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 
   36 /*
   37  * This is the method for dealing with BSD disklabels.  It has been
   38  * extensively (by my standards at least) commented, in the vain hope that
   39  * it will serve as the source in future copy&paste operations.
   40  */
   41 
   42 #include <sys/cdefs.h>
   43 __FBSDID("$FreeBSD: releng/9.0/sys/geom/geom_bsd.c 223921 2011-07-11 05:22:31Z ae $");
   44 
   45 #include <sys/param.h>
   46 #include <sys/endian.h>
   47 #include <sys/systm.h>
   48 #include <sys/sysctl.h>
   49 #include <sys/kernel.h>
   50 #include <sys/fcntl.h>
   51 #include <sys/conf.h>
   52 #include <sys/bio.h>
   53 #include <sys/malloc.h>
   54 #include <sys/lock.h>
   55 #include <sys/mutex.h>
   56 #include <sys/md5.h>
   57 #include <sys/errno.h>
   58 #include <sys/disklabel.h>
   59 #include <sys/gpt.h>
   60 #include <sys/sbuf.h>
   61 #include <sys/uuid.h>
   62 #include <geom/geom.h>
   63 #include <geom/geom_slice.h>
   64 
   65 FEATURE(geom_bsd, "GEOM BSD disklabels support");
   66 
   67 #define BSD_CLASS_NAME "BSD"
   68 
   69 #define ALPHA_LABEL_OFFSET      64
   70 #define HISTORIC_LABEL_OFFSET   512
   71 
   72 #define LABELSIZE (148 + 16 * MAXPARTITIONS)
   73 
   74 static void g_bsd_hotwrite(void *arg, int flag);
   75 /*
   76  * Our private data about one instance.  All the rest is handled by the
   77  * slice code and stored in its softc, so this is just the stuff
   78  * specific to BSD disklabels.
   79  */
   80 struct g_bsd_softc {
   81         off_t   labeloffset;
   82         off_t   mbroffset;
   83         off_t   rawoffset;
   84         struct disklabel ondisk;
   85         u_char  label[LABELSIZE];
   86         u_char  labelsum[16];
   87 };
   88 
   89 /*
   90  * Modify our slicer to match proposed disklabel, if possible.
   91  * This is where we make sure we don't do something stupid.
   92  */
   93 static int
   94 g_bsd_modify(struct g_geom *gp, u_char *label)
   95 {
   96         int i, error;
   97         struct partition *ppp;
   98         struct g_slicer *gsp;
   99         struct g_consumer *cp;
  100         struct g_bsd_softc *ms;
  101         u_int secsize, u;
  102         off_t rawoffset, o;
  103         struct disklabel dl;
  104         MD5_CTX md5sum;
  105 
  106         g_topology_assert();
  107         gsp = gp->softc;
  108         ms = gsp->softc;
  109 
  110         error = bsd_disklabel_le_dec(label, &dl, MAXPARTITIONS);
  111         if (error) {
  112                 return (error);
  113         }
  114 
  115         /* Get dimensions of our device. */
  116         cp = LIST_FIRST(&gp->consumer);
  117         secsize = cp->provider->sectorsize;
  118 
  119         /* ... or a smaller sector size. */
  120         if (dl.d_secsize < secsize) {
  121                 return (EINVAL);
  122         }
  123 
  124         /* ... or a non-multiple sector size. */
  125         if (dl.d_secsize % secsize != 0) {
  126                 return (EINVAL);
  127         }
  128 
  129         /* Historical braindamage... */
  130         rawoffset = (off_t)dl.d_partitions[RAW_PART].p_offset * dl.d_secsize;
  131 
  132         for (i = 0; i < dl.d_npartitions; i++) {
  133                 ppp = &dl.d_partitions[i];
  134                 if (ppp->p_size == 0)
  135                         continue;
  136                 o = (off_t)ppp->p_offset * dl.d_secsize;
  137 
  138                 if (o < rawoffset)
  139                         rawoffset = 0;
  140         }
  141         
  142         if (rawoffset != 0 && (off_t)rawoffset != ms->mbroffset)
  143                 printf("WARNING: %s expected rawoffset %jd, found %jd\n",
  144                     gp->name,
  145                     (intmax_t)ms->mbroffset/dl.d_secsize,
  146                     (intmax_t)rawoffset/dl.d_secsize);
  147 
  148         /* Don't munge open partitions. */
  149         for (i = 0; i < dl.d_npartitions; i++) {
  150                 ppp = &dl.d_partitions[i];
  151 
  152                 o = (off_t)ppp->p_offset * dl.d_secsize;
  153                 if (o == 0)
  154                         o = rawoffset;
  155                 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
  156                     o - rawoffset,
  157                     (off_t)ppp->p_size * dl.d_secsize,
  158                      dl.d_secsize,
  159                     "%s%c", gp->name, 'a' + i);
  160                 if (error)
  161                         return (error);
  162         }
  163 
