sysdeps/mach/hurd/getpriority.c

   1 /* Copyright (C) 1994, 1995, 1996 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
  16 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  17 Cambridge, MA 02139, USA.  */
  18
  19 #include <limits.h>
  20 #include <hurd.h>
  21 #include <hurd/resource.h>
  22
  23 /* Return the highest priority of any process specified by WHICH and WHO
  24    (see <sys/resource.h>); if WHO is zero, the current process, process group,
  25    or user (as specified by WHO) is used.  A lower priority number means higher
  26    priority.  Priorities range from PRIO_MIN to PRIO_MAX.  */
  27 int
  28 getpriority (enum __priority_which which, int who)
  29 {
  30   error_t err, onerr;
  31   int maxpri = INT_MIN;
  32   struct procinfo *pip;         /* Just for sizeof.  */
  33   int pibuf[sizeof *pip + 2 * sizeof (pip->threadinfos[0])], *pi = pibuf;
  34   unsigned int pisize = sizeof pibuf / sizeof pibuf[0];
  35
  36   error_t getonepriority (pid_t pid, struct procinfo *pip)
  37     {
  38       if (pip)
  39         onerr = 0;
  40       else
  41         {
  42           int *oldpi = pi;
  43           unsigned int oldpisize = pisize;
  44           char *tw = 0;
  45           size_t twsz = 0;
  46           int flags = PI_FETCH_TASKINFO;
  47           onerr = __USEPORT (PROC, __proc_getprocinfo (port, pid, &flags,
  48                                                        &pi, &pisize,
  49                                                        &tw, &twsz));
  50           if (twsz)
  51             __vm_deallocate (__mach_task_self (), (vm_address_t) tw, twsz);
  52           if (pi != oldpi && oldpi != pibuf)
  53             /* Old buffer from last call was not reused; free it.  */
  54             __vm_deallocate (__mach_task_self (),
  55                              (vm_address_t) oldpi, oldpisize * sizeof pi[0]);
  56           pip = (struct procinfo *) pi;
  57         }
  58       if (!onerr && pip->taskinfo.base_priority > maxpri)
  59         maxpri = pip->taskinfo.base_priority;
  60       return 0;
  61     }
  62
  63   onerr = 0;
  64   err = _hurd_priority_which_map (which, who,
  65                                   getonepriority, PI_FETCH_TASKINFO);
  66
  67   if (pi != pibuf)
  68     __vm_deallocate (__mach_task_self (),
  69                      (vm_address_t) pi, pisize * sizeof pi[0]);
  70
  71   if (!err && maxpri == INT_MIN)
  72     /* No error, but no pids found.  */
  73     err = onerr ?: ESRCH;
  74
  75   if (err)
  76     return __hurd_fail (err);
  77
  78   return MACH_PRIORITY_TO_NICE (maxpri);
  79 }