/*

 *   This program is is free software; you can redistribute it and/or modify

 *   it under the terms of the GNU General Public License, version 2 of the

 *   License as published by the Free Software Foundation.

 *

 *   This program is distributed in the hope that it will be useful,

 *   but WITHOUT ANY WARRANTY; without even the implied warranty of

 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 *   GNU General Public License for more details.

 *

 *   You should have received a copy of the GNU General Public License

 *   along with this program; if not, write to the Free Software

 *   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA

 */

/** Functions for getting information about the system architecture

 *

 * @file src/lib/util/hw.c

 *

 * @author Arran Cudbard-Bell (a.cudbardb@freeradius.org)

 * @copyright 2020 Arran Cudbard-Bell (a.cudbardb@freeradius.org)

 */

#define CACHE_LINE_DEFAULT  128

#define CORES_DEFAULT   1

#include <freeradius-devel/util/hw.h>

#include <freeradius-devel/util/syserror.h>

#include <freeradius-devel/util/strerror.h>

#if defined(__APPLE__) || defined(__FreeBSD__)

#include <sys/sysctl.h>

size_t fr_hw_cache_line_size(void)

{

  size_t cache_line_size    = CACHE_LINE_DEFAULT;

  size_t cache_line_size_len  = sizeof(cache_line_size);

  sysctlbyname("hw.cachelinesize", &cache_line_size, &cache_line_size_len, 0, 0);

  return cache_line_size;

}

uint32_t fr_hw_num_cores_active(void)

{

  uint32_t num_cores    = CORES_DEFAULT;

  size_t num_cores_len    = sizeof(num_cores);

  sysctlbyname("hw.physicalcpu", &num_cores, &num_cores_len, 0, 0);

  return num_cores;

}

#elif defined(__linux__)

#include <stdio.h>

#include <unistd.h>

size_t fr_hw_cache_line_size(void)

{

  FILE *file      = NULL;

  unsigned int cache_line_size  = CACHE_LINE_DEFAULT;

  file = fopen("/sys/devices/system/cpu/cpu0/cache/index0/coherency_cache_line_size", "r");

  if (file) {

    if (fscanf(file, "%d", &cache_line_size) != 1) {

      cache_line_size = CACHE_LINE_DEFAULT;

    }

    fclose(file);

  }

  return cache_line_size;

}

uint32_t fr_hw_num_cores_active(void)

{

  uint32_t lcores = 0, tsibs = 0;

  char buff[32];

  char path[64];

  for (lcores = 0;;lcores++) {

    FILE *cpu;

    snprintf(path, sizeof(path), "/sys/devices/system/cpu/cpu%u/topology/thread_siblings_list", lcores);

    cpu = fopen(path, "r");

    if (!cpu) break;

    while (fscanf(cpu, "%[0-9]", buff)) {

      tsibs++;

      if (fgetc(cpu) != ',') break;

    }

    fclose(cpu);

  }

  /*

   *  Catch Linux weirdness.

   *

   *  You'd think this would be enough to quiet clang scan,

   *  but it's not.

   */

  if (unlikely((tsibs == 0) || (lcores == 0) || (lcores > tsibs))) {

    fr_strerror_printf("Failed retrieving cpu topology info: %s", fr_syserror(errno));

    return 0;

  }

#ifdef STATIC_ANALYZER

  /*

   *  Prevent static analyzer from warning about divide by zero

   */

  if ((tsibs / lcores) == 0) return 0;

#endif

  return lcores / (tsibs / lcores);

}

#else

size_t fr_hw_cache_line_size(void)

{

  return CACHE_LINE_DEFAULT;

}

uint32_t fr_hw_num_cores_active(void)

{

  return CORES_DEFAULT;

}

#endif