133 lines
2.5 KiB
C
133 lines
2.5 KiB
C
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/*-
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* Copyright (c) 2023 Mateusz Guzik
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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/*
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* This program is intended to be compatible with nproc as found in GNU
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* coreutils.
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*
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* In order to maintain that, do not add any features here if they are not
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* present in said program. If you are looking for anything more advanced you
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* probably should patch cpuset(1) instead.
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*/
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#include <sys/param.h>
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#include <sys/cpuset.h>
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#include <err.h>
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#include <errno.h>
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#include <getopt.h>
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#include <limits.h>
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#include <stdbool.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <sysexits.h>
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#include <unistd.h>
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#define OPT_ALL (CHAR_MAX + 1)
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#define OPT_IGNORE (CHAR_MAX + 2)
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#define OPT_VERSION (CHAR_MAX + 3)
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#define OPT_HELP (CHAR_MAX + 4)
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static struct option long_opts[] = {
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{ "all", no_argument, NULL, OPT_ALL },
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{ "ignore", required_argument, NULL, OPT_IGNORE },
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{ "version", no_argument, NULL, OPT_VERSION },
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{ "help", no_argument, NULL, OPT_HELP },
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{ NULL, 0, NULL, 0 }
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};
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static void
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help(void)
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{
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fprintf(stderr,
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"usage: nproc [--all] [--ignore=count]\n");
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fprintf(stderr,
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" nproc --help\n");
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fprintf(stderr,
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" nproc --version\n");
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}
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static void
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usage(void)
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{
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help();
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exit(EX_USAGE);
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}
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/*
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* GNU variant ships with the --version switch.
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*
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* While we don't have anything to put there, print something which is
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* whitespace-compatible with the original. Version number was taken
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* from coreutils this code is in sync with.
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*/
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static void
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version(void)
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{
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printf("nproc (neither_GNU nor_coreutils) 8.32\n");
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exit(EXIT_SUCCESS);
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}
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int
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main(int argc, char *argv[])
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{
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const char *errstr;
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cpuset_t mask;
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int ch, cpus, ignore;
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bool all_flag;
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ignore = 0;
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all_flag = false;
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while ((ch = getopt_long(argc, argv, "", long_opts, NULL)) != -1) {
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switch (ch) {
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case OPT_ALL:
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all_flag = true;
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break;
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case OPT_IGNORE:
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ignore = strtonum(optarg, 0, INT_MAX, &errstr);
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if (errstr)
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errx(1, "bad ignore count: %s", errstr);
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break;
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case OPT_VERSION:
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version();
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__builtin_unreachable();
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case OPT_HELP:
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help();
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exit(EXIT_SUCCESS);
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default:
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usage();
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}
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}
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argc -= optind;
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argv += optind;
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if (argc != 0)
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usage();
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if (all_flag) {
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cpus = sysconf(_SC_NPROCESSORS_ONLN);
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if (cpus == -1)
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err(1, "sysconf");
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} else {
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CPU_ZERO(&mask);
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if (cpuset_getaffinity(CPU_LEVEL_WHICH, CPU_WHICH_TID, -1,
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sizeof(mask), &mask) != 0)
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err(1, "cpuset_getaffinity");
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cpus = CPU_COUNT(&mask);
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}
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if (ignore >= cpus)
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cpus = 1;
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else
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cpus -= ignore;
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printf("%u\n", cpus);
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exit(EXIT_SUCCESS);
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}
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