lib/libstand/hammerread.c

   1 /*
   2  * Copyright (c) 2008 The DragonFly Project.  All rights reserved.
   3  *
   4  * This code is derived from software contributed to The DragonFly Project
   5  * by Simon Schubert <corecode@fs.ei.tum.de>
   6  * and Matthew Dillon <dillon@backplane.com>
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  *
  12  * 1. Redistributions of source code must retain the above copyright
  13  *    notice, this list of conditions and the following disclaimer.
  14  * 2. Redistributions in binary form must reproduce the above copyright
  15  *    notice, this list of conditions and the following disclaimer in
  16  *    the documentation and/or other materials provided with the
  17  *    distribution.
  18  * 3. Neither the name of The DragonFly Project nor the names of its
  19  *    contributors may be used to endorse or promote products derived
  20  *    from this software without specific, prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  23  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  24  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  25  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  26  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  27  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  28  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  29  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  30  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  31  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  32  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  33  * SUCH DAMAGE.
  34  *
  35  * $DragonFly: src/lib/libstand/hammerread.c,v 1.2 2008/10/29 22:14:25 swildner Exp $
  36  */
  37
  38 /*
  39  * This file is being used by boot2 and libstand (loader).
  40  * Compile with -DTESTING to obtain a binary.
  41  */
  42
  43
  44 #if !defined(BOOT2) && !defined(TESTING)
  45 #define LIBSTAND        1
  46 #endif
  47
  48 #include <sys/param.h>
  49
  50 #include <stddef.h>
  51 #include <stdint.h>
  52
  53 #ifdef TESTING
  54 #include <sys/fcntl.h>
  55 #include <sys/stat.h>
  56 #include <unistd.h>
  57 #include <err.h>
  58 #include <stdio.h>
  59 #include <stdlib.h>
  60 #include <string.h>
  61 #include <errno.h>
  62 #include <dirent.h>
  63 #endif
  64
  65 #ifdef LIBSTAND
  66 #include "stand.h"
  67 #endif
  68
  69 #include <vfs/hammer/hammer_disk.h>
  70
  71 #ifndef BOOT2
  72 struct blockentry {
  73         hammer_off_t    off;
  74         int             use;
  75         char            *data;
  76 };
  77
  78 #ifdef TESTING
  79 #define NUMCACHE        16
  80 #else
  81 #define NUMCACHE        6
  82 #endif
  83
  84 struct hfs {
  85 #ifdef TESTING
  86         int             fd;
  87 #else   // libstand
  88         struct open_file *f;
  89 #endif
  90         hammer_off_t    root;
  91         int64_t         buf_beg;
  92         int             lru;
  93         struct blockentry cache[NUMCACHE];
  94 };
  95
  96 static void *
  97 hread(struct hfs *hfs, hammer_off_t off)
  98 {
  99         hammer_off_t boff = off & ~HAMMER_BUFMASK64;
 100
 101         boff &= HAMMER_OFF_LONG_MASK;
 102
 103         if (HAMMER_ZONE_DECODE(off) != HAMMER_ZONE_RAW_VOLUME_INDEX)
 104                 boff += hfs->buf_beg;
 105
 106         struct blockentry *be = NULL;
 107         for (int i = 0; i < NUMCACHE; i++) {
 108                 if (be == NULL || be->use > hfs->cache[i].use)
 109                         be = &hfs->cache[i];
 110                 if (hfs->cache[i].off == boff) {
 111                         be = &hfs->cache[i];
 112                         break;
 113                 }
 114         }
 115         if (be->off != boff) {
 116                 // Didn't find any match
 117                 be->off = boff;
 118 #ifdef TESTING
 119                 ssize_t res = pread(hfs->fd, be->data, HAMMER_BUFSIZE,
 120                                     boff & HAMMER_OFF_SHORT_MASK);
 121                 if (res != HAMMER_BUFSIZE)
 122                         err(1, "short read on off %llx", boff);
 123 #else   // libstand
 124                 size_t rlen;
