text: /*-
   * Copyright (c) 2002 Poul-Henning Kamp
   * Copyright (c) 2002 Networks Associates Technology, Inc.
   * All rights reserved.
   *
   * This software was developed for the FreeBSD Project by Poul-Henning Kamp
   * and NAI Labs, the Security Research Division of Network Associates, Inc.
   * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
   * DARPA CHATS research program.
   *
   * 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. The names of the authors may not be used to endorse or promote
   *    products derived from this software without specific prior written
   *    permission.
   *
   * 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.
   *
   * $FreeBSD: src/sys/geom/geom_subr.c,v 1.23.2.2 2003/01/02 20:00:59 phk Exp $
   */
  
  
  #include <sys/param.h>
  #include <sys/stdint.h>
  #ifndef _KERNEL
  #include <stdio.h>
  #include <unistd.h>
  #include <stdlib.h>
  #include <signal.h>
  #include <string.h>
  #include <err.h>
  #else
  #include <sys/systm.h>
  #include <sys/kernel.h>
  #include <sys/malloc.h>
  #include <sys/bio.h>
  #include <sys/sysctl.h>
  #include <sys/proc.h>
  #include <sys/kthread.h>
  #include <sys/lock.h>
  #include <sys/mutex.h>
  #endif
  #include <sys/errno.h>
  #include <sys/sbuf.h>
  #include <geom/geom.h>
  #include <geom/geom_int.h>
  #include <machine/stdarg.h>
  
  struct class_list_head g_classes = LIST_HEAD_INITIALIZER(g_classes);
  static struct g_tailq_head geoms = TAILQ_HEAD_INITIALIZER(geoms);
  static int g_nproviders;
  char *g_wait_event, *g_wait_up, *g_wait_down, *g_wait_sim;
  
  static int g_ignition;
  
  void
  g_add_class(struct g_class *mp)
  {
  
  	if (!g_ignition) {
  		g_ignition++;
  		g_init();
  	}
  	mp->protect = 0x020016600;
  	g_topology_lock();
  	g_trace(G_T_TOPOLOGY, "g_add_class(%s)", mp->name);
  	LIST_INIT(&mp->geom);
  	LIST_INSERT_HEAD(&g_classes, mp, class);
  	if (g_nproviders > 0)
  		g_post_event(EV_NEW_CLASS, mp, NULL, NULL, NULL);
  	g_topology_unlock();
  }
  
  struct g_geom *
  g_new_geomf(struct g_class *mp, const char *fmt, ...)
  {
  	struct g_geom *gp;
  	va_list ap;
  	struct sbuf *sb;
  
  	g_topology_assert();
  	va_start(ap, fmt);
  	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
  	sbuf_vprintf(sb, fmt, ap);
  	sbuf_finish(sb);
  	gp = g_malloc(sizeof *gp, M_WAITOK | M_ZERO);
  	gp->protect = 0x020016601;
  	gp->name = g_malloc(sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
  	gp->class = mp;
  	gp->rank = 1;
  	LIST_INIT(&gp->consumer);
  	LIST_INIT(&gp->provider);
  	LIST_INSERT_HEAD(&mp->geom, gp, geom);
  	TAILQ_INSERT_HEAD(&geoms, gp, geoms);
  	strcpy(gp->name, sbuf_data(sb));
  	sbuf_delete(sb);
  	return (gp);
  }
  
  void
  g_destroy_geom(struct g_geom *gp)
  {
  
  	g_trace(G_T_TOPOLOGY, "g_destroy_geom(%p(%s))", gp, gp->name);
  	g_topology_assert();
  	KASSERT(gp->event == NULL, ("g_destroy_geom() with event"));
  	KASSERT(LIST_EMPTY(&gp->consumer),
  	    ("g_destroy_geom(%s) with consumer(s) [%p]",
  	    gp->name, LIST_FIRST(&gp->consumer)));
  	KASSERT(LIST_EMPTY(&gp->provider),
  	    ("g_destroy_geom(%s) with provider(s) [%p]",
  	    gp->name, LIST_FIRST(&gp->consumer)));
  	LIST_REMOVE(gp, geom);
  	TAILQ_REMOVE(&geoms, gp, geoms);
  	g_free(gp->name);
  	g_free(gp);
  }
  
  struct g_consumer *
  g_new_consumer(struct g_geom *gp)
  {
  	struct g_consumer *cp;
  
