The Design and Implementation of the FreeBSD Operating System, Second Edition
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FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_bsd.c

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    1 /*-
    2  * Copyright (c) 2002 Poul-Henning Kamp
    3  * Copyright (c) 2002 Networks Associates Technology, Inc.
    4  * All rights reserved.
    5  *
    6  * This software was developed for the FreeBSD Project by Poul-Henning Kamp
    7  * and NAI Labs, the Security Research Division of Network Associates, Inc.
    8  * under DARPA/SPAWAR contract N66001-01-C-8035 ("CBOSS"), as part of the
    9  * DARPA CHATS research program.
   10  *
   11  * Redistribution and use in source and binary forms, with or without
   12  * modification, are permitted provided that the following conditions
   13  * are met:
   14  * 1. Redistributions of source code must retain the above copyright
   15  *    notice, this list of conditions and the following disclaimer.
   16  * 2. Redistributions in binary form must reproduce the above copyright
   17  *    notice, this list of conditions and the following disclaimer in the
   18  *    documentation and/or other materials provided with the distribution.
   19  * 3. The names of the authors may not be used to endorse or promote
   20  *    products derived from this software without specific prior written
   21  *    permission.
   22  *
   23  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   33  * SUCH DAMAGE.
   34  *
   35  * This is the method for dealing with BSD disklabels.  It has been
   36  * extensively (by my standards at least) commented, in the vain hope that
   37  * it will serve as the source in future copy&paste operations.
   38  */
   39 
   40 #include <sys/cdefs.h>
   41 __FBSDID("$FreeBSD: releng/5.2/sys/geom/geom_bsd.c 119660 2003-09-01 20:45:32Z phk $");
   42 
   43 #include <sys/param.h>
   44 #include <sys/endian.h>
   45 #include <sys/systm.h>
   46 #include <sys/kernel.h>
   47 #include <sys/conf.h>
   48 #include <sys/bio.h>
   49 #include <sys/malloc.h>
   50 #include <sys/lock.h>
   51 #include <sys/mutex.h>
   52 #include <sys/md5.h>
   53 #include <sys/errno.h>
   54 #include <sys/disklabel.h>
   55 #include <geom/geom.h>
   56 #include <geom/geom_slice.h>
   57 
   58 #define BSD_CLASS_NAME "BSD"
   59 
   60 #define ALPHA_LABEL_OFFSET      64
   61 
   62 #define LABELSIZE (148 + 16 * MAXPARTITIONS)
   63 
   64 static void g_bsd_hotwrite(void *arg, int flag);
   65 /*
   66  * Our private data about one instance.  All the rest is handled by the
   67  * slice code and stored in its softc, so this is just the stuff
   68  * specific to BSD disklabels.
   69  */
   70 struct g_bsd_softc {
   71         off_t   labeloffset;
   72         off_t   mbroffset;
   73         off_t   rawoffset;
   74         struct disklabel ondisk;
   75         u_char  label[LABELSIZE];
   76         u_char  labelsum[16];
   77 };
   78 
   79 /*
   80  * Modify our slicer to match proposed disklabel, if possible.
   81  * This is where we make sure we don't do something stupid.
