sysdeps/mach/hurd/getpriority.c

   1 /* Copyright (C) 1994-2015 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 <limits.h>
  19 #include <hurd.h>
  20 #include <hurd/resource.h>
  21
  22 /* Return the highest priority of any process specified by WHICH and WHO
  23    (see <sys/resource.h>); if WHO is zero, the current process, process group,
  24    or user (as specified by WHO) is used.  A lower priority number means higher
  25    priority.  Priorities range from PRIO_MIN to PRIO_MAX.  */
  26 int
  27 __getpriority (enum __priority_which which, id_t who)
  28 {
  29   error_t err, onerr;
  30   int maxpri = INT_MIN;
  31   struct procinfo *pip;         /* Just for sizeof.  */
  32   int pibuf[sizeof *pip + 2 * sizeof (pip->threadinfos[0])], *pi = pibuf;
  33   size_t pisize = sizeof pibuf / sizeof pibuf[0];
  34
  35   error_t getonepriority (pid_t pid, struct procinfo *pip)
  36     {
  37       if (pip)
  38         onerr = 0;
  39       else
  40         {
  41           int *oldpi = pi;
  42           size_t oldpisize = pisize;
  43           char *tw = 0;
  44           size_t twsz = 0;
  45           int flags = PI_FETCH_TASKINFO;
  46           onerr = __USEPORT (PROC, __proc_getprocinfo (port, pid, &flags,
  47                                                        &pi, &pisize,
  48                                                        &tw, &twsz));
  49           if (twsz)
  50             __vm_deallocate (__mach_task_self (), (vm_address_t) tw, twsz);
  51           if (pi != oldpi && oldpi != pibuf)
  52             /* Old buffer from last call was not reused; free it.  */
  53             __vm_deallocate (__mach_task_self (),
  54                              (vm_address_t) oldpi, oldpisize * sizeof pi[0]);
  55           pip = (struct procinfo *) pi;
  56         }
  57 #ifdef TASK_SCHED_TIMESHARE_INFO
  58       if (!onerr && pip->timeshare_base_info.base_priority > maxpri)
  59         maxpri = pip->timeshare_base_info.base_priority;
  60 #else
  61       if (!onerr && pip->taskinfo.base_priority > maxpri)
  62         maxpri = pip->taskinfo.base_priority;
  63 #endif
  64       return 0;
  65     }
  66
  67   onerr = 0;
  68   err = _hurd_priority_which_map (which, who,
  69                                   getonepriority, PI_FETCH_TASKINFO);
  70
  71   if (pi != pibuf)
  72     __vm_deallocate (__mach_task_self (),
  73                      (vm_address_t) pi, pisize * sizeof pi[0]);
  74
  75   if (!err && maxpri == INT_MIN)
  76     /* No error, but no pids found.  */
  77     err = onerr ?: ESRCH;
  78
  79   if (err)
  80     return __hurd_fail (err);
  81
  82   return MACH_PRIORITY_TO_NICE (maxpri);
  83 }
  84 libc_hidden_def (__getpriority)
  85 weak_alias (__getpriority, getpriority)