/*
* taskset.c - taskset
* Command-line utility for setting and retrieving a task's CPU affinity
*
* Robert Love <rml@tech9.net> 25 April 2002
*
* Linux kernels as of 2.5.8 provide the needed syscalls for
* working with a task's cpu affinity. Currently 2.4 does not
* support these syscalls, but patches are available at:
*
* http://www.kernel.org/pub/linux/kernel/people/rml/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
*/
#define _GNU_SOURCE
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <getopt.h>
#include <sched.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
static void show_usage(const char *cmd)
{
fprintf(stderr, "taskset version " VERSION "\n");
fprintf(stderr, "usage: %s [options] [mask | cpu-list] [pid |"\
" cmd [args...]]\n", cmd);
fprintf(stderr, "set or get the affinity of a process\n\n");
fprintf(stderr, " -p, --pid "
"operate on existing given pid\n");
fprintf(stderr, " -c, --cpu-list "\
"display and specify cpus in list format\n");
fprintf(stderr, " -h, --help display this help\n");
fprintf(stderr, " -v, --version "\
"output version information\n\n");
fprintf(stderr, "The default behavior is to run a new command:\n");
fprintf(stderr, " %s 03 sshd -b 1024\n", cmd);
fprintf(stderr, "You can retrieve the mask of an existing task:\n");
fprintf(stderr, " %s -p 700\n", cmd);
fprintf(stderr, "Or set it:\n");
fprintf(stderr, " %s -p 03 700\n", cmd);
fprintf(stderr, "List format uses a comma-separated list instead"\
" of a mask:\n");
fprintf(stderr, " %s -pc 0,3,7-11 700\n", cmd);
fprintf(stderr, "Ranges in list format can take a stride argument:\n");
fprintf(stderr, " e.g. 0-31:2 is equivalent to mask 0x55555555\n\n");
}
static inline int val_to_char(int v)
{
if (v >= 0 && v < 10)
return '0' + v;
else if (v >= 10 && v < 16)
return ('a' - 10) + v;
else
return -1;
}
static char * cpuset_to_str(cpu_set_t *mask, char *str)
{
int base;
char *ptr = str;
char *ret = 0;
for (base = CPU_SETSIZE - 4; base >= 0; base -= 4) {
char val = 0;
if (CPU_ISSET(base, mask))
val |= 1;
if (CPU_ISSET(base + 1, mask))
val |= 2;
if (CPU_ISSET(base + 2, mask))
val |= 4;
if (CPU_ISSET(base + 3, mask))
val |= 8;
if (!ret && val)
ret = ptr;
*ptr++ = val_to_char(val);
}
*ptr = 0;
return ret ? ret : ptr - 1;
}
static char * cpuset_to_cstr(cpu_set_t *mask, char *str)
{
int i;
char *ptr = str;
int entry_made = 0;
for (i = 0; i < CPU_SETSIZE; i++) {
if (CPU_ISSET(i, mask)) {
int j;
int run = 0;
entry_made = 1;
for (j = i + 1; j < CPU_SETSIZE; j++) {
if (CPU_ISSET(j, mask))
run++;
else
break;
}
if (!run)
sprintf(ptr, "%d,", i);
else if (run == 1) {
sprintf(ptr, "%d,%d,", i, i + 1);
i++;
} else {
sprintf(ptr, "%d-%d,", i, i + run);
i += run;
}
while (*ptr != 0)
ptr++;
}
}
ptr -= entry_made;
*ptr = 0;
return str;
}
static inline int char_to_val(int c)
{
int cl;
cl = tolower(c);
if (c >= '0' && c <= '9')
return c - '0';
else if (cl >= 'a' && cl <= 'f')
return cl + (10 - 'a');
else
return -1;
}
static int str_to_cpuset(cpu_set_t *mask, const char* str)
{
int len = strlen(str);
const char *ptr = str + len - 1;
int base = 0;
/* skip 0x, it's all hex anyway */
if (len > 1 && !memcmp(str, "0x", 2L))
str += 2;
