| 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: src/sys/kern/kern_conf.c,v 1.73.2.3 2003/03/10 02:18:25 imp Exp $ |
| 34 | * $DragonFly: src/sys/kern/kern_conf.c,v 1.4 2003/07/22 17:03:33 dillon Exp $ |
| 35 | */ |
| 36 | |
| 37 | #include <sys/param.h> |
| 38 | #include <sys/kernel.h> |
| 39 | #include <sys/sysctl.h> |
| 40 | #include <sys/systm.h> |
| 41 | #include <sys/module.h> |
| 42 | #include <sys/malloc.h> |
| 43 | #include <sys/conf.h> |
| 44 | #include <sys/vnode.h> |
| 45 | #include <sys/queue.h> |
| 46 | #include <sys/device.h> |
| 47 | #include <machine/stdarg.h> |
| 48 | |
| 49 | #define cdevsw_ALLOCSTART (NUMCDEVSW/2) |
| 50 | |
| 51 | MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage"); |
| 52 | |
| 53 | /* |
| 54 | * This is the number of hash-buckets. Experiements with 'real-life' |
| 55 | * udev_t's show that a prime halfway between two powers of two works |
| 56 | * best. |
| 57 | */ |
| 58 | #define DEVT_HASH 83 |
| 59 | |
| 60 | /* The number of dev_t's we can create before malloc(9) kick in. */ |
| 61 | #define DEVT_STASH 50 |
| 62 | |
| 63 | static struct specinfo devt_stash[DEVT_STASH]; |
| 64 | |
| 65 | static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH]; |
| 66 | |
| 67 | static LIST_HEAD(, specinfo) dev_free; |
| 68 | |
| 69 | static int free_devt; |
| 70 | SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, ""); |
| 71 | |
| 72 | /* |
| 73 | * dev_t and u_dev_t primitives |
| 74 | */ |
| 75 | |
| 76 | int |
| 77 | major(dev_t x) |
| 78 | { |
| 79 | if (x == NODEV) |
| 80 | return NOUDEV; |
| 81 | return((x->si_udev >> 8) & 0xff); |
| 82 | } |
| 83 | |
| 84 | int |
| 85 | minor(dev_t x) |
| 86 | { |
| 87 | if (x == NODEV) |
| 88 | return NOUDEV; |
| 89 | return(x->si_udev & 0xffff00ff); |
| 90 | } |
| 91 | |
| 92 | int |
| 93 | lminor(dev_t x) |
| 94 | { |
| 95 | int i; |
| 96 | |
| 97 | if (x == NODEV) |
| 98 | return NOUDEV; |
| 99 | i = minor(x); |
| 100 | return ((i & 0xff) | (i >> 8)); |
| 101 | } |
| 102 | |
| 103 | dev_t |
| 104 | makedev(int x, int y) |
| 105 | { |
| 106 | struct specinfo *si; |
| 107 | udev_t udev; |
| 108 | int hash; |
| 109 | static int stashed; |
| 110 | |
| 111 | if (x == umajor(NOUDEV) && y == uminor(NOUDEV)) |
| 112 | Debugger("makedev of NOUDEV"); |
| 113 | udev = (x << 8) | y; |
| 114 | hash = udev % DEVT_HASH; |
| 115 | LIST_FOREACH(si, &dev_hash[hash], si_hash) { |
| 116 | if (si->si_udev == udev) |
| 117 | return (si); |
| 118 | } |
| 119 | if (stashed >= DEVT_STASH) { |
| 120 | MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT, |
| 121 | M_USE_RESERVE); |
| 122 | bzero(si, sizeof(*si)); |
| 123 | } else if (LIST_FIRST(&dev_free)) { |
| 124 | si = LIST_FIRST(&dev_free); |
| 125 | LIST_REMOVE(si, si_hash); |
| 126 | } else { |
| 127 | si = devt_stash + stashed++; |
| 128 | si->si_flags |= SI_STASHED; |
| 129 | } |
| 130 | si->si_udev = udev; |
| 131 | LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash); |