   82  */
   83 static int
   84 g_bsd_modify(struct g_geom *gp, u_char *label)
   85 {
   86         int i, error;
   87         struct partition *ppp;
   88         struct g_slicer *gsp;
   89         struct g_consumer *cp;
   90         struct g_bsd_softc *ms;
   91         u_int secsize, u;
   92         off_t rawoffset, o;
   93         struct disklabel dl;
   94         MD5_CTX md5sum;
   95 
   96         g_topology_assert();
   97         gsp = gp->softc;
   98         ms = gsp->softc;
   99 
  100         error = bsd_disklabel_le_dec(label, &dl, MAXPARTITIONS);
  101         if (error) {
  102                 return (error);
  103         }
  104 
  105         /* Get dimensions of our device. */
  106         cp = LIST_FIRST(&gp->consumer);
  107         secsize = cp->provider->sectorsize;
  108 
  109         /* ... or a smaller sector size. */
  110         if (dl.d_secsize < secsize) {
  111                 return (EINVAL);
  112         }
  113 
  114         /* ... or a non-multiple sector size. */
  115         if (dl.d_secsize % secsize != 0) {
  116                 return (EINVAL);
  117         }
  118 
  119         /* Historical braindamage... */
  120         rawoffset = (off_t)dl.d_partitions[RAW_PART].p_offset * dl.d_secsize;
  121 
  122         for (i = 0; i < dl.d_npartitions; i++) {
  123                 ppp = &dl.d_partitions[i];
  124                 if (ppp->p_size == 0)
  125                         continue;
  126                 o = (off_t)ppp->p_offset * dl.d_secsize;
  127 
  128                 if (o < rawoffset)
  129                         rawoffset = 0;
  130         }
  131         
  132         if (rawoffset != 0 && (off_t)rawoffset != ms->mbroffset)
  133                 printf("WARNING: Expected rawoffset %jd, found %jd\n",
  134                     (intmax_t)ms->mbroffset/dl.d_secsize,
  135                     (intmax_t)rawoffset/dl.d_secsize);
  136 
  137         /* Don't munge open partitions. */
  138         for (i = 0; i < dl.d_npartitions; i++) {
  139                 ppp = &dl.d_partitions[i];
  140 
  141                 o = (off_t)ppp->p_offset * dl.d_secsize;
  142                 if (o == 0)
  143                         o = rawoffset;
  144                 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
  145                     o - rawoffset,
  146                     (off_t)ppp->p_size * dl.d_secsize,
  147                      dl.d_secsize,
  148                     "%s%c", gp->name, 'a' + i);
  149                 if (error)
  150                         return (error);
  151         }
  152 
  153         /* Look good, go for it... */
  154         for (u = 0; u < gsp->nslice; u++) {
  155                 ppp = &dl.d_partitions[u];
  156                 o = (off_t)ppp->p_offset * dl.d_secsize;
  157                 if (o == 0)
  158                         o = rawoffset;
  159                 g_slice_config(gp, u, G_SLICE_CONFIG_SET,
  160                     o - rawoffset,
  161                     (off_t)ppp->p_size * dl.d_secsize,
  162                      dl.d_secsize,
  163                     "%s%c", gp->name, 'a' + u);
  164         }
  165 
  166         /* Update our softc */
  167         ms->ondisk = dl;
  168         if (label != ms->label)
  169                 bcopy(label, ms->label, LABELSIZE);
  170         ms->rawoffset = rawoffset;
  171 
  172         /*
  173          * In order to avoid recursively attaching to the same
  174          * on-disk label (it's usually visible through the 'c'
  175          * partition) we calculate an MD5 and ask if other BSD's
  176          * below us love that label.  If they do, we don't.
  177          */
  178         MD5Init(&md5sum);
  179         MD5Update(&md5sum, ms->label, sizeof(ms->label));
  180         MD5Final(ms->labelsum, &md5sum);
  181 
  182         return (0);
  183 }
  184 
  185 /*
  186  * This is an internal helper function, called multiple times from the taste
  187  * function to try to locate a disklabel on the disk.  More civilized formats
  188  * will not need this, as there is only one possible place on disk to look
  189  * for the magic spot.
  190  */
  191 
  192 static int
  193 g_bsd_try(struct g_geom *gp, struct g_slicer *gsp, struct g_consumer *cp, int secsize, struct g_bsd_softc *ms, off_t offset)
  194 {
  195         int error;
  196         u_char *buf;
  197         struct disklabel *dl;
  198         off_t secoff;
  199 
  200         /*
  201          * We need to read entire aligned sectors, and we assume that the
  202          * disklabel does not span sectors, so one sector is enough.
  203          */
  204         error = 0;
  205         secoff = offset % secsize;
  206         buf = g_read_data(cp, offset - secoff, secsize, &error);
  207         if (buf == NULL || error != 0)
  208                 return (ENOENT);
  209 
  210         /* Decode into our native format. */
  211         dl = &ms->ondisk;
  212         error = bsd_disklabel_le_dec(buf + secoff, dl, MAXPARTITIONS);
  213         if (!error)
  214                 bcopy(buf + secoff, ms->label, LABELSIZE);
  215 
  216         /* Remember to free the buffer g_read_data() gave us. */
  217         g_free(buf);
  218 
  219         ms->labeloffset = offset;
  220         return (error);
  221 }
  222 
  223 /*
  224  * This function writes the current label to disk, possibly updating
  225  * the alpha SRM checksum.
