source3/smbd/blocking.c

   1 /*
   2    Unix SMB/Netbios implementation.
   3    Version 1.9.
   4    Blocking Locking functions
   5    Copyright (C) Jeremy Allison 1998
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20 */
  21
  22 #include "includes.h"
  23
  24 extern char *OutBuffer;
  25
  26 /****************************************************************************
  27  This is the structure to queue to implement blocking locks.
  28  notify. It consists of the requesting SMB and the expiry time.
  29 *****************************************************************************/
  30
  31 typedef struct {
  32   ubi_slNode msg_next;
  33   int com_type;
  34   files_struct *fsp;
  35   time_t expire_time;
  36   int lock_num;
  37   char *inbuf;
  38   int length;
  39 } blocking_lock_record;
  40
  41 static ubi_slList blocking_lock_queue = { NULL, (ubi_slNodePtr)&blocking_lock_queue, 0};
  42
  43 /****************************************************************************
  44  Destructor for the above structure.
  45 ****************************************************************************/
  46
  47 static void free_blocking_lock_record(blocking_lock_record *blr)
  48 {
  49   SAFE_FREE(blr->inbuf);
  50   SAFE_FREE(blr);
  51 }
  52
  53 /****************************************************************************
  54  Get the files_struct given a particular queued SMB.
  55 *****************************************************************************/
  56
  57 static files_struct *get_fsp_from_pkt(char *inbuf)
  58 {
  59   switch(CVAL(inbuf,smb_com)) {
  60   case SMBlock:
  61   case SMBlockread:
  62     return file_fsp(inbuf,smb_vwv0);
  63   case SMBlockingX:
  64     return file_fsp(inbuf,smb_vwv2);
  65   default:
  66     DEBUG(0,("get_fsp_from_pkt: PANIC - unknown type on blocking lock queue - exiting.!\n"));
  67     exit_server("PANIC - unknown type on blocking lock queue");
  68   }
  69   return NULL; /* Keep compiler happy. */
  70 }
  71
  72 /****************************************************************************
  73  Determine if this is a secondary element of a chained SMB.
  74   **************************************************************************/
  75
  76 static BOOL in_chained_smb(void)
  77 {
  78   return (chain_size != 0);
  79 }
  80
  81 /****************************************************************************
  82  Function to push a blocking lock request onto the lock queue.
  83 ****************************************************************************/
  84
  85 BOOL push_blocking_lock_request( char *inbuf, int length, int lock_timeout, int lock_num)
  86 {
  87   blocking_lock_record *blr;
  88
  89   if(in_chained_smb() ) {
  90     DEBUG(0,("push_blocking_lock_request: cannot queue a chained request (currently).\n"));
  91     return False;
  92   }
  93
  94   /*
  95    * Now queue an entry on the blocking lock queue. We setup
  96    * the expiration time here.
  97    */
  98
  99   if((blr = (blocking_lock_record *)malloc(sizeof(blocking_lock_record))) == NULL) {
 100     DEBUG(0,("push_blocking_lock_request: Malloc fail !\n" ));
 101     return False;
 102   }
 103
 104   if((blr->inbuf = (char *)malloc(length)) == NULL) {
 105     DEBUG(0,("push_blocking_lock_request: Malloc fail (2)!\n" ));
 106     SAFE_FREE(blr);
 107     return False;
 108   }
 109
 110   blr->com_type = CVAL(inbuf,smb_com);
 111   blr->fsp = get_fsp_from_pkt(inbuf);
 112   blr->expire_time = (lock_timeout == -1) ? (time_t)-1 : time(NULL) + (time_t)lock_timeout;
 113   blr->lock_num = lock_num;
 114   memcpy(blr->inbuf, inbuf, length);
 115   blr->length = length;
 116
 117   ubi_slAddTail(&blocking_lock_queue, blr);
 118
 119
 120   DEBUG(3,("push_blocking_lock_request: lock request length=%d blocked with expiry time %d (+%d) \
 121 for fnum = %d, name = %s\n", length, (int)blr->expire_time, lock_timeout,
 122         blr->fsp->fnum, blr->fsp->fsp_name ));
 123
 124   return True;
 125 }
 126
 127 /****************************************************************************
 128  Return a smd with a given size.
 129 *****************************************************************************/
 130
 131 static void send_blocking_reply(char *outbuf, int outsize)
 132 {
 133         if(outsize > 4)
 134                 smb_setlen(outbuf,outsize - 4);
 135
 136         if (!send_smb(smbd_server_fd(),outbuf))
 137                 exit_server("send_blocking_reply: send_smb failed.\n");
 138 }
 139
 140 /****************************************************************************
