sys/boot/common/gpt.c

   1 /*-
   2  * Copyright (c) 2010 Pawel Jakub Dawidek <pjd@FreeBSD.org>
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
  15  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  16  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  17  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE
  18  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  19  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  20  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  21  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  22  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  23  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  24  * SUCH DAMAGE.
  25  */
  26
  27 #include <sys/cdefs.h>
  28 __FBSDID("$FreeBSD$");
  29
  30 #include <sys/param.h>
  31 #include <sys/gpt.h>
  32
  33 #ifndef LITTLE_ENDIAN
  34 #error gpt.c works only for little endian architectures
  35 #endif
  36
  37 #include "crc32.h"
  38 #include "drv.h"
  39 #include "util.h"
  40 #include "gpt.h"
  41
  42 #define MAXTBLENTS      128
  43
  44 static struct gpt_hdr hdr_primary, hdr_backup, *gpthdr;
  45 static uint64_t hdr_primary_lba, hdr_backup_lba;
  46 static struct gpt_ent table_primary[MAXTBLENTS], table_backup[MAXTBLENTS];
  47 static struct gpt_ent *gpttable;
  48 static int curent, bootonce;
  49
  50 /*
  51  * Buffer below 64kB passed on gptread(), which can hold at least
  52  * one sector of data (512 bytes).
  53  */
  54 static char *secbuf;
  55
  56 static void
  57 gptupdate(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
  58     struct gpt_ent *table)
  59 {
  60         int entries_per_sec, firstent;
  61         daddr_t slba;
  62
  63         /*
  64          * We need to update the following for both primary and backup GPT:
  65          * 1. Sector on disk that contains current partition.
  66          * 2. Partition table checksum.
  67          * 3. Header checksum.
  68          * 4. Header on disk.
  69          */
  70
  71         entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
  72         slba = curent / entries_per_sec;
  73         firstent = slba * entries_per_sec;
  74         bcopy(&table[firstent], secbuf, DEV_BSIZE);
  75         slba += hdr->hdr_lba_table;
  76         if (drvwrite(dskp, secbuf, slba, 1)) {
  77                 printf("%s: unable to update %s GPT partition table\n",
  78                     BOOTPROG, which);
  79                 return;
  80         }
  81         hdr->hdr_crc_table = crc32(table, hdr->hdr_entries * hdr->hdr_entsz);
  82         hdr->hdr_crc_self = 0;
  83         hdr->hdr_crc_self = crc32(hdr, hdr->hdr_size);
  84         bzero(secbuf, DEV_BSIZE);
  85         bcopy(hdr, secbuf, hdr->hdr_size);
  86         if (drvwrite(dskp, secbuf, hdr->hdr_lba_self, 1)) {
  87                 printf("%s: unable to update %s GPT header\n", BOOTPROG, which);
  88                 return;
  89         }
  90 }
  91
  92 int
  93 gptfind(const uuid_t *uuid, struct dsk *dskp, int part)
  94 {
  95         struct gpt_ent *ent;
  96         int firsttry;
  97
  98         if (part >= 0) {
  99                 if (part == 0 || part > gpthdr->hdr_entries) {
 100                         printf("%s: invalid partition index\n", BOOTPROG);
 101                         return (-1);
 102                 }
 103                 ent = &gpttable[part - 1];
 104                 if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0) {
 105                         printf("%s: specified partition is not UFS\n",
 106                             BOOTPROG);
 107                         return (-1);
 108                 }
 109                 curent = part - 1;
 110                 goto found;
 111         }
 112
 113         firsttry = (curent == -1);
 114         curent++;
 115         if (curent >= gpthdr->hdr_entries) {
 116                 curent = gpthdr->hdr_entries;
 117                 return (-1);
 118         }
 119         if (bootonce) {
 120                 /*
 121                  * First look for partition with both GPT_ENT_ATTR_BOOTME and
 122                  * GPT_ENT_ATTR_BOOTONCE flags.
 123                  */
 124                 for (; curent < gpthdr->hdr_entries; curent++) {
 125                         ent = &gpttable[curent];
 126                         if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
 127                                 continue;
 128                         if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTME))
 129                                 continue;
 130                         if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTONCE))
 131                                 continue;
 132                         /* Ok, found one. */
 133                         goto found;
 134                 }
 135                 bootonce = 0;
 136                 curent = 0;
 137         }
 138         for (; curent < gpthdr->hdr_entries; curent++) {
 139                 ent = &gpttable[curent];
 140                 if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
 141                         continue;
 142                 if (!(ent->ent_attr & GPT_ENT_ATTR_BOOTME))
 143                         continue;
 144                 if (ent->ent_attr & GPT_ENT_ATTR_BOOTONCE)
 145                         continue;
 146                 /* Ok, found one. */
 147                 goto found;
 148         }
 149         if (firsttry) {
 150                 /*
 151                  * No partition with BOOTME flag was found, try to boot from
 152                  * first UFS partition.