  226  */
  227 
  228 static int
  229 g_bsd_writelabel(struct g_geom *gp, u_char *bootcode)
  230 {
  231         off_t secoff;
  232         u_int secsize;
  233         struct g_consumer *cp;
  234         struct g_slicer *gsp;
  235         struct g_bsd_softc *ms;
  236         u_char *buf;
  237         uint64_t sum;
  238         int error, i;
  239 
  240         gsp = gp->softc;
  241         ms = gsp->softc;
  242         cp = LIST_FIRST(&gp->consumer);
  243         /* Get sector size, we need it to read data. */
  244         secsize = cp->provider->sectorsize;
  245         secoff = ms->labeloffset % secsize;
  246         if (bootcode == NULL) {
  247                 buf = g_read_data(cp, ms->labeloffset - secoff, secsize, &error);
  248                 if (buf == NULL || error != 0)
  249                         return (error);
  250                 bcopy(ms->label, buf + secoff, sizeof(ms->label));
  251         } else {
  252                 buf = bootcode;
  253                 bcopy(ms->label, buf + ms->labeloffset, sizeof(ms->label));
  254         }
  255         if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
  256                 sum = 0;
  257                 for (i = 0; i < 63; i++)
  258                         sum += le64dec(buf + i * 8);
  259                 le64enc(buf + 504, sum);
  260         }
  261         if (bootcode == NULL) {
  262                 error = g_write_data(cp, ms->labeloffset - secoff, buf, secsize);
  263                 g_free(buf);
  264         } else {
  265                 error = g_write_data(cp, 0, bootcode, BBSIZE);
  266         }
  267         return(error);
  268 }
  269 
  270 /*
  271  * If the user tries to overwrite our disklabel through an open partition
  272  * or via a magicwrite config call, we end up here and try to prevent
  273  * footshooting as best we can.
  274  */
  275 static void
  276 g_bsd_hotwrite(void *arg, int flag)
  277 {
  278         struct bio *bp;
  279         struct g_geom *gp;
  280         struct g_slicer *gsp;
  281         struct g_slice *gsl;
  282         struct g_bsd_softc *ms;
  283         u_char *p;
  284         int error;
  285         
  286         g_topology_assert();
  287         /*
  288          * We should never get canceled, because that would amount to a removal
  289          * of the geom while there was outstanding I/O requests.
  290          */
  291         KASSERT(flag != EV_CANCEL, ("g_bsd_hotwrite cancelled"));
  292         bp = arg;
  293         gp = bp->bio_to->geom;
  294         gsp = gp->softc;
  295         ms = gsp->softc;
  296         gsl = &gsp->slices[bp->bio_to->index];
  297         p = (u_char*)bp->bio_data + ms->labeloffset 
  298             - (bp->bio_offset + gsl->offset);
  299         error = g_bsd_modify(gp, p);
  300         if (error) {
  301                 g_io_deliver(bp, EPERM);
  302                 return;
  303         }
  304         g_slice_finish_hot(bp);
  305 }
  306 
  307 /*-
  308  * This start routine is only called for non-trivial requests, all the
  309  * trivial ones are handled autonomously by the slice code.
  310  * For requests we handle here, we must call the g_io_deliver() on the
  311  * bio, and return non-zero to indicate to the slice code that we did so.
  312  * This code executes in the "DOWN" I/O path, this means:
  313  *    * No sleeping.
  314  *    * Don't grab the topology lock.
