kern_conf.c revision 53896
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 53896 1999-11-29 20:50:58Z phk $ 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 77struct cdevsw * 78devsw(dev_t dev) 79{ 80 if (dev->si_devsw) 81 return (dev->si_devsw); 82 return(cdevsw[major(dev)]); 83} 84 85/* 86 * Add a cdevsw entry 87 */ 88 89int 90cdevsw_add(struct cdevsw *newentry) 91{ 92 int i; 93 static int setup; 94 95 if (!setup) { 96 for (i = 0; i < NUMCDEVSW; i++) 97 if (!bmaj2cmaj[i]) 98 bmaj2cmaj[i] = 254; 99 setup++; 100 } 101 102 if (newentry->d_maj < 0 || newentry->d_maj >= NUMCDEVSW) { 103 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 104 newentry->d_name, newentry->d_maj); 105 return (EINVAL); 106 } 107 if (newentry->d_bmaj >= NUMCDEVSW) { 108 printf("%s: ERROR: driver has bogus cdevsw->d_bmaj = %d\n", 109 newentry->d_name, newentry->d_bmaj); 110 return (EINVAL); 111 } 112 if (newentry->d_bmaj >= 0 && (newentry->d_flags & D_DISK) == 0) { 113 printf("ERROR: \"%s\" bmaj but is not a disk\n", 114 newentry->d_name); 115 return (EINVAL); 116 } 117 118 if (cdevsw[newentry->d_maj]) { 119 printf("WARNING: \"%s\" is usurping \"%s\"'s cdevsw[]\n", 120 newentry->d_name, cdevsw[newentry->d_maj]->d_name); 121 } 122 123 cdevsw[newentry->d_maj] = newentry; 124 125 if (newentry->d_bmaj < 0) 126 return (0); 127 128 if (bmaj2cmaj[newentry->d_bmaj] != 254) { 129 printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n", 130 newentry->d_name, 131 cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name); 132 } 133 bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj; 134 return (0); 135} 136 137/* 138 * Remove a cdevsw entry 139 */ 140 141int 142cdevsw_remove(struct cdevsw *oldentry) 143{ 144 if (oldentry->d_maj < 0 || oldentry->d_maj >= NUMCDEVSW) { 145 printf("%s: ERROR: driver has bogus cdevsw->d_maj = %d\n", 146 oldentry->d_name, oldentry->d_maj); 147 return EINVAL; 148 } 149 150 cdevsw[oldentry->d_maj] = NULL; 151 152 if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW) 153 bmaj2cmaj[oldentry->d_bmaj] = 254; 154 155 return 0; 156} 157 158/* 159 * dev_t and u_dev_t primitives 160 */ 161 162int 163major(dev_t x) 164{ 165 if (x == NODEV) 166 return NOUDEV; 167 return((x->si_udev >> 8) & 0xff); 168} 169 170int 171minor(dev_t x) 172{ 173 if (x == NODEV) 174 return NOUDEV; 175 return(x->si_udev & 0xffff00ff); 176} 177 178int 179lminor(dev_t x) 180{ 181 int i; 182 183 if (x == NODEV) 184 return NOUDEV; 185 i = minor(x); 186 return ((i & 0xff) | (i >> 8)); 187} 188 189dev_t 190makebdev(int x, int y) 191{ 192 return (makedev(bmaj2cmaj[x], y)); 193} 194 195dev_t 196makedev(int x, int y) 197{ 198 struct specinfo *si; 199 udev_t udev; 200 int hash; 201 static int stashed; 202 203 udev = (x << 8) | y; 204 hash = udev % DEVT_HASH; 205 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 206 if (si->si_udev == udev) 207 return (si); 208 } 209 if (stashed >= DEVT_STASH) { 210 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, 211 M_USE_RESERVE); 212 bzero(si, sizeof(*si)); 213 } else if (LIST_FIRST(&dev_free)) { 214 si = LIST_FIRST(&dev_free); 215 LIST_REMOVE(si, si_hash); 216 } else { 217 si = devt_stash + stashed++; 218 si->si_flags |= SI_STASHED; 219 } 220 si->si_udev = udev; 221 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 222 return (si); 223} 224 225void 226freedev(dev_t dev) 227{ 228 int hash; 229 230 if (!free_devt) 231 return; 232 if (SLIST_FIRST(&dev->si_hlist)) 233 return; 234 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 235 return; 236 hash = dev->si_udev % DEVT_HASH; 237 LIST_REMOVE(dev, si_hash); 238 if (dev->si_flags & SI_STASHED) { 239 bzero(dev, sizeof(*dev)); 240 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 241 } else { 242 FREE(dev, M_DEVT); 243 } 244} 245 246udev_t 247dev2udev(dev_t x) 248{ 249 if (x == NODEV) 250 return NOUDEV; 251 return (x->si_udev); 252} 253 254udev_t 255dev2budev(dev_t x) 256{ 257 if (x == NODEV) 258 return NOUDEV; 259 else 260 return makeudev(devsw(x)->d_bmaj, minor(x)); 261} 262 263dev_t 264udev2dev(udev_t x, int b) 265{ 266 switch (b) { 267 case 0: 268 return makedev(umajor(x), uminor(x)); 269 case 1: 270 return makebdev(umajor(x), uminor(x)); 271 default: 272 Debugger("udev2dev(...,X)"); 273 return NODEV; 274 } 275} 276 277int 278uminor(udev_t dev) 279{ 280 return(dev & 0xffff00ff); 281} 282 283int 284umajor(udev_t dev) 285{ 286 return((dev & 0xff00) >> 8); 287} 288 289udev_t 290makeudev(int x, int y) 291{ 292 return ((x << 8) | y); 293} 294 295dev_t 296make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...) 297{ 298 dev_t dev; 299 va_list ap; 300 int i; 301 302 dev = makedev(devsw->d_maj, minor); 303 va_start(ap, fmt); 304 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 305 dev->si_name[i] = '\0'; 306 va_end(ap); 307 dev->si_devsw = devsw; 308 309 if (devfs_create_hook) 310 devfs_create_hook(dev, uid, gid, perms); 311 return (dev); 312} 313 314void 315destroy_dev(dev_t dev) 316{ 317 if (devfs_remove_hook) 318 devfs_remove_hook(dev); 319 dev->si_drv1 = 0; 320 dev->si_drv2 = 0; 321 dev->si_devsw = 0; 322 freedev(dev); 323} 324 325const char * 326devtoname(dev_t dev) 327{ 328 char *p; 329 int mynor; 330 331 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 332 p = dev->si_name; 333 if (devsw(dev)) 334 sprintf(p, "#%s/", devsw(dev)->d_name); 335 else 336 sprintf(p, "#%d/", major(dev)); 337 p += strlen(p); 338 mynor = minor(dev); 339 if (mynor < 0 || mynor > 255) 340 sprintf(p, "%#x", (u_int)mynor); 341 else 342 sprintf(p, "%d", mynor); 343 } 344 return (dev->si_name); 345} 346