  164         /* Look good, go for it... */
  165         for (u = 0; u < gsp->nslice; u++) {
  166                 ppp = &dl.d_partitions[u];
  167                 o = (off_t)ppp->p_offset * dl.d_secsize;
  168                 if (o == 0)
  169                         o = rawoffset;
  170                 g_slice_config(gp, u, G_SLICE_CONFIG_SET,
  171                     o - rawoffset,
  172                     (off_t)ppp->p_size * dl.d_secsize,
  173                      dl.d_secsize,
  174                     "%s%c", gp->name, 'a' + u);
  175         }
  176 
  177         /* Update our softc */
  178         ms->ondisk = dl;
  179         if (label != ms->label)
  180                 bcopy(label, ms->label, LABELSIZE);
  181         ms->rawoffset = rawoffset;
  182 
  183         /*
  184          * In order to avoid recursively attaching to the same
  185          * on-disk label (it's usually visible through the 'c'
  186          * partition) we calculate an MD5 and ask if other BSD's
  187          * below us love that label.  If they do, we don't.
  188          */
  189         MD5Init(&md5sum);
  190         MD5Update(&md5sum, ms->label, sizeof(ms->label));
  191         MD5Final(ms->labelsum, &md5sum);
  192 
  193         return (0);
  194 }
  195 
  196 /*
  197  * This is an internal helper function, called multiple times from the taste
  198  * function to try to locate a disklabel on the disk.  More civilized formats
  199  * will not need this, as there is only one possible place on disk to look
  200  * for the magic spot.
  201  */
  202 
  203 static int
  204 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)
  205 {
  206         int error;
  207         u_char *buf;
  208         struct disklabel *dl;
  209         off_t secoff;
  210 
  211         /*
  212          * We need to read entire aligned sectors, and we assume that the
  213          * disklabel does not span sectors, so one sector is enough.
  214          */
  215         secoff = offset % secsize;
  216         buf = g_read_data(cp, offset - secoff, secsize, NULL);
  217         if (buf == NULL)
  218                 return (ENOENT);
  219 
  220         /* Decode into our native format. */
  221         dl = &ms->ondisk;
  222         error = bsd_disklabel_le_dec(buf + secoff, dl, MAXPARTITIONS);
  223         if (!error)
  224                 bcopy(buf + secoff, ms->label, LABELSIZE);
  225 
  226         /* Remember to free the buffer g_read_data() gave us. */
  227         g_free(buf);
  228 
  229         ms->labeloffset = offset;
  230         return (error);
  231 }
  232 
  233 /*
  234  * This function writes the current label to disk, possibly updating
  235  * the alpha SRM checksum.
  236  */
  237 
  238 static int
  239 g_bsd_writelabel(struct g_geom *gp, u_char *bootcode)
  240 {
  241         off_t secoff;
  242         u_int secsize;
  243         struct g_consumer *cp;
  244         struct g_slicer *gsp;
  245         struct g_bsd_softc *ms;
  246         u_char *buf;
  247         uint64_t sum;
  248         int error, i;
  249 
  250         gsp = gp->softc;
  251         ms = gsp->softc;
  252         cp = LIST_FIRST(&gp->consumer);
  253         /* Get sector size, we need it to read data. */
  254         secsize = cp->provider->sectorsize;
  255         secoff = ms->labeloffset % secsize;
  256         if (bootcode == NULL) {
  257                 buf = g_read_data(cp, ms->labeloffset - secoff, secsize, &error);
  258                 if (buf == NULL)
  259                         return (error);
  260                 bcopy(ms->label, buf + secoff, sizeof(ms->label));
  261         } else {
  262                 buf = bootcode;
  263                 bcopy(ms->label, buf + ms->labeloffset, sizeof(ms->label));
  264         }
  265         if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
  266                 sum = 0;
  267                 for (i = 0; i < 63; i++)
  268                         sum += le64dec(buf + i * 8);
  269                 le64enc(buf + 504, sum);
  270         }
  271         if (bootcode == NULL) {
  272                 error = g_write_data(cp, ms->labeloffset - secoff, buf, secsize);
  273                 g_free(buf);
  274         } else {
  275                 error = g_write_data(cp, 0, bootcode, BBSIZE);
  276         }
  277         return(error);
  278 }
  279 
  280 /*
  281  * If the user tries to overwrite our disklabel through an open partition
  282  * or via a magicwrite config call, we end up here and try to prevent
  283  * footshooting as best we can.