 141  Return a lockingX success SMB.
 142 *****************************************************************************/
 143
 144 static void reply_lockingX_success(blocking_lock_record *blr)
 145 {
 146   char *outbuf = OutBuffer;
 147   int bufsize = BUFFER_SIZE;
 148   char *inbuf = blr->inbuf;
 149   int outsize = 0;
 150
 151   construct_reply_common(inbuf, outbuf);
 152   set_message(outbuf,2,0,True);
 153
 154   /*
 155    * As this message is a lockingX call we must handle
 156    * any following chained message correctly.
 157    * This is normally handled in construct_reply(),
 158    * but as that calls switch_message, we can't use
 159    * that here and must set up the chain info manually.
 160    */
 161
 162   outsize = chain_reply(inbuf,outbuf,blr->length,bufsize);
 163
 164   outsize += chain_size;
 165
 166   send_blocking_reply(outbuf,outsize);
 167 }
 168
 169 /****************************************************************************
 170  Return a generic lock fail error blocking call.
 171 *****************************************************************************/
 172
 173 static void generic_blocking_lock_error(blocking_lock_record *blr, NTSTATUS status)
 174 {
 175         char *outbuf = OutBuffer;
 176         char *inbuf = blr->inbuf;
 177         construct_reply_common(inbuf, outbuf);
 178
 179         ERROR_NT(status);
 180         if (!send_smb(smbd_server_fd(),outbuf))
 181                 exit_server("generic_blocking_lock_error: send_smb failed.\n");
 182 }
 183
 184 /****************************************************************************
 185  Return a lock fail error for a lockingX call. Undo all the locks we have
 186  obtained first.
 187 *****************************************************************************/
 188
 189 static void reply_lockingX_error(blocking_lock_record *blr, NTSTATUS status)
 190 {
 191         char *inbuf = blr->inbuf;
 192         files_struct *fsp = blr->fsp;
 193         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 194         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 195         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT) 0;
 196         uint16 lock_pid;
 197         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 198         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 199         char *data;
 200         int i;
 201
 202         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 203
 204         /*
 205          * Data now points at the beginning of the list
 206          * of smb_lkrng structs.
 207          */
 208
 209         /*
 210          * Ensure we don't do a remove on the lock that just failed,
 211          * as under POSIX rules, if we have a lock already there, we
 212          * will delete it (and we shouldn't) .....
 213          */
 214
 215         for(i = blr->lock_num - 1; i >= 0; i--) {
 216                 BOOL err;
 217
 218                 lock_pid = get_lock_pid( data, i, large_file_format);
 219                 count = get_lock_count( data, i, large_file_format);
 220                 offset = get_lock_offset( data, i, large_file_format, &err);
 221
 222                 /*
 223                  * We know err cannot be set as if it was the lock
 224                  * request would never have been queued. JRA.
 225                  */
 226
 227                 do_unlock(fsp,conn,lock_pid,count,offset);
 228         }
 229
 230         generic_blocking_lock_error(blr, status);
 231 }
 232
 233 /****************************************************************************
 234  Return a lock fail error.
 235 *****************************************************************************/
 236
 237 static void blocking_lock_reply_error(blocking_lock_record *blr, NTSTATUS status)
 238 {
 239         switch(blr->com_type) {
 240         case SMBlock:
 241         case SMBlockread:
 242                 generic_blocking_lock_error(blr, status);
 243                 break;
 244         case SMBlockingX:
 245                 reply_lockingX_error(blr, status);
 246                 break;
 247         default:
 248                 DEBUG(0,("blocking_lock_reply_error: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 249                 exit_server("PANIC - unknown type on blocking lock queue");
 250         }
 251 }
 252
 253 /****************************************************************************
