FreeBSD-5.3/sys/kern/kern_conf.c
/*-
* Copyright (c) 1999-2002 Poul-Henning Kamp
* 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.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``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 AUTHOR OR CONTRIBUTORS 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD: src/sys/kern/kern_conf.c,v 1.155 2004/08/15 06:24:40 jmg Exp $");
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/bio.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/sysctl.h>
#include <sys/module.h>
#include <sys/malloc.h>
#include <sys/conf.h>
#include <sys/vnode.h>
#include <sys/queue.h>
#include <sys/poll.h>
#include <sys/ctype.h>
#include <sys/tty.h>
#include <machine/stdarg.h>
static MALLOC_DEFINE(M_DEVT, "cdev", "cdev storage");
/* Built at compile time from sys/conf/majors */
extern unsigned char reserved_majors[256];
/*
* This is the number of hash-buckets. Experiments with 'real-life'
* dev_t's show that a prime halfway between two powers of two works
* best.
*/
#define DEVT_HASH 83
/* The number of struct cdev *'s we can create before malloc(9) kick in. */
#define DEVT_STASH 50
static struct cdev devt_stash[DEVT_STASH];
static LIST_HEAD(, cdev) dev_hash[DEVT_HASH];
static LIST_HEAD(, cdev) dev_free;
static int free_devt;
SYSCTL_INT(_debug, OID_AUTO, free_devt, CTLFLAG_RW, &free_devt, 0, "");
static struct mtx devmtx;
static void freedev(struct cdev *dev);
static struct cdev *newdev(int x, int y);
static void
devlock(void)
{
if (!mtx_initialized(&devmtx))
mtx_init(&devmtx, "cdev", NULL, MTX_DEF);
mtx_lock(&devmtx);
}
static void
devunlock(void)
{
mtx_unlock(&devmtx);
}
void
dev_ref(struct cdev *dev)
{
devlock();
dev->si_refcount++;
devunlock();
}
void
dev_rel(struct cdev *dev)
{
devlock();
dev->si_refcount--;
KASSERT(dev->si_refcount >= 0,
("dev_rel(%s) gave negative count", devtoname(dev)));
if (dev->si_devsw == NULL && dev->si_refcount == 0) {
LIST_REMOVE(dev, si_list);
freedev(dev);
}
devunlock();
}
void
cdevsw_ref(struct cdevsw *csw)
{
devlock();
csw->d_refcount++;
devunlock();
}
void
cdevsw_rel(struct cdevsw *csw)
{
devlock();
csw->d_refcount--;
KASSERT(csw->d_refcount >= 0,
("cdevsw_vrel(%s) gave negative count", csw->d_name));
devunlock();
}
int
nullop(void)
{
return (0);
}
int
eopnotsupp(void)
{
return (EOPNOTSUPP);
}
static int
enxio(void)
{
return (ENXIO);
}
static int
enodev(void)
{
return (ENODEV);
}
/* Define a dead_cdevsw for use when devices leave unexpectedly. */
#define dead_open (d_open_t *)enxio
#define dead_close (d_close_t *)enxio
#define dead_read (d_read_t *)enxio
#define dead_write (d_write_t *)enxio
#define dead_ioctl (d_ioctl_t *)enxio
#define dead_poll (d_poll_t *)enodev
#define dead_mmap (d_mmap_t *)enodev
static void
dead_strategy(struct bio *bp)
{
biofinish(bp, NULL, ENXIO);
}
#define dead_dump (dumper_t *)enxio
#define dead_kqfilter (d_kqfilter_t *)enxio
static struct cdevsw dead_cdevsw = {
.d_version = D_VERSION,
.d_flags = D_NEEDGIANT, /* XXX: does dead_strategy need this ? */
.d_open = dead_open,
.d_close = dead_close,
.d_read = dead_read,
.d_write = dead_write,
.d_ioctl = dead_ioctl,
.d_poll = dead_poll,
.d_mmap = dead_mmap,
.d_strategy = dead_strategy,
.d_name = "dead",
.d_maj = 255,
.d_dump = dead_dump,
.d_kqfilter = dead_kqfilter
};
/* Default methods if driver does not specify method */
#define null_open (d_open_t *)nullop
#define null_close (d_close_t *)nullop
#define no_read (d_read_t *)enodev
#define no_write (d_write_t *)enodev
#define no_ioctl (d_ioctl_t *)enodev
#define no_mmap (d_mmap_t *)enodev
#define no_kqfilter (d_kqfilter_t *)enodev
static void
no_strategy(struct bio *bp)
{
biofinish(bp, NULL, ENODEV);
}
static int
no_poll(struct cdev *dev __unused, int events, struct thread *td __unused)
{
/*
* Return true for read/write. If the user asked for something
* special, return POLLNVAL, so that clients have a way of
* determining reliably whether or not the extended
* functionality is present without hard-coding knowledge
* of specific filesystem implementations.
