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
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 1.23 2007/05/09 00:53:34 dillon Exp $
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>
44 #include <sys/vnode.h>
45 #include <sys/queue.h>
46 #include <sys/device.h>
47 #include <machine/stdarg.h>
49 #include <sys/sysref2.h>
51 #include <vfs/devfs/devfs.h>
54 static void cdev_terminate(struct cdev *dev);
56 MALLOC_DEFINE(M_DEVT, "cdev_t", "dev_t storage");
59 * SYSREF Integration - reference counting, allocation,
60 * sysid and syslink integration.
62 static struct sysref_class cdev_sysref_class = {
65 .proto = SYSREF_PROTO_DEV,
66 .offset = offsetof(struct cdev, si_sysref),
67 .objsize = sizeof(struct cdev),
71 .terminate = (sysref_terminate_func_t)cdev_terminate
76 * This is the number of hash-buckets. Experiements with 'real-life'
77 * udev_t's show that a prime halfway between two powers of two works
80 #define DEVT_HASH 128 /* must be power of 2 */
81 static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
84 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
85 int dev_ref_debug = 0;
86 SYSCTL_INT(_debug, OID_AUTO, dev_refs, CTLFLAG_RW, &dev_ref_debug, 0, "");
89 * cdev_t and u_dev_t primitives. Note that the major number is always
90 * extracted from si_umajor, not from si_devsw, because si_devsw is replaced
91 * when a device is destroyed.
98 return(dev->si_umajor);
106 return(dev->si_uminor);
110 * Compatibility function with old udev_t format to convert the
111 * non-consecutive minor space into a consecutive minor space.
123 return ((y & 0xff) | (y >> 8));
127 * This is a bit complex because devices are always created relative to
128 * a particular cdevsw, including 'hidden' cdevsw's (such as the raw device
129 * backing a disk subsystem overlay), so we have to compare both the
130 * devsw and udev fields to locate the correct device.
132 * The device is created if it does not already exist. If SI_ADHOC is not
133 * set the device will be referenced (once) and SI_ADHOC will be set.
134 * The caller must explicitly add additional references to the device if
135 * the caller wishes to track additional references.
137 * NOTE: The passed ops vector must normally match the device. This is
138 * because the kernel may create shadow devices that are INVISIBLE TO
139 * USERLAND. For example, the block device backing a disk is created
140 * as a shadow underneath the user-visible disklabel management device.
141 * Sometimes a device ops vector can be overridden, such as by /dev/console.
142 * In this case and this case only we allow a match when the ops vector
143 * otherwise would not match.
147 __devthash(int x, int y)
149 return(((x << 2) ^ y) & (DEVT_HASH - 1));
154 hashdev(struct dev_ops *ops, int x, int y, int allow_intercept)
159 hash = __devthash(x, y);
160 LIST_FOREACH(si, &dev_hash[hash], si_hash) {
161 if (si->si_umajor == x && si->si_uminor == y) {
162 if (si->si_ops == ops)
164 if (allow_intercept && (si->si_flags & SI_INTERCEPTED))
168 si = sysref_alloc(&cdev_sysref_class);
170 si->si_flags |= SI_HASHED | SI_ADHOC;
174 LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
175 sysref_activate(&si->si_sysref);
178 if (ops != &dead_dev_ops)
181 kprintf("create dev %p %s(minor=%08x) refs=%d\n",
182 si, devtoname(si), y,
183 si->si_sysref.refcnt);
189 * Convert a device pointer to an old style device number. Return NOUDEV
190 * if the device is invalid or if the device (maj,min) cannot be converted
191 * to an old style udev_t.
199 return (udev_t)dev->si_inode;
203 * Convert a device number to a device pointer. The device is referenced
204 * ad-hoc, meaning that the caller should call reference_dev() if it wishes
205 * to keep ahold of the returned structure long term.
207 * The returned device is associated with the currently installed cdevsw
208 * for the requested major number. NULL is returned if the major number
209 * has not been registered.
