/*

 * Copyright (C) Internet Systems Consortium, Inc. ("ISC")

 *

 * SPDX-License-Identifier: MPL-2.0

 *

 * This Source Code Form is subject to the terms of the Mozilla Public

 * License, v. 2.0. If a copy of the MPL was not distributed with this

 * file, you can obtain one at https://mozilla.org/MPL/2.0/.

 *

 * See the COPYRIGHT file distributed with this work for additional

 * information regarding copyright ownership.

 */

#include <inttypes.h>

#include <sys/stat.h>

#include <isc/os.h>

#include <isc/types.h>

#include <isc/util.h>

#include <isc/uv.h>

#include "os_p.h"

static unsigned int isc__os_ncpus = 0;

static unsigned long isc__os_cacheline = ISC_OS_CACHELINE_SIZE;

static mode_t isc__os_umask = 0;

/*

 * The affinity support for non-Linux is in the review in the upstream

 * yet, but will be included in the upcoming version of libuv.

 */

#if (UV_VERSION_HEX >= UV_VERSION(1, 44, 0) && defined(__linux__)) || \

  UV_VERSION_HEX > UV_VERSION(1, 48, 0)

static void

ncpus_initialize(void) {

  isc__os_ncpus = uv_available_parallelism();

}

#else /* UV_VERSION_HEX >= UV_VERSION(1, 44, 0) */

#include <sys/param.h> /* for NetBSD */

#if HAVE_SYS_SYSCTL_H && !defined(__linux__)

#include <sys/sysctl.h>

#endif

#include <sys/types.h> /* for OpenBSD */

#include <unistd.h>

static int

sysconf_ncpus(void) {

  long ncpus = sysconf(_SC_NPROCESSORS_ONLN);

  return (int)ncpus;

}

#if HAVE_SYSCTLBYNAME

static int

sysctlbyname_ncpus(void) {

  int ncpu;

  size_t len = sizeof(ncpu);

  static const char *mib[] = {

    "hw.activecpu",

    "hw.logicalcpu",

    "hw.ncpu",

  };

  for (size_t i = 0; i < ARRAY_SIZE(mib); i++) {

    int r = sysctlbyname(mib[i], &ncpu, &len, NULL, 0);

    if (r != -1) {

      return ncpu;

    }

  }

  return -1;

}

#endif /* HAVE_SYSCTLBYNAME */

#if HAVE_SYS_SYSCTL_H && !defined(__linux__)

static int

sysctl_ncpus(void) {

  int ncpu;

  size_t len = sizeof(ncpu);

  static int mib[][2] = {

#ifdef HW_NCPUONLINE

    { CTL_HW, HW_NCPUONLINE },

#endif

    { CTL_HW, HW_NCPU },

  };

  for (size_t i = 0; i < ARRAY_SIZE(mib); i++) {

    int r = sysctl(mib[i], ARRAY_SIZE(mib[i]), &ncpu, &len, NULL,

             0);

    if (r != -1) {

      return ncpu;

    }

  }

  return -1;

}

#endif /* HAVE_SYS_SYSCTL_H */

#if defined(HAVE_SCHED_GETAFFINITY)

#include <sched.h>

/*

 * Administrators may wish to constrain the set of cores that BIND runs

 * on via the 'taskset' or 'numactl' programs (or equivalent on other

 * O/S), for example to achieve higher (or more stable) performance by

 * more closely associating threads with individual NIC rx queues. If

 * the admin has used taskset, it follows that BIND ought to

 * automatically use the given number of CPUs rather than the system

 * wide count.

 */

static int

sched_affinity_ncpus(void) {

  cpu_set_t cpus;

  int r = sched_getaffinity(0, sizeof(cpus), &cpus);

  if (r != -1) {

    return CPU_COUNT(&cpus);

  }

  return -1;

}

#endif

/*

 * Affinity detecting variant of sched_affinity_cpus() for FreeBSD

 */

#if defined(HAVE_CPUSET_GETAFFINITY)

#include <sys/cpuset.h>

#include <sys/param.h>

static int

cpuset_affinity_ncpus(void) {

  cpuset_t cpus;

  int r = cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_PID, -1,

           sizeof(cpus), &cpus);

  if (r != -1) {

    return CPU_COUNT(&cpus);

  }

  return -1;

}

#endif

static void

ncpus_initialize(void) {

#if defined(HAVE_CPUSET_GETAFFINITY)

  if (isc__os_ncpus <= 0) {

    isc__os_ncpus = cpuset_affinity_ncpus();

  }

#endif

#if defined(HAVE_SCHED_GETAFFINITY)

  if (isc__os_ncpus <= 0) {

    isc__os_ncpus = sched_affinity_ncpus();

  }

#endif

#if HAVE_SYSCTLBYNAME

  if (isc__os_ncpus <= 0) {

    isc__os_ncpus = sysctlbyname_ncpus();

  }

#endif

#if HAVE_SYS_SYSCTL_H && !defined(__linux__)

  if (isc__os_ncpus <= 0) {

    isc__os_ncpus = sysctl_ncpus();

  }

#endif

  if (isc__os_ncpus <= 0) {

    isc__os_ncpus = sysconf_ncpus();

  }

  if (isc__os_ncpus <= 0) {

    isc__os_ncpus = 1;

  }

}

#endif /* UV_VERSION_HEX >= UV_VERSION(1, 38, 0) */

static void

umask_initialize(void) {

  isc__os_umask = umask(0);

  (void)umask(isc__os_umask);

}

unsigned int

isc_os_ncpus(void) {

  return isc__os_ncpus;

}

unsigned long

isc_os_cacheline(void) {

  return isc__os_cacheline;

}

mode_t

isc_os_umask(void) {

  return isc__os_umask;

}

void

isc__os_initialize(void) {

  umask_initialize();

  ncpus_initialize();

#if defined(_SC_LEVEL1_DCACHE_LINESIZE)

  long s = sysconf(_SC_LEVEL1_DCACHE_LINESIZE);

  if (s > 0 && (unsigned long)s > isc__os_cacheline) {

    isc__os_cacheline = s;

  }

#endif

}

void

isc__os_shutdown(void) {

  /* empty, but defined for completeness */;

}