1 /* $NetBSD: kern_uidinfo.c,v 1.15 2026/01/04 02:09:21 riastradh 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 1.15 2026/01/04 02:09:21 riastradh Exp $"); 39 40 #include <sys/param.h> 41 #include <sys/types.h> 42 43 #include <sys/atomic.h> 44 #include <sys/cpu.h> 45 #include <sys/kauth.h> 46 #include <sys/kmem.h> 47 #include <sys/proc.h> 48 #include <sys/sdt.h> 49 #include <sys/sysctl.h> 50 #include <sys/systm.h> 51 #include <sys/uidinfo.h> 52 53 static SLIST_HEAD(uihashhead, uidinfo) *uihashtbl; 54 static u_long uihash; 55 56 #define UIHASH(uid) (&uihashtbl[(uid) & uihash]) 57 58 static int 59 sysctl_kern_uidinfo_cnt(SYSCTLFN_ARGS) 60 { 61 static const struct { 62 const char *name; 63 u_int value; 64 } nv[] = { 65 #define _MEM(n) { # n, offsetof(struct uidinfo, ui_ ## n) } 66 _MEM(proccnt), 67 _MEM(lwpcnt), 68 _MEM(lockcnt), 69 _MEM(semcnt), 70 _MEM(sbsize), 71 #undef _MEM 72 }; 73 74 for (size_t i = 0; i < __arraycount(nv); i++) 75 if (strcmp(nv[i].name, rnode->sysctl_name) == 0) { 76 uint64_t cnt; 77 struct sysctlnode node = *rnode; 78 struct uidinfo *uip; 79 80 node.sysctl_data = &cnt; 81 uip = uid_find(kauth_cred_geteuid(l->l_cred)); 82 83 *(uint64_t *)node.sysctl_data = 84 *(u_long *)((char *)uip + nv[i].value); 85 86 return sysctl_lookup(SYSCTLFN_CALL(&node)); 87 } 88 89 return SET_ERROR(EINVAL); 90 } 91 92 static struct sysctllog *kern_uidinfo_sysctllog; 93 94 static void 95 sysctl_kern_uidinfo_setup(void) 96 { 97 const struct sysctlnode *rnode, *cnode; 98 99 sysctl_createv(&kern_uidinfo_sysctllog, 0, NULL, &rnode, 100 CTLFLAG_PERMANENT, 101 CTLTYPE_NODE, "uidinfo", 102 SYSCTL_DESCR("Resource usage per uid"), 103 NULL, 0, NULL, 0, 104 CTL_KERN, CTL_CREATE, CTL_EOL); 105 106 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode, 107 CTLFLAG_PERMANENT, 108 CTLTYPE_QUAD, "proccnt", 109 SYSCTL_DESCR("Number of processes for the current user"), 110 sysctl_kern_uidinfo_cnt, 0, NULL, 0, 111 CTL_CREATE, CTL_EOL); 112 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode, 113 CTLFLAG_PERMANENT, 114 CTLTYPE_QUAD, "lwpcnt", 115 SYSCTL_DESCR("Number of lwps for the current user"), 116 sysctl_kern_uidinfo_cnt, 0, NULL, 0, 117 CTL_CREATE, CTL_EOL); 118 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode, 119 CTLFLAG_PERMANENT, 120 CTLTYPE_QUAD, "lockcnt", 121 SYSCTL_DESCR("Number of locks for the current user"), 122 sysctl_kern_uidinfo_cnt, 0, NULL, 0, 123 CTL_CREATE, CTL_EOL); 124 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode, 125 CTLFLAG_PERMANENT, 126 CTLTYPE_QUAD, "semcnt", 127 SYSCTL_DESCR("Number of semaphores used for the current user"), 128 sysctl_kern_uidinfo_cnt, 0, NULL, 0, 129 CTL_CREATE, CTL_EOL); 130 sysctl_createv(&kern_uidinfo_sysctllog, 0, &rnode, &cnode, 131 CTLFLAG_PERMANENT, 132 CTLTYPE_QUAD, "sbsize", 133 SYSCTL_DESCR("Socket buffers used for the current user"), 134 sysctl_kern_uidinfo_cnt, 0, NULL, 0, 135 CTL_CREATE, CTL_EOL); 136 } 137 138 static int 139 uid_stats(struct hashstat_sysctl *hs, bool fill) 140 { 141 struct uidinfo *uip; 142 uint64_t chain; 143 144 strlcpy(hs->hash_name, "uihash", sizeof(hs->hash_name)); 145 strlcpy(hs->hash_desc, "user info (uid->used proc) hash", 146 sizeof(hs->hash_desc)); 147 if (!fill) 148 return 0; 149 150 hs->hash_size = uihash + 1; 151 152 for (size_t i = 0; i < hs->hash_size; i++) { 153 chain = 0; 154 SLIST_FOREACH(uip, &uihashtbl[i], ui_hash) { 155 membar_datadep_consumer(); 156 chain++; 157 } 158 if (chain > 0) { 159 hs->hash_used++; 160 hs->hash_items += chain; 161 if (chain > hs->hash_maxchain) 162 hs->hash_maxchain = chain; 163 } 164 } 165 166 return 0; 167 } 168 169 void 170 uid_init(void) 171 { 172 173 /* 174 * In case of MP system, SLIST_FOREACH would force a cache line 175 * write-back for every modified 'uidinfo', thus we try to keep the 176 * lists short. 