LXR busybox/coreutils/nproc.c

   1/*
   2 * Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
   3 *
   4 * Licensed under GPLv2, see LICENSE in this source tree
   5 */
   6//config:config NPROC
   7//config:       bool "nproc (248 bytes)"
   8//config:       default y
   9//config:       help
  10//config:       Print number of CPUs
  11
  12//applet:IF_NPROC(APPLET_NOFORK(nproc, nproc, BB_DIR_USR_BIN, BB_SUID_DROP, nproc))
  13
  14//kbuild:lib-$(CONFIG_NPROC) += nproc.o
  15
  16//usage:#define nproc_trivial_usage
  17//usage:        ""
  18//TODO: "[--all] [--ignore=N]"
  19//usage:#define nproc_full_usage "\n\n"
  20//usage:        "Print number of CPUs"
  21
  22#include <sched.h>
  23#include "libbb.h"
  24
  25int nproc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  26int nproc_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
  27{
  28        unsigned long mask[1024];
  29        unsigned i, count = 0;
  30
  31        //getopt32(argv, "");
  32
  33        //if --all, count /sys/devices/system/cpu/cpuN dirs, else:
  34
  35        if (sched_getaffinity(0, sizeof(mask), (void*)mask) == 0) {
  36                for (i = 0; i < ARRAY_SIZE(mask); i++) {
  37                        unsigned long m = mask[i];
  38                        while (m) {
  39                                if (m & 1)
  40                                        count++;
  41                                m >>= 1;
  42                        }
  43                }
  44        }
  45        if (count == 0)
  46                count++;
  47        printf("%u\n", count);
  48
  49        return 0;
  50}
  51