 125                 int rv = hfs->f->f_dev->dv_strategy(hfs->f->f_devdata, F_READ,
 126                         boff >> DEV_BSHIFT, HAMMER_BUFSIZE,
 127                         be->data, &rlen);
 128                 if (rv || rlen != HAMMER_BUFSIZE)
 129                         return (NULL);
 130 #endif
 131         }
 132
 133         be->use = ++hfs->lru;
 134         return &be->data[off & HAMMER_BUFMASK];
 135 }
 136
 137 #else   /* BOOT2 */
 138
 139 struct dmadat {
 140         char            secbuf[DEV_BSIZE];
 141         char            buf[HAMMER_BUFSIZE];
 142 };
 143
 144 static struct dmadat *dmadat;
 145
 146 struct hfs {
 147         hammer_off_t    root;
 148         int64_t         buf_beg;
 149 };
 150
 151 static void *
 152 hread(struct hfs *hfs, hammer_off_t off)
 153 {
 154         char *buf = dmadat->buf;
 155
 156         hammer_off_t boff = off & ~HAMMER_BUFMASK64;
 157         boff &= HAMMER_OFF_LONG_MASK;
 158         if (HAMMER_ZONE_DECODE(off) != HAMMER_ZONE_RAW_VOLUME_INDEX)
 159                 boff += hfs->buf_beg;
 160         boff &= HAMMER_OFF_SHORT_MASK;
 161         boff >>= DEV_BSHIFT;
 162         if (dskread(buf, boff, HAMMER_BUFSIZE >> DEV_BSHIFT))
 163                 return (NULL);
 164         return (&buf[off & HAMMER_BUFMASK]);
 165 }
 166
 167 static void
 168 bzero(void *buf, size_t size)
 169 {
 170         for (size_t i = 0; i < size; i++)
 171                 ((char *)buf)[i] = 0;
 172 }
 173
 174 static void
 175 bcopy(void *src, void *dst, size_t size)
 176 {
 177         memcpy(dst, src, size);
 178 }
 179
 180 static size_t
 181 strlen(const char *s)
 182 {
 183         size_t l = 0;
 184         for (; *s != 0; s++)
 185                 l++;
 186         return (l);
 187 }
 188
 189 static int
 190 memcmp(const void *a, const void *b, size_t len)
 191 {
 192         for (size_t p = 0; p < len; p++) {
 193                 int r = ((const char *)a)[p] - ((const char *)b)[p];
 194                 if (r != 0)
 195                         return (r);
 196         }
 197
 198         return (0);
 199 }
 200
 201 #endif
 202
 203 /*
 204  * (from hammer_btree.c)
 205  *
 206  * Compare two B-Tree elements, return -N, 0, or +N (e.g. similar to strcmp).
 207  *
 208  * Note that for this particular function a return value of -1, 0, or +1
 209  * can denote a match if create_tid is otherwise discounted.  A create_tid
 210  * of zero is considered to be 'infinity' in comparisons.
 211  *
 212  * See also hammer_rec_rb_compare() and hammer_rec_cmp() in hammer_object.c.
 213  */
 214 static int
 215 hammer_btree_cmp(hammer_base_elm_t key1, hammer_base_elm_t key2)
 216 {
 217         if (key1->localization < key2->localization)
 218                 return(-5);
 219         if (key1->localization > key2->localization)
 220                 return(5);
 221
 222         if (key1->obj_id < key2->obj_id)
 223                 return(-4);
 224         if (key1->obj_id > key2->obj_id)
 225                 return(4);
 226
 227         if (key1->rec_type < key2->rec_type)
 228                 return(-3);
 229         if (key1->rec_type > key2->rec_type)
 230                 return(3);
 231
 232         if (key1->key < key2->key)
 233                 return(-2);
 234         if (key1->key > key2->key)
 235                 return(2);
 236
 237         /*
 238          * A create_tid of zero indicates a record which is undeletable
 239          * and must be considered to have a value of positive infinity.
 240          */
 241         if (key1->create_tid == 0) {
 242                 if (key2->create_tid == 0)
 243                         return(0);
 244                 return(1);
 245         }
 246         if (key2->create_tid == 0)
 247                 return(-1);
 248         if (key1->create_tid < key2->create_tid)
 249                 return(-1);
 250         if (key1->create_tid > key2->create_tid)
 251                 return(1);
 252         return(0);
 253 }
 254
 255 /*
 256  * Heuristical search for the first element whos comparison is <= 1.  May
 257  * return an index whos compare result is > 1 but may only return an index
 258  * whos compare result is <= 1 if it is the first element with that result.
