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 (3.9 kb)"
   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:        ""IF_LONG_OPTS("[--all] [--ignore=N]")
  18 //usage:#define nproc_full_usage "\n\n"
  19 //usage:        "Print number of available CPUs"
  20 //usage:        IF_LONG_OPTS(
  21 //usage:     "\n"
  22 //usage:     "\n        --all           Number of installed CPUs"
  23 //usage:     "\n        --ignore=N      Exclude N CPUs"
  24 //usage:        )
  25
  26 #include "libbb.h"
  27
  28 int nproc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  29 int nproc_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
  30 {
  31         int count = 0;
  32 #if ENABLE_LONG_OPTS
  33         int ignore = 0;
  34         int opts = getopt32long(argv, "\xfe:+",
  35                         "ignore\0" Required_argument "\xfe"
  36                         "all\0"    No_argument       "\xff"
  37                         , &ignore
  38         );
  39
  40         if (opts & (1 << 1)) {
  41                 DIR *cpusd = opendir("/sys/devices/system/cpu");
  42                 if (cpusd) {
  43                         struct dirent *de;
  44                         while (NULL != (de = readdir(cpusd))) {
  45                                 char *cpuid = strstr(de->d_name, "cpu");
  46                                 if (cpuid && isdigit(cpuid[strlen(cpuid) - 1]))
  47                                         count++;
  48                         }
  49                         IF_FEATURE_CLEAN_UP(closedir(cpusd);)
  50                 }
  51         } else
  52 #endif
  53         {
  54                 int i;
  55                 unsigned sz = 2 * 1024;
  56                 unsigned long *mask = get_malloc_cpu_affinity(0, &sz);
  57                 sz /= sizeof(long);
  58                 for (i = 0; i < sz; i++) {
  59                         if (mask[i] != 0) /* most mask[i] are usually 0 */
  60                                 count += bb_popcnt_long(mask[i]);
  61                 }
  62                 IF_FEATURE_CLEAN_UP(free(mask);)
  63         }
  64
  65         IF_LONG_OPTS(count -= ignore;)
  66         if (count <= 0)
  67                 count = 1;
  68
  69         printf("%u\n", count);
  70
  71         return 0;
  72 }