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 
   33 #include <sys/cdefs.h>
   34 __FBSDID("$FreeBSD: releng/5.2/sys/geom/geom_mbr.c 119660 2003-09-01 20:45:32Z phk $");
   35 
   36 #include <sys/param.h>
   37 #include <sys/errno.h>
   38 #include <sys/endian.h>
   39 #include <sys/systm.h>
   40 #include <sys/kernel.h>
   41 #include <sys/malloc.h>
   42 #include <sys/bio.h>
   43 #include <sys/lock.h>
   44 #include <sys/mutex.h>
   45 
   46 #include <sys/diskmbr.h>
   47 #include <sys/sbuf.h>
   48 #include <geom/geom.h>
   49 #include <geom/geom_slice.h>
   50 
   51 #define MBR_CLASS_NAME "MBR"
   52 #define MBREXT_CLASS_NAME "MBREXT"
   53 
   54 static struct dos_partition historical_bogus_partition_table[NDOSPART] = {
   55         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   56         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   57         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   58         { 0x80, 0, 1, 0, DOSPTYP_386BSD, 255, 255, 255, 0, 50000, },
   59 };
   60 
   61 static struct dos_partition historical_bogus_partition_table_fixed[NDOSPART] = {
   62         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   63         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   64         { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, },
   65         { 0x80, 0, 1, 0, DOSPTYP_386BSD, 254, 255, 255, 0, 50000, },
   66 };
   67 
   68 static void
   69 g_mbr_print(int i, struct dos_partition *dp)
   70 {
   71 
   72         printf("[%d] f:%02x typ:%d", i, dp->dp_flag, dp->dp_typ);
   73         printf(" s(CHS):%d/%d/%d", DPCYL(dp->dp_scyl, dp->dp_ssect),
   74             dp->dp_shd, DPSECT(dp->dp_ssect));
   75         printf(" e(CHS):%d/%d/%d", DPCYL(dp->dp_ecyl, dp->dp_esect),
   76             dp->dp_ehd, DPSECT(dp->dp_esect));
   77         printf(" s:%d l:%d\n", dp->dp_start, dp->dp_size);
   78 }
   79 
   80 struct g_mbr_softc {
   81         int             type [NDOSPART];
   82         u_int           sectorsize;
   83         u_char          sec0[512];
   84 };
   85 
   86 static int
   87 g_mbr_modify(struct g_geom *gp, struct g_mbr_softc *ms, u_char *sec0)
   88 {
   89         int i, error;
   90         off_t l[NDOSPART];
   91         struct dos_partition ndp[NDOSPART], *dp;
   92 
   93         g_topology_assert();
   94 
   95         if (sec0[0x1fe] != 0x55 && sec0[0x1ff] != 0xaa)
   96                 return (EBUSY);
   97 
   98         dp = ndp;
   99         for (i = 0; i < NDOSPART; i++) {
  100                 dos_partition_dec(
  101                     sec0 + DOSPARTOFF + i * sizeof(struct dos_partition),
  102                     dp + i);
  103                 if (bootverbose)
  104                         g_mbr_print(i, dp + i);
  105         }
  106         if ((!bcmp(dp, historical_bogus_partition_table,
  107             sizeof historical_bogus_partition_table)) ||
  108             (!bcmp(dp, historical_bogus_partition_table_fixed,
  109             sizeof historical_bogus_partition_table_fixed))) {
  110                 /*
  111                  * We will not allow people to write these from "the inside",
  112                  * Since properly selfdestructing takes too much code.  If 
  113                  * people really want to do this, they cannot have any
  114                  * providers of this geom open, and in that case they can just
  115                  * as easily overwrite the MBR in the parent device.