 259  */
 260 static int
 261 hammer_btree_search_node(hammer_base_elm_t elm, hammer_node_ondisk_t node)
 262 {
 263         int b;
 264         int s;
 265         int i;
 266         int r;
 267
 268         /*
 269          * Don't bother if the node does not have very many elements
 270          */
 271         b = 0;
 272         s = node->count;
 273         while (s - b > 4) {
 274                 i = b + (s - b) / 2;
 275                 r = hammer_btree_cmp(elm, &node->elms[i].leaf.base);
 276                 if (r <= 1) {
 277                         s = i;
 278                 } else {
 279                         b = i;
 280                 }
 281         }
 282         return(b);
 283 }
 284
 285 #if 0
 286 /*
 287  * (from hammer_subs.c)
 288  *
 289  * Return a namekey hash.   The 64 bit namekey hash consists of a 32 bit
 290  * crc in the MSB and 0 in the LSB.  The caller will use the low bits to
 291  * generate a unique key and will scan all entries with the same upper
 292  * 32 bits when issuing a lookup.
 293  *
 294  * We strip bit 63 in order to provide a positive key, this way a seek
 295  * offset of 0 will represent the base of the directory.
 296  *
 297  * This function can never return 0.  We use the MSB-0 space to synthesize
 298  * artificial directory entries such as "." and "..".
 299  */
 300 static int64_t
 301 hammer_directory_namekey(const void *name, int len)
 302 {
 303         int64_t key;
 304
 305         key = (int64_t)(crc32(name, len) & 0x7FFFFFFF) << 32;
 306         if (key == 0)
 307                 key |= 0x100000000LL;
 308         return(key);
 309 }
 310 #else
 311 static int64_t
 312 hammer_directory_namekey(const void *name __unused, int len __unused)
 313 {
 314         return (0);
 315 }
 316 #endif
 317
 318
 319 #ifndef BOOT2
 320 /*
 321  * Misc
 322  */
 323 static u_int32_t
 324 hammer_to_unix_xid(uuid_t *uuid)
 325 {
 326         return(*(u_int32_t *)&uuid->node[2]);
 327 }
 328
 329 static int
 330 hammer_get_dtype(u_int8_t obj_type)
 331 {
 332         switch(obj_type) {
 333         case HAMMER_OBJTYPE_DIRECTORY:
 334                 return(DT_DIR);
 335         case HAMMER_OBJTYPE_REGFILE:
 336                 return(DT_REG);
 337         case HAMMER_OBJTYPE_DBFILE:
 338                 return(DT_DBF);
 339         case HAMMER_OBJTYPE_FIFO:
 340                 return(DT_FIFO);
 341         case HAMMER_OBJTYPE_SOCKET:
 342                 return(DT_SOCK);
 343         case HAMMER_OBJTYPE_CDEV:
 344                 return(DT_CHR);
 345         case HAMMER_OBJTYPE_BDEV:
 346                 return(DT_BLK);
 347         case HAMMER_OBJTYPE_SOFTLINK:
 348                 return(DT_LNK);
 349         default:
 350                 return(DT_UNKNOWN);
 351         }
 352         /* not reached */
 353 }
 354
 355 static int
 356 hammer_get_mode(u_int8_t obj_type)
 357 {
 358         switch(obj_type) {
 359         case HAMMER_OBJTYPE_DIRECTORY:
 360                 return(S_IFDIR);
 361         case HAMMER_OBJTYPE_REGFILE:
 362                 return(S_IFREG);
 363         case HAMMER_OBJTYPE_DBFILE:
 364                 return(S_IFDB);
 365         case HAMMER_OBJTYPE_FIFO:
 366                 return(S_IFIFO);
 367         case HAMMER_OBJTYPE_SOCKET:
 368                 return(S_IFSOCK);
 369         case HAMMER_OBJTYPE_CDEV:
 370                 return(S_IFCHR);
 371         case HAMMER_OBJTYPE_BDEV:
 372                 return(S_IFBLK);
 373         case HAMMER_OBJTYPE_SOFTLINK:
 374                 return(S_IFLNK);
 375         default:
 376                 return(0);
 377         }
 378         /* not reached */
 379 }
 380
 381 #if DEBUG > 1
 382 static void
 383 hprintb(hammer_base_elm_t e)
 384 {
 385         printf("%d/", e->localization);
 386         if (e->obj_id >> 32 != 0)
 387                 printf("%lx%08lx",
 388                        (long)(e->obj_id >> 32),
 389                        (long)(e->obj_id & 0xffffffff));
 390         else
