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 * $FreeBSD$ 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 49 struct cdevsw *cdevsw[NUMCDEVSW]; 50 51 static int bmaj2cmaj[NUMCDEVSW]; 52 53 MALLOC_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 65 static struct specinfo devt_stash[DEVT_STASH]; 66 67 static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH]; 68 69 static LIST_HEAD(, specinfo) dev_free; 70 71 devfs_create_t *devfs_create_hook; 72 devfs_remove_t *devfs_remove_hook; 73 74 static int free_devt; 75 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); 76 77 struct cdevsw * 78 devsw(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 89 int 90 cdevsw_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 */ 140 141 int 142 cdevsw_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 */ 161 162 int 163 major(dev_t x) 164 { 165 if (x == NODEV) 166 return NOUDEV; 167 return((x->si_udev >> 8) & 0xff); 168 } 169 170 int 171 minor(dev_t x) 172 { 173 if (x == NODEV) 174 return NOUDEV; 175 return(x->si_udev & 0xffff00ff); 176 } 177 178 int 179 lminor(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 } 188 189 dev_t 190 makebdev(int x, int y) 191 { 192 193 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 194 Debugger("makebdev of NOUDEV"); 195 return (makedev(bmaj2cmaj[x], y)); 196 } 197 198 dev_t 199 makedev(int x, int y) 200 { 201 struct specinfo *si; 202 udev_t udev; 203 int hash; 204 static int stashed; 205 206 if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) 207 Debugger("makedev of NOUDEV"); 208 udev = (x << 8) | y; 209 hash = udev % DEVT_HASH; 210 LIST_FOREACH(si, &dev_hash[hash], si_hash) { 211 if (si->si_udev == udev) 212 return (si); 213 } 214 if (stashed >= DEVT_STASH) { 215 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, 216 M_USE_RESERVE); 217 bzero(si, sizeof(*si)); 218 } else if (LIST_FIRST(&dev_free)) { 219 si = LIST_FIRST(&dev_free); 220 LIST_REMOVE(si, si_hash); 221 } else { 222 si = devt_stash + stashed++; 223 si->si_flags |= SI_STASHED; 224 } 225 si->si_udev = udev; 226 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); 227 return (si); 228 } 229 230 void 231 freedev(dev_t dev) 232 { 233 int hash; 234 235 if (!free_devt) 236 return; 237 if (SLIST_FIRST(&dev->si_hlist)) 238 return; 239 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) 240 return; 241 hash = dev->si_udev % DEVT_HASH; 242 LIST_REMOVE(dev, si_hash); 243 if (dev->si_flags & SI_STASHED) { 244 bzero(dev, sizeof(*dev)); 245 LIST_INSERT_HEAD(&dev_free, dev, si_hash); 246 } else { 247 FREE(dev, M_DEVT); 248 } 249 } 250 251 udev_t 252 dev2udev(dev_t x) 253 { 254 if (x == NODEV) 255 return NOUDEV; 256 return (x->si_udev); 257 } 258 259 dev_t 260 udev2dev(udev_t x, int b) 261 { 262 263 if (x == NOUDEV) 264 return (NODEV); 265 switch (b) { 266 case 0: 267 return makedev(umajor(x), uminor(x)); 268 case 1: 269 return makebdev(umajor(x), uminor(x)); 270 default: 271 Debugger("udev2dev(...,X)"); 272 return NODEV; 273 } 274 } 275 276 int 277 uminor(udev_t dev) 278 { 279 return(dev & 0xffff00ff); 280 } 281 282 int 283 umajor(udev_t dev) 284 { 285 return((dev & 0xff00) >> 8); 286 } 287 288 udev_t 289 makeudev(int x, int y) 290 { 291 return ((x << 8) | y); 292 } 293 294 dev_t 295 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...) 296 { 297 dev_t dev; 298 va_list ap; 299 int i; 300 301 dev = makedev(devsw->d_maj, minor); 302 va_start(ap, fmt); 303 i = kvprintf(fmt, NULL, dev->si_name, 32, ap); 304 dev->si_name[i] = '\0'; 305 va_end(ap); 306 dev->si_devsw = devsw; 307 308 if (devfs_create_hook) 309 devfs_create_hook(dev, uid, gid, perms); 310 return (dev); 311 } 312 313 void 314 destroy_dev(dev_t dev) 315 { 316 if (devfs_remove_hook) 317 devfs_remove_hook(dev); 318 dev->si_drv1 = 0; 319 dev->si_drv2 = 0; 320 dev->si_devsw = 0; 321 freedev(dev); 322 } 323 324 const char * 325 devtoname(dev_t dev) 326 { 327 char *p; 328 int mynor; 329 330 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { 331 p = dev->si_name; 332 if (devsw(dev)) 333 sprintf(p, "#%s/", devsw(dev)->d_name); 334 else 335 sprintf(p, "#%d/", major(dev)); 336 p += strlen(p); 337 mynor = minor(dev); 338 if (mynor < 0 || mynor > 255) 339 sprintf(p, "%#x", (u_int)mynor); 340 else 341 sprintf(p, "%d", mynor); 342 } 343 return (dev->si_name); 344 } 345