src/afs/afs_cell.c

   1 /*
   2  * Copyright 2000, International Business Machines Corporation and others.
   3  * All Rights Reserved.
   4  *
   5  * This software has been released under the terms of the IBM Public
   6  * License.  For details, see the LICENSE file in the top-level source
   7  * directory or online at http://www.openafs.org/dl/license10.html
   8  */
   9
  10 /*
  11  * Implements:
  12  */
  13 #include <afsconfig.h>
  14 #include "afs/param.h"
  15
  16 RCSID
  17     ("$Header: /cvs/openafs/src/afs/afs_cell.c,v 1.30.2.3 2005/09/23 14:56:26 shadow Exp $");
  18
  19 #include "afs/stds.h"
  20 #include "afs/sysincludes.h"    /* Standard vendor system headers */
  21 #include "afsincludes.h"        /* Afs-based standard headers */
  22 #include "afs/afs_stats.h"      /* afs statistics */
  23 #include "afs/afs_osi.h"
  24
  25 /* Local variables. */
  26 afs_rwlock_t afs_xcell;         /* Export for cmdebug peeking at locks */
  27
  28 /*
  29  * AFSDB implementation:
  30  *
  31  * afs_StopAFSDB: terminate the AFSDB handler, used on shutdown
  32  * afs_AFSDBHandler: entry point for user-space AFSDB request handler
  33  * afs_GetCellHostsAFSDB: query the AFSDB handler and wait for response
  34  * afs_LookupAFSDB: look up AFSDB for given cell name and create locally
  35  */
  36
  37 #ifdef AFS_AFSDB_ENV
  38 static afs_rwlock_t afsdb_client_lock;  /* Serializes client requests */
  39 static char afsdb_handler_running;      /* Protected by GLOCK */
  40 static char afsdb_handler_shutdown;     /* Protected by GLOCK */
  41
  42 static struct {
  43     afs_rwlock_t lock;
  44     char pending;
  45     char complete;
  46     char *cellname;
  47     afs_int32 *cellhosts;
  48     int *timeout;
  49     char **realname;
  50 } afsdb_req;
  51
  52 void
  53 afs_StopAFSDB()
  54 {
  55     if (afsdb_handler_running) {
  56         afs_osi_Wakeup(&afsdb_req);
  57     } else {
  58         afsdb_handler_shutdown = 1;
  59         afs_termState = AFSOP_STOP_RXEVENT;
  60     }
  61 }
  62
  63 int
  64 afs_AFSDBHandler(char *acellName, int acellNameLen, afs_int32 * kernelMsg)
  65 {
  66     if (afsdb_handler_shutdown)
  67         return -2;
  68     afsdb_handler_running = 1;
  69
  70     ObtainSharedLock(&afsdb_req.lock, 683);
  71     if (afsdb_req.pending) {
  72         int i, hostCount;
  73
  74         UpgradeSToWLock(&afsdb_req.lock, 684);
  75         hostCount = kernelMsg[0];
  76         *afsdb_req.timeout = kernelMsg[1];
  77         if (*afsdb_req.timeout)
  78             *afsdb_req.timeout += osi_Time();
  79         *afsdb_req.realname = afs_strdup(acellName);
  80
  81         for (i = 0; i < MAXCELLHOSTS; i++) {
  82             if (i >= hostCount)
  83                 afsdb_req.cellhosts[i] = 0;
  84             else
  85                 afsdb_req.cellhosts[i] = kernelMsg[2 + i];
  86         }
  87
  88         /* Request completed, wake up the relevant thread */
  89         afsdb_req.pending = 0;
  90         afsdb_req.complete = 1;
  91         afs_osi_Wakeup(&afsdb_req);
  92         ConvertWToSLock(&afsdb_req.lock);
  93     }
  94     ConvertSToRLock(&afsdb_req.lock);
  95
  96     /* Wait for a request */
  97     while (afsdb_req.pending == 0 && afs_termState != AFSOP_STOP_AFSDB) {
  98         ReleaseReadLock(&afsdb_req.lock);
  99         afs_osi_Sleep(&afsdb_req);
 100         ObtainReadLock(&afsdb_req.lock);
 101     }
 102
 103     /* Check if we're shutting down */
 104     if (afs_termState == AFSOP_STOP_AFSDB) {
 105         ReleaseReadLock(&afsdb_req.lock);