  284  */
  285 static void
  286 g_bsd_hotwrite(void *arg, int flag)
  287 {
  288         struct bio *bp;
  289         struct g_geom *gp;
  290         struct g_slicer *gsp;
  291         struct g_slice *gsl;
  292         struct g_bsd_softc *ms;
  293         u_char *p;
  294         int error;
  295         
  296         g_topology_assert();
  297         /*
  298          * We should never get canceled, because that would amount to a removal
  299          * of the geom while there was outstanding I/O requests.
  300          */
  301         KASSERT(flag != EV_CANCEL, ("g_bsd_hotwrite cancelled"));
  302         bp = arg;
  303         gp = bp->bio_to->geom;
  304         gsp = gp->softc;
  305         ms = gsp->softc;
  306         gsl = &gsp->slices[bp->bio_to->index];
  307         p = (u_char*)bp->bio_data + ms->labeloffset 
  308             - (bp->bio_offset + gsl->offset);
  309         error = g_bsd_modify(gp, p);
  310         if (error) {
  311                 g_io_deliver(bp, EPERM);
  312                 return;
  313         }
  314         g_slice_finish_hot(bp);
  315 }
  316 
  317 /*-
  318  * This start routine is only called for non-trivial requests, all the
  319  * trivial ones are handled autonomously by the slice code.
  320  * For requests we handle here, we must call the g_io_deliver() on the
  321  * bio, and return non-zero to indicate to the slice code that we did so.
  322  * This code executes in the "DOWN" I/O path, this means:
  323  *    * No sleeping.
  324  *    * Don't grab the topology lock.
  325  *    * Don't call biowait, g_getattr(), g_setattr() or g_read_data()
  326  */
  327 static int
  328 g_bsd_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct thread *td)
  329 {
  330         struct g_geom *gp;
  331         struct g_bsd_softc *ms;
  332         struct g_slicer *gsp;
  333         u_char *label;
  334         int error;
  335 
  336         gp = pp->geom;
  337         gsp = gp->softc;
  338         ms = gsp->softc;
  339 
  340         switch(cmd) {
  341         case DIOCGDINFO:
  342                 /* Return a copy of the disklabel to userland. */
  343                 bsd_disklabel_le_dec(ms->label, data, MAXPARTITIONS);
  344                 return(0);
  345         case DIOCBSDBB: {
  346                 struct g_consumer *cp;
  347                 u_char *buf;
  348                 void *p;
  349                 int error, i;
  350                 uint64_t sum;
  351 
  352                 if (!(fflag & FWRITE))
  353                         return (EPERM);
  354                 /* The disklabel to set is the ioctl argument. */
  355                 buf = g_malloc(BBSIZE, M_WAITOK);
  356                 p = *(void **)data;
  357                 error = copyin(p, buf, BBSIZE);
  358                 if (!error) {
  359                         /* XXX: Rude, but supposedly safe */
  360                         DROP_GIANT();
  361                         g_topology_lock();
  362                         /* Validate and modify our slice instance to match. */
  363                         error = g_bsd_modify(gp, buf + ms->labeloffset);
  364                         if (!error) {
  365                                 cp = LIST_FIRST(&gp->consumer);
  366                                 if (ms->labeloffset == ALPHA_LABEL_OFFSET) {
  367                                         sum = 0;
  368                                         for (i = 0; i < 63; i++)
  369                                                 sum += le64dec(buf + i * 8);
  370                                         le64enc(buf + 504, sum);
  371                                 }
  372                                 error = g_write_data(cp, 0, buf, BBSIZE);
  373                         }
  374                         g_topology_unlock();
  375                         PICKUP_GIANT();
  376                 }
  377                 g_free(buf);
  378                 return (error);
  379         }
  380         case DIOCSDINFO:
  381         case DIOCWDINFO: {
  382                 if (!(fflag & FWRITE))
  383                         return (EPERM);
  384                 label = g_malloc(LABELSIZE, M_WAITOK);
  385                 /* The disklabel to set is the ioctl argument. */
  386                 bsd_disklabel_le_enc(label, data);
  387 
  388                 DROP_GIANT();
