1/* $NetBSD: kern_uidinfo.c,v 1.8 2013/03/10 17:55:42 pooka Exp $ */
2
3/*-
4 * Copyright (c) 1982, 1986, 1991, 1993
5 * The Regents of the University of California. All rights reserved.
6 * (c) UNIX System Laboratories, Inc.
7 * All or some portions of this file are derived from material licensed
8 * to the University of California by American Telephone and Telegraph
9 * Co. or Unix System Laboratories, Inc. and are reproduced herein with
10 * the permission of UNIX System Laboratories, Inc.
11 *
12 * Redistribution and use in source and binary forms, with or without
13 * modification, are permitted provided that the following conditions
14 * are met:
15 * 1. Redistributions of source code must retain the above copyright
16 * notice, this list of conditions and the following disclaimer.
17 * 2. Redistributions in binary form must reproduce the above copyright
18 * notice, this list of conditions and the following disclaimer in the
19 * documentation and/or other materials provided with the distribution.
20 * 3. Neither the name of the University nor the names of its contributors
21 * may be used to endorse or promote products derived from this software
22 * without specific prior written permission.
23 *
24 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34 * SUCH DAMAGE.
35 */
36
37#include <sys/cdefs.h>
38__KERNEL_RCSID(0, "$NetBSD: kern_uidinfo.c,v 1.8 2013/03/10 17:55:42 pooka Exp $");
39
40#include <sys/param.h>
41#include <sys/systm.h>
42#include <sys/kmem.h>
43#include <sys/proc.h>
44#include <sys/atomic.h>
45#include <sys/uidinfo.h>
46#include <sys/sysctl.h>
47#include <sys/kauth.h>
48#include <sys/cpu.h>
49
50static SLIST_HEAD(uihashhead, uidinfo) *uihashtbl;
51static u_long uihash;
52
53#define UIHASH(uid) (&uihashtbl[(uid) & uihash])
54
55static int
56sysctl_kern_uidinfo_cnt(SYSCTLFN_ARGS)
57{
58 static const struct {
59 const char *name;
60 u_int value;
61 } nv[] = {
62#define _MEM(n) { # n, offsetof(struct uidinfo, ui_ ## n) }
63 _MEM(proccnt),
64 _MEM(lwpcnt),
65 _MEM(lockcnt),
66 _MEM(sbsize),
67#undef _MEM
68 };
69
70 for (size_t i = 0; i < __arraycount(nv); i++)
71 if (strcmp(nv[i].name, rnode->sysctl_name) == 0) {
72 uint64_t cnt;
73 struct sysctlnode node = *rnode;
74 struct uidinfo *uip;
75
76 node.sysctl_data = &cnt;
77 uip = uid_find(kauth_cred_geteuid(l->l_cred));
78
79 *(uint64_t *)node.sysctl_data =
80 *(u_long *)((char *)uip + nv[i].value);
81
82 return sysctl_lookup(SYSCTLFN_CALL(&node));
83 }
84
85 return EINVAL;
86}
87
88static struct sysctllog *kern_uidinfo_sysctllog;
89
90static void
91sysctl_kern_uidinfo_setup(void)
92{
93 const struct sysctlnode *rnode, *cnode;
94
95 sysctl_createv(&kern_uidinfo_sysctllog, 0, NULL, &rnode,
96 CTLFLAG_PERMANENT,
97 CTLTYPE_NODE, "uidinfo",
98 SYSCTL_DESCR("Resource usage per uid"),
99 NULL, 0, NULL, 0,
100 CTL_KERN, CTL_CREATE, CTL_EOL);
101
102 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode,
103 CTLFLAG_PERMANENT,
104 CTLTYPE_QUAD, "proccnt",
105 SYSCTL_DESCR("Number of processes for the current user"),
106 sysctl_kern_uidinfo_cnt, 0, NULL, 0,
107 CTL_CREATE, CTL_EOL);
108 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode,
109 CTLFLAG_PERMANENT,
110 CTLTYPE_QUAD, "lwpcnt",
111 SYSCTL_DESCR("Number of lwps for the current user"),
112 sysctl_kern_uidinfo_cnt, 0, NULL, 0,
113 CTL_CREATE, CTL_EOL);
114 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode,
115 CTLFLAG_PERMANENT,
116 CTLTYPE_QUAD, "lockcnt",
117 SYSCTL_DESCR("Number of locks for the current user"),
118 sysctl_kern_uidinfo_cnt, 0, NULL, 0,
119 CTL_CREATE, CTL_EOL);
120 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode,
121 CTLFLAG_PERMANENT,
122 CTLTYPE_QUAD, "sbsize",
123 SYSCTL_DESCR("Socket buffers used for the current user"),
124 sysctl_kern_uidinfo_cnt, 0, NULL, 0,
125 CTL_CREATE, CTL_EOL);
126}
127
128void
129uid_init(void)
130{
131
132 /*
133 * In case of MP system, SLIST_FOREACH would force a cache line
134 * write-back for every modified 'uidinfo', thus we try to keep the
135 * lists short.