 391                 printf("%lx", (long)e->obj_id);
 392         printf("/%d/", e->rec_type);
 393         if (e->key >> 32 != 0)
 394                 printf("%lx%08lx",
 395                        (long)(e->key >> 32),
 396                        (long)(e->key & 0xffffffff));
 397         else
 398                 printf("%lx", (long)e->key);
 399 #ifdef TESTING
 400         printf("/%llx/%llx", e->create_tid, e->delete_tid);
 401 #endif
 402 }
 403 #endif /* DEBUG > 1 */
 404 #endif /* !BOOT2 */
 405
 406 static hammer_btree_leaf_elm_t
 407 hfind(struct hfs *hfs, hammer_base_elm_t key, hammer_base_elm_t end)
 408 {
 409 #if DEBUG > 1
 410         printf("searching for ");
 411         hprintb(key);
 412         printf(" end ");
 413         hprintb(end);
 414         printf("\n");
 415 #endif
 416
 417         int n;
 418         int r;
 419         struct hammer_base_elm search = *key;
 420         struct hammer_base_elm backtrack;
 421         hammer_off_t nodeoff = hfs->root;
 422         hammer_node_ondisk_t node;
 423         hammer_btree_elm_t e = NULL;
 424
 425 loop:
 426         node = hread(hfs, nodeoff);
 427         if (node == NULL)
 428                 return (NULL);
 429
 430 #if DEBUG > 3
 431         for (int i = 0; i < node->count; i++) {
 432                 printf("E: ");
 433                 hprintb(&node->elms[i].base);
 434                 printf("\n");
 435         }
 436 #endif
 437
 438         n = hammer_btree_search_node(&search, node);
 439
 440         for (; n < node->count; n++) {
 441                 e = &node->elms[n];
 442                 r = hammer_btree_cmp(&search, &e->base);
 443
 444                 if (r < 0)
 445                         break;
 446         }
 447
 448         // unless we stopped right on the left side, we need to back off a bit
 449         if (n > 0)
 450                 e = &node->elms[n - 1];
 451
 452 #if DEBUG > 2
 453         printf("  found: ");
 454         hprintb(&e->base);
 455         printf("\n");
 456 #endif
 457
 458         if (node->type == HAMMER_BTREE_TYPE_INTERNAL) {
 459                 nodeoff = e->internal.subtree_offset;
 460                 backtrack = (e+1)->base;
 461                 goto loop;
 462         }
 463
 464         r = hammer_btree_cmp(key, &e->base);
 465         // If we're more off than the createtid, take the next elem
 466         if (r > 1) {
 467                 e++;
 468                 n++;
 469         }
 470
 471         // Skip deleted elements
 472         while (n <= node->count && e->base.delete_tid != 0) {
 473                 e++;
 474                 n++;
 475         }
 476
 477         // In the unfortunate event when there is no next
 478         // element in this node, we repeat the search with
 479         // a key beyond the right boundary
 480         if (n > node->count) {
 481                 search = backtrack;
 482                 nodeoff = hfs->root;
 483
 484 #if DEBUG > 2
 485                 printf("hit right boundary (%d), resetting search to ",
 486                        node->count);
 487                 hprintb(&search);
 488                 printf("\n");
 489 #endif
 490                 goto loop;
 491         }
 492
 493 #if DEBUG > 1
 494         printf("  result: ");
 495         hprintb(&e->base);
 496         printf("\n");
 497 #endif
 498
 499         if (end != NULL)
 500                 if (hammer_btree_cmp(end, &e->base) < -1)
 501                         goto fail;
 502
 503         return (&e->leaf);
 504
 505 fail:
 506 #if DEBUG > 1
 507         printf("  fail.\n");
 508 #endif
 509         return (NULL);
 510 }
 511
 512 #ifndef BOOT2
 513 static int
 514 hreaddir(struct hfs *hfs, ino_t ino, int64_t *off, struct dirent *de)
 515 {
 516         struct hammer_base_elm key, end;
 517
 518 #if DEBUG > 2
 519         printf("%s(%llx, %lld)\n", __FUNCTION__, (long long)ino, *off);
 520 #endif
 521
 522         bzero(&key, sizeof(key));
 523         key.obj_id = ino;