 106
 107         /* Inform anyone waiting for us that we're going away */
 108         afsdb_handler_shutdown = 1;
 109         afsdb_handler_running = 0;
 110         afs_osi_Wakeup(&afsdb_req);
 111
 112         afs_termState = AFSOP_STOP_RXEVENT;
 113         afs_osi_Wakeup(&afs_termState);
 114         return -2;
 115     }
 116
 117     /* Return the lookup request to userspace */
 118     strncpy(acellName, afsdb_req.cellname, acellNameLen);
 119     ReleaseReadLock(&afsdb_req.lock);
 120     return 0;
 121 }
 122
 123 static int
 124 afs_GetCellHostsAFSDB(char *acellName, afs_int32 * acellHosts, int *timeout,
 125                       char **realName)
 126 {
 127     AFS_ASSERT_GLOCK();
 128     if (!afsdb_handler_running)
 129         return ENOENT;
 130
 131     ObtainWriteLock(&afsdb_client_lock, 685);
 132     ObtainWriteLock(&afsdb_req.lock, 686);
 133
 134     *acellHosts = 0;
 135     afsdb_req.cellname = acellName;
 136     afsdb_req.cellhosts = acellHosts;
 137     afsdb_req.timeout = timeout;
 138     afsdb_req.realname = realName;
 139
 140     afsdb_req.complete = 0;
 141     afsdb_req.pending = 1;
 142     afs_osi_Wakeup(&afsdb_req);
 143     ConvertWToRLock(&afsdb_req.lock);
 144
 145     while (afsdb_handler_running && !afsdb_req.complete) {
 146         ReleaseReadLock(&afsdb_req.lock);
 147         afs_osi_Sleep(&afsdb_req);
 148         ObtainReadLock(&afsdb_req.lock);
 149     };
 150     ReleaseReadLock(&afsdb_req.lock);
 151     ReleaseWriteLock(&afsdb_client_lock);
 152
 153     if (*acellHosts)
 154         return 0;
 155     else
 156         return ENOENT;
 157 }
 158 #endif
 159
 160 void
 161 afs_LookupAFSDB(char *acellName)
 162 {
 163 #ifdef AFS_AFSDB_ENV
 164     afs_int32 cellHosts[MAXCELLHOSTS];
 165     char *realName = NULL;
 166     int code, timeout;
 167
 168     code = afs_GetCellHostsAFSDB(acellName, cellHosts, &timeout, &realName);
 169     if (code)
 170         goto done;
 171     code = afs_NewCell(realName, cellHosts, CNoSUID, NULL, 0, 0, timeout);
 172     if (code && code != EEXIST)
 173         goto done;
 174
 175     /* If we found an alias, create it */
 176     if (afs_strcasecmp(acellName, realName))
 177         afs_NewCellAlias(acellName, realName);
 178
 179   done:
 180     if (realName)
 181         afs_osi_FreeStr(realName);
 182 #endif
 183 }
 184
 185 /*
 186  * Cell name-to-ID mapping
 187  *
 188  * afs_cellname_new: create a new cell name, optional cell number
 189  * afs_cellname_lookup_id: look up a cell name
 190  * afs_cellname_lookup_name: look up a cell number
 191  * afs_cellname_ref: note that this cell name was referenced somewhere
 192  * afs_cellname_init: load the list of cells from given inode
 193  * afs_cellname_write: write in-kernel list of cells to disk
 194  */
 195
 196 struct cell_name *afs_cellname_head;    /* Export for kdump */
 197 static ino_t afs_cellname_inode;
 198 static int afs_cellname_inode_set;
 199 static int afs_cellname_dirty;
 200 static afs_int32 afs_cellnum_next;
 201
 202 static struct cell_name *
 203 afs_cellname_new(char *name, afs_int32 cellnum)
 204 {
 205     struct cell_name *cn;
 206
 207     if (cellnum == 0)
 208         cellnum = afs_cellnum_next;
 209
 210     cn = (struct cell_name *)afs_osi_Alloc(sizeof(*cn));
 211     cn->next = afs_cellname_head;
 212     cn->cellnum = cellnum;
 213     cn->cellname = afs_strdup(name);
 214     cn->used = 0;
 215     afs_cellname_head = cn;
 216
 217     if (cellnum >= afs_cellnum_next)
 218         afs_cellnum_next = cellnum + 1;