  315  *    * Don't call biowait, g_getattr(), g_setattr() or g_read_data()
  316  */
  317 static int
  318 g_bsd_ioctl(struct g_provider *pp, u_long cmd, void * data, struct thread *td)
  319 {
  320         struct g_geom *gp;
  321         struct g_bsd_softc *ms;
  322         struct g_slicer *gsp;
  323         u_char *label;
  324         int error;
  325 
  326         gp = pp->geom;
  327         gsp = gp->softc;
  328         ms = gsp->softc;
  329 
  330         switch(cmd) {
  331         case DIOCGDINFO:
  332                 /* Return a copy of the disklabel to userland. */
  333                 bsd_disklabel_le_dec(ms->label, data, MAXPARTITIONS);
  334                 return(0);
  335         case DIOCBSDBB: {
  336                 struct g_consumer *cp;
  337                 u_char *buf;
  338                 void *p;
  339                 int error, i;
  340                 uint64_t sum;
  341 
  342                 /* The disklabel to set is the ioctl argument. */
  343                 buf = g_malloc(BBSIZE, M_WAITOK);
  344                 p = *(void **)data;
  345                 error = copyin(p, buf, BBSIZE);
  346                 if (!error) {
  347                         /* XXX: Rude, but supposedly safe */
  348                         DROP_GIANT();
  349                         g_topology_lock();
  350                         /* Validate and modify our slice instance to match. */
  351                         error = g_bsd_modify(gp, buf + ms->labeloffset);
  352                         if (!error) {
  353                                 cp = LIST_FIRST(&gp->consumer);
  354                                 if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
  355                                         sum = 0;
  356                                         for (i = 0; i < 63; i++)
  357                                                 sum += le64dec(buf + i * 8);
  358                                         le64enc(buf + 504, sum);
  359                                 }
  360                                 error = g_write_data(cp, 0, buf, BBSIZE);
  361                         }
  362                         g_topology_unlock();
  363                         PICKUP_GIANT();
  364                 }
  365                 g_free(buf);
  366                 return (error);
  367         }
  368         case DIOCSDINFO:
  369         case DIOCWDINFO: {
  370                 label = g_malloc(LABELSIZE, M_WAITOK);
  371 
  372                 /* The disklabel to set is the ioctl argument. */
  373                 bsd_disklabel_le_enc(label, data);
  374 
  375                 DROP_GIANT();
  376                 g_topology_lock();
  377                 /* Validate and modify our slice instance to match. */
  378                 error = g_bsd_modify(gp, label);
  379                 if (error == 0 && cmd == DIOCWDINFO)
  380                         error = g_bsd_writelabel(gp, NULL);
  381                 g_topology_unlock();
  382                 PICKUP_GIANT();
  383                 g_free(label);
  384                 return(error);
  385         }
  386         default:
  387                 return (ENOIOCTL);
  388         }
  389 }
  390 
  391 static int
  392 g_bsd_start(struct bio *bp)
  393 {
  394         struct g_geom *gp;
  395         struct g_bsd_softc *ms;
  396         struct g_slicer *gsp;
  397 
  398         gp = bp->bio_to->geom;
  399         gsp = gp->softc;
  400         ms = gsp->softc;
  401         if (bp->bio_cmd == BIO_GETATTR) {
  402                 if (g_handleattr(bp, "BSD::labelsum", ms->labelsum,
  403                     sizeof(ms->labelsum)))
  404                         return (1);
  405         }
  406         return (0);
  407 }
  408 
  409 /*
  410  * Dump configuration information in XML format.
  411  * Notice that the function is called once for the geom and once for each
  412  * consumer and provider.  We let g_slice_dumpconf() do most of the work.
  413  */
  414 static void
  415 g_bsd_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
  416 {
  417         struct g_bsd_softc *ms;
  418         struct g_slicer *gsp;
  419 
  420         gsp = gp->softc;
  421         ms = gsp->softc;
  422         g_slice_dumpconf(sb, indent, gp, cp, pp);
  423         if (indent != NULL && pp == NULL && cp == NULL) {
  424                 sbuf_printf(sb, "%s<labeloffset>%jd</labeloffset>\n",
  425                     indent, (intmax_t)ms->labeloffset);
  426                 sbuf_printf(sb, "%s<rawoffset>%jd</rawoffset>\n",
  427                     indent, (intmax_t)ms->rawoffset);
  428                 sbuf_printf(sb, "%s<mbroffset>%jd</mbroffset>\n",
  429                     indent, (intmax_t)ms->mbroffset);
  430         } else if (pp != NULL) {
  431                 if (indent == NULL)
  432                         sbuf_printf(sb, " ty %d",
  433                             ms->ondisk.d_partitions[pp->index].p_fstype);
  434                 else
  435                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  436                             ms->ondisk.d_partitions[pp->index].p_fstype);
  437         }
  438 }
  439 
  440 /*
  441  * The taste function is called from the event-handler, with the topology
  442  * lock already held and a provider to examine.  The flags are unused.
  443  *
  444  * If flags == G_TF_NORMAL, the idea is to take a bite of the provider and
  445  * if we find valid, consistent magic on it, build a geom on it.
  446  * any magic bits which indicate that we should automatically put a BSD
  447  * geom on it.
  448  *
  449  * There may be cases where the operator would like to put a BSD-geom on
  450  * providers which do not meet all of the requirements.  This can be done
  451  * by instead passing the G_TF_INSIST flag, which will override these
  452  * checks.