 524         key.localization = HAMMER_LOCALIZE_MISC;
 525         key.rec_type = HAMMER_RECTYPE_DIRENTRY;
 526         key.key = *off;
 527
 528         end = key;
 529         end.key = HAMMER_MAX_KEY;
 530
 531         hammer_btree_leaf_elm_t e;
 532
 533         e = hfind(hfs, &key, &end);
 534         if (e == NULL) {
 535                 errno = ENOENT;
 536                 return (-1);
 537         }
 538
 539         *off = e->base.key + 1;         // remember next pos
 540
 541         de->d_namlen = e->data_len - HAMMER_ENTRY_NAME_OFF;
 542         de->d_type = hammer_get_dtype(e->base.obj_type);
 543         hammer_data_ondisk_t ed = hread(hfs, e->data_offset);
 544         if (ed == NULL)
 545                 return (-1);
 546         de->d_ino = ed->entry.obj_id;
 547         bcopy(ed->entry.name, de->d_name, de->d_namlen);
 548         de->d_name[de->d_namlen] = 0;
 549
 550         return (0);
 551 }
 552 #endif
 553
 554 static ino_t
 555 hresolve(struct hfs *hfs, ino_t dirino, const char *name)
 556 {
 557         struct hammer_base_elm key, end;
 558         size_t namel = strlen(name);
 559
 560 #if DEBUG > 2
 561         printf("%s(%llx, %s)\n", __FUNCTION__, (long long)dirino, name);
 562 #endif
 563
 564         bzero(&key, sizeof(key));
 565         key.obj_id = dirino;
 566         key.localization = HAMMER_LOCALIZE_MISC;
 567         key.key = hammer_directory_namekey(name, namel);
 568         key.rec_type = HAMMER_RECTYPE_DIRENTRY;
 569         end = key;
 570         end.key = HAMMER_MAX_KEY;
 571
 572         hammer_btree_leaf_elm_t e;
 573         while ((e = hfind(hfs, &key, &end)) != NULL) {
 574                 key.key = e->base.key + 1;
 575
 576                 size_t elen = e->data_len - HAMMER_ENTRY_NAME_OFF;
 577                 hammer_data_ondisk_t ed = hread(hfs, e->data_offset);
 578                 if (ed == NULL)
 579                         return (-1);
 580 #ifdef BOOT2
 581                 if (ls) {
 582                         for (int i = 0; i < elen; i++)
 583                                 putchar(ed->entry.name[i]);
 584                         putchar(' ');
 585                         ls = 2;
 586                         continue;
 587                 }
 588 #endif
 589                 if (elen == namel && memcmp(ed->entry.name, name, MIN(elen, namel)) == 0)
 590                         return (ed->entry.obj_id);
 591         }
 592
 593 #if BOOT2
 594         if (ls == 2)
 595                 printf("\n");
 596 #endif
 597
 598         return -1;
 599 }
 600
 601 static ino_t
 602 hlookup(struct hfs *hfs, const char *path)
 603 {
 604 #if DEBUG > 2
 605         printf("%s(%s)\n", __FUNCTION__, path);
 606 #endif
 607
 608 #ifdef BOOT2
 609         ls = 0;
 610 #endif
 611         ino_t ino = 1;
 612         do {
 613                 char name[MAXPATHLEN + 1];
 614                 while (*path == '/')
 615                         path++;
 616                 if (*path == 0)
 617                         break;
 618                 for (char *n = name; *path != 0 && *path != '/'; path++, n++) {
 619                         n[0] = *path;
 620                         n[1] = 0;
 621                 }
 622
 623 #ifdef BOOT2
 624                 // A single ? means "list"
 625                 if (name[0] == '?' && name[1] == 0)
 626                         ls = 1;
 627 #endif
 628
 629                 ino = hresolve(hfs, ino, name);
 630         } while (ino != (ino_t)-1 && *path != 0);
 631
 632         return (ino);
 633 }
 634
 635
 636 #ifndef BOOT2
 637 static int
 638 hstat(struct hfs *hfs, ino_t ino, struct stat* st)
 639 {
 640         struct hammer_base_elm key;
 641
 642 #if DEBUG > 2
 643         printf("%s(%llx)\n", __FUNCTION__, (long long)ino);
 644 #endif
 645
 646         bzero(&key, sizeof(key));
 647         key.obj_id = ino;
 648         key.localization = HAMMER_LOCALIZE_INODE;
 649         key.rec_type = HAMMER_RECTYPE_INODE;
 650