  	g_topology_assert();
  	KASSERT(gp->orphan != NULL,
  	    ("g_new_consumer on geom(%s) (class %s) without orphan",
  	    gp->name, gp->class->name));
  
  	cp = g_malloc(sizeof *cp, M_WAITOK | M_ZERO);
  	cp->protect = 0x020016602;
  	cp->geom = gp;
  	LIST_INSERT_HEAD(&gp->consumer, cp, consumer);
  	return(cp);
  }
  
  void
  g_destroy_consumer(struct g_consumer *cp)
  {
  
  	g_trace(G_T_TOPOLOGY, "g_destroy_consumer(%p)", cp);
  	g_topology_assert();
  	KASSERT(cp->event == NULL, ("g_destroy_consumer() with event"));
  	KASSERT (cp->provider == NULL, ("g_destroy_consumer but attached"));
  	KASSERT (cp->acr == 0, ("g_destroy_consumer with acr"));
  	KASSERT (cp->acw == 0, ("g_destroy_consumer with acw"));
  	KASSERT (cp->ace == 0, ("g_destroy_consumer with ace"));
  	LIST_REMOVE(cp, consumer);
  	g_free(cp);
  }
  
  struct g_provider *
  g_new_providerf(struct g_geom *gp, const char *fmt, ...)
  {
  	struct g_provider *pp;
  	struct sbuf *sb;
  	va_list ap;
  
  	g_topology_assert();
  	va_start(ap, fmt);
  	sb = sbuf_new(NULL, NULL, 0, SBUF_AUTOEXTEND);
  	sbuf_vprintf(sb, fmt, ap);
  	sbuf_finish(sb);
  	pp = g_malloc(sizeof *pp + sbuf_len(sb) + 1, M_WAITOK | M_ZERO);
  	pp->protect = 0x020016603;
  	pp->name = (char *)(pp + 1);
  	strcpy(pp->name, sbuf_data(sb));
  	sbuf_delete(sb);
  	LIST_INIT(&pp->consumers);
  	pp->error = ENXIO;
  	pp->geom = gp;
  	LIST_INSERT_HEAD(&gp->provider, pp, provider);
  	g_nproviders++;
  	g_post_event(EV_NEW_PROVIDER, NULL, NULL, pp, NULL);
  	return (pp);
  }
  
  void
  g_error_provider(struct g_provider *pp, int error)
  {
  
  	pp->error = error;
  }
  
  
  void
  g_destroy_provider(struct g_provider *pp)
  {
  	struct g_geom *gp;
  	struct g_consumer *cp;
  
  	g_topology_assert();
  	KASSERT(pp->event == NULL, ("g_destroy_provider() with event"));
  	KASSERT(LIST_EMPTY(&pp->consumers),
  	    ("g_destroy_provider but attached"));
  	KASSERT (pp->acr == 0, ("g_destroy_provider with acr"));
  	KASSERT (pp->acw == 0, ("g_destroy_provider with acw"));
  	KASSERT (pp->acw == 0, ("g_destroy_provider with ace"));
  	g_nproviders--;
  	LIST_REMOVE(pp, provider);
  	gp = pp->geom;
  	g_free(pp);
  	if (!(gp->flags & G_GEOM_WITHER))
  		return;
  	if (!LIST_EMPTY(&gp->provider))
  		return;
  	for (;;) {
  		cp = LIST_FIRST(&gp->consumer);
  		if (cp == NULL)
  			break;
  		g_detach(cp);
  		g_destroy_consumer(cp);
  	}
  	g_destroy_geom(gp);
  }
  
  /*
   * We keep the "geoms" list sorted by topological order (== increasing
   * numerical rank) at all times.
   * When an attach is done, the attaching geoms rank is invalidated
   * and it is moved to the tail of the list.
   * All geoms later in the sequence has their ranks reevaluated in
   * sequence.  If we cannot assign rank to a geom because it's
   * prerequisites do not have rank, we move that element to the tail
   * of the sequence with invalid rank as well.
   * At some point we encounter our original geom and if we stil fail
   * to assign it a rank, there must be a loop and we fail back to
   * g_attach() which detach again and calls redo_rank again
   * to fix up the damage.
   * It would be much simpler code wise to do it recursively, but we
   * can't risk that on the kernel stack.
   */
  
  static int
  redo_rank(struct g_geom *gp)
  {
  	struct g_consumer *cp;
  	struct g_geom *gp1, *gp2;
  	int n, m;
  
  	g_topology_assert();
  
