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/*
* mean.c
* mean - lower process priorities with more force than nice
*
* Created by Lucia Ballard on 9/16/09.
* Copyright 2009-2016 Apple Inc. All rights reserved.
*
*/
#include <mach/mach.h>
#include <mach/task.h>
#include <mach/thread_act.h>
#include <mach/thread_policy.h>
#include <errno.h>
#include <getopt.h>
#include <stdio.h>
#include <stdlib.h>
void usage(void);
void
usage(void)
{
fprintf(stderr, "Usage: mean -[r|s|u] <pid>\n");
fprintf(stderr, "\tLower <pid>'s priority.\n");
fprintf(stderr, "\t-u: return <pid> to normal priority\n");
fprintf(stderr, "\t-r: resume <pid>\n");
fprintf(stderr, "\t-s: suspend <pid>\n");
exit(0);
}
int
main(int argc, char **argv)
{
int pid, err, i, ch;
unsigned int count;
mach_port_t task;
thread_act_array_t threads;
thread_precedence_policy_data_t policy;
boolean_t do_high = 0, do_resume = 0, do_suspend = 0;
boolean_t do_low = 1;
if (argc < 2)
usage();
while ((ch = getopt(argc, argv, "rsu")) != -1)
switch (ch) {
case 'u':
do_high = 1;
do_low = 0;
continue;
case 'r':
do_resume = 1;
do_low = 0;
continue;
case 's':
do_suspend = 1;
do_low = 0;
continue;
default:
usage();
}
argc -= optind; argv += optind;
if (argc == 0)
usage();
pid = atoi(*argv);
if (!pid)
usage();
err = task_for_pid(mach_task_self(), pid, &task);
if (err) {
fprintf(stderr, "Failed to get task port (%d)\n", err);
exit(0);
}
if (do_low || do_high) {
err = task_threads(task, &threads, &count);
if (err) {
fprintf(stderr, "Failed to get thread list (%d)\n", err);
exit(0);
}
if (do_low)
policy.importance = -100;
else
policy.importance = 0;
for (i = 0; i < count; i++) {
err = thread_policy_set(threads[i],
THREAD_PRECEDENCE_POLICY,
(thread_policy_t) &policy,
THREAD_PRECEDENCE_POLICY_COUNT);
if (err) {
fprintf(stderr, "Failed to set thread priority (%d)\n", err);
exit(0);
}
}
printf("Process %d's threads set to %s priority.\n", pid,
(do_low ? "lowest" : "highest"));
}
if (do_suspend) {
err = task_suspend(task);
if (err) {
fprintf(stderr, "Failed to suspend task (%d)\n", err);
} else {
printf("Process %d suspended.\n", pid);
}
}
if (do_resume) {
err = task_resume(task);
if (err) {
fprintf(stderr, "Failed to resume task (%d)\n", err);
} else {
printf("Process %d resumed.\n", pid);
}
}
return 0;
}
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