fs/xfs/xfs_attr_list.c

   1 /*
   2  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
   3  * Copyright (c) 2013 Red Hat, Inc.
   4  * All Rights Reserved.
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License as
   8  * published by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it would be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write the Free Software Foundation,
  17  * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  18  */
  19 #include "xfs.h"
  20 #include "xfs_fs.h"
  21 #include "xfs_format.h"
  22 #include "xfs_log_format.h"
  23 #include "xfs_trans_resv.h"
  24 #include "xfs_bit.h"
  25 #include "xfs_mount.h"
  26 #include "xfs_da_format.h"
  27 #include "xfs_da_btree.h"
  28 #include "xfs_inode.h"
  29 #include "xfs_trans.h"
  30 #include "xfs_inode_item.h"
  31 #include "xfs_bmap.h"
  32 #include "xfs_attr.h"
  33 #include "xfs_attr_sf.h"
  34 #include "xfs_attr_remote.h"
  35 #include "xfs_attr_leaf.h"
  36 #include "xfs_error.h"
  37 #include "xfs_trace.h"
  38 #include "xfs_buf_item.h"
  39 #include "xfs_cksum.h"
  40 #include "xfs_dir2.h"
  41
  42 STATIC int
  43 xfs_attr_shortform_compare(const void *a, const void *b)
  44 {
  45         xfs_attr_sf_sort_t *sa, *sb;
  46
  47         sa = (xfs_attr_sf_sort_t *)a;
  48         sb = (xfs_attr_sf_sort_t *)b;
  49         if (sa->hash < sb->hash) {
  50                 return -1;
  51         } else if (sa->hash > sb->hash) {
  52                 return 1;
  53         } else {
  54                 return sa->entno - sb->entno;
  55         }
  56 }
  57
  58 #define XFS_ISRESET_CURSOR(cursor) \
  59         (!((cursor)->initted) && !((cursor)->hashval) && \
  60          !((cursor)->blkno) && !((cursor)->offset))
  61 /*
  62  * Copy out entries of shortform attribute lists for attr_list().
  63  * Shortform attribute lists are not stored in hashval sorted order.
  64  * If the output buffer is not large enough to hold them all, then we
  65  * we have to calculate each entries' hashvalue and sort them before
  66  * we can begin returning them to the user.
  67  */
  68 static int
  69 xfs_attr_shortform_list(xfs_attr_list_context_t *context)
  70 {
  71         attrlist_cursor_kern_t *cursor;
  72         xfs_attr_sf_sort_t *sbuf, *sbp;
  73         xfs_attr_shortform_t *sf;
  74         xfs_attr_sf_entry_t *sfe;
  75         xfs_inode_t *dp;
  76         int sbsize, nsbuf, count, i;
  77
  78         ASSERT(context != NULL);
  79         dp = context->dp;
  80         ASSERT(dp != NULL);
  81         ASSERT(dp->i_afp != NULL);
  82         sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
  83         ASSERT(sf != NULL);
  84         if (!sf->hdr.count)
  85                 return 0;
  86         cursor = context->cursor;
  87         ASSERT(cursor != NULL);
  88
  89         trace_xfs_attr_list_sf(context);
  90
  91         /*
  92          * If the buffer is large enough and the cursor is at the start,
  93          * do not bother with sorting since we will return everything in
  94          * one buffer and another call using the cursor won't need to be
  95          * made.
  96          * Note the generous fudge factor of 16 overhead bytes per entry.
  97          * If bufsize is zero then put_listent must be a search function
  98          * and can just scan through what we have.
  99          */
 100         if (context->bufsize == 0 ||
 101             (XFS_ISRESET_CURSOR(cursor) &&
 102              (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
 103                 for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 104                         context->put_listent(context,
 105                                              sfe->flags,
 106                                              sfe->nameval,
 107                                              (int)sfe->namelen,
 108                                              (int)sfe->valuelen);
 109                         /*
 110                          * Either search callback finished early or
 111                          * didn't fit it all in the buffer after all.
 112                          */
 113                         if (context->seen_enough)
 114                                 break;
 115                         sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 116                 }
 117                 trace_xfs_attr_list_sf_all(context);
 118                 return 0;
 119         }
 120
 121         /* do no more for a search callback */
 122         if (context->bufsize == 0)
 123                 return 0;
 124
 125         /*
 126          * It didn't all fit, so we have to sort everything on hashval.
