gen/FreeBSD/nice.c

   1 /*
   2  * Copyright (c) 1983, 1993
   3  *      The Regents of the University of California.  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  * 4. Neither the name of the University nor the names of its 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 REGENTS 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 REGENTS 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  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "@(#)nice.c      8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/gen/nice.c,v 1.4 2007/01/09 00:27:54 imp Exp $");
  35
  36 #include <sys/types.h>
  37 #include <sys/time.h>
  38 #include <sys/resource.h>
  39 #include <errno.h>
  40 #include <unistd.h>
  41 #if __DARWIN_UNIX03
  42 #include <limits.h>
  43 #endif /* __DARWIN_UNIX03 */
  44 /*
  45  * Backwards compatible nice.
  46  */
  47 int
  48 nice(incr)
  49         int incr;
  50 {
  51         int prio, rv;
  52
  53         errno = 0;
  54         prio = getpriority(PRIO_PROCESS, 0);
  55         if (prio == -1 && errno)
  56                 return (-1);
  57 #if __DARWIN_UNIX03
  58         if (prio + incr > NZERO-1)
  59                 incr = NZERO-1-prio;
  60 #endif /* __DARWIN_UNIX03 */
  61         rv = setpriority(PRIO_PROCESS, 0, prio + incr);
  62         if (rv == -1 && errno == EACCES)
  63                 errno = EPERM;
  64         return (rv == -1) ? rv : getpriority(PRIO_PROCESS, 0);
  65 }