  453  *
  454  * The final flags value is G_TF_TRANSPARENT, which instructs the method
  455  * to put a geom on top of the provider and configure it to be as transparent
  456  * as possible.  This is not really relevant to the BSD method and therefore
  457  * not implemented here.
  458  */
  459 
  460 static struct g_geom *
  461 g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
  462 {
  463         struct g_geom *gp;
  464         struct g_consumer *cp;
  465         int error, i;
  466         struct g_bsd_softc *ms;
  467         u_int secsize;
  468         struct g_slicer *gsp;
  469         u_char hash[16];
  470         MD5_CTX md5sum;
  471 
  472         g_trace(G_T_TOPOLOGY, "bsd_taste(%s,%s)", mp->name, pp->name);
  473         g_topology_assert();
  474 
  475         /* We don't implement transparent inserts. */
  476         if (flags == G_TF_TRANSPARENT)
  477                 return (NULL);
  478 
  479         /*
  480          * BSD labels are a subclass of the general "slicing" topology so
  481          * a lot of the work can be done by the common "slice" code.
  482          * Create a geom with space for MAXPARTITIONS providers, one consumer
  483          * and a softc structure for us.  Specify the provider to attach
  484          * the consumer to and our "start" routine for special requests.
  485          * The provider is opened with mode (1,0,0) so we can do reads
  486          * from it.
  487          */
  488         gp = g_slice_new(mp, MAXPARTITIONS, pp, &cp, &ms,
  489              sizeof(*ms), g_bsd_start);
  490         if (gp == NULL)
  491                 return (NULL);
  492 
  493         /*
  494          * Fill in the optional details, in our case we have a dumpconf
  495          * routine which the "slice" code should call at the right time
  496          */
  497         gp->dumpconf = g_bsd_dumpconf;
  498         gp->ioctl = g_bsd_ioctl;
  499 
  500         /* Get the geom_slicer softc from the geom. */
  501         gsp = gp->softc;
  502 
  503         /*
  504          * The do...while loop here allows us to have multiple escapes
  505          * using a simple "break".  This improves code clarity without
  506          * ending up in deep nesting and without using goto or come from.
  507          */
  508         do {
  509                 /*
  510                  * If the provider is an MBR we will only auto attach
  511                  * to type 165 slices in the G_TF_NORMAL case.  We will
  512                  * attach to any other type.
  513                  */
  514                 error = g_getattr("MBR::type", cp, &i);
  515                 if (!error) {
  516                         if (i != 165 && flags == G_TF_NORMAL)
  517                                 break;
  518                         error = g_getattr("MBR::offset", cp, &ms->mbroffset);
  519                         if (error)
  520                                 break;
  521                 }
  522 
  523                 /* Same thing if we are inside a PC98 */
  524                 error = g_getattr("PC98::type", cp, &i);
  525                 if (!error) {
  526                         if (i != 0xc494 && flags == G_TF_NORMAL)
  527                                 break;
  528                         error = g_getattr("PC98::offset", cp, &ms->mbroffset);
  529                         if (error)
  530                                 break;
  531                 }
  532 
  533                 /* Get sector size, we need it to read data. */
  534                 secsize = cp->provider->sectorsize;
  535                 if (secsize < 512)
  536                         break;
  537 
  538                 /* First look for a label at the start of the second sector. */
  539                 error = g_bsd_try(gp, gsp, cp, secsize, ms, secsize);
  540 
  541                 /* Next, look for alpha labels */
  542                 if (error)
  543                         error = g_bsd_try(gp, gsp, cp, secsize, ms,
  544                             ALPHA_LABEL_OFFSET);
  545 
  546                 /* If we didn't find a label, punt. */
  547                 if (error)
  548                         break;
  549 
  550                 /*
  551                  * In order to avoid recursively attaching to the same
  552                  * on-disk label (it's usually visible through the 'c'
  553                  * partition) we calculate an MD5 and ask if other BSD's
  554                  * below us love that label.  If they do, we don't.
  555                  */
  556                 MD5Init(&md5sum);
  557                 MD5Update(&md5sum, ms->label, sizeof(ms->label));
  558                 MD5Final(ms->labelsum, &md5sum);
  559 
  560                 error = g_getattr("BSD::labelsum", cp, &hash);
  561                 if (!error && !bcmp(ms->labelsum, hash, sizeof(hash)))
  562                         break;
  563 
  564                 /*
  565                  * Process the found disklabel, and modify our "slice"
  566                  * instance to match it, if possible.