 219
 220     return cn;
 221 }
 222
 223 static struct cell_name *
 224 afs_cellname_lookup_id(afs_int32 cellnum)
 225 {
 226     struct cell_name *cn;
 227
 228     for (cn = afs_cellname_head; cn; cn = cn->next)
 229         if (cn->cellnum == cellnum)
 230             return cn;
 231
 232     return NULL;
 233 }
 234
 235 static struct cell_name *
 236 afs_cellname_lookup_name(char *name)
 237 {
 238     struct cell_name *cn;
 239
 240     for (cn = afs_cellname_head; cn; cn = cn->next)
 241         if (strcmp(cn->cellname, name) == 0)
 242             return cn;
 243
 244     return NULL;
 245 }
 246
 247 static void
 248 afs_cellname_ref(struct cell_name *cn)
 249 {
 250     if (!cn->used) {
 251         cn->used = 1;
 252         afs_cellname_dirty = 1;
 253     }
 254 }
 255
 256 int
 257 afs_cellname_init(ino_t inode, int lookupcode)
 258 {
 259     struct osi_file *tfile;
 260     int cc, off = 0;
 261
 262     ObtainWriteLock(&afs_xcell, 692);
 263
 264     afs_cellnum_next = 1;
 265     afs_cellname_dirty = 0;
 266
 267     if (cacheDiskType == AFS_FCACHE_TYPE_MEM) {
 268         ReleaseWriteLock(&afs_xcell);
 269         return 0;
 270     }
 271     if (lookupcode) {
 272         ReleaseWriteLock(&afs_xcell);
 273         return lookupcode;
 274     }
 275
 276     tfile = osi_UFSOpen(inode);
 277     if (!tfile) {
 278         ReleaseWriteLock(&afs_xcell);
 279         return EIO;
 280     }
 281
 282     afs_cellname_inode = inode;
 283     afs_cellname_inode_set = 1;
 284
 285     while (1) {
 286         afs_int32 cellnum, clen, magic;
 287         struct cell_name *cn;
 288         char *cellname;
 289
 290         cc = afs_osi_Read(tfile, off, &magic, sizeof(magic));
 291         if (cc != sizeof(magic))
 292             break;
 293         if (magic != AFS_CELLINFO_MAGIC)
 294             break;
 295         off += cc;
 296
 297         cc = afs_osi_Read(tfile, off, &cellnum, sizeof(cellnum));
 298         if (cc != sizeof(cellnum))
 299             break;
 300         off += cc;
 301
 302         cc = afs_osi_Read(tfile, off, &clen, sizeof(clen));
 303         if (cc != sizeof(clen))
 304             break;
 305         off += cc;
 306
 307         cellname = afs_osi_Alloc(clen + 1);
 308         if (!cellname)
 309             break;
 310
 311         cc = afs_osi_Read(tfile, off, cellname, clen);
 312         if (cc != clen) {
 313             afs_osi_Free(cellname, clen + 1);
 314             break;
 315         }
 316         off += cc;
 317         cellname[clen] = '\0';
 318
 319         if (afs_cellname_lookup_name(cellname)
 320             || afs_cellname_lookup_id(cellnum)) {
 321             afs_osi_Free(cellname, clen + 1);
 322             break;
 323         }
 324
 325         cn = afs_cellname_new(cellname, cellnum);
 326         afs_osi_Free(cellname, clen + 1);
 327     }
 328
 329     osi_UFSClose(tfile);
 330     ReleaseWriteLock(&afs_xcell);
 331     return 0;
 332 }
 333
 334 int
 335 afs_cellname_write(void)
 336 {
 337     struct osi_file *tfile;
 338     struct cell_name *cn;
 339     int off;
 340
 341     if (!afs_cellname_dirty || !afs_cellname_inode_set)
 342         return 0;
 343     if (afs_initState != 300)
 344         return 0;
 345
 346     ObtainWriteLock(&afs_xcell, 693);
 347     afs_cellname_dirty = 0;
 348     off = 0;
 349     tfile = osi_UFSOpen(afs_cellname_inode);
 350     if (!tfile) {
 351         ReleaseWriteLock(&afs_xcell);
 352         return EIO;
 353     }
 354
 355     for (cn = afs_cellname_head; cn; cn = cn->next) {
