src/nproc.c

   1 /* nproc - print the number of processors.
   2    Copyright (C) 2009-2024 Free Software Foundation, Inc.
   3
   4    This program is free software: you can redistribute it and/or modify
   5    it under the terms of the GNU General Public License as published by
   6    the Free Software Foundation, either version 3 of the License, or
   7    (at your option) any later version.
   8
   9    This program is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12    GNU General Public License for more details.
  13
  14    You should have received a copy of the GNU General Public License
  15    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  16
  17 /* Written by Giuseppe Scrivano.  */
  18
  19 #include <config.h>
  20 #include <getopt.h>
  21 #include <stdio.h>
  22 #include <sys/types.h>
  23
  24 #include "system.h"
  25 #include "nproc.h"
  26 #include "quote.h"
  27 #include "xdectoint.h"
  28
  29 /* The official name of this program (e.g., no 'g' prefix).  */
  30 #define PROGRAM_NAME "nproc"
  31
  32 #define AUTHORS proper_name ("Giuseppe Scrivano")
  33
  34 enum
  35 {
  36   ALL_OPTION = CHAR_MAX + 1,
  37   IGNORE_OPTION
  38 };
  39
  40 static struct option const longopts[] =
  41 {
  42   {"all", no_argument, nullptr, ALL_OPTION},
  43   {"ignore", required_argument, nullptr, IGNORE_OPTION},
  44   {GETOPT_HELP_OPTION_DECL},
  45   {GETOPT_VERSION_OPTION_DECL},
  46   {nullptr, 0, nullptr, 0}
  47 };
  48
  49 void
  50 usage (int status)
  51 {
  52   if (status != EXIT_SUCCESS)
  53     emit_try_help ();
  54   else
  55     {
  56       printf (_("Usage: %s [OPTION]...\n"), program_name);
  57       fputs (_("\
  58 Print the number of processing units available to the current process,\n\
  59 which may be less than the number of online processors\n\
  60 \n\
  61 "), stdout);
  62       fputs (_("\
  63       --all      print the number of installed processors\n\
  64       --ignore=N  if possible, exclude N processing units\n\
  65 "), stdout);
  66
  67       fputs (HELP_OPTION_DESCRIPTION, stdout);
  68       fputs (VERSION_OPTION_DESCRIPTION, stdout);
  69       emit_ancillary_info (PROGRAM_NAME);
  70     }
  71   exit (status);
  72 }
  73
  74 int
  75 main (int argc, char **argv)
  76 {
  77   unsigned long nproc, ignore = 0;
  78   initialize_main (&argc, &argv);
  79   set_program_name (argv[0]);
  80   setlocale (LC_ALL, "");
  81   bindtextdomain (PACKAGE, LOCALEDIR);
  82   textdomain (PACKAGE);
  83
  84   atexit (close_stdout);
  85
  86   enum nproc_query mode = NPROC_CURRENT_OVERRIDABLE;
  87
  88   while (true)
  89     {
  90       int c = getopt_long (argc, argv, "", longopts, nullptr);
  91       if (c == -1)
  92         break;
  93       switch (c)
  94         {
  95         case_GETOPT_HELP_CHAR;
  96
  97         case_GETOPT_VERSION_CHAR (PROGRAM_NAME, AUTHORS);
  98
  99         case ALL_OPTION:
 100           mode = NPROC_ALL;
 101           break;
 102
 103         case IGNORE_OPTION:
 104           ignore = xnumtoumax (optarg, 10, 0, ULONG_MAX, "",
 105                                _("invalid number"), 0, XTOINT_MAX_QUIET);
 106           break;
 107
 108         default:
 109           usage (EXIT_FAILURE);
 110         }
 111     }
 112
 113   if (argc != optind)
 114     {
 115       error (0, 0, _("extra operand %s"), quote (argv[optind]));
 116       usage (EXIT_FAILURE);
 117     }
 118
 119   nproc = num_processors (mode);
 120
 121   if (ignore < nproc)
 122     nproc -= ignore;
 123   else
 124     nproc = 1;
 125
 126   printf ("%lu\n", nproc);
 127
 128   return EXIT_SUCCESS;
 129 }