 254  Attempt to finish off getting all pending blocking locks for a lockread call.
 255  Returns True if we want to be removed from the list.
 256 *****************************************************************************/
 257
 258 static BOOL process_lockread(blocking_lock_record *blr)
 259 {
 260         char *outbuf = OutBuffer;
 261         char *inbuf = blr->inbuf;
 262         ssize_t nread = -1;
 263         char *data, *p;
 264         int outsize = 0;
 265         SMB_OFF_T startpos;
 266         size_t numtoread;
 267         NTSTATUS status;
 268         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 269         files_struct *fsp = blr->fsp;
 270
 271         numtoread = SVAL(inbuf,smb_vwv1);
 272         startpos = IVAL(inbuf,smb_vwv2);
 273
 274         numtoread = MIN(BUFFER_SIZE-outsize,numtoread);
 275         data = smb_buf(outbuf) + 3;
 276
 277         status = do_lock( fsp, conn, SVAL(inbuf,smb_pid), (SMB_BIG_UINT)numtoread,
 278                           (SMB_BIG_UINT)startpos, READ_LOCK);
 279         if (NT_STATUS_V(status)) {
 280                 if ((errno != EACCES) && (errno != EAGAIN)) {
 281                         /*
 282                          * We have other than a "can't get lock" POSIX
 283                          * error. Send an error.
 284                          * Return True so we get dequeued.
 285                          */
 286                         generic_blocking_lock_error(blr, status);
 287                         return True;
 288                 }
 289
 290                 /*
 291                  * Still waiting for lock....
 292                  */
 293
 294                 DEBUG(10,("process_lockread: failed to get lock for file = %s. Still waiting....\n",
 295                           fsp->fsp_name));
 296                 return False;
 297         }
 298
 299         nread = read_file(fsp,data,startpos,numtoread);
 300
 301         if (nread < 0) {
 302                 generic_blocking_lock_error(blr,NT_STATUS_ACCESS_DENIED);
 303                 return True;
 304         }
 305
 306         construct_reply_common(inbuf, outbuf);
 307         outsize = set_message(outbuf,5,0,True);
 308
 309         outsize += nread;
 310         SSVAL(outbuf,smb_vwv0,nread);
 311         SSVAL(outbuf,smb_vwv5,nread+3);
 312         p = smb_buf(outbuf);
 313         *p++ = 1;
 314         SSVAL(p,0,nread); p += 2;
 315         set_message_end(outbuf, p+nread);
 316
 317         DEBUG(3, ( "process_lockread file = %s, fnum=%d num=%d nread=%d\n",
 318                    fsp->fsp_name, fsp->fnum, (int)numtoread, (int)nread ) );
 319
 320         send_blocking_reply(outbuf,outsize);
 321         return True;
 322 }
 323
 324 /****************************************************************************
 325  Attempt to finish off getting all pending blocking locks for a lock call.
 326  Returns True if we want to be removed from the list.
 327 *****************************************************************************/
 328
 329 static BOOL process_lock(blocking_lock_record *blr)
 330 {
 331         char *outbuf = OutBuffer;
 332         char *inbuf = blr->inbuf;
 333         int outsize;
 334         SMB_OFF_T count = 0, offset = 0;
 335         NTSTATUS status;
 336         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 337         files_struct *fsp = blr->fsp;
 338
 339         count = IVAL(inbuf,smb_vwv1);
 340         offset = IVAL(inbuf,smb_vwv3);
 341
 342         errno = 0;
 343         status = do_lock(fsp, conn, SVAL(inbuf,smb_pid), (SMB_BIG_UINT)count,
 344                          (SMB_BIG_UINT)offset, WRITE_LOCK);
 345         if (NT_STATUS_IS_ERR(status)) {
 346                 if((errno != EACCES) && (errno != EAGAIN)) {
 347                         /*
 348                          * We have other than a "can't get lock" POSIX
 349                          * error. Send an error.
 350                          * Return True so we get dequeued.
 351                          */
 352
 353                         blocking_lock_reply_error(blr, status);
 354                         return True;
 355                 }
 356                 /*
 357                  * Still can't get the lock - keep waiting.
 358                  */
 359                 DEBUG(10,("process_lock: failed to get lock for file = %s. Still waiting....\n",
 360                           fsp->fsp_name));
 361                 return False;
 362         }
 363
 364         /*
 365          * Success - we got the lock.
 366          */
 367
 368         DEBUG(3,("process_lock : file=%s fnum=%d offset=%.0f count=%.0f\n",
 369                  fsp->fsp_name, fsp->fnum, (double)offset, (double)count));
 370
 371         construct_reply_common(inbuf, outbuf);
 372         outsize = set_message(outbuf,0,0,True);
 373         send_blocking_reply(outbuf,outsize);
 374         return True;
 375 }
 376
 377 /****************************************************************************