  116                  */
  117                 return(EBUSY);
  118         }
  119         for (i = 0; i < NDOSPART; i++) {
  120                 /* 
  121                  * A Protective MBR (PMBR) has a single partition of
  122                  * type 0xEE spanning the whole disk. Such a MBR
  123                  * protects a GPT on the disk from MBR tools that
  124                  * don't know anything about GPT. We're interpreting
  125                  * it a bit more loosely: any partition of type 0xEE
  126                  * is to be skipped as it doesn't contain any data
  127                  * that we should care about. We still allow other
  128                  * partitions to be present in the MBR. A PMBR will
  129                  * be handled correctly anyway.
  130                  */
  131                 if (dp[i].dp_typ == DOSPTYP_PMBR)
  132                         l[i] = 0;
  133                 else if (dp[i].dp_flag != 0 && dp[i].dp_flag != 0x80)
  134                         l[i] = 0;
  135                 else if (dp[i].dp_typ == 0)
  136                         l[i] = 0;
  137                 else
  138                         l[i] = (off_t)dp[i].dp_size * ms->sectorsize;
  139                 error = g_slice_config(gp, i, G_SLICE_CONFIG_CHECK,
  140                     (off_t)dp[i].dp_start * ms->sectorsize, l[i],
  141                     ms->sectorsize, "%ss%d", gp->name, 1 + i);
  142                 if (error)
  143                         return (error);
  144         }
  145         for (i = 0; i < NDOSPART; i++) {
  146                 ms->type[i] = dp[i].dp_typ;
  147                 g_slice_config(gp, i, G_SLICE_CONFIG_SET,
  148                     (off_t)dp[i].dp_start * ms->sectorsize, l[i],
  149                     ms->sectorsize, "%ss%d", gp->name, 1 + i);
  150         }
  151         bcopy(sec0, ms->sec0, 512);
  152         return (0);
  153 }
  154 
  155 static int
  156 g_mbr_ioctl(struct g_provider *pp, u_long cmd, void *data, struct thread *td)
  157 {
  158         struct g_geom *gp;
  159         struct g_mbr_softc *ms;
  160         struct g_slicer *gsp;
  161         struct g_consumer *cp;
  162         int error;
  163 
  164         gp = pp->geom;
  165         gsp = gp->softc;
  166         ms = gsp->softc;
  167 
  168         switch(cmd) {
  169         case DIOCSMBR: {
  170                 DROP_GIANT();
  171                 g_topology_lock();
  172                 /* Validate and modify our slicer instance to match. */
  173                 error = g_mbr_modify(gp, ms, data);
  174                 cp = LIST_FIRST(&gp->consumer);
  175                 error = g_write_data(cp, 0, data, 512);
  176                 g_topology_unlock();
  177                 PICKUP_GIANT();
  178                 return(error);
  179         }
  180         default:
  181                 return (ENOIOCTL);
  182         }
  183 }
  184 
  185 static int
  186 g_mbr_start(struct bio *bp)
  187 {
  188         struct g_provider *pp;
  189         struct g_geom *gp;
  190         struct g_mbr_softc *mp;
  191         struct g_slicer *gsp;
  192         int idx;
  193 
  194         pp = bp->bio_to;
  195         idx = pp->index;
  196         gp = pp->geom;
  197         gsp = gp->softc;
  198         mp = gsp->softc;
  199         if (bp->bio_cmd == BIO_GETATTR) {
  200                 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
  201                         return (1);
  202                 if (g_handleattr_off_t(bp, "MBR::offset",
  203                     gsp->slices[idx].offset))
  204                         return (1);
  205         }
  206 
  207         return (0);
  208 }
  209 
  210 static void
  211 g_mbr_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
  212 {
  213         struct g_mbr_softc *mp;
  214         struct g_slicer *gsp;
  215 
  216         gsp = gp->softc;
  217         mp = gsp->softc;
  218         g_slice_dumpconf(sb, indent, gp, cp, pp);
  219         if (pp != NULL) {
  220                 if (indent == NULL)
  221                         sbuf_printf(sb, " ty %d", mp->type[pp->index]);