  389                 g_topology_lock();
  390                 /* Validate and modify our slice instance to match. */
  391                 error = g_bsd_modify(gp, label);
  392                 if (error == 0 && cmd == DIOCWDINFO)
  393                         error = g_bsd_writelabel(gp, NULL);
  394                 g_topology_unlock();
  395                 PICKUP_GIANT();
  396                 g_free(label);
  397                 return(error);
  398         }
  399         default:
  400                 return (ENOIOCTL);
  401         }
  402 }
  403 
  404 static int
  405 g_bsd_start(struct bio *bp)
  406 {
  407         struct g_geom *gp;
  408         struct g_bsd_softc *ms;
  409         struct g_slicer *gsp;
  410 
  411         gp = bp->bio_to->geom;
  412         gsp = gp->softc;
  413         ms = gsp->softc;
  414         if (bp->bio_cmd == BIO_GETATTR) {
  415                 if (g_handleattr(bp, "BSD::labelsum", ms->labelsum,
  416                     sizeof(ms->labelsum)))
  417                         return (1);
  418         }
  419         return (0);
  420 }
  421 
  422 /*
  423  * Dump configuration information in XML format.
  424  * Notice that the function is called once for the geom and once for each
  425  * consumer and provider.  We let g_slice_dumpconf() do most of the work.
  426  */
  427 static void
  428 g_bsd_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp, struct g_provider *pp)
  429 {
  430         struct g_bsd_softc *ms;
  431         struct g_slicer *gsp;
  432 
  433         gsp = gp->softc;
  434         ms = gsp->softc;
  435         g_slice_dumpconf(sb, indent, gp, cp, pp);
  436         if (indent != NULL && pp == NULL && cp == NULL) {
  437                 sbuf_printf(sb, "%s<labeloffset>%jd</labeloffset>\n",
  438                     indent, (intmax_t)ms->labeloffset);
  439                 sbuf_printf(sb, "%s<rawoffset>%jd</rawoffset>\n",
  440                     indent, (intmax_t)ms->rawoffset);
  441                 sbuf_printf(sb, "%s<mbroffset>%jd</mbroffset>\n",
  442                     indent, (intmax_t)ms->mbroffset);
  443         } else if (pp != NULL) {
  444                 if (indent == NULL)
  445                         sbuf_printf(sb, " ty %d",
  446                             ms->ondisk.d_partitions[pp->index].p_fstype);
  447                 else
  448                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  449                             ms->ondisk.d_partitions[pp->index].p_fstype);
  450         }
  451 }
  452 
  453 /*
  454  * The taste function is called from the event-handler, with the topology
  455  * lock already held and a provider to examine.  The flags are unused.
  456  *
  457  * If flags == G_TF_NORMAL, the idea is to take a bite of the provider and
  458  * if we find valid, consistent magic on it, build a geom on it.
  459  *
  460  * There may be cases where the operator would like to put a BSD-geom on
  461  * providers which do not meet all of the requirements.  This can be done
  462  * by instead passing the G_TF_INSIST flag, which will override these
  463  * checks.
  464  *
  465  * The final flags value is G_TF_TRANSPARENT, which instructs the method
  466  * to put a geom on top of the provider and configure it to be as transparent
  467  * as possible.  This is not really relevant to the BSD method and therefore
  468  * not implemented here.
  469  */
  470 
  471 static struct uuid freebsd_slice = GPT_ENT_TYPE_FREEBSD;
  472 
  473 static struct g_geom *
  474 g_bsd_taste(struct g_class *mp, struct g_provider *pp, int flags)
  475 {
  476         struct g_geom *gp;
  477         struct g_consumer *cp;
  478         int error, i;
  479         struct g_bsd_softc *ms;
  480         u_int secsize;
  481         struct g_slicer *gsp;
  482         u_char hash[16];
  483         MD5_CTX md5sum;
  484         struct uuid uuid;
  485 
  486         g_trace(G_T_TOPOLOGY, "bsd_taste(%s,%s)", mp->name, pp->name);
  487         g_topology_assert();
  488 
  489         /* We don't implement transparent inserts. */
  490         if (flags == G_TF_TRANSPARENT)
  491                 return (NULL);
  492 
  493         /*
  494          * BSD labels are a subclass of the general "slicing" topology so
  495          * a lot of the work can be done by the common "slice" code.