212 udev2dev(udev_t x, int b)
214 if (x == NOUDEV || b != 0)
217 return devfs_find_device_by_udev(x);
221 dev_is_good(cdev_t dev)
223 if (dev != NULL && dev->si_ops != &dead_dev_ops)
229 * Various user device number extraction and conversion routines
236 return(dev & 0xffff00ff);
244 return((dev & 0xff00) >> 8);
248 makeudev(int x, int y)
250 if ((x & 0xffffff00) || (y & 0x0000ff00))
252 return ((x << 8) | y);
256 * Create an internal or external device.
258 * This routine creates and returns an unreferenced ad-hoc entry for the
259 * device which will remain intact until the device is destroyed. If the
260 * caller intends to store the device pointer it must call reference_dev()
261 * to retain a real reference to the device.
263 * If an entry already exists, this function will set (or override)
264 * its cred requirements and name (XXX DEVFS interface).
267 make_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
268 int perms, const char *fmt, ...)
273 char dev_name[PATH_MAX+1];
276 * compile the cdevsw and install the device
278 compile_dev_ops(ops);
281 * Set additional fields (XXX DEVFS interface goes here)
284 i = kvcprintf(fmt, NULL, dev_name, 32, ap);
289 if ((devfs_dev = devfs_find_device_by_name(dev_name)) != NULL) {
290 kprintf("make_dev: Device %s already exists, returning old dev without creating new node\n", dev_name);
295 devfs_dev = devfs_new_cdev(ops, minor);
296 memcpy(devfs_dev->si_name, dev_name, i+1);
298 devfs_debug(DEVFS_DEBUG_INFO, "make_dev called for %s\n", devfs_dev->si_name);
299 devfs_create_dev(devfs_dev, uid, gid, perms);
306 make_only_devfs_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
307 int perms, const char *fmt, ...)
315 * compile the cdevsw and install the device
317 compile_dev_ops(ops);
318 devfs_dev = devfs_new_cdev(ops, minor);
321 * Set additional fields (XXX DEVFS interface goes here)
324 i = kvcprintf(fmt, NULL, devfs_dev->si_name, 32, ap);
325 devfs_dev->si_name[i] = '\0';
329 devfs_create_dev(devfs_dev, uid, gid, perms);
336 make_only_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
337 int perms, const char *fmt, ...)
345 * compile the cdevsw and install the device
347 compile_dev_ops(ops);
348 devfs_dev = devfs_new_cdev(ops, minor);
349 devfs_dev->si_perms = perms;
350 devfs_dev->si_uid = uid;
351 devfs_dev->si_gid = gid;
354 * Set additional fields (XXX DEVFS interface goes here)
357 i = kvcprintf(fmt, NULL, devfs_dev->si_name, 32, ap);
358 devfs_dev->si_name[i] = '\0';
361 reference_dev(devfs_dev);
367 destroy_only_dev(cdev_t dev)
369 devfs_destroy_cdev(dev);
374 * This function is similar to make_dev() but no cred information or name
378 make_adhoc_dev(struct dev_ops *ops, int minor)
382 dev = hashdev(ops, ops->head.maj, minor, FALSE);
387 * This function is similar to make_dev() except the new device is created
388 * using an old device as a template.
391 make_sub_dev(cdev_t odev, int minor)
395 dev = hashdev(odev->si_ops, odev->si_umajor, minor, FALSE);
398 * Copy cred requirements and name info XXX DEVFS.
400 if (dev->si_name[0] == 0 && odev->si_name[0])
401 bcopy(odev->si_name, dev->si_name, sizeof(dev->si_name));
406 * destroy_dev() removes the adhoc association for a device and revectors
407 * its ops to &dead_dev_ops.
409 * This routine releases the reference count associated with the ADHOC
410 * entry, plus releases the reference count held by the caller. What this
411 * means is that you should not call destroy_dev(make_dev(...)), because
412 * make_dev() does not bump the reference count (beyond what it needs to
413 * create the ad-hoc association). Any procedure that intends to destroy
414 * a device must have its own reference to it first.