  222                 else
  223                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  224                             mp->type[pp->index]);
  225         }
  226 }
  227 
  228 static struct g_geom *
  229 g_mbr_taste(struct g_class *mp, struct g_provider *pp, int insist)
  230 {
  231         struct g_geom *gp;
  232         struct g_consumer *cp;
  233         int error;
  234         struct g_mbr_softc *ms;
  235         u_int fwsectors, sectorsize;
  236         u_char *buf;
  237 
  238         g_trace(G_T_TOPOLOGY, "mbr_taste(%s,%s)", mp->name, pp->name);
  239         g_topology_assert();
  240         gp = g_slice_new(mp, NDOSPART, pp, &cp, &ms, sizeof *ms, g_mbr_start);
  241         if (gp == NULL)
  242                 return (NULL);
  243         g_topology_unlock();
  244         gp->dumpconf = g_mbr_dumpconf;
  245         gp->ioctl = g_mbr_ioctl;
  246         do {
  247                 if (gp->rank != 2 && insist == 0)
  248                         break;
  249                 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
  250                 if (error)
  251                         fwsectors = 17;
  252                 sectorsize = cp->provider->sectorsize;
  253                 if (sectorsize < 512)
  254                         break;
  255                 ms->sectorsize = sectorsize;
  256                 buf = g_read_data(cp, 0, sectorsize, &error);
  257                 if (buf == NULL || error != 0)
  258                         break;
  259                 g_topology_lock();
  260                 g_mbr_modify(gp, ms, buf);
  261                 g_topology_unlock();
  262                 g_free(buf);
  263                 break;
  264         } while (0);
  265         g_topology_lock();
  266         g_access_rel(cp, -1, 0, 0);
  267         if (LIST_EMPTY(&gp->provider)) {
  268                 g_slice_spoiled(cp);
  269                 return (NULL);
  270         }
  271         return (gp);
  272 }
  273 
  274 static struct g_class g_mbr_class       = {
  275         .name = MBR_CLASS_NAME,
  276         .taste = g_mbr_taste,
  277 };
  278 
  279 DECLARE_GEOM_CLASS(g_mbr_class, g_mbr);
  280 
  281 #define NDOSEXTPART             32
  282 struct g_mbrext_softc {
  283         int             type [NDOSEXTPART];
  284 };
  285 
  286 static int
  287 g_mbrext_start(struct bio *bp)
  288 {
  289         struct g_provider *pp;
  290         struct g_geom *gp;
  291         struct g_mbrext_softc *mp;
  292         struct g_slicer *gsp;
  293         int idx;
  294 
  295         pp = bp->bio_to;
  296         idx = pp->index;
  297         gp = pp->geom;
  298         gsp = gp->softc;
  299         mp = gsp->softc;
  300         if (bp->bio_cmd == BIO_GETATTR) {
  301                 if (g_handleattr_int(bp, "MBR::type", mp->type[idx]))
  302                         return (1);
  303         }
  304         return (0);
  305 }
  306 
  307 static void
  308 g_mbrext_dumpconf(struct sbuf *sb, const char *indent, struct g_geom *gp, struct g_consumer *cp __unused, struct g_provider *pp)
  309 {
  310         struct g_mbrext_softc *mp;
  311         struct g_slicer *gsp;
  312 
  313         g_slice_dumpconf(sb, indent, gp, cp, pp);
  314         gsp = gp->softc;
  315         mp = gsp->softc;
  316         if (pp != NULL) {
  317                 if (indent == NULL)
  318                         sbuf_printf(sb, " ty %d", mp->type[pp->index]);
  319                 else
  320                         sbuf_printf(sb, "%s<type>%d</type>\n", indent,
  321                             mp->type[pp->index]);
  322         }
  323 }
  324 
  325 static struct g_geom *
  326 g_mbrext_taste(struct g_class *mp, struct g_provider *pp, int insist __unused)
  327 {
  328         struct g_geom *gp;
  329         struct g_consumer *cp;
  330         int error, i, slice;
  331         struct g_mbrext_softc *ms;
  332         off_t off;
  333         u_char *buf;
  334         struct dos_partition dp[4];
  335         u_int fwsectors, sectorsize;
  336 
  337         g_trace(G_T_TOPOLOGY, "g_mbrext_taste(%s,%s)", mp->name, pp->name);
