subr_hash.c revision 7683
1/* 2 * Copyright (c) 1982, 1986, 1991, 1993 3 * The Regents of the University of California. All rights reserved. 4 * (c) UNIX System Laboratories, Inc. 5 * All or some portions of this file are derived from material licensed 6 * to the University of California by American Telephone and Telegraph 7 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 8 * the permission of UNIX System Laboratories, Inc. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. All advertising materials mentioning features or use of this software 19 * must display the following acknowledgement: 20 * This product includes software developed by the University of 21 * California, Berkeley and its contributors. 22 * 4. Neither the name of the University nor the names of its contributors 23 * may be used to endorse or promote products derived from this software 24 * without specific prior written permission. 25 * 26 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 27 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 28 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 29 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 30 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 31 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 32 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 33 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 34 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 35 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 36 * SUCH DAMAGE. 37 * 38 * @(#)kern_subr.c 8.3 (Berkeley) 1/21/94 39 * $Id: kern_subr.c,v 1.5 1995/04/04 02:01:12 davidg Exp $ 40 */ 41 42#include <sys/param.h> 43#include <sys/systm.h> 44#include <sys/proc.h> 45#include <sys/malloc.h> 46#include <sys/queue.h> 47 48int 49uiomove(cp, n, uio) 50 register caddr_t cp; 51 register int n; 52 register struct uio *uio; 53{ 54 register struct iovec *iov; 55 u_int cnt; 56 int error; 57 58#ifdef DIAGNOSTIC 59 if (uio->uio_rw != UIO_READ && uio->uio_rw != UIO_WRITE) 60 panic("uiomove: mode"); 61 if (uio->uio_segflg == UIO_USERSPACE && uio->uio_procp != curproc) 62 panic("uiomove proc"); 63#endif 64 while (n > 0 && uio->uio_resid) { 65 iov = uio->uio_iov; 66 cnt = iov->iov_len; 67 if (cnt == 0) { 68 uio->uio_iov++; 69 uio->uio_iovcnt--; 70 continue; 71 } 72 if (cnt > n) 73 cnt = n; 74 75 switch (uio->uio_segflg) { 76 77 case UIO_USERSPACE: 78 case UIO_USERISPACE: 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 case UIO_NOCOPY: 94 break; 95 } 96 iov->iov_base += cnt; 97 iov->iov_len -= cnt; 98 uio->uio_resid -= cnt; 99 uio->uio_offset += cnt; 100 cp += cnt; 101 n -= cnt; 102 } 103 return (0); 104} 105 106/* 107 * Give next character to user as result of read. 108 */ 109int 110ureadc(c, uio) 111 register int c; 112 register struct uio *uio; 113{ 114 register struct iovec *iov; 115 116again: 117 if (uio->uio_iovcnt == 0 || uio->uio_resid == 0) 118 panic("ureadc"); 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 *iov->iov_base = c; 134 break; 135 136 case UIO_USERISPACE: 137 if (suibyte(iov->iov_base, c) < 0) 138 return (EFAULT); 139 break; 140 } 141 iov->iov_base++; 142 iov->iov_len--; 143 uio->uio_resid--; 144 uio->uio_offset++; 145 return (0); 146} 147 148#ifdef vax /* unused except by ct.c, other oddities XXX */ 149/* 150 * Get next character written in by user from uio. 151 */ 152int 153uwritec(uio) 154 struct uio *uio; 155{ 156 register struct iovec *iov; 157 register int c; 158 159 if (uio->uio_resid <= 0) 160 return (-1); 161again: 162 if (uio->uio_iovcnt <= 0) 163 panic("uwritec"); 164 iov = uio->uio_iov; 165 if (iov->iov_len == 0) { 166 uio->uio_iov++; 167 if (--uio->uio_iovcnt == 0) 168 return (-1); 169 goto again; 170 } 171 switch (uio->uio_segflg) { 172 173 case UIO_USERSPACE: 174 c = fubyte(iov->iov_base); 175 break; 176 177 case UIO_SYSSPACE: 178 c = *(u_char *) iov->iov_base; 179 break; 180 181 case UIO_USERISPACE: 182 c = fuibyte(iov->iov_base); 183 break; 184 } 185 if (c < 0) 186 return (-1); 187 iov->iov_base++; 188 iov->iov_len--; 189 uio->uio_resid--; 190 uio->uio_offset++; 191 return (c); 192} 193#endif /* vax */ 194 195/* 196 * General routine to allocate a hash table. 197 */ 198void * 199hashinit(elements, type, hashmask) 200 int elements, type; 201 u_long *hashmask; 202{ 203 long hashsize; 204 LIST_HEAD(generic, generic) *hashtbl; 205 int i; 206 207 if (elements <= 0) 208 panic("hashinit: bad cnt"); 209 for (hashsize = 1; hashsize <= elements; hashsize <<= 1) 210 continue; 211 hashsize >>= 1; 212 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); 213 for (i = 0; i < hashsize; i++) 214 LIST_INIT(&hashtbl[i]); 215 *hashmask = hashsize - 1; 216 return (hashtbl); 217} 218 219#define NPRIMES 27 220static int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531, 2039, 221 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143, 6653, 222 7159, 7673, 8191, 12281, 16381, 24571, 32749 }; 223 224/* 225 * General routine to allocate a prime number sized hash table. 226 */ 227void * 228phashinit(elements, type, nentries) 229 int elements, type; 230 u_long *nentries; 231{ 232 long hashsize; 233 LIST_HEAD(generic, generic) *hashtbl; 234 int i; 235 236 if (elements <= 0) 237 panic("hashinit: bad cnt"); 238 for (i = 1, hashsize = primes[1]; hashsize <= elements;) { 239 i++; 240 if (i == NPRIMES) 241 break; 242 hashsize = primes[i]; 243 } 244 hashsize = primes[i - 1]; 245 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK); 246 for (i = 0; i < hashsize; i++) 247 LIST_INIT(&hashtbl[i]); 248 *nentries = hashsize; 249 return (hashtbl); 250} 251