* Stay in sync with vop_nopoll().
*/
if (events & ~POLLSTANDARD)
return (POLLNVAL);
return (events & (POLLIN | POLLOUT | POLLRDNORM | POLLWRNORM));
}
#define no_dump (dumper_t *)enodev
struct cdevsw *
devsw(struct cdev *dev)
{
if (dev->si_devsw != NULL)
return (dev->si_devsw);
return (&dead_cdevsw);
}
/*
* struct cdev * and u_dev_t primitives
*/
int
major(struct cdev *x)
{
if (x == NULL)
return NODEV;
return((x->si_udev >> 8) & 0xff);
}
int
minor(struct cdev *x)
{
if (x == NULL)
return NODEV;
return(x->si_udev & 0xffff00ff);
}
int
dev2unit(struct cdev *x)
{
int i;
if (x == NULL)
return NODEV;
i = minor(x);
return ((i & 0xff) | (i >> 8));
}
int
unit2minor(int unit)
{
KASSERT(unit <= 0xffffff, ("Invalid unit (%d) in unit2minor", unit));
return ((unit & 0xff) | ((unit << 8) & ~0xffff));
}
static struct cdev *
allocdev(void)
{
static int stashed;
struct cdev *si;
if (LIST_FIRST(&dev_free)) {
si = LIST_FIRST(&dev_free);
LIST_REMOVE(si, si_hash);
} else if (stashed >= DEVT_STASH) {
MALLOC(si, struct cdev *, sizeof(*si), M_DEVT,
M_USE_RESERVE | M_ZERO | M_WAITOK);
} else {
si = devt_stash + stashed++;
bzero(si, sizeof *si);
si->si_flags |= SI_STASHED;
}
si->__si_namebuf[0] = '\0';
si->si_name = si->__si_namebuf;
LIST_INIT(&si->si_children);
TAILQ_INIT(&si->si_snapshots);
return (si);
}
static struct cdev *
newdev(int x, int y)
{
struct cdev *si;
dev_t udev;
int hash;
if (x == umajor(NODEV) && y == uminor(NODEV))
panic("newdev of NODEV");
udev = (x << 8) | y;
hash = udev % DEVT_HASH;
LIST_FOREACH(si, &dev_hash[hash], si_hash) {
if (si->si_udev == udev)
return (si);
}
si = allocdev();
si->si_udev = udev;
LIST_INSERT_HEAD(&dev_hash[hash], si, si_hash);
return (si);
}
static void
freedev(struct cdev *dev)
{
if (dev->si_flags & SI_STASHED) {
bzero(dev, sizeof(*dev));
dev->si_flags |= SI_STASHED;
LIST_INSERT_HEAD(&dev_free, dev, si_hash);
} else {
FREE(dev, M_DEVT);
}
}
dev_t
dev2udev(struct cdev *x)
{
if (x == NULL)
return (NODEV);
return (x->si_udev);
}
struct cdev *
findcdev(dev_t udev)
{
struct cdev *si;
int hash;
if (udev == NODEV)
return (NULL);
hash = udev % DEVT_HASH;
LIST_FOREACH(si, &dev_hash[hash], si_hash) {
if (si->si_udev == udev)
return (si);
}
return (NULL);
}
int
uminor(dev_t dev)
{
return (dev & 0xffff00ff);
}
int
umajor(dev_t dev)
{
return ((dev & 0xff00) >> 8);
}
static void
find_major(struct cdevsw *devsw)
{
int i;
for (i = NUMCDEVSW - 1; i > 0; i--)
if (reserved_majors[i] != i)
break;
KASSERT(i > 0, ("Out of major numbers (%s)", devsw->d_name));
devsw->d_maj = i;
reserved_majors[i] = i;
devsw->d_flags |= D_ALLOCMAJ;
}
static void
fini_cdevsw(struct cdevsw *devsw)
{