  	/* Invalidate this geoms rank and move it to the tail */
  	gp1 = TAILQ_NEXT(gp, geoms);
  	if (gp1 != NULL) {
  		gp->rank = 0;
  		TAILQ_REMOVE(&geoms, gp, geoms);
  		TAILQ_INSERT_TAIL(&geoms, gp, geoms);
  	} else {
  		gp1 = gp;
  	}
  
  	/* re-rank the rest of the sequence */
  	for (; gp1 != NULL; gp1 = gp2) {
  		gp1->rank = 0;
  		m = 1;
  		LIST_FOREACH(cp, &gp1->consumer, consumer) {
  			if (cp->provider == NULL)
  				continue;
  			n = cp->provider->geom->rank;
  			if (n == 0) {
  				m = 0;
  				break;
  			} else if (n >= m)
  				m = n + 1;
  		}
  		gp1->rank = m;
  		gp2 = TAILQ_NEXT(gp1, geoms);
  
  		/* got a rank, moving on */
  		if (m != 0)
  			continue;
  
  		/* no rank to original geom means loop */
  		if (gp == gp1) 
  			return (ELOOP);
  
  		/* no rank, put it at the end move on */
  		TAILQ_REMOVE(&geoms, gp1, geoms);
  		TAILQ_INSERT_TAIL(&geoms, gp1, geoms);
  	}
  	return (0);
  }
  
  int
  g_attach(struct g_consumer *cp, struct g_provider *pp)
  {
  	int error;
  
  	g_topology_assert();
  	KASSERT(cp->provider == NULL, ("attach but attached"));
  	cp->provider = pp;
  	LIST_INSERT_HEAD(&pp->consumers, cp, consumers);
  	error = redo_rank(cp->geom);
  	if (error) {
  		LIST_REMOVE(cp, consumers);
  		cp->provider = NULL;
  		redo_rank(cp->geom);
  	}
  	return (error);
  }
  
  void
  g_detach(struct g_consumer *cp)
  {
  	struct g_provider *pp;
  
  	g_trace(G_T_TOPOLOGY, "g_detach(%p)", cp);
  	KASSERT(cp != (void*)0xd0d0d0d0, ("ARGH!"));
  	g_topology_assert();
  	KASSERT(cp->provider != NULL, ("detach but not attached"));
  	KASSERT(cp->acr == 0, ("detach but nonzero acr"));
  	KASSERT(cp->acw == 0, ("detach but nonzero acw"));
  	KASSERT(cp->ace == 0, ("detach but nonzero ace"));
  	KASSERT(cp->biocount == 0, ("detach but nonzero biocount"));
  	pp = cp->provider;
  	LIST_REMOVE(cp, consumers);
  	cp->provider = NULL;
  	if (LIST_EMPTY(&pp->consumers)) {
  		if (pp->geom->flags & G_GEOM_WITHER)
  			g_destroy_provider(pp);
  	}
  	redo_rank(cp->geom);
  }
  
  
  /*
   * g_access_abs()
   *
   * Access-check with absolute new values:  Just fall through
   * and use the relative version.
   */
  int
  g_access_abs(struct g_consumer *cp, int acr, int acw, int ace)
  {
  
  	g_topology_assert();
  	return(g_access_rel(cp,
  		acr - cp->acr,
  		acw - cp->acw,
  		ace - cp->ace));
  }
  
  /*
   * g_access_rel()
   *
   * Access-check with delta values.  The question asked is "can provider
   * "cp" change the access counters by the relative amounts dc[rwe] ?"
   */
  
  int
  g_access_rel(struct g_consumer *cp, int dcr, int dcw, int dce)
  {
  	struct g_provider *pp;
  	int pr,pw,pe;
  	int error;
  
  	pp = cp->provider;
  
  	g_trace(G_T_ACCESS, "g_access_rel(%p(%s), %d, %d, %d)",
  	    cp, pp->name, dcr, dcw, dce);
  
  	g_topology_assert();
  	KASSERT(cp->provider != NULL, ("access but not attached"));
  	KASSERT(cp->acr + dcr >= 0, ("access resulting in negative acr"));
  	KASSERT(cp->acw + dcw >= 0, ("access resulting in negative acw"));
  	KASSERT(cp->ace + dce >= 0, ("access resulting in negative ace"));
  	KASSERT(pp->geom->access != NULL, ("NULL geom->access"));
  