 651         hammer_btree_leaf_elm_t e = hfind(hfs, &key, &key);
 652         if (e == NULL) {
 653 #ifndef BOOT2
 654                 errno = ENOENT;
 655 #endif
 656                 return -1;
 657         }
 658
 659         hammer_data_ondisk_t ed = hread(hfs, e->data_offset);
 660         if (ed == NULL)
 661                 return (-1);
 662
 663         st->st_mode = ed->inode.mode | hammer_get_mode(ed->inode.obj_type);
 664         st->st_uid = hammer_to_unix_xid(&ed->inode.uid);
 665         st->st_gid = hammer_to_unix_xid(&ed->inode.gid);
 666         st->st_size = ed->inode.size;
 667
 668         return (0);
 669 }
 670 #endif
 671
 672 static ssize_t
 673 hreadf(struct hfs *hfs, ino_t ino, int64_t off, int64_t len, char *buf)
 674 {
 675         int64_t startoff = off;
 676         struct hammer_base_elm key, end;
 677
 678         bzero(&key, sizeof(key));
 679         key.obj_id = ino;
 680         key.localization = HAMMER_LOCALIZE_MISC;
 681         key.rec_type = HAMMER_RECTYPE_DATA;
 682         end = key;
 683         end.key = HAMMER_MAX_KEY;
 684
 685         while (len > 0) {
 686                 key.key = off + 1;
 687                 hammer_btree_leaf_elm_t e = hfind(hfs, &key, &end);
 688                 int64_t dlen;
 689
 690                 if (e == NULL || off > e->base.key) {
 691                         bzero(buf, len);
 692                         off += len;
 693                         len = 0;
 694                         break;
 695                 }
 696
 697                 int64_t doff = e->base.key - e->data_len;
 698                 if (off < doff) {
 699                         // sparse file, beginning
 700                         dlen = doff - off;
 701                         dlen = MIN(dlen, len);
 702                         bzero(buf, dlen);
 703                 } else {
 704                         int64_t boff = off - doff;
 705                         hammer_off_t roff = e->data_offset;
 706
 707                         dlen = e->data_len;
 708                         dlen -= boff;
 709                         dlen = MIN(dlen, len);
 710
 711                         while (boff >= HAMMER_BUFSIZE) {
 712                                 boff -= HAMMER_BUFSIZE;
 713                                 roff += HAMMER_BUFSIZE;
 714                         }
 715
 716                         /*
 717                          * boff - relative offset in disk buffer (not aligned)
 718                          * roff - base offset of disk buffer     (not aligned)
 719                          * dlen - amount of data we think we can copy
 720                          *
 721                          * hread only reads 16K aligned buffers, check for
 722                          * a length overflow and truncate dlen appropriately.
 723                          */
 724                         if ((roff & ~HAMMER_BUFMASK64) != ((roff + boff + dlen - 1) & ~HAMMER_BUFMASK64))
 725                                 dlen = HAMMER_BUFSIZE - ((boff + roff) & HAMMER_BUFMASK);
 726                         char *data = hread(hfs, roff);
 727                         if (data == NULL)
 728                                 return (-1);
 729                         bcopy(data + boff, buf, dlen);
 730                 }
 731
 732                 buf += dlen;
 733                 off += dlen;
 734                 len -= dlen;
 735         }
 736
 737         return (off - startoff);
 738 }
 739
 740 #ifdef BOOT2
 741 struct hfs hfs;
 742
 743 static int
 744 hammerinit(void)
 745 {
 746         if (dsk_meta)
 747                 return (0);
 748
 749         hammer_volume_ondisk_t volhead = hread(&hfs, HAMMER_ZONE_ENCODE(1, 0));
 750         if (volhead == NULL)
 751                 return (-1);
 752         if (volhead->vol_signature != HAMMER_FSBUF_VOLUME)
 753                 return (-1);
 754         hfs.root = volhead->vol0_btree_root;
 755         hfs.buf_beg = volhead->vol_buf_beg;
