1 /* $OpenBSD: kern_subr.c,v 1.19 2001/06/27 04:49:45 art 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. All advertising materials mentioning features or use of this software 22 * must display the following acknowledgement: 23 * This product includes software developed by the University of 24 * California, Berkeley and its contributors. 25 * 4. Neither the name of the University nor the names of its contributors 26 * may be used to endorse or promote products derived from this software 27 * without specific prior written permission. 28 * 29 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 30 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 31 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 32 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 33 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 34 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 35 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 36 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 37 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 38 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 39 * SUCH DAMAGE. 40 * 41 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94 42 */ 43 44 #include <sys/param.h> 45 #include <sys/systm.h> 46 #include <sys/proc.h> 47 #include <sys/malloc.h> 48 #include <sys/queue.h> 49 #include <sys/kernel.h> 50 #include <sys/resourcevar.h> 51 52 int 53 uiomove(cp, n, uio) 54 register caddr_t cp; 55 register int n; 56 register struct uio *uio; 57 { 58 register struct iovec *iov; 59 u_int cnt; 60 int error = 0; 61 struct proc *p; 62 63 p = uio->uio_procp; 64 65 #ifdef DIAGNOSTIC 66 if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE) 67 panic("uiomove: mode"); 68 if (uio->uio_segflg == UIO_USERSPACE && p != curproc) 69 panic("uiomove: proc"); 70 #endif 71 while (n > 0 && uio->uio_resid) { 72 iov = uio->uio_iov; 73 cnt = iov->iov_len; 74 if (cnt == 0) { 75 uio->uio_iov++; 76 uio->uio_iovcnt--; 77 continue; 78 } 79 if (cnt > n) 80 cnt = n; 81 switch (uio->uio_segflg) { 82 83 case UIO_USERSPACE: 84 if (p->p_schedflags & PSCHED_SHOULDYIELD) 85 preempt(NULL); 86 if (uio->uio_rw == UIO_READ) 87 error = copyout(cp, iov->iov_base, cnt); 88 else 89 error = copyin(iov->iov_base, cp, cnt); 90 if (error) 91 return (error); 92 break; 93 94 case UIO_SYSSPACE: 95 if (uio->uio_rw == UIO_READ) 96 error = kcopy(cp, iov->iov_base, cnt); 97 else 98 error = kcopy(iov->iov_base, cp, cnt); 99 if (error) 100 return(error); 101 } 102 iov->iov_base = (caddr_t)iov->iov_base + cnt; 103 iov->iov_len -= cnt; 104 uio->uio_resid -= cnt; 105 uio->uio_offset += cnt; 106 cp += cnt; 107 n -= cnt; 108 } 109 return (error); 110 } 111 112 /* 113 * Give next character to user as result of read. 114 */ 115 int 116 ureadc(c, uio) 117 register int c; 118 register struct uio *uio; 119 { 120 register struct iovec *iov; 121 122 if (uio->uio_resid == 0) 123 #ifdef DIAGNOSTIC 124 panic("ureadc: zero resid"); 125 #else 126 return (EINVAL); 127 #endif 128 again: 129 if (uio->uio_iovcnt <= 0) 130 #ifdef DIAGNOSTIC 131 panic("ureadc: non-positive iovcnt"); 132 #else 133 return (EINVAL); 134 #endif 135 iov = uio->uio_iov; 136 if (iov->iov_len <= 0) { 137 uio->uio_iovcnt--; 138 uio->uio_iov++; 139 goto again; 140 } 141 switch (uio->uio_segflg) { 142 143 case UIO_USERSPACE: 144 if (subyte(iov->iov_base, c) < 0) 145 return (EFAULT); 146 break; 147 148 case UIO_SYSSPACE: 149 *(char *)iov->iov_base = c; 150 break; 151 } 152 iov->iov_base = (caddr_t)iov->iov_base + 1; 153 iov->iov_len--; 154 uio->uio_resid--; 155 uio->uio_offset++; 156 return (0); 157 } 158 159 /* 160 * General routine to allocate a hash table. 