 127          */
 128         sbsize = sf->hdr.count * sizeof(*sbuf);
 129         sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP | KM_NOFS);
 130
 131         /*
 132          * Scan the attribute list for the rest of the entries, storing
 133          * the relevant info from only those that match into a buffer.
 134          */
 135         nsbuf = 0;
 136         for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 137                 if (unlikely(
 138                     ((char *)sfe < (char *)sf) ||
 139                     ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
 140                         XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
 141                                              XFS_ERRLEVEL_LOW,
 142                                              context->dp->i_mount, sfe);
 143                         kmem_free(sbuf);
 144                         return -EFSCORRUPTED;
 145                 }
 146
 147                 sbp->entno = i;
 148                 sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
 149                 sbp->name = sfe->nameval;
 150                 sbp->namelen = sfe->namelen;
 151                 /* These are bytes, and both on-disk, don't endian-flip */
 152                 sbp->valuelen = sfe->valuelen;
 153                 sbp->flags = sfe->flags;
 154                 sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 155                 sbp++;
 156                 nsbuf++;
 157         }
 158
 159         /*
 160          * Sort the entries on hash then entno.
 161          */
 162         xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);
 163
 164         /*
 165          * Re-find our place IN THE SORTED LIST.
 166          */
 167         count = 0;
 168         cursor->initted = 1;
 169         cursor->blkno = 0;
 170         for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
 171                 if (sbp->hash == cursor->hashval) {
 172                         if (cursor->offset == count) {
 173                                 break;
 174                         }
 175                         count++;
 176                 } else if (sbp->hash > cursor->hashval) {
 177                         break;
 178                 }
 179         }
 180         if (i == nsbuf) {
 181                 kmem_free(sbuf);
 182                 return 0;
 183         }
 184
 185         /*
 186          * Loop putting entries into the user buffer.
 187          */
 188         for ( ; i < nsbuf; i++, sbp++) {
 189                 if (cursor->hashval != sbp->hash) {
 190                         cursor->hashval = sbp->hash;
 191                         cursor->offset = 0;
 192                 }
 193                 context->put_listent(context,
 194                                      sbp->flags,
 195                                      sbp->name,
 196                                      sbp->namelen,
 197                                      sbp->valuelen);
 198                 if (context->seen_enough)
 199                         break;
 200                 cursor->offset++;
 201         }
 202
 203         kmem_free(sbuf);
 204         return 0;
 205 }
 206
 207 STATIC int
 208 xfs_attr_node_list(xfs_attr_list_context_t *context)
 209 {
 210         attrlist_cursor_kern_t *cursor;
 211         xfs_attr_leafblock_t *leaf;
 212         xfs_da_intnode_t *node;
 213         struct xfs_attr3_icleaf_hdr leafhdr;
 214         struct xfs_da3_icnode_hdr nodehdr;
 215         struct xfs_da_node_entry *btree;
 216         int error, i;
 217         struct xfs_buf *bp;
 218         struct xfs_inode        *dp = context->dp;
 219         struct xfs_mount        *mp = dp->i_mount;
 220
 221         trace_xfs_attr_node_list(context);
 222
 223         cursor = context->cursor;
 224         cursor->initted = 1;
 225
 226         /*
 227          * Do all sorts of validation on the passed-in cursor structure.
 228          * If anything is amiss, ignore the cursor and look up the hashval
 229          * starting from the btree root.
 230          */
 231         bp = NULL;
 232         if (cursor->blkno > 0) {
 233                 error = xfs_da3_node_read(context->tp, dp, cursor->blkno, -1,
 234                                               &bp, XFS_ATTR_FORK);
 235                 if ((error != 0) && (error != -EFSCORRUPTED))
 236                         return error;
 237                 if (bp) {
 238                         struct xfs_attr_leaf_entry *entries;
 239
 240                         node = bp->b_addr;
 241                         switch (be16_to_cpu(node->hdr.info.magic)) {
 242                         case XFS_DA_NODE_MAGIC:
 243                         case XFS_DA3_NODE_MAGIC:
 244                                 trace_xfs_attr_list_wrong_blk(context);
 245                                 xfs_trans_brelse(context->tp, bp);
 246                                 bp = NULL;
 247                                 break;
 248                         case XFS_ATTR_LEAF_MAGIC:
 249                         case XFS_ATTR3_LEAF_MAGIC:
 250                                 leaf = bp->b_addr;
 251                                 xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo,
 252                                                              &leafhdr, leaf);
 253                                 entries = xfs_attr3_leaf_entryp(leaf);
 254                                 if (cursor->hashval > be32_to_cpu(
 255                                                 entries[leafhdr.count - 1].hashval)) {
 256                                         trace_xfs_attr_list_wrong_blk(context);
 257                                         xfs_trans_brelse(context->tp, bp);
 258                                         bp = NULL;
 259                                 } else if (cursor->hashval <= be32_to_cpu(
 260                                                 entries[0].hashval)) {
 261                                         trace_xfs_attr_list_wrong_blk(context);
 262                                         xfs_trans_brelse(context->tp, bp);
 263                                         bp = NULL;
 264                                 }
 265                                 break;
 266                         default:
 267                                 trace_xfs_attr_list_wrong_blk(context);
 268                                 xfs_trans_brelse(context->tp, bp);
 269                                 bp = NULL;
 270                         }
 271                 }
 272         }
 273
 274         /*
 275          * We did not find what we expected given the cursor's contents,
 276          * so we start from the top and work down based on the hash value.