 756         dsk_meta++;
 757         return (0);
 758 }
 759
 760 static ino_t
 761 lookup(const char *path)
 762 {
 763         hammerinit();
 764
 765         ino_t ino = hlookup(&hfs, path);
 766
 767         if (ino == -1)
 768                 ino = 0;
 769         return (ino);
 770 }
 771
 772 static ssize_t
 773 fsread(ino_t ino, void *buf, size_t len)
 774 {
 775         hammerinit();
 776
 777         ssize_t rlen = hreadf(&hfs, ino, fs_off, len, buf);
 778         if (rlen != -1)
 779                 fs_off += rlen;
 780         return (rlen);
 781 }
 782 #endif
 783
 784 #ifndef BOOT2
 785 static int
 786 hinit(struct hfs *hfs)
 787 {
 788 #if DEBUG
 789         printf("hinit\n");
 790 #endif
 791         for (int i = 0; i < NUMCACHE; i++) {
 792                 hfs->cache[i].data = malloc(HAMMER_BUFSIZE);
 793                 hfs->cache[i].off = -1; // invalid
 794                 hfs->cache[i].use = 0;
 795
 796 #if DEBUG
 797                 if (hfs->cache[i].data == NULL)
 798                         printf("malloc failed\n");
 799 #endif
 800         }
 801         hfs->lru = 0;
 802
 803         hammer_volume_ondisk_t volhead = hread(hfs, HAMMER_ZONE_ENCODE(1, 0));
 804         if (volhead == NULL)
 805                 return (-1);
 806
 807 #ifdef TESTING
 808         printf("signature: %svalid\n",
 809                volhead->vol_signature != HAMMER_FSBUF_VOLUME ?
 810                         "in" :
 811                         "");
 812         printf("name: %s\n", volhead->vol_name);
 813 #endif
 814
 815         if (volhead->vol_signature != HAMMER_FSBUF_VOLUME) {
 816                 for (int i = 0; i < NUMCACHE; i++)
 817                         free(hfs->cache[i].data);
 818                 errno = ENODEV;
 819                 return (-1);
 820         }
 821
 822         hfs->root = volhead->vol0_btree_root;
 823         hfs->buf_beg = volhead->vol_buf_beg;
 824
 825         return (0);
 826 }
 827
 828 static void
 829 hclose(struct hfs *hfs)
 830 {
 831 #if DEBUG
 832         printf("hclose\n");
 833 #endif
 834         for (int i = 0; i < NUMCACHE; i++)
 835                 free(hfs->cache[i].data);
 836 }
 837 #endif
 838
 839 #ifdef LIBSTAND
 840 struct hfile {
 841         struct hfs      hfs;
 842         ino_t           ino;
 843         int64_t         fsize;
 844 };
 845
 846 static int
 847 hammer_open(const char *path, struct open_file *f)
 848 {
 849         struct hfile *hf = malloc(sizeof(*hf));
 850         bzero(hf, sizeof(*hf));
 851
 852         f->f_fsdata = hf;
 853         hf->hfs.f = f;
 854         f->f_offset = 0;
 855
 856         int rv = hinit(&hf->hfs);
 857         if (rv) {
 858                 free(hf);
 859                 return (rv);
 860         }
 861
 862 #if DEBUG
 863         printf("hammer_open %s %p %ld\n", path, f);
 864 #endif
 865
 866         hf->ino = hlookup(&hf->hfs, path);
 867         if (hf->ino == -1)
 868                 goto fail;
 869
 870         struct stat st;
 871         if (hstat(&hf->hfs, hf->ino, &st) == -1)
 872                 goto fail;
 873         hf->fsize = st.st_size;
 874
 875 #if DEBUG
 876         printf("        %ld\n", (long)hf->fsize);
 877 #endif
 878
 879         return (0);
 880
 881 fail:
 882 #if DEBUG
 883         printf("hammer_open fail\n");
 884 #endif
 885         hclose(&hf->hfs);
 886         free(hf);
 887         return (ENOENT);
 888 }
 889
 890 static int
 891 hammer_close(struct open_file *f)
 892 {
 893         struct hfile *hf = f->f_fsdata;
 894
 895         hclose(&hf->hfs);
 896         f->f_fsdata = NULL;
 897         free(hf);
 898         return (0);
 899 }
 900
 901 static int
 902 hammer_read(struct open_file *f, void *buf, size_t len, size_t *resid)
 903 {
 904         struct hfile *hf = f->f_fsdata;
 905
 906 #if DEBUG
 907         printf("hammer_read %p %ld %ld\n", f, f->f_offset, len);
 908 #endif
 909
 910         if (f->f_offset >= hf->fsize)
 911                 return (EINVAL);
 912
