The Design and Implementation of the FreeBSD Operating System, Second Edition
Now available: The Design and Implementation of the FreeBSD Operating System (Second Edition)


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sys/geom/geom_mbr.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  *
   20  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
   21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
   22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
   23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
   24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
   25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
   26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
   27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
   28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
   29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
   30  * SUCH DAMAGE.
   31  *
   32  * $FreeBSD: releng/5.1/sys/geom/geom_mbr.c 114517 2003-05-02 08:13:03Z phk $
   33  */
   34 
   35 #include <sys/param.h>
   36 #include <sys/errno.h>
   37 #include <sys/endian.h>
   38 #include <sys/systm.h>
   39 #include <sys/kernel.h>
   40 #include <sys/malloc.h>
   41 #include <sys/bio.h>
   42 #include <sys/lock.h>
   43 #include <sys/mutex.h>
   44 
   45 #include <sys/diskmbr.h>
   46 #include <sys/sbuf.h>
   47 #include <geom/geom.h>
   48 #include <geom/geom_slice.h>
   49 
   50 #define MBR_CLASS_NAME "MBR"
   51 #define MBREXT_CLASS_NAME "MBREXT"
   52 
   53 static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
   54         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   55         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   56         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   57         { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
   58 };
   59 
   60 static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
   61         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   62         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   63         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   64         { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
   65 };
   66 
   67 static void
   68 g_mbr_print(int i, struct dos_partition *dp)
   69 {
   70 
   71         printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
   72         printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
   73             dp->dp_shd, DPSECT(dp->dp_ssect));
   74         printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
   75             dp->dp_ehd, DPSECT(dp->dp_esect));
   76         printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
   77 }
   78 
   79 struct g_mbr_softc {
   80         int             type [NDOSPART];
   81         u_int           sectorsize;
   82         u_char          sec0[512];
   83 };
   84 
   85 static int
   86 g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0)
   87 {
   88         int i, error;
   89         off_t l[NDOSPART];
   90         struct dos_partition ndp[NDOSPART], *dp;
   91 
   92         g_topology_assert();
   93 
   94         if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
   95                 return (EBUSY);
   96 
   97         dp = ndp;
   98         for (i = 0; i < NDOSPART; i++) {
   99                 dos_partition_dec(
  100                     sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
  101                     dp + i);
  102                 if (bootverbose)
  103                         g_mbr_print(i, dp + i);
  104         }
  105         if ((!bcmp(dp, historical_bogus_partition_table,
  106             sizeof historical_bogus_partition_table)) ||
  107             (!bcmp(dp, historical_bogus_partition_table_fixed,
  108             sizeof historical_bogus_partition_table_fixed))) {
  109                 /*
  110                  * We will not allow people to write these from "the inside",
  111                  * Since properly selfdestructing takes too much code.  If 
  112                  * people really want to do this, they cannot have any
  113                  * providers of this geom open, and in that case they can just
  114                  * as easily overwrite the MBR in the parent device.
  115                  */
  116                 return(EBUSY);
  117         }
  118         for (i = 0; i < NDOSPART; i++) {
  119                 /* 
  120                  * A Protective MBR (PMBR) has a single partition of
  121                  * type 0xEE spanning the whole disk. Such a MBR
  122                  * protects a GPT on the disk from MBR tools that
  123                  * don't know anything about GPT. We're interpreting
  124                  * it a bit more loosely: any partition of type 0xEE
  125                  * is to be skipped as it doesn't contain any data
  126                  * that we should care about. We still allow other
  127                  * partitions to be present in the MBR. A PMBR will
  128                  * be handled correctly anyway.