 277          * Note that start of node block is same as start of leaf block.
 278          */
 279         if (bp == NULL) {
 280                 cursor->blkno = 0;
 281                 for (;;) {
 282                         uint16_t magic;
 283
 284                         error = xfs_da3_node_read(context->tp, dp,
 285                                                       cursor->blkno, -1, &bp,
 286                                                       XFS_ATTR_FORK);
 287                         if (error)
 288                                 return error;
 289                         node = bp->b_addr;
 290                         magic = be16_to_cpu(node->hdr.info.magic);
 291                         if (magic == XFS_ATTR_LEAF_MAGIC ||
 292                             magic == XFS_ATTR3_LEAF_MAGIC)
 293                                 break;
 294                         if (magic != XFS_DA_NODE_MAGIC &&
 295                             magic != XFS_DA3_NODE_MAGIC) {
 296                                 XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
 297                                                      XFS_ERRLEVEL_LOW,
 298                                                      context->dp->i_mount,
 299                                                      node);
 300                                 xfs_trans_brelse(context->tp, bp);
 301                                 return -EFSCORRUPTED;
 302                         }
 303
 304                         dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 305                         btree = dp->d_ops->node_tree_p(node);
 306                         for (i = 0; i < nodehdr.count; btree++, i++) {
 307                                 if (cursor->hashval
 308                                                 <= be32_to_cpu(btree->hashval)) {
 309                                         cursor->blkno = be32_to_cpu(btree->before);
 310                                         trace_xfs_attr_list_node_descend(context,
 311                                                                          btree);
 312                                         break;
 313                                 }
 314                         }
 315                         if (i == nodehdr.count) {
 316                                 xfs_trans_brelse(context->tp, bp);
 317                                 return 0;
 318                         }
 319                         xfs_trans_brelse(context->tp, bp);
 320                 }
 321         }
 322         ASSERT(bp != NULL);
 323
 324         /*
 325          * Roll upward through the blocks, processing each leaf block in
 326          * order.  As long as there is space in the result buffer, keep
 327          * adding the information.
 328          */
 329         for (;;) {
 330                 leaf = bp->b_addr;
 331                 xfs_attr3_leaf_list_int(bp, context);
 332                 xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &leafhdr, leaf);
 333                 if (context->seen_enough || leafhdr.forw == 0)
 334                         break;
 335                 cursor->blkno = leafhdr.forw;
 336                 xfs_trans_brelse(context->tp, bp);
 337                 error = xfs_attr3_leaf_read(context->tp, dp, cursor->blkno, -1, &bp);
 338                 if (error)
 339                         return error;
 340         }
 341         xfs_trans_brelse(context->tp, bp);
 342         return 0;
 343 }
 344
 345 /*
 346  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
 347  */
 348 void
 349 xfs_attr3_leaf_list_int(
 350         struct xfs_buf                  *bp,
 351         struct xfs_attr_list_context    *context)
 352 {
 353         struct attrlist_cursor_kern     *cursor;
 354         struct xfs_attr_leafblock       *leaf;
 355         struct xfs_attr3_icleaf_hdr     ichdr;
 356         struct xfs_attr_leaf_entry      *entries;
 357         struct xfs_attr_leaf_entry      *entry;
 358         int                             i;
 359         struct xfs_mount                *mp = context->dp->i_mount;
 360
 361         trace_xfs_attr_list_leaf(context);
 362
 363         leaf = bp->b_addr;
 364         xfs_attr3_leaf_hdr_from_disk(mp->m_attr_geo, &ichdr, leaf);
 365         entries = xfs_attr3_leaf_entryp(leaf);
 366
 367         cursor = context->cursor;
 368         cursor->initted = 1;
 369
 370         /*
 371          * Re-find our place in the leaf block if this is a new syscall.
