1 /* $OpenBSD: kern_subr.c,v 1.32 2008/06/12 16:15:49 marco 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 <sys/kernel.h> 47 #include <sys/resourcevar.h> 48 49 int 50 uiomove(void *cp, int n, struct uio *uio) 51 { 52 struct iovec *iov; 53 u_int cnt; 54 int error = 0; 55 struct proc *p; 56 57 p = uio->uio_procp; 58 59 #ifdef DIAGNOSTIC 60 if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE) 61 panic("uiomove: mode"); 62 if (uio->uio_segflg == UIO_USERSPACE && p != curproc) 63 panic("uiomove: proc"); 64 #endif 65 while (n > 0 && uio->uio_resid) { 66 iov = uio->uio_iov; 67 cnt = iov->iov_len; 68 if (cnt == 0) { 69 uio->uio_iov++; 70 uio->uio_iovcnt--; 71 continue; 72 } 73 if (cnt > n) 74 cnt = n; 75 switch (uio->uio_segflg) { 76 77 case UIO_USERSPACE: 78 if (curcpu()->ci_schedstate.spc_schedflags & 79 SPCF_SHOULDYIELD) 80 preempt(NULL); 81 if (uio->uio_rw == UIO_READ) 82 error = copyout(cp, iov->iov_base, cnt); 83 else 84 error = copyin(iov->iov_base, cp, cnt); 85 if (error) 86 return (error); 87 break; 88 89 case UIO_SYSSPACE: 90 if (uio->uio_rw == UIO_READ) 91 error = kcopy(cp, iov->iov_base, cnt); 92 else 93 error = kcopy(iov->iov_base, cp, cnt); 94 if (error) 95 return(error); 96 } 97 iov->iov_base = (caddr_t)iov->iov_base + cnt; 98 iov->iov_len -= cnt; 99 uio->uio_resid -= cnt; 100 uio->uio_offset += cnt; 101 cp = (caddr_t)cp + cnt; 102 n -= cnt; 103 } 104 return (error); 105 } 106 107 /* 108 * Give next character to user as result of read. 109 */ 110 int 111 ureadc(int c, struct uio *uio) 112 { 113 struct iovec *iov; 114 115 if (uio->uio_resid == 0) 116 #ifdef DIAGNOSTIC 117 panic("ureadc: zero resid"); 118 #else 119 return (EINVAL); 120 #endif 121 again: 122 if (uio->uio_iovcnt <= 0) 123 #ifdef DIAGNOSTIC 124 panic("ureadc: non-positive iovcnt"); 125 #else 126 return (EINVAL); 127 #endif 128 iov = uio->uio_iov; 129 if (iov->iov_len <= 0) { 130 uio->uio_iovcnt--; 131 uio->uio_iov++; 132 goto again; 133 } 134 switch (uio->uio_segflg) { 135 136 case UIO_USERSPACE: 137 { 138 char tmp = c; 139 140 if (copyout(&tmp, iov->iov_base, sizeof(char)) != 0) 141 return (EFAULT); 142 } 143 break; 144 145 case UIO_SYSSPACE: 146 *(char *)iov->iov_base = c; 147 break; 148 } 149 iov->iov_base = (caddr_t)iov->iov_base + 1; 150 iov->iov_len--; 151 uio->uio_resid--; 152 uio->uio_offset++; 153 return (0); 154 } 155 156 /* 157 * General routine to allocate a hash table. 158 */ 159 void * 160 hashinit(int elements, int type, int flags, u_long *hashmask) 161 { 162 u_long hashsize, i; 163 LIST_HEAD(generic, generic) *hashtbl; 164 165 if (elements <= 0) 166 panic("hashinit: bad cnt"); 167 for (hashsize = 1; hashsize < elements; hashsize <<= 1) 168 continue; 169 hashtbl = malloc(hashsize * sizeof(*hashtbl), type, flags); 170 if (hashtbl == NULL) 171 return NULL; 172 for (i = 0; i < hashsize; i++) 173 LIST_INIT(&hashtbl[i]); 174 *hashmask = hashsize - 1; 175 return (hashtbl); 176 } 177 178 /* 179 * "Shutdown/startup hook" types, functions, and variables. 