  496          * Create a geom with space for MAXPARTITIONS providers, one consumer
  497          * and a softc structure for us.  Specify the provider to attach
  498          * the consumer to and our "start" routine for special requests.
  499          * The provider is opened with mode (1,0,0) so we can do reads
  500          * from it.
  501          */
  502         gp = g_slice_new(mp, MAXPARTITIONS, pp, &cp, &ms,
  503              sizeof(*ms), g_bsd_start);
  504         if (gp == NULL)
  505                 return (NULL);
  506 
  507         /* Get the geom_slicer softc from the geom. */
  508         gsp = gp->softc;
  509 
  510         /*
  511          * The do...while loop here allows us to have multiple escapes
  512          * using a simple "break".  This improves code clarity without
  513          * ending up in deep nesting and without using goto or come from.
  514          */
  515         do {
  516                 /*
  517                  * If the provider is an MBR we will only auto attach
  518                  * to type 165 slices in the G_TF_NORMAL case.  We will
  519                  * attach to any other type.
  520                  */
  521                 error = g_getattr("MBR::type", cp, &i);
  522                 if (!error) {
  523                         if (i != 165 && flags == G_TF_NORMAL)
  524                                 break;
  525                         error = g_getattr("MBR::offset", cp, &ms->mbroffset);
  526                         if (error)
  527                                 break;
  528                 }
  529 
  530                 /* Same thing if we are inside a PC98 */
  531                 error = g_getattr("PC98::type", cp, &i);
  532                 if (!error) {
  533                         if (i != 0xc494 && flags == G_TF_NORMAL)
  534                                 break;
  535                         error = g_getattr("PC98::offset", cp, &ms->mbroffset);
  536                         if (error)
  537                                 break;
  538                 }
  539 
  540                 /* Same thing if we are inside a GPT */
  541                 error = g_getattr("GPT::type", cp, &uuid);
  542                 if (!error) {
  543                         if (memcmp(&uuid, &freebsd_slice, sizeof(uuid)) != 0 &&
  544                             flags == G_TF_NORMAL)
  545                                 break;
  546                 }
  547 
  548                 /* Get sector size, we need it to read data. */
  549                 secsize = cp->provider->sectorsize;
  550                 if (secsize < 512)
  551                         break;
  552 
  553                 /* First look for a label at the start of the second sector. */
  554                 error = g_bsd_try(gp, gsp, cp, secsize, ms, secsize);
  555 
  556                 /*
  557                  * If sector size is not 512 the label still can be at
  558                  * offset 512, not at the start of the second sector. At least
  559                  * it's true for labels created by the FreeBSD's bsdlabel(8).
  560                  */
  561                 if (error && secsize != HISTORIC_LABEL_OFFSET)
  562                         error = g_bsd_try(gp, gsp, cp, secsize, ms,
  563                             HISTORIC_LABEL_OFFSET);
  564 
  565                 /* Next, look for alpha labels */
  566                 if (error)
  567                         error = g_bsd_try(gp, gsp, cp, secsize, ms,
  568                             ALPHA_LABEL_OFFSET);
  569 
  570                 /* If we didn't find a label, punt. */
  571                 if (error)
  572                         break;
  573 
  574                 /*
  575                  * In order to avoid recursively attaching to the same
  576                  * on-disk label (it's usually visible through the 'c'
  577                  * partition) we calculate an MD5 and ask if other BSD's
  578                  * below us love that label.  If they do, we don't.
  579                  */
  580                 MD5Init(&md5sum);
  581                 MD5Update(&md5sum, ms->label, sizeof(ms->label));
  582                 MD5Final(ms->labelsum, &md5sum);
  583 
  584                 error = g_getattr("BSD::labelsum", cp, &hash);
  585                 if (!error && !bcmp(ms->labelsum, hash, sizeof(hash)))
  586                         break;
  587 
  588                 /*
  589                  * Process the found disklabel, and modify our "slice"
  590                  * instance to match it, if possible.
