kern_conf.c revision 53006
1/*- 2 * Parts Copyright (c) 1995 Terrence R. Lambert 3 * Copyright (c) 1995 Julian R. Elischer 4 * All rights reserved. 5 * 6 * Redistribution and use in source and binary forms, with or without 7 * modification, are permitted provided that the following conditions 8 * are met: 9 * 1. Redistributions of source code must retain the above copyright 10 * notice, this list of conditions and the following disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 3. All advertising materials mentioning features or use of this software 15 * must display the following acknowledgement: 16 * This product includes software developed by Terrence R. Lambert. 17 * 4. The name Terrence R. Lambert may not be used to endorse or promote 18 * products derived from this software without specific prior written 19 * permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY 22 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 23 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 24 * ARE DISCLAIMED. IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE 25 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 26 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 27 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 28 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 29 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 30 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * $FreeBSD: head/sys/kern/kern_conf.c 53006 1999-11-08 08:10:00Z peter $ 34 */ 35 36#include <sys/param.h> 37#include <sys/kernel.h> 38#include <sys/sysctl.h> 39#include <sys/systm.h> 40#include <sys/module.h> 41#include <sys/malloc.h> 42#include <sys/conf.h> 43#include <sys/vnode.h> 44#include <sys/queue.h> 45#include <machine/stdarg.h> 46 47#define cdevsw_ALLOCSTART (NUMCDEVSW/2) 48 49struct cdevsw *cdevsw[NUMCDEVSW]; 50 51static int bmaj2cmaj[NUMCDEVSW]; 52 53MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); 54 55/* 56 * This is the number of hash-buckets. Experiements with 'real-life' 57 * udev_t's show that a prime halfway between two powers of two works 58 * best. 59 */ 60#define DEVT_HASH 83 61 62/* The number of dev_t's we can create before malloc(9) kick in. */ 63#define DEVT_STASH 50 64 65static struct specinfo devt_stash[DEVT_STASH]; 66 67static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH]; 68 69static LIST_HEAD(, specinfo) dev_free; 70 71devfs_create_t *devfs_create_hook; 72devfs_remove_t *devfs_remove_hook; 73 74static int free_devt; 75SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 76 77/* 78 * Routine to convert from character to block device number. 79 * 80 * A minimal stub routine can always return NODEV. 81 */ 82dev_t 83chrtoblk(dev_t dev) 84{ 85 struct cdevsw *cd; 86 87 if((cd = devsw(dev)) != NULL) { 88 if (cd->d_bmaj != -1) 89 return(makebdev(cd->d_bmaj,minor(dev))); 90 } 91 return(NODEV); 92} 93 94struct cdevsw * 95devsw(dev_t dev) 96{ 97 if (dev->si_devsw) 98 return (dev->si_devsw); 99 return(cdevsw[major(dev)]); 100} 101 102/* 103 * Add a cdevsw entry 104 */ 105 106int 107cdevsw_add(struct cdevsw *newentry) 108{ 109 int i; 110 static int setup; 111 112 if (!setup) { 113 for (i = 0; i < NUMCDEVSW; i++) 114 if (!bmaj2cmaj[i]) 115 bmaj2cmaj[i] = 254; 116 setup++; 117 } 118 119 if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) { 120 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 121 newentry->d_name, newentry->d_maj); 122 return (EINVAL); 123 } 124 if (newentry->d_bmaj >= NUMCDEVSW) { 125 printf("%s: ERROR: driver has bogus cdevsw->d_bmaj = %d\n", 126 newentry->d_name, newentry->d_bmaj); 127 return (EINVAL); 128 } 129 if (newentry->d_bmaj >= 0 && (newentry->d_flags & D_DISK) == 0) { 130 printf("ERROR: \"%s\" bmaj but is not a disk\n", 131 newentry->d_name); 132 return (EINVAL); 133 } 134 135 if (cdevsw[newentry->d_maj]) { 136 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n", 137 newentry->d_name, cdevsw[newentry->d_maj]->d_name); 138 } 139 140 cdevsw[newentry->d_maj] = newentry; 141 142 if (newentry->d_bmaj < 0) 143 return (0); 144 145 if (bmaj2cmaj[newentry->d_bmaj] != 254) { 146 printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n", 