/*
* taskset.c - set or retrieve 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, version 2, 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 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 <errno.h>
#include <sched.h>
#include <stddef.h>
#include <string.h>
#include "cpuset.h"
#include "nls.h"
#include "strutils.h"
#include "xalloc.h"
#include "procutils.h"
#include "c.h"
#include "closestream.h"
struct taskset {
pid_t pid; /* task PID */
cpu_set_t *set; /* task CPU mask */
size_t setsize;
char *buf; /* buffer for conversion from mask to string */
size_t buflen;
unsigned int use_list:1, /* use list rather than masks */
get_only:1; /* print the mask, but not modify */
};
static void __attribute__((__noreturn__)) usage(void)
{
FILE *out = stdout;
fprintf(out,
_("Usage: %s [options] [mask | cpu-list] [pid|cmd [args...]]\n\n"),
program_invocation_short_name);
fputs(USAGE_SEPARATOR, out);
fputs(_("Show or change the CPU affinity of a process.\n"), out);
fputs(USAGE_SEPARATOR, out);
fprintf(out, _(
"Options:\n"
" -a, --all-tasks operate on all the tasks (threads) for a given pid\n"
" -p, --pid operate on existing given pid\n"
" -c, --cpu-list display and specify cpus in list format\n"
));
printf(USAGE_HELP_OPTIONS(25));
fputs(USAGE_SEPARATOR, out);
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);
printf(USAGE_MAN_TAIL("taskset(1)"));
exit(EXIT_SUCCESS);
}
static void print_affinity(struct taskset *ts, int isnew)
{
char *str, *msg;
if (ts->use_list) {
str = cpulist_create(ts->buf, ts->buflen, ts->set, ts->setsize);
msg = isnew ? _("pid %d's new affinity list: %s\n") :
_("pid %d's current affinity list: %s\n");
} else {
str = cpumask_create(ts->buf, ts->buflen, ts->set, ts->setsize);
msg = isnew ? _("pid %d's new affinity mask: %s\n") :
_("pid %d's current affinity mask: %s\n");
}
if (!str)
errx(EXIT_FAILURE, _("internal error: conversion from cpuset to string failed"));
printf(msg, ts->pid ? ts->pid : getpid(), str);
}
static void __attribute__((__noreturn__)) err_affinity(pid_t pid, int set)
{
char *msg;
msg = set ? _("failed to set pid %d's affinity") :
_("failed to get pid %d's affinity");
err(EXIT_FAILURE, msg, pid ? pid : getpid());
}
static void do_taskset(struct taskset *ts, size_t setsize, cpu_set_t *set)
{
/* read the current mask */
if (ts->pid) {
if (sched_getaffinity(ts->pid, ts->setsize, ts->set) < 0)
err_affinity(ts->pid, 1);
print_affinity(ts, FALSE);
}
if (ts->get_only)
return;
/* set new mask */
if (sched_setaffinity(ts->pid, setsize, set) < 0)
err_affinity(ts->pid, 1);
/* re-read the current mask */
if (ts->pid) {
if (sched_getaffinity(ts->pid, ts->setsize, ts->set) < 0)
err_affinity(ts->pid, 0);
print_affinity(ts, TRUE);
}
}
int main(int argc, char **argv)
{
cpu_set_t *new_set;
pid_t pid = 0;
int c, all_tasks = 0;
int ncpus;
size_t new_setsize, nbits;
struct taskset ts;
static const struct option longopts[] = {
{ "all-tasks", 0, NULL, 'a' },
{ "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);
close_stdout_atexit();
memset(&ts, 0, sizeof(ts));
while ((c = getopt_long(argc, argv, "+apchV", longopts, NULL)) != -1) {
switch (c) {
case 'a':
all_tasks = 1;
break;
case 'p':
pid = strtos32_or_err(argv[argc - 1],
_("invalid PID argument"));
break;
case 'c':
ts.use_list = 1;
break;
case 'V':
print_version(EXIT_SUCCESS);
case 'h':
usage();
default:
errtryhelp(EXIT_FAILURE);
}
}
if ((!pid && argc - optind < 2)
|| (pid && (argc - optind < 1 || argc - optind > 2))) {
warnx(_("bad usage"));
errtryhelp(EXIT_FAILURE);
}
ncpus = get_max_number_of_cpus();
if (ncpus <= 0)
errx(EXIT_FAILURE, _("cannot determine NR_CPUS; aborting"));
/*
* the ts->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.
*/
ts.set = cpuset_alloc(ncpus, &ts.setsize, &nbits);
if (!ts.set)
err(EXIT_FAILURE, _("cpuset_alloc failed"));
/* buffer for conversion from mask to string */
ts.buflen = 7 * nbits;
ts.buf = xmalloc(ts.buflen);
/*
* 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 (argc - optind == 1)
ts.get_only = 1;
else if (ts.use_list) {
if (cpulist_parse(argv[optind], new_set, new_setsize, 0))
errx(EXIT_FAILURE, _("failed to parse CPU list: %s"),
argv[optind]);
} else if (cpumask_parse(argv[optind], new_set, new_setsize)) {
errx(EXIT_FAILURE, _("failed to parse CPU mask: %s"),
argv[optind]);
}
if (all_tasks && pid) {
struct proc_tasks *tasks = proc_open_tasks(pid);
while (!proc_next_tid(tasks, &ts.pid))
do_taskset(&ts, new_setsize, new_set);
proc_close_tasks(tasks);
} else {
ts.pid = pid;
do_taskset(&ts, new_setsize, new_set);
}
free(ts.buf);
cpuset_free(ts.set);
cpuset_free(new_set);
if (!pid) {
argv += optind + 1;
execvp(argv[0], argv);
errexec(argv[0]);
}
return EXIT_SUCCESS;
}
