse_sysfs_value(path, val);
}

/* this function is only called from eal_hugepage_info_init which itself
 * is only called from a primary process */
static uint32_t
get_num_hugepages(const char *subdir, size_t sz)
{
        unsigned long resv_pages, num_pages, over_pages, surplus_pages;
        const char *nr_hp_file = "free_hugepages";
        const char *nr_rsvd_file = "resv_hugepages";
        const char *nr_over_file = "nr_overcommit_hugepages";
        const char *nr_splus_file = "surplus_hugepages";

        /* first, check how many reserved pages kernel reports */
        if (get_hp_sysfs_value(subdir, nr_rsvd_file, &resv_pages) < 0)
                return 0;

        if (get_hp_sysfs_value(subdir, nr_hp_file, &num_pages) < 0)
                return 0;

        if (get_hp_sysfs_value(subdir, nr_over_file, &over_pages) < 0)
                over_pages = 0;

        if (get_hp_sysfs_value(subdir, nr_splus_file, &surplus_pages) < 0)
                surplus_pages = 0;

        /* adjust num_pages */
        if (num_pages >= resv_pages)
                num_pages -= resv_pages;
        else if (resv_pages)
                num_pages = 0;

        if (over_pages >= surplus_pages)
                over_pages -= surplus_pages;
        else
                over_pages = 0;

        if (num_pages == 0 && over_pages == 0)
                RTE_LOG(WARNING, EAL, "No available %zu kB hugepages reported\n",
                                sz >> 10);

        num_pages += over_pages;
        if (num_pages < over_pages) /* overflow */
                num_pages = UINT32_MAX;

        /* we want to return a uint32_t and more than this looks suspicious
         * anyway ... */
        if (num_pages > UINT32_MAX)
                num_pages = UINT32_MAX;

        return num_pages;
}

static uint32_t
get_num_hugepages_on_node(const char *subdir, unsigned int socket, size_t sz)
{
        char path[PATH_MAX], socketpath[PATH_MAX];
        DIR *socketdir;
        unsigned long num_pages = 0;
        const char *nr_hp_file = "free_hugepages";

        snprintf(socketpath, sizeof(socketpath), "%s/node%u/hugepages",
                sys_pages_numa_dir_path, socket);

        socketdir = opendir(socketpath);
        if (socketdir) {
                /* Keep calm and carry on */
                closedir(socketdir);
        } else {
                /* Can't find socket dir, so ignore it */
                return 0;
        }

        snprintf(path, sizeof(path), "%s/%s/%s",
                        socketpath, subdir, nr_hp_file);
        if (eal_parse_sysfs_value(path, &num_pages) < 0)
                return 0;

        if (num_pages == 0)
                RTE_LOG(WARNING, EAL, "No free %zu kB hugepages reported on node %u\n",
                                sz >> 10, socket);

        /*
         * we want to return a uint32_t and more than this looks suspicious
         * anyway ...
         */
        if (num_pages > UINT32_MAX)
                num_pages = UINT32_MAX;

        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 int
get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
{
        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];
        int retval = -1;
        const struct internal_config *internal_conf =
                eal_get_internal_configuration();

        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_conf->hugepage_dir != NULL &&
                                strcmp(splitstr[MOUNTPT], internal_conf->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){
                                        strlcpy(hugedir, splitstr[MOUNTPT], len);
                                        retval = 0;
                                        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) {
                                        strlcpy(hugedir, splitstr[MOUNTPT], len);
                                        retval = 0;
                                        break;
                                }
                        }
                } /* end if strncmp hugetlbfs */
        } /* end while fgets */

        fclose(fd);
        return retval;
}

/*
 * Clear the hugepage directory of whatever hugepage files
 * there are. Checks if the file is locked (i.e.
 * if it's in use by another DPDK process).
 */
static int
clear_hugedir(const char * hugedir)
{
        DIR *dir;
        struct dirent *dirent;
        int dir_fd, fd, lck_result;
        const char filter[] = "*map_*"; /* matches hugepage files */

        /* open directory */
        dir = opendir(hugedir);
        if (!dir) {
                RTE_LOG(ERR, EAL, "Unable to open hugepage directory %s\n",
                                hugedir);
                goto error;
        }
        dir_fd = dirfd(dir);

        dirent = readdir(dir);
        if (!dirent) {
                RTE_LOG(ERR, EAL, "Unable to read hugepage directory %s\n",
                                hugedir);
                goto error;
        }

        while(dirent != NULL){
                /* skip files that don't match the hugepage pattern */
                if (fnmatch(filter, dirent->d_name, 0) > 0) {
                        dirent = readdir(dir);
                        continue;
                }