177 */ 178 const u_int uihash_sz = (maxcpus > 1 ? 1024 : 64); 179 180 uihashtbl = hashinit(uihash_sz, HASH_SLIST, true, &uihash); 181 182 /* 183 * Ensure that uid 0 is always in the user hash table, as 184 * sbreserve() expects it available from interrupt context. 185 */ 186 (void)uid_find(0); 187 sysctl_kern_uidinfo_setup(); 188 hashstat_register("uihash", uid_stats); 189 } 190 191 struct uidinfo * 192 uid_find(uid_t uid) 193 { 194 struct uidinfo *uip, *uip_first, *newuip; 195 struct uihashhead *uipp; 196 197 uipp = UIHASH(uid); 198 newuip = NULL; 199 200 /* 201 * To make insertion atomic, abstraction of SLIST will be violated. 202 */ 203 uip_first = uipp->slh_first; 204 again: 205 SLIST_FOREACH(uip, uipp, ui_hash) { 206 membar_datadep_consumer(); 207 if (uip->ui_uid != uid) 208 continue; 209 if (newuip != NULL) 210 kmem_free(newuip, sizeof(*newuip)); 211 return uip; 212 } 213 if (newuip == NULL) 214 newuip = kmem_zalloc(sizeof(*newuip), KM_SLEEP); 215 newuip->ui_uid = uid; 216 217 /* 218 * If atomic insert is unsuccessful, another thread might be 219 * allocated this 'uid', thus full re-check is needed. 220 */ 221 newuip->ui_hash.sle_next = uip_first; 222 membar_producer(); 223 uip = atomic_cas_ptr(&uipp->slh_first, uip_first, newuip); 224 if (uip != uip_first) { 225 uip_first = uip; 226 goto again; 227 } 228 229 return newuip; 230 } 231 232 /* 233 * Change the count associated with number of processes 234 * a given user is using. 235 */ 236 int 237 chgproccnt(uid_t uid, int diff) 238 { 239 struct uidinfo *uip; 240 long proccnt; 241 242 uip = uid_find(uid); 243 proccnt = atomic_add_long_nv(&uip->ui_proccnt, diff); 244 KASSERTMSG(proccnt >= 0, "uid=%d diff=%d proccnt=%ld", 245 uid, diff, proccnt); 246 return proccnt; 247 } 248 249 /* 250 * Change the count associated with number of lwps 251 * a given user is using. 252 */ 253 int 254 chglwpcnt(uid_t uid, int diff) 255 { 256 struct uidinfo *uip; 257 long lwpcnt; 258 259 uip = uid_find(uid); 260 lwpcnt = atomic_add_long_nv(&uip->ui_lwpcnt, diff); 261 KASSERTMSG(lwpcnt >= 0, "uid=%d diff=%d lwpcnt=%ld", 262 uid, diff, lwpcnt); 263 return lwpcnt; 264 } 265 266 /* 267 * Change the count associated with number of semaphores 268 * a given user is using. 269 */ 270 int 271 chgsemcnt(uid_t uid, int diff) 272 { 273 struct uidinfo *uip; 274 long semcnt; 275 276 uip = uid_find(uid); 277 semcnt = atomic_add_long_nv(&uip->ui_semcnt, diff); 278 KASSERTMSG(semcnt >= 0, "uid=%d diff=%d semcnt=%ld", 279 uid, diff, semcnt); 280 return semcnt; 281 } 282 283 int 284 chgsbsize(struct uidinfo *uip, u_long *hiwat, u_long to, rlim_t xmax) 285 { 286 rlim_t nsb; 287 const long diff = to - *hiwat; 288 289 nsb = (rlim_t)atomic_add_long_nv((long *)&uip->ui_sbsize, diff); 290 if (diff > 0 && nsb > xmax) { 291 atomic_add_long((long *)&uip->ui_sbsize, -diff); 292 return 0; 293 } 294 *hiwat = to; 295 return 1; 296 } 297
Indexes created Sat Feb 21 16:20:20 UTC 2026