1 /*
2 * taskset.c - set or retrieve a task's CPU affinity
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License, version 2, as
6 * published by the Free Software Foundation
7 *
8 * This program is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License along
14 * with this program; if not, write to the Free Software Foundation, Inc.,
15 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
16 *
17 * Copyright (C) 2004 Robert Love
18 * Copyright (C) 2010 Karel Zak <kzak@redhat.com>
19 */
20
21 #include <stdio.h>
22 #include <stdlib.h>
23 #include <unistd.h>
24 #include <getopt.h>
25 #include <errno.h>
26 #include <sched.h>
27 #include <stddef.h>
28 #include <string.h>
29
30 #include "cpuset.h"
31 #include "nls.h"
32 #include "strutils.h"
33 #include "xalloc.h"
34 #include "procutils.h"
35 #include "c.h"
36 #include "closestream.h"
37
38 struct taskset {
39 pid_t pid; /* task PID */
40 cpu_set_t *set; /* task CPU mask */
41 size_t setsize;
42 char *buf; /* buffer for conversion from mask to string */
43 size_t buflen;
44 unsigned int use_list:1, /* use list rather than masks */
45 get_only:1; /* print the mask, but not modify */
46 };
47
usage(void)48 static void __attribute__((__noreturn__)) usage(void)
49 {
50 FILE *out = stdout;
51 fprintf(out,
52 _("Usage: %s [options] [mask | cpu-list] [pid|cmd [args...]]\n\n"),
53 program_invocation_short_name);
54
55 fputs(USAGE_SEPARATOR, out);
56 fputs(_("Show or change the CPU affinity of a process.\n"), out);
57 fputs(USAGE_SEPARATOR, out);
58
59 fprintf(out, _(
60 "Options:\n"
61 " -a, --all-tasks operate on all the tasks (threads) for a given pid\n"
62 " -p, --pid operate on existing given pid\n"
63 " -c, --cpu-list display and specify cpus in list format\n"
64 ));
65 printf(USAGE_HELP_OPTIONS(25));
66
67 fputs(USAGE_SEPARATOR, out);
68 fprintf(out, _(
69 "The default behavior is to run a new command:\n"
70 " %1$s 03 sshd -b 1024\n"
71 "You can retrieve the mask of an existing task:\n"
72 " %1$s -p 700\n"
73 "Or set it:\n"
74 " %1$s -p 03 700\n"
75 "List format uses a comma-separated list instead of a mask:\n"
76 " %1$s -pc 0,3,7-11 700\n"
77 "Ranges in list format can take a stride argument:\n"
78 " e.g. 0-31:2 is equivalent to mask 0x55555555\n"),
79 program_invocation_short_name);
80
81 printf(USAGE_MAN_TAIL("taskset(1)"));
82 exit(EXIT_SUCCESS);
83 }
84
print_affinity(struct taskset * ts,int isnew)85 static void print_affinity(struct taskset *ts, int isnew)
86 {
87 char *str, *msg;
88
89 if (ts->use_list) {
90 str = cpulist_create(ts->buf, ts->buflen, ts->set, ts->setsize);
91 msg = isnew ? _("pid %d's new affinity list: %s\n") :
92 _("pid %d's current affinity list: %s\n");
93 } else {
94 str = cpumask_create(ts->buf, ts->buflen, ts->set, ts->setsize);
95 msg = isnew ? _("pid %d's new affinity mask: %s\n") :
96 _("pid %d's current affinity mask: %s\n");
97 }
98
99 if (!str)
100 errx(EXIT_FAILURE, _("internal error: conversion from cpuset to string failed"));
101
102 printf(msg, ts->pid ? ts->pid : getpid(), str);
103 }
104
err_affinity(pid_t pid,int set)105 static void __attribute__((__noreturn__)) err_affinity(pid_t pid, int set)
106 {
107 char *msg;
108
109 msg = set ? _("failed to set pid %d's affinity") :
110 _("failed to get pid %d's affinity");
111
112 err(EXIT_FAILURE, msg, pid ? pid : getpid());
113 }
114
do_taskset(struct taskset * ts,size_t setsize,cpu_set_t * set)115 static void do_taskset(struct taskset *ts, size_t setsize, cpu_set_t *set)