417 destroy_dev(cdev_t dev)
422 devfs_debug(DEVFS_DEBUG_DEBUG,
423 "destroy_dev called for %s\n",
425 devfs_destroy_dev(dev);
430 * Destroy all ad-hoc device associations associated with a domain within a
431 * device switch. Only the minor numbers are included in the mask/match
434 * Unlike the ops functions whos link structures do not contain
435 * any major bits, this function scans through the dev list via
436 * si_umajor/si_uminor.
438 * The caller must not include any major bits in the match value.
441 destroy_all_devs(struct dev_ops *ops, u_int mask, u_int match)
447 for (i = 0; i < DEVT_HASH; ++i) {
448 ndev = LIST_FIRST(&dev_hash[i]);
449 while ((dev = ndev) != NULL) {
450 ndev = LIST_NEXT(dev, si_hash);
451 if (dev->si_ops == ops &&
452 ((u_int)dev->si_uminor & mask) == match
454 KKASSERT(dev->si_flags & SI_ADHOC);
464 make_dev_alias(cdev_t target, const char *fmt, ...)
466 char name[PATH_MAX + 1];
471 i = kvcprintf(fmt, NULL, name, 32, ap);
475 devfs_make_alias(name, target);
482 * Add a reference to a device. Callers generally add their own references
483 * when they are going to store a device node in a variable for long periods
484 * of time, to prevent a disassociation from free()ing the node.
486 * Also note that a caller that intends to call destroy_dev() must first
487 * obtain a reference on the device. The ad-hoc reference you get with
488 * make_dev() and friends is NOT sufficient to be able to call destroy_dev().
491 reference_dev(cdev_t dev)
493 //kprintf("reference_dev\n");
496 sysref_get(&dev->si_sysref);
498 kprintf("reference dev %p %s(minor=%08x) refs=%d\n",
499 dev, devtoname(dev), dev->si_uminor,
500 dev->si_sysref.refcnt);
507 * release a reference on a device. The device will be terminated when the
508 * last reference has been released.
510 * NOTE: we must use si_umajor to figure out the original major number,
511 * because si_ops could already be pointing at dead_dev_ops.
514 release_dev(cdev_t dev)
516 //kprintf("release_dev\n");
520 sysref_put(&dev->si_sysref);
525 cdev_terminate(struct cdev *dev)
530 kprintf("release dev %p %s(minor=%08x) refs=%d\n",
531 dev, devtoname(dev), dev->si_uminor,
532 dev->si_sysref.refcnt);
534 if (dev->si_flags & SI_ADHOC) {
535 kprintf("Warning: illegal final release on ADHOC"
536 " device %p(%s), the device was never"
538 dev, devtoname(dev));
541 if (dev->si_flags & SI_HASHED) {
542 kprintf("Warning: last release on device, no call"
543 " to destroy_dev() was made! dev %p(%s)\n",
544 dev, devtoname(dev));
549 if (SLIST_FIRST(&dev->si_hlist) != NULL) {
550 kprintf("Warning: last release on device, vnode"
551 " associations still exist! dev %p(%s)\n",
552 dev, devtoname(dev));
555 if (dev->si_ops && dev->si_ops != &dead_dev_ops) {
556 dev_ops_release(dev->si_ops);
560 sysref_put(&dev->si_sysref);
564 devtoname(cdev_t dev)
573 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
575 len = sizeof(dev->si_name);
576 if ((dname = dev_dname(dev)) != NULL)
577 ksnprintf(p, len, "#%s/", dname);
579 ksnprintf(p, len, "#%d/", major(dev));
583 if (mynor < 0 || mynor > 255)
584 ksnprintf(p, len, "%#x", (u_int)mynor);
586 ksnprintf(p, len, "%d", mynor);
588 return (dev->si_name);