147 newentry->d_name, 148 cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name); 149 } 150 bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj; 151 return (0); 152} 153 154/* 155 * Remove a cdevsw entry 156 */ 157 158int 159cdevsw_remove(struct cdevsw *oldentry) 160{ 161 if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) { 162 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 163 oldentry->d_name, oldentry->d_maj); 164 return EINVAL; 165 } 166 167 cdevsw[oldentry->d_maj] = NULL; 168 169 if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW) 170 bmaj2cmaj[oldentry->d_bmaj] = 254; 171 172 return 0; 173} 174 175/* 176 * dev_t and u_dev_t primitives 177 */ 178 179int 180major(dev_t x) 181{ 182 if (x == NODEV) 183 return NOUDEV; 184 return((x->si_udev >> 8) & 0xff); 185} 186 187int 188minor(dev_t x) 189{ 190 if (x == NODEV) 191 return NOUDEV; 192 return(x->si_udev & 0xffff00ff); 193} 194 195int 196lminor(dev_t x) 197{ 198 int i; 199 200 if (x == NODEV) 201 return NOUDEV; 202 i = minor(x); 203 return ((i & 0xff) | (i >> 8)); 204} 205 206dev_t 207makebdev(int x, int y) 208{ 209 return (makedev(bmaj2cmaj[x], y)); 210} 211 212dev_t 213makedev(int x, int y) 214{ 215 struct specinfo *si; 216 udev_t udev; 217 int hash; 218 static int stashed; 219 220 udev = (x << 8) | y; 221 hash = udev % DEVT_HASH; 222 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 223 if (si->si_udev == udev) 224 return (si); 225 } 226 if (stashed >= DEVT_STASH) { 227 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, 228 M_USE_RESERVE); 229 bzero(si, sizeof(*si)); 230 } else if (LIST_FIRST(&dev_free)) { 231 si = LIST_FIRST(&dev_free); 232 LIST_REMOVE(si, si_hash); 233 } else { 234 si = devt_stash + stashed++; 235 si->si_flags |= SI_STASHED; 236 } 237 si->si_udev = udev; 238 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 239 return (si); 240} 241 242void 243freedev(dev_t dev) 244{ 245 int hash; 246 247 if (!free_devt) 248 return; 249 if (SLIST_FIRST(&dev->si_hlist)) 250 return; 251 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 252 return; 253 hash = dev->si_udev % DEVT_HASH; 254 LIST_REMOVE(dev, si_hash); 255 if (dev->si_flags & SI_STASHED) { 256 bzero(dev, sizeof(*dev)); 257 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 258 } else { 259 FREE(dev, M_DEVT); 260 } 261} 262 263udev_t 264dev2udev(dev_t x) 265{ 266 if (x == NODEV) 267 return NOUDEV; 268 return (x->si_udev); 269} 270 271udev_t 272dev2budev(dev_t x) 273{ 274 if (x == NODEV) 275 return NOUDEV; 276 else 277 return makeudev(devsw(x)->d_bmaj, minor(x)); 278} 279 280dev_t 281udev2dev(udev_t x, int b) 282{ 283 switch (b) { 284 case 0: 285 return makedev(umajor(x), uminor(x)); 286 case 1: 287 return makebdev(umajor(x), uminor(x)); 288 default: 289 Debugger("udev2dev(...,X)"); 290 return NODEV; 291 } 292} 293 294int 295uminor(udev_t dev) 296{ 297 return(dev & 0xffff00ff); 298} 299 300int 301umajor(udev_t dev) 302{ 303 return((dev & 0xff00) >> 8); 304} 305 306udev_t 307makeudev(int x, int y) 308{ 309 return ((x << 8) | y); 310} 311 312dev_t 313make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...) 314{ 315 dev_t dev; 316 va_list ap; 317 int i; 318 319 dev = makedev(devsw->d_maj, minor); 320 va_start(ap, fmt); 321 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 322 dev->si_name[i] = '\0'; 323 va_end(ap); 324 dev->si_devsw = devsw; 325 326 if (devfs_create_hook) 327 devfs_create_hook(dev, uid, gid, perms); 328 return (dev); 329} 330 331void 332destroy_dev(dev_t dev) 333{ 334 if (devfs_remove_hook) 335 devfs_remove_hook(dev); 336 dev->si_drv1 = 0; 337 dev->si_drv2 = 0; 338 dev->si_devsw = 0; 339 freedev(dev); 340} 341 342const char * 343devtoname(dev_t dev) 344{ 345 char *p; 346 int mynor; 347 348 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 349 p = dev->si_name; 350 if (devsw(dev)) 351 sprintf(p, "#%s/", devsw(dev)->d_name); 352 else 353 sprintf(p, "#%d/", major(dev)); 354 p += strlen(p); 355 mynor = minor(dev); 356 if (mynor < 0 || mynor > 255) 357 sprintf(p, "%#x", (u_int)mynor); 358 else 359 sprintf(p, "%d", mynor); 360 } 361 return (dev->si_name); 362} 363