usr/src/lib/libbc/libc/compat/sys5/nice.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1986 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28           /* from UCB 4.1 83/05/30 */
  29
  30 #include <sys/time.h>
  31 #include <sys/resource.h>
  32 #include <errno.h>
  33
  34 /*
  35  * Backwards compatible nice.
  36  */
  37 int
  38 nice(incr)
  39         int incr;
  40 {
  41         register int prio;
  42         int serrno;
  43
  44         /* put in brain-damaged upper range checking */
  45         if ((incr > 40) && (geteuid() != 0)) {
  46                 errno = EPERM;
  47                 return (-1);
  48         }
  49
  50         serrno = errno;
  51         errno = 0;
  52         prio = getpriority(PRIO_PROCESS, 0);
  53         if (prio == -1 && errno)
  54                 return (-1);
  55         prio += incr;
  56         if (prio < -20)
  57                 prio = -20;
  58         else if (prio > 19)
  59                 prio = 19;
  60         if (setpriority(PRIO_PROCESS, 0, prio) == -1) {
  61                 /*
  62                  * 4.3BSD stupidly returns EACCES on an attempt by a
  63                  * non-super-user process to lower a priority; map
  64                  * it to EPERM.
  65                  */
  66                 if (errno == EACCES)
  67                         errno = EPERM;
  68                 return (-1);
  69         }
  70         errno = serrno;
  71         return (prio);
  72 }