  	/*
  	 * If our class cares about being spoiled, and we have been, we
  	 * are probably just ahead of the event telling us that.  Fail
  	 * now rather than having to unravel this later.
  	 */
  	if (cp->geom->spoiled != NULL && cp->spoiled) {
  		KASSERT(dcr >= 0, ("spoiled but dcr = %d", dcr));
  		KASSERT(dcw >= 0, ("spoiled but dce = %d", dcw));
  		KASSERT(dce >= 0, ("spoiled but dcw = %d", dce));
  		KASSERT(cp->acr == 0, ("spoiled but cp->acr = %d", cp->acr));
  		KASSERT(cp->acw == 0, ("spoiled but cp->acw = %d", cp->acw));
  		KASSERT(cp->ace == 0, ("spoiled but cp->ace = %d", cp->ace));
  		return(ENXIO);
  	}
  
  	/*
  	 * Figure out what counts the provider would have had, if this
  	 * consumer had (r0w0e0) at this time.
  	 */
  	pr = pp->acr - cp->acr;
  	pw = pp->acw - cp->acw;
  	pe = pp->ace - cp->ace;
  
  	g_trace(G_T_ACCESS,
      "open delta:[r%dw%de%d] old:[r%dw%de%d] provider:[r%dw%de%d] %p(%s)",
  	    dcr, dcw, dce,
  	    cp->acr, cp->acw, cp->ace,
  	    pp->acr, pp->acw, pp->ace,
  	    pp, pp->name);
  
  	/* If we try exclusive but already write: fail */
  	if (dce > 0 && pw > 0)
  		return (EPERM);
  	/* If we try write but already exclusive: fail */
  	if (dcw > 0 && pe > 0)
  		return (EPERM);
  	/* If we try to open more but provider is error'ed: fail */
  	if ((dcr > 0 || dcw > 0 || dce > 0) && pp->error != 0)
  		return (pp->error);
  
  	/* Ok then... */
  
  	/*
  	 * If we open first write, spoil any partner consumers.
  	 * If we close last write, trigger re-taste.
  	 */
  	if (pp->acw == 0 && dcw != 0)
  		g_spoil(pp, cp);
  	else if (pp->acw != 0 && pp->acw == -dcw && 
  	    !(pp->geom->flags & G_GEOM_WITHER))
  		g_post_event(EV_NEW_PROVIDER, NULL, NULL, pp, NULL);
  
  	error = pp->geom->access(pp, dcr, dcw, dce);
  	if (!error) {
  		pp->acr += dcr;
  		pp->acw += dcw;
  		pp->ace += dce;
  		cp->acr += dcr;
  		cp->acw += dcw;
  		cp->ace += dce;
  	}
  	return (error);
  }
  
  int
  g_handleattr_int(struct bio *bp, const char *attribute, int val)
  {
  
  	return (g_handleattr(bp, attribute, &val, sizeof val));
  }
  
  int
  g_handleattr_off_t(struct bio *bp, const char *attribute, off_t val)
  {
  
  	return (g_handleattr(bp, attribute, &val, sizeof val));
  }
  
  
  int
  g_handleattr(struct bio *bp, const char *attribute, void *val, int len)
  {
  	int error;
  
  	if (strcmp(bp->bio_attribute, attribute))
  		return (0);
  	if (bp->bio_length != len) {
  		printf("bio_length %jd len %d -> EFAULT\n",
  		    (intmax_t)bp->bio_length, len);
  		error = EFAULT;
  	} else {
  		error = 0;
  		bcopy(val, bp->bio_data, len);
  		bp->bio_completed = len;
  	}
  	g_io_deliver(bp, error);
  	return (1);
  }
  
  int
  g_std_access(struct g_provider *pp __unused,
  	int dr __unused, int dw __unused, int de __unused)
  {
  
          return (0);
  }
  
  void
  g_std_done(struct bio *bp)
  {
  	struct bio *bp2;
  
  	bp2 = bp->bio_linkage;
  	if (bp2->bio_error == 0)
  		bp2->bio_error = bp->bio_error;
  	bp2->bio_completed += bp->bio_completed;
  	g_destroy_bio(bp);
  	bp2->bio_children--;	/* XXX: atomic ? */
  	if (bp2->bio_children == 0)
  		g_io_deliver(bp2, bp2->bio_error);
  }
  