                /* try and lock the file */
                fd = openat(dir_fd, dirent->d_name, O_RDONLY);

                /* skip to next file */
                if (fd == -1) {
                        dirent = readdir(dir);
                        continue;
                }

                /* non-blocking lock */
                lck_result = flock(fd, LOCK_EX | LOCK_NB);

                /* if lock succeeds, remove the file */
                if (lck_result != -1)
                        unlinkat(dir_fd, dirent->d_name, 0);
                close (fd);
                dirent = readdir(dir);
        }

        closedir(dir);
        return 0;

error:
        if (dir)
                closedir(dir);

        RTE_LOG(ERR, EAL, "Error while clearing hugepage dir: %s\n",
                strerror(errno));

        return -1;
}

static int
compare_hpi(const void *a, const void *b)
{
        const struct hugepage_info *hpi_a = a;
        const struct hugepage_info *hpi_b = b;

        return hpi_b->hugepage_sz - hpi_a->hugepage_sz;
}

static void
calc_num_pages(struct hugepage_info *hpi, struct dirent *dirent)
{
        uint64_t total_pages = 0;
        unsigned int i;
        const struct internal_config *internal_conf =
                eal_get_internal_configuration();

        /*
         * first, try to put all hugepages into relevant sockets, but
         * if first attempts fails, fall back to collecting all pages
         * in one socket and sorting them later
         */
        total_pages = 0;
        /* we also don't want to do this for legacy init */
        if (!internal_conf->legacy_mem)
                for (i = 0; i < rte_socket_count(); i++) {
                        int socket = rte_socket_id_by_idx(i);
                        unsigned int num_pages =
                                        get_num_hugepages_on_node(
                                                dirent->d_name, socket,
                                                hpi->hugepage_sz);
                        hpi->num_pages[socket] = num_pages;
                        total_pages += num_pages;
                }
        /*
         * we failed to sort memory from the get go, so fall
         * back to old way
         */
        if (total_pages == 0) {
                hpi->num_pages[0] = get_num_hugepages(dirent->d_name,
                                hpi->hugepage_sz);

#ifndef RTE_ARCH_64
                /* for 32-bit systems, limit number of hugepages to
                 * 1GB per page size */
                hpi->num_pages[0] = RTE_MIN(hpi->num_pages[0],
                                RTE_PGSIZE_1G / hpi->hugepage_sz);
#endif
        }
}

static int
hugepage_info_init(void)
{       const char dirent_start_text[] = "hugepages-";
        const size_t dirent_start_len = sizeof(dirent_start_text) - 1;
        unsigned int i, num_sizes = 0;
        DIR *dir;
        struct dirent *dirent;
        struct internal_config *internal_conf =
                eal_get_internal_configuration();

        dir = opendir(sys_dir_path);
        if (dir == NULL) {
                RTE_LOG(ERR, EAL,
                        "Cannot open directory %s to read system hugepage info\n",
                        sys_dir_path);
                return -1;
        }

        for (dirent = readdir(dir); dirent != NULL; dirent = readdir(dir)) {
                struct hugepage_info *hpi;

                if (strncmp(dirent->d_name, dirent_start_text,
                            dirent_start_len) != 0)
                        continue;

                if (num_sizes >= MAX_HUGEPAGE_SIZES)
                        break;

                hpi = &internal_conf->hugepage_info[num_sizes];
                hpi->hugepage_sz =
                        rte_str_to_size(&dirent->d_name[dirent_start_len]);

                /* first, check if we have a mountpoint */
                if (get_hugepage_dir(hpi->hugepage_sz,
                        hpi->hugedir, sizeof(hpi->hugedir)) < 0) {
                        uint32_t num_pages;