161 */ 162 void * 163 hashinit(elements, type, flags, hashmask) 164 int elements, type, flags; 165 u_long *hashmask; 166 { 167 long hashsize; 168 LIST_HEAD(generic, generic) *hashtbl; 169 int i; 170 171 if (elements <= 0) 172 panic("hashinit: bad cnt"); 173 for (hashsize = 1; hashsize <= elements; hashsize <<= 1) 174 continue; 175 hashsize >>= 1; 176 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, flags); 177 if (hashtbl == NULL) 178 return NULL; 179 for (i = 0; i < hashsize; i++) 180 LIST_INIT(&hashtbl[i]); 181 *hashmask = hashsize - 1; 182 return (hashtbl); 183 } 184 185 /* 186 * "Shutdown hook" types, functions, and variables. 187 */ 188 189 struct shutdownhook_desc { 190 LIST_ENTRY(shutdownhook_desc) sfd_list; 191 void (*sfd_fn) __P((void *)); 192 void *sfd_arg; 193 }; 194 195 LIST_HEAD(, shutdownhook_desc) shutdownhook_list; 196 197 int shutdownhooks_done; 198 199 void * 200 shutdownhook_establish(fn, arg) 201 void (*fn) __P((void *)); 202 void *arg; 203 { 204 struct shutdownhook_desc *ndp; 205 206 ndp = (struct shutdownhook_desc *) 207 malloc(sizeof (*ndp), M_DEVBUF, M_NOWAIT); 208 if (ndp == NULL) 209 return NULL; 210 211 ndp->sfd_fn = fn; 212 ndp->sfd_arg = arg; 213 LIST_INSERT_HEAD(&shutdownhook_list, ndp, sfd_list); 214 215 return (ndp); 216 } 217 218 void 219 shutdownhook_disestablish(vhook) 220 void *vhook; 221 { 222 #ifdef DIAGNOSTIC 223 struct shutdownhook_desc *dp; 224 225 for (dp = shutdownhook_list.lh_first; dp != NULL; 226 dp = dp->sfd_list.le_next) 227 if (dp == vhook) 228 break; 229 if (dp == NULL) 230 panic("shutdownhook_disestablish: hook not established"); 231 #endif 232 233 LIST_REMOVE((struct shutdownhook_desc *)vhook, sfd_list); 234 } 235 236 /* 237 * Run shutdown hooks. Should be invoked immediately before the 238 * system is halted or rebooted, i.e. after file systems unmounted, 239 * after crash dump done, etc. 240 */ 241 void 242 doshutdownhooks() 243 { 244 struct shutdownhook_desc *dp; 245 246 if (shutdownhooks_done) 247 return; 248 249 for (dp = shutdownhook_list.lh_first; dp != NULL; dp = 250 dp->sfd_list.le_next) 251 (*dp->sfd_fn)(dp->sfd_arg); 252 } 253 254 /* 255 * "Power hook" types, functions, and variables. 256 */ 257 258 struct powerhook_desc { 259 CIRCLEQ_ENTRY(powerhook_desc) sfd_list; 260 void (*sfd_fn) __P((int, void *)); 261 void *sfd_arg; 262 }; 263 264 CIRCLEQ_HEAD(, powerhook_desc) powerhook_list = 265 CIRCLEQ_HEAD_INITIALIZER(powerhook_list); 266 267 void * 268 powerhook_establish(fn, arg) 269 void (*fn) __P((int, void *)); 270 void *arg; 271 { 272 struct powerhook_desc *ndp; 273 274 ndp = (struct powerhook_desc *) 275 malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT); 276 if (ndp == NULL) 277 return NULL; 278 279 ndp->sfd_fn = fn; 280 ndp->sfd_arg = arg; 281 CIRCLEQ_INSERT_HEAD(&powerhook_list, ndp, sfd_list); 282 283 return (ndp); 284 } 285 286 void 287 powerhook_disestablish(vhook) 288 void *vhook; 289 { 290 #ifdef DIAGNOSTIC 291 struct powerhook_desc *dp; 292 293 CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) 294 if (dp == vhook) 295 break; 296 if (dp == NULL) 297 panic("powerhook_disestablish: hook not established"); 298 #endif 299 300 CIRCLEQ_REMOVE(&powerhook_list, (struct powerhook_desc *)vhook, 301 sfd_list); 302 free(vhook, M_DEVBUF); 303 } 304 305 /* 306 * Run power hooks. 307 */ 308 void 309 dopowerhooks(why) 310 int why; 311 { 312 struct powerhook_desc *dp; 313 int s; 314 315 s = splhigh(); 316 if (why == PWR_RESUME) { 317 CIRCLEQ_FOREACH_REVERSE(dp, &powerhook_list, sfd_list) { 318 (*dp->sfd_fn)(why, dp->sfd_arg); 319 } 320 } else { 321 CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) { 322 (*dp->sfd_fn)(why, dp->sfd_arg); 323 } 324 } 325 splx(s); 326 } 327