busybox/coreutils/nproc.c

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/*
* Copyright (C) 2017 Denys Vlasenko <vda.linux@googlemail.com>
*
* Licensed under GPLv2, see LICENSE in this source tree
*/
//config:config NPROC
//config: bool "nproc (248 bytes)"
//config: default y
//config: help
//config: Print number of CPUs
//applet:IF_NPROC(APPLET_NOFORK(nproc, nproc, BB_DIR_USR_BIN, BB_SUID_DROP, nproc))
//kbuild:lib-$(CONFIG_NPROC) += nproc.o
//usage:#define nproc_trivial_usage
//usage: ""IF_LONG_OPTS("--all --ignore=N")
//usage:#define nproc_full_usage "\n\n"
//usage: "Print number of available CPUs"
//usage: IF_LONG_OPTS(
//usage: "\n"
//usage: "\n --all Number of installed CPUs"
//usage: "\n --ignore=N Exclude N CPUs"
//usage: )
#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];
int count = 0;
#if ENABLE_LONG_OPTS
int ignore = 0;
int opts = getopt32long(argv, "\xfe:+",
"ignore\0" Required_argument "\xfe"
"all\0" No_argument "\xff"
, &ignore
);
if (opts & (1 << 1)) {
DIR *cpusd = opendir("/sys/devices/system/cpu");
if (cpusd) {
struct dirent *de;
while (NULL != (de = readdir(cpusd))) {
char *cpuid = strstr(de->d_name, "cpu");
if (cpuid && isdigit(cpuid[strlen(cpuid) - 1]))
count++;
}
closedir(cpusd);
}
} else
#endif
if (sched_getaffinity(0, sizeof(mask), (void*)mask) == 0) {
int i;
for (i = 0; i < ARRAY_SIZE(mask); i++) {
unsigned long m = mask[i];
while (m) {
if (m & 1)
count++;
m >>= 1;
}
}
}
IF_LONG_OPTS(count -= ignore;)
if (count <= 0)
count = 1;
printf("%u\n", count);
return 0;
}