busybox/coreutils/nproc.c
Denys Vlasenko 87ae0fe095 nproc: new applet
function                                             old     new   delta
nproc_main                                             -      98     +98
applet_names                                        2584    2590      +6
applet_main                                         1496    1500      +4
applet_install_loc                                   187     188      +1

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-04-07 21:47:53 +02:00

52 lines
1.1 KiB
C

/*
* Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
*
* Licensed under GPLv2, see LICENSE in this source tree
*/
//config:config NPROC
//config: bool "nproc"
//config: default y
//config: help
//config: Print number of CPUs
//applet:IF_NPROC(APPLET(nproc, BB_DIR_USR_BIN, BB_SUID_DROP))
//kbuild:lib-$(CONFIG_NPROC) += nproc.o
//usage:#define nproc_trivial_usage
//usage: ""
//TODO: "[--all] [--ignore=N]"
//usage:#define nproc_full_usage "\n\n"
//usage: "Print number of CPUs"
#include <sched.h>
#include "libbb.h"
int nproc_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int nproc_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
{
unsigned long mask[1024];
unsigned i, count = 0;
//applet_long_options = ...;
//getopt32(argv, "");
//if --all, count /sys/devices/system/cpu/cpuN dirs, else:
if (sched_getaffinity(0, sizeof(mask), (void*)mask) == 0) {
for (i = 0; i < ARRAY_SIZE(mask); i++) {
unsigned long m = mask[i];
while (m) {
if (m & 1)
count++;
m >>= 1;
}
}
}
if (count == 0)
count++;
printf("%u\n", count);
return 0;
}