system_cmds-597.1.1/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 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
  23 void
  24 usage(void)
  25 {
  26                 fprintf(stderr, "Usage: mean -[r|s|u] <pid>\n");
  27                 fprintf(stderr,  "\tLower <pid>'s priority.\n");
  28                 fprintf(stderr,  "\t-u: return <pid> to normal priority\n");
  29                 fprintf(stderr,  "\t-r: resume <pid>\n");
  30                 fprintf(stderr,  "\t-s: suspend <pid>\n");
  31                 exit(0);
  32 }
  33
  34 int
  35 main(int argc, char **argv)
  36 {
  37         int pid, err, i, ch;
  38         unsigned int count;
  39         mach_port_t task;
  40         thread_act_array_t threads;
  41         thread_precedence_policy_data_t policy;
  42
  43         boolean_t do_high = 0, do_resume = 0, do_suspend = 0;
  44         boolean_t do_low = 1;
  45
  46         if (argc < 2)
  47                 usage();
  48
  49         while ((ch = getopt(argc, argv, "rsu")) != -1)
  50         switch (ch) {
  51                 case 'u':
  52                         do_high = 1;
  53                         do_low = 0;
  54                         continue;
  55                 case 'r':
  56                         do_resume = 1;
  57                         do_low = 0;
  58                         continue;
  59                 case 's':
  60                         do_suspend = 1;
  61                         do_low = 0;
  62                         continue;
  63                 default:
  64                         usage();
  65         }
  66
  67         argc -= optind; argv += optind;
  68
  69         if (argc == 0)
  70                 usage();
  71
  72         pid = atoi(*argv);
  73         if (!pid)
  74                 usage();
  75
  76         err = task_for_pid(mach_task_self(), pid, &task);
  77         if (err) {
  78                 fprintf(stderr, "Failed to get task port (%d)\n", err);
  79                 exit(0);
  80         }
  81
  82         if (do_low || do_high) {
  83
  84                 err = task_threads(task, &threads, &count);
  85                 if (err) {
  86                         fprintf(stderr, "Failed to get thread list (%d)\n", err);
  87                         exit(0);
  88                 }
  89
  90                 if (do_low)
  91                         policy.importance = -100;
  92                 else
  93                         policy.importance = 0;
  94
  95                 for (i = 0; i < count; i++) {
  96                         err = thread_policy_set(threads[i],
  97                                         THREAD_PRECEDENCE_POLICY,
  98                                         (thread_policy_t) &policy,
  99                                         THREAD_PRECEDENCE_POLICY_COUNT);
 100                         if (err) {
 101                                 fprintf(stderr, "Failed to set thread priority (%d)\n", err);
 102                                 exit(0);
 103                         }
 104                 }
 105
 106                 printf("Process %d's threads set to %s priority.\n", pid,
 107                                 (do_low ? "lowest" : "highest"));
 108         }
 109
 110         if (do_suspend) {
 111                 err = task_suspend(task);
 112                 if (err) {
 113                         fprintf(stderr, "Failed to suspend task (%d)\n", err);
 114                 } else {
 115                         printf("Process %d suspended.\n", pid);
 116                 }
 117
 118         }
 119
 120         if (do_resume) {
 121                 err = task_resume(task);
 122                 if (err) {
 123                         fprintf(stderr, "Failed to resume task (%d)\n", err);
 124                 } else {
 125                         printf("Process %d resumed.\n", pid);
 126                 }
 127         }
 128
 129         return 0;
 130 }
 131