  567                  */
  568                 error = g_bsd_modify(gp, ms->label);
  569         } while (0);
  570 
  571         /* Success or failure, we can close our provider now. */
  572         error = g_access_rel(cp, -1, 0, 0);
  573 
  574         /* If we have configured any providers, return the new geom. */
  575         if (gsp->nprovider > 0) {
  576                 g_slice_conf_hot(gp, 0, ms->labeloffset, LABELSIZE,
  577                     G_SLICE_HOT_ALLOW, G_SLICE_HOT_DENY, G_SLICE_HOT_CALL);
  578                 gsp->hot = g_bsd_hotwrite;
  579                 return (gp);
  580         }
  581         /*
  582          * ...else push the "self-destruct" button, by spoiling our own
  583          * consumer.  This triggers a call to g_slice_spoiled which will
  584          * dismantle what was setup.
  585          */
  586         g_slice_spoiled(cp);
  587         return (NULL);
  588 }
  589 
  590 struct h0h0 {
  591         struct g_geom *gp;
  592         struct g_bsd_softc *ms;
  593         u_char *label;
  594         int error;
  595 };
  596 
  597 static void
  598 g_bsd_callconfig(void *arg, int flag)
  599 {
  600         struct h0h0 *hp;
  601 
  602         hp = arg;
  603         hp->error = g_bsd_modify(hp->gp, hp->label);
  604         if (!hp->error)
  605                 hp->error = g_bsd_writelabel(hp->gp, NULL);
  606 }
  607 
  608 /*
  609  * NB! curthread is user process which GCTL'ed.
  610  */
  611 static void
  612 g_bsd_config(struct gctl_req *req, struct g_class *mp, char const *verb)
  613 {
  614         u_char *label;
  615         int error;
  616         struct h0h0 h0h0;
  617         struct g_geom *gp;
  618         struct g_slicer *gsp;
  619         struct g_consumer *cp;
  620         struct g_bsd_softc *ms;
  621 
  622         g_topology_assert();
  623         gp = gctl_get_geom(req, mp, "geom");
  624         if (gp == NULL)
  625                 return;
  626         cp = LIST_FIRST(&gp->consumer);
  627         gsp = gp->softc;
  628         ms = gsp->softc;
  629         if (!strcmp(verb, "read mbroffset")) {
  630                 gctl_set_param(req, "mbroffset",
  631                     &ms->mbroffset, sizeof(ms->mbroffset));
  632                 return;
  633         } else if (!strcmp(verb, "write label")) {
  634                 label = gctl_get_paraml(req, "label", LABELSIZE);
  635                 if (label == NULL)
  636                         return;
  637                 h0h0.gp = gp;
  638                 h0h0.ms = gsp->softc;
  639                 h0h0.label = label;
  640                 h0h0.error = -1;
  641                 /* XXX: Does this reference register with our selfdestruct code ? */
  642                 error = g_access_rel(cp, 1, 1, 1);
  643                 if (error) {
  644                         gctl_error(req, "could not access consumer");
  645                         return;
  646                 }
  647                 g_bsd_callconfig(&h0h0, 0);
  648                 error = h0h0.error;
  649                 g_access_rel(cp, -1, -1, -1);
  650         } else if (!strcmp(verb, "write bootcode")) {
  651                 label = gctl_get_paraml(req, "bootcode", BBSIZE);
  652                 if (label == NULL)
  653                         return;
  654                 /* XXX: Does this reference register with our selfdestruct code ? */
  655                 error = g_access_rel(cp, 1, 1, 1);
  656                 if (error) {
  657                         gctl_error(req, "could not access consumer");
  658                         return;
  659                 }
  660                 error = g_bsd_writelabel(gp, label);
  661                 g_access_rel(cp, -1, -1, -1);
  662         } else {
  663                 gctl_error(req, "Unknown verb parameter");
  664         }
  665 
  666         return;
  667 }
  668 
  669 /* Finally, register with GEOM infrastructure. */
  670 static struct g_class g_bsd_class = {
  671         .name = BSD_CLASS_NAME,
  672         .taste = g_bsd_taste,
  673         .ctlreq = g_bsd_config,
  674 };
  675 
  676 DECLARE_GEOM_CLASS(g_bsd_class, g_bsd);

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