sysdeps/mach/hurd/setpriority.c

   1 /* Copyright (C) 1994, 1995, 1997 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 Library General Public License as
   6    published by the Free Software Foundation; either version 2 of the
   7    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    Library General Public License for more details.
  13
  14    You should have received a copy of the GNU Library General Public
  15    License along with the GNU C Library; see the file COPYING.LIB.  If not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include <hurd.h>
  20 #include <hurd/resource.h>
  21
  22 /* Set the priority of all processes specified by WHICH and WHO
  23    to PRIO.  Returns 0 on success, -1 on errors.  */
  24 int
  25 setpriority (enum __priority_which which, int who, int prio)
  26 {
  27   error_t err;
  28   error_t pidloser, priloser;
  29   unsigned int npids, ntasks, nwin, nperm, nacces;
  30
  31   error_t setonepriority (pid_t pid, struct procinfo *pi)
  32     {
  33       task_t task;
  34       error_t piderr = __USEPORT (PROC, __proc_pid2task (port, pid, &task));
  35       if (piderr == EPERM)
  36         ++nperm;
  37       if (piderr != ESRCH)
  38         {
  39           ++npids;
  40           if (piderr && piderr != EPERM)
  41             pidloser = piderr;
  42         }
  43       if (! piderr)
  44         {
  45           error_t prierr;
  46           ++ntasks;
  47           prierr = __task_priority (task, NICE_TO_MACH_PRIORITY (prio), 1);
  48           __mach_port_deallocate (__mach_task_self (), task);
  49           switch (prierr)
  50             {
  51             case KERN_FAILURE:
  52               ++nacces;
  53               break;
  54             case KERN_SUCCESS:
  55               ++nwin;
  56               break;
  57             case KERN_INVALID_ARGUMENT: /* Task died.  */
  58               --npids;
  59               --ntasks;
  60               break;
  61             default:
  62               priloser = prierr;
  63             }
  64         }
  65       return 0;
  66     }
  67
  68   npids = ntasks = nwin = nperm = nacces = 0;
  69   pidloser = priloser = 0;
  70   err = _hurd_priority_which_map (which, who, setonepriority, 0);
  71
  72   if (!err && npids == 0)
  73     /* No error, but no pids found.  */
  74     err = ESRCH;
  75   else if (nperm == npids)
  76     /* Got EPERM from proc_task2pid for every process.  */
  77     err = EPERM;
  78   else if (nacces == ntasks)
  79     /* Got KERN_FAILURE from task_priority for every task.  */
  80     err = EACCES;
  81   else if (nwin == 0)
  82     err = pidloser ?: priloser;
  83
  84   return err ? __hurd_fail (err) : 0;
  85 }