/*
* taskset.c - command-line utility for setting and retrieving
* a task's CPU affinity
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License, v2, as
* published by the Free Software Foundation
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Copyright (C) 2004 Robert Love
* Copyright (C) 2010 Karel Zak <kzak@redhat.com>
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <sched.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <sys/syscall.h>
#include <err.h>
#include "cpuset.h"
#include "nls.h"
static void __attribute__((__noreturn__)) usage(FILE *out)
{
fprintf(out,
_("Usage: %s [options] [mask | cpu-list] [pid|cmd [args...]]\n\n"),
program_invocation_short_name);
fprintf(out, _(
"Options:\n"
" -p, --pid operate on existing given pid\n"
" -c, --cpu-list display and specify cpus in list format\n"
" -h, --help display this help\n"
" -V, --version output version information\n\n"));
fprintf(out, _(
"The default behavior is to run a new command:\n"
" %1$s 03 sshd -b 1024\n"
"You can retrieve the mask of an existing task:\n"
" %1$s -p 700\n"
"Or set it:\n"
" %1$s -p 03 700\n"
"List format uses a comma-separated list instead of a mask:\n"
" %1$s -pc 0,3,7-11 700\n"
"Ranges in list format can take a stride argument:\n"
" e.g. 0-31:2 is equivalent to mask 0x55555555\n"),
program_invocation_short_name);
fprintf(out, _("\nFor more information see taskset(1).\n"));
exit(out == stderr ? EXIT_FAILURE : EXIT_SUCCESS);
}
/*
* Number of bits in a CPU bitmask on current system
*/
static int max_number_of_cpus(void)
{
int n, cpus = 2048;
size_t setsize;
cpu_set_t *set = cpuset_alloc(cpus, &setsize, NULL);
if (!set)
goto err;
for (;;) {
CPU_ZERO_S(setsize, set);
/* the library version does not return size of cpumask_t */
n = syscall(SYS_sched_getaffinity, 0, setsize, set);
if (n < 0 && errno == EINVAL && cpus < 1024 * 1024) {
cpuset_free(set);
cpus *= 2;
set = cpuset_alloc(cpus, &setsize, NULL);
if (!set)
goto err;
continue;
}
cpuset_free(set);
return n * 8;
}
err:
errx(EXIT_FAILURE, _("cannot determine NR_CPUS; aborting"));
return 0;
}
int main(int argc, char *argv[])
{
cpu_set_t *new_set, *cur_set;
pid_t pid = 0;
int opt, c_opt = 0, rc;
char *buf;
unsigned int ncpus;
size_t new_setsize, cur_setsize, cur_nbits, buflen;
struct option longopts[] = {
{ "pid", 0, NULL, 'p' },
{ "cpu-list", 0, NULL, 'c' },
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ NULL, 0, NULL, 0 }
};
setlocale(LC_ALL, "");
bindtextdomain(PACKAGE, LOCALEDIR);
textdomain(PACKAGE);
while ((opt = getopt_long(argc, argv, "+pchV", longopts, NULL)) != -1) {
switch (opt) {
case 'p':
pid = atoi(argv[argc - 1]);
break;
case 'c':
c_opt = 1;
break;
case 'V':
printf("taskset (%s)\n", PACKAGE_STRING);
return EXIT_SUCCESS;
case 'h':
usage(stdout);
break;
default:
usage(stderr);
break;
}
}
if ((!pid && argc - optind < 2)
|| (pid && (argc - optind < 1 || argc - optind > 2)))
usage(stderr);
ncpus = max_number_of_cpus();
/*
* cur_set is always used for the sched_getaffinity call
* On the sched_getaffinity the kernel demands a user mask of
* at least the size of its own cpumask_t.
*/
cur_set = cpuset_alloc(ncpus, &cur_setsize, &cur_nbits);
if (!cur_set)
err(EXIT_FAILURE, _("cpuset_alloc failed"));
buflen = 7 * cur_nbits;
buf = malloc(buflen);
if (!buf)
err(EXIT_FAILURE, _("malloc failed"));
/*
* new_set is always used for the sched_setaffinity call
* On the sched_setaffinity the kernel will zero-fill its
* cpumask_t if the user's mask is shorter.
*/
new_set = cpuset_alloc(ncpus, &new_setsize, NULL);
if (!new_set)
err(EXIT_FAILURE, _("cpuset_alloc failed"));
if (pid) {
if (sched_getaffinity(pid, cur_setsize, cur_set) < 0)
err(EXIT_FAILURE, _("failed to get pid %d's affinity"), pid);
if (c_opt)
printf(_("pid %d's current affinity list: %s\n"), pid,
cpulist_create(buf, buflen, cur_set, cur_setsize));
else
printf(_("pid %d's current affinity mask: %s\n"), pid,
cpumask_create(buf, buflen, cur_set, cur_setsize));
if (argc - optind == 1)
return EXIT_SUCCESS;
}
rc = c_opt ? cpulist_parse(argv[optind], new_set, new_setsize) :
cpumask_parse(argv[optind], new_set, new_setsize);
if (rc)
errx(EXIT_FAILURE, _("failed to parse %s %s"),
c_opt ? _("CPU list") : _("CPU mask"),
argv[optind]);
if (sched_setaffinity(pid, new_setsize, new_set) < 0)
err(EXIT_FAILURE, _("failed to set pid %d's affinity"), pid);
if (sched_getaffinity(pid, cur_setsize, cur_set) < 0)
err(EXIT_FAILURE, _("failed to get pid %d's affinity"), pid);
if (pid) {
if (c_opt)
printf(_("pid %d's new affinity list: %s\n"), pid,
cpulist_create(buf, buflen, cur_set, cur_setsize));
else
printf(_("pid %d's new affinity mask: %s\n"), pid,
cpumask_create(buf, buflen, cur_set, cur_setsize));
}
free(buf);
cpuset_free(cur_set);
cpuset_free(new_set);
if (!pid) {
argv += optind + 1;
execvp(argv[0], argv);
err(EXIT_FAILURE, _("executing %s failed"), argv[0]);
}
return EXIT_SUCCESS;
}
