2 * Parts Copyright (c) 1995 Terrence R. Lambert
3 * Copyright (c) 1995 Julian R. Elischer
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
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
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
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>
43 #include <sys/vnode.h>
44 #include <sys/queue.h>
45 #include <machine/stdarg.h>
47 #define cdevsw_ALLOCSTART (NUMCDEVSW/2)
49 struct cdevsw *cdevsw[NUMCDEVSW];
51 static int bmaj2cmaj[NUMCDEVSW];
53 MALLOC_DEFINE(M_DEVT, "dev_t", "dev_t storage");
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
62 /* The number of dev_t's we can create before malloc(9) kick in. */
65 static struct specinfo devt_stash[DEVT_STASH];
67 static LIST_HEAD(, specinfo) dev_hash[DEVT_HASH];
69 static LIST_HEAD(, specinfo) dev_free;
71 devfs_create_t *devfs_create_hook;
72 devfs_remove_t *devfs_remove_hook;
75 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
81 return (dev->si_devsw);
82 return(cdevsw[major(dev)]);
90 cdevsw_add(struct cdevsw *newentry)
96 for (i = 0; i < NUMCDEVSW; i++)
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);
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);
112 if (newentry->d_bmaj >= 0 && (newentry->d_flags & D_DISK) == 0) {
113 printf("ERROR: \"%s\" bmaj but is not a disk\n",
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);
123 cdevsw[newentry->d_maj] = newentry;
125 if (newentry->d_bmaj < 0)
128 if (bmaj2cmaj[newentry->d_bmaj] != 254) {
129 printf("WARNING: \"%s\" is usurping \"%s\"'s bmaj\n",
131 cdevsw[bmaj2cmaj[newentry->d_bmaj]]->d_name);
133 bmaj2cmaj[newentry->d_bmaj] = newentry->d_maj;
138 * Remove a cdevsw entry
142 cdevsw_remove(struct cdevsw *oldentry)
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);
150 cdevsw[oldentry->d_maj] = NULL;
152 if (oldentry->d_bmaj >= 0 && oldentry->d_bmaj < NUMCDEVSW)
153 bmaj2cmaj[oldentry->d_bmaj] = 254;
159 * dev_t and u_dev_t primitives
167 return((x->si_udev >> 8) & 0xff);
175 return(x->si_udev & 0xffff00ff);
186 return ((i & 0xff) | (i >> 8));
190 makebdev(int x, int y)
193 if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
194 Debugger("makebdev of NOUDEV");
195 return (makedev(bmaj2cmaj[x], y));
199 makedev(int x, int y)
206 if (x == umajor(NOUDEV) && y == uminor(NOUDEV))
207 Debugger("makedev of NOUDEV");
209 hash = udev % DEVT_HASH;
210 LIST_FOREACH(si, &dev_hash[hash], si_hash) {
211 if (si->si_udev == udev)
214 if (stashed >= DEVT_STASH) {
215 MALLOC(si, struct specinfo *, sizeof(*si), M_DEVT,
217 bzero(si, sizeof(*si));
218 } else if (LIST_FIRST(&dev_free)) {
219 si = LIST_FIRST(&dev_free);
220 LIST_REMOVE(si, si_hash);
222 si = devt_stash + stashed++;
223 si->si_flags |= SI_STASHED;
226 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
237 if (SLIST_FIRST(&dev->si_hlist))
239 if (dev->si_devsw || dev->si_drv1 || dev->si_drv2)
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);
260 udev2dev(udev_t x, int b)
267 return makedev(umajor(x), uminor(x));
269 return makebdev(umajor(x), uminor(x));
271 Debugger("udev2dev(...,X)");
279 return(dev & 0xffff00ff);
285 return((dev & 0xff00) >> 8);
289 makeudev(int x, int y)
291 return ((x << 8) | y);
295 make_dev(struct cdevsw *devsw, int minor, uid_t uid, gid_t gid, int perms, char *fmt, ...)
301 dev = makedev(devsw->d_maj, minor);
303 i = kvprintf(fmt, NULL, dev->si_name, 32, ap);
304 dev->si_name[i] = '\0';
306 dev->si_devsw = devsw;
308 if (devfs_create_hook)
309 devfs_create_hook(dev, uid, gid, perms);
314 destroy_dev(dev_t dev)
316 if (devfs_remove_hook)
317 devfs_remove_hook(dev);
330 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
333 sprintf(p, "#%s/", devsw(dev)->d_name);
335 sprintf(p, "#%d/", major(dev));
338 if (mynor < 0 || mynor > 255)
339 sprintf(p, "%#x", (u_int)mynor);
341 sprintf(p, "%d", mynor);
343 return (dev->si_name);