1 /* $OpenBSD: kern_subr.c,v 1.5 1998/05/11 05:41:59 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. 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 50 int 51 uiomove(cp, n, uio) 52 register caddr_t cp; 53 register int n; 54 register struct uio *uio; 55 { 56 register struct iovec *iov; 57 u_int cnt; 58 int error = 0; 59 60 #ifdef DIAGNOSTIC 61 if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE) 62 panic("uiomove: mode"); 63 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 64 panic("uiomove proc"); 65 #endif 66 while (n > 0 && uio->uio_resid) { 67 iov = uio->uio_iov; 68 cnt = iov->iov_len; 69 if (cnt == 0) { 70 uio->uio_iov++; 71 uio->uio_iovcnt--; 72 continue; 73 } 74 if (cnt > n) 75 cnt = n; 76 switch (uio->uio_segflg) { 77 78 case UIO_USERSPACE: 79 if (uio->uio_rw == UIO_READ) 80 error = copyout(cp, iov->iov_base, cnt); 81 else 82 error = copyin(iov->iov_base, cp, cnt); 83 if (error) 84 return (error); 85 break; 86 87 case UIO_SYSSPACE: 88 if (uio->uio_rw == UIO_READ) 89 bcopy((caddr_t)cp, iov->iov_base, cnt); 90 else 91 bcopy(iov->iov_base, (caddr_t)cp, cnt); 92 break; 93 } 94 iov->iov_base += cnt; 95 iov->iov_len -= cnt; 96 uio->uio_resid -= cnt; 97 uio->uio_offset += cnt; 98 cp += cnt; 99 n -= cnt; 100 } 101 return (error); 102 } 103 104 /* 105 * Give next character to user as result of read. 106 */ 107 int 108 ureadc(c, uio) 109 register int c; 110 register struct uio *uio; 111 { 112 register struct iovec *iov; 113 114 if (uio->uio_resid <= 0) 115 panic("ureadc: non-positive resid"); 116 again: 117 if (uio->uio_iovcnt <= 0) 118 panic("ureadc: non-positive iovcnt"); 119 iov = uio->uio_iov; 120 if (iov->iov_len <= 0) { 121 uio->uio_iovcnt--; 122 uio->uio_iov++; 123 goto again; 124 } 125 switch (uio->uio_segflg) { 126 127 case UIO_USERSPACE: 128 if (subyte(iov->iov_base, c) < 0) 129 return (EFAULT); 130 break; 131 132 case UIO_SYSSPACE: 133 *(char *)iov->iov_base = c; 134 break; 135 } 136 iov->iov_base++; 137 iov->iov_len--; 138 uio->uio_resid--; 139 uio->uio_offset++; 140 return (0); 141 } 142 143 /* 144 * General routine to allocate a hash table. 145 */ 146 void * 147 hashinit(elements, type, hashmask) 148 int elements, type; 149 u_long *hashmask; 150 { 151 long hashsize; 152 LIST_HEAD(generic, generic) *hashtbl; 153 int i; 154 155 if (elements <= 0) 156 panic("hashinit: bad cnt"); 157 for (hashsize = 1; hashsize <= elements; hashsize <<= 1) 158 continue; 159 hashsize >>= 1; 160 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); 161 for (i = 0; i < hashsize; i++) 162 LIST_INIT(&hashtbl[i]); 163 *hashmask = hashsize - 1; 164 return (hashtbl); 165 } 166 167 /* 168 * "Shutdown hook" types, functions, and variables. 169 */ 170 171 struct shutdownhook_desc { 172 LIST_ENTRY(shutdownhook_desc) sfd_list; 173 void (*sfd_fn) __P((void *)); 174 void *sfd_arg; 175 }; 176 177 LIST_HEAD(, shutdownhook_desc) shutdownhook_list; 178 179 int shutdownhooks_done; 180 181 void * 182 shutdownhook_establish(fn, arg) 183 void (*fn) __P((void *)); 184 void *arg; 185 { 186 struct shutdownhook_desc *ndp; 187 188 ndp = (struct shutdownhook_desc *) 189 malloc(sizeof (*ndp), M_DEVBUF, M_NOWAIT); 190 if (ndp == NULL) 191 return NULL; 192 193 ndp->sfd_fn = fn; 194 ndp->sfd_arg = arg; 195 LIST_INSERT_HEAD(&shutdownhook_list, ndp, sfd_list); 196 197 return (ndp); 198 } 199 200 void 201 shutdownhook_disestablish(vhook) 202 void *vhook; 203 { 204 #ifdef DIAGNOSTIC 205 struct shutdownhook_desc *dp; 206 207 for (dp = shutdownhook_list.lh_first; dp != NULL; 208 dp = dp->sfd_list.le_next) 209 if (dp == vhook) 210 break; 211 if (dp == NULL) 212 panic("shutdownhook_disestablish: hook not established"); 213 #endif 214 215 LIST_REMOVE((struct shutdownhook_desc *)vhook, sfd_list); 216 } 217 218 /* 219 * Run shutdown hooks. Should be invoked immediately before the 220 * system is halted or rebooted, i.e. after file systems unmounted, 221 * after crash dump done, etc. 222 */ 223 void 224 doshutdownhooks() 225 { 226 struct shutdownhook_desc *dp; 227 228 if (shutdownhooks_done) 229 return; 230 231 for (dp = shutdownhook_list.lh_first; dp != NULL; dp = 232 dp->sfd_list.le_next) 233 (*dp->sfd_fn)(dp->sfd_arg); 234 } 235