 372          */
 373         if (context->resynch) {
 374                 entry = &entries[0];
 375                 for (i = 0; i < ichdr.count; entry++, i++) {
 376                         if (be32_to_cpu(entry->hashval) == cursor->hashval) {
 377                                 if (cursor->offset == context->dupcnt) {
 378                                         context->dupcnt = 0;
 379                                         break;
 380                                 }
 381                                 context->dupcnt++;
 382                         } else if (be32_to_cpu(entry->hashval) >
 383                                         cursor->hashval) {
 384                                 context->dupcnt = 0;
 385                                 break;
 386                         }
 387                 }
 388                 if (i == ichdr.count) {
 389                         trace_xfs_attr_list_notfound(context);
 390                         return;
 391                 }
 392         } else {
 393                 entry = &entries[0];
 394                 i = 0;
 395         }
 396         context->resynch = 0;
 397
 398         /*
 399          * We have found our place, start copying out the new attributes.
 400          */
 401         for (; i < ichdr.count; entry++, i++) {
 402                 char *name;
 403                 int namelen, valuelen;
 404
 405                 if (be32_to_cpu(entry->hashval) != cursor->hashval) {
 406                         cursor->hashval = be32_to_cpu(entry->hashval);
 407                         cursor->offset = 0;
 408                 }
 409
 410                 if (entry->flags & XFS_ATTR_INCOMPLETE)
 411                         continue;               /* skip incomplete entries */
 412
 413                 if (entry->flags & XFS_ATTR_LOCAL) {
 414                         xfs_attr_leaf_name_local_t *name_loc;
 415
 416                         name_loc = xfs_attr3_leaf_name_local(leaf, i);
 417                         name = name_loc->nameval;
 418                         namelen = name_loc->namelen;
 419                         valuelen = be16_to_cpu(name_loc->valuelen);
 420                 } else {
 421                         xfs_attr_leaf_name_remote_t *name_rmt;
 422
 423                         name_rmt = xfs_attr3_leaf_name_remote(leaf, i);
 424                         name = name_rmt->name;
 425                         namelen = name_rmt->namelen;
 426                         valuelen = be32_to_cpu(name_rmt->valuelen);
 427                 }
 428
 429                 context->put_listent(context, entry->flags,
 430                                               name, namelen, valuelen);
 431                 if (context->seen_enough)
 432                         break;
 433                 cursor->offset++;
 434         }
 435         trace_xfs_attr_list_leaf_end(context);
 436         return;
 437 }
 438
 439 /*
 440  * Copy out attribute entries for attr_list(), for leaf attribute lists.
 441  */
 442 STATIC int
 443 xfs_attr_leaf_list(xfs_attr_list_context_t *context)
 444 {
 445         int error;
 446         struct xfs_buf *bp;
 447
 448         trace_xfs_attr_leaf_list(context);
 449
 450         context->cursor->blkno = 0;
 451         error = xfs_attr3_leaf_read(context->tp, context->dp, 0, -1, &bp);
 452         if (error)
 453                 return error;
 454
 455         xfs_attr3_leaf_list_int(bp, context);
 456         xfs_trans_brelse(context->tp, bp);
 457         return 0;
 458 }
 459
 460 int
 461 xfs_attr_list_int_ilocked(
 462         struct xfs_attr_list_context    *context)
 463 {
 464         struct xfs_inode                *dp = context->dp;
 465
 466         ASSERT(xfs_isilocked(dp, XFS_ILOCK_SHARED | XFS_ILOCK_EXCL));
 467
 468         /*
 469          * Decide on what work routines to call based on the inode size.
 470          */
 471         if (!xfs_inode_hasattr(dp))
 472                 return 0;
 473         else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL)
 474                 return xfs_attr_shortform_list(context);
 475         else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
 476                 return xfs_attr_leaf_list(context);
 477         return xfs_attr_node_list(context);
 478 }
 479
 480 int
 481 xfs_attr_list_int(
 482         xfs_attr_list_context_t *context)
 483 {
 484         int error;
 485         xfs_inode_t *dp = context->dp;
 486         uint            lock_mode;
 487
 488         XFS_STATS_INC(dp->i_mount, xs_attr_list);
 489
 490         if (XFS_FORCED_SHUTDOWN(dp->i_mount))
 491                 return -EIO;
 492
 493         lock_mode = xfs_ilock_attr_map_shared(dp);
 494         error = xfs_attr_list_int_ilocked(context);
 495         xfs_iunlock(dp, lock_mode);
 496         return error;
 497 }
 498
 499 #define ATTR_ENTBASESIZE                /* minimum bytes used by an attr */ \
 500         (((struct attrlist_ent *) 0)->a_name - (char *) 0)
 501 #define ATTR_ENTSIZE(namelen)           /* actual bytes used by an attr */ \
 502         ((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
 503          & ~(sizeof(u_int32_t)-1))
 504
 505 /*
 506  * Format an attribute and copy it out to the user's buffer.
