1/* $OpenBSD: kern_subr.c,v 1.52 2023/01/31 15:18:56 deraadt Exp $ */ 2/* $NetBSD: kern_subr.c,v 1.15 1996/04/09 17:21:56 ragge Exp $ */ 3 4/* 5 * Copyright (c) 1982, 1986, 1991, 1993 6 * The Regents of the University of California. All rights reserved. 7 * (c) UNIX System Laboratories, Inc. 8 * All or some portions of this file are derived from material licensed 9 * to the University of California by American Telephone and Telegraph 10 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 11 * the permission of UNIX System Laboratories, Inc. 12 * 13 * Redistribution and use in source and binary forms, with or without 14 * modification, are permitted provided that the following conditions 15 * are met: 16 * 1. Redistributions of source code must retain the above copyright 17 * notice, this list of conditions and the following disclaimer. 18 * 2. Redistributions in binary form must reproduce the above copyright 19 * notice, this list of conditions and the following disclaimer in the 20 * documentation and/or other materials provided with the distribution. 21 * 3. Neither the name of the University nor the names of its contributors 22 * may be used to endorse or promote products derived from this software 23 * without specific prior written permission. 24 * 25 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 26 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 27 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 28 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 29 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 30 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 31 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 32 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 33 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 34 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 35 * SUCH DAMAGE. 36 * 37 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94 38 */ 39 40#include <sys/param.h> 41#include <sys/systm.h> 42#include <sys/proc.h> 43#include <sys/sched.h> 44#include <sys/malloc.h> 45#include <sys/queue.h> 46#include <uvm/uvm_extern.h> 47 48#ifdef PMAP_CHECK_COPYIN 49 50static inline int check_copyin(struct proc *, const void *, size_t); 51extern int _copyinstr(const void *, void *, size_t, size_t *); 52extern int _copyin(const void *uaddr, void *kaddr, size_t len); 53 54/* 55 * If range overlaps an check_copyin region, return EFAULT 56 */ 57static inline int 58check_copyin(struct proc *p, const void *vstart, size_t len) 59{ 60 struct vm_map *map = &p->p_vmspace->vm_map; 61 const vaddr_t start = (vaddr_t)vstart; 62 const vaddr_t end = start + len; 63 int i, max; 64 65 /* XXX if the array was sorted, we could shortcut */ 66 max = map->check_copyin_count; 67 membar_consumer(); 68 for (i = 0; i < max; i++) { 69 vaddr_t s = map->check_copyin[i].start; 70 vaddr_t e = map->check_copyin[i].end; 71 if ((start >= s && start < e) || (end > s && end < e)) 72 return EFAULT; 73 } 74 return (0); 75} 76 77int 78copyinstr(const void *uaddr, void *kaddr, size_t len, size_t *done) 79{ 80 size_t alen; 81 int error; 82 83 /* 84 * Must do the copyin checks after figuring out the string length, 85 * the buffer size length may cross into another ELF segment 86 */ 87 error = _copyinstr(uaddr, kaddr, len, &alen); 88 if (PMAP_CHECK_COPYIN && error == 0) 89 error = check_copyin(curproc, uaddr, alen); 90 if (done) 91 *done = alen; 92 return (error); 93} 94 95int 96copyin(const void *uaddr, void *kaddr, size_t len) 97{ 98 int error = 0; 99 100 if (PMAP_CHECK_COPYIN) 101 error = check_copyin(curproc, uaddr, len); 102 if (error == 0) 103 error = _copyin(uaddr, kaddr, len); 104 return (error); 105} 106#endif /* PMAP_CHECK_COPYIN */ 107 108int 109uiomove(void *cp, size_t n, struct uio *uio) 110{ 111 struct iovec *iov; 112 size_t cnt; 113 int error = 0; 114 115#ifdef DIAGNOSTIC 116 if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE) 117 panic("uiomove: mode"); 118 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 119 panic("uiomove: proc"); 120#endif 121 122 if (n > uio->uio_resid) 123 n = uio->uio_resid; 124 125 while (n > 0) { 126 iov = uio->uio_iov; 127 cnt = iov->iov_len; 128 if (cnt == 0) { 129 KASSERT(uio->uio_iovcnt > 0); 130 uio->uio_iov++; 131 uio->uio_iovcnt--; 132 continue; 133 } 134 if (cnt > n) 135 cnt = n; 136 switch (uio->uio_segflg) { 137 138 case UIO_USERSPACE: 139 sched_pause(preempt); 140 if (uio->uio_rw == UIO_READ) 141 error = copyout(cp, iov->iov_base, cnt); 142 else 143 error = copyin(iov->iov_base, cp, cnt); 144 if (error) 145 return (error); 146 break; 147 148 case UIO_SYSSPACE: 149 if (uio->uio_rw == UIO_READ) 150 error = kcopy(cp, iov->iov_base, cnt); 151 else 152 error = kcopy(iov->iov_base, cp, cnt); 153 if (error) 154 return(error); 155 } 156 iov->iov_base = (caddr_t)iov->iov_base + cnt; 157 iov->iov_len -= cnt; 158 uio->uio_resid -= cnt; 159 uio->uio_offset += cnt; 160 cp = (caddr_t)cp + cnt; 161 n -= cnt; 162 } 163 return (error); 164} 165 166/* 167 * Give next character to user as result of read. 168 */ 169int 170ureadc(int c, struct uio *uio) 171{ 172 struct iovec *iov; 173 174 if (uio->uio_resid == 0) 175#ifdef DIAGNOSTIC 176 panic("ureadc: zero resid"); 177#else 178 return (EINVAL); 179#endif 180again: 181 if (uio->uio_iovcnt <= 0) 182#ifdef DIAGNOSTIC 183 panic("ureadc: non-positive iovcnt"); 184#else 185 return (EINVAL); 186#endif 187 iov = uio->uio_iov; 188 if (iov->iov_len <= 0) { 189 uio->uio_iovcnt--; 190 uio->uio_iov++; 191 goto again; 192 } 193 switch (uio->uio_segflg) { 194 195 case UIO_USERSPACE: 196 { 197 char tmp = c; 198 199 if (copyout(&tmp, iov->iov_base, sizeof(char)) != 0) 200 return (EFAULT); 201 } 202 break; 203 204 case UIO_SYSSPACE: 205 *(char *)iov->iov_base = c; 206 break; 207 } 208 iov->iov_base = (caddr_t)iov->iov_base + 1; 209 iov->iov_len--; 210 uio->uio_resid--; 211 uio->uio_offset++; 212 return (0); 213} 214 215/* 216 * General routine to allocate a hash table. 217 */ 218void * 219hashinit(int elements, int type, int flags, u_long *hashmask) 220{ 221 u_long hashsize, i; 222 LIST_HEAD(generic, generic) *hashtbl; 223 224 if (elements <= 0) 225 panic("hashinit: bad cnt"); 226 if ((elements & (elements - 1)) == 0) 227 hashsize = elements; 228 else 229 for (hashsize = 1; hashsize < elements; hashsize <<= 1) 230 continue; 231 hashtbl = mallocarray(hashsize, sizeof(*hashtbl), type, flags); 232 if (hashtbl == NULL) 233 return NULL; 234 for (i = 0; i < hashsize; i++) 235 LIST_INIT(&hashtbl[i]); 236 *hashmask = hashsize - 1; 237 return (hashtbl); 238} 239 240void 241hashfree(void *hash, int elements, int type) 242{ 243 u_long hashsize; 244 LIST_HEAD(generic, generic) *hashtbl = hash; 245 246 if (elements <= 0) 247 panic("hashfree: bad cnt"); 248 if ((elements & (elements - 1)) == 0) 249 hashsize = elements; 250 else 251 for (hashsize = 1; hashsize < elements; hashsize <<= 1) 252 continue; 253 254 free(hashtbl, type, sizeof(*hashtbl) * hashsize); 255} 256 257/* 258 * "startup hook" types, functions, and variables. 259 */ 260 261struct hook_desc_head startuphook_list = 262 TAILQ_HEAD_INITIALIZER(startuphook_list); 263 264void * 265hook_establish(struct hook_desc_head *head, int tail, void (*fn)(void *), 266 void *arg) 267{ 268 struct hook_desc *hdp; 269 270 hdp = malloc(sizeof(*hdp), M_DEVBUF, M_NOWAIT); 271 if (hdp == NULL) 272 return (NULL); 273 274 hdp->hd_fn = fn; 275 hdp->hd_arg = arg; 276 if (tail) 277 TAILQ_INSERT_TAIL(head, hdp, hd_list); 278 else 279 TAILQ_INSERT_HEAD(head, hdp, hd_list); 280 281 return (hdp); 282} 283 284void 285hook_disestablish(struct hook_desc_head *head, void *vhook) 286{ 287 struct hook_desc *hdp; 288 289#ifdef DIAGNOSTIC 290 for (hdp = TAILQ_FIRST(head); hdp != NULL; 291 hdp = TAILQ_NEXT(hdp, hd_list)) 292 if (hdp == vhook) 293 break; 294 if (hdp == NULL) 295 return; 296#endif 297 hdp = vhook; 298 TAILQ_REMOVE(head, hdp, hd_list); 299 free(hdp, M_DEVBUF, sizeof(*hdp)); 300} 301 302/* 303 * Run hooks. Startup hooks are invoked right after scheduler_start but 304 * before root is mounted. Shutdown hooks are invoked immediately before the 305 * system is halted or rebooted, i.e. after file systems unmounted, 306 * after crash dump done, etc. 307 */ 308void 309dohooks(struct hook_desc_head *head, int flags) 310{ 311 struct hook_desc *hdp, *hdp_temp; 312 313 if ((flags & HOOK_REMOVE) == 0) { 314 TAILQ_FOREACH_SAFE(hdp, head, hd_list, hdp_temp) { 315 (*hdp->hd_fn)(hdp->hd_arg); 316 } 317 } else { 318 while ((hdp = TAILQ_FIRST(head)) != NULL) { 319 TAILQ_REMOVE(head, hdp, hd_list); 320 (*hdp->hd_fn)(hdp->hd_arg); 321 if ((flags & HOOK_FREE) != 0) 322 free(hdp, M_DEVBUF, sizeof(*hdp)); 323 } 324 } 325} 326