sysdeps/mach/hurd/setpriority.c

   1 /* Copyright (C) 1994-2017 Free Software Foundation, Inc.
   2    This file is part of the GNU C Library.
   3
   4    The GNU C Library is free software; you can redistribute it and/or
   5    modify it under the terms of the GNU Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the License, or (at your option) any later version.
   8
   9    The GNU C Library is distributed in the hope that it will be useful,
  10    but WITHOUT ANY WARRANTY; without even the implied warranty of
  11    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, see
  16    <http://www.gnu.org/licenses/>.  */
  17
  18 #include <hurd.h>
  19 #include <hurd/resource.h>
  20
  21 /* Set the priority of all processes specified by WHICH and WHO
  22    to PRIO.  Returns 0 on success, -1 on errors.  */
  23 int
  24 __setpriority (enum __priority_which which, id_t who, int prio)
  25 {
  26   error_t err;
  27   error_t pidloser, priloser;
  28   unsigned int npids, ntasks, nwin, nperm, nacces;
  29
  30   error_t setonepriority (pid_t pid, struct procinfo *pi)
  31     {
  32       task_t task;
  33       error_t piderr = __USEPORT (PROC, __proc_pid2task (port, pid, &task));
  34       if (piderr == EPERM)
  35         ++nperm;
  36       if (piderr != ESRCH)
  37         {
  38           ++npids;
  39           if (piderr && piderr != EPERM)
  40             pidloser = piderr;
  41         }
  42       if (! piderr)
  43         {
  44           error_t prierr;
  45           ++ntasks;
  46 #ifdef POLICY_TIMESHARE_BASE_COUNT
  47           {
  48             /* XXX This assumes timeshare policy.  */
  49             struct policy_timeshare_base base
  50               = { NICE_TO_MACH_PRIORITY (prio) };
  51             prierr = __task_policy (task, POLICY_TIMESHARE,
  52                                     (policy_base_t) &base,
  53                                     POLICY_TIMESHARE_BASE_COUNT,
  54                                     0, 1);
  55           }
  56 #else
  57           prierr = __task_priority (task, NICE_TO_MACH_PRIORITY (prio), 1);
  58 #endif
  59           __mach_port_deallocate (__mach_task_self (), task);
  60           switch (prierr)
  61             {
  62             case KERN_FAILURE:
  63               ++nacces;
  64               break;
  65             case KERN_SUCCESS:
  66               ++nwin;
  67               break;
  68             case KERN_INVALID_ARGUMENT: /* Task died.  */
  69               --npids;
  70               --ntasks;
  71               break;
  72             default:
  73               priloser = prierr;
  74             }
  75         }
  76       return 0;
  77     }
  78
  79   npids = ntasks = nwin = nperm = nacces = 0;
  80   pidloser = priloser = 0;
  81   err = _hurd_priority_which_map (which, who, setonepriority, 0);
  82
  83   if (!err && npids == 0)
  84     /* No error, but no pids found.  */
  85     err = ESRCH;
  86   else if (nperm == npids)
  87     /* Got EPERM from proc_task2pid for every process.  */
  88     err = EPERM;
  89   else if (nacces == ntasks)
  90     /* Got KERN_FAILURE from task_priority for every task.  */
  91     err = EACCES;
  92   else if (nwin == 0)
  93     err = pidloser ?: priloser;
  94
  95   return err ? __hurd_fail (err) : 0;
  96 }
  97 libc_hidden_def (__setpriority)
  98 weak_alias (__setpriority, setpriority)