 378  Attempt to finish off getting all pending blocking locks for a lockingX call.
 379  Returns True if we want to be removed from the list.
 380 *****************************************************************************/
 381
 382 static BOOL process_lockingX(blocking_lock_record *blr)
 383 {
 384         char *inbuf = blr->inbuf;
 385         unsigned char locktype = CVAL(inbuf,smb_vwv3);
 386         files_struct *fsp = blr->fsp;
 387         connection_struct *conn = conn_find(SVAL(inbuf,smb_tid));
 388         uint16 num_ulocks = SVAL(inbuf,smb_vwv6);
 389         uint16 num_locks = SVAL(inbuf,smb_vwv7);
 390         SMB_BIG_UINT count = (SMB_BIG_UINT)0, offset = (SMB_BIG_UINT)0;
 391         uint16 lock_pid;
 392         BOOL large_file_format = (locktype & LOCKING_ANDX_LARGE_FILES);
 393         char *data;
 394         NTSTATUS status = NT_STATUS_OK;
 395
 396         data = smb_buf(inbuf) + ((large_file_format ? 20 : 10)*num_ulocks);
 397
 398         /*
 399          * Data now points at the beginning of the list
 400          * of smb_lkrng structs.
 401          */
 402
 403         for(; blr->lock_num < num_locks; blr->lock_num++) {
 404                 BOOL err;
 405
 406                 lock_pid = get_lock_pid( data, blr->lock_num, large_file_format);
 407                 count = get_lock_count( data, blr->lock_num, large_file_format);
 408                 offset = get_lock_offset( data, blr->lock_num, large_file_format, &err);
 409
 410                 /*
 411                  * We know err cannot be set as if it was the lock
 412                  * request would never have been queued. JRA.
 413                  */
 414                 errno = 0;
 415                 status = do_lock(fsp,conn,lock_pid,count,offset,
 416                                  ((locktype & 1) ? READ_LOCK : WRITE_LOCK));
 417                 if (NT_STATUS_IS_ERR(status)) break;
 418         }
 419
 420         if(blr->lock_num == num_locks) {
 421                 /*
 422                  * Success - we got all the locks.
 423                  */
 424
 425                 DEBUG(3,("process_lockingX file = %s, fnum=%d type=%d num_locks=%d\n",
 426                          fsp->fsp_name, fsp->fnum, (unsigned int)locktype, num_locks) );
 427
 428                 reply_lockingX_success(blr);
 429                 return True;
 430         } else if ((errno != EACCES) && (errno != EAGAIN)) {
 431                 /*
 432                  * We have other than a "can't get lock" POSIX
 433                  * error. Free any locks we had and return an error.
 434                  * Return True so we get dequeued.
 435                  */
 436
 437                 blocking_lock_reply_error(blr, status);
 438                 return True;
 439         }
 440
 441         /*
 442          * Still can't get all the locks - keep waiting.
 443          */
 444
 445         DEBUG(10,("process_lockingX: only got %d locks of %d needed for file %s, fnum = %d. \
 446 Waiting....\n",
 447                   blr->lock_num, num_locks, fsp->fsp_name, fsp->fnum));
 448
 449         return False;
 450 }
 451
 452 /****************************************************************************
 453  Process a blocking lock SMB.
 454  Returns True if we want to be removed from the list.
 455 *****************************************************************************/
 456
 457 static BOOL blocking_lock_record_process(blocking_lock_record *blr)
 458 {
 459   switch(blr->com_type) {
 460   case SMBlock:
 461     return process_lock(blr);
 462   case SMBlockread:
 463     return process_lockread(blr);
 464   case SMBlockingX:
 465     return process_lockingX(blr);
 466   default:
 467     DEBUG(0,("blocking_lock_record_process: PANIC - unknown type on blocking lock queue - exiting.!\n"));
 468     exit_server("PANIC - unknown type on blocking lock queue");
 469   }
 470   return False; /* Keep compiler happy. */
 471 }
 472
 473 /****************************************************************************
 474  Delete entries by fnum from the blocking lock pending queue.
 475 *****************************************************************************/
 476
 477 void remove_pending_lock_requests_by_fid(files_struct *fsp)
 478 {
 479   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 480   blocking_lock_record *prev = NULL;
 481
 482   while(blr != NULL) {
 483     if(blr->fsp->fnum == fsp->fnum) {
 484
 485       DEBUG(10,("remove_pending_lock_requests_by_fid - removing request type %d for \
 486 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 487
 488       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 489       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 490       continue;
 491     }
 492
 493     prev = blr;
 494     blr = (blocking_lock_record *)ubi_slNext(blr);
 495   }
 496 }
 497
 498 /****************************************************************************