 153                  */
 154                 for (curent = 0; curent < gpthdr->hdr_entries; curent++) {
 155                         ent = &gpttable[curent];
 156                         if (bcmp(&ent->ent_type, uuid, sizeof(uuid_t)) != 0)
 157                                 continue;
 158                         /* Ok, found one. */
 159                         goto found;
 160                 }
 161         }
 162         return (-1);
 163 found:
 164         dskp->part = curent + 1;
 165         ent = &gpttable[curent];
 166         dskp->start = ent->ent_lba_start;
 167         if (ent->ent_attr & GPT_ENT_ATTR_BOOTONCE) {
 168                 /*
 169                  * Clear BOOTME, but leave BOOTONCE set before trying to
 170                  * boot from this partition.
 171                  */
 172                 if (hdr_primary_lba > 0) {
 173                         table_primary[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTME;
 174                         gptupdate("primary", dskp, &hdr_primary, table_primary);
 175                 }
 176                 if (hdr_backup_lba > 0) {
 177                         table_backup[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTME;
 178                         gptupdate("backup", dskp, &hdr_backup, table_backup);
 179                 }
 180         }
 181         return (0);
 182 }
 183
 184 static int
 185 gptread_hdr(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
 186     uint64_t hdrlba)
 187 {
 188         uint32_t crc;
 189
 190         if (drvread(dskp, secbuf, hdrlba, 1)) {
 191                 printf("%s: unable to read %s GPT header\n", BOOTPROG, which);
 192                 return (-1);
 193         }
 194         bcopy(secbuf, hdr, sizeof(*hdr));
 195         if (bcmp(hdr->hdr_sig, GPT_HDR_SIG, sizeof(hdr->hdr_sig)) != 0 ||
 196             hdr->hdr_lba_self != hdrlba || hdr->hdr_revision < 0x00010000 ||
 197             hdr->hdr_entsz < sizeof(struct gpt_ent) ||
 198             hdr->hdr_entries > MAXTBLENTS || DEV_BSIZE % hdr->hdr_entsz != 0) {
 199                 printf("%s: invalid %s GPT header\n", BOOTPROG, which);
 200                 return (-1);
 201         }
 202         crc = hdr->hdr_crc_self;
 203         hdr->hdr_crc_self = 0;
 204         if (crc32(hdr, hdr->hdr_size) != crc) {
 205                 printf("%s: %s GPT header checksum mismatch\n", BOOTPROG,
 206                     which);
 207                 return (-1);
 208         }
 209         hdr->hdr_crc_self = crc;
 210         return (0);
 211 }
 212
 213 void
 214 gptbootfailed(struct dsk *dskp)
 215 {
 216
 217         if (!(gpttable[curent].ent_attr & GPT_ENT_ATTR_BOOTONCE))
 218                 return;
 219
 220         if (hdr_primary_lba > 0) {
 221                 table_primary[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
 222                 table_primary[curent].ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
 223                 gptupdate("primary", dskp, &hdr_primary, table_primary);
 224         }
 225         if (hdr_backup_lba > 0) {
 226                 table_backup[curent].ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
 227                 table_backup[curent].ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
 228                 gptupdate("backup", dskp, &hdr_backup, table_backup);
 229         }
 230 }
 231
 232 static void
 233 gptbootconv(const char *which, struct dsk *dskp, struct gpt_hdr *hdr,
 234     struct gpt_ent *table)
 235 {
 236         struct gpt_ent *ent;
 237         daddr_t slba;
 238         int table_updated, sector_updated;
 239         int entries_per_sec, nent, part;
 240
 241         table_updated = 0;
 242         entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
 243         for (nent = 0, slba = hdr->hdr_lba_table;
 244              slba < hdr->hdr_lba_table + hdr->hdr_entries / entries_per_sec;
 245              slba++, nent += entries_per_sec) {
 246                 sector_updated = 0;
 247                 for (part = 0; part < entries_per_sec; part++) {
 248                         ent = &table[nent + part];
 249                         if ((ent->ent_attr & (GPT_ENT_ATTR_BOOTME |
 250                             GPT_ENT_ATTR_BOOTONCE |
 251                             GPT_ENT_ATTR_BOOTFAILED)) !=
 252                             GPT_ENT_ATTR_BOOTONCE) {
 253                                 continue;
 254                         }
 255                         ent->ent_attr &= ~GPT_ENT_ATTR_BOOTONCE;
 256                         ent->ent_attr |= GPT_ENT_ATTR_BOOTFAILED;
 257                         table_updated = 1;
 258                         sector_updated = 1;
 259                 }
 260                 if (!sector_updated)
 261                         continue;
 262                 bcopy(&table[nent], secbuf, DEV_BSIZE);