  338         g_topology_assert();
  339         if (strcmp(pp->geom->class->name, MBR_CLASS_NAME))
  340                 return (NULL);
  341         gp = g_slice_new(mp, NDOSEXTPART, pp, &cp, &ms, sizeof *ms,
  342             g_mbrext_start);
  343         if (gp == NULL)
  344                 return (NULL);
  345         g_topology_unlock();
  346         gp->dumpconf = g_mbrext_dumpconf;
  347         off = 0;
  348         slice = 0;
  349         do {
  350                 error = g_getattr("MBR::type", cp, &i);
  351                 if (error || (i != DOSPTYP_EXT && i != DOSPTYP_EXTLBA))
  352                         break;
  353                 error = g_getattr("GEOM::fwsectors", cp, &fwsectors);
  354                 if (error)
  355                         fwsectors = 17;
  356                 sectorsize = cp->provider->sectorsize;
  357                 if (sectorsize != 512)
  358                         break;
  359                 for (;;) {
  360                         buf = g_read_data(cp, off, sectorsize, &error);
  361                         if (buf == NULL || error != 0)
  362                                 break;
  363                         if (buf[0x1fe] != 0x55 && buf[0x1ff] != 0xaa) {
  364                                 g_free(buf);
  365                                 break;
  366                         }
  367                         for (i = 0; i < NDOSPART; i++) 
  368                                 dos_partition_dec(
  369                                     buf + DOSPARTOFF + 
  370                                     i * sizeof(struct dos_partition), dp + i);
  371                         g_free(buf);
  372                         if (bootverbose) {
  373                                 printf("MBREXT Slice %d on %s:\n",
  374                                     slice + 5, gp->name);
  375                                 g_mbr_print(0, dp);
  376                                 g_mbr_print(1, dp + 1);
  377                         }
  378                         if ((dp[0].dp_flag & 0x7f) == 0 &&
  379                              dp[0].dp_size != 0 && dp[0].dp_typ != 0) {
  380                                 g_topology_lock();
  381                                 g_slice_config(gp, slice, G_SLICE_CONFIG_SET,
  382                                     (((off_t)dp[0].dp_start) << 9ULL) + off,
  383                                     ((off_t)dp[0].dp_size) << 9ULL,
  384                                     sectorsize,
  385                                     "%*.*s%d",
  386                                     strlen(gp->name) - 1,
  387                                     strlen(gp->name) - 1,
  388                                     gp->name,
  389                                     slice + 5);
  390                                 g_topology_unlock();
  391                                 ms->type[slice] = dp[0].dp_typ;
  392                                 slice++;
  393                         }
  394                         if (dp[1].dp_flag != 0)
  395                                 break;
  396                         if (dp[1].dp_typ != DOSPTYP_EXT &&
  397                             dp[1].dp_typ != DOSPTYP_EXTLBA)
  398                                 break;
  399                         if (dp[1].dp_size == 0)
  400                                 break;
  401                         off = ((off_t)dp[1].dp_start) << 9ULL;
  402                 }
  403                 break;
  404         } while (0);
  405         g_topology_lock();
  406         g_access_rel(cp, -1, 0, 0);
  407         if (LIST_EMPTY(&gp->provider)) {
  408                 g_slice_spoiled(cp);
  409                 return (NULL);
  410         }
  411         return (gp);
  412 }
  413 
  414 
  415 static struct g_class g_mbrext_class    = {
  416         .name = MBREXT_CLASS_NAME,
  417         .taste = g_mbrext_taste,
  418 };
  419 
  420 DECLARE_GEOM_CLASS(g_mbrext_class, g_mbrext);
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FreeBSD/Linux Kernel Cross Reference sys/geom/geom_mbr.c

FreeBSD/Linux Kernel Cross Reference
sys/geom/geom_mbr.c
