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root/usr/lib/posix/process/setpriority.c

DEFINITIONS

1. setpriority

   1 /*
   2  * Copyright (c) 2007, Kohsuke Ohtani
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  * 3. Neither the name of the author nor the names of any co-contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  30 #include <sys/prex.h>
  31 #include <sys/posix.h>
  32 #include <ipc/proc.h>
  33 #include <sys/resource.h>
  35 #include <stddef.h>
  36 #include <unistd.h>
  37 #include <errno.h>
  39 /*
  40  * setpriority - set priority for process or process group.
  41  *
  42  * Note: support only for current process.
  43  */
  44 int
setpriority(int which, int who, int pri)
  46 {
  47         int error, val;
  49         switch (which) {
  50         case PRIO_PROCESS:
  51         case PRIO_PGRP:
  52                 if (who != 0) {
errno = EPERM;
  54                         return -1;
  55                 }
  56                 break;
  57         case PRIO_USER:
  58                 if (who != 1) {
errno = EPERM;
  60                         return -1;
  61                 }
  62                 break;
  63         default:
errno = EINVAL;
  65                 return -1;
  66         }
  68         if (pri < MINPRI)
pri = MINPRI;
  70         if (pri > MAXPRI)
pri = MAXPRI;
val = PRI_DEFAULT + pri;
error = thread_setpri(thread_self(), val);
  76         if (error) {
errno = error;
  78                 return -1;
  79         }
  80         return 0;
  81 }