| 132 | return (si); |
| 133 | } |
| 134 | |
| 135 | void |
| 136 | freedev(dev_t dev) |
| 137 | { |
| 138 | int hash; |
| 139 | |
| 140 | if (!free_devt) |
| 141 | return; |
| 142 | if (SLIST_FIRST(&dev->si_hlist)) |
| 143 | return; |
| 144 | if (dev->si_devsw || dev->si_drv1 || dev->si_drv2) |
| 145 | return; |
| 146 | hash = dev->si_udev % DEVT_HASH; |
| 147 | LIST_REMOVE(dev, si_hash); |
| 148 | if (dev->si_flags & SI_STASHED) { |
| 149 | bzero(dev, sizeof(*dev)); |
| 150 | LIST_INSERT_HEAD(&dev_free, dev, si_hash); |
| 151 | } else { |
| 152 | FREE(dev, M_DEVT); |
| 153 | } |
| 154 | } |
| 155 | |
| 156 | udev_t |
| 157 | dev2udev(dev_t x) |
| 158 | { |
| 159 | if (x == NODEV) |
| 160 | return NOUDEV; |
| 161 | return (x->si_udev); |
| 162 | } |
| 163 | |
| 164 | dev_t |
| 165 | udev2dev(udev_t x, int b) |
| 166 | { |
| 167 | |
| 168 | if (x == NOUDEV) |
| 169 | return (NODEV); |
| 170 | switch (b) { |
| 171 | case 0: |
| 172 | return makedev(umajor(x), uminor(x)); |
| 173 | case 1: |
| 174 | printf("udev2dev: attempt to lookup block dev(%d)", x); |
| 175 | return NODEV; |
| 176 | default: |
| 177 | Debugger("udev2dev(...,X)"); |
| 178 | return NODEV; |
| 179 | } |
| 180 | } |
| 181 | |
| 182 | int |
| 183 | uminor(udev_t dev) |
| 184 | { |
| 185 | return(dev & 0xffff00ff); |
| 186 | } |
| 187 | |
| 188 | int |
| 189 | umajor(udev_t dev) |
| 190 | { |
| 191 | return((dev & 0xff00) >> 8); |
| 192 | } |
| 193 | |
| 194 | udev_t |
| 195 | makeudev(int x, int y) |
| 196 | { |
| 197 | return ((x << 8) | y); |
| 198 | } |
| 199 | |
| 200 | dev_t |
| 201 | make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, const char *fmt, ...) |
| 202 | { |
| 203 | dev_t dev; |
| 204 | va_list ap; |
| 205 | int i; |
| 206 | |
| 207 | compile_devsw(devsw); |
| 208 | dev = makedev(devsw->d_maj, minor); |
| 209 | va_start(ap, fmt); |
| 210 | i = kvprintf(fmt, NULL, dev->si_name, 32, ap); |
| 211 | dev->si_name[i] = '\0'; |
| 212 | va_end(ap); |
| 213 | dev->si_devsw = devsw; |
| 214 | |
| 215 | return (dev); |
| 216 | } |
| 217 | |
| 218 | void |
| 219 | destroy_dev(dev_t dev) |
| 220 | { |
| 221 | dev->si_drv1 = 0; |
| 222 | dev->si_drv2 = 0; |
| 223 | dev->si_devsw = 0; |
| 224 | freedev(dev); |
| 225 | } |
| 226 | |
| 227 | const char * |
| 228 | devtoname(dev_t dev) |
| 229 | { |
| 230 | int mynor; |
| 231 | int len; |
| 232 | char *p; |
| 233 | const char *dname; |
| 234 | |
| 235 | if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') { |
| 236 | p = dev->si_name; |
| 237 | len = sizeof(dev->si_name); |
| 238 | if ((dname = dev_dname(dev)) != NULL) |
| 239 | snprintf(p, len, "#%s/", dname); |
| 240 | else |
| 241 | snprintf(p, len, "#%d/", major(dev)); |
| 242 | len -= strlen(p); |
| 243 | p += strlen(p); |
| 244 | mynor = minor(dev); |
| 245 | if (mynor < 0 || mynor > 255) |
| 246 | snprintf(p, len, "%#x", (u_int)mynor); |
| 247 | else |
| 248 | snprintf(p, len, "%d", mynor); |
| 249 | } |
| 250 | return (dev->si_name); |
| 251 | } |