 356         afs_int32 magic, cellnum, clen;
 357         int cc;
 358
 359         if (!cn->used)
 360             continue;
 361
 362         magic = AFS_CELLINFO_MAGIC;
 363         cc = afs_osi_Write(tfile, off, &magic, sizeof(magic));
 364         if (cc != sizeof(magic))
 365             break;
 366         off += cc;
 367
 368         cellnum = cn->cellnum;
 369         cc = afs_osi_Write(tfile, off, &cellnum, sizeof(cellnum));
 370         if (cc != sizeof(cellnum))
 371             break;
 372         off += cc;
 373
 374         clen = strlen(cn->cellname);
 375         cc = afs_osi_Write(tfile, off, &clen, sizeof(clen));
 376         if (cc != sizeof(clen))
 377             break;
 378         off += cc;
 379
 380         cc = afs_osi_Write(tfile, off, cn->cellname, clen);
 381         if (cc != clen)
 382             break;
 383         off += clen;
 384     }
 385
 386     osi_UFSClose(tfile);
 387     ReleaseWriteLock(&afs_xcell);
 388     return 0;
 389 }
 390
 391 /*
 392  * Cell alias implementation
 393  *
 394  * afs_FindCellAlias: look up cell alias by alias name
 395  * afs_GetCellAlias: get cell alias by index (starting at 0)
 396  * afs_PutCellAlias: put back a cell alias returned by Find or Get
 397  * afs_NewCellAlias: create new cell alias entry
 398  */
 399
 400 struct cell_alias *afs_cellalias_head;  /* Export for kdump */
 401 static afs_int32 afs_cellalias_index;
 402 static int afs_CellOrAliasExists_nl(char *aname);       /* Forward declaration */
 403
 404 static struct cell_alias *
 405 afs_FindCellAlias(char *alias)
 406 {
 407     struct cell_alias *tc;
 408
 409     for (tc = afs_cellalias_head; tc != NULL; tc = tc->next)
 410         if (!strcmp(alias, tc->alias))
 411             break;
 412     return tc;
 413 }
 414
 415 struct cell_alias *
 416 afs_GetCellAlias(int index)
 417 {
 418     struct cell_alias *tc;
 419
 420     ObtainReadLock(&afs_xcell);
 421     for (tc = afs_cellalias_head; tc != NULL; tc = tc->next)
 422         if (tc->index == index)
 423             break;
 424     ReleaseReadLock(&afs_xcell);
 425
 426     return tc;
 427 }
 428
 429 void
 430 afs_PutCellAlias(struct cell_alias *a)
 431 {
 432     return;
 433 }
 434
 435 afs_int32
 436 afs_NewCellAlias(char *alias, char *cell)
 437 {
 438     struct cell_alias *tc;
 439
 440     ObtainSharedLock(&afs_xcell, 681);
 441     if (afs_CellOrAliasExists_nl(alias)) {
 442         ReleaseSharedLock(&afs_xcell);
 443         return EEXIST;
 444     }
 445
 446     UpgradeSToWLock(&afs_xcell, 682);
 447     tc = (struct cell_alias *)afs_osi_Alloc(sizeof(struct cell_alias));
 448     tc->alias = afs_strdup(alias);
 449     tc->cell = afs_strdup(cell);
 450     tc->next = afs_cellalias_head;
 451     tc->index = afs_cellalias_index++;
 452     afs_cellalias_head = tc;
 453     ReleaseWriteLock(&afs_xcell);
 454
 455     afs_DynrootInvalidate();
 456     return 0;
 457 }
 458
 459 /*
 460  * Actual cell list implementation
 461  *
 462  * afs_UpdateCellLRU: bump given cell up to the front of the LRU queue
 463  * afs_RefreshCell: look up cell information in AFSDB if timeout expired
 464  *
 465  * afs_TraverseCells: execute a callback for each existing cell
 466  * afs_TraverseCells_nl: same as above except without locking afs_xcell
 467  * afs_choose_cell_by_{name,num,index}: useful traversal callbacks
 468  *
 469  * afs_FindCellByName: return a cell with a given name, if it exists
 470  * afs_FindCellByName_nl: same as above, without locking afs_xcell
 471  * afs_GetCellByName: same as FindCellByName but tries AFSDB if not found