 263                 if (drvwrite(dskp, secbuf, slba, 1)) {
 264                         printf("%s: unable to update %s GPT partition table\n",
 265                             BOOTPROG, which);
 266                 }
 267         }
 268         if (!table_updated)
 269                 return;
 270         hdr->hdr_crc_table = crc32(table, hdr->hdr_entries * hdr->hdr_entsz);
 271         hdr->hdr_crc_self = 0;
 272         hdr->hdr_crc_self = crc32(hdr, hdr->hdr_size);
 273         bzero(secbuf, DEV_BSIZE);
 274         bcopy(hdr, secbuf, hdr->hdr_size);
 275         if (drvwrite(dskp, secbuf, hdr->hdr_lba_self, 1))
 276                 printf("%s: unable to update %s GPT header\n", BOOTPROG, which);
 277 }
 278
 279 static int
 280 gptread_table(const char *which, const uuid_t *uuid, struct dsk *dskp,
 281     struct gpt_hdr *hdr, struct gpt_ent *table)
 282 {
 283         struct gpt_ent *ent;
 284         int entries_per_sec;
 285         int part, nent;
 286         daddr_t slba;
 287
 288         if (hdr->hdr_entries == 0)
 289                 return (0);
 290
 291         entries_per_sec = DEV_BSIZE / hdr->hdr_entsz;
 292         slba = hdr->hdr_lba_table;
 293         nent = 0;
 294         for (;;) {
 295                 if (drvread(dskp, secbuf, slba, 1)) {
 296                         printf("%s: unable to read %s GPT partition table\n",
 297                             BOOTPROG, which);
 298                         return (-1);
 299                 }
 300                 ent = (struct gpt_ent *)secbuf;
 301                 for (part = 0; part < entries_per_sec; part++, ent++) {
 302                         bcopy(ent, &table[nent], sizeof(table[nent]));
 303                         if (++nent >= hdr->hdr_entries)
 304                                 break;
 305                 }
 306                 if (nent >= hdr->hdr_entries)
 307                         break;
 308                 slba++;
 309         }
 310         if (crc32(table, nent * hdr->hdr_entsz) != hdr->hdr_crc_table) {
 311                 printf("%s: %s GPT table checksum mismatch\n", BOOTPROG, which);
 312                 return (-1);
 313         }
 314         return (0);
 315 }
 316
 317 int
 318 gptread(const uuid_t *uuid, struct dsk *dskp, char *buf)
 319 {
 320         uint64_t altlba;
 321
 322         /*
 323          * Read and verify both GPT headers: primary and backup.
 324          */
 325
 326         secbuf = buf;
 327         hdr_primary_lba = hdr_backup_lba = 0;
 328         curent = -1;
 329         bootonce = 1;
 330         dskp->start = 0;
 331
 332         if (gptread_hdr("primary", dskp, &hdr_primary, 1) == 0 &&
 333             gptread_table("primary", uuid, dskp, &hdr_primary,
 334             table_primary) == 0) {
 335                 hdr_primary_lba = hdr_primary.hdr_lba_self;
 336                 gpthdr = &hdr_primary;
 337                 gpttable = table_primary;
 338         }
 339
 340         if (hdr_primary_lba > 0) {
 341                 /*
 342                  * If primary header is valid, we can get backup
 343                  * header location from there.
 344                  */
 345                 altlba = hdr_primary.hdr_lba_alt;
 346         } else {
 347                 altlba = drvsize(dskp);
 348                 if (altlba > 0)
 349                         altlba--;
 350         }
 351         if (altlba == 0)
 352                 printf("%s: unable to locate backup GPT header\n", BOOTPROG);
 353         else if (gptread_hdr("backup", dskp, &hdr_backup, altlba) == 0 &&
 354             gptread_table("backup", uuid, dskp, &hdr_backup,
 355             table_backup) == 0) {
 356                 hdr_backup_lba = hdr_backup.hdr_lba_self;
 357                 if (hdr_primary_lba == 0) {
 358                         gpthdr = &hdr_backup;
 359                         gpttable = table_backup;
 360                         printf("%s: using backup GPT\n", BOOTPROG);
 361                 }
 362         }
 363
 364         /*
 365          * Convert all BOOTONCE without BOOTME flags into BOOTFAILED.
 366          * BOOTONCE without BOOTME means that we tried to boot from it,
 367          * but failed after leaving gptboot and machine was rebooted.
 368          * We don't want to leave partitions marked as BOOTONCE only,
 369          * because when we boot successfully start-up scripts should
 370          * find at most one partition with only BOOTONCE flag and this
 371          * will mean that we booted from that partition.
 372          */
 373         if (hdr_primary_lba != 0)
 374                 gptbootconv("primary", dskp, &hdr_primary, table_primary);
 375         if (hdr_backup_lba != 0)
 376                 gptbootconv("backup", dskp, &hdr_backup, table_backup);
 377
 378         if (hdr_primary_lba == 0 && hdr_backup_lba == 0)
 379                 return (-1);
 380         return (0);
 381 }