 507  * Take care to check values and protect against them changing later,
 508  * we may be reading them directly out of a user buffer.
 509  */
 510 STATIC void
 511 xfs_attr_put_listent(
 512         xfs_attr_list_context_t *context,
 513         int             flags,
 514         unsigned char   *name,
 515         int             namelen,
 516         int             valuelen)
 517 {
 518         struct attrlist *alist = (struct attrlist *)context->alist;
 519         attrlist_ent_t *aep;
 520         int arraytop;
 521
 522         ASSERT(!(context->flags & ATTR_KERNOVAL));
 523         ASSERT(context->count >= 0);
 524         ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
 525         ASSERT(context->firstu >= sizeof(*alist));
 526         ASSERT(context->firstu <= context->bufsize);
 527
 528         /*
 529          * Only list entries in the right namespace.
 530          */
 531         if (((context->flags & ATTR_SECURE) == 0) !=
 532             ((flags & XFS_ATTR_SECURE) == 0))
 533                 return;
 534         if (((context->flags & ATTR_ROOT) == 0) !=
 535             ((flags & XFS_ATTR_ROOT) == 0))
 536                 return;
 537
 538         arraytop = sizeof(*alist) +
 539                         context->count * sizeof(alist->al_offset[0]);
 540         context->firstu -= ATTR_ENTSIZE(namelen);
 541         if (context->firstu < arraytop) {
 542                 trace_xfs_attr_list_full(context);
 543                 alist->al_more = 1;
 544                 context->seen_enough = 1;
 545                 return;
 546         }
 547
 548         aep = (attrlist_ent_t *)&context->alist[context->firstu];
 549         aep->a_valuelen = valuelen;
 550         memcpy(aep->a_name, name, namelen);
 551         aep->a_name[namelen] = 0;
 552         alist->al_offset[context->count++] = context->firstu;
 553         alist->al_count = context->count;
 554         trace_xfs_attr_list_add(context);
 555         return;
 556 }
 557
 558 /*
 559  * Generate a list of extended attribute names and optionally
 560  * also value lengths.  Positive return value follows the XFS
 561  * convention of being an error, zero or negative return code
 562  * is the length of the buffer returned (negated), indicating
 563  * success.
 564  */
 565 int
 566 xfs_attr_list(
 567         xfs_inode_t     *dp,
 568         char            *buffer,
 569         int             bufsize,
 570         int             flags,
 571         attrlist_cursor_kern_t *cursor)
 572 {
 573         xfs_attr_list_context_t context;
 574         struct attrlist *alist;
 575         int error;
 576
 577         /*
 578          * Validate the cursor.
 579          */
 580         if (cursor->pad1 || cursor->pad2)
 581                 return -EINVAL;
 582         if ((cursor->initted == 0) &&
 583             (cursor->hashval || cursor->blkno || cursor->offset))
 584                 return -EINVAL;
 585
 586         /*
 587          * Check for a properly aligned buffer.
 588          */
 589         if (((long)buffer) & (sizeof(int)-1))
 590                 return -EFAULT;
 591         if (flags & ATTR_KERNOVAL)
 592                 bufsize = 0;
 593
 594         /*
 595          * Initialize the output buffer.
 596          */
 597         memset(&context, 0, sizeof(context));
 598         context.dp = dp;
 599         context.cursor = cursor;
 600         context.resynch = 1;
 601         context.flags = flags;
 602         context.alist = buffer;
 603         context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
 604         context.firstu = context.bufsize;
 605         context.put_listent = xfs_attr_put_listent;
 606
 607         alist = (struct attrlist *)context.alist;
 608         alist->al_count = 0;
 609         alist->al_more = 0;
 610         alist->al_offset[0] = context.bufsize;
 611
 612         error = xfs_attr_list_int(&context);
 613         ASSERT(error <= 0);
 614         return error;
 615 }