 472  * afs_GetCell: return a cell with a given cell number
 473  * afs_GetCellStale: same as GetCell, but does not try to refresh the data
 474  * afs_GetCellByIndex: return a cell with a given index number (starting at 0)
 475  *
 476  * afs_GetPrimaryCell: return the primary cell, if any
 477  * afs_IsPrimaryCell: returns true iff the given cell is the primary cell
 478  * afs_IsPrimaryCellNum: returns afs_IsPrimaryCell(afs_GetCell(cellnum))
 479  * afs_SetPrimaryCell: set the primary cell name to the given cell name
 480  *
 481  * afs_NewCell: create or update a cell entry
 482  */
 483
 484 struct afs_q CellLRU;           /* Export for kdump */
 485 static char *afs_thiscell;
 486 afs_int32 afs_cellindex;        /* Export for kdump */
 487
 488 static void
 489 afs_UpdateCellLRU(struct cell *c)
 490 {
 491     ObtainWriteLock(&afs_xcell, 100);
 492     QRemove(&c->lruq);
 493     QAdd(&CellLRU, &c->lruq);
 494     ReleaseWriteLock(&afs_xcell);
 495 }
 496
 497 static void
 498 afs_RefreshCell(struct cell *ac)
 499 {
 500     if (ac->states & CNoAFSDB)
 501         return;
 502     if (!ac->cellHosts[0] || (ac->timeout && ac->timeout <= osi_Time()))
 503         afs_LookupAFSDB(ac->cellName);
 504 }
 505
 506 static void *
 507 afs_TraverseCells_nl(void *(*cb) (struct cell *, void *), void *arg)
 508 {
 509     struct afs_q *cq, *tq;
 510     struct cell *tc;
 511     void *ret = NULL;
 512
 513     for (cq = CellLRU.next; cq != &CellLRU; cq = tq) {
 514         tc = QTOC(cq);
 515
 516         /* This is assuming that a NULL return is acceptable. */
 517         if (cq) {
 518             tq = QNext(cq);
 519         } else {
 520             return NULL;
 521         }
 522
 523         ret = cb(tc, arg);
 524         if (ret)
 525             break;
 526     }
 527
 528     return ret;
 529 }
 530
 531 void *
 532 afs_TraverseCells(void *(*cb) (struct cell *, void *), void *arg)
 533 {
 534     void *ret;
 535
 536     ObtainReadLock(&afs_xcell);
 537     ret = afs_TraverseCells_nl(cb, arg);
 538     ReleaseReadLock(&afs_xcell);
 539
 540     return ret;
 541 }
 542
 543 static void *
 544 afs_choose_cell_by_name(struct cell *cell, void *arg)
 545 {
 546     if (!arg) {
 547         /* Safety net */
 548         return cell;
 549     } else {
 550         return strcmp(cell->cellName, (char *)arg) ? NULL : cell;
 551     }
 552 }
 553
 554 static void *
 555 afs_choose_cell_by_num(struct cell *cell, void *arg)
 556 {
 557     return (cell->cellNum == *((afs_int32 *) arg)) ? cell : NULL;
 558 }
 559
 560 static void *
 561 afs_choose_cell_by_index(struct cell *cell, void *arg)
 562 {
 563     return (cell->cellIndex == *((afs_int32 *) arg)) ? cell : NULL;
 564 }
 565
 566 static struct cell *
 567 afs_FindCellByName_nl(char *acellName, afs_int32 locktype)
 568 {
 569     return afs_TraverseCells_nl(&afs_choose_cell_by_name, acellName);
 570 }
 571
 572 static struct cell *
 573 afs_FindCellByName(char *acellName, afs_int32 locktype)
 574 {
 575     return afs_TraverseCells(&afs_choose_cell_by_name, acellName);
 576 }
 577
 578 struct cell *
 579 afs_GetCellByName(char *acellName, afs_int32 locktype)
 580 {
 581     struct cell *tc;
 582
 583     tc = afs_FindCellByName(acellName, locktype);
 584     if (!tc) {
 585         afs_LookupAFSDB(acellName);
 586         tc = afs_FindCellByName(acellName, locktype);
 587     }
 588     if (tc) {
 589         afs_cellname_ref(tc->cnamep);
 590         afs_UpdateCellLRU(tc);
 591         afs_RefreshCell(tc);
 592     }
 593