 499  Delete entries by mid from the blocking lock pending queue. Always send reply.
 500 *****************************************************************************/
 501
 502 void remove_pending_lock_requests_by_mid(int mid)
 503 {
 504   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 505   blocking_lock_record *prev = NULL;
 506
 507   while(blr != NULL) {
 508     if(SVAL(blr->inbuf,smb_mid) == mid) {
 509       files_struct *fsp = blr->fsp;
 510
 511       DEBUG(10,("remove_pending_lock_requests_by_mid - removing request type %d for \
 512 file %s fnum = %d\n", blr->com_type, fsp->fsp_name, fsp->fnum ));
 513
 514       blocking_lock_reply_error(blr,NT_STATUS_CANCELLED);
 515       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 516       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 517       continue;
 518     }
 519
 520     prev = blr;
 521     blr = (blocking_lock_record *)ubi_slNext(blr);
 522   }
 523 }
 524
 525 /****************************************************************************
 526  Return True if the blocking lock queue has entries.
 527 *****************************************************************************/
 528
 529 BOOL blocking_locks_pending(void)
 530 {
 531   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 532   return (blr == NULL ? False : True);
 533 }
 534
 535 /****************************************************************************
 536  Process the blocking lock queue. Note that this is only called as root.
 537 *****************************************************************************/
 538
 539 void process_blocking_lock_queue(time_t t)
 540 {
 541   blocking_lock_record *blr = (blocking_lock_record *)ubi_slFirst( &blocking_lock_queue );
 542   blocking_lock_record *prev = NULL;
 543
 544   if(blr == NULL)
 545     return;
 546
 547   /*
 548    * Go through the queue and see if we can get any of the locks.
 549    */
 550
 551   while(blr != NULL) {
 552     connection_struct *conn = NULL;
 553     uint16 vuid;
 554     files_struct *fsp = NULL;
 555
 556     /*
 557      * Ensure we don't have any old chain_fsp values
 558      * sitting around....
 559      */
 560     chain_size = 0;
 561     file_chain_reset();
 562     fsp = blr->fsp;
 563
 564     conn = conn_find(SVAL(blr->inbuf,smb_tid));
 565     vuid = (lp_security() == SEC_SHARE) ? UID_FIELD_INVALID :
 566                   SVAL(blr->inbuf,smb_uid);
 567
 568     DEBUG(5,("process_blocking_lock_queue: examining pending lock fnum = %d for file %s\n",
 569           fsp->fnum, fsp->fsp_name ));
 570
 571     if((blr->expire_time != -1) && (blr->expire_time > t)) {
 572       /*
 573        * Lock expired - throw away all previously
 574        * obtained locks and return lock error.
 575        */
 576       DEBUG(5,("process_blocking_lock_queue: pending lock fnum = %d for file %s timed out.\n",
 577           fsp->fnum, fsp->fsp_name ));
 578
 579       blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 580       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 581       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 582       continue;
 583     }
 584
 585     if(!become_user(conn,vuid)) {
 586       DEBUG(0,("process_blocking_lock_queue: Unable to become user vuid=%d.\n",
 587             vuid ));
 588       /*
 589        * Remove the entry and return an error to the client.
 590        */
 591       blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 592       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 593       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 594       continue;
 595     }
 596
 597     if(!become_service(conn,True)) {
 598       DEBUG(0,("process_blocking_lock_queue: Unable to become service Error was %s.\n", strerror(errno) ));
 599       /*
 600        * Remove the entry and return an error to the client.
 601        */
 602       blocking_lock_reply_error(blr,NT_STATUS_ACCESS_DENIED);
 603       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 604       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 605       unbecome_user();
 606       continue;
 607     }
 608
 609     /*
 610      * Go through the remaining locks and try and obtain them.
 611      * The call returns True if all locks were obtained successfully
 612      * and False if we still need to wait.
 613      */
 614
 615     if(blocking_lock_record_process(blr)) {
 616       free_blocking_lock_record((blocking_lock_record *)ubi_slRemNext( &blocking_lock_queue, prev));
 617       blr = (blocking_lock_record *)(prev ? ubi_slNext(prev) : ubi_slFirst(&blocking_lock_queue));
 618       unbecome_user();
 619       continue;
 620     }
 621
 622     unbecome_user();
 623
 624     /*
 625      * Move to the next in the list.
 626      */
 627     prev = blr;
 628     blr = (blocking_lock_record *)ubi_slNext(blr);
 629   }
 630 }