1 /* $OpenBSD: kern_subr.c,v 1.35 2013/08/13 05:52:23 guenther 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 ((int)uio->uio_segflg) { 76 77 case UIO_USERSPACE | 0x10: 78 case UIO_USERSPACE: 79 if (curcpu()->ci_schedstate.spc_schedflags & 80 SPCF_SHOULDYIELD) 81 preempt(NULL); 82 if (uio->uio_rw == UIO_READ) 83 error = copyout(cp, iov->iov_base, cnt); 84 else 85 error = copyin(iov->iov_base, cp, cnt); 86 if (error) 87 return (error); 88 break; 89 90 case UIO_SYSSPACE: 91 if (uio->uio_rw == UIO_READ) 92 error = kcopy(cp, iov->iov_base, cnt); 93 else 94 error = kcopy(iov->iov_base, cp, cnt); 95 if (error) 96 return(error); 97 } 98 iov->iov_base = (caddr_t)iov->iov_base + cnt; 99 iov->iov_len -= cnt; 100 uio->uio_resid -= cnt; 101 uio->uio_offset += cnt; 102 cp = (caddr_t)cp + cnt; 103 n -= cnt; 104 } 105 return (error); 106 } 107 108 /* 109 * Give next character to user as result of read. 110 */ 111 int 112 ureadc(int c, struct uio *uio) 113 { 114 struct iovec *iov; 115 116 if (uio->uio_resid == 0) 117 #ifdef DIAGNOSTIC 118 panic("ureadc: zero resid"); 119 #else 120 return (EINVAL); 121 #endif 122 again: 123 if (uio->uio_iovcnt <= 0) 124 #ifdef DIAGNOSTIC 125 panic("ureadc: non-positive iovcnt"); 126 #else 127 return (EINVAL); 128 #endif 129 iov = uio->uio_iov; 130 if (iov->iov_len <= 0) { 131 uio->uio_iovcnt--; 132 uio->uio_iov++; 133 goto again; 134 } 135 switch ((int)uio->uio_segflg) { 136 137 case UIO_USERSPACE | 0x10: 138 case UIO_USERSPACE: 139 { 140 char tmp = c; 141 142 if (copyout(&tmp, iov->iov_base, sizeof(char)) != 0) 143 return (EFAULT); 144 } 145 break; 146 147 case UIO_SYSSPACE: 148 *(char *)iov->iov_base = c; 149 break; 150 } 151 iov->iov_base = (caddr_t)iov->iov_base + 1; 152 iov->iov_len--; 153 uio->uio_resid--; 154 uio->uio_offset++; 155 return (0); 156 } 157 158 /* 159 * General routine to allocate a hash table. 160 */ 161 void * 162 hashinit(int elements, int type, int flags, u_long *hashmask) 163 { 164 u_long hashsize, i; 165 LIST_HEAD(generic, generic) *hashtbl; 166 167 if (elements <= 0) 168 panic("hashinit: bad cnt"); 169 for (hashsize = 1; hashsize < elements; hashsize <<= 1) 170 continue; 171 hashtbl = malloc(hashsize * sizeof(*hashtbl), type, flags); 172 if (hashtbl == NULL) 173 return NULL; 174 for (i = 0; i < hashsize; i++) 175 LIST_INIT(&hashtbl[i]); 176 *hashmask = hashsize - 1; 177 return (hashtbl); 178 } 179 180 /* 181 * "Shutdown/startup hook" types, functions, and variables. 182 */ 183 184 struct hook_desc_head startuphook_list = 185 TAILQ_HEAD_INITIALIZER(startuphook_list); 186 struct hook_desc_head shutdownhook_list = 187 TAILQ_HEAD_INITIALIZER(shutdownhook_list); 188 struct hook_desc_head mountroothook_list = 189 TAILQ_HEAD_INITIALIZER(mountroothook_list); 190 191 void * 192 hook_establish(struct hook_desc_head *head, int tail, void (*fn)(void *), 193 void *arg) 194 { 195 struct hook_desc *hdp; 196 197 hdp = (struct hook_desc *)malloc(sizeof (*hdp), M_DEVBUF, M_NOWAIT); 198 if (hdp == NULL) 199 return (NULL); 200 201 hdp->hd_fn = fn; 202 hdp->hd_arg = arg; 203 if (tail) 204 TAILQ_INSERT_TAIL(head, hdp, hd_list); 205 else 206 TAILQ_INSERT_HEAD(head, hdp, hd_list); 207 208 return (hdp); 209 } 210 211 void 212 hook_disestablish(struct hook_desc_head *head, void *vhook) 213 { 214 struct hook_desc *hdp; 215 216 #ifdef DIAGNOSTIC 217 for (hdp = TAILQ_FIRST(head); hdp != NULL; 218 hdp = TAILQ_NEXT(hdp, hd_list)) 219 if (hdp == vhook) 220 break; 221 if (hdp == NULL) 222 return; 223 #endif 224 hdp = vhook; 225 TAILQ_REMOVE(head, hdp, hd_list); 226 free(hdp, M_DEVBUF); 227 } 228 229 /* 230 * Run hooks. Startup hooks are invoked right after scheduler_start but 231 * before root is mounted. Shutdown hooks are invoked immediately before the 232 * system is halted or rebooted, i.e. after file systems unmounted, 233 * after crash dump done, etc. 234 */ 235 void 236 dohooks(struct hook_desc_head *head, int flags) 237 { 238 struct hook_desc *hdp; 239 240 if ((flags & HOOK_REMOVE) == 0) { 241 TAILQ_FOREACH(hdp, head, hd_list) { 242 (*hdp->hd_fn)(hdp->hd_arg); 243 } 244 } else { 245 while ((hdp = TAILQ_FIRST(head)) != NULL) { 246 TAILQ_REMOVE(head, hdp, hd_list); 247 (*hdp->hd_fn)(hdp->hd_arg); 248 if ((flags & HOOK_FREE) != 0) 249 free(hdp, M_DEVBUF); 250 } 251 } 252 } 253