 594     return tc;
 595 }
 596
 597 struct cell *
 598 afs_GetCell(afs_int32 cellnum, afs_int32 locktype)
 599 {
 600     struct cell *tc;
 601     struct cell_name *cn;
 602
 603     tc = afs_GetCellStale(cellnum, locktype);
 604     if (tc) {
 605         afs_RefreshCell(tc);
 606     } else {
 607         ObtainReadLock(&afs_xcell);
 608         cn = afs_cellname_lookup_id(cellnum);
 609         ReleaseReadLock(&afs_xcell);
 610         if (cn)
 611             tc = afs_GetCellByName(cn->cellname, locktype);
 612     }
 613     return tc;
 614 }
 615
 616 struct cell *
 617 afs_GetCellStale(afs_int32 cellnum, afs_int32 locktype)
 618 {
 619     struct cell *tc;
 620
 621     tc = afs_TraverseCells(&afs_choose_cell_by_num, &cellnum);
 622     if (tc) {
 623         afs_cellname_ref(tc->cnamep);
 624         afs_UpdateCellLRU(tc);
 625     }
 626     return tc;
 627 }
 628
 629 struct cell *
 630 afs_GetCellByIndex(afs_int32 index, afs_int32 locktype)
 631 {
 632     struct cell *tc;
 633
 634     tc = afs_TraverseCells(&afs_choose_cell_by_index, &index);
 635     if (tc)
 636         afs_UpdateCellLRU(tc);
 637     return tc;
 638 }
 639
 640 struct cell *
 641 afs_GetPrimaryCell(afs_int32 locktype)
 642 {
 643     return afs_GetCellByName(afs_thiscell, locktype);
 644 }
 645
 646 int
 647 afs_IsPrimaryCell(struct cell *cell)
 648 {
 649     /* Simple safe checking */
 650     if (!cell) {
 651         return 0;
 652     } else if (!afs_thiscell) {
 653         /* This is simply a safety net to avoid seg faults especially when
 654          * using a user-space library.  afs_SetPrimaryCell() should be set
 655          * prior to this call. */
 656         afs_SetPrimaryCell(cell->cellName);
 657         return 1;
 658     } else {
 659         return strcmp(cell->cellName, afs_thiscell) ? 0 : 1;
 660     }
 661 }
 662
 663 int
 664 afs_IsPrimaryCellNum(afs_int32 cellnum)
 665 {
 666     struct cell *tc;
 667     int primary = 0;
 668
 669     tc = afs_GetCellStale(cellnum, READ_LOCK);
 670     if (tc) {
 671         primary = afs_IsPrimaryCell(tc);
 672         afs_PutCell(tc, READ_LOCK);
 673     }
 674
 675     return primary;
 676 }
 677
 678 afs_int32
 679 afs_SetPrimaryCell(char *acellName)
 680 {
 681     ObtainWriteLock(&afs_xcell, 691);
 682     if (afs_thiscell)
 683         afs_osi_FreeStr(afs_thiscell);
 684     afs_thiscell = afs_strdup(acellName);
 685     ReleaseWriteLock(&afs_xcell);
 686     return 0;
 687 }
 688
 689 afs_int32
 690 afs_NewCell(char *acellName, afs_int32 * acellHosts, int aflags,
 691             char *linkedcname, u_short fsport, u_short vlport, int timeout)
 692 {
 693     struct cell *tc, *tcl = 0;
 694     afs_int32 i, newc = 0, code = 0;
 695
 696     AFS_STATCNT(afs_NewCell);
 697
 698     ObtainWriteLock(&afs_xcell, 103);
 699
 700     tc = afs_FindCellByName_nl(acellName, READ_LOCK);
 701     if (tc) {
 702         aflags &= ~CNoSUID;
 703     } else {
 704         tc = (struct cell *)afs_osi_Alloc(sizeof(struct cell));
 705         memset((char *)tc, 0, sizeof(*tc));
 706         tc->cellName = afs_strdup(acellName);
 707         tc->fsport = AFS_FSPORT;
 708         tc->vlport = AFS_VLPORT;
 709         RWLOCK_INIT(&tc->lock, "cell lock");
 710         newc = 1;
 711         aflags |= CNoSUID;
 712     }
 713     ObtainWriteLock(&tc->lock, 688);
 714
 715     /* If the cell we've found has the correct name but no timeout,
 716      * and we're called with a non-zero timeout, bail out:  never
 717      * override static configuration entries with AFSDB ones.
