mean.tproj/mean.c

   1 /*
   2  *  mean.c
   3  *  mean - lower process priorities with more force than nice
   4  *
   5  *  Created by Lucia Ballard on 9/16/09.
   6  *  Copyright 2009-2016 Apple Inc. All rights reserved.
   7  *
   8  */
   9
  10 #include <mach/mach.h>
  11 #include <mach/task.h>
  12 #include <mach/thread_act.h>
  13 #include <mach/thread_policy.h>
  14
  15 #include <errno.h>
  16 #include <getopt.h>
  17 #include <stdio.h>
  18 #include <stdlib.h>
  19
  20 void usage(void);
  21
  22 void
  23 usage(void)
  24 {
  25                 fprintf(stderr, "Usage: mean -[r|s|u] <pid>\n");
  26                 fprintf(stderr,  "\tLower <pid>'s priority.\n");
  27                 fprintf(stderr,  "\t-u: return <pid> to normal priority\n");
  28                 fprintf(stderr,  "\t-r: resume <pid>\n");
  29                 fprintf(stderr,  "\t-s: suspend <pid>\n");
  30                 exit(0);
  31 }
  32
  33 int
  34 main(int argc, char **argv)
  35 {
  36         int pid, err, i, ch;
  37         unsigned int count;
  38         mach_port_t task;
  39         thread_act_array_t threads;
  40         thread_precedence_policy_data_t policy;
  41
  42         boolean_t do_high = 0, do_resume = 0, do_suspend = 0;
  43         boolean_t do_low = 1;
  44
  45         if (argc < 2)
  46                 usage();
  47
  48         while ((ch = getopt(argc, argv, "rsu")) != -1)
  49         switch (ch) {
  50                 case 'u':
  51                         do_high = 1;
  52                         do_low = 0;
  53                         continue;
  54                 case 'r':
  55                         do_resume = 1;
  56                         do_low = 0;
  57                         continue;
  58                 case 's':
  59                         do_suspend = 1;
  60                         do_low = 0;
  61                         continue;
  62                 default:
  63                         usage();
  64         }
  65
  66         argc -= optind; argv += optind;
  67
  68         if (argc == 0)
  69                 usage();
  70
  71         pid = atoi(*argv);
  72         if (!pid)
  73                 usage();
  74
  75         err = task_for_pid(mach_task_self(), pid, &task);
  76         if (err) {
  77                 fprintf(stderr, "Failed to get task port (%d)\n", err);
  78                 exit(0);
  79         }
  80
  81         if (do_low || do_high) {
  82
  83                 err = task_threads(task, &threads, &count);
  84                 if (err) {
  85                         fprintf(stderr, "Failed to get thread list (%d)\n", err);
  86                         exit(0);
  87                 }
  88
  89                 if (do_low)
  90                         policy.importance = -100;
  91                 else
  92                         policy.importance = 0;
  93
  94                 for (i = 0; i < count; i++) {
  95                         err = thread_policy_set(threads[i],
  96                                         THREAD_PRECEDENCE_POLICY,
  97                                         (thread_policy_t) &policy,
  98                                         THREAD_PRECEDENCE_POLICY_COUNT);
  99                         if (err) {
 100                                 fprintf(stderr, "Failed to set thread priority (%d)\n", err);
 101                                 exit(0);
 102                         }
 103                 }
 104
 105                 printf("Process %d's threads set to %s priority.\n", pid,
 106                                 (do_low ? "lowest" : "highest"));
 107         }
 108
 109         if (do_suspend) {
 110                 err = task_suspend(task);
 111                 if (err) {
 112                         fprintf(stderr, "Failed to suspend task (%d)\n", err);
 113                 } else {
 114                         printf("Process %d suspended.\n", pid);
 115                 }
 116         }
 117
 118         if (do_resume) {
 119                 err = task_resume(task);
 120                 if (err) {
 121                         fprintf(stderr, "Failed to resume task (%d)\n", err);
 122                 } else {
 123                         printf("Process %d resumed.\n", pid);
 124                 }
 125         }
 126
 127         return 0;
 128 }