  129                  */
  130                 if (dp[i].dp_typ == DOSPTYP_PMBR)
  131                         l[i] = 0;
  132                 else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
  133                         l[i] = 0;
  134                 else if (dp[i].dp_typ == 0)
  135                         l[i] = 0;
  136                 else
  137                         l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
  138                 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
  139                     (off_t)dp[i].dp_start * ms->sectorsize, l[i],
  140                     ms->sectorsize, "%ss%d", gp->name, 1 + i);
  141                 if (error)
  142                         return (error);
  143         }
  144         for (i = 0; i < NDOSPART; i++) {
  145                 ms->type[i] = dp[i].dp_typ;
  146                 g_slice_config(gp, i, G_SLICE_CONFIG_SET,
  147                     (off_t)dp[i].dp_start * ms->sectorsize, l[i],
  148                     ms->sectorsize, "%ss%d", gp->name, 1 + i);
  149         }
  150         bcopy(sec0, ms->sec0, 512);
  151         return (0);
  152 }
  153 
  154 static void
  155 g_mbr_ioctl(void *arg, int flag)
  156 {
  157         struct bio *bp;
  158         struct g_geom *gp;
  159         struct g_slicer *gsp;
  160         struct g_mbr_softc *ms;
  161         struct g_ioctl *gio;
  162         struct g_consumer *cp;
  163         u_char *sec0;
  164         int error;
  165 
  166         bp = arg;
  167         if (flag == EV_CANCEL) {
  168                 g_io_deliver(bp, ENXIO);
  169                 return;
  170         }
  171         gp = bp->bio_to->geom;
  172         gsp = gp->softc;
  173         ms = gsp->softc;
  174         gio = (struct g_ioctl *)bp->bio_data;
  175 
  176         /* The disklabel to set is the ioctl argument. */
  177         sec0 = gio->data;
  178 
  179         error = g_mbr_modify(gp, ms, sec0);
  180         if (error) {
  181                 g_io_deliver(bp, error);
  182                 return;
  183         }
  184         cp = LIST_FIRST(&gp->consumer);
  185         error = g_write_data(cp, 0, sec0, 512);
  186         g_io_deliver(bp, error);
  187 }
  188 
  189 
  190 static int
  191 g_mbr_start(struct bio *bp)
  192 {
  193         struct g_provider *pp;
  194         struct g_geom *gp;
  195         struct g_mbr_softc *mp;
  196         struct g_slicer *gsp;
  197         struct g_ioctl *gio;
  198         int idx, error;
  199 
  200         pp = bp->bio_to;
  201         idx = pp->index;
  202         gp = pp->geom;
  203         gsp = gp->softc;
  204         mp = gsp->softc;
  205         if (bp->bio_cmd == BIO_GETATTR) {
  206                 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
  207                         return (1);
  208                 if (g_handleattr_off_t(bp, "MBR::offset",
  209                     gsp->slices[idx].offset))
  210                         return (1);
  211         }
  212 
  213         /* We only handle ioctl(2) requests of the right format. */
  214         if (strcmp(bp->bio_attribute, "GEOM::ioctl"))
  215                 return (0);
  216         else if (bp->bio_length != sizeof(*gio))
  217                 return (0);
  218 
  219         /* Get hold of the ioctl parameters. */
  220         gio = (struct g_ioctl *)bp->bio_data;
  221 
  222         switch (gio->cmd) {
  223         case DIOCSMBR:
  224                 /*
  225                  * These we cannot do without the topology lock and some
  226                  * some I/O requests.  Ask the event-handler to schedule
  227                  * us in a less restricted environment.
  228                  */
  229                 error = g_post_event(g_mbr_ioctl, bp, M_NOWAIT, gp, NULL);
  230                 if (error)
  231                         g_io_deliver(bp, error);
  232                 /*
  233                  * We must return non-zero to indicate that we will deal
  234                  * with this bio, even though we have not done so yet.
  235                  */
  236                 return (1);
  237         default:
  238                 return (0);
  239         }
  240 
  241         return (0);
  242 }
  243 
  244 static void
  245 g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
  246 {
  247         struct g_mbr_softc *mp;
  248         struct g_slicer *gsp;
  249 
  250         gsp = gp->softc;
  251         mp = gsp->softc;
  252         g_slice_dumpconf(sb, indent, gp, cp, pp);
  253         if (pp != NULL) {
  254                 if (indent == NULL)
  255                         sbuf_printf(sb, " ty %d", mp->type[pp->index]);
  256                 else
  257                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  258                             mp->type[pp->index]);
  259         }
  260 }
  261 
  262 static struct g_geom *
  263 g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
  264 {
  265         struct g_geom *gp;
  266         struct g_consumer *cp;
  267         int error;
  268         struct g_mbr_softc *ms;
  269         struct g_slicer *gsp;
  270         u_int fwsectors, sectorsize;
  271         u_char *buf;
  272 
  273         g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
  274         g_topology_assert();
  275         gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
  276         if (gp == NULL)
  277                 return (NULL);
  278         gsp = gp->softc;
  279         g_topology_unlock();
  280         gp->dumpconf = g_mbr_dumpconf;
  281         do {
  282                 if (gp->rank != 2 && insist == 0)
  283                         break;
  284                 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
  285                 if (error)
  286                         fwsectors = 17;
  287                 sectorsize = cp->provider->sectorsize;
  288                 if (sectorsize < 512)
  289                         break;
  290                 ms->sectorsize = sectorsize;
  291                 buf = g_read_data(cp, 0, sectorsize, &error);
  292                 if (buf == NULL || error != 0)
  293                         break;
  294                 g_topology_lock();
  295                 g_mbr_modify(gp, ms, buf);
  296                 g_topology_unlock();
  297                 g_free(buf);
  298                 break;
  299         } while (0);
  300         g_topology_lock();