 718      * One exception: if the original cell entry had no servers,
 719      * it must get servers from AFSDB.
 720      */
 721     if (timeout && !tc->timeout && tc->cellHosts[0]) {
 722         code = EEXIST;          /* This code is checked for in afs_LookupAFSDB */
 723         goto bad;
 724     }
 725
 726     /* we don't want to keep pinging old vlservers which were down,
 727      * since they don't matter any more.  It's easier to do this than
 728      * to remove the server from its various hash tables. */
 729     for (i = 0; i < MAXCELLHOSTS; i++) {
 730         if (!tc->cellHosts[i])
 731             break;
 732         tc->cellHosts[i]->flags &= ~SRVR_ISDOWN;
 733         tc->cellHosts[i]->flags |= SRVR_ISGONE;
 734     }
 735
 736     if (fsport)
 737         tc->fsport = fsport;
 738     if (vlport)
 739         tc->vlport = vlport;
 740
 741     if (aflags & CLinkedCell) {
 742         if (!linkedcname) {
 743             code = EINVAL;
 744             goto bad;
 745         }
 746         tcl = afs_FindCellByName_nl(linkedcname, READ_LOCK);
 747         if (!tcl) {
 748             code = ENOENT;
 749             goto bad;
 750         }
 751         if (tcl->lcellp) {      /* XXX Overwriting if one existed before! XXX */
 752             tcl->lcellp->lcellp = (struct cell *)0;
 753             tcl->lcellp->states &= ~CLinkedCell;
 754         }
 755         tc->lcellp = tcl;
 756         tcl->lcellp = tc;
 757     }
 758     tc->states |= aflags;
 759     tc->timeout = timeout;
 760
 761     memset((char *)tc->cellHosts, 0, sizeof(tc->cellHosts));
 762     for (i = 0; i < MAXCELLHOSTS; i++) {
 763         struct server *ts;
 764         afs_uint32 temp = acellHosts[i];
 765         if (!temp)
 766             break;
 767         ts = afs_GetServer(&temp, 1, 0, tc->vlport, WRITE_LOCK, NULL, 0);
 768         ts->cell = tc;
 769         ts->flags &= ~SRVR_ISGONE;
 770         tc->cellHosts[i] = ts;
 771         afs_PutServer(ts, WRITE_LOCK);
 772     }
 773     afs_SortServers(tc->cellHosts, MAXCELLHOSTS);       /* randomize servers */
 774
 775     if (newc) {
 776         struct cell_name *cn;
 777
 778         cn = afs_cellname_lookup_name(acellName);
 779         if (!cn)
 780             cn = afs_cellname_new(acellName, 0);
 781
 782         tc->cnamep = cn;
 783         tc->cellNum = cn->cellnum;
 784         tc->cellIndex = afs_cellindex++;
 785         afs_stats_cmperf.numCellsVisible++;
 786         QAdd(&CellLRU, &tc->lruq);
 787     }
 788
 789     ReleaseWriteLock(&tc->lock);
 790     ReleaseWriteLock(&afs_xcell);
 791     afs_PutCell(tc, 0);
 792     afs_DynrootInvalidate();
 793     return 0;
 794
 795   bad:
 796     if (newc) {
 797         afs_osi_FreeStr(tc->cellName);
 798         afs_osi_Free(tc, sizeof(struct cell));
 799     }
 800     ReleaseWriteLock(&tc->lock);
 801     ReleaseWriteLock(&afs_xcell);
 802     return code;
 803 }
 804
 805 /*
 806  * Miscellaneous stuff
 807  *
 808  * afs_CellInit: perform whatever initialization is necessary
 809  * shutdown_cell: called on shutdown, should deallocate memory, etc
 810  * afs_RemoveCellEntry: remove a server from a cell's server list