  /* XXX: maybe this is only g_slice_spoiled */
  
  void
  g_std_spoiled(struct g_consumer *cp)
  {
  	struct g_geom *gp;
  	struct g_provider *pp;
  
  	g_trace(G_T_TOPOLOGY, "g_std_spoiled(%p)", cp);
  	g_topology_assert();
  	g_detach(cp);
  	gp = cp->geom;
  	LIST_FOREACH(pp, &gp->provider, provider)
  		g_orphan_provider(pp, ENXIO);
  	g_destroy_consumer(cp);
  	if (LIST_EMPTY(&gp->provider) && LIST_EMPTY(&gp->consumer))
  		g_destroy_geom(gp);
  	else
  		gp->flags |= G_GEOM_WITHER;
  }
  
  /*
   * Spoiling happens when a provider is opened for writing, but consumers
   * which are configured by in-band data are attached (slicers for instance).
   * Since the write might potentially change the in-band data, such consumers
   * need to re-evaluate their existence after the writing session closes.
   * We do this by (offering to) tear them down when the open for write happens
   * in return for a re-taste when it closes again.
   * Together with the fact that such consumers grab an 'e' bit whenever they
   * are open, regardless of mode, this ends up DTRT.
   */
  
  void
  g_spoil(struct g_provider *pp, struct g_consumer *cp)
  {
  	struct g_consumer *cp2;
  
  	g_topology_assert();
  
  	if (!strcmp(pp->name, "geom.ctl"))
  		return;
  	LIST_FOREACH(cp2, &pp->consumers, consumers) {
  		if (cp2 == cp)
  			continue;
  /*
  		KASSERT(cp2->acr == 0, ("spoiling cp->acr = %d", cp2->acr));
  		KASSERT(cp2->acw == 0, ("spoiling cp->acw = %d", cp2->acw));
  */
  		KASSERT(cp2->ace == 0, ("spoiling cp->ace = %d", cp2->ace));
  		cp2->spoiled++;
  	}
  	g_post_event(EV_SPOILED, NULL, NULL, pp, cp);
  }
  
  static struct g_class *
  g_class_by_name(const char *name)
  {
  	struct g_class *mp;
  
  	g_trace(G_T_TOPOLOGY, "g_class_by_name(%s)", name);
  	g_topology_assert();
  	LIST_FOREACH(mp, &g_classes, class)
  		if (!strcmp(mp->name, name))
  			return (mp);
  	return (NULL);
  }
  
  struct g_geom *
  g_insert_geom(const char *class, struct g_consumer *cp)
  {
  	struct g_class *mp;
  	struct g_geom *gp;
  	struct g_provider *pp, *pp2;
  	struct g_consumer *cp2;
  	int error;
  
  	g_trace(G_T_TOPOLOGY, "g_insert_geomf(%s, %p)", class, cp);
  	g_topology_assert();
  	KASSERT(cp->provider != NULL, ("g_insert_geomf but not attached"));
  	/* XXX: check for events ?? */
  	mp = g_class_by_name(class);
  	if (mp == NULL)
  		return (NULL);
  	if (mp->config == NULL)
  		return (NULL);
  	pp = cp->provider;
  	gp = mp->taste(mp, pp, G_TF_TRANSPARENT);
  	if (gp == NULL)
  		return (NULL);
  	pp2 = LIST_FIRST(&gp->provider);
  	cp2 = LIST_FIRST(&gp->consumer);
  	cp2->acr += pp->acr;
  	cp2->acw += pp->acw;
  	cp2->ace += pp->ace;
  	pp2->acr += pp->acr;
  	pp2->acw += pp->acw;
  	pp2->ace += pp->ace;
  	LIST_REMOVE(cp, consumers);
  	LIST_INSERT_HEAD(&pp2->consumers, cp, consumers);
  	cp->provider = pp2;
  	error = redo_rank(gp);
  	KASSERT(error == 0, ("redo_rank failed in g_insert_geom"));
  	return (gp);
  }
  
  int
  g_getattr__(const char *attr, struct g_consumer *cp, void *var, int len)
  {
  	int error, i;
  
  	i = len;
  	error = g_io_getattr(attr, cp, &i, var);
  	if (error)
  		return (error);
  	if (i != len)
  		return (EINVAL);
  	return (0);
  }
  