  301         g_access_rel(cp, -1, 0, 0);
  302         if (LIST_EMPTY(&gp->provider)) {
  303                 g_slice_spoiled(cp);
  304                 return (NULL);
  305         }
  306         return (gp);
  307 }
  308 
  309 static struct g_class g_mbr_class       = {
  310         .name = MBR_CLASS_NAME,
  311         .taste = g_mbr_taste,
  312         G_CLASS_INITIALIZER
  313 };
  314 
  315 DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
  316 
  317 #define NDOSEXTPART             32
  318 struct g_mbrext_softc {
  319         int             type [NDOSEXTPART];
  320 };
  321 
  322 static int
  323 g_mbrext_start(struct bio *bp)
  324 {
  325         struct g_provider *pp;
  326         struct g_geom *gp;
  327         struct g_mbrext_softc *mp;
  328         struct g_slicer *gsp;
  329         int idx;
  330 
  331         pp = bp->bio_to;
  332         idx = pp->index;
  333         gp = pp->geom;
  334         gsp = gp->softc;
  335         mp = gsp->softc;
  336         if (bp->bio_cmd == BIO_GETATTR) {
  337                 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
  338                         return (1);
  339         }
  340         return (0);
  341 }
  342 
  343 static void
  344 g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
  345 {
  346         struct g_mbrext_softc *mp;
  347         struct g_slicer *gsp;
  348 
  349         g_slice_dumpconf(sb, indent, gp, cp, pp);
  350         gsp = gp->softc;
  351         mp = gsp->softc;
  352         if (pp != NULL) {
  353                 if (indent == NULL)
  354                         sbuf_printf(sb, " ty %d", mp->type[pp->index]);
  355                 else
  356                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  357                             mp->type[pp->index]);
  358         }
  359 }
  360 
  361 static struct g_geom *
  362 g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
  363 {
  364         struct g_geom *gp;
  365         struct g_consumer *cp;
  366         int error, i, slice;
  367         struct g_mbrext_softc *ms;
  368         off_t off;
  369         u_char *buf;
  370         struct dos_partition dp[4];
  371         u_int fwsectors, sectorsize;
  372         struct g_slicer *gsp;
  373 
  374         g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
  375         g_topology_assert();
  376         if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
  377                 return (NULL);
  378         gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
  379             g_mbrext_start);
  380         if (gp == NULL)
  381                 return (NULL);
  382         gsp = gp->softc;
  383         g_topology_unlock();
  384         gp->dumpconf = g_mbrext_dumpconf;
  385         off = 0;
  386         slice = 0;
  387         do {
  388                 error = g_getattr("MBR::type", cp, &i);
  389                 if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
  390                         break;
  391                 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
  392                 if (error)
  393                         fwsectors = 17;
  394                 sectorsize = cp->provider->sectorsize;
  395                 if (sectorsize != 512)
  396                         break;
  397                 for (;;) {
  398                         buf = g_read_data(cp, off, sectorsize, &error);
  399                         if (buf == NULL || error != 0)
  400                                 break;
  401                         if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
  402                                 g_free(buf);
  403                                 break;
  404                         }
  405                         for (i = 0; i < NDOSPART; i++) 
  406                                 dos_partition_dec(
  407                                     buf + DOSPARTOFF + 
  408                                     i * sizeof(struct dos_partition), dp + i);
  409                         g_free(buf);
  410                         if (bootverbose) {
  411                                 printf("MBREXT Slice %d on %s:\n",
  412                                     slice + 5, gp->name);
  413                                 g_mbr_print(0, dp);
  414                                 g_mbr_print(1, dp + 1);
  415                         }
  416                         if ((dp[0].dp_flag & 0x7f) == 0 &&
  417                              dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
  418                                 g_topology_lock();
  419                                 g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
  420                                     (((off_t)dp[0].dp_start) << 9ULL) + off,
  421                                     ((off_t)dp[0].dp_size) << 9ULL,
  422                                     sectorsize,
  423                                     "%*.*s%d",
  424                                     strlen(gp->name) - 1,
  425                                     strlen(gp->name) - 1,
  426                                     gp->name,
  427                                     slice + 5);
  428                                 g_topology_unlock();
  429                                 ms->type[slice] = dp[0].dp_typ;
  430                                 slice++;
  431                         }
  432                         if (dp[1].dp_flag != 0)
  433                                 break;
  434                         if (dp[1].dp_typ != DOSPTYP_EXT)
  435                                 break;
  436                         if (dp[1].dp_size == 0)
  437                                 break;
  438                         off = ((off_t)dp[1].dp_start) << 9ULL;
  439                 }
  440                 break;
  441         } while (0);
  442         g_topology_lock();
  443         g_access_rel(cp, -1, 0, 0);
  444         if (LIST_EMPTY(&gp->provider)) {
  445                 g_slice_spoiled(cp);
  446                 return (NULL);
  447         }
  448         return (gp);
  449 }
  450 
  451 
  452 static struct g_class g_mbrext_class    = {
  453         .name = MBREXT_CLASS_NAME,
  454         .taste = g_mbrext_taste,
  455         G_CLASS_INITIALIZER
  456 };
  457 
  458 DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);

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