180 */ 181 182 struct hook_desc_head startuphook_list = 183 TAILQ_HEAD_INITIALIZER(startuphook_list); 184 struct hook_desc_head shutdownhook_list = 185 TAILQ_HEAD_INITIALIZER(shutdownhook_list); 186 struct hook_desc_head mountroothook_list = 187 TAILQ_HEAD_INITIALIZER(mountroothook_list); 188 189 void * 190 hook_establish(struct hook_desc_head *head, int tail, void (*fn)(void *), 191 void *arg) 192 { 193 struct hook_desc *hdp; 194 195 hdp = (struct hook_desc *)malloc(sizeof (*hdp), M_DEVBUF, M_NOWAIT); 196 if (hdp == NULL) 197 return (NULL); 198 199 hdp->hd_fn = fn; 200 hdp->hd_arg = arg; 201 if (tail) 202 TAILQ_INSERT_TAIL(head, hdp, hd_list); 203 else 204 TAILQ_INSERT_HEAD(head, hdp, hd_list); 205 206 return (hdp); 207 } 208 209 void 210 hook_disestablish(struct hook_desc_head *head, void *vhook) 211 { 212 struct hook_desc *hdp; 213 214 #ifdef DIAGNOSTIC 215 for (hdp = TAILQ_FIRST(head); hdp != NULL; 216 hdp = TAILQ_NEXT(hdp, hd_list)) 217 if (hdp == vhook) 218 break; 219 if (hdp == NULL) 220 return; 221 #endif 222 hdp = vhook; 223 TAILQ_REMOVE(head, hdp, hd_list); 224 free(hdp, M_DEVBUF); 225 } 226 227 /* 228 * Run hooks. Startup hooks are invoked right after scheduler_start but 229 * before root is mounted. Shutdown hooks are invoked immediately before the 230 * system is halted or rebooted, i.e. after file systems unmounted, 231 * after crash dump done, etc. 232 */ 233 void 234 dohooks(struct hook_desc_head *head, int flags) 235 { 236 struct hook_desc *hdp; 237 238 if ((flags & HOOK_REMOVE) == 0) { 239 TAILQ_FOREACH(hdp, head, hd_list) { 240 (*hdp->hd_fn)(hdp->hd_arg); 241 } 242 } else { 243 while ((hdp = TAILQ_FIRST(head)) != NULL) { 244 TAILQ_REMOVE(head, hdp, hd_list); 245 (*hdp->hd_fn)(hdp->hd_arg); 246 if ((flags & HOOK_FREE) != 0) 247 free(hdp, M_DEVBUF); 248 } 249 } 250 } 251 252 /* 253 * "Power hook" types, functions, and variables. 254 */ 255 256 struct powerhook_desc { 257 CIRCLEQ_ENTRY(powerhook_desc) sfd_list; 258 void (*sfd_fn)(int, void *); 259 void *sfd_arg; 260 }; 261 262 CIRCLEQ_HEAD(, powerhook_desc) powerhook_list = 263 CIRCLEQ_HEAD_INITIALIZER(powerhook_list); 264 265 void * 266 powerhook_establish(void (*fn)(int, void *), void *arg) 267 { 268 struct powerhook_desc *ndp; 269 270 ndp = (struct powerhook_desc *) 271 malloc(sizeof(*ndp), M_DEVBUF, M_NOWAIT); 272 if (ndp == NULL) 273 return NULL; 274 275 ndp->sfd_fn = fn; 276 ndp->sfd_arg = arg; 277 CIRCLEQ_INSERT_HEAD(&powerhook_list, ndp, sfd_list); 278 279 return (ndp); 280 } 281 282 void 283 powerhook_disestablish(void *vhook) 284 { 285 #ifdef DIAGNOSTIC 286 struct powerhook_desc *dp; 287 288 CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) 289 if (dp == vhook) 290 break; 291 if (dp == NULL) 292 panic("powerhook_disestablish: hook not established"); 293 #endif 294 295 CIRCLEQ_REMOVE(&powerhook_list, (struct powerhook_desc *)vhook, 296 sfd_list); 297 free(vhook, M_DEVBUF); 298 } 299 300 /* 301 * Run power hooks. 302 */ 303 void 304 dopowerhooks(int why) 305 { 306 struct powerhook_desc *dp; 307 int s; 308 309 s = splhigh(); 310 if (why == PWR_RESUME) { 311 CIRCLEQ_FOREACH_REVERSE(dp, &powerhook_list, sfd_list) { 312 (*dp->sfd_fn)(why, dp->sfd_arg); 313 } 314 } else { 315 CIRCLEQ_FOREACH(dp, &powerhook_list, sfd_list) { 316 (*dp->sfd_fn)(why, dp->sfd_arg); 317 } 318 } 319 splx(s); 320 } 321