136 */
137 const u_int uihash_sz = (maxcpus > 1 ? 1024 : 64);
138
139 uihashtbl = hashinit(uihash_sz, HASH_SLIST, true, &uihash);
140
141 /*
142 * Ensure that uid 0 is always in the user hash table, as
143 * sbreserve() expects it available from interrupt context.
144 */
145 (void)uid_find(0);
146 sysctl_kern_uidinfo_setup();
147}
148
149struct uidinfo *
150uid_find(uid_t uid)
151{
152 struct uidinfo *uip, *uip_first, *newuip;
153 struct uihashhead *uipp;
154
155 uipp = UIHASH(uid);
156 newuip = NULL;
157
158 /*
159 * To make insertion atomic, abstraction of SLIST will be violated.
160 */
161 uip_first = uipp->slh_first;
162 again:
163 SLIST_FOREACH(uip, uipp, ui_hash) {
164 if (uip->ui_uid != uid)
165 continue;
166 if (newuip != NULL)
167 kmem_free(newuip, sizeof(*newuip));
168 return uip;
169 }
170 if (newuip == NULL)
171 newuip = kmem_zalloc(sizeof(*newuip), KM_SLEEP);
172 newuip->ui_uid = uid;
173
174 /*
175 * If atomic insert is unsuccessful, another thread might be
176 * allocated this 'uid', thus full re-check is needed.
177 */
178 newuip->ui_hash.sle_next = uip_first;
179 membar_producer();
180 uip = atomic_cas_ptr(&uipp->slh_first, uip_first, newuip);
181 if (uip != uip_first) {
182 uip_first = uip;
183 goto again;
184 }
185
186 return newuip;
187}
188
189/*
190 * Change the count associated with number of processes
191 * a given user is using.
192 */
193int
194chgproccnt(uid_t uid, int diff)
195{
196 struct uidinfo *uip;
197 long proccnt;
198
199 uip = uid_find(uid);
200 proccnt = atomic_add_long_nv(&uip->ui_proccnt, diff);
201 KASSERT(proccnt >= 0);
202 return proccnt;
203}
204
205/*
206 * Change the count associated with number of lwps
207 * a given user is using.
208 */
209int
210chglwpcnt(uid_t uid, int diff)
211{
212 struct uidinfo *uip;
213 long lwpcnt;
214
215 uip = uid_find(uid);
216 lwpcnt = atomic_add_long_nv(&uip->ui_lwpcnt, diff);
217 KASSERT(lwpcnt >= 0);
218 return lwpcnt;
219}
220
221int
222chgsbsize(struct uidinfo *uip, u_long *hiwat, u_long to, rlim_t xmax)
223{
224 rlim_t nsb;
225 const long diff = to - *hiwat;
226
227 nsb = (rlim_t)atomic_add_long_nv((long *)&uip->ui_sbsize, diff);
228 if (diff > 0 && nsb > xmax) {
229 atomic_add_long((long *)&uip->ui_sbsize, -diff);
230 return 0;
231 }
232 *hiwat = to;
233 return 1;
234}
235