 913         size_t maxlen = len;
 914         if (f->f_offset + len > hf->fsize)
 915                 maxlen = hf->fsize - f->f_offset;
 916
 917         ssize_t rlen = hreadf(&hf->hfs, hf->ino, f->f_offset, maxlen, buf);
 918         if (rlen == -1)
 919                 return (EINVAL);
 920
 921         f->f_offset += rlen;
 922
 923         *resid = len - rlen;
 924         return (0);
 925 }
 926
 927 static off_t
 928 hammer_seek(struct open_file *f, off_t offset, int whence)
 929 {
 930         struct hfile *hf = f->f_fsdata;
 931
 932         switch (whence) {
 933         case SEEK_SET:
 934                 f->f_offset = offset;
 935                 break;
 936         case SEEK_CUR:
 937                 f->f_offset += offset;
 938                 break;
 939         case SEEK_END:
 940                 f->f_offset = hf->fsize - offset;
 941                 break;
 942         default:
 943                 return (-1);
 944         }
 945         return (f->f_offset);
 946 }
 947
 948 static int
 949 hammer_stat(struct open_file *f, struct stat *st)
 950 {
 951         struct hfile *hf = f->f_fsdata;
 952
 953         return (hstat(&hf->hfs, hf->ino, st));
 954 }
 955
 956 static int
 957 hammer_readdir(struct open_file *f, struct dirent *d)
 958 {
 959         struct hfile *hf = f->f_fsdata;
 960
 961         int64_t off = f->f_offset;
 962         int rv = hreaddir(&hf->hfs, hf->ino, &off, d);
 963         f->f_offset = off;
 964         return (rv);
 965 }
 966
 967 // libstand
 968 struct fs_ops hammer_fsops = {
 969         "hammer",
 970         hammer_open,
 971         hammer_close,
 972         hammer_read,
 973         null_write,
 974         hammer_seek,
 975         hammer_stat,
 976         hammer_readdir
 977 };
 978 #endif  // LIBSTAND
 979
 980 #ifdef TESTING
 981 int
 982 main(int argc, char **argv)
 983 {
 984         if (argc < 2) {
 985                 fprintf(stderr, "usage: hammerread <dev>\n");
 986                 return (1);
 987         }
 988
 989         struct hfs hfs;
 990         hfs.fd = open(argv[1], O_RDONLY);
 991         if (hfs.fd == -1)
 992                 err(1, "unable to open %s", argv[1]);
 993
 994         if (hinit(&hfs) == -1)
 995                 err(1, "invalid hammerfs");
 996
 997         for (int i = 2; i < argc; i++) {
 998                 ino_t ino = hlookup(&hfs, argv[i]);
 999                 if (ino == (ino_t)-1) {
1000                         warn("hlookup %s", argv[i]);
1001                         continue;
1002                 }
1003
1004                 struct stat st;
1005                 if (hstat(&hfs, ino, &st)) {
1006                         warn("hstat %s", argv[i]);
1007                         continue;
1008                 }
1009
1010                 printf("%s %d/%d %o %lld\n",
1011                        argv[i],
1012                        st.st_uid, st.st_gid,
1013                        st.st_mode, st.st_size);
1014
1015                 if (S_ISDIR(st.st_mode)) {
1016                         int64_t off = 0;
1017                         struct dirent de;
1018                         while (hreaddir(&hfs, ino, &off, &de) == 0) {
1019                                 printf("%s %d %llx\n",
1020                                        de.d_name, de.d_type, de.d_ino);
1021                         }
1022                 } else if (S_ISREG(st.st_mode)) {
1023                         char *buf = malloc(100000);
1024                         int64_t off = 0;
1025                         while (off < st.st_size) {
1026                                 int64_t len = MIN(100000, st.st_size - off);
1027                                 int64_t rl = hreadf(&hfs, ino, off, len, buf);
1028                                 fwrite(buf, rl, 1, stdout);
1029                                 off += rl;
1030                         }
1031                         free(buf);
1032                 }
1033         }
1034
1035         return 0;
1036 }
1037 #endif