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>
48 #include <machine/stdarg.h>
50 #include <sys/sysref2.h>
52 #include <vfs/devfs/devfs.h>
54 MALLOC_DEFINE(M_DEVT, "cdev_t", "dev_t storage");
57 SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
58 int dev_ref_debug = 0;
59 SYSCTL_INT(_debug, OID_AUTO, dev_refs, CTLFLAG_RW, &dev_ref_debug, 0, "");
62 * cdev_t and u_dev_t primitives. Note that the major number is always
63 * extracted from si_umajor, not from si_devsw, because si_devsw is replaced
64 * when a device is destroyed.
71 return(dev->si_umajor);
79 return(dev->si_uminor);
83 * Compatibility function with old udev_t format to convert the
84 * non-consecutive minor space into a consecutive minor space.
96 return ((y & 0xff) | (y >> 8));
100 * Convert a device pointer to an old style device number. Return NOUDEV
101 * if the device is invalid or if the device (maj,min) cannot be converted
102 * to an old style udev_t.
110 return (udev_t)dev->si_inode;
114 * Convert a device number to a device pointer. The device is referenced
115 * ad-hoc, meaning that the caller should call reference_dev() if it wishes
116 * to keep ahold of the returned structure long term.
118 * The returned device is associated with the currently installed cdevsw
119 * for the requested major number. NULL is returned if the major number
120 * has not been registered.
123 udev2dev(udev_t x, int b)
125 if (x == NOUDEV || b != 0)
128 return devfs_find_device_by_udev(x);
132 dev_is_good(cdev_t dev)
134 if (dev != NULL && dev->si_ops != &dead_dev_ops)
140 * Various user device number extraction and conversion routines
147 return(dev & 0xffff00ff);
155 return((dev & 0xff00) >> 8);
159 makeudev(int x, int y)
161 if ((x & 0xffffff00) || (y & 0x0000ff00))
163 return ((x << 8) | y);
167 * Create an internal or external device.
169 * This routine creates and returns an unreferenced ad-hoc entry for the
170 * device which will remain intact until the device is destroyed. If the
171 * caller intends to store the device pointer it must call reference_dev()
172 * to retain a real reference to the device.
174 * If an entry already exists, this function will set (or override)
175 * its cred requirements and name (XXX DEVFS interface).
178 make_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
179 int perms, const char *fmt, ...)
184 char dev_name[PATH_MAX+1];
187 * compile the cdevsw and install the device
189 compile_dev_ops(ops);
192 * Set additional fields (XXX DEVFS interface goes here)
195 i = kvcprintf(fmt, NULL, dev_name, 32, ap);
200 if ((devfs_dev = devfs_find_device_by_name(dev_name)) != NULL) {
201 kprintf("make_dev: Device %s already exists, returning old dev without creating new node\n", dev_name);
206 devfs_dev = devfs_new_cdev(ops, minor);
207 memcpy(devfs_dev->si_name, dev_name, i+1);
209 devfs_debug(DEVFS_DEBUG_INFO,
210 "make_dev called for %s\n",
212 devfs_create_dev(devfs_dev, uid, gid, perms);
219 make_only_devfs_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
220 int perms, const char *fmt, ...)
228 * compile the cdevsw and install the device
230 compile_dev_ops(ops);
231 devfs_dev = devfs_new_cdev(ops, minor);
234 * Set additional fields (XXX DEVFS interface goes here)
237 i = kvcprintf(fmt, NULL, devfs_dev->si_name, 32, ap);
238 devfs_dev->si_name[i] = '\0';
242 devfs_create_dev(devfs_dev, uid, gid, perms);
249 make_only_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
250 int perms, const char *fmt, ...)
258 * compile the cdevsw and install the device
260 compile_dev_ops(ops);
261 devfs_dev = devfs_new_cdev(ops, minor);
262 devfs_dev->si_perms = perms;
263 devfs_dev->si_uid = uid;
264 devfs_dev->si_gid = gid;
267 * Set additional fields (XXX DEVFS interface goes here)
270 i = kvcprintf(fmt, NULL, devfs_dev->si_name, 32, ap);
271 devfs_dev->si_name[i] = '\0';
274 reference_dev(devfs_dev);
280 destroy_only_dev(cdev_t dev)
288 * destroy_dev() removes the adhoc association for a device and revectors
289 * its ops to &dead_dev_ops.
291 * This routine releases the reference count associated with the ADHOC
292 * entry, plus releases the reference count held by the caller. What this
293 * means is that you should not call destroy_dev(make_dev(...)), because
294 * make_dev() does not bump the reference count (beyond what it needs to
295 * create the ad-hoc association). Any procedure that intends to destroy
296 * a device must have its own reference to it first.
299 destroy_dev(cdev_t dev)
302 devfs_debug(DEVFS_DEBUG_DEBUG,
303 "destroy_dev called for %s\n",
305 devfs_destroy_dev(dev);
310 * Make sure all asynchronous disk and devfs related operations have
313 * Typically called prior to mountroot to ensure that all disks have
314 * been completely probed and on module unload to ensure that ops
315 * structures have been dereferenced.
327 make_dev_alias(cdev_t target, const char *fmt, ...)
329 char name[PATH_MAX + 1];
334 i = kvcprintf(fmt, NULL, name, 32, ap);
338 devfs_make_alias(name, target);
343 extern struct dev_ops default_dev_ops;
346 make_autoclone_dev(struct dev_ops *ops, struct devfs_bitmap *bitmap,
347 d_clone_t *nhandler, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
350 char name[PATH_MAX + 1];
355 i = kvcprintf(fmt, NULL, name, 32, ap);
360 devfs_clone_bitmap_init(bitmap);
362 devfs_clone_handler_add(name, nhandler);
363 dev = make_dev(&default_dev_ops, 0xffff00ff, uid, gid, perms, name);
369 destroy_autoclone_dev(cdev_t dev, struct devfs_bitmap *bitmap)
374 devfs_clone_handler_del(dev->si_name);
377 devfs_clone_bitmap_uninit(bitmap);
384 * Add a reference to a device. Callers generally add their own references
385 * when they are going to store a device node in a variable for long periods
386 * of time, to prevent a disassociation from free()ing the node.
388 * Also note that a caller that intends to call destroy_dev() must first
389 * obtain a reference on the device. The ad-hoc reference you get with
390 * make_dev() and friends is NOT sufficient to be able to call destroy_dev().
393 reference_dev(cdev_t dev)
395 //kprintf("reference_dev\n");
398 sysref_get(&dev->si_sysref);
399 if (dev_ref_debug & 2) {
400 kprintf("reference dev %p %s(minor=%08x) refs=%d\n",
401 dev, devtoname(dev), dev->si_uminor,
402 dev->si_sysref.refcnt);
409 * release a reference on a device. The device will be terminated when the
410 * last reference has been released.
412 * NOTE: we must use si_umajor to figure out the original major number,
413 * because si_ops could already be pointing at dead_dev_ops.
416 release_dev(cdev_t dev)
418 //kprintf("release_dev\n");
422 sysref_put(&dev->si_sysref);
426 devtoname(cdev_t dev)
435 if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
437 len = sizeof(dev->si_name);
438 if ((dname = dev_dname(dev)) != NULL)
439 ksnprintf(p, len, "#%s/", dname);
441 ksnprintf(p, len, "#%d/", major(dev));
445 if (mynor < 0 || mynor > 255)
446 ksnprintf(p, len, "%#x", (u_int)mynor);
448 ksnprintf(p, len, "%d", mynor);
450 return (dev->si_name);