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kern_conf.c
506 lines (434 loc) · 11.8 KB
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kern_conf.c
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/*-
* Parts Copyright (c) 1995 Terrence R. Lambert
* Copyright (c) 1995 Julian R. Elischer
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by Terrence R. Lambert.
* 4. The name Terrence R. Lambert may not be used to endorse or promote
* products derived from this software without specific prior written
* permission.
*
* THIS SOFTWARE IS PROVIDED BY Julian R. Elischer ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE TERRENCE R. LAMBERT BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* $FreeBSD: src/sys/kern/kern_conf.c,v 1.73.2.3 2003/03/10 02:18:25 imp Exp $
* $DragonFly: src/sys/kern/kern_conf.c,v 1.23 2007/05/09 00:53:34 dillon Exp $
*/
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/sysctl.h>
#include <sys/systm.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/queue.h>
#include <sys/device.h>
#include <sys/disk.h>
#include <machine/stdarg.h>
#include <sys/sysref2.h>
#include <sys/devfs.h>
MALLOC_DEFINE(M_DEVT, "cdev_t", "dev_t storage");
int dev_ref_debug = 0;
SYSCTL_INT(_debug, OID_AUTO, dev_refs, CTLFLAG_RW, &dev_ref_debug, 0,
"Toggle device reference debug output");
/*
* cdev_t and u_dev_t primitives. Note that the major number is always
* extracted from si_umajor, not from si_devsw, because si_devsw is replaced
* when a device is destroyed.
*/
int
major(cdev_t dev)
{
if (dev == NULL)
return NOUDEV;
return(dev->si_umajor);
}
int
minor(cdev_t dev)
{
if (dev == NULL)
return NOUDEV;
return(dev->si_uminor);
}
/*
* Compatibility function with old udev_t format to convert the
* non-consecutive minor space into a consecutive minor space.
*/
int
lminor(cdev_t dev)
{
int y;
if (dev == NULL)
return NOUDEV;
y = dev->si_uminor;
if (y & 0x0000ff00)
return NOUDEV;
return ((y & 0xff) | (y >> 8));
}
/*
* Convert a device pointer to an old style device number. Return NOUDEV
* if the device is invalid or if the device (maj,min) cannot be converted
* to an old style udev_t.
*/
udev_t
dev2udev(cdev_t dev)
{
if (dev == NULL)
return NOUDEV;
return (udev_t)dev->si_inode;
}
/*
* Convert a device number to a device pointer. The device is referenced
* ad-hoc, meaning that the caller should call reference_dev() if it wishes
* to keep ahold of the returned structure long term.
*
* The returned device is associated with the currently installed cdevsw
* for the requested major number. NULL is returned if the major number
* has not been registered.
*/
cdev_t
udev2dev(udev_t x, int b)
{
if (x == NOUDEV || b != 0)
return(NULL);
return devfs_find_device_by_udev(x);
}
int
dev_is_good(cdev_t dev)
{
if (dev != NULL && dev->si_ops != &dead_dev_ops)
return(1);
return(0);
}
/*
* Various user device number extraction and conversion routines
*/
int
uminor(udev_t dev)
{
if (dev == NOUDEV)
return(-1);
return(dev & 0xffff00ff);
}
int
umajor(udev_t dev)
{
if (dev == NOUDEV)
return(-1);
return((dev & 0xff00) >> 8);
}
udev_t
makeudev(int x, int y)
{
if ((x & 0xffffff00) || (y & 0x0000ff00))
return NOUDEV;
return ((x << 8) | y);
}
/*
* Create an internal or external device.
*
* This routine creates and returns an unreferenced ad-hoc entry for the
* device which will remain intact until the device is destroyed. If the
* caller intends to store the device pointer it must call reference_dev()
* to retain a real reference to the device.
*
* If an entry already exists, this function will set (or override)
* its cred requirements and name (XXX DEVFS interface).
*/
cdev_t
make_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
int perms, const char *fmt, ...)
{
cdev_t devfs_dev;
__va_list ap;
/*
* compile the cdevsw and install the device
*/
compile_dev_ops(ops);
devfs_dev = devfs_new_cdev(ops, minor, NULL);
__va_start(ap, fmt);
kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
32, fmt, ap);
__va_end(ap);
devfs_debug(DEVFS_DEBUG_INFO,
"make_dev called for %s\n",
devfs_dev->si_name);
devfs_create_dev(devfs_dev, uid, gid, perms);
return (devfs_dev);
}
/*
* make_dev_covering has equivalent functionality to make_dev, except that it
* also takes the cdev of the underlying device. Hence this function should
* only be used by systems and drivers which create devices covering others
*/
cdev_t
make_dev_covering(struct dev_ops *ops, struct dev_ops *bops, int minor,
uid_t uid, gid_t gid, int perms, const char *fmt, ...)
{
cdev_t devfs_dev;
__va_list ap;
/*
* compile the cdevsw and install the device
*/
compile_dev_ops(ops);
devfs_dev = devfs_new_cdev(ops, minor, bops);
__va_start(ap, fmt);
kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
32, fmt, ap);
__va_end(ap);
devfs_debug(DEVFS_DEBUG_INFO,
"make_dev called for %s\n",
devfs_dev->si_name);
devfs_create_dev(devfs_dev, uid, gid, perms);
return (devfs_dev);
}
cdev_t
make_only_devfs_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
int perms, const char *fmt, ...)
{
cdev_t devfs_dev;
__va_list ap;
/*
* compile the cdevsw and install the device
*/
compile_dev_ops(ops);
devfs_dev = devfs_new_cdev(ops, minor, NULL);
/*
* Set additional fields (XXX DEVFS interface goes here)
*/
__va_start(ap, fmt);
kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
32, fmt, ap);
__va_end(ap);
devfs_create_dev(devfs_dev, uid, gid, perms);
return (devfs_dev);
}
cdev_t
make_only_dev(struct dev_ops *ops, int minor, uid_t uid, gid_t gid,
int perms, const char *fmt, ...)
{
cdev_t devfs_dev;
__va_list ap;
/*
* compile the cdevsw and install the device
*/
compile_dev_ops(ops);
devfs_dev = devfs_new_cdev(ops, minor, NULL);
devfs_dev->si_perms = perms;
devfs_dev->si_uid = uid;
devfs_dev->si_gid = gid;
/*
* Set additional fields (XXX DEVFS interface goes here)
*/
__va_start(ap, fmt);
kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
32, fmt, ap);
__va_end(ap);
reference_dev(devfs_dev);
return (devfs_dev);
}
cdev_t
make_only_dev_covering(struct dev_ops *ops, struct dev_ops *bops, int minor,
uid_t uid, gid_t gid, int perms, const char *fmt, ...)
{
cdev_t devfs_dev;
__va_list ap;
/*
* compile the cdevsw and install the device
*/
compile_dev_ops(ops);
devfs_dev = devfs_new_cdev(ops, minor, bops);
devfs_dev->si_perms = perms;
devfs_dev->si_uid = uid;
devfs_dev->si_gid = gid;
/*
* Set additional fields (XXX DEVFS interface goes here)
*/
__va_start(ap, fmt);
kvsnrprintf(devfs_dev->si_name, sizeof(devfs_dev->si_name),
32, fmt, ap);
__va_end(ap);
reference_dev(devfs_dev);
return (devfs_dev);
}
void
destroy_only_dev(cdev_t dev)
{
release_dev(dev);
release_dev(dev);
release_dev(dev);
}
/*
* destroy_dev() removes the adhoc association for a device and revectors
* its ops to &dead_dev_ops.
*
* This routine releases the reference count associated with the ADHOC
* entry, plus releases the reference count held by the caller. What this
* means is that you should not call destroy_dev(make_dev(...)), because
* make_dev() does not bump the reference count (beyond what it needs to
* create the ad-hoc association). Any procedure that intends to destroy
* a device must have its own reference to it first.
*/
void
destroy_dev(cdev_t dev)
{
if (dev) {
devfs_debug(DEVFS_DEBUG_DEBUG,
"destroy_dev called for %s\n",
dev->si_name);
devfs_destroy_dev(dev);
}
}
/*
* Make sure all asynchronous disk and devfs related operations have
* completed.
*
* Typically called prior to mountroot to ensure that all disks have
* been completely probed and on module unload to ensure that ops
* structures have been dereferenced.
*/
void
sync_devs(void)
{
disk_config(NULL);
devfs_config();
disk_config(NULL);
devfs_config();
}
int
make_dev_alias(cdev_t target, const char *fmt, ...)
{
__va_list ap;
char *name;
__va_start(ap, fmt);
kvasnrprintf(&name, PATH_MAX, 32, fmt, ap);
__va_end(ap);
devfs_make_alias(name, target);
kvasfree(&name);
return 0;
}
int
destroy_dev_alias(cdev_t target, const char *fmt, ...)
{
__va_list ap;
char *name;
__va_start(ap, fmt);
kvasnrprintf(&name, PATH_MAX, 32, fmt, ap);
__va_end(ap);
devfs_destroy_alias(name, target);
kvasfree(&name);
return 0;
}
extern struct dev_ops default_dev_ops;
cdev_t
make_autoclone_dev(struct dev_ops *ops, struct devfs_bitmap *bitmap,
d_clone_t *nhandler, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
{
__va_list ap;
cdev_t dev;
char *name;
__va_start(ap, fmt);
kvasnrprintf(&name, PATH_MAX, 32, fmt, ap);
__va_end(ap);
if (bitmap != NULL)
devfs_clone_bitmap_init(bitmap);
devfs_clone_handler_add(name, nhandler);
dev = make_dev_covering(&default_dev_ops, ops, 0xffff00ff,
uid, gid, perms, "%s", name);
kvasfree(&name);
return dev;
}
void
destroy_autoclone_dev(cdev_t dev, struct devfs_bitmap *bitmap)
{
if (dev == NULL)
return;
devfs_clone_handler_del(dev->si_name);
if (bitmap != NULL)
devfs_clone_bitmap_uninit(bitmap);
destroy_dev(dev);
}
/*
* Add a reference to a device. Callers generally add their own references
* when they are going to store a device node in a variable for long periods
* of time, to prevent a disassociation from free()ing the node.
*
* Also note that a caller that intends to call destroy_dev() must first
* obtain a reference on the device. The ad-hoc reference you get with
* make_dev() and friends is NOT sufficient to be able to call destroy_dev().
*/
cdev_t
reference_dev(cdev_t dev)
{
//kprintf("reference_dev\n");
if (dev != NULL) {
sysref_get(&dev->si_sysref);
if (dev_ref_debug & 2) {
kprintf("reference dev %p %s(minor=%08x) refs=%d\n",
dev, devtoname(dev), dev->si_uminor,
dev->si_sysref.refcnt);
}
}
return(dev);
}
/*
* release a reference on a device. The device will be terminated when the
* last reference has been released.
*
* NOTE: we must use si_umajor to figure out the original major number,
* because si_ops could already be pointing at dead_dev_ops.
*/
void
release_dev(cdev_t dev)
{
//kprintf("release_dev\n");
if (dev == NULL)
return;
sysref_put(&dev->si_sysref);
}
const char *
devtoname(cdev_t dev)
{
int mynor;
int len;
char *p;
const char *dname;
if (dev == NULL)
return("#nodev");
if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
p = dev->si_name;
len = sizeof(dev->si_name);
if ((dname = dev_dname(dev)) != NULL)
ksnprintf(p, len, "#%s/", dname);
else
ksnprintf(p, len, "#%d/", major(dev));
len -= strlen(p);
p += strlen(p);
mynor = minor(dev);
if (mynor < 0 || mynor > 255)
ksnprintf(p, len, "%#x", (u_int)mynor);
else
ksnprintf(p, len, "%d", mynor);
}
return (dev->si_name);
}