                        num_pages = get_num_hugepages(dirent->d_name,
                                        hpi->hugepage_sz);
                        if (num_pages > 0)
                                RTE_LOG(NOTICE, EAL,
                                        "%" PRIu32 " hugepages of size "
                                        "%" PRIu64 " reserved, but no mounted "
                                        "hugetlbfs found for that size\n",
                                        num_pages, hpi->hugepage_sz);
                        /* if we have kernel support for reserving hugepages
                         * through mmap, and we're in in-memory mode, treat this
                         * page size as valid. we cannot be in legacy mode at
                         * this point because we've checked this earlier in the
                         * init process.
                         */
#ifdef MAP_HUGE_SHIFT
                        if (internal_conf->in_memory) {
                                RTE_LOG(DEBUG, EAL, "In-memory mode enabled, "
                                        "hugepages of size %" PRIu64 " bytes "
                                        "will be allocated anonymously\n",
                                        hpi->hugepage_sz);
                                calc_num_pages(hpi, dirent);
                                num_sizes++;
                        }
#endif
                        continue;
                }

                /* try to obtain a writelock */
                hpi->lock_descriptor = open(hpi->hugedir, O_RDONLY);

                /* if blocking lock failed */
                if (flock(hpi->lock_descriptor, LOCK_EX) == -1) {
                        RTE_LOG(CRIT, EAL,
                                "Failed to lock hugepage directory!\n");
                        break;
                }
                /* clear out the hugepages dir from unused pages */
                if (clear_hugedir(hpi->hugedir) == -1)
                        break;

                calc_num_pages(hpi, dirent);

                num_sizes++;
        }
        closedir(dir);

        /* something went wrong, and we broke from the for loop above */
        if (dirent != NULL)
                return -1;

        internal_conf->num_hugepage_sizes = num_sizes;

        /* sort the page directory entries by size, largest to smallest */
        qsort(&internal_conf->hugepage_info[0], num_sizes,
              sizeof(internal_conf->hugepage_info[0]), compare_hpi);

        /* now we have all info, check we have at least one valid size */
        for (i = 0; i < num_sizes; i++) {
                /* pages may no longer all be on socket 0, so check all */
                unsigned int j, num_pages = 0;
                struct hugepage_info *hpi = &internal_conf->hugepage_info[i];

                for (j = 0; j < RTE_MAX_NUMA_NODES; j++)
                        num_pages += hpi->num_pages[j];
                if (num_pages > 0)
                        return 0;
        }

        /* no valid hugepage mounts available, return error */
        return -1;
}

/*
 * when we initialize the hugepage info, everything goes
 * to socket 0 by default. it will later get sorted by memory
 * initialization procedure.
 */
int
eal_hugepage_info_init(void)
{
        struct hugepage_info *hpi, *tmp_hpi;
        unsigned int i;
        struct internal_config *internal_conf =
                eal_get_internal_configuration();

        if (hugepage_info_init() < 0)
                return -1;

        /* for no shared files mode, we're done */
        if (internal_conf->no_shconf)
                return 0;

        hpi = &internal_conf->hugepage_info[0];

        tmp_hpi = create_shared_memory(eal_hugepage_info_path(),
                        sizeof(internal_conf->hugepage_info));
        if (tmp_hpi == NULL) {
                RTE_LOG(ERR, EAL, "Failed to create shared memory!\n");
                return -1;
        }

        memcpy(tmp_hpi, hpi, sizeof(internal_conf->hugepage_info));

        /* we've copied file descriptors along with everything else, but they
         * will be invalid in secondary process, so overwrite them
         */
        for (i = 0; i < RTE_DIM(internal_conf->hugepage_info); i++) {
                struct hugepage_info *tmp = &tmp_hpi[i];
                tmp->lock_descriptor = -1;
        }

        if (munmap(tmp_hpi, sizeof(internal_conf->hugepage_info)) < 0) {
                RTE_LOG(ERR, EAL, "Failed to unmap shared memory!\n");
                return -1;
        }
        return 0;
}

int eal_hugepage_info_read(void)
{
        struct internal_config *internal_conf =
                eal_get_internal_configuration();
        struct hugepage_info *hpi = &internal_conf->hugepage_info[0];
        struct hugepage_info *tmp_hpi;

        tmp_hpi = open_shared_memory(eal_hugepage_info_path(),
                                  sizeof(internal_conf->hugepage_info));
        if (tmp_hpi == NULL) {
                RTE_LOG(ERR, EAL, "Failed to open shared memory!\n");
                return -1;
        }

        memcpy(hpi, tmp_hpi, sizeof(internal_conf->hugepage_info));

        if (munmap(tmp_hpi, sizeof(internal_conf->hugepage_info)) < 0) {
                RTE_LOG(ERR, EAL, "Failed to unmap shared memory!\n");
                return -1;
        }
        return 0;
}