// SPDX-License-Identifier: GPL-2.0
#include <err.h>
#include <errno.h>
#include <stdio.h>
#include <stdlib.h>
#include <sys/prctl.h>

#include "futex.h"

#ifndef PR_FUTEX_HASH
#define PR_FUTEX_HASH                   78
# define PR_FUTEX_HASH_SET_SLOTS        1
# define PR_FUTEX_HASH_GET_SLOTS        2
#endif // PR_FUTEX_HASH

void futex_set_nbuckets_param(struct bench_futex_parameters *params)
{
        int ret;

        if (params->nbuckets < 0)
                return;

        ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_SET_SLOTS, params->nbuckets, 0);
        if (ret) {
                printf("Requesting %d hash buckets failed: %d/%m\n",
                       params->nbuckets, ret);
                err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)");
        }
}

void futex_print_nbuckets(struct bench_futex_parameters *params)
{
        char *futex_hash_mode;
        int ret;

        ret = prctl(PR_FUTEX_HASH, PR_FUTEX_HASH_GET_SLOTS);
        if (params->nbuckets >= 0) {
                if (ret != params->nbuckets) {
                        if (ret < 0) {
                                printf("Can't query number of buckets: %m\n");
                                err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)");
                        }
                        printf("Requested number of hash buckets does not currently used.\n");
                        printf("Requested: %d in usage: %d\n", params->nbuckets, ret);
                        err(EXIT_FAILURE, "prctl(PR_FUTEX_HASH)");
                }
                if (params->nbuckets == 0)
                        ret = asprintf(&futex_hash_mode, "Futex hashing: global hash");
                else
                        ret = asprintf(&futex_hash_mode, "Futex hashing: %d hash buckets",
                                       params->nbuckets);
        } else {
                if (ret <= 0) {
                        ret = asprintf(&futex_hash_mode, "Futex hashing: global hash");
                } else {
                        ret = asprintf(&futex_hash_mode, "Futex hashing: auto resized to %d buckets",
                                       ret);
                }
        }
        if (ret < 0)
                err(EXIT_FAILURE, "ENOMEM, futex_hash_mode");
        printf("%s\n", futex_hash_mode);
        free(futex_hash_mode);
}