  /*
   * Check if the given pointer is a live object
   */
  
  void
  g_sanity(void *ptr)
  {
  	struct g_class *mp;
  	struct g_geom *gp;
  	struct g_consumer *cp;
  	struct g_provider *pp;
  
  	if (!(g_debugflags & 0x8))
  		return;
  	LIST_FOREACH(mp, &g_classes, class) {
  		KASSERT(mp != ptr, ("Ptr is live class"));
  		KASSERT(mp->protect == 0x20016600,
  		    ("corrupt class %p %x", mp, mp->protect));
  		LIST_FOREACH(gp, &mp->geom, geom) {
  			KASSERT(gp != ptr, ("Ptr is live geom"));
  			KASSERT(gp->protect == 0x20016601,
  			    ("corrupt geom, %p %x", gp, gp->protect));
  			KASSERT(gp->name != ptr, ("Ptr is live geom's name"));
  			LIST_FOREACH(cp, &gp->consumer, consumer) {
  				KASSERT(cp != ptr, ("Ptr is live consumer"));
  				KASSERT(cp->protect == 0x20016602,
  				    ("corrupt consumer %p %x",
  				    cp, cp->protect));
  			}
  			LIST_FOREACH(pp, &gp->provider, provider) {
  				KASSERT(pp != ptr, ("Ptr is live provider"));
  				KASSERT(pp->protect == 0x20016603,
  				    ("corrupt provider %p %x",
  				    pp, pp->protect));
  			}
  		}
  	}
  }
  
  #ifdef _KERNEL
  struct g_class *
  g_idclass(struct geomidorname *p)
  {
  	struct g_class *mp;
  	char *n;
  
  	if (p->len == 0) {
  		LIST_FOREACH(mp, &g_classes, class)
  			if ((uintptr_t)mp == p->u.id)
  				return (mp);
  		return (NULL);
  	}
  	n = g_malloc(p->len + 1, M_WAITOK);
  	if (copyin(p->u.name, n, p->len) == 0) {
  		n[p->len] = '\0';
  		LIST_FOREACH(mp, &g_classes, class)
  			if (!bcmp(n, mp->name, p->len + 1)) {
  				g_free(n);
  				return (mp);
  			}
  	}
  	g_free(n);
  	return (NULL);
  }
  
  struct g_geom *
  g_idgeom(struct geomidorname *p)
  {
  	struct g_class *mp;
  	struct g_geom *gp;
  	char *n;
  
  	if (p->len == 0) {
  		LIST_FOREACH(mp, &g_classes, class)
  			LIST_FOREACH(gp, &mp->geom, geom)
  				if ((uintptr_t)gp == p->u.id)
  					return (gp);
  		return (NULL);
  	}
  	n = g_malloc(p->len + 1, M_WAITOK);
  	if (copyin(p->u.name, n, p->len) == 0) {
  		n[p->len] = '\0';
  		LIST_FOREACH(mp, &g_classes, class)
  			LIST_FOREACH(gp, &mp->geom, geom)
  				if (!bcmp(n, gp->name, p->len + 1)) {
  					g_free(n);
  					return (gp);
  				}
  	}
  	g_free(n);
  	return (NULL);
  }
  
  struct g_provider *
  g_idprovider(struct geomidorname *p)
  {
  	struct g_class *mp;
  	struct g_geom *gp;
  	struct g_provider *pp;
  	char *n;
  
  	if (p->len == 0) {
  		LIST_FOREACH(mp, &g_classes, class)
  			LIST_FOREACH(gp, &mp->geom, geom)
  				LIST_FOREACH(pp, &gp->provider, provider)
  					if ((uintptr_t)pp == p->u.id)
  						return (pp);
  		return (NULL);
  	}
  	n = g_malloc(p->len + 1, M_WAITOK);
  	if (copyin(p->u.name, n, p->len) == 0) {
  		n[p->len] = '\0';
  		LIST_FOREACH(mp, &g_classes, class)
  			LIST_FOREACH(gp, &mp->geom, geom)
  				LIST_FOREACH(pp, &gp->provider, provider)
  					if (!bcmp(n, pp->name, p->len + 1)) {
  						g_free(n);
  						return (pp);
  					}
  	}
  	g_free(n);
  	return (NULL);
  }
  #endif /* _KERNEL */
  