 811  * afs_CellOrAliasExists: check if the given name exists as a cell or alias
 812  * afs_CellOrAliasExists_nl: same as above without locking afs_xcell
 813  * afs_CellNumValid: check if a cell number is valid (also set the used flag)
 814  */
 815
 816 void
 817 afs_CellInit()
 818 {
 819     RWLOCK_INIT(&afs_xcell, "afs_xcell");
 820 #ifdef AFS_AFSDB_ENV
 821     RWLOCK_INIT(&afsdb_client_lock, "afsdb_client_lock");
 822     RWLOCK_INIT(&afsdb_req.lock, "afsdb_req.lock");
 823 #endif
 824     QInit(&CellLRU);
 825
 826     afs_cellindex = 0;
 827     afs_cellalias_index = 0;
 828 }
 829
 830 void
 831 shutdown_cell()
 832 {
 833     struct afs_q *cq, *tq;
 834     struct cell *tc;
 835
 836     RWLOCK_INIT(&afs_xcell, "afs_xcell");
 837
 838     for (cq = CellLRU.next; cq != &CellLRU; cq = tq) {
 839         tc = QTOC(cq);
 840         tq = QNext(cq);
 841         if (tc->cellName)
 842             afs_osi_FreeStr(tc->cellName);
 843         afs_osi_Free(tc, sizeof(struct cell));
 844     }
 845     QInit(&CellLRU);
 846
 847 {
 848     struct cell_name *cn = afs_cellname_head;
 849
 850     while (cn) {
 851         struct cell_name *next = cn->next;
 852
 853         afs_osi_FreeStr(cn->cellname);
 854         afs_osi_Free(cn, sizeof(struct cell_name));
 855         cn = next;
 856     }
 857 }
 858 }
 859
 860 void
 861 afs_RemoveCellEntry(struct server *srvp)
 862 {
 863     struct cell *tc;
 864     afs_int32 j, k;
 865
 866     tc = srvp->cell;
 867     if (!tc)
 868         return;
 869
 870     /* Remove the server structure from the cell list - if there */
 871     ObtainWriteLock(&tc->lock, 200);
 872     for (j = k = 0; j < MAXCELLHOSTS; j++) {
 873         if (!tc->cellHosts[j])
 874             break;
 875         if (tc->cellHosts[j] != srvp) {
 876             tc->cellHosts[k++] = tc->cellHosts[j];
 877         }
 878     }
 879     if (k == 0) {
 880         /* What do we do if we remove the last one? */
 881     }
 882     for (; k < MAXCELLHOSTS; k++) {
 883         tc->cellHosts[k] = 0;
 884     }
 885     ReleaseWriteLock(&tc->lock);
 886 }
 887
 888 static int
 889 afs_CellOrAliasExists_nl(char *aname)
 890 {
 891     struct cell *c;
 892     struct cell_alias *ca;
 893
 894     c = afs_FindCellByName_nl(aname, READ_LOCK);
 895     if (c) {
 896         afs_PutCell(c, READ_LOCK);
 897         return 1;
 898     }
 899
 900     ca = afs_FindCellAlias(aname);
 901     if (ca) {
 902         afs_PutCellAlias(ca);
 903         return 1;
 904     }
 905
 906     return 0;
 907 }
 908
 909 int
 910 afs_CellOrAliasExists(char *aname)
 911 {
 912     int ret;
 913
 914     ObtainReadLock(&afs_xcell);
 915     ret = afs_CellOrAliasExists_nl(aname);
 916     ReleaseReadLock(&afs_xcell);
 917
 918     return ret;
 919 }
 920
 921 int
 922 afs_CellNumValid(afs_int32 cellnum)
 923 {
 924     struct cell_name *cn;
 925
 926     ObtainReadLock(&afs_xcell);
 927     cn = afs_cellname_lookup_id(cellnum);
 928     ReleaseReadLock(&afs_xcell);
 929     if (cn) {
 930         cn->used = 1;
 931         return 1;
 932     } else {
 933         return 0;
 934     }
 935 }