1 files changed, 252 insertions, 0 deletions
diff --git a/schedutils/taskset.c b/schedutils/taskset.c
new file mode 100644
index 0000000..fe79cd6
--- /dev/null
+++ b/schedutils/taskset.c
@@ -0,0 +1,252 @@
+/*
+ * 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);
+	atexit(close_stdout);
+
+	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':
+			printf(UTIL_LINUX_VERSION);
+			return EXIT_SUCCESS;
+		case 'h':
+			usage();
+			break;
+		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;
+}