116 {
117 /* read the current mask */
118 if (ts->pid) {
119 if (sched_getaffinity(ts->pid, ts->setsize, ts->set) < 0)
120 err_affinity(ts->pid, 1);
121 print_affinity(ts, FALSE);
122 }
123
124 if (ts->get_only)
125 return;
126
127 /* set new mask */
128 if (sched_setaffinity(ts->pid, setsize, set) < 0)
129 err_affinity(ts->pid, 1);
130
131 /* re-read the current mask */
132 if (ts->pid) {
133 if (sched_getaffinity(ts->pid, ts->setsize, ts->set) < 0)
134 err_affinity(ts->pid, 0);
135 print_affinity(ts, TRUE);
136 }
137 }
138
main(int argc,char ** argv)139 int main(int argc, char **argv)
140 {
141 cpu_set_t *new_set;
142 pid_t pid = 0;
143 int c, all_tasks = 0;
144 int ncpus;
145 size_t new_setsize, nbits;
146 struct taskset ts;
147
148 static const struct option longopts[] = {
149 { "all-tasks", 0, NULL, 'a' },
150 { "pid", 0, NULL, 'p' },
151 { "cpu-list", 0, NULL, 'c' },
152 { "help", 0, NULL, 'h' },
153 { "version", 0, NULL, 'V' },
154 { NULL, 0, NULL, 0 }
155 };
156
157 setlocale(LC_ALL, "");
158 bindtextdomain(PACKAGE, LOCALEDIR);
159 textdomain(PACKAGE);
160 close_stdout_atexit();
161
162 memset(&ts, 0, sizeof(ts));
163
164 while ((c = getopt_long(argc, argv, "+apchV", longopts, NULL)) != -1) {
165 switch (c) {
166 case 'a':
167 all_tasks = 1;
168 break;
169 case 'p':
170 pid = strtos32_or_err(argv[argc - 1],
171 _("invalid PID argument"));
172 break;
173 case 'c':
174 ts.use_list = 1;
175 break;
176
177 case 'V':
178 print_version(EXIT_SUCCESS);
179 case 'h':
180 usage();
181 default:
182 errtryhelp(EXIT_FAILURE);
183 }
184 }
185
186 if ((!pid && argc - optind < 2)
187 || (pid && (argc - optind < 1 || argc - optind > 2))) {
188 warnx(_("bad usage"));
189 errtryhelp(EXIT_FAILURE);
190 }
191
192 ncpus = get_max_number_of_cpus();
193 if (ncpus <= 0)
194 errx(EXIT_FAILURE, _("cannot determine NR_CPUS; aborting"));
195
196 /*
197 * the ts->set is always used for the sched_getaffinity call
198 * On the sched_getaffinity the kernel demands a user mask of
199 * at least the size of its own cpumask_t.
200 */
201 ts.set = cpuset_alloc(ncpus, &ts.setsize, &nbits);
202 if (!ts.set)
203 err(EXIT_FAILURE, _("cpuset_alloc failed"));
204
205 /* buffer for conversion from mask to string */
206 ts.buflen = 7 * nbits;
207 ts.buf = xmalloc(ts.buflen);
208
209 /*
210 * new_set is always used for the sched_setaffinity call
211 * On the sched_setaffinity the kernel will zero-fill its
212 * cpumask_t if the user's mask is shorter.
213 */
214 new_set = cpuset_alloc(ncpus, &new_setsize, NULL);
215 if (!new_set)
216 err(EXIT_FAILURE, _("cpuset_alloc failed"));
217
218 if (argc - optind == 1)
219 ts.get_only = 1;
220
221 else if (ts.use_list) {
222 if (cpulist_parse(argv[optind], new_set, new_setsize, 0))
223 errx(EXIT_FAILURE, _("failed to parse CPU list: %s"),
224 argv[optind]);
225 } else if (cpumask_parse(argv[optind], new_set, new_setsize)) {
226 errx(EXIT_FAILURE, _("failed to parse CPU mask: %s"),
227 argv[optind]);
228 }
229
230 if (all_tasks && pid) {
231 struct proc_tasks *tasks = proc_open_tasks(pid);
232 while (!proc_next_tid(tasks, &ts.pid))
233 do_taskset(&ts, new_setsize, new_set);
234 proc_close_tasks(tasks);
235 } else {
236 ts.pid = pid;
237 do_taskset(&ts, new_setsize, new_set);
238 }
239
240 free(ts.buf);
241 cpuset_free(ts.set);
242 cpuset_free(new_set);
243
244 if (!pid) {
245 argv += optind + 1;
246 execvp(argv[0], argv);
247 errexec(argv[0]);
248 }
249
250 return EXIT_SUCCESS;
251 }
252