CPU_ZERO(mask);
while (ptr >= str) {
char val = char_to_val(*ptr);
if (val == (char) -1)
return -1;
if (val & 1)
CPU_SET(base, mask);
if (val & 2)
CPU_SET(base + 1, mask);
if (val & 4)
CPU_SET(base + 2, mask);
if (val & 8)
CPU_SET(base + 3, mask);
len--;
ptr--;
base += 4;
}
return 0;
}
static const char *nexttoken(const char *q, int sep)
{
if (q)
q = strchr(q, sep);
if (q)
q++;
return q;
}
static int cstr_to_cpuset(cpu_set_t *mask, const char* str)
{
const char *p, *q;
q = str;
CPU_ZERO(mask);
while (p = q, q = nexttoken(q, ','), p) {
unsigned int a; /* beginning of range */
unsigned int b; /* end of range */
unsigned int s; /* stride */
const char *c1, *c2;
if (sscanf(p, "%u", &a) < 1)
return 1;
b = a;
s = 1;
c1 = nexttoken(p, '-');
c2 = nexttoken(p, ',');
if (c1 != NULL && (c2 == NULL || c1 < c2)) {
if (sscanf(c1, "%u", &b) < 1)
return 1;
c1 = nexttoken(c1, ':');
if (c1 != NULL && (c2 == NULL || c1 < c2))
if (sscanf(c1, "%u", &s) < 1) {
return 1;
}
}
if (!(a <= b))
return 1;
while (a <= b) {
CPU_SET(a, mask);
a += s;
}
}
return 0;
}
int main(int argc, char *argv[])
{
cpu_set_t new_mask, cur_mask;
pid_t pid = 0;
int opt, err;
char mstr[1 + CPU_SETSIZE / 4];
char cstr[7 * CPU_SETSIZE];
int c_opt = 0;
struct option longopts[] = {
{ "pid", 0, NULL, 'p' },
{ "cpu-list", 0, NULL, 'c' },
{ "help", 0, NULL, 'h' },
{ "version", 0, NULL, 'V' },
{ NULL, 0, NULL, 0 }
};
while ((opt = getopt_long(argc, argv, "+pchV", longopts, NULL)) != -1) {
int ret = 1;
switch (opt) {
case 'p':
pid = atoi(argv[argc - 1]);
break;
case 'c':
c_opt = 1;
break;
case 'V':
printf("taskset version " VERSION "\n");
return 0;
case 'h':
ret = 0;
default:
show_usage(argv[0]);
return ret;
}
}
if ((!pid && argc - optind < 2)
|| (pid && (argc - optind < 1 || argc - optind > 2))) {
show_usage(argv[0]);
return 1;
}
if (pid) {
if (sched_getaffinity(pid, sizeof (cur_mask), &cur_mask) < 0) {
perror("sched_getaffinity");
fprintf(stderr, "failed to get pid %d's affinity\n",
pid);
return 1;
}
if (c_opt)
printf("pid %d's current affinity list: %s\n", pid,
cpuset_to_cstr(&cur_mask, cstr));
else
printf("pid %d's current affinity mask: %s\n", pid,
cpuset_to_str(&cur_mask, mstr));
if (argc - optind == 1)
return 0;
}
if (c_opt)
err = cstr_to_cpuset(&new_mask, argv[optind]);
else
err = str_to_cpuset(&new_mask, argv[optind]);
if (err) {
if (c_opt)
fprintf(stderr, "failed to parse CPU list %s\n",
argv[optind]);
else
fprintf(stderr, "failed to parse CPU mask %s\n",
argv[optind]);
return 1;
}
if (sched_setaffinity(pid, sizeof (new_mask), &new_mask)) {
perror("sched_setaffinity");
fprintf(stderr, "failed to set pid %d's affinity.\n", pid);
return 1;
}
if (sched_getaffinity(pid, sizeof (cur_mask), &cur_mask) < 0) {
perror("sched_getaffinity");
fprintf(stderr, "failed to get pid %d's affinity.\n", pid);
return 1;
}
if (pid) {
if (c_opt)
printf("pid %d's new affinity list: %s\n", pid,
cpuset_to_cstr(&cur_mask, cstr));
else
printf("pid %d's new affinity mask: %s\n", pid,
cpuset_to_str(&cur_mask, mstr));
} else {
argv += optind + 1;
execvp(argv[0], argv);
perror("execvp");
fprintf(stderr, "failed to execute %s\n", argv[0]);
return 1;
}
return 0;
}
