xref: /titanic_52/usr/src/lib/libbc/libc/compat/sys5/nice.c (revision fb3fb4f3d76d55b64440afd0af72775dfad3bd1d)
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 }
73