xref: /illumos-gate/usr/src/lib/libc/port/gen/setpriority.c (revision 71269a2275bf5a143dad6461eee2710a344e7261)
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 (the "License").
6  * You may not use this file except in compliance with the License.
7  *
8  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
9  * or http://www.opensolaris.org/os/licensing.
10  * See the License for the specific language governing permissions
11  * and limitations under the License.
12  *
13  * When distributing Covered Code, include this CDDL HEADER in each
14  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
15  * If applicable, add the following below this CDDL HEADER, with the
16  * fields enclosed by brackets "[]" replaced with your own identifying
17  * information: Portions Copyright [yyyy] [name of copyright owner]
18  *
19  * CDDL HEADER END
20  */
21 
22 /*
23  * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
24  * Use is subject to license terms.
25  */
26 
27 /*	Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T	*/
28 /*	  All Rights Reserved  	*/
29 
30 /*
31  * University Copyright- Copyright (c) 1982, 1986, 1988
32  * The Regents of the University of California
33  * All Rights Reserved
34  *
35  * University Acknowledgment- Portions of this document are derived from
36  * software developed by the University of California, Berkeley, and its
37  * contributors.
38  */
39 
40 #pragma ident	"%Z%%M%	%I%	%E% SMI"
41 
42 #include "lint.h"
43 #include <string.h>
44 #include <limits.h>
45 #include <sys/types.h>
46 #include <sys/time.h>
47 #include <sys/resource.h>
48 #include <sys/procset.h>
49 #include <sys/priocntl.h>
50 #include <limits.h>
51 #include <errno.h>
52 #include <priv.h>
53 
54 static idtype_t
55 prio_to_idtype(int which)
56 {
57 	switch (which) {
58 
59 	case PRIO_PROCESS:
60 		return (P_PID);
61 
62 	case PRIO_PGRP:
63 		return (P_PGID);
64 
65 	case PRIO_USER:
66 		return (P_UID);
67 
68 	case PRIO_GROUP:
69 		return (P_GID);
70 
71 	case PRIO_SESSION:
72 		return (P_SID);
73 
74 	case PRIO_LWP:
75 		return (P_LWPID);
76 
77 	case PRIO_TASK:
78 		return (P_TASKID);
79 
80 	case PRIO_PROJECT:
81 		return (P_PROJID);
82 
83 	case PRIO_ZONE:
84 		return (P_ZONEID);
85 
86 	case PRIO_CONTRACT:
87 		return (P_CTID);
88 
89 	default:
90 		return (-1);
91 	}
92 }
93 
94 static int
95 old_idtype(int which)
96 {
97 	switch (which) {
98 	case PRIO_PROCESS:
99 	case PRIO_PGRP:
100 	case PRIO_USER:
101 		return (1);
102 	default:
103 		return (0);
104 	}
105 }
106 
107 int
108 getpriority(int which, id_t who)
109 {
110 	id_t id;
111 	idtype_t idtype;
112 	pcnice_t pcnice;
113 
114 	if ((idtype = prio_to_idtype(which)) == -1) {
115 		errno = EINVAL;
116 		return (-1);
117 	}
118 
119 	if (who < 0) {
120 		if (old_idtype(which)) {
121 			errno = EINVAL;
122 			return (-1);
123 		} else if (who != P_MYID) {
124 			errno = EINVAL;
125 			return (-1);
126 		}
127 	}
128 
129 	/*
130 	 * The POSIX standard requires that a 0 value for the who argument
131 	 * should specify the current process, process group, or user.
132 	 * For all other id types we can treat zero as normal id value.
133 	 */
134 	if (who == 0 && old_idtype(which))
135 		id = P_MYID;
136 	else
137 		id = who;
138 
139 	pcnice.pc_val = 0;
140 	pcnice.pc_op = PC_GETNICE;
141 
142 	if (priocntl(idtype, id, PC_DONICE, &pcnice) == -1)
143 		return (-1);
144 	else
145 		return (pcnice.pc_val);
146 }
147 
148 int
149 setpriority(int which, id_t who, int prio)
150 {
151 	id_t id;
152 	idtype_t idtype;
153 	pcnice_t pcnice;
154 	int ret;
155 
156 	if ((idtype = prio_to_idtype(which)) == -1) {
157 		errno = EINVAL;
158 		return (-1);
159 	}
160 
161 	if (who < 0) {
162 		if (old_idtype(which)) {
163 			errno = EINVAL;
164 			return (-1);
165 		} else if (who != P_MYID) {
166 			errno = EINVAL;
167 			return (-1);
168 		}
169 	}
170 
171 	if (who == 0 && old_idtype(which))
172 		id = P_MYID;
173 	else
174 		id = who;
175 
176 	if (prio > NZERO - 1)
177 		prio = NZERO - 1;
178 	else if (prio < -NZERO)
179 		prio = -NZERO;
180 
181 	pcnice.pc_val = prio;
182 	pcnice.pc_op = PC_SETNICE;
183 
184 	ret = priocntl(idtype, id, PC_DONICE, &pcnice);
185 
186 	if (ret != 0 && errno == EPERM) {
187 		pcnice_t	gpcnice = { 0, PC_GETNICE };
188 		priv_set_t	*pset = NULL;
189 
190 		/*
191 		 * The priocntl PC_DONICE subcommand returns EPERM if we lack
192 		 * sufficient privileges to carry out the operation, but
193 		 * setpriority(3C) may need to return EACCES.  We can't just
194 		 * change EPERM to EACCES, because there are other conditions
195 		 * which legitimately cause EPERM (such as an euid/ruid mismatch
196 		 * between the current process and the target.).
197 		 *
198 		 * setpriority(3C) must return EACCES if we lack the privilege
199 		 * checked for below and we are trying to increase the process
200 		 * priority (by lowering the numeric value of its priority).
201 		 */
202 		if (priocntl(idtype, id, PC_DONICE, &gpcnice) == 0 &&
203 		    prio < gpcnice.pc_val) {
204 			if ((pset = priv_allocset()) != NULL &&
205 			    getppriv(PRIV_EFFECTIVE, pset) == 0 &&
206 			    !priv_ismember(pset, "proc_priocntl"))
207 				errno = EACCES;
208 			if (pset != NULL)
209 				priv_freeset(pset);
210 		}
211 	}
212 
213 	return (ret);
214 }
215