  591                  */
  592                 error = g_bsd_modify(gp, ms->label);
  593         } while (0);
  594 
  595         /* Success or failure, we can close our provider now. */
  596         g_access(cp, -1, 0, 0);
  597 
  598         /* If we have configured any providers, return the new geom. */
  599         if (gsp->nprovider > 0) {
  600                 g_slice_conf_hot(gp, 0, ms->labeloffset, LABELSIZE,
  601                     G_SLICE_HOT_ALLOW, G_SLICE_HOT_DENY, G_SLICE_HOT_CALL);
  602                 gsp->hot = g_bsd_hotwrite;
  603                 return (gp);
  604         }
  605         /*
  606          * ...else push the "self-destruct" button, by spoiling our own
  607          * consumer.  This triggers a call to g_slice_spoiled which will
  608          * dismantle what was setup.
  609          */
  610         g_slice_spoiled(cp);
  611         return (NULL);
  612 }
  613 
  614 struct h0h0 {
  615         struct g_geom *gp;
  616         struct g_bsd_softc *ms;
  617         u_char *label;
  618         int error;
  619 };
  620 
  621 static void
  622 g_bsd_callconfig(void *arg, int flag)
  623 {
  624         struct h0h0 *hp;
  625 
  626         hp = arg;
  627         hp->error = g_bsd_modify(hp->gp, hp->label);
  628         if (!hp->error)
  629                 hp->error = g_bsd_writelabel(hp->gp, NULL);
  630 }
  631 
  632 /*
  633  * NB! curthread is user process which GCTL'ed.
  634  */
  635 static void
  636 g_bsd_config(struct gctl_req *req, struct g_class *mp, char const *verb)
  637 {
  638         u_char *label;
  639         int error;
  640         struct h0h0 h0h0;
  641         struct g_geom *gp;
  642         struct g_slicer *gsp;
  643         struct g_consumer *cp;
  644         struct g_bsd_softc *ms;
  645 
  646         g_topology_assert();
  647         gp = gctl_get_geom(req, mp, "geom");
  648         if (gp == NULL)
  649                 return;
  650         cp = LIST_FIRST(&gp->consumer);
  651         gsp = gp->softc;
  652         ms = gsp->softc;
  653         if (!strcmp(verb, "read mbroffset")) {
  654                 gctl_set_param_err(req, "mbroffset", &ms->mbroffset,
  655                     sizeof(ms->mbroffset));
  656                 return;
  657         } else if (!strcmp(verb, "write label")) {
  658                 label = gctl_get_paraml(req, "label", LABELSIZE);
  659                 if (label == NULL)
  660                         return;
  661                 h0h0.gp = gp;
  662                 h0h0.ms = gsp->softc;
  663                 h0h0.label = label;
  664                 h0h0.error = -1;
  665                 /* XXX: Does this reference register with our selfdestruct code ? */
  666                 error = g_access(cp, 1, 1, 1);
  667                 if (error) {
  668                         gctl_error(req, "could not access consumer");
  669                         return;
  670                 }
  671                 g_bsd_callconfig(&h0h0, 0);
  672                 error = h0h0.error;
  673                 g_access(cp, -1, -1, -1);
  674         } else if (!strcmp(verb, "write bootcode")) {
  675                 label = gctl_get_paraml(req, "bootcode", BBSIZE);
  676                 if (label == NULL)
  677                         return;
  678                 /* XXX: Does this reference register with our selfdestruct code ? */
  679                 error = g_access(cp, 1, 1, 1);
  680                 if (error) {
  681                         gctl_error(req, "could not access consumer");
  682                         return;
  683                 }
  684                 error = g_bsd_writelabel(gp, label);
  685                 g_access(cp, -1, -1, -1);
  686         } else {
  687                 gctl_error(req, "Unknown verb parameter");
  688         }
  689 
  690         return;
  691 }
  692 
  693 /* Finally, register with GEOM infrastructure. */
  694 static struct g_class g_bsd_class = {
  695         .name = BSD_CLASS_NAME,
  696         .version = G_VERSION,
  697         .taste = g_bsd_taste,
  698         .ctlreq = g_bsd_config,
  699         .dumpconf = g_bsd_dumpconf,
  700         .ioctl = g_bsd_ioctl,
  701 };
  702 
  703 DECLARE_GEOM_CLASS(g_bsd_class, g_bsd);

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