if (devsw->d_flags & D_ALLOCMAJ) {
reserved_majors[devsw->d_maj] = 0;
devsw->d_maj = MAJOR_AUTO;
devsw->d_flags &= ~D_ALLOCMAJ;
} else if (devsw->d_maj == 0)
devsw->d_maj = 256;
devsw->d_flags &= ~D_INIT;
}
static void
prep_cdevsw(struct cdevsw *devsw)
{
devlock();
if (devsw->d_version != D_VERSION_00) {
printf(
"WARNING: Device driver \"%s\" has wrong version %s\n",
devsw->d_name, "and is disabled. Recompile KLD module.");
devsw->d_open = dead_open;
devsw->d_close = dead_close;
devsw->d_read = dead_read;
devsw->d_write = dead_write;
devsw->d_ioctl = dead_ioctl;
devsw->d_poll = dead_poll;
devsw->d_mmap = dead_mmap;
devsw->d_strategy = dead_strategy;
devsw->d_dump = dead_dump;
devsw->d_kqfilter = dead_kqfilter;
}
if (devsw->d_flags & D_TTY) {
if (devsw->d_ioctl == NULL) devsw->d_ioctl = ttyioctl;
if (devsw->d_read == NULL) devsw->d_read = ttyread;
if (devsw->d_write == NULL) devsw->d_write = ttywrite;
if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = ttykqfilter;
if (devsw->d_poll == NULL) devsw->d_poll = ttypoll;
}
if (devsw->d_open == NULL) devsw->d_open = null_open;
if (devsw->d_close == NULL) devsw->d_close = null_close;
if (devsw->d_read == NULL) devsw->d_read = no_read;
if (devsw->d_write == NULL) devsw->d_write = no_write;
if (devsw->d_ioctl == NULL) devsw->d_ioctl = no_ioctl;
if (devsw->d_poll == NULL) devsw->d_poll = no_poll;
if (devsw->d_mmap == NULL) devsw->d_mmap = no_mmap;
if (devsw->d_strategy == NULL) devsw->d_strategy = no_strategy;
if (devsw->d_dump == NULL) devsw->d_dump = no_dump;
if (devsw->d_kqfilter == NULL) devsw->d_kqfilter = no_kqfilter;
LIST_INIT(&devsw->d_devs);
devsw->d_flags |= D_INIT;
if (devsw->d_maj == MAJOR_AUTO) {
find_major(devsw);
} else {
if (devsw->d_maj == 256) /* XXX: tty_cons.c is magic */
devsw->d_maj = 0;
KASSERT(devsw->d_maj >= 0 && devsw->d_maj < 256,
("Invalid major (%d) in make_dev", devsw->d_maj));
if (reserved_majors[devsw->d_maj] != devsw->d_maj) {
printf("WARNING: driver \"%s\" used %s %d\n",
devsw->d_name, "unreserved major device number",
devsw->d_maj);
reserved_majors[devsw->d_maj] = devsw->d_maj;
}
}
devunlock();
}
struct cdev *
make_dev(struct cdevsw *devsw, int minornr, uid_t uid, gid_t gid, int perms, const char *fmt, ...)
{
struct cdev *dev;
va_list ap;
int i;
KASSERT((minornr & ~0xffff00ff) == 0,
("Invalid minor (0x%x) in make_dev", minornr));
if (!(devsw->d_flags & D_INIT))
prep_cdevsw(devsw);
dev = newdev(devsw->d_maj, minornr);
if (dev->si_flags & SI_CHEAPCLONE &&
dev->si_flags & SI_NAMED &&
dev->si_devsw == devsw) {
/*
* This is allowed as it removes races and generally
* simplifies cloning devices.
* XXX: still ??
*/
return (dev);
}
devlock();
KASSERT(!(dev->si_flags & SI_NAMED),
("make_dev() by driver %s on pre-existing device (maj=%d, min=%d, name=%s)",
devsw->d_name, major(dev), minor(dev), devtoname(dev)));
va_start(ap, fmt);
i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
if (i > (sizeof dev->__si_namebuf - 1)) {
printf("WARNING: Device name truncated! (%s)",
dev->__si_namebuf);
}
va_end(ap);
dev->si_devsw = devsw;
dev->si_uid = uid;
dev->si_gid = gid;
dev->si_mode = perms;
dev->si_flags |= SI_NAMED;
LIST_INSERT_HEAD(&devsw->d_devs, dev, si_list);
devfs_create(dev);
devunlock();
return (dev);
}
int
dev_named(struct cdev *pdev, const char *name)
{
struct cdev *cdev;
if (strcmp(devtoname(pdev), name) == 0)
return (1);
LIST_FOREACH(cdev, &pdev->si_children, si_siblings)
if (strcmp(devtoname(cdev), name) == 0)
return (1);
return (0);
}
void
dev_depends(struct cdev *pdev, struct cdev *cdev)
{
devlock();
cdev->si_parent = pdev;
cdev->si_flags |= SI_CHILD;
LIST_INSERT_HEAD(&pdev->si_children, cdev, si_siblings);
devunlock();
}
struct cdev *
make_dev_alias(struct cdev *pdev, const char *fmt, ...)
{
struct cdev *dev;
va_list ap;
int i;
dev = allocdev();
devlock();
dev->si_flags |= SI_ALIAS;
dev->si_flags |= SI_NAMED;
va_start(ap, fmt);
i = vsnrprintf(dev->__si_namebuf, sizeof dev->__si_namebuf, 32, fmt, ap);
if (i > (sizeof dev->__si_namebuf - 1)) {
printf("WARNING: Device name truncated! (%s)",
dev->__si_namebuf);
}
va_end(ap);
devfs_create(dev);
devunlock();
dev_depends(pdev, dev);
return (dev);
}
static void
idestroy_dev(struct cdev *dev)
{
if (!(dev->si_flags & SI_NAMED)) {
printf( "WARNING: Driver mistake: destroy_dev on %d/%d\n",
major(dev), minor(dev));
panic("don't do that");
}
devfs_destroy(dev);
/* Remove name marking */
dev->si_flags &= ~SI_NAMED;
/* If we are a child, remove us from the parents list */
if (dev->si_flags & SI_CHILD) {
LIST_REMOVE(dev, si_siblings);
dev->si_flags &= ~SI_CHILD;
}
/* Kill our children */
while (!LIST_EMPTY(&dev->si_children))
idestroy_dev(LIST_FIRST(&dev->si_children));
/* Remove from clone list */
if (dev->si_flags & SI_CLONELIST) {
LIST_REMOVE(dev, si_clone);
dev->si_flags &= ~SI_CLONELIST;
}
if (!(dev->si_flags & SI_ALIAS)) {
/* Remove from cdevsw list */
LIST_REMOVE(dev, si_list);
/* If cdevsw has no struct cdev *'s, clean it */
if (LIST_EMPTY(&dev->si_devsw->d_devs))
fini_cdevsw(dev->si_devsw);
LIST_REMOVE(dev, si_hash);
}
dev->si_drv1 = 0;
dev->si_drv2 = 0;
dev->si_devsw = NULL;
bzero(&dev->__si_u, sizeof(dev->__si_u));
dev->si_flags &= ~SI_ALIAS;
if (dev->si_refcount > 0) {
LIST_INSERT_HEAD(&dead_cdevsw.d_devs, dev, si_list);
} else {
freedev(dev);
}
}
void
destroy_dev(struct cdev *dev)
{
devlock();
idestroy_dev(dev);
devunlock();
}
const char *
devtoname(struct cdev *dev)
{
char *p;
int mynor;
if (dev->si_name[0] == '#' || dev->si_name[0] == '\0') {
p = dev->si_name;
if (devsw(dev))
sprintf(p, "#%s/", devsw(dev)->d_name);
else
sprintf(p, "#%d/", major(dev));
p += strlen(p);
mynor = minor(dev);
if (mynor < 0 || mynor > 255)
sprintf(p, "%#x", (u_int)mynor);
else
sprintf(p, "%d", mynor);
}
return (dev->si_name);
}
int
dev_stdclone(char *name, char **namep, const char *stem, int *unit)
{
int u, i;
i = strlen(stem);
if (bcmp(stem, name, i) != 0)
return (0);
if (!isdigit(name[i]))
return (0);
u = 0;
if (name[i] == '0' && isdigit(name[i+1]))
return (0);
while (isdigit(name[i])) {
u *= 10;
u += name[i++] - '0';
}
if (u > 0xffffff)
return (0);
*unit = u;
if (namep)
*namep = &name[i];
if (name[i])
return (2);
return (1);
}
/*
* Helper functions for cloning device drivers.
*
* The objective here is to make it unnecessary for the device drivers to
* use rman or similar to manage their unit number space. Due to the way
* we do "on-demand" devices, using rman or other "private" methods
* will be very tricky to lock down properly once we lock down this file.
*
* Instead we give the drivers these routines which puts the struct cdev *'s
* that are to be managed on their own list, and gives the driver the ability
* to ask for the first free unit number or a given specified unit number.
*
* In addition these routines support paired devices (pty, nmdm and similar)
* by respecting a number of "flag" bits in the minor number.
*
*/
struct clonedevs {
LIST_HEAD(,cdev) head;
};
void
clone_setup(struct clonedevs **cdp)
{
*cdp = malloc(sizeof **cdp, M_DEVBUF, M_WAITOK | M_ZERO);
LIST_INIT(&(*cdp)->head);
}
int
clone_create(struct clonedevs **cdp, struct cdevsw *csw, int *up, struct cdev **dp, u_int extra)
{
struct clonedevs *cd;
struct cdev *dev, *dl, *de;
int unit, low, u;
KASSERT(*cdp != NULL,
("clone_setup() not called in driver \"%s\"", csw->d_name));
KASSERT(!(extra & CLONE_UNITMASK),
("Illegal extra bits (0x%x) in clone_create", extra));
KASSERT(*up <= CLONE_UNITMASK,
("Too high unit (0x%x) in clone_create", *up));
if (csw->d_maj == MAJOR_AUTO)
find_major(csw);
/*
* Search the list for a lot of things in one go:
* A preexisting match is returned immediately.
* The lowest free unit number if we are passed -1, and the place
* in the list where we should insert that new element.
* The place to insert a specified unit number, if applicable
* the end of the list.
*/
unit = *up;
low = extra;
de = dl = NULL;
cd = *cdp;
LIST_FOREACH(dev, &cd->head, si_clone) {
u = dev2unit(dev);
if (u == (unit | extra)) {
*dp = dev;
return (0);
}
if (unit == -1 && u == low) {
low++;
de = dev;
continue;
}
if (u > (unit | extra)) {
dl = dev;
break;
}
de = dev;
}
if (unit == -1)
unit = low & CLONE_UNITMASK;
dev = newdev(csw->d_maj, unit2minor(unit | extra));
KASSERT(!(dev->si_flags & SI_CLONELIST),
("Dev %p should not be on clonelist", dev));
if (dl != NULL)
LIST_INSERT_BEFORE(dl, dev, si_clone);
else if (de != NULL)
LIST_INSERT_AFTER(de, dev, si_clone);
else
LIST_INSERT_HEAD(&cd->head, dev, si_clone);
dev->si_flags |= SI_CLONELIST;
*up = unit;
return (1);
}
/*
* Kill everything still on the list. The driver should already have
* disposed of any softc hung of the struct cdev *'s at this time.
*/
void
clone_cleanup(struct clonedevs **cdp)
{
struct cdev *dev, *tdev;
struct clonedevs *cd;
cd = *cdp;
if (cd == NULL)
return;
LIST_FOREACH_SAFE(dev, &cd->head, si_clone, tdev) {
KASSERT(dev->si_flags & SI_NAMED,
("Driver has goofed in cloning underways udev %x", dev->si_udev));
destroy_dev(dev);
}
free(cd, M_DEVBUF);
*cdp = NULL;
}
/*
* Helper sysctl for devname(3). We're given a struct cdev * and return
* the name, if any, registered by the device driver.
*/
static int
sysctl_devname(SYSCTL_HANDLER_ARGS)
{
int error;
dev_t ud;
struct cdev *dev;
error = SYSCTL_IN(req, &ud, sizeof (ud));
if (error)
return (error);
if (ud == NODEV)
return(EINVAL);
dev = findcdev(ud);
if (dev == NULL)
error = ENOENT;
else
error = SYSCTL_OUT(req, dev->si_name, strlen(dev->si_name) + 1);
return (error);
}
SYSCTL_PROC(_kern, OID_AUTO, devname, CTLTYPE_OPAQUE|CTLFLAG_RW|CTLFLAG_ANYBODY